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- 6. Tarek Sobh University of Bridgeport, USA Xingguo Xiong University of Bridgeport, USA Prototyping of Robotic Systems: Applications of Design and Implementation
- 7. Prototyping of robotic systems: applications of design and implementation / Tarek Sobh and Xingguo Xiong, editors. p. cm. Includes bibliographical references and index. Summary: “This book provides a framework for conceptual, theoretical, and applied research in robotic prototyping and its applications, covering the prototyping of various robotic systems including the complicated industrial robots, the tiny and delicate nanorobots, medical robots for disease diagnosis and treatment and simple robots for educational purposes”--Pro- vided by publisher. ISBN 978-1-4666-0176-5 (hardcover) -- ISBN 978-1-4666-0177-2 (ebook) -- ISBN 978-1-4666-0178-9 (print & perpetual access) 1. Robots--Design and construction. 2. Prototypes, Engineering. I. Sobh, Tarek M. II. Xiong, Xingguo, 1973- TJ211.P77 2012 629.8’92--dc23 2011043975 British Cataloguing in Publication Data A Cataloguing in Publication record for this book is available from the British Library. All work contributed to this book is new, previously-unpublished material. The views expressed in this book are those of the authors, but not necessarily of the publisher. Managing Director: Lindsay Johnston Senior Editorial Director: Heather Probst Book Production Manager: Sean Woznicki Development Manager: Joel Gamon Development Editor: Michael Killian Acquisitions Editor: Erika Gallagher Typesetter: Adrienne Freeland Cover Design: Nick Newcomer, Lisandro Gonzalez Published in the United States of America by Information Science Reference (an imprint of IGI Global) 701 E. Chocolate Avenue Hershey PA 17033 Tel: 717-533-8845 Fax: 717-533-8661 E-mail: cust@igi-global.com Web site: http://www.igi-global.com Copyright © 2012 by IGI Global. All rights reserved. No part of this publication may be reproduced, stored or distributed in any form or by any means, electronic or mechanical, including photocopying, without written permission from the publisher. Product or company names used in this set are for identification purposes only. Inclusion of the names of the products or companies does not indicate a claim of ownership by IGI Global of the trademark or registered trademark. Library of Congress Cataloging-in-Publication Data
- 8. List of Reviewers Aarne Halme, Aalto University, Finland Ahmad Taher Azar, International Journal of System Dynamics Applications (IJSDA), USA Ahmed Elsayed, University of Bridgeport, USA Akif Durdu, Middle East Technical University, Turkey Andrew Goldenberg, University of Toronto, Canada Aydan M. Erkmen, Middle East Technical University, Turkey Ayssam Elkady, University of Bridgeport, USA Barkan Ugurlu, Toyota Technological Institute, Japan Brandon J. Stark, Utah State University, USA Elif Kongar, University of Bridgeport, USA Emin Faruk Kececi, Istanbul Technical University, Turkey Erdem Erdemir, Vanderbilt University, USA Gen’ichi Yasuda, Nagasaki Institute of Applied Science, Japan Haibo Huang, Robotics and Micro-systems Center, Soochow University, China Jack Toporovsky, University of Bridgeport, USA Jeremy Li, University of Bridgeport, USA Jianbing Hu, Schlumberger Ltd., USA Jorge Manuel Miranda Dias, University of Coimbra, Portugal Junling Hu, University of Bridgeport, USA Kathiravelu Ganeshan, Unitec Institute of Technology, New Zealand Lawrence Hmurcik, University of Bridgeport, USA Linfeng Zhang, University of Bridgeport, USA Madhav Patil, University of Bridgeport, USA Nicola Ivan Giannoccaro, University of Salento, Italy Nicolae Gari, University of Bridgeport, USA Pierre Letier, Space Applications Services, Belgium Qing’an Zeng, North Carolina A&T State University, USA Sarosh Patel, University of Bridgeport, USA Sebahattin Topal, Middle East Technical University, Turkey Sedat Dogru, Middle East Technical University, Turkey Srihari Yamanoor, Stellartech Research, USA Tamás Haidegger, Budapest University of Technology and Economics, Hungary Vicente Parra Vega, University of Texas at Dallas, USA Vikas Reddy Enti, Kiva System, Inc., USA Xiaojun Wu, Data Storage Institute, A*STAR, Singapore Xuefu Zhou, University of Cincinnati, USA YangQuan Chen, Utah State University, USA
- 9. Preface. .................................................................................................................................................xiii Acknowledgment.................................................................................................................................xxi Section 1 Robotic Prototyping: Methodologies and Design Optimizations Chapter 1 Prototyping Robotic Systems: Methodology and Case Studies. .............................................................. 1 Andrew Goldenberg, Engineering Services Inc. (ESI), Canada & University of Toronto, Canada Chapter 2 Modeling and Simulation of Discrete Event Robotic Systems Using Extended Petri Nets.................. 51 Gen’ichi Yasuda, Nagasaki Institute of Applied Science, Japan Chapter 3 Optimal Design of Three-Link Planar Manipulators Using Grashof’s Criterion.................................. 70 Sarosh H. Patel, RISC Laboratory, University of Bridgeport, USA Tarek Sobh, RISC Laboratory, University of Bridgeport, USA Section 2 Implementation of Robotic Systems and their Applications Chapter 4 AggieVTOL: A Vertical Take Off and Landing Unmanned Aerial Vehicle Platform for Personal Remote Sensing................................................................................................................. 85 Brandon J. Stark, Center for Self-Organizing & Intelligent Systems (CSOIS), Utah State University, USA YangQuan Chen, Center for Self-Organizing & Intelligent Systems (CSOIS), Utah State University, USA Mac McKee, The Utah Water Research Laboratory, Utah State University, USA Table of Contents
- 10. Chapter 5 Portable Haptic Arm Exoskeleton. ....................................................................................................... 122 Pierre Letier, Space Applications Services N.V./S.A., Belgium André Preumont, Université Libre de Bruxelles (ULB), Belgium Chapter 6 Prototyping and Real-Time Implementation of Bipedal Humanoid Robots: Dynamically Equilibrated Multimodal Motion Generation........................................................................................................... 146 Barkan Ugurlu, Toyota Technological Institute, Japan Atsuo Kawamura, Yokohama National University, Japan Chapter 7 Prototyping of Fully Autonomous Indoor Patrolling Mobile Robots.................................................. 182 Xiaojun Wu, Data Storage Institute, A*STAR, Singapore Bingbing Liu, Institute for Infocomm Research, A*STAR, Singapore Jun-Hong Lee, Dyson Operations, Inc. Singapore Vikas Reddy, Kiva Systems, Inc. USA Xi Zheng, Thinking Dots, Inc. Singapore Chapter 8 Prototyping of Lunabotic Excavator Robotic System......................................................................... 217 Nicolae Gari, University of Bridgeport, USA Xingguo Xiong, University of Bridgeport, USA Section 3 Robotic Systems for Medical Applications Chapter 9 Medical Robotics................................................................................................................................. 253 Ahmad Taher Azar, International Journal of System Dynamics Applications (IJSDA), USA M. Sam Eljamel, The University of Dundee, UK Chapter 10 Surgical Robots: System Development, Assessment, and Clearance.................................................. 288 Tamás Haidegger, Budapest University of Technology and Economics, Hungary Chapter 11 Design and Evaluation of a Piezo-Driven Ultrasonic Cell Injector..................................................... 327 Haibo Huang, Robotics and Micro-systems Center, Soochow University, China Hao Su, Worcester Polytechnic Institute, USA Changhai Ru, Robotics and Micro-systems Center, Soochow University, China Chapter 12 Prototyping of Robotic Systems in Surgical Procedures and Automated Manufacturing Processes..................................................................................................................... 356 Zheng (Jeremy) Li, University of Bridgeport, USA
- 11. Section 4 Prototyping of Robotic Systems for Other Applications Chapter 13 Robotic Hardware and Software Integration for Changing Human Intentions................................... 380 Akif Durdu, Middle East Technical University, Turkey Ismet Erkmen, Middle East Technical University, Turkey Aydan M. Erkmen, Middle East Technical University, Turkey Alper Yilmaz, Photogrammetric Computer Vision Laboratory, The Ohio State University, USA Chapter 14 A Framework for Prototyping of Autonomous Multi-Robot Systems for Search, Rescue, and Reconnaissance............................................................................................................................. 407 Sedat Dogru, Middle East Technical University, Turkey Sebahattin Topal, Middle East Technical University, Turkey Aydan M. Erkmen, Middle East Technical University, Turkey Ismet Erkmen, Middle East Technical University, Turkey Chapter 15 A Heuristic Approach for Disassembly Sequencing Problem for Robotic Disassembly Operations. ...................................................................................................................... 438 Ahmed ElSayed, University of Bridgeport, USA Elif Kongar, University of Bridgeport, USA Surendra M. Gupta, Laboratory for Responsible Manufacturing, Northeastern University, USA Compilation of References................................................................................................................ 448 About the Contributors..................................................................................................................... 487 Index.................................................................................................................................................... 495
- 12. Preface. .................................................................................................................................................xiii Acknowledgment.................................................................................................................................xxi Section 1 Robotic Prototyping: Methodologies and Design Optimizations In this section, the general design methodologies and implementation strategies used in robotic prototyp- ing are discussed. Several case studies are included to demonstrate the concepts. Prior to prototyping, a robotic system should be properly designed. A set of optimized design parameters needs to be decided, and the design can be verified with simulations. The modeling and design optimization strategies for some specific robotic systems are proposed. These include the modeling and simulation of discrete event robotic systems using extended Petri nets, as well as the design optimization of three-link planar manipulators using Grashof’s criterion. Chapter 1 Prototyping Robotic Systems: Methodology and Case Studies. .............................................................. 1 Andrew Goldenberg, Engineering Services Inc. (ESI), Canada & University of Toronto, Canada This chapter offers an overview of the general methodology and implementation strategy of robotic sys- tems, supported by several case studies. Based on his practical industry experience as well as his teaching and research results as a faculty in a university, the author shares some unique views and perceptions about robotic prototyping. Three case studies are demonstrated in the chapter, which include a mobile tracker, a robot arm for internal operations in nuclear reactors, and a MRI-guided robot for prostate focal surgery. The chapter presents a general framework for robotic systems prototyping. Chapter 2 Modeling and Simulation of Discrete Event Robotic Systems Using Extended Petri Nets.................. 51 Gen’ichi Yasuda, Nagasaki Institute of Applied Science, Japan In this chapter, the modeling and simulation of discrete event robotic systems using extended Petri nets are introduced. Extended Petri nets are used as a prototyping tool for expressing real-time control of robotic systems.Acoordination mechanism is introduced to coordinate the event activities of the distrib- uted machine controllers through friability tests of shared global transitions. The proposed prototyping method allows a direct coding of the inter-task cooperation by robots and intelligent machines from the conceptual Petri net specification. Detailed Table of Contents
- 13. Chapter 3 Optimal Design of Three-Link Planar Manipulators Using Grashof’s Criterion.................................. 70 Sarosh H. Patel, RISC Laboratory, University of Bridgeport, USA Tarek Sobh, RISC Laboratory, University of Bridgeport, USA This chapter introduces a novel and effective algorithm for design optimization of three-link planar manipulators using Grashof’s criterion. A three-link serial manipulator can be converted into a four- link closed chain based on a simple assumption, so that its mobility can be studied using Grashof’s criterion. With the help of Grashof’s criterion, a designer can not only predict and simulate the mobil- ity of a manipulator during its design, but also map and identify the fully-dexterous regions within its workspace. A simple algorithm using Grashof’s criterion for determining the optimal link lengths of a three-link manipulator is proposed in order to achieve full dexterity at the desired regions of the workspace. Section 2 Implementation of Robotic Systems and their Applications In this section, the prototyping and implementation of various robotic systems for different applications are introduced. These include unmanned aerial vehicles, a portable haptic arm exoskeleton, a bipedal humanoid robot, an indoor fully autonomous patrolling mobile robot, as well as a lunabotic regolith excavator robot. The architecture design, modeling and implementation of each robot are discussed in detail. The design and implementation strategies used in the prototyping of these robots may be extended to other similar robotic systems as well. Chapter 4 AggieVTOL: A Vertical Take Off and Landing Unmanned Aerial Vehicle Platform for Personal Remote Sensing................................................................................................................. 85 Brandon J. Stark, Center for Self-Organizing & Intelligent Systems (CSOIS), Utah State University, USA YangQuan Chen, Center for Self-Organizing & Intelligent Systems (CSOIS), Utah State University, USA Mac McKee, The Utah Water Research Laboratory, Utah State University, USA In this chapter, the implementation of AggieVTOL, a vertical take-off and landing unmanned aerial vehicleplatformforpersonalremotesensingisproposed.UnmannedAerialVehicles(UAVs)forcivilian applications are part of a rapidly growing sector in the global aerospace industry that has only recently begun to gain traction. This chapter presents the AggieVTOL, a modular multi-rotor rotorcraft UAV prototype platform, and an overview of the prototyping phase of its development, including design parameters and the implementation of its modular subsystems. Performance results demonstrate the effectiveness of the platform. Chapter 5 Portable Haptic Arm Exoskeleton. ....................................................................................................... 122 Pierre Letier, Space Applications Services N.V./S.A., Belgium André Preumont, Université Libre de Bruxelles (ULB), Belgium Inthischapter,theprototypingofaportablehapticarmexoskeletonforaerospaceapplicationisproposed. The proposed robot is a seven-degree-of-freedom force-reflective device able to produce a haptic render- ing of the human arm, either as master for teleoperation of a slave robot, or in interaction with a virtual reality. The project was conducted on behalf of the European Space Agency (ESA) as a prototype of the master device used for teleoperation of future anthropomorphic space robotic arms on the International
- 14. Space Station (ISS). The proposed robot can decrease the number of extravehicular activities of the astronauts, even for complex situations. Chapter 6 Prototyping and Real-Time Implementation of Bipedal Humanoid Robots: Dynamically Equilibrated Multimodal Motion Generation........................................................................................................... 146 Barkan Ugurlu, Toyota Technological Institute, Japan Atsuo Kawamura, Yokohama National University, Japan This chapter presents the prototyping and real-time implementation of bipedal humanoid robots based on dynamically equilibrated multimodal motion generation. The authors aim at developing a contem- porary bipedal humanoid robot prototyping technology by utilizing a mathematically rigorous method to generate real-time walking, jumping and running trajectories. The main strategy is to maintain the overall dynamic equilibrium and to prevent undesired rotational actions for the purpose of smooth maneuvering capabilities while the robot is in motion. This is achieved by utilizing the Zero Moment Point criterion in spherical coordinates so that it is possible to fully exploit its properties with the help of Euler’s equations of motion. Chapter 7 Prototyping of Fully Autonomous Indoor Patrolling Mobile Robots.................................................. 182 Xiaojun Wu, Data Storage Institute, A*STAR, Singapore Bingbing Liu, Institute for Infocomm Research, A*STAR, Singapore Jun-Hong Lee, Dyson Operations, Inc. Singapore Vikas Reddy, Kiva Systems, Inc. USA Xi Zheng, Thinking Dots, Inc. Singapore In this chapter, the prototyping of fully autonomous indoor patrolling mobile robots is proposed. The mobile robot employs a modular design strategy by using the ROS (Robot Operating System) software framework, which allows for an agile development and testing process. The primary modules—omni-directional drive system, localization, navigation, and autonomous charging—are described in detail. Special effort is put into the design of these modules to make them reliable and robust in order to achieve autonomous patrolling without human intervention. The experimental test results prove that an indoor mobile robot patrolling autonomously in a typical office environ- ment is realizable. Chapter 8 Prototyping of Lunabotic Excavator Robotic System......................................................................... 217 Nicolae Gari, University of Bridgeport, USA Xingguo Xiong, University of Bridgeport, USA In this chapter, the prototyping of a lunar excavator robotic system for participating in the 2010 NASA Lunar Excavating Competition is proposed. Remotely controlled by an operator using a computer via Wi-Fi telecommunication, the autonomous lunabotic excavator can perform the tasks of excavating regolith stimulant, collecting it in the excavator’s dumpster, and depositing it into the assigned collec- tor box. The design and implementation of the lunabotic excavator with all the functional modules are discussed. It is an interesting project, and the design strategy may offer hints leading to new and effective robotic excavators for planetary exploration.
- 15. Section 3 Robotic Systems for Medical Applications Medical robotics is another important application of robotics technology. Robotics is being used for minimally invasive surgery (MIS), remote surgery (telesurgery), patient monitoring and stabilization, rehabilitation facilities, as well as medical training. Minimally invasive surgery based on medical ro- bots results in smaller incisions, shorter hospital stays, improved prognoses and reduced cost. Medical robotics will significantly impact the health care industry, resulting in revolutionary change to disease diagnosis and treatment. This section offers a comprehensive review about the interdisciplinary field of medical robotics. The prototyping of a piezo-driven ultrasonic cell injector and some other medical robots is introduced. Chapter 9 Medical Robotics................................................................................................................................. 253 Ahmad Taher Azar, International Journal of System Dynamics Applications (IJSDA), USA M. Sam Eljamel, The University of Dundee, UK In this chapter, a comprehensive overview about medical robotics is proposed. Medical robotics focuses on developing electromechanical devices for clinical applications. This chapter begins with an introduc- tion to robotics, followed by a historical review of their use in medicine. Clinical applications in several different medical specialties are discussed. Various medical robots, ranging from commercial industrial products to the research works of university labs, are introduced. The technology challenges and areas for future research in medical robotics are also discussed. Chapter 10 Surgical Robots: System Development, Assessment, and Clearance.................................................. 288 Tamás Haidegger, Budapest University of Technology and Economics, Hungary Inthischapter,thesystemdevelopment,assessmentandclearanceofsurgicalrobotsareintroduced.Many different surgical robot prototypes have been developed, while only a handful have passed clearance procedures and have been released to the market. This is mostly due to the difficulties associated with medical device development and approval, especially in those cases when some form of manipulation and automation is involved. This chapter presents major aspects of surgical robotic prototyping and current trends through the analysis of various international projects. The system planning, development, validation and clearance of surgical robots are discussed. Chapter 11 Design and Evaluation of a Piezo-Driven Ultrasonic Cell Injector..................................................... 327 Haibo Huang, Robotics and Micro-systems Center, Soochow University, China Hao Su, Worcester Polytechnic Institute, USA Changhai Ru, Robotics and Micro-systems Center, Soochow University, China In this chapter, the design and evaluation of a piezo-driven cell injection system for automatic batch injection of suspended cells is presented. The elimination of mercury enables wide applications of the proposed cell injection technology in a number of cell manipulation scenarios. Ultrasonic vibration micro-dissection (UVM) theory is utilized to analyze the piezo-driven cell injection process, and lateral oscillation of injector pipettes is investigated. Experiments on the cell injection of a large amount of zebrafish embryos indicate that the injector pipette is capable of piercing through cell membranes with low injection speed, high success rate, and almost no deformation of the cell wall.
- 16. Chapter 12 Prototyping of Robotic Systems in Surgical Procedures and Automated Manufacturing Processes..................................................................................................................... 356 Zheng (Jeremy) Li, University of Bridgeport, USA In this chapter, two example projects about the prototyping of robotic systems in surgical procedures and automated manufacturing processes are reported.The prototyping and implementation of the robotic system is a scientific and technological integration of robotic system design, development, testing, and application.This chapter describes the recent development and applications of robotic systems to surgery procedures in biomedical engineering and automated manufacturing processes in industry. It includes the design and development, computer-aided modeling and simulation, prototype analysis, and testing of robotic systems in these two different applications. Section 4 Prototyping of Robotic Systems for Other Applications In this section, the prototyping and implementation of robotic systems for some other applications are discussed. Human-robot interaction (HRI) studies the dynamics of interaction between humans and robots. Research work on the use of robotic hardware and software integration to change human in- tentions is reported. Search and rescue (SAR) robots are used to save lives in environments which are unsafe for human first responders. The prototyping of autonomous multi-robot systems for search, rescue and reconnaissance is proposed. Finally, a heuristic approach based on a genetic algorithm for robotic disassembly sequencing optimization is reported. Chapter 13 Robotic Hardware and Software Integration for Changing Human Intentions................................... 380 Akif Durdu, Middle East Technical University, Turkey Ismet Erkmen, Middle East Technical University, Turkey Aydan M. Erkmen, Middle East Technical University, Turkey Alper Yilmaz, Photogrammetric Computer Vision Laboratory, The Ohio State University, USA This chapter proposes interesting research on the use of robotic hardware and software integration to change human intentions. Reshaping of human intention is achieved by robots moving in certain direc- tions that have been determined a priori through observations from the interactions of humans with the objects in the scene. Being among the few studies on intention reshaping, the authors exploit spatial information by learning a Hidden Markov Model (HMM) of motion that is tailored for intelligent robotic interaction. The results obtained using the proposed approach show promising performance in reshaping the detected intentions. Chapter 14 A Framework for Prototyping of Autonomous Multi-Robot Systems for Search, Rescue, and Reconnaissance............................................................................................................................. 407 Sedat Dogru, Middle East Technical University, Turkey Sebahattin Topal, Middle East Technical University, Turkey Aydan M. Erkmen, Middle East Technical University, Turkey Ismet Erkmen, Middle East Technical University, Turkey
- 17. In this chapter, the prototyping of autonomous multi-robot systems for search, rescue and reconnaissance is proposed. Prototyping modules of heterogeneous multi-robot networks and their design characteristics are discussed. Prototyping takes two different scenarios into consideration. One is search and rescue in unstructured complex environments. The other is connectivity maintenance in Sycophant wireless sen- sor networks, which are static ecto-parasitic clandestine sensor networks mounted incognito on mobile agents, using only the agent’s mobility without intervention, and are cooperating with sparse mobile robot sensor networks. Chapter 15 A Heuristic Approach for Disassembly Sequencing Problem for Robotic Disassembly Operations. ...................................................................................................................... 438 Ahmed ElSayed, University of Bridgeport, USA Elif Kongar, University of Bridgeport, USA Surendra M. Gupta, Laboratory for Responsible Manufacturing, Northeastern University, USA Robots are also used for the disassembly of electronic products that reach their end-of-life cycle. Due to the large volume of components in electronic products, an efficient algorithm is needed to optimize the sequence in robotic disassembly operations. This chapter introduces a genetic algorithm-based methodology to develop disassembly sequencing for end-of-life products. The proposed algorithm is proven to be effective in optimizing the sequence of robotic disassembly operation and improving the efficiency of the process. Compilation of References................................................................................................................ 448 About the Contributors..................................................................................................................... 487 Index.................................................................................................................................................... 495
- 18. xiii Preface The field of Robotics focuses on the study of design, simulation, implementation, and operation of robots for various applications. As programmable or remotely-controlled electromechanical machines, robots can perform certain tasks autonomously or semi-autonomously. Ever since the early eras of robotics, there has been a long history of utilizing robots to assist or replace human work. Nowadays, robotics technology has been intensively used in numerous industries including, but not limited to: manufactur- ing,automobileassembly,electronics,foodprocessing,consumergoods,pharmaceuticals,healthscience, mining, planetary exploration, military weapons, et cetera. Robots can significantly improve the effi- ciency, reliability, accuracy and throughput of a traditional workforce. They are especially suitable to replace humans in performing tasks that are difficult, monotonous and tedious. They are also a good choice for delivering results in harsh environments that are too dangerous or life threatening for humans, such as workplaces with nuclear radiation, poisonous chemicals, fire, lack of oxygen or extremely high/ low temperatures. Robotics, as a segment of the broader science of automation, has achieved tremendous progress in recent decades due to advances in related supporting technologies such as computing, con- trol system, wireless communication, cameras and electronic sensing, as well as micro and nanotechnol- ogy. Many new robotic systems have been designed and implemented for various applications. For example, modern technologies in motion control, speech recognition, facial expression and human-robot interaction have led to bipedal humanoid robots that can walk, talk or even perform simple communica- tion with human. As another example, robotic surgery utilizes computer-controlled robots to support a range of surgical procedures. Robotic surgery has enabled remote surgery, minimally invasive surgery and unmanned surgery. Compared to traditional surgery, robotic surgery has the advantages of high precision, miniaturization, smaller incisions, decreased blood loss, less pain, and quicker healing time. Prototyping is the process of building an early sample or model of a system to prove the design concept or detect potential problems before batch fabrication. Prototyping is an important activity in engineering. Prototyping a design helps in determining system parameters, validating design concepts, debugging problems, and achieving optimized design of the system. The prototype can be used to verify design and measurements (e.g. performance, kinematics, function, architecture) and provide important information for the designer to identify which design option is better and which component may need further development and testing. Robotics is one of the industrial design fields in which prototyping is crucial for improved functionality. Prototype development is a good test for checking the viability of a proposed system. Prototyping of a robotic system is never trivial. Starting from the design specifications, a designer needs to decide the architecture of the robot best suitable for the specific application. Design optimization should be performed to decide the design parameters of the robot. During the implementa- tion process, potential problems or challenges may be exposed. Some of the problems may be due to
- 19. xiv the design flaws and it may be necessary to further adjust or revise the design based on the information fed back from the prototyping process. Multiple iterations may be necessary before the robotic systems can be finally prototyped successfully. The prototyping of a robotic system involves many important decisions, such as deciding the architecture of the system, choosing proper materials and the electro- mechanical components, determining the design parameters and deciding the algorithmic control of the robotmodules(kinematics,inversekinematics,dynamics,trajectoryplanning,analogcontrol,anddigital computer control). The design for each individual module should be decided, such as the mechanical structure, power, actuation, control, telecommunication, and data-acquisition systems. Various CAD (ComputerAided Design) and CAM (ComputerAided Manufacturing) tools are available for the design- ers to design, visualize, and simulate a robotic system rapidly and cost-effectively. Computer simulation allows the discovery of potential problems before the robots are actually manufactured. The objective of this book is to cover the most recent research frontiers and trends in robotic prototyp- ing.This book discusses the design and implementation of various robotic systems and their applications, from complicated industrial robots to state-of-the-art micro and nanorobots for surgical applications, as well as robotic systems for educational purposes. Robotic systems are diverse in their structures, working principles, implementation strategies and applications. Newly emerging technologies such as computer vision, wireless communication, micro and nanotechnologies have been utilized in robots to enhance their function and performance. As a result, new robots have been proposed and prototyped for various new applications. This book aims to cover the prototyping of various robotic systems including complicated industrial robots, tiny and delicate nanorobots, medical robots for disease diagnosis and treatment, as well as simple robots for educational purposes. The design, implementation, and technical considerations in the prototyping of various robotic systems are discussed. Some case studies of robotic prototyping for industrial, medical, aerospace, and education applications are included. The applications of such robotic systems will be introduced. The new trends and most recent research frontiers in robotic prototyping and the applications are also covered. This book is intended for researchers, industry engineers, and students working in the fields of robotics, control systems, medical electronics, computer vision, micro/nanotechnology, aerospace and other automation fields. It is also a general reference book for individuals who are interested in robotic design, prototyping and their applications. The book is designed to cover the design and implementation of a wide range of robots for different applications. Each category is accompanied with case studies. The content of this book is arranged as follows. The book begins with an introduction about general design methodologies and implementation strategies used in robotic prototyping. Several case studies are included to illustrate the concepts. Prior to prototyping, a robotic system should be designed following the required specifications, and the design parameters should be decided. Chapter 2-3 introduces the theoretical design and optimization strategies of general robotic systems. This includes the modeling and simulation of discrete event robotic systems using extended Petri Nets in Chapter 2, and the design opti- mization of three-link planar manipulators using Grashof’s Criterion in Chapter 3. Chapter 4 to Chapter 8 discuss the prototyping of various robotic systems for different applications, which include unmanned aerial vehicles, a portable haptic arm exoskeleton, a bipedal humanoid robot, an indoor fully autonomous patrolling mobile robot, as well as a lunabotic regolith excavator robot. The architecture, design con- siderations and implementation of each robot are discussed in detail. Chapters 9-12 are devoted to the topic of medical robotics. Chapter 9 provides a comprehensive overview of various medical robots being developed around the world, and future trends in this exciting field. Chapter 10 introduces the system development, assessment and clearance of surgical robotics. Chapter 11 proposes a piezoelectric driven
- 20. xv ultrasonic cell injector that may be used as a powerful tool in medical research and disease treatment. Chapter 12 introduces two example projects about prototyping robotic systems for surgical procedures and automated manufacturing processes. Human-robot interaction (HRI) is another exciting field in robotics. It will eventually lead to robots that can directly interact with humans, which can assist people and improve human performance in daily and task-related activities. Chapter 13 discusses an interesting project addressing the use of robotics to change human intentions. Search and rescue (SAR) robots can help people to perform search and rescue tasks in environments that are unsafe or life-threatening for humanrescuers,suchasunderwater,followinganearthquake,orothernaturaldisasters.Thedevelopment of SAR robots must address challenges in robotic sensing, mobility, navigation, planning, integration and teleoperation control. Chapter 14 introduces a framework for prototyping autonomous multi-robot systems for search, rescue, and reconnaissance. Finally, robotic systems are also used for the automation of disassembly process of electronic products for recycling when they come to the end of life cycle. The disassembly process is generally very complex due to the large amount of components involved, and an optimization of the sequence is needed to improve efficiency and reduce cost. Chapter 15 proposes a heuristic approach for optimizing disassembly sequencing for robotic disassembly operations. The content of each chapter are briefly summarized below. In Chapter 1, an overview of the general methodology for prototyping robotic systems is introduced, and some case studies are given to illustrate the whole sequence. Robotics research is the framework for studying hypotheses and conjectures, synthesizing new ideas, and discovering phenomena in the context of robotic systems. Prototypes are normally used for proof-of-principle and functional demonstration. In many cases they are part of the product design and development process. In direct relationship to suc- cessful demonstrations of new technology using prototypes and the existence or emergence of related markets, prototypes could end up being used or redesigned for commercialization. The market may even accept, albeit rarely, a demonstration prototype as the first generation product. Yet, such prototypes normally would be re-designed at a later stage as commercial prototypes. The process of prototyping is complex, costly, and risky. This chapter provides an experience-based framework of prototype devel- opment and commissioning. It introduces elements learned directly from the practice that encompass aspects of project management, technology development process, and commercialization in the context of Small and Medium Enterprises (SMEs). The contents of this chapter are based mainly on the author’s practical experience of leading an SME technology developer. The author is also a faculty member working as a researcher and teacher. Because of the interrelationship between research and technology development, his views and perception of the topic may be unique, and they are personal. The chapter presents a general framework for robotic systems prototyping. Three case studies are demonstrated in the chapter, which include a mobile tracker, a robot arm for internal operations in nuclear reactors, and a MRI-guided robot for prostate focal surgery. The case studies back up the points made in the chapter and help the reader understand the outlined concepts. Theimplementationofanyroboticsystemshouldstartfromdesignoptimizationandsimulation.Many different robotic systems may belong to the same category and follow similar theoretical modeling and simulation strategies. In Chapter 2, the modeling and simulation of discrete event robotic systems using extended Petri nets are introduced. This chapter deals with modeling, simulation, and implementation problems encountered in robotic manufacturing control systems. Extended Petri nets are adopted as a prototyping tool for expressing real-time control of robotic systems and a systematic method based on hierarchical Petri nets is described for their direct implementation. A coordination mechanism is intro- duced to coordinate the event activities of the distributed machine controllers through friability tests
- 21. xvi of shared global transitions. The proposed prototyping method allows a direct coding of the inter-task cooperation by robots and intelligent machines from the conceptual Petri net specification, so that it increases the traceability and the understanding of the control flow of a parallel application specified by a net model. This approach can be integrated with off-the-shelf real-time executives. Control software using multithreaded programming is demonstrated to show the effectiveness of the proposed method. Design optimization is the key step to achieving a set of optimized design parameters for the robotic system. Chapter 3 introduces a novel and effective algorithm for optimal design of three-link planar manipulators, using Grashof’s criterion. The design of robotic manipulators is dictated by a set of pre- determinedtaskdescriptionsandperformanceparameters.Theseperformanceparametersareoftendefined in terms of workspace dexterity, manipulability, and accuracy. Many serial manipulator applications require that the manipulator have full dexterity about a work piece or a pre-defined trajectory, that is, to approach the given point within the workspace with all possible orientations about that point. Grashof’s criterion defines the mobility of four-link closed chain mechanisms in relation to its link lengths. A simple assumption can convert a three-link serial manipulator into a four-link closed chain so that its mobility can be studied using Grashof’s criterion. With the help of Grashof’s criterion, a designer can not only predict and simulate the mobility of a manipulator during its design, but also map and identify the fully-dexterous regions within its workspace. Mapping of the dexterous workspace is helpful in ef- ficient task placement and path planning. A simple algorithm using Grashof’s criterion for determining the optimal link lengths of a three-link manipulator is proposed in order to achieve full dexterity at the desired regions of the workspace. The generated design is also tested by applying joint angle limitations. Starting with Chapter 4, the design and prototyping of various robotic systems are introduced. In Chapter 4, a vertical take-off and landing unmanned aerial vehicle platform for personal remote sensing is proposed. Unmanned Aerial Vehicles (UAVs) for civilian applications are in a rapidly growing sector in the global aerospace industry that has only recently begun to gain traction. In this relatively immature field, there is such a steep learning curve that it can be difficult for research groups to begin development of well designed UAV systems. In this chapter, the authors present the AggieVTOL, a modular multi- rotor rotorcraft UAV prototype platform, and an overview of the prototyping phase of its development, including design parameters and the implementation of its modular subsystems. Performance results demonstrate the effectiveness of the platform. The design and implementation strategies in this project can be extended to other UAV prototyping as well. In Chapter 5, the prototyping of a portable haptic arm exoskeleton for aerospace application is pro- posed. The proposed robot is a seven-degree-of-freedom force-reflective device able to produce haptic rendering of the human arm, either as master for teleoperation of a slave robot, or in interaction with a virtual reality. The project was conducted on behalf of the European Space Agency (ESA) as a proto- type of the master device used for teleoperation of future anthropomorphic space robotic arms on the International Space Station (ISS). The motivation is to decrease the number of extravehicular activities of the astronauts, even for complex situations. The structure of a portable anthropomorphic exoskeleton of seven degrees of freedom was selected by ESA due to the fact that it allows a more intuitive control of anthropomorphic slave arms, and it also allows multiple contact points, offering a larger workspace (comparable to the human arm). Besides, being attached on the astronaut, the system involves only internal forces (it is self-equilibrated) and can be used in zero-gravity. Chapter 6 presents the authors’ work on prototyping and real-time implementation of bipedal hu- manoid robots. Dynamically equilibrated multimodal motion generation is required for the proposed bipedal humanoid robot. This chapter is aimed at describing a contemporary bipedal humanoid robot
- 22. xvii prototyping technology, accompanied with a mathematically rigorous method to generate real-time walking, jumping and running trajectories that can be applied to this type of robots. The main strategy in this method is to maintain the overall dynamic equilibrium and to prevent undesired rotational actions for the purpose of smooth maneuvering capabilities while the robot is in motion. In order to reach this goal, the Zero Moment Point criterion is utilized in spherical coordinates so that it is possible to fully exploit its properties with the help of Euler’s equations of motion. Such a strategy allows the designer to characterize the rotational inertia and therefore the associated angular momentum rate change terms, so that undesired torso angle fluctuations during walking and running are well suppressed. It allows the designer to prevent backwards-hopping actions during jumping as well. The proposed approach is vali- dated by performing simulations using a precise 3D simulator and conducting experiments on an actual bipedal robot. Results indicate that the method is superior to classical methods in terms of suppressing undesired rotational actions, such as torso angle fluctuations and backwards-hopping. In Chapter 7, the prototyping of fully autonomous indoor patrolling mobile robots is proposed. The mobile robot employs a modular design strategy by using the ROS (Robot Operating System) software framework, which allows for an agile development and testing process. The primary modules - omni- directional drive system, localization, navigation, and autonomous charging are described in detail. Special effort is put into the design of these modules to make them reliable and robust in order to achieve autonomous patrolling without human intervention. The experimental test results prove that an indoor mobile robot patrolling autonomously in a typical office environment is realizable. In Chapter 8, the prototyping of a lunar excavator robotic system is discussed. The lunabotic excava- tor was developed for participating in the 2010 NASA Lunar Excavating Competition. Being remotely controlled by an operator using a computer via Wi-Fi telecommunication, the autonomous lunabotic ex- cavator can perform the tasks of excavating regolith stimulant, collecting it in the dumpster, and dumping it into the assigned collector box. The excavator include multiple modules including mechanical frames, front/rear wheels, excavating conveyor, steering system, dumping system, power supply and distribu- tion system, actuation system, switch control system, data acquisition system and telecommunication system. The design and implementation of the lunabotic excavator with all the functional modules are discussed. The design concepts used in this project may offer hints leading to new and effective robotic excavators for planetary exploration. Roboticsisalsofindingexcitingapplicationsinthebiomedicalfield,leadingtoanewinterdisciplinary field of medical robotics. Medical robotics will significantly impact the health care industry, resulting in revolutionary change to the way doctors diagnose and treat diseases. For example, robotics is already being used for minimally invasive surgery (MIS), remote surgery (telesurgery), patient monitoring and stabilization, rehabilitation facilities, as well as medical training. Minimally invasive surgery based on medical robots results in smaller incisions, shorter hospital stays, improved prognoses and reduced cost. Chapter 9 to Chapter 12 are specifically devoted to this important and exciting new field. In Chapter 9, a comprehensive overview about medical robotics is proposed. As an interdisciplinary field, medical robotics focuses on developing electromechanical devices for clinical applications. The goal of this field is to enable new medical techniques by providing new capabilities to the physician or by providing as- sistance during surgical procedures. Medical robotics is a relatively young field, as the first recorded medical application occurred in 1985 for a brain biopsy. However, medical robotics has tremendous potential for improving the precision and capabilities of physicians when performing surgical procedures and it is believed that the field will continue to grow as improved systems become available. This chapter begins with an introduction to robotics, followed by a historical review of their use in medicine. Clini-
- 23. xviii cal applications in several different medical specialties are discussed. Various medical robots, ranging from commercial products from industry, to the research works of university labs are introduced. The technology challenges and areas for future research in medical robotics are also discussed. In Chapter 10, the system development, assessment, and clearance of surgical robots are introduced. InformationTechnologyandroboticshavebeenintegratedintointerventionalmedicineforover25years. Their primarily aim has always been to provide patient benefits through increased precision, safety and minimal invasiveness. Nevertheless, robotic devices should allow for sophisticated treatment methods that are not possible by other means. Several hundreds of different surgical robot prototypes have been developed, while only a handful passed clearance procedures and were released to the market. This is mostly due to the difficulties associated with medical device development and approval, especially in those cases when some form of manipulation and automation is involved. This chapter presents major aspects of surgical robotic prototyping and current trends through the analysis of various international projects. It spans across the phases from system planning, to development, validation and clearance. Research in medical robotics also leads to new and improved tools for medical research and disease treatment. In Chapter 11, the design and evaluation of a piezoelectric driven ultrasonic cell injector is proposed. Piezo drill, a new cell injection technology that utilizes piezo-driven pipettes with a very small mercury column for cell injection, was first invented in 1995. It was then successfully applied to intracytoplasmic sperm injection (ICSI) in a variety of mammal species. Although this technique sig- nificantly improves the survival rates of the ICSI process, shortcomings such as the damage to the cell membrane due to large lateral tip oscillations of the injector pipette, complexity of operation and toxicity of mercury immensely limit its application. In this chapter, a novel piezo-driven cell injection system for automatic batch injection of suspended cells is presented. It has a simplified operational procedure and better performance than previous piezo-driven cell injectors. Specifically, this new piezo-driven cell injector design has three advantages. First, by centralizing the piezo oscillation energy on the injector pipette, it eliminates the vibration amplitude of other parts of the micromanipulator. Second, a small piezo stack is sufficient to perform the cell injection process. Third, detrimental lateral tip oscillations of the injector pipette are attenuated to a satisfactory amount even without mercury column. The elimina- tion of mercury enables wide applications of the proposed cell injection technology in a number of cell manipulation scenarios. Ultrasonic vibration micro-dissection (UVM) theory is utilized to analyze the piezo-drivencellinjectionprocess,andlateraloscillationofinjectorpipettesisinvestigated.Experiments on cell injection of a large amount of zebrafish embryos indicate that the injector pipette is capable of piercing through cell membranes with low injection speed and almost no deformation of the cell wall, but with a high success rate. In Chapter 12, two example projects about the prototyping of robotic systems in surgical procedures and automated manufacturing processes are reported.The prototyping and implementation of the robotic system is a scientific and technological integration of robotic system design, development, testing and application.This chapter describes the recent development and applications of robotic systems to surgery procedures in biomedical engineering and automated manufacturing processes in industry. It includes design and development, computer-aided modeling and simulation, prototype analysis and testing of robotic systems in these two different applications. Human-robot interaction (HRI) is another new and increasingly popular field that studies the dy- namics of interaction between humans and robots. Many researchers are putting effort into developing robotic systems that are capable of performing direct, safe and effective interactions with humans. It is also interesting to look into how robotics can be used to affect human behavior and intentions. As an
- 24. xix interdisciplinary field, HRI requires knowledge about robotics, psychology, communication, ethics and cognitive science. Chapter 13 proposes interesting research about using robotic hardware and software integration to change human intentions. Estimating and reshaping human intentions are among the most significant topics of research in the field of human-robot interaction. This chapter provides an overview of intention estimation literature on human robot interaction and introduces an approach to how robots can voluntarily reshape estimated intentions. The reshaping of the human intention is achieved by robots moving in certain directions that have been determined a priori through observations from the interac- tions of humans with the objects in the scene. Being among the few studies on intention reshaping, the authors exploit spatial information by learning a Hidden Markov Model (HMM) of motion that is tailored for intelligent robotic interaction. The algorithmic design consists of two phases. First, an approach is used to detect and track a human to estimate his/her current intention. Later, this information is used by autonomous robots that interact with the detected human to change the estimated intention. In the tracking and intention estimation phase, postures and locations of the human are monitored by applying low-level video processing methods. In the latter phase, learned HMM models are used to reshape the estimated human intention. This two-phase system is tested on video frames taken from a real human- robot environment. The results obtained using the proposed approach show promising performance in reshaping the detected intentions. Robots have been widely used in search and rescue tasks in environments that are dangerous or life- threatening to human rescue workers. During an earthquake, nuclear accident or other disaster, rescue robots can save many lives without endangering the human rescue workers. In Chapter 14, a framework fortheprototypingofautonomousmulti-robotsystemsforsearch,rescueandreconnaissanceisproposed. Robots consistently help humans in dangerous and complex tasks by providing information about, and executing tasks in disaster areas that are highly unstructured, uncertain, possibly hostile, and sometimes not reachable by humans directly. Prototyping autonomous multi-robot systems in disaster scenarios both as hardware platforms and software can provide the foundational infrastructure for comparing the performance of different methodologies developed for search, rescue, monitoring and reconnaissance. In this chapter, the prototyping modules of heterogeneous multi-robot networks and their design char- acteristics are discussed. Two different scenarios are considered in the prototyping process. One is the search and rescue in unstructured complex environments. The other is the connectivity maintenance in Sycophantwirelesssensornetworks,whicharestaticecto-parasiticclandestinesensornetworksmounted incognito on mobile agents, using only the agent’s mobility without intervention, and are cooperating with sparse mobile robot sensor networks. Robots are also used for the disassembly of electronic products when they come to the end-of-life cycle. Electronic products enter the waste stream rapidly due to technological enhancements. Their parts and material recovery involve significant economic and environmental gain. To regain the value added to such products, a certain level of disassembly may be required. Disassembling electronic products is a tedious and potentially dangerous process, and robots are increasingly used for this operation. Due to large amount of components in electronic products, an efficient algorithm is needed to optimize the sequenceinroboticdisassemblyoperations.InChapter15,aheuristicapproachfordisassemblysequenc- ing problem for robotic disassembly operations is proposed. Disassembly operations are often expensive and the complexity of determining the best disassembly sequence increases as the number of parts in a product grows. Therefore, it is necessary to develop methodologies for obtaining optimal or near op- timal disassembly sequences to ensure efficient recovery process. To that end, this chapter introduces
- 25. xx a Genetic Algorithm-based methodology to develop disassembly sequencing for end-of-life products. A numerical example is presented to provide and demonstrate better understating and functionality of the algorithm. The proposed algorithm is proven to be effective in optimizing the sequence of robotic disassembly operation and improving the efficiency of the process. Finally, this book is a joint effort of robotic researchers and engineers from around the world. The editors hope that this book will be helpful to researchers and engineers engaged in the design and proto- typing of modern robotic systems, as well as students of mechanical engineering, electrical engineering, and computer engineering who are interested in the robotics field. Tarek Sobh University of Bridgeport, USA Xingguo Xiong University of Bridgeport, USA
- 26. xxi Acknowledgment This book is a result of the contributions and work of many robotic researchers and engineers around the world. It is the collection of a wide range of research results from the robotics scientific research community, including scientists and engineers from universities, research institutes, and industry. The design, prototyping of various robotic systems, and their applications are explored. We hope you will enjoy the book. As editors, we would like to take this opportunity to thank all our chapter authors for their valuable contributions to this book. We are also very grateful to the editorial advisory board mem- bers for their valuable advice and suggestions to ensure the quality of the book. Special thanks to all our reviewers for their valuable time and efforts in reviewing the book chapters, as well as their constructive comments to help our authors. Tarek Sobh University of Bridgeport, USA Xingguo Xiong University of Bridgeport, USA
- 27. Section 1 Robotic Prototyping: Methodologies and Design Optimizations
- 28. 1 Copyright © 2012, IGI Global. Copying or distributing in print or electronic forms without written permission of IGI Global is prohibited. Chapter 1 DOI: 10.4018/978-1-4666-0176-5.ch001 INTRODUCTION Robotics research is the framework for studying hypotheses and conjectures, synthesizing new ideas, and discovering phenomena in the context of robotic systems. The research usually leads to peer-reviewed publications, occasional patent- ing, and in some cases, construction of working prototypes that may or may not have commercial value or intent. Prototypes are normally used for proof-of-principle and functional demonstration. In many cases they are part of the product design and development process. In direct relationship to successful demonstrations of new technology using prototypes, and the existence or emergence of related markets, the prototypes could end up being used or redesigned for commercialization. Andrew Goldenberg Engineering Services Inc. (ESI), Canada & University of Toronto, Canada Prototyping Robotic Systems: Methodology and Case Studies ABSTRACT This chapter provides an experience-based framework of prototypes development and commissioning. It introduces elements learned directly from the practice that encompass aspects of project management, technology development process, and commercialization in the context of Small and Medium Enterprises (SMEs). The contents of this chapter are based mainly on the author’s practical experience of leading an SME technology developer. The author is also a faculty member working as a researcher and teacher. Because of the interrelationship between research and technology development, his views and percep- tion of the topic may be unique, and they are personal. The chapter presents a general framework for robotic systems prototyping. To back up the points made in the chapter, three case studies of robotic prototyping are included to help the reader perceive the outlined concepts.
- 29. 2 Prototyping Robotic Systems The market may even accept, albeit rarely, a demonstration prototype as the first generation product. Yet, such prototypes normally would be re-designed at a later stage as commercial pro- totypes. The process of prototyping is complex, costly, and risky. A prototype is an early sample or model of a concept,idea,orprocessthatwouldallowprelimi- nary functional and performance evaluation to be conducted through experimentation. Prototypes serve as benchmarks against which the original idea is measured in terms of representation, func- tionality,andevenmanufacturabilityandservicing of the related product. The early evaluation helps alleviatetheconcernsanduncertaintyastowhether or not the new product will actually perform what and how it is expected to, as new product designs, more often than not, raise unexpected problems. Aprototypeisusedaspartoftheproductdesign process to allow exploring design alternatives, and confirm functionality and performance prior to proceeding to the design of the commercial prototype, and much earlier than introducing the new product to the market. Prototypes are used also to confirm and verify market interest and readinesstoacceptinganewproduct;othertimes, prototypes are used to verify the performance or suitability of a specific product or features for executing certain tasks. In some product development organizations, prototyping specialists are employed - individu- als with specialized skills and training in general prototypedevelopmentandfabricationtechniques. They can help bridge between theoretical ideas, designs, and the fabrication of commercial pro- totypes as a prelude to products. This chapter addresses prototyping from the perspective of new robotic product development. It is a process similar to general prototyping, but itdoesnotbenefitfromtheanticipatedexperience with earlier products as reference. Prototyping in robotics is by-and-large opportunistic, and constrained only by the original idea and its functional purpose. BACKGROUND Thereisnogeneralagreementonwhatconstitutes a “prototype” and the word is often used inter- changeably with the word “model,” which may cause confusion. In general, “prototypes” can be of four basic types: Proof-of-Principle Prototype: In electro- mechanics it is sometimes called a breadboard. This type of prototype is used to test specific features of the intended design without attempt- ing to emulate the visual appearance, required materials, or assembly process. Such prototypes areusedtoidentifywhichdesignfeaturesmaynot work, and where further in-depth development and testing is necessary. FunctionalPrototype:Thistypeofprototype allows designers to explore the basic size, look and functionality of a new product. It can help assess ergonomic factors, and provides insight into industrial design of the product. These pro- totypes capture the intended design aesthetic and emulate the appearance of the intended product. These prototypes are intended for marketing, and are generally durable enough to be shown and use by representative users and consumers. The prototypes are suitable for use in critical design reviews and photo shoots for sales literature. Commercial Prototype: This prototype pro- vides the final design, aesthetics, materials and functionality of the intended product. The con- structionofthisfullyworkingfull-scaleprototype is the ultimate test of the original concept and the engineers’ final check for design flaws to allow further improvements to be made before larger production runs begin. Production Prototype: The difference be- tweenthecommercialandproductionprototypesis expressedbythreeelements:(i)Material-produc- tionmaterialsmayrequirespecificmanufacturing processesinvolvinghighercapitalcoststhanwhat was used for prototyping; (ii) Manufacturing - often expensive and time consuming unique tooling may be required to fabricate some custom
- 30. 3 Prototyping Robotic Systems designedparts;and(iii)Fidelity-finalproduction design often requires extensive effort for design for manufacturing that was avoided in the earlier prototypes. In the product development cycle, the proto- type iterations may be labelled to be an “Alpha” prototype,“Beta”,etc.Howeverthesedistinctions are only semantically relevant, as they do not provide intrinsic meaning. Ingeneral,functional-to-commercialprototyp- ing costs are substantially greater than the cost of the final production prototype due mainly to extensive labor involved in the development and design. Prototypes must be amenable to revisions of the design for the purposes of refinement and improvement of functionality. It is also possible to use prototype testing to reduce the risk that a design will not perform acceptably, though pro- totypes generally cannot eliminate all risk. There are pragmatic and practical limitations to the ability of a prototype to match the final intended performanceoftheproduct,andsomeallowances and engineering judgement are often required before moving forward to the production design. Building prototypes is also expensive in terms of material and related machine shop tasks, and software coding. As an alternative, “rapid- prototyping” techniques are used for the initial prototypes, which implement some, but not all, of the design features. This allows designers to rapidly and inexpensively test the elements of the design that are most likely to generate problems. Rapidprototypingisnotaddressedinthischapter. Anotherapproachtoreducingcostofprototyp- ing is Virtual Reality models. Virtual Reality is used to provide a software alternative to physical prototyping.Thesoftwaretoolsareveryadvanced, but certain nuances of the prototype system behaviour cannot be reconciled through the VR technologyavailabletoday.Suchmodelsareused morefrequentlyatthe‘proof-of-principle’stage,as they are devoid of physical properties for real life experimentation that functional-to-commercial prototypes have. The topic of prototype development is usu- ally addressed in the research literature as an afterthought; that is, the prototype is only used to showpiece the main intent: demonstration of a new idea, concept, or phenomenon. The actual process of prototyping is not discussed in the robotics literature because it is not considered as research. It can be found in trade literature of systems,products,andcomponents,butthere,the provided information is submerged and devoid of details in order to maintain proprietary control, andensureenforcementandcontrolofintellectual property. Prototyping is a systematic process that can be described by the following streamlined phases: Discovery, Design, Manufacturing, and Acceptance Testing. In practice, these phases are brokendownintothefollowingsteps:information gathering, concept synthesis, development and design, manufacturing, testing, and evaluation. These steps emphasize the streamlined aspect of the prototyping process. Prototyping is not a mocking-up of the final product.As the prototyping work progresses, the commercialprototypebecomestheproductmodel. After building and experimenting with the model and modifications are made to it, the prototyping process as a development phase ends, leading to the production prototype. That is the model that becomes the actual product. ISSUES IN PROTOTYPING Expression of Idea The method of prototyping as an expression of an idea affects the intensity of development, mo- tivation, communication, and outcome of design. Most of the practices revolve around the creative process, but they include also the concerns with thefutureproductcostanditsservicing.Nonethe- less,thepracticeofprototypingismainlyaffected by the experience of the designers involved, in
- 31. 4 Prototyping Robotic Systems particular their previous design experience with prototyping. This is productive and counter- productive at the same time. The innovativeness isbestexpressedwhenthereisexperience,butnot ifitlimitsthedeveloperfromseeking“out-of-the- box” solutions for a new design because of past experience. Open-mindedness is best expressed when theexperienceis onlyused toavoidpitfalls, rather than to guide and channel the designer to already known solutions. Cost Frequently, the challenge is in the details of a prototype. In physically generating a working piece of robotic hardware, 80% of the total work gets finished in 20% of the total time required to finish the project. Invariably the design of the prototype will change as the project development advances. The potential customer might have suggestions; the information collected during the experimentation might raise issues of concern. Thus, variability of the internal design of the product becomes a serious concern, although the overall functionality and external aesthetics may be already satisfied. The developers must be potentially ready for re-design and modification. Thisimpliesthattheprototypesmusthaveflexible software and hardware design architectures. To reduce cost and simplify the design, at times the single goal of a prototype is to move to the next phase of the design process, whether that next step involves a more refined version or the final production prototype. A designer has to consider always that parts of the system might be reused in the next phase, thus focus any extra effort on thosereusableparts.Unfortunately,thisapproach raises the cost of prototyping in terms of both time and materials. Intellectual Property Intellectual Property protection is a serious con- cern that has a paramount importance commer- cially. The exposure of the early prototypes at the inopportune time, or in an unsuitable forum, may jeopardize the chances of protection. This issue is part of the overall management of the product development. Prototype Development Theprototypedevelopment,aspartoftheproduct development cycle, is subject to many factors that influence the outcome. If the planning and execution of the prototype development and sub- sequent commercial exposure are not performed adequately, even an ingenious idea with great market potential may lead to limited commercial value. Ingeneral,productdevelopmentmustfollowa rigorous Project Management methodology. The componentsofthemethodologyare:StudyofRe- quirements, Determination of Feasibility, Defini- tion of Specifications, Design and Programming, Manufacturing,Integration,Testing,Acceptance, Training of Users, and Installation. The various components usually follow each other serially. The requirements study begins after the original idea has been fully understood. Soon after it has begun, the specifications are completed. When the specifications are defined, the preliminary design begins. Shortly after the integration of the prototype the verification, acceptance testing, and the user training begin. The milestone dates of the prototype development are usually the re- quirementsdefinition,preliminarydesignreview, critical design review, and acceptance testing. The steps described in this chapter are the generic form of Project Management method- ology. These steps are generally followed for project management of any prototyping process. The only difference in robotic prototyping is that overlapping of some of the project phases listed aboveoccurs.Actually,robotprototypingprovides more of an iteration of phases instead of a non- overlappingsequenceandcontinuationofphases.
- 32. 5 Prototyping Robotic Systems The next sections address the issues of project management, system engineering, and quality assurance in the context of prototyping. PROTOTYPE DEVELOPMENT METHODOLOGY Project Management Project Management methodologies emphasize scheduling, cost control, meeting of milestones, and interim user’s signoffs. The interim user’s signoffsaremoreimportantthantherequirements or the final product acceptance. The objective of project management is to directthedevelopment,deployment,field-testing, and delivery of the prototype. The project man- agementobjectivesalsoincludetheidentification andmitigationofrisks(technical,operational,and programmatic) associated with the development. This is done progressively as part of the Prelimi- naryDesignReview,CriticalDesignReview,and final acceptance with the client/user involvement up to a formal approval. Projectmanagementisbasedonamanagement plan whose scope is to provide a structured, man- ageable, traceable, and accountable approach to projectdevelopment.Theplanincludesallocation of resources, control, and management of risk. The prototype project management methodology is based on the following fundamental elements of generic project management: • Team: Project Management Team (PMT) constituted of experienced managers who are also technical experts. • Process: Project Management Process (PMP) based on typical four standard phases of project life cycle: Discovery, Design, Manufacture and Integration, and Acceptance Tests. • Plan: Project Management Plan in- cludes Work Break-down Structure, Work Packages, and Personnel allocation, Schedule, Managerial Risk Assessment, Milestones, and Deliverables. • Control: Project Management Control includes Project Scope, Schedule, Cost, Quality, Human Resource, Communications, Integration, Risk, and Performance. Team: The PMT is supported by a Systems Engineering Team (SET) who ensures that the product satisfies all technical requirements set forth. Due to the highly integrated nature of the development across multiple disciplines, key teammembersareinvolvedinbothSETandPMT activities. The intent of this overlap is to ensure balanceandconsistencybetweenalltechnicaland managerial activities. Process: The PMP evolves in four phases. They cover all stages of project life cycle. • Discovery Phase: This phase includes the derivation of system specifications, gener- ation of conceptual designs, modeling, and system trade-offs. Through an in-depth re- view of the project’s objectives, the PMT develops a thorough understanding of the required technologies. The PMT identi- fies all relevant project tasks, their inter- relationships, and the resources needed to complete the project on schedule, within budget, while meeting all stakeholders’ex- pectations. This phase consolidates the ini- tial project’s Work Breakdown Structure, Work Packages, and Schedule. As well, this phase addresses Design Concepts, Modeling, and System Trade-offs. • Design Phase: The PMT and SET ana- lyze the information gathered during the Discovery Phase, and using its findings de- velop, document, and validate a workable project plan that conforms to the nominal objectives. The PMT works very closely at this stage with the SET team that, in paral-
- 33. 6 Prototyping Robotic Systems lel, leads and monitors the System Design Phase. During this phase, the SET’s level of activity intensifies and the PMT operates in a “surveillance” (control) mode, tracking project progress and deliverables, inter- vening when necessary to steer the project back onto the right track. Subcontractors’ interactions are monitored closely by the SET. • Manufacturing and Integration Phase: The design is implemented, integrated, tested, and modified until all project objectives are met. Subcontractors’ system integra- tion is part of this phase of work. Payload integration is included in this phase. • Final Acceptance Phase: This phase in- cludes all activities needed for the final prototype field testing. The PMT will de- termine the appropriate project activities to ensure that the prototype will operate reli- ably for its intended use. Following the test and verifications the PMT and SET will assess whether or not further upgrades are necessary, or the project is completed. Plan: The plan includes the four phases of system development • Phase 1: Discovery Phase ◦ ◦ Objective: Deriving system require- ments from the high-level perfor- mance and technical requirements. ◦ ◦ Constraints: Derived system re- quirements are subject to Project Management Team (PMT) review prior to release. The PMT is respon- sible for ensuring that all high-level requirements are being addressed. ◦ ◦ Benefits: Detailed functional require- ments and design constraints of each subsystem can be derived. Overall system performance measures are defined. Interface requirements are defined. Trade-offs and comparison metrics are defined. Work schedules and budget estimates are broken down by subsystem. • Phase 2: Design Phase ◦ ◦ Activity 2.1: Concept Design ▪ ▪ Objectives: The concept of the system design is generated. Requirements and functional analysis for all levels of sub- systems are generated. Planning of the design process and veri- fication and testing stages are performed. ▪ ▪ Constraints: Results of trade-off analyses; available technology; available resources. ▪ ▪ Benefits: Firmed up develop- ment plan; trade-off analyses to optimize the concept; detailed subsystem and interface re- quirements are generated; pre- pare Concept Design Review. ◦ ◦ Activity 2.2: Preliminary Design ▪ ▪ Objectives: Specifications for all subsystems, assemblies and components are generated. Hardware and software require- ments are defined in detail. ▪ ▪ Constraints: System require- ments; hardware & software test and validation plans; prototype development plan; tasks and missions to be performed. ▪ ▪ Benefits: Definition of internal and external interfaces; pre- liminary design verifications; software data interfaces; bread- board models and prototypes; long-lead procurement; verifi- cation plan for each subsystem; prepare Preliminary Design Review.
- 34. 7 Prototyping Robotic Systems ◦ ◦ Activity 2.3: Detailed Design ▪ ▪ Objectives: Hardware and soft- ware development towards production. ▪ ▪ Constraints: Interfaces design requirements. ▪ ▪ Benefits: Detailed design and preparation for Critical Design Review; verification plans; pre- prototype bench testing; inter- face design testing; production phase planning. • Phase 3: Manufacturing & Integration Phase ◦ ◦ Objectives: Manufacture and assem- bly of system; complete software development. ◦ ◦ Constraints: Software verification and testing; updated test procedures; system integration planning. ◦ ◦ Benefits: Prototype operational; field deployment operations plan; system integration test plan; payload integra- tion test plan; perform Preliminary Acceptance Review. • Phase 4: Final Acceptance Phase ◦ ◦ Objectives: Integrated system testing. ◦ ◦ Constraints: Integration testing plan; upgrading requirements. ◦ ◦ Benefits: System integration test- ing procedures; perform Integrated System Acceptance. Control: Management control objectives are design, schedule, cost, and programmatic • Design Data Control: Design data must be controlled with high diligence by the PMT and SET due to the fact that some of the project activities bear a high tech- nical risk, and could delay the project and increase expenditures. This control is very complex and not totally repeatable at various stages of the project. It requires a mixture of standard project management approaches, technical knowledge, and ex- perience, to allow effective assessment of the impact of departures from, and adapta- tion of the plan in the technical context, and the costs involved. Design Data Control is performed by using the Configuration and Data Management Plan (CDMP) facility. • Schedule Control: At the start of the project, an overall schedule based on the project Work Breakdown Structure and Work Package Definitions is prepared by the PMT. Tasks are coded numerically, es- timated in terms of number of hours and projected end dates, and personnel are as- signed accordingly. The schedule is up- dated at least once monthly. The updates are based on reported progress and related revised estimates of end dates of various project tasks. Additional tasks are added to the schedule as necessary. Major devia- tions from the schedule are addressed im- mediately by assigning backup personnel to the tasks that are behind or anticipated to fall behind schedule, or by implement- ing other measures of compensation for delays. Schedule control includes monitoring of personnel’s, collaborators’and consultants’ schedules.Frequentmeetingsortelecomsare held with the collaborators and consultants to ascertain the timing of their schedules and delivery of milestones, and face-to-face meetings are held regularly or as often as necessary. Special attention must be given to monitoring of tasks that provide risks of overrunsinscheduleand/orcost.Theseitems are primarily those identified in the PMT’s Management Risks list. • Cost Control: Before the start of the proj- ect, Cost Control spreadsheets of estimat- ed costs for labour, parts, materials, and
- 35. 8 Prototyping Robotic Systems subcontractors’ work are generated. The spreadsheets are updated regularly (e.g. monthly) or as often as necessary monthly to include expenditures planned, earned value, and amounts actually paid and en- cumbered. Balances are weighed against original estimates, and major deviations are addressed immediately, or, in case of a budget overrun, a resolution on cost re- duction is implemented. In the event of an unavoidable cost overrun, the PMT will decide if: (i) specifications must be rede- fined; or (ii) change of scope of work is to be considered in consultation with client. • Programmatic: Contractual Reporting and Meetings Control: Contractual re- porting and milestone meetings are very important and must be closely monitored from the start of the project. The PMT must ensure that these obligations are met in terms of both contents and schedules. System Engineering System Engineering integrates human resource expertise with company’s procedures, practices, and internal working methods. This approach is adapted to each specific project’s objectives. The system engineering process is the key element in the prototype development. A System Engi- neering Team (SET) with participants from each developmentcollaboratoranddisciplineleadsthe technologydevelopment.TheSETisdelegatedto execute its authority on technology development, andsupporttheprogrammaticrequirementsofthe PMT. Throughout the project the SET interacts withtheQualityAssurancepersonnel,andensures thatalldesignactivitiesareproperlydocumented, andthattheConfigurationandDataManagement (CADM) practices are followed with the intent of facilitating the storage, sharing of information, and exchanging data between various teams. The PMT and SET function in coordination at all times during the life of the project to ensure the delivery of the commitments. A good choice is to have most of the members of the SET be also members of the PMT. System Engineering Team Functions The main functions of the SET are to plan the technology development, to guide and monitor the design activities, to manage the integration and testing, and to support the acceptance tests. System Engineering covers: • System Specifications: Determination of system specifications based on requirements • Concept design: Concept formulation based of system specifications • System Modeling: System level model to study feasibility of compliance to system requirements • System Trade-off Studies: Performance of system trade-offs; definition of metrics for comparison; and decision criteria for each trade-off • System Design: Lead, monitor, and inte- grate the efforts of the various design teams • Performance Measure and Evaluation: Definition of system performance measures and methods of performance evaluation • System Validation and Verification Plan: Generation of test plans that verify the sys- tem and subsystem requirements; monitor the execution of these plans In addition, the SET has the following re- sponsibilities: • Manage system configurations, interfaces, and design data • Support the PMT on all programmatic is- sues including management of technical risks
- 36. 9 Prototyping Robotic Systems • Manage product and data documentation that will enable operation, maintenance, and updating of the prototype In principle, the SET has the role of plan- ning the technical work in accordance with the requirements, advising the PMT on requirements of human resources, monitoring development progress,andprovidingnecessarysupporttomeet the contractual requirements undertaken by the PMT. The SET tracks the technical development and reports to the PMT on either satisfaction or departure from expected results or milestones. In turn, the PMTinforms the SETif the cost is under control and schedules are met, whether alloca- tion of resources is possible, and if the client is completely satisfied with the status of the project. The SET must operate on the basis that it has access to the most expert resources of the enter- prise, and it benefits from direct link to the PMT on matters of project control, resource allocation, schedules, and liaison with the client. The SET is, in fact, the team that de-facto, and in the end, deliverstheproduct.ThePMTistheteamthathas the contractual responsibility for the deliverables tobeonscheduleandbecompliantwithallsystem requirements. System Engineering Process The systems engineering process is hierarchical, and consists of a series of phases, all of which are intended to take the overall system requirements through detailed specifications and verification/ validationmethodstothefinaldeliverables.These phases are a combination of the activities listed in the previous sections. The SET directs the entire technical team throughout each phase, checks the results of the design activities against the overall system requirements, and takes corrective action whennecessaryunderthesupervisionofthePMT. Phase1:Discovery-Requirements,Concept, Modeling, and Trade-offs Thisinitialphaseinvolvesderivingsystemspecifi- cationsfromthehigh-levelrequirementsprovided by the client. The input to this phase includes: • High level system requirements • Identified measures of performance evaluation • Known system constraints • Identified external interfaces Using this input, the SET applies functional analysis techniques to map the high level require- ments into system functions. These functions are thenindividuallybrokendownhierarchicallyinto sub-functions until detailed system specification are obtained. Once the set of specifications is obtained, it is checked back against the original system requirements in order to ensure that they are all met. The system specifications are subject to PMT approval prior to release.The PMTreview under- takes to confirm that the specifications capture the requirements of the system. The review also verifies that the specifications possess the fol- lowing attributes: • Verifiable: they are stated in a way that they can be verified using an objective analysis or testing procedure • Traceable: they must be traceable to a higher level requirement to ensure that all high level requirements are flowed-down into derived specifications • Achievable: they must be technically fea- sible within the allotted time and budget • Unambiguous: they must have only one possible interpretation • Consistent: they must not be in conflict with each other
- 37. 10 Prototyping Robotic Systems • Complete: they must contain all of the necessary information to confirm that all high level requirements are met (in con- text, rationale, and terms of reference) The output of this phase provides: • System and subsystems design specifications • System concept and configurations of subsystems • Potential system trade-offs and compari- son metrics • System and subsystem performance measures • System and subsystems interfaces definition • Work schedules and budget estimates bro- ken down by subsystems Phase 2: System Design Phase Using the output of the first phase as input, the SET launches the design phase, in which detailed concepts are generated in response to the system and subsystem specifications. The system and subsystems specifications are further refined into subassembly and components, and testing plans that verify the system and subsystem compli- ance with the original high level requirements are issued. Duringthesystemdesignphase,thetrade-offs studies are further analyzed in detail. Trade-off studies are used to support the decisions made in regards to requirements and the selection of ap- propriate design alternatives. The trade-off stud- ies focus on key system performance parameters such as weight, power consumption, range and reliability of operation. Trade-off studies must also be supported by cost and schedule impact analyses. The results of these trade-off studies complement the detailed system description, and balance the requirements with other factors such as cost, manufacturability and complexity. Long-leaditemsareaparticularareaofconcern fortheSETduringthesystemdesignphase.Items that have long procurement schedules must be identified early in the design process. The system design must be frozen around these long-lead items so that they may be procured early in the design process, ensuring that their delivery will pose a low risk to the schedule. The SET must monitor the progress of the design team through technical reviews and spot- checks.Technicalrisksaremonitoredandupdated as necessary in order to ensure that appropriate mitigation steps are being taken. Issues and risks associated with the design are documented, and the SET conducts reviews to evaluate potential designalternatives,mitigationstrategiesorrever- siontocontingencyplans.TheSETprovidesinput to potential troubleshooting steps and conduct analyses to evaluate alternatives that present high technical or programmatic risk. The output of the system design phase is: • System and subsystem physical layouts • Detailed design, synthesis of solutions, and analysis of compliance with the specifications • System external and subsystem interfaces • System performance estimates • Detailed testing and verification plans • Detailed system integration and imple- mentation plans Phase 3: Manufacturing, Assembly, Integration This phase reflects the fact that in most high-tech environments the design team is best suited to assemble and test the overall system. The actual manufacture of parts may be done under subcon- tract elsewhere. The input to this phase is: • Mechanical design drawings • Electronics boards and circuits schematics • Flow charts for software coding
- 38. 11 Prototyping Robotic Systems The output of the phase is: • The assembled system fully functional • Bench test results • Performance verification and validation in virtual environments • Preparation of all hardware and soft- ware for Validation, Verification, and Acceptance Phase Phase 4: Verification, Validation, and Acceptance Verification is the activity that shows that the productwas“builtright”.Validationistheactivity that shows that the “right product” was built. The verification sub-phase ensures that the individual subsystems perform as per their specifications. Individual testing plans for each component or subsystem are developed during the detailed design phase, and these tests are carried out and documented during the verification sub-phase. Deficiencies identified during verification prompt a review of the design, manufacture and integration of the subsystem that is found to be deficient. In the event that there is a previously unidentified deficiency in the design, the SET allocates the required resources to perform a de- tailed analysis of the design and what alternative solutions could be implemented to correct the deficiency. In the event that there is a deficiency inmanufactureorintegration,theSETworkswith the supplier or integrator to identify the problems in their process and to correct the issue. During the validation sub-phase detailed de- signsandsystemarchitecturesarecheckedagainst the original high level requirements. Validation activities are carried out both in the lab (bench testing, hardware in the loop simulation), as well as in the field. In the event that validation activities yield a result indicating that the system does not meet the high-level requirements, the SET performs a review of the system concept of operations and a flow-down analysis of all of the requirements associated with the element of the system that fails the validation check. This flow down analy- sis will confirm that the concept responds to the missionrequirements,andthatthederivedsystem requirements and specifications are adequately interrelated. In doing so, the SET isolates the sourceofthedeficiencyandtakescorrectiveaction while maintaining the integrity of the remainder of the system. Acceptance tests include end-to-end tests and demonstrations of system functions. The tests are traceable to high-level system requirements, and upon successful demonstration, the project is considered as completed. The SET is also responsible for the documen- tation of all testing and verification activities. Upon final approval, the SET prepares the final validation data package. System Engineering Products Specifications System specifications are “flowed down” from high-level requirements to functional units of the project. The system specifications arise dur- ing both the Requirements Phase and the Design Phase of the product project, as a direct result of decomposition of the system into the product’s constituent subsystems. Theprogrammaticrequirementsaredefinedby aseriesofdocumentsdefiningtheoverallproduct systemarchitecture.Therequirementsaremapped intoproductspecifications.Thesearefurtherused to define the subsystems’ specifications. System Concept At the onset of the project, the SET guides the concept development. The conceptual design integrates the contributions of mechanical, elec- trical, and software development teams, as well operationalconstraints,interfacingrequirements, andscientificuserinput.Selectedconceptinvokes
- 39. 12 Prototyping Robotic Systems also the system trade-off studies. The complete systemrepresentedbyasimulationmodelprovides an end-to-end means of representing and docu- menting requirements, subsystems, constraints, and test plans. The model will be continually updated throughout the project as a means of trackingsubsystemsconfigurationsandinterfaces. Product Database Throughout the development, numerous designs, analyses and studies are performed to ensure conformancetosystemrequirements.Thesedocu- ments indicate the progress of the design and the decisions that influenced the final configuration. ThesedocumentsaremanagedbytheSETandare archived in a single database. Designs, analyses and studies are documented according to which high level requirement they act to satisfy, in order to provide traceability from the final design up to the analysis and ultimately up to the high level requirements.Bydelineatingwhichrequirements are satisfied by each analysis, future reconsidera- tions of specific requirements can be accommo- dated while ensuring that all other requirements are not impacted. Specifications, design drawings, interfaces, andanalysisreportsareusedtodocumentthespe- cificbaselinesofthesystem.Thesedocumentsare subjectedtoanapprovalprocess.Onceapproved, these documents are placed under configuration control and are handled according to the project Configuration and Data Management Plan. Product Baselines As the system life-cycle progresses, the product configurationgetsdefinedinaseriesofbaselines, consisting of approved documentation that is used to describe the technical specifications and interfaces of the baseline design. Each baseline identifies the mechanical, electrical and software elementsofthesystematvariousstagesofsystem development.Thegeneralflowofbaselinesorigi- natesfromthehigh-levelrequirements(Functional Baseline), to a system level description (Concept Baseline), to detailed design drawings and speci- fications (Design Baseline) and, finally, into a physical product which represents the “as built” state of the product (Product Baseline). Quality Assurance and Safety Program Quality Assurance To facilitate the required level of product quality, a system of procedures has to be adopted for the regulation of company activities, from proper project requirement identification to quality in- spections at different stages of prototype design and manufacturing. The responsibility for ensur- ing quality is shared. All employees, including top management, vendors and subcontractors are responsible for the quality of their work and of the products. This approach is provided and explained to each employee, to sub-contractors, and to vendors. The PMT retains project respon- sibility for the overall QualityAssurance System. The day-to-day operations related to this domain are managed by the Quality Assurance Manager. Most companies must achieve compliance with alltherequirementsofstandardQualityAssurance Requirements as described below. Certification to ANSI/ASQ Q 9001 (ISO 9001:2008) Mostcompanieshaveimplemented,orcommitted to implement, an ISO 9001 Quality Management System that provides surveillance of: • Design review, procurement, inspection, manufacturing process, inventory control and shipping • Training, audits/surveillance, metrology/ calibration, traceability • Detection, reporting of, and corrective ac- tion arising from, discrepancies
- 40. 13 Prototyping Robotic Systems • Failures and other indications of unsatis- factory quality, and test witnessing SMEsusuallyrecognizethattheyneedprofes- sional advice and direction in order to effectively implement such a comprehensive management system, and they mostly do it through subcon- tractedwork.Typicallysuchsubcontractorshavea variety of technical staff to assign to their clients. They are expert in interpreting, applying and au- diting ISO 9001 Quality Management Systems. They have experience working with engineered products in strict regulatory environments. Quality Assurance Implementation Plan QualityAssuranceImplementationPlans(QAIPs) are typically prepared to demonstrate how an or- ganization’sQualityManagementSystemapplies to a particular project or to provide confidence to a contracting agency that all of its regulatory and contractual requirements are understood, and will be met. AQAIPformatusuallyfollowstheinternation- ally accepted methodology for Quality Plans as defined in ISO 10005:2005 – Quality Manage- ment Systems Guidelines for Quality Plans. The QAIPisexpectedtoachievecompletecompliance withtheQualityAssuranceRequirementsofeach specific project. The QAIPis managed by the project’s Quality Assurance Manager. The Manager has overall responsibility for the preparation and dissemina- tion of the QAIP. The QAIP is meant to be brief and succinct and highlight contract-specific requirements and reference existing procedures and protocols within the project Quality Manage- ment System. A comprehensive QAIP addresses at least the following areas of Quality Assurance objectives: • Management Responsibilities • Control of Documents and Data • Control of Records • Configuration Management • Mechanical Systems Design • Electrical Systems and Software Design • Purchasing • Fabrication and Assembly • Identification and Traceability • Final Acceptance Testing • Customer Communication • Infrastructure and Work Environment • Training and Human Resources • Technical & Program Requirements • Reliability and Maintainability • Safety Program • Maintenance Program • Control of Nonconforming Product • Packaging and Delivery of Products • Metrology and Instrumentation Safety Program The PMT must be committed to preventing the accidental loss of any of its resources, including employees and physical assets. In fulfilling this commitment to protect both people and property, management provides and maintains a safe and healthy work environment in accordance with industry standards and in compliance with legis- lative requirements, and strives to eliminate any foreseeable hazards which may result in property damage, accidents, or personal injury/illness. Anycompanyrecognizesthattheresponsibility forhealthandsafetyareshared.Allemployeeswill be equally responsible for minimizing accidents withinthecompanyfacilitiesandonallworksites. Accidental loss can be controlled through good managementincombinationwithactiveemployee involvement. Safety is the direct responsibility of all managers, supervisors, employees, and con- tractors. All management activities must comply with company safety requirements as they relate to planning, operation and maintenance of facili- ties and equipment. All employees will perform theirjobsproperly,inaccordancewithestablished procedures and safe work practices.
- 41. 14 Prototyping Robotic Systems Design Failure Modes and Effects Analysis (DFMEA) Project safety and reliability engineers work with the SET to prepare a DFMEA to properly assess and quantify the risks associated with the final design in addition to MTTR and MTBF calcula- tions. Risks will include a series of issues: • Risk of degraded function in the field • Risk of loss of function in the field • Manufacturing risks posed by the designs • Testing risks posed by the designs • Premature failure or reliability risk in the designs • Safety risks to those building, operating or maintaining the vehicle. The DFMEA is usually prepared according to widely accepted industry standards: SAE J 1739, AIAG FMEA-4, and MIL-STD-1629A. Design risks are ranked according to Severity, Probability of Occurrence, and the Strength of the mitigation Strategy. The DFMEA assists in determining where safety risks exist and what hazard-prevention measures need to be imple- mented. It also helps in materials selection and determination of what components and functions needredundancyorhighsafety-factors.Anoutput oftheDFMEAistheDesignVerificationPlanand Report. It defines the project’s testing program in accordance with the risk profiles identified in the DFMEA. Configuration and Data Management Plan (CDMP) Overview The function of the CDMP is to define a reliable, sustainableandexpandableprocesswhichallows the development team to generate concurrently advanced and complex products while ensuring that the customer’s objectives and requirements are always met. Configuration Management (CM) provides a means of controlling changes to a design as it evolves from a set of objectives into a physical product operating in the field. CM requires stan- dardized processes in which the system design is base-lined at key milestones and that changes to the design are documented and traceable. Data Management (DM) provides a means of electronically storing design data on a file server whichiscapableoftrackingrevisionsandproduct history information. Further, the Data Manage- ment system involves a standardized process by whichdesigndataisbackedupandsecurelystored. The CM plan described herein is typical and is based upon the CMII-105B Standard for Product ConfigurationManagementbytheCMIIresearch institute (www.icmhq.com). The usual CADM system incorporates pro- cesses that are able to: • Identify the functional and physical char- acteristics of a design through all stages; • Accommodate and track changes to a design; • Maintain clear, concise and valid system requirements; • Ensure that system data is accurate and secure; • Ensure that best practices are re-used and regularly optimized; • Ensure that the designed systems meet their requirements; • Provide a means of assessing the total im- pact (schedule, cost, risk, safety) of chang- es to a design; • Provide control over change audits-in-process.
- 42. 15 Prototyping Robotic Systems All system and design data are stored in an electronic archive with a Redundant Array of Independent Disks (RAID) data storage scheme. The electronic archive is stored in a company server on the premises. Product Baselines As per MIL-STD-499B product configuration baselines define a set of well defined, approved and released configuration documents at various stagesofthesystemlifecycle.Currentconfigura- tiondocumentationconsistsofanexistingbaseline plus approved changes. Four baselines are used in the system development as follows: Functional Baseline The Functional baseline describes the overall functional requirements of a system. It defines the key capability and performance requirements of the system and all of the necessary interfaces and operating conditions to which the system must conform. Further, the System Requirements baseline defines the verification methods neces- sary to demonstrate that the system meets the stated requirements. TheFunctionalbaselinemaybeanextensionof the System Requirements. The top level require- mentsareaddressedwithanoverallsystemconcept and plan for action, which is formally embodied in the form of the contract bid or proposal. The Functional baseline may be extended by a System Hierarchy tree which defines the major subsystems in anticipation of the requirement to allocate high level requirements to specific subsystems. System trade-off studies are identified and carried out after the Functional baseline has been approved.Thus,theFunctionalbaselinerepresents a “safe” configuration to which the design team may revert in the event that the development baseline does not meet the system requirements or does not gain approval. Concept Baseline The Concept baseline is the result of a detailed Requirements Analysis and Trade-off study process. The SET decomposes the high level system requirements into derived and allocated requirements within the subsystem hierarchy. System trade-offs are performed to determine the optimal allocated design configuration. Each configurationthenpossessesitsownsetofdetailed requirements and preliminary design documents (i.e.sketches,schematics,blockdiagrams)which addressthederivedhighlevelsystemrequirements as allocated to each configuration. These design documents are subject to approval and represent the system specifications which are required in order to move forward with a detailed design. Detailed part selection and design proceed after the approval of the Concept baseline. Thus, the Concept baseline represents a “safe” design to which the development team may revert in the event that issues arise during the development of the Build-To baseline. Design Baseline The Design (or “Build-To”) baseline represents the approved detailed designs of the system. The Design baseline is the result of detailed system design and analysis. It contains all approved documentation (drawings, bills of materials, softwareschematics)inordertofabricateorbuild the system. Product Baseline The Product (or “As-Built/As-Coded”) baseline represents the approved documentation that represents a configuration as it has been build or coded. The product baseline documents the final configuration of the system as it enters its field deployment and operations phase.
- 43. 16 Prototyping Robotic Systems Configuration Management Process The process of moving from one baseline to an- otheriscontrolledbytheSET.Thisprocessdevel- ops high level requirements into detailed system descriptions and specifications, and ensures that the resultant system meets the high level require- ments. Figure 1 shows the sequence of Systems Engineering phases and their associated output. The first phase of development in systems engineering process is the Requirements Phase, in which high level system requirements are de- rived into detailed functional requirements and system performance measures. The output of this phase is the Functional Baseline. The second phase of development is the Sys- tem Design phase. During this phase detailed system trade-off studies and design analyses are performed in order to produce a design which is feasible and can be delivered under the project constraints (schedule, budget, etc). Major system elements and their interactions are modeled and preliminary estimates of system performance are generatedfromthesystemmodels.Thefirstoutput ofthesystemdesignphaseistheConceptbaseline. Following the development of the Concept baseline, the SET tracks the detailed design and developmentofthesystem.Changestothedesign are requested through a formal Change Request. Change Requests are tracked in the PDM system and are approved by the SETand, if necessary, by PMT.TheSETconsiderseachChangeRequestin light of its impact on the overall requirements. In the event that a Change Request impacts system performance or ability to meet requirements, the SET decides if it is appropriate to request a de- viation from the system requirements or revert a specificconfigurationtotheConceptbaselineand approach the problem in a different way. The System Design phase’s next output is the Design Baseline, which provides all necessary production and ordering information to build one or more complete systems.The design baseline is subject to careful scrutiny and approval by PMT priortohardwareproductionandsoftwarecoding. Followingapproval,productionandsoftwarecod- ing commences. No major changes to the design are permitted at this stage. The final phase of development is the Valida- tionandVerificationphase,inwhichitisconfirmed that the system that has been built and integrated satisfiestheoverallsystemrequirements,andthat all preliminary performance estimates are valid. Adjustments to the system are made in order to suit any variances from the requirements, and the final design is documented and approved as the Product Baseline. Data Management Process File Naming, Numbering and Reuse: A stan- dardized convention for numbering and naming documents is applied to all documents, system components and configuration items such as software. All physical items are provided with unique identification (ID) numbers, as well as a name and description. All ID numbers are to be trackedthroughthePDMsystem.Thisnumbering convention is indentified in a separate document Figure 1. Systems engineering phases and baselines
- 44. 17 Prototyping Robotic Systems which is made available to all involved in the system design process. Components which are identified as inter- changeable (such as standard hardware) are designated the same ID number. Components which are custom fabricated from the same set of drawings are assigned the same ID number with additional information which uniquely identifies each custom component from one another. Enabling Software: The Enterprise Product Data Management (EPDM) enables consistent tracking and approvals of system designs and baselines.TheEPDMsystemprovidessharedsoft- ware tools across the developer organization for: • Product Baseline Automation • Change Analysis • Change Implementation Planning • Change Tracking The basis of EPDM software is the develop- ment of engineering “workflows” which track specific events such as approvals and changes. CASE STUDIES The case studies are prototypes developed by En- gineering Services Inc. (n.d.).Their development cycles followed closely the framework presented in the previous sections. The presentations in this chapterareabbreviatedandonlyfocusonthenew technologies that were part of the methodology described in this chapter. The study cases are also presented in Goldenberg (2007). TRACKER – A Mobile Robot The TRACKER is a mobile robot (Figure 2) with modulartraction,modulararms,modularpayload Figure 2. TRACKER
- 45. 18 Prototyping Robotic Systems interfaces and modular electronics, modular in- terfacesofpayloads,openarchitecturecontroller, and field-programmable Operator Control Unit (OCU).The modular traction provides for the op- tionofusingtracksorwheelsonthesameplatform. The modular arm and modular payload interfaces can be reconfigured for specific missions. The system is used by the military, law enforcement, andciviliansecurityforces,aswellasforpersonal assistance,transportation,andresearchpurposes. Project Management Team: The team was assembled by first appoint- ing a project manager, a person with experience with similar projects, who was also a very quali- fied person in system engineering design. That person became the delegated authority in terms of responsibility and reporting to the executive branch. Then, the project manager assembled the team consisting of: (i) APM – assistant project manager to provide for the day-to-day operations and support to the PM. That person was a junior designer with the ability to undertake project management tasks; and (ii) System Engineer- ing team – consisting of senior project leaders and consisting at least of one representative for each of: system engineering, mechanical design, electronics, software development, production control, QA, and data base system engineering. The project leaders were technically the chief designers, while the system engineer became the chief technologist of the project. Development Process Planning: The PM and System Engineering Team (SET) defined the critical project development path. The major milestones were: Specifications, Design, Critical Design Review, Manufacturing, and Tests. They were scheduled, and budgetary allocations were provided for each phase. Project Control: The PM provided the tools for project management including cost control, scheduling, reporting, and delivery of that infor- mation to the executive branch. System Engineering Specifications See Table 1. Design Base Technology As described in the patents by Lin & Goldenberg (2009, February; 2009, October; 2010, August), the key aspect of the technology is the mobility basedonatrackconfiguration-controllingmecha- nism, using a pair of flippers, each being a 3-bar cam mechanism consisting of 2 moving elements and a cam fixedly mounted on the chassis. The flippers are used to lift TRACKER’s pulleys over stairs or obstacles and adjust the position of its COG to avoid rolling over while ascending and descending. The variable track configuration is provided by controlling the position of the plan- etary wheels using the flipper (Figure 3). The flipper has three functions: (1) to ensure the center of the planetary wheel mounted on the end of the flipper moves along an exactly elliptic path; (2) to provide the tracks with a continu- ously variable spring force for tensioning the tracks; and (3) to change and adjust the center of gravity of the robot system to prevent it from flipping over. The flippers are connected by a central shaft through the center of the chassis and to a pair of special configuration cams mounted on each side of the chassis. The flippers can rotate completely around the shaft. This motion generates variable track configurations. The flippers’ motion shifts the robot’s center of gravity for climbing and descent of obstacles and stairs to maintain stabil- ity as shown in Figure 4. With the variable track geometrycontrolledbytheoperator,andtheability torepositionthesystemcenterofgravity,andalso raise and lower the front or rear of the chassis, it is virtually impossible to get the robot stuck or rolling over on stairs.The ability to reposition the
- 46. 19 Prototyping Robotic Systems Table 1. Specifications Plat- form Ve- hicle size Configurations 1 Basic configuration - Long track with flipper Derivative configuration 1 – Short track without flipper Derivative configuration 2 – Four wheels Height 2 50 cm – 19.7” (planet wheel horizontal) 61 cm – 24.0” (planet wheel vertical) Width 3 54 cm – 21.3” Length 4 93 cm – 36.5” (planet wheel horizontal) 71 cm – 28.0” (planet wheel vertical) Clearance 5 5 cm – 2.0” Weight 6 50 kg – 110 lbs (with payload) Speed 7 On a flat ground: 2.3 m/s – 5.00 mph On a slope: 0.3 m/s – 0.62 mph On a stairway: 0.1 m/s – 0.31 mph Environment 8 All-weather; All-terrain; Weatherproof; Stair climbing 45 deg; Climbing 35cm obstacles; Crossing 50cm gaps; Ability to maneuver over gravel, snow, mud, sand, high grass; Sealed to operate in water at depth of 15cm – 6” Speed of track configuring 9 Planetary wheel: 120 deg/s Number of tracks 10 Two tracks Number of motors 11 3 + Encoders Electronics 12 State-of-the-art micro-controller; abundant in RAM Sensors & mission payload 13 Internal & external temperature sensors, GPS, inclinometer compass, mis- sion payloads Payload 14 40 Kg (88.8lbs) when climbing 45 deg; 300 Kg when not climbing Battery 15 2.5 - 4 hours continuous mission Communication 16 Computer and sensor communication ports RF: Data, 2-way Video, 1-way Audio; COFDM Option Wi-Fi broadcast of video 17 Included Transportation 18 Portable by two persons Manipu- lator Gripper reach 19 Horizontal 120 cm – 47.2”; Option: 180cm with 60cm extension Vertical 170 cm – 67”and Below the chassis 60 cm – 23.6” DOF 20 6DOF: Turret – 300 degree Shoulder 1 – 210 degree Shoulder 2 – 210 degree Elbow – 300 degree Wrist roll – continuous Wrist pitch - continuous Gripper – 10 cm opening Gripper opening 21 10 cm Weight 22 13 Kg – 29 lb; 20 Kg – 44 lb (with extension) Payload lift at full-extension 23 5 kg (horizontal) 10 kg (vertical) Maximum payload lift 24 12.5 kg Payloads 524 Recoilless disrupter, X-ray, Claw, Shock tube initiators, Charge Dropper Assembly, RTVS Mount assembly, Lifting bracket with articulated move- ment for key opening. Tip Speed 26 0 to 12 cm/sec continued on following page
- 47. 20 Prototyping Robotic Systems centerofgravityprovidesadistinctadvantageover competitors in tasks involving ascent and descent of stairs, slopes, obstacles, passing over ditches, and, in general, navigation over uneven terrain. Baseline Configurations TRACKER has three baseline configurations as follows: • Basic configuration: Long track with flip- per (Figure 2a-c) • Derivative configuration 1: Four wheels (Figure 2d-e) • Derivative configuration 2: Short track without flipper (Figure 2f) Thebasicconfigurationhasactiveadaptability by remote control to suit rough and unpredictable terrains, including obstacles and ditches. The ac- tiveterrainadaptabilityofthebasicconfiguration is performed by changing the track configuration using the flippers. The variable configuration is provided by simultaneously controlling the position of the planetary wheels whose location is controlled precisely by a rotating configu- ration-controlling mechanism, i.e. the flipper. For example, surmounting obstacles forward or backward can be realized by rotating the flipper and changing the position of the planetary wheel. Based on the basic configuration, two deriva- tiveconfigurationswithouttheuseofflippers,the short tracks and the four-wheel configurations, respectively, have been developed. High-speed can be easily realized in the wheel mode. The modularity provides TRACKER with high reliability, ease of in-field maintenance and re-configurability. By changing modules, the TRACKERcanbeswitchedfromatrackedmobile robot to a wheeled mobile robot, and this change can be done in the field in just several minutes. Also, any malfunction can be quickly identified, and repair be done by simply replacing the mal- functioning module with a new one. Modular Electronics The electronics of TRACKER are highly distrib- utedandintegratedmodularlywithinthemechani- cal subsystems. The electronics are composed of the following main modules (Figure 5): • Head • Core • Power • Flipper • Flipper transmission • Traction transmission • Arm OCU 1. Weight and Size 27 Light weight 23 Kg Size 54 cm x 40 cm x 30 cm Variable speed joystick control 28 Included Daylight clarity 29 Optimal Battery level indicator 30 Included Weapons firing key 31 Removable lock out key Task space control of arm 32 Included 3D display of tracks and arm configurations 33 Included Table 1. Continued
- 48. 21 Prototyping Robotic Systems Each module is functionally complete and independent. For example, the Power Module includes battery and multiple voltage DC-DC converters, and provides all voltage and power to the entire vehicle electronics. The Core Module includes the main processor and communication system; it manages the communication with the OCU, and controls the motion of the vehicle. Some modules have the electronics and mechani- cal parts integrated, making them fully functional mechatronics modules. For example, the flipper module includes motor, gear head, encoder, an- gular position sensor, brake, servo motor driver, transmissiongearpairs,cam,mechanicalstructure, etc.The arm module includes motors, gear heads, encoders,angularpositionsensors,payloadinter- face,weaponcontrolinterface,andthemechanical structure, links, and gripper fingers integrated. Robot Arms TheTrackerhastwoarms-aModularGripperArm and a Modular PTZ Camera Arm (Figure 2b-c). Theycanbemountedandoperatesimultaneously. Modular Gripper Arm: The Gripper Arm is a modular light weight manipulator. The arm, shown in Figure 6 mounted on the TRACKER, consistsofaturret,shoulderpitchjoint,elbowpitch joint, and specialized wrist-gripper assemblies. The baseline configuration of the Gripper Arm has 4DOF (pitch/pitch/pitch/roll). An optional Figure 3. Schematic diagram of the variable configuration track mobile robot Figure 4. TRACKER climbing stairs
- 49. 22 Prototyping Robotic Systems turret can be added on. The structure of the arm is shown in Figure 7. The features of the Gripper Arm are: • Wrist Roll and Pitch provide continuous rotation • Elbow motor is placed at the base to reduce inertial weight and obtain a light-weight high payload-to-weight ratio arm • Control electronics are placed in the turret to reduce moving parts and weight and for ease of maintenance • All wiring is hidden and protected in the link tubes. This makes the arm look leaner and makes it safer to use • A dedicated 32-bit controller and servo drivers control the arm motion, weapon fir- ing, target aiming, and provide interfaces for the disruptor, relays (power output and contact output), VISCA-based zoom cam- Figure 5. Modules of the TRACKER electronics Figure 6. TRACKER with gripper arm
- 50. 23 Prototyping Robotic Systems era, aiming laser, lights, re-locatable cam- era, etc • Shoulder, elbow, and pitch joints have in- cremental encoders on the motor side and absolute angular position sensors on the output shaft. • Coordinated linear motion of the tip by joystick control is provided. • Pre-programmed motions are provided to facilitate the execution of various tasks. The pre-programmed tasks include homing back to stowed position, raising the arm to a vertical position, extending the arm to a horizontal position, etc. Modular PTZArm: The Tracker PTZ arm is a 1-DOF light weight sub-system for mounting and supporting the PTZ camera. The PTZ arm is suitablefortheSmall,MediumorLargeTrackers, and it consists of PTZ camera, PTZ arm electron- ics box, linear motor, antenna, and connectors. It can be mounted independently on a platform for surveillance, and it can be also mounted on the gripper arm for tactical tasks. The PTZ arm structure is shown in Figure 8. Payload Interfaces The robot provides modular interfaces, data com- munication and power for a range of payloads: sensors, cameras, small tools, and other task and mission accessories. On the Tracker, a typical modular payload interface includes the commu- nication signal, video signal and power supply channels. Interfaces are provided for the firing of the disruptor, aiming the laser, activating relays (for external power supply and contacts), video cameras, the Gripper Arm Module, PTZ Arm Module, Upgrades Module, and standard com- puter interfaces such as USB, Ethernet, RS232, RS485, etc. Operator Control Unit (OCU) A user interface and supervisory controller are provided as the Operator Control Unit (OCU) (Figure 9). The OCU links can be wireless or via fiber optic cable.AHybrid Communication Link (cable-wireless) – an extended communication range through a relay link is also available. The OCUprovidescontrolofarms(GripperandPTZ), theflippers,andtheplatform,aswellascontrolof all payloads of the robot, such as lasers, cameras, Figure 7. TRACKER gripper arm structure
- 51. 24 Prototyping Robotic Systems lights and disrupters. The OCU consist of two parts:(i)control/displayunitthatcontainsalluser control and display interfaces, communication protocol, default configuration, and kinematics calculations; and (ii) RF unit that includes video, audioandcommand/datatransitbetweentheOCU and robot.The user is provided with two methods of controlling the system: (i) buttons/joysticks to control the robot and arm, firing system, relays, parkingandemergencystop;and(ii)touchscreen buttons/joysticks to set the configurations of joy- sticks, cameras, lights and 3D display. OCU Features: • Use of two joysticks that can be reconfig- ured for various control functions • Concurrent video display from different cameras • Display of platform and arm in 3D attitude in real-time • Two-way audio link • Display of battery remaining capacity of both, OCU and robot • Can be powered by either DC or AC pow- er, or by re-chargeable battery • OCU fits in a single portable case OCUSoftwareStructure:TheOCUsoftware runs on a single board computer, with embedded Windows Operating System. The OCU software is composed of a video panel module, 3D panel module, button/joystick module, communication module,andmainbusmodule.TheOCUsoftware package also includes developer tools, such as a debugging module, robot build tool, gripper arm testing tool, PTZ arm testing tool, and commu- nication testing tool. OCUHardwareArchitecture:Thehardware architecture is schematically shown in Figure 10. CommunicationprotocolbetweenOCUand Tracker: To support the open architecture struc- ture and offer access to new payloads through the OCU, the Tracker has a scalable main communi- cation protocol frame between OCU andTracker. In this protocol, information for each payload as a sub-frame is defined, and can be freely inte- grated into the entire communication frame. In case the payload is controlled directly by the OCU, the Tracker communication manager does not need to know the detailed information about the content of the sub-frame. When there is a sub-frame for payload communication, the communicationmanagerjustaddsitintothemain Figure 8. (a) PTZ arm stowed (b) PTZ arm raised
- 52. 25 Prototyping Robotic Systems frame. Also, it sets the address and length of the sub-frame in the main frame to notify the OCU when this information appears. For communication from the OCU to the payload, the situation is similar. If the payload is controlled directly by the OCU, the communica- tion manager detaches the sub-frame from the main frame, and transfers it to the payload com- munication channel. OpenComputerArchitecture(OCA)ofTracker An OCA is necessary for modularity and re- configurability of the system, as well as for wired orwirelesslinkswiththeplatform,arm,tools,and sensors.The open architecture controller consists of an open hardware interface and open software architecture. The open software architecture is composed of open protocol, open instruction sets and open language, library and Application ProgrammingInterface(API)functions.Thenew generation OCA exhibits excellent scalability, extendibility and flexibility. IntheOpenArchitecturetheelectronicssystem providesthevariousstandardinterfacesalongwith necessary power supply: RS232, RS485, USB, and Ethernet. Working with the open software architecture,plugandplaycapabilityisachieved. The open software architecture and the Ethernet application program support this undertaking. The system extendibility with additional physical modules is only limited by the vehicle platform’s physical dimensions and availability of space. In the Open Architecture hardware, an Upgrading module was designed for the large Tracker version to interface with additional sen- sors, payloads and modules. For the Medium and Small Tracker the number of standard interfaces is limited. Theextendibilityisalsolimitedbythesoftware driver, API and libraries. Currently, the Open Architecture and the software are capable of ex- tending a second video RF transmitter including the Wi-Fi devices, and VISCA protocol based on SONY block camera. To be able to accept addi- tional types of sensors and payloads, the software needs to include the related drivers in its library. Figure 9. Tracker OCU
- 53. 26 Prototyping Robotic Systems Manufacturing ModularAssembly:Themodularitycanincrease the productivity, by shortening the delivery time andloweringthelaborcost.Asthemodulescanbe built as inventory, the assembling of the Tracker is quick. The Tracker can be assembled using an “Assembly Line” (Figure 11) manufacturing concept by serially sequencing the modules inte- gration in order to enhance efficiency and reduce the cost of production. Quality Assurance QualityAssurance Implementation Plans (QAIP) were implemented following the internationally accepted methodology for Quality Plans as de- fined in ISO 10005:2005 – Quality Management Systems Guidelines for Quality Plans. The QAIP was managed by project’s Quality Assurance Manager, a consultant brought into the project. The Manager had overall responsibility for the preparationanddisseminationoftheQAIP.Inthis project the QAIP addressed the following areas of QualityAssurance objectives listed in Quality Assurance and Safety Program section. CMDM Configuration Management (CM) provided a means of controlling changes to the design as it Figure 10. OCU hardware architecture
- 54. 27 Prototyping Robotic Systems evolved from a set of objectives into a physical product operating in the field. Data Management (DM) provided a means of electronically storing design data on a file server whichiscapableoftrackingrevisionsandproduct history information. Further, the Data Manage- ment system involved a standardized process by whichdesigndataisbackedupandsecurelystored. The CM plan used described herein is typical and is based upon the CMII-105B Standard for Product Configuration Management by the CMII research institute (www.icmhq.com). AARM - Robot Arm for Internal Operations in Nuclear Reactors It is well known that robotic arms are used to augmentandevenreplacehumanoperatorsinhaz- ardous environments. The AARM is a robot tool for visual-assisted remote controlled inspection and operations inside nuclear reactor cores. The robot is used in Callandria Vessels. The AARM was designed based on standard design methods of robot arms enhanced with proprietary features related to the specific environment, such as colli- sion avoidance and radiation shielding to provide a reliable and safe tool. Roboticmanipulatorshavebeenusedinnuclear reactors for various inspection and service opera- tions as reported by Hamilton et al. (2010), Perrot et al. (2010), Caprari et al. (2010) and Zwicker et al (2010). These references reinforce the notion that designers’experience and customization are the main drivers behind the successes evident in this domain of application. Typically, the range of motion of the robot in a reactor is limited because the base of the arm is normally fixed. Also, the robot must be provided withradiationshielding.Duetothedensenetwork ofpipesinsideatypicalreactor,henceforthlimited access and poor visibility, there is a risk that the robot manipulator would hit internal reactor ele- Figure 11. Modular tracker assembly line
- 55. Another Random Document on Scribd Without Any Related Topics
- 56. CHAPTER XVI IN THE BALANCE Agnes Westbury had listened all the early part of the evening to her husband's enthusiastic plans. Good fortune expanded him in every direction. It was true that quicksilver had been discovered at Alameda, also that the new process of separating gold was a great saving. Working mines had been most extravagant and wasteful. Some of the old ones had been deserted that no doubt would pay again. He had taken options for the London Company, he had two or three for himself. Luck had surely come his way. Now they must leave as soon as possible. Had she enjoyed herself? Had the landlady been satisfactory? Had she gone about and seen much, made any pleasant friends? San Francisco was a strange and wonderful place. It had risen up in a night, as it were. It was in the line of the Eastern trade, it would be the great mart of the world. What was Congress thinking about not to establish a through route, but depend on this miserable overland accommodation for the crowds who would come! Its very wildness and sublimity outdid Europe. Some day it would be a worldwide attraction for tourists. Such mountains, such a range of climate, such a profusion of everything, such a seacoast line. David Westbury was pacing up and down the apartment with a light, springy step. He had been in his youth a tall and rather lanky down- easter. Now he had filled out, was fine and robust, with a good clear
- 57. skin. In those days his nose had been too large, his mouth wide, with rather loose lips. Now the rest of his face had rounded out, his lips had grown firm-set, decisive, and his mustache was trimmed in the latest style. Just at the corners of his mouth his beard had begun to whiten a little, his lightish hair had turned darker. Prosperity had made a man of him. He had grown sharp, far-sighted, but he had an amiability that was more than pleasing—attractive. He had learned to use his own phrase, "not to buck against the world." Where he had been rather credulous and lax in early life, he had become wary and shrewd, and did not hesitate if he could turn the best of the deal his way. "Yes, she had enjoyed herself very much. Mrs. Folsom and her son had been most attentive, there had been some star players at the theatres and a noted singer or two. She had met some nice people, there was a good deal of crudeness and display, but on the whole it was very fair for a new place. And some odd, quaint individuals, some really refined women from Boston, and such a charming young girl that she coveted; she wished she had her for a daughter." "That's a queer wish; too, I thought you were not fond of children." "Well, I am not generally. I'd like them full-grown, and attractive," laughing. "I wouldn't mind a fine, upright, sober, honorable son that one could trust in all things, but they are scarce." "David, what will you do with your money?" "Well,"—he laughed a little. "Let me see—endow a hospital perhaps, or build a college. But we must have all the pleasure we desire." She gave a little sigh. "About this girl, now?" he queried. "She's the dearest, sweetest, simplest body, not foolish, not sentimental, but like water in a ground glass globe, if you can
- 58. understand. She's one of the old settlers, and that's laughable, came in '51, round the Horn, from Maine, I believe, with an uncle and some friends. He is a Mr. Chadsey, and keeps a big warehouse, shipping stores and what not, and is, I believe, making a fortune—to take her journeying round the world." "Chadsey," he said thoughtfully. "Chadsey. What is the girl's name?" "Oh, Chadsey, too." "Ah!" nodding, yet he drew his brows a little. "I suppose he was her mother's brother. Her mother died just before they came out here." He made a brief calculation. "Yes, it was in '51 that she died. And Jason Chadsey was there, he took the little girl away. At Boston all trace was lost, though he had not searched very exhaustively for her. He had a feeling that she would be well cared for." David Westbury glanced at his wife. Her elbow was on the window sill and her cheek rested on her hand. There was a touch of sadness in her face, a longing in her eyes. He loved her more now than when he had married her. She was a little exacting then. She had been very fond of pleasure, theatres, balls, fine dinners at hotels, journeys, dress, jewels. He enjoyed them, too, with the zest that generally comes to one who has been deprived of them in early life, and whose training has been to consider them reprehensible. They had taken their fill. Now his mind was all on business; he liked to surmount difficulties, to bring success out of chaos. He had to leave her alone a good deal. She used to find entertainment in conquering the admiration of young men, but these last few years she had found herself less attractive, except as she listened to their love troubles and begged her for advice. He did not understand this at all, only he felt he had an engrossing business and she had nothing but looking on. "You like this girl very much?"
- 59. "Yes, I can't tell just why, except that she is so honestly sweet, so ready to give of her best without expecting any return. Do you remember Lady Westmere and her two daughters? They were fine girls and devoted to her. I had not considered it much before, but I understood then what an interest and solace a young girl of the right sort would be. You know I had Gladys Wynne to stay a month with me when you were over to Paris. I had half a mind to engage her as a sort of companion, and she would have been glad enough to come. But I found she had some mean, underhand tricks, and was looking out for her own advantage while she was trying to persuade you that it was yours. And she told little fibs. So I gave up the idea. A maid, you know, is no company, though one must have her abroad. But we couldn't coax or kidnap this girl," and she sighed in the midst of a sad smile. He still paced up and down. How long since he had thought of that old life. He had always said to himself that he had been a fool to marry Laverne Dallas, but he had taken a good deal of satisfaction then in "cutting out" Jason Chadsey. What fools young fellows were! "Agnes," he began, "before I married you I did not tell you my whole story. I said I had lost my wife and child, that ill luck had dragged me through those early years. She had another lover, Jason Chadsey, a seafaring man, of whom she had not heard in a long time, when she married me. Some years later I was at a low ebb and away, trying to make money for them as well as myself. When I had a little success I went back. She was dead and buried. Chadsey had come back, it seems, and taken the child, since there were no near relatives to say him nay. At Boston I lost trace of them." "Oh, David!" She sprang up and flung both arms about him. "You don't think—this Laverne—why, what if she should be yours!" "She came here late in '51. Her mother died early in the spring before. She must have been about eight. Why, it's quite a romance for this prosaic world."
- 60. "If you are her father, you have the best right. Oh, David, I should love her and be so good to her. She should have everything, and I would be so happy. Oh, you must see to-morrow." There was a hysterical catch in her voice, and a great throb at her heart. "There, don't get into a fit. Why, I didn't suppose you could care so much. Yes, I know you will be good to her. Chadsey may kick about giving her up, but I doubt if he took any steps toward legal adoption. Oh, I think there will not be any real trouble unless she will not come." "But she ought to have some regard for her father! And he isn't really her uncle or guardian. Why, it wouldn't be quite the thing for her to travel round the world with him." They talked it over until their plans seemed most reasonable. And then they wondered at the strangeness of it. He had no real compunctions of conscience about the past, though of course he would have accepted the responsibility of his daughter if he could have found her. He had a practical business way of looking at matters. And while Agnes Westbury lay awake, and had vague visions, dropping now and then into snatches of dreams, he slept soundly and awoke with a resolve to settle the question with just the same purpose as if he had resolved to buy his wife thousands of dollars' worth of jewels. They had begun the necessary sea wall that was to safeguard the piers and the shipping that grew more extensive every year. Here was the old Fisherman's Pier, then steamers, trading vessels, queer foreign ships, business places of all sorts, many of them quite dilapidated, fringed East Street. Here, where Clay Street ran down, almost meeting Sacramento, there were warehouses, packing houses, boxes and bales and general confusion. The one-story place with the sign "J. Chadsey" over the wide doorway, not much handsomer than that of a barn, but strengthened with iron bars and
- 61. great bolts, had stretched out and out, and now they were packing in stores from the Orient, stores from the Isthmus, that were being unloaded from two vessels. Jason Chadsey had been giving orders here and there, setting men at work, and was warm and tired when word came that a gentleman wanted to see him in the office. They made distinctions in those days, even if the country was new and rough. That was no strange summons. He pulled out his handkerchief, and wiped the sweat and grime from his face, listened a moment to the wrangling, swearing, strange Chinese chatter, songs in various languages, then turned and went in, hardly able to see at first from the glitter of the sun that had drenched him. This was a place just now with two big desks and a clerk writing at one. The inner office had a window on the street side and two wooden stools, one dilapidated leathern chair before another desk. A man rose up and faced him. A well-dressed, well-kept man, with a certain air of prosperity and authority, and if he had any scheme to exploit it would no doubt have some advantage in it. But he was a stranger. "You are Jason Chadsey?" Westbury would have known him anywhere. Except to grow older, to be a little more wrinkled,— weatherbeaten, he had always been,—and his hair slightly grizzled at the temples, he was the same. There was honesty, truth, and goodness in the face that had not changed either. "Yes," Chadsey replied briefly. "And you don't remember me?" Chadsey tried to consider the voice, but that had grown rounder, fuller, and lost all the Maine twang. There had been so many faces between youth and this time. "Well, I am David Westbury."
- 62. Jason Chadsey dropped on a stool and stared, then mopped his face again, while a shiver passed over him that seemed to wring his very vitals, turn him stone-cold. "It's odd how things come about." The man of the world had his rival at a disadvantage. "I'd had runs of hard luck," in an easy, almost indifferent tone, being where he could laugh at the past, "and I'd tried about everything in vain. I was too proud to come back to Laverne empty-handed. Then, when I had made something, I turned, hoping to ease up her hard life, and found she was dead and buried. You had befriended her; thank you for that. But you took my child. I traced you to Boston. After that my search was vain. I have looked over lists of vessels, thinking to strike your name as captain or mate, and finally given up search. Business brought me here, perhaps fate, too, had a hand in it. My wife has seen and known the child, and already loves her. I am grateful for your care all these years, but I would rather have had her in my keeping. I am a rich man—if I was a poor devil I would put in no claim, no matter how dear she was to me, but a father has the best right." Jason Chadsey rose. For a moment he had murder in his heart. The man's evident prosperity and effrontery stung him so. The past came rushing over him. "Do you know how I found her?" he began hoarsely. "I had resolved to come out here. I was getting tired of seafaring. I went to Munro to say good-by to a few old friends. I expected to find her a happy wife and mother, with little ones about her. Instead it was a virtually deserted wife, who had heard nothing of her husband in a long while, who had used up all her little store and was in debt besides, who was suffering from cold, want, heartbreak, and dying, knowing no refuge for her child except the poor farm or to be bound out to some neighbor." "No, she would not have been," was the almost fierce interruption.
- 63. "The dying woman did not know that. She had some comfort in her last moments," and his voice softened curiously with remembered pathos. "She gave me the child. I have been father and mother to her. You cannot have her." "I believe the law gives the parent the right to the child until she is of age. You had no consent of mine. You could not legally adopt her, at least, it would not hold in law." Jason Chadsey turned pale under the tan of years. Why, he had not even thought of any legal protection for his claim. It rested only on love and care. "You see," continued the confident voice, "that my right has been in no way jeopardized. I am Laverne Westbury's father, amply able to care for her in an attractive and refined manner, place her in the best society, to give her whatever education and accomplishment she needs, the protection of a mother, the standing of a father, travel—we are to go to England shortly—and it would be worse than folly to stand in her way." "She will not go," Jason Chadsey said sturdily. "She will if the law directs." "She will not when she knows the struggle of the last year of her mother's life. Why, you robbed her mother, the poor, old, helpless woman, of the little she had. You persuaded her to take up money on the house—it was not worth much, but it was a home to shelter them." "Laverne was as anxious to get out of the place as I. What could I do there? She was willing that I should try. I was unfortunate. Other men have been—you find wrecks everywhere. I struggled hard to recover, and did, even if it was too late for her. We thank Providence for our successes—doesn't the same power direct reverses? It wasn't my fault. Luck runs against a man his whole life sometimes."
- 64. "You could have written. That would have cheered her solitary hours. She would have told you she was dying, and begged you to come. When I think of what that dreary winter was to her——" "You were there to comfort her." There was a half sneer on the face. "See here, Jason Chadsey, you were her first lover, not a very ardent one, I fancy, either. I was a fool to persuade her to marry me, though I think her grandmother had a strong hand in it. You were there those last weeks. Did she confess her mistake, and admit that you had held her heart all these years? What confidences took place?" "None that you might not hear. Nothing but some truths that I guessed, and wrung out of her—your neglect. You would not dare to stain the mother's memory to the child. If you did I think I could kill you. Any one who knows aught about those New England women, brought up among the snowy hills like nuns, would know it was a base lie!" "Come, come, we won't slop over into melodrama. We will leave it to the law if you agree to abide by the decision." "The law will not force her to go." "I think she will be convinced. You are no kin to her. Now that she is grown, it is hardly the thing for her to go on living in this fashion. You may mean to marry her. That would be monstrous!" "Go your way, go your way, David Westbury," and he made an indignant gesture as if he would sweep him out of the place. "I have other matters on hand. I have no time to parley." Then Chadsey turned and, being near the door, made a rush for the street, plunging the next minute into the thick of business. Westbury laughed a moment, lighted a cigar, and sauntered out at his leisure. Up in a more respectable street he glanced about, finding a lawyer's office, and though he guessed the opinion must be in his favor he wanted an assurance.
- 65. "If there had been an assignment under belief that the father was dead, he could recover, if it was proved he was the proper person to have the care of the child, and amply able to support it." Jason Chadsey worked furiously. He would not think. It was high noon before he found a respite. Then he went in the office instead of going to lunch. He could not eat. The shadow that would hang over him now and then, that he had always managed to drive away, had culminated at length in a storm that would sweep from its moorings the dearest thing he held on earth, that he had toiled for, that he had loved with the tenderness of a strong, true heart, that had been all his life. Without her it would only be a breathing shell of a body, inert, with no hope, no real feeling. Ah, if they had been ready to go away a few months ago! If Laverne was of age! If he had a legal adoption, they might make a fight on that. He had nothing. But she would not go, she would not go. Ah, how could he tell her? Perhaps her father and yes, that soft- spoken, insinuating woman, was her stepmother, and Laverne had a young girl's fancy for her—perhaps they would go and lay the case before her, persuade, entreat—oh, no, they could not win, he felt sure of that. How could he ever go home! What would the home be without her! What would life be—the money—anything! It was quite late when he climbed the ascent, growing worse and worse. There had been two landslides. Why, presently they would be swept away. "Oh, how late you are!" cried the soft, girlish voice. "How did you get up? Isn't it dreadful! Have you had a hard day? Was there a steamer in? Do you suppose we shall ever have a letter from the Hudsons?" Nothing had happened. Perhaps David Westbury did not dare. He almost crushed the slim figure in his arms.
- 66. "Oh, what a bear hug!" she cried, when she could get her breath. "And you are so late. We had such a splendid big fish that Pablo caught and cooked, and it was delicious. And I made a berry cake, but you like that cold, and we will have the fish heated up. Was it an awful busy day?" "Yes, a vessel in, and another to be loaded up." His voice shook a little. "Oh, you dear old darling, you are tired to death. Here's a cup of nice tea. And if you were a young lover, I would sing you the daintiest little Spanish song. Isola and I made it up. You see, things don't sound quite so bare and bald in Spanish, and you can make the rhymes easier. The music is all hers. We are supposed to sing it to some one gone on a journey that we want back with us." "Well, I'm an old lover; sing it to me!" Then she would not notice that he was not eating much supper. The guitar had a blue ribbon, and she threw it over her shoulder and shook her golden hair about. Tinkle, tinkle, went the soft accompaniment. She had a sweet parlor voice, with some sad notes in it, wistful, longing notes. He wondered if she was thinking of any one miles and miles across the water. "It is tender and beautiful," he said, "sing something else." "You are not eating your cake." "But I shall." He must choke down a little. Afterward they strolled about the hill. There was no moon, but the stars were like great golden and silver globes, and the air was sweet with a hundred fragrances. Nothing had happened, and he wondered a little at it. Suddenly she said: "Oh, you must go to bed after such a hard day's work. And I am cruel dragging you about."
- 67. He could not tell her. Oh, what if he should never need to tell her! How could he give her up? Was life all sacrifice? Something odd had happened to her. She sat by the window living it over. She had gone around by Folsom House to see Mrs. Westbury, thinking how she should miss her when they went back to England. She ran up to her room. There was a thin lace drapery in the doorway to bring a breeze through and yet shield the occupant from the passer-by. "Oh, you sweet little darling! Did you dream that I was wishing for you? I've been just crazy to see you all day." She was in a dainty white silk négligée, with cascades of lace and some pale pink bows. She wore such pretty gowns, Laverne thought. "Do you know that in about a week we shall go away? And I shan't know how to live without you. I love you so! Why do you suppose I should be always longing for you, thinking about you? Last night ——" She gave her a rapturous embrace and kissed lips and brow and eyelids. Sometimes Isola Savedra caressed her this way. But Isola was just a girl, musical, vehement, Spanish. "I couldn't sleep for thinking of you, longing for you. Shall I steal you and take you away? Oh, if you loved me well enough to come, you should have everything heart could desire. I am so lonesome at times." "I shouldn't come for the things," she returned, coloring. "And if I loved you ever so much——" "No, don't say you wouldn't. Oh, to-morrow I shall have something strange to tell you, but now I say over and over again I want you, I want you!" Laverne drew a long breath. She was half magnetized by the intensity, by the strange expression in the face, the eager eyes.
- 68. "I shall be sorry to have you go." She hardly knew what to say. Sorrow did not half express it. "Don't mind me—yes, it is true, too. But I heard a story last night that suggested such a splendid possibility. I couldn't sleep. And I can't tell you just yet, but when you hear it—oh, you'll be tender and not break my heart that is so set upon it. Something you can do for me." "I will do anything in my power." "Remember that when I ask you." She was fain to keep her longer, but Laverne had a curious feeling that she could not understand, a half fear or mystery. And then she had some translation to make for to-morrow. She was studying German now. She worked steadily at her lessons. Then she had a race with Bruno, and waited out on the steps for Uncle Jason. What would happen to her to-morrow? It might be an elegant parting gift. How strange Mrs. Westbury had been. No one had influenced her in just that way before. Then she went to bed and fell asleep with the ease of healthy youth. Jason Chadsey tossed and tumbled. What would to-morrow bring? How would Laverne take it? Must she go? Would she go? How could he endure it? "One," the solemn old clock downstairs said. "Two." He had half a mind to get up. Hark, what was that? Or was he dreaming? Oh, again, now a clang sharp enough to arouse any one. Fire! Fire! He sprang out of bed and went to the window. Was it down there on the bay? He stood paralyzed while the clamor grew louder, and flames shot up in great spires, yellow-red against the blue sky. And now an immense sheet that seemed to blot out the middle of the bay, as if it could run across. "Clang, clang," went the bells. "Oh, what is it, fire?" cried Miss Holmes.
- 69. "Fire down on the docks. I must go. Do not disturb Laverne." Let her sleep now. She would know sorrow soon enough. He dressed hurriedly and went out. The stars were still shining in the blue sky, though round the edges toward the eastward there were faint touches of grayish white. But the zenith seemed aflame. Up went the great spires grandly, a thing to be admired if it brought no loss. He went stumbling down the rough ways in the semi-darkness. Once a stone rolled and he fell. Then he hurried on. Other people were out—you could discern windows crowded with heads. Was San Francisco to have another holocaust? There were shrieks and cries. The noise of the engines, blowing of horns, whistles, boats steaming up, others being towed out in the bay, wooden buildings hastily demolished to stay the progress of the red fiend. Crowds upon crowds, as if the sight were a new one. On the corner of Davis Street he sat down on a barrel, close by a stoop, overwhelmed by the certainty. Why go any nearer? The rigging of a vessel had caught, the flames twisted this way and that by their own force, as there was no wind, fortunately. All the labor of years was swallowed up, her fortune, her luxuries, her pleasures. Another twelve months and it would have been secured. But, alas! she would not be here to share it. Did it matter so very much? His soul within him was numb. Since he had lost her, what need he care for a prosperity she could not share? The hot air swept his face. Pandemonium sounded in his ears. Men ran to and fro, but he sat there in a kind of dumb despair that all his life should have gone for nought, labor, and love as well.
- 70. CHAPTER XVII THE DECISION OF FATE Pablo told them the heart-breaking news. But about eight o'clock Uncle Jason returned. The fire was out, there were only heaps of smoking ashes and smouldering brands. Jason Chadsey had been warmly sympathized with, proffered assistance to rebuild, to recommence business, and would have been deluged with whiskey if he had accepted. That was still a panacea for all ills and troubles. But he refused, and wandered about in dogged silence. No one knew the whole loss. In the farther office desk he had slipped a box with a string of pearls for his darling's birthday. Some one had said pearls were for blondes, and in spite of much out-of-door living, she had kept her beautiful complexion. Then crushed by the astounding news, he had forgotten about it. "Oh, Uncle Jason!" Grimed as he was with smoke and cinders, she flew to his arms, and sobbed out her sorrow. "There, there, dear." His voice had the stress of fatigue and great emotion. "I am not fit to touch. And I can't talk now. I am tired to death. Give me a cup of coffee." "I don't believe I will go to school to-day," she said, with fine disregard of rules. "And yet I ought. There are the translations to be handed in."
- 71. "Yes, do go. I must get some rest." "I'll come home at noon," kissing him fondly. He nodded. He was a broken old man in what should have been the prime of life. He drank his coffee, then took the whiskey he had refused down on the dock, went to his room, and after a good cool wash, threw himself on the bed. The fire was on everybody's tongue. Not that fires were a rarity. But this might have been much worse, yet it was bad enough for Jason Chadsey. The air was still full of smoke, there was a dense fog and a cloudy sky. Everywhere you heard the same talk. The lessons at school went on well enough, though Laverne's nerves were all of a tremble. Just after eleven as recess began she was summoned to the reception room. David Westbury had been out to the fire and come in again. "Gad!" he exclaimed. "It's that Chadsey's place! And he had a tremendous stock, a new shipload just in, some others waiting to be loaded up. This is a queer town where every so often there's a big fire. The only amends is that it is rebuilt better. Half of the old rookeries ought to come down, they look so forlorn and ancient." "Oh, David. Well, if he has lost everything he will be the more willing to give up the girl." "He will give her up, anyhow," in a determined tone. Some things Chadsey had said still rankled in David Westbury's mind. He went downtown again. Yes, it was ruin sure enough. Being prosperous now, he could afford to pity the unfortunate ones. Chadsey had gone home. The police were in charge, to keep off the roughs and the thieves. "We must have the matter settled to-day," he declared to his wife. "I know where she is at school. Let us go there."
- 72. "Excellent. I should like to see her alone. It is right that she should hear my story." So to the school they went. Laverne came in a little flurried, and yet bewitching in her simple girlhood. Her bodice was rather low about the throat, with some edging around, and a band of black velvet encircled her white neck. Her skirt was ankle length, and the man noted her trim, slender feet, with the high arch of the instep. Mrs. Westbury kissed her with warmth and tenderness. Her eyes were luminous this morning, and the flushes showed above the delicately tinted cheeks; her whole air was pleading, enchanting. "You know I said there was a strange story for you to hear," she exclaimed, when they had talked at length about the fire. "Mr. Westbury will tell you." He began to pace up and down, as was his habit, so slowly that it gave him an air of thoughtfulness. Mrs. Westbury had her arm around Laverne. "Yes, a rather curious story, yet numbers of these instances crop out along life. Friends, often relatives are reunited, tangled threads are straightened, mysteries explained. In a little village in Maine lived a girl and her two friends, they were a little too old for real schoolmates. Her name was Laverne Dallas." Why, that was her mother's name. And Maine. She began to listen attentively, just as one pieces out a dream that has nearly escaped from memory. And Westbury! Why, she had forgotten she ever had any other name than Chadsey—it was her story as well, and now she looked at the man, who certainly had nothing repellant about him, and the story of those early years was pathetic as he lent it several appealing embellishments. She really could not remember him with any distinctness. The death of her grandmother, the pale, reserved mother, coughing and holding on to her side, the coming of Uncle Jason, who it seemed was no uncle at all, her mother's death, and all the rest was school and play.
- 73. "Oh! Oh!" she cried, and hid her face on Mrs. Westbury's shoulder. "So you see you are my little daughter. Your own mother is not here to care for you and make you happy, but here is a new mother, who has learned to love you unaware. And now we are returning to London, and will take you with us, and give you the life that rightly belongs to you——" "Oh, no, no," she interrupted with poignant pathos. "I cannot go. I could not leave Uncle Jason in this sad loss and trouble. He has been so good, so kind, so tender——" "As if an own father could not be that! Laverne, my darling, my own little girl!" If he had been poor he would have thought any child a great burden. He was not the sort of man to make sacrifices for any one. They would have irked him terribly. But in prosperity he was very indulgent. There are many such people. Jason Chadsey would have shared his last dollar, his last crust, ungrudgingly. They began to set the matter before her in a reasonable, practical light. Henceforward she would be a burden on Mr. Chadsey, who had already done so much for her. She would have in her parents' care accomplishments, travel, society, a lovely home, pleasures of all kinds, and now she was old enough to enjoy them. And they wanted her. Her father had the lawful right, would have until she was of age. "I must go home," she said at length. "It is so strange. I must think it over. And if Uncle Jason wants me——" "And we want you." Agnes Westbury gave her a tender embrace, as she wiped the tears from her own eyes. They could not be allowed to run riot down the cheeks as Laverne's were doing. She rose unsteadily. "Have you no word for me, your father?"
- 74. She went to the outstretched arms and hid her face on his breast. She could not love all at once. She could not break Uncle Jason's heart. "I know it must seem strange, but I think Mr. Chadsey will recognize my right in you. We must see him——" "To-morrow, then," she interrupted. "Let me have this afternoon to consider, to talk." Her voice trembled from exhaustion. She took a few unsteady steps. The noon bells began to ring, and again she said she must go. They importuned her to accompany them to the Folsom House to dinner, but she would not consent. Then her father insisted that she should have a hack, but she refused that strenuously. They walked together some distance. "Arrangements must be made to-morrow morning," her father said authoritatively. She felt as if she had been metamorphosed into some other person. Laverne Westbury! it made her shiver. She liked the old personality so much better. Must she go away? This was all the real home she had ever known, this strange, odd, ever-changing Old San Francisco. Why, over here there was a row of tents when they first came. And the queer little one-room and two-room adobe houses, and the tangled-up streets that ended at some one's house. How plainly she could see it all! She began to climb the hill wearily. Then some one came to meet her, helped her tenderly over the rough places. They did not pause at the house, but took the winding path up to the pine tree that grew more beautiful every year, with its shining needles and gray- green, fuzzy buds, almost like little kittens rolling and tumbling in the wind. Balder the beautiful was resting here. Here Victor had really said good-by to her. Why, Victor was in London. And suddenly London seemed to emerge from the gloom of the Tower, and the execution of King Charles and a hundred other melancholy reminiscences.
- 75. "Laverne!" her uncle began. "Oh, I know! I know! They both came to school. They told me everything. But I shall not go. Do you think I could be so ungrateful, so heartless now in all this trouble? And I love you. It is years of love between us, and only a few weeks with them. Oh, no, no!" There was a long silence. A vireo came and sang his merry lilt in the tree overhead. The fog and a good deal of the smoke had cleared away, and the sun was shining. He was very glad of the love. It would comfort him all the rest of the weary way. "Listen, child," he said at length, and he went carefully over the ground. The strongest point of all was that the law would give her to her father the next four years. And now he would have to start in anew and make another fortune. "I am not too old," he declared, with a little pride. A word had caught her, just as one catches a ball with a chain at careless throw. "Four years," she said. "Why, then when I am twenty-one I could come back. Four years only! Will you be waiting for me? I shall surely come." She would be married before that. A pretty young girl with a fortune was not likely to be left on the bush. He caught at it, too. It would smooth the way since the parting had to be. He had nothing; Westbury had it all. "Oh," she cried impulsively, "I can think how you loved my mother. Was she happy there at the last with you? But you two should have been married, and I should have been your child. Why do things, wishes, events go at cross-purposes?" Alas! no one could tell. It was one of the great world's mysteries.
- 76. Miss Holmes summoned them to dinner presently. She had heard the story, and though it was hard, they had to admit that the child belonged to her father while she was under age. Half the night Laverne thought she would defy them all and stay. Would her father want to drag her away a prisoner? What was a father's love like? Wasn't the playing at it better and holier; the sense of loss somewhere else making it diviner, giving it a yearning that a full right could never quite embody? She did not like the full right to be taken, she would rather be coaxed a little and led along. And she could not positively decide about Mrs. Westbury. Some girls she found were quite extravagant in their protestations and then forgot. Olive was one; there was another very sweet girl in school who wanted always to be caressing the one she liked. Isola was not always demonstrative. They did have some delightful quiet times. Were not women girls grown larger and older? It was strange, Laverne thought, how nearly every one was ranged on Mr. Westbury's side. The Personettes admired him, Mrs. Folsom considered him a gentleman, and at that time the term was a compliment. The schoolgirls envied her the romance and the going abroad. Even Miss Holmes thought it the right and proper thing to do. Uncle Jason did not discuss the right, with him there was nothing else to do. Other matters troubled him. Property had been queerly held in the city. There had been squatters, there had been old Mexican deeds, claims coming up every now and then to be settled with difficulty. Jason Chadsey had leased the ground and the waterfront when it had not been very valuable. He had bought one building, erected others. In a year more the lease would expire. Already large prices had been offered for it. He could not rebuild, though generous friends had proffered him any amount of money. He felt unable to take the stir and struggle for no end, that he could not explain. Like a wounded animal, he wanted to go off in quiet and seclusion and nurse his hurts. He had been worsted everywhere, let him give up.
- 77. Mrs. Westbury had wisdom enough not to make her claim at all onerous. There would be plenty of time on the long journey. Every day her old friends seemed dearer to Laverne. At Oaklands they bewailed the separation, but recognized its rightfulness, its necessity. To Isola it was a joy that she would see Victor, and she sent no end of messages. Mrs. Savedra said to Miss Holmes, "If you desire to make a change, we shall be more than glad to have you." David Westbury drove his wife and pretty daughter about with a proud, satisfied air. Agnes shopped for her, "just enough to make her presentable," she said when Laverne protested. But, after all, the parting was very hard. "You must not come and see me off, Uncle Jason." She could not renounce the dear, familiar name. "If you did, I should give one wild leap and land on the wharf, and you would have to keep me. Four years—it's a long, long while, and there will be room for a great many heartaches in it, but one day they will be healed." He obeyed her, and did not come. There were many friends who did. So she went sailing out of the Golden Gate on as fair a day as she had first entered it. Oh, how the sun shone and tipped the waves with molten gold. Never were skies bluer. Even the rocks, and the clefts, and the crannies brought out their indescribable colors, browns that deepened through every shade into purple and black, grays that were pink and mauve and dun, blues that ran into sapphire, and green and chrysoprase. Telegraph Hill and the old, time-worn semaphore. Oh, farewell, farewell, dear old San Francisco! There was some trouble getting insurance matters straightened up and paying debts. Jason Chadsey had lost the spring of ambition and life. He would take a voyage up north with some of the explorers, then he would think of the next thing. Four years. Oh, no, she would never return. The bright, laughing, gay world would swallow her up.
- 78. Marian Holmes pitied the man profoundly through this time. They had been excellent, sensible friends. There had been two or three occasions when she would have married him if he had been really in love with her. She knew now why his love-day had passed. She enjoyed her own life, her own neat ways, her liberty. She and Miss Gaines were still very warm friends, and the latter would have liked her to come with her. "I have a fancy to try it at Oaklands, and help Americanize these charming people, perhaps spoil them. It will be very easy and delightful. The daughter will be a rather curious study. If she were poor, she would have a fortune in her voice. She has quite a gift of poetry. I shall try to keep her from morbidness and a convent, now that she has lost her friend. And her mother wants her fitted for marriage. How these foreigners harp on that!" laughing a little. Laverne Westbury cried herself to sleep many a night, though in the daytime she took a warm interest in all about her, and tried to be agreeable, tried to draw near to her father. He was proud of her prettiness, of her refined ways, the delicacy that had come down to her from the New England strain. It was English, and she would "take" over there. Then he was glad to have Agnes so happy. It was like a girl with her first doll. Often Laverne would rather have been left alone, but she tried not to be ungracious. They crossed the Isthmus, quite a new experience. They went up to Washington, where David Westbury had an excellent scheme to exploit that did get taken up afterward. Then to Liverpool. The little girl never dreamed there would come a time when one could cross the continent in a week, the ocean in another, and her father's expectations seemed quite wild to her. There was a visit over to Paris. Eugénie was at the height of her popularity, but now she had to take a little pains with her beauty. Still she was the mother of a future Emperor, she was a favorite daughter of the Church, she set the fashions and the manners of the day and did it most admirably.
- 79. It was not possible for a girl to be unhappy or cry herself to sleep amid such charming surroundings. Her French was very useful, she had been so in the habit of using it at home that she did not take it up awkwardly. Then they must go to London and get settled. They would have a real home, an attractive place where they could entertain. Mr. Westbury would be away a good deal on flying trips, and now he would not mind leaving his wife with her pleasant companion. He really grew fond of Laverne in a proud sort of way. He liked women to have attractions. He was not jealous, he had found his wife too useful to spoil it by any petty captiousness. Laverne was really amazed. A simple little home, Mrs. Westbury had said, but it seemed to her quite grand. A pretty court, the house standing back a little, a plot of flowers and some vines, a spacious hall with rooms on both sides, a large drawing room, smaller delightful apartments, sleeping and dressing rooms upstairs, a man and several maids, and a carriage kept on livery. On one side of the hall were an office and a smoking room devoted to the gentlemen who called on business, and there were many of them, but they did not disturb the ladies. Some old friends came to welcome Mrs. Westbury back, and this was Miss Westbury, who had been at school in the "States" while they were travelling about, and now would remain permanently with them. Mrs. Westbury sent out cards for a Sunday reception and presented her daughter to the guests. She was something delightfully fresh and new, a pretty, modest girl who might have been reared in any English family, and who was not handsome enough to shine down the daughters of other mammas. It was her very naturalness that proved her greatest charm. And Mrs. Westbury found she had not made any mistake in desiring her. Young men sought her favor again. Older men lingered for a bit of
- 80. bright talk. Laverne felt at times as if she were in an enchanted world. How could youth remain blind to the delight? Then all the wonderful journeys about to famous places, art galleries, concerts, drives in the parks. It seemed as if there was no end to the money. Since prosperity had dawned upon David Westbury he had made it a rule never to want twice for a thing be it indulgence of any reasonable sort, once when he had, and once when he had not. His plans were working admirably. A golden stream was pouring in and he was in his element. A few years of this and he could retire on his competency. She wrote to Miss Holmes and heard from her the current news about every one. Olive Personette was well married. Isola had a music master, an enthusiastic German, who insisted such a voice should not be hidden out of sight and hearing. Her father had been persuaded to allow her to sing in St. Mary's Church, recently completed in a very fine manner, on Ascension Sunday and there had been great enthusiasm over the unknown singer. Elena was growing up into a bright, eager girl who rode magnificently and danced to perfection, and was already drawing crowds of admirers, much to her mother's satisfaction, and would make amends for Isola's diffidence and distaste of society. Dick Folsom was still flirting with pretty girls. Nothing had been heard from Mr. Chadsey, except that he had gone up to the wild Russian possessions. There was inclosed a letter from Mrs. Hudson, who was a happy mother, and José was the best of husbands. Laverne wondered at times how it was possible to hear anything of Victor Savedra. Girls were so hedged about here, everything they did inquired into. It would not be proper for her to write, and if she had an answer Mrs. Westbury would know it. She kept an excellent watch over her pretty daughter. She was really glad no one heard from Jason Chadsey. In this round of pleasure Laverne would soon forget that crude life, and not care to go back to it.
- 81. She did find many things to interest. But the Westbury society was not of the intellectual type. Then there were no stirring questions about one's own town. London seemed a great agglomeration of small places, and was to a degree finished. There was no especial Steamer day, there was no influx of miners, no great bay with its shipping at hand, and, oh, no great ocean with its multitude of denizens to watch. Yet, of course, there were other wonderful things, the galleries, with their pictures and statues, only it seemed to her that people went quite as much to see each other's fine clothes. There were the churches, the palaces, the great piles of learning that had trained Englishmen hundreds of years. Mr. Westbury took them to the House of Commons to a debate that he was interested in, but she felt a little disappointed. Somewhere at Oxford was Victor Savedra, but what was one amid the great multitude? They went over on the French coast for a summering and Laverne found herself quite a favorite at once. She was so modest and unassuming. American tourists had not invaded every corner of Europe. And a young American who knew French and Spanish people at home, where no one supposed they could be found, where they looked only for wild Indians, was indeed an unusual personage. Mrs. Westbury was proud of her stepdaughter. She was so tractable, it was so easy to keep her out of the reach of undesirable admirers. Indeed, she thought she should be jealous when Laverne came to have lovers. Then back to London again, visiting at country houses where there were hunts and much fine riding, pretty evening balls, queer old women, titled and bejewelled, to whom every one seemed to bow. And it was while they were at Thorley that Lord Wrexford came home from the Continent, where he had been trying to live cheaply for a while. He was five and thirty, very well looking and agreeable, and though he had taken on some flesh he was not too stout for
- 82. dancing, so he was invited out considerably, though he was not esteemed a catch in the matrimonial market. For it was well known that Wrexford Grange was nearly covered with mortgages. The old lord was helpless from paralysis, not able to sign his name, and too infirm in mind to consent lawfully to any measures looking to the disposal of the old place. Indeed, his death was looked for almost any time. He came with a purpose beside dancing. A friend had said: "See if Westbury can't do something for you, or put you in a way to help yourself. He has some companies under way that are simply coining money." "Why, I thought he went to America." "He did and has been back a year perhaps. Lord Elsden is in one company. It has something to do with quicksilver, and there's a gold mine. You used to be quite cronies." "Yes, he was a good fellow. He helped me out of one difficulty." So he went to Thorley Wold not only to dance, but the day after the ball he took David Westbury over to Wrexford Grange and they went through papers and debts, some to the Jews that had been ruinous and were now pressing. "You see," the younger man said, "if I stood alone I should let the place go. You must know of chances to make money out there in the new countries. I'd start off to-morrow if I could, and hunt up a gold mine." "They are not always to be found," smiling with a touch of shrewdness. "And mining isn't just the thing for——" "A scion of nobility. What did I read the other day?—some lucky fellow unearthed a nugget worth thousands." "Yes—that does happen," nodding rather incredulously. "Well, if you want me to, I will take these papers to London with me and see
- 83. what I can do for you. It's a fine old estate." "And nothing to keep it on. Oh, I shall get out of it fast enough when the poor old Governor is gone. It's a good thing he's past worrying over it, or knowing it, for that matter." So they returned to Thorley in time for dinner, and in the small dance that evening among the house guests, he took Laverne Westbury out twice, and heard part of her story. Mrs. Westbury did not think particularly of the matter until Lord Wrexford had been at the house several times and paid her some marked attention, invited her and her daughter to visit Grosvenor Gallery and see an especially handsome portrait, the work of a friend of his who was coming rapidly up to fame. "The fur on her wrap is so beautifully done that it seems as if you might blow it about with a breath. And she is an extremely handsome woman, was one of the court beauties a few years ago." Mrs. Westbury was very much pleased with her escort. A title did go some distance in her favor, though she never made any vulgar snatch at it. "What about that Lord Wrexford?" she asked of her husband one of the evenings they happened to be alone. He looked up from the stock list he was going over. "The man or the estate?" with a short, rather brusque laugh. "Well—both." Her smile might have been that of an arch conspirator. A sudden thought occurred to him. There were many business proffers made to him in these days. "He's trying to stave off some business until his father has gone. He was willing to cut off the entail, but the question arose as to whether his father was capable, and the lawyers declare he is not. Some parties are to bring suit unless certain claims are met. The
- 84. indebtedness is enough to swallow up the whole thing. A fine old estate, too." "It is a pity the title cannot go with it," she remarked longingly, with a meaning look. "The young man can," and he laughed. "I wonder some one hasn't——" and she made a suggestive pause. "He might marry the daughter of a rich tradesman, I suppose. He is really a better class fellow, and would shrink from a lot of vulgar relations. Most of these Commoners have such large families, and the other class seldom have fortunes for their daughters. The Jews will get the estate in the end, I think, and I am really sorry for him." "And he wants some help from you?" "To tide over the present, he imagines. But it will be for all time. Now, if you want a handsome estate right in among good old families. You know we heard about it at Thorley. It wouldn't be a bad speculation if one wanted to live there. It's not such a great distance from London." "If one could buy the title," and she sighed. He gave a short laugh and then returned to his list. She leaned back in her luxurious chair and dreamed. They really had something wherewith to purchase the title.
- 85. CHAPTER XVIII TO SEE YOU ONCE AGAIN Mr. and Mrs. Westbury had gone to Wrexford Grange. Laverne was glad to have a few days to herself. At first she wrote a long homesick letter to Miss Holmes. Already she was tired of her new life. Yet more than a year had passed—three years more and she would be free. But how long it looked! After Uncle Jason's tender love she was cruelly hurt by her father's indifference. He was deeply immersed in business and proud of his successes. Indeed, why should he not be? He was shrewd enough to take no honor in coming up from the ranks. He preferred to have his patrons think he had always been quite high on the ladder of fortune. Making money was now his chief enjoyment, his one ambition. Laverne was a pretty enough girl, but not the sort that drew men irresistibly to her side. His wife was much more attractive. And then Laverne brought some remembrances that he wished strenuously to forget, that he had once dismissed from his mind. He had made a little romance of it for his wife's ears, and he had a vague fear that Laverne might recall some disagreeable fact that it would not be so easy to disavow. She never had, but he was not sure how much might linger in her memory. There was always a gulf between the father and the child. He had demanded her mostly to please his wife, the rest to satisfy a little grudge against Jason Chadsey that he had happened to possess
- 86. himself of the episode not at all to his, Westbury's, credit. From the bottom of his heart he wished Chadsey had come back in time to marry Laverne. It had been a most unfortunate step for him, he reasoned. Laverne had been in a way fascinated by Mrs. Westbury's protestations of affection. She had appealed to all that was sweetest and finest in the girl's nature, all these years she had been studying men and women on the emotional side, she was not capable of any intellectual analysis. And though she could assume so much, at heart she had very little faith in her fellow beings, as she measured them mostly by herself. An attractive young girl would draw young people, and she sunned herself in the enthusiasms of youth, they were a tonic to her. She did not mean to grow old, but she had a quality rare in the people who cling to youth, she made no silly assumption further than to use all the arts and aids that she persuaded herself were quite as necessary as a good diet to conserve health. She enjoyed her world, her wealth, her little elusive pretexts and inventions, and was amused to see how easily people who pretended to discrimination were ensnared. At first Laverne had been a new toy, a plaything, a puppet that she could draw in any fashion that she thought best. But presently she was amazed at the child's utter honesty, her shrinking from dissimulation, the surprise at some things she read in the clear eyes. It had been pleasant, but now she was tiring of her toy. Would she be the sort of girl who would draw lovers to her feet and dismiss them with a wave of her fan? There was marriage, of course. This was really her first season. The daughter of a rich man would not lack offers. She wished she was a little less cold, self-contained, indifferent. And now a new scheme had presented itself. Why should not Laverne be Lady Wrexford? If her father became the virtual owner of Wrexford Grange, why would it not be a fine dowry? And they could
- 87. manage that Lord Wrexford should be judicious in expenditures. It might be best that the entail should not be meddled with. Laverne did enjoy the solitude. She was coming to feel that she was watched continually, criticised gently, of course, but often it hurt. And she had not gone down to the real heart of anything. Was there a heart or was it all surface living? She went out to take her drive each day with her maid. Several young friends had called. One afternoon Preston brought up a card. "Mr. Victor Savedra," Laverne read. "He requested especially to see you," Preston said. "I was not sure ——" and she glanced inquiringly. "It is all right, quite right," the girl made answer, but her heart was in her throat, her voice husky. She stood there some seconds, fingering the card. Truth to tell, she felt hurt that Victor had made no effort to see her through all this time, knowing from his own family she was in London. It was hardly her place to appeal to him. Indeed, she had soon learned her old friends were not subjects of pleasure to her new relatives. And now she had quite given up hope with a sad heartache. Laverne walked slowly down the broad staircase, lingered a moment, while she felt her color coming and going in great bounds. Then there was a step, a figure emerged from the reception room, and caught both hands in his. Neither of them spoke, but simply glanced in each other's eyes. He had changed, matured, and was a really handsome young man in the somewhat brilliant Spanish style. But the soft eyes had not lost their olden tenderness. "Oh," he began, "I was afraid I should never see you again," and the glance seemed almost to devour her. "You have been in London all this time." There was the faintest touch of reproach in her tone.
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