Robo unit4- Robot Programming.pptx
- 1. Robot Programming Mr.A.P.ARUN PRAVIN Assistant Professor Department of Mechanical Engineering St.Peter’s College of Engineering and Technology
- 2. Introduction A robot program can be defined as a path in space to be followed by the manipulator, combined with peripheral actions that support the work cycle. Examples of the peripheral actions include opening and closing the gripper, motion control, speed control, performing logical decision making, and communicating with other pieces of equipment in the robot cell. Robot Operating System Three basic modes of operations of the robot language operating system (a) Supervisory mode: Define locations in space using teach pendant, set the speed control, store the relevant program, (b)Compile and edit mode: Provide an instruction set that allows user to compile, edit existing program. User can modify or insert changes in the existing program. (c) Execute mode: Runs the program. The robot performs the sequence of instructions in the program
- 3. In a robot, there are 3 basic modes of operation: Monitor mode Edit mode Run or Execute mode Monitor mode: Programmer define locations, load a particular information in a register, save transfer programs from storage. Move back and forth into edit or run mode Edit mode: Programmer can edit or change set of instructions. Run or Execute mode: Pre defined task can be executed in run mode. Dry run can be tested. Debugging. Robot Basic Modes of Operation
- 4. 1. Manual Programming Method 2. Walk through Programming Method 3. Lead through Method (or) Teach Pendant 4. Off-line Programming Method Methods of Robot Programming Manual Method This method is not really programming in the conventional sense of the word. It is more like setting up a machine rather than programming It is the procedure used for the simpler robots and involves setting mechanical stops, cams, switches, or relays in the robot's control unit. For these low-technology robots used for short work cycles (e.g. pick- and-place operations).
- 5. Walkthrough Method In this method the programmer manually moves the robot's arm and hand through the motion sequence of the work cycle. Each movement is recorded into memory for subsequent playback 'during Production. The speed with which the movements are performed can usually be controlled independently, so that the programmer does not have to worry about the cycle time during the walkthrough. The main concern is getting the position sequence correct. The walkthrough method would be appropriate for spray painting Welding robots. Work cycle is taught to robot by moving the manipulator through the motion cycle and simultaneously entering the program into controller
- 6. Lead through methods The traveling of robots is based on the desired movements, and it is stored in the external controller memory. There are two modes of a control system A Run Mode (The program executed in the run mode) and Teach Mode (The program is taught in the teach mode). The leadthrough programming method can be done by two methods namely: Limitation: Lead through programming is not readily compatible with modern computer based technology. Powered Lead through Method: A teach pendant is incorporated in this method for controlling the motors available in the joints. It is also used to operate the robot wrist and arm through a sequence of points. The playback of an operation is done by recording these points. Some of the key applications are spot welding, machine loading & unloading, and part transfer process. Manual Lead through Method: In this method, the robot‘s end effectors is moved physically by the programmer at the desired movements. Sometimes, it may be difficult to move large robot arm manually. To get rid of it a teach button is implemented in the wrist for special programming. The manual leadthrough method is also known as Walk Through method.
- 7. Teach pendant The major areas of the Teach Pendant are Data Entry Buttons Input data, YES/NO, DEL, Numeric buttons, Return or Enter key decimal point , REC/DONE button, Emergency Stop Switch User LED & Manual State LEDs Mode Control Buttons Enable arm power when necessary. Manual Control Buttons Speed Bars Control the robot‘s speed and direction. Slow Button The slow button selects between the two different speed ranges of the speed bars. Predefined Function Buttons The predefined function buttons display of coordinates, clear error, etc Programmable Function Buttons Soft Buttons
- 8. Classificationof Robot Languages Robot languages can be grouped broadly into three major classes: First generation language Second generation language World modelling and task-oriented object level language / High Level Computer language First generation language The first generation language provides an off-line programming in combination with the programming through robot pendant teaching. The capability of a first generation language is limited . Motion level languages Second generation language Motion control. Advanced sensor capabilities Limited intelligence Communications and data processing. High Level Computer language High level computer languages are used AL, VAL, RAIL, RPL, WAVE, HELP, JARS
- 9. PresentRobot Offline Programming Languages MH1 (Mechanical Hand One) The first robot language capable of describing operations with programmable commands, developed at MIT by H. A. Ernst in1960-1961. The available language commands are: MOVE - indicating a direction and speed UNTIL -operate until a specific sensor condition occurs IF GOTO - branch to a new location in the program on a specific condition IF CONT - branch to continue action on a specific condition
- 10. WAVE WAVE, developed at Stanford University, was the first general purpose robot programming system. The most important features were: 1. Specification of compliance capability in Cartesian coordinates. 2. Coordination of joint motions to provide for continuity of velocities and accelerations through trajectory turning points or via points. 3. Description of end effector positions in Cartesian coordinates. 4. Guarded move capability, so that sensory information could be used to terminate a move when the end effector touched something
- 11. AL is a high-level programming system for specification of manipulator tasks such as automatic assembly in production line manufacturing. AL has a considerable effect on other languages and has emerged as one of the leading contenders for a common robotic language. It was developed at Stanford University in 1974 and has been improved It has an ALGOL-like source language, a translator to convert programs into run able code, and a runtime system for controlling manipulators and other devices. Trajectory calculations are done at compile time and are modified during runtime as necessary. Two or more objects can be handled as one by the use of AFFIX commands that cause them to appear as one object. Force sensing and compliance are implemented by a number of subroutines and by condition monitor statements in the syntax of the language. There are signal statements and wait statements available when one process must wait for the completion of another process. These and other statements make possible the coordinated operation of two or more robot arms. Arm and hand movement commands are available to control moves, velocities, forces, and torques. AL (Assembly Language)
- 12. AML (A Manufacturing Language) AML was developed in 1976 at IBM’s T.J. Watson Research Labs for assembly related tasks. AML provides a systems environment in which different user robot programming interfaces may be built. It supports joint space trajectory planning, subject to position and velocity constraints. Relative and absolute motion can be handled, and sensor monitoring can interrupt motions as necessary. The most unique capability of AML is its operations on data aggregates, so that many operations on vectors, rotations, and coordinate frames can be handled as multiple operations in one command. This capability makes the language more difficult to understand but simplifies programming and control. The advantage of using AML is that integers, real numbers and strings can be specified in the same aggregate which is said to be an ordered set of constants or variables. An aggregate can be used to specify coordinate values of the robot’s joints or wrist position and orientation.
- 13. MCL US Air force ICAM project led to the development of another manufacturing control language known as MCL by McDonnel—Douglas. This is a modification of the popular APT (Automatically Programmed Tooling) language used in CNC machine tools as many similar commands are used to control machine tools in CAM applications. Lines, circles, planes, cylinders and many other complex geometrical features can be defined in MCL. RAIL RAIL was developed by Automatic for robotic assembly, inspection, arc welding and machine vision. A variety of data types as used in PASCAL can be used. An interpreter is used to convert the language into machine language commands. It uses Motorola 68000 type microcomputer system; It supports many commands and control of the vision system
- 14. VAL ( Versatile Algorithmic Language) Developed by augmentation of an existing language (BASIC) is VAL, developed by Victor Scheinman for the Unimation Corporation in the year 1975. VAL uses simple words to describe operations to be performed by the robot which leads to real time programming as given below: 1. Specify and transform the coordinates of positioning points both in a Cartesian system and joint angles. 2. Edit robot programs written in VAL. 3. Manage the execution of user programs. VAL provides for speed control, grasping, arm movement, and signaling in a simple, easy-to-understand framework. The need for a signal to other robots and machines is handled effectively by the use of the interlock commands such as WAIT, SIGNAL and DELAY, which take action on the occurrence of specific events. VAL is a low level language and calls there fore for detailed planning of all actions. VAL provides the executing commands suitable for PUMA robot for the applications in assembly, arc welding, spray painting and material handling. In VAL, both teaching (Interlock commands) and offline programming can be used in an effective way. This language is modified into VAL II by adding some more instructions for the operator convenience.
- 15. Motion Control: MOVE command. MOVES command. DMOVE command. APPRO command. DEPART command. APPROS or DEPARTS commands. CIRCLE command. VAL SYSTEM AND LANGUAGE
- 16. Hand Control: ( End Effector Command) OPEN and CLOSE commands. OPENI and CLOSEI commands. CLOSEI 75 in VAL II, if a servo-controlled gripper is used, then this command causes the gripper to close immediately to 75 mm. A gripper closing command is also given by GRASP 20, 15 MOVET PART, 30 Causes the gripper to move to position, PART with an opening of 30 mm by Joint Interpolated Motion. Sensor Commands SIGNAL M ON SIGNAL M OFF WAIT N DELAY X SEC
- 17. Location, Assignment and Modification: The instructions that do the same as the corresponding monitor commands SET and HERE commands. Program Control: SETI command sets the value of an integer variable to the result of an expression TYPEI displays the name and value of an integer variable. GOTO20 GOSUB and RETURN PAUSE START and END
- 19. Step Move or signal Comments 0 Move 1, 1 Start at home position 1 Move 8, 1 Move to wait position 2 WAIT 1, 1 Wait for press to open 3 Move 8, 8 Move to pickup point 4 SIGNAL 5 Signal gripper to close 5 DELAY 1 SEC Wait for gripper to close 6 Move 8, I Move to safe position 7 SIGNAL 4 Signal press that hand is clear 8 Move 1, 1 Move around press column 9 Move 1, 8 Move to tote pan 10 SIGNAL 6 Signal hand to open 11 DELAY 1 Wait for gripper to open
- 21. 1 WSETI Triangle Weave 2 WSET2 Weld 3 WSET3 Trapezoidal Weave 4 WVSET1 Weave 5 WVSET2 Weld 6 MOVE X1 7 MOVE X2 8 WSTART 1 ,1 9 MOVES X3 10 WEND 0.5 11 WSTART 2,2 12 MOVES X4 13 CIRCLE X4, X5, X6 14 MOVES X7 15 CIRCLE X7, X8, X9 16 MOVES X10 17 WEND 0.5 18 WSTART 3, 1 19 MOVES X11 20 CREATE FILL 0.8, 3 21 WEND 0.5 22 MOVE X12 23 END