Introduction to Mechatronics Systems- An Overview
- 2. What is Mechatronics? • The word Mechatronics is composed of “mecha” from mechanical and the “tronics” from electronics. Mechanical + Electronics = Mechatronics • The term mechatronics was coined by Tetsuro Mori, a senior Japanese engineer at Yasakawa Company in 1969. • Mechatronics is synergic integration of mechanical engineering, electronics engineering, control engineering and computer science. • A mechatronic system is a computer controlled mechanical system.
- 5. Modules of a Mechatronic System 1. Sensing (a) Sensors (b) Signal Conditioning (c) Analog-to-Digital and Digital-to-Analog Conversion 2. Control (a) Open Loop and Closed Loop Control 3. Action (a) Drive Circuits (b) Actuators (c) Motors
- 7. Components of a Mechatronic System • Mechanical • Electronics • Sensors • Actuators • Control • Computing
- 8. Components of a Mechatronic System • A mechatronic system has at its core a mechanical system which needs to be commanded or controlled by a controller. • The controller needs information about the state of the system. This information is obtained from sensors. • In many cases, the signals produced by the sensors are not in a form ready to be read by the controller and need some signal conditioning operations performed on them. • The conditioned, sensed signals are then converted to a digital form by Analog-to-Digital Convertor (ADC) and are then sent to the controller.
- 9. Components of a Mechatronic System • The controller is the ‘mind' of the mechatronic system, which processes user commands and sensed signals to generate command signals to be sent to the actuators in the system. • Actuators are devices that can convert electrical energy to mechanical energy. • The user commands are obtained from a variety of devices including command buttons, graphical user interfaces (GUIs), touch screens, or pads.
- 10. Basic elements of control system • A control system consists of several elements where each element performs a particular task. • These elements are connected in proper sequence and facilitates signal to flow through them • Different control actions are performed by these elements to obtain a desired output. • Basic elements of control system depends upon the type of control system. • Main types of control system are: A. open loop control system and B. closed loop control system
- 11. Open & Closed Loop System • In some cases, the command signals are sent to the actuators without utilizing any feedback information from the sensors. This is called open-loop system, and for it to work, this requires a good calibration between the input and output of the system. • The more common mode of operation is the closed-loop mode in which the command signals sent to the actuators utilize the feedback information from the sensors. This mode of operation does not require calibration information.
- 13. Open loop control system • Open loop system is a control system in which the output is dependent on the input but the input or controlling action is independent of the output or change in the output. • It is relatively simple, low cost, easy to understand and maintain stability and reliability is relatively good. • Its disadvantages are inaccuracy, slow in response, no optimized control.
- 14. Closed loop system • The disadvantages of open-loop systems, namely sensitivity to disturbances and inability to correct for these disturbances, may be overcome in closed-loop systems. • The closed-loop system compensates for disturbances by measuring the output response, feeding that measurement back through a feedback path, and comparing that response to the input at the summing junction. • Closed-loop systems, then, have the obvious advantage of greater accuracy than open-loop systems. They are less sensitive to noise, disturbances, and changes in the environment.
- 15. Introduction to Mechatronics Every computer controlled system has four basic functional blocks: 1. A process to be controlled 2. Sensors 3. Actuators 4. Controller
- 16. Introduction to Mechatronics The analogy between a human controlled system and computer control system is shown in figure.
- 17. Introduction to Mechatronics If a process is controlled and powered by a human operator, the operator observes the behavior of the system (i.e. using visual observation), then makes a decision regarding what action to take, then using his muscular power takes a particular control action. One could view the outcome of the decision making process as a control or decision signal, and the action of the muscles as the actuator signal which is the amplified version of the control (or decision) signal.
- 18. Introduction to Mechatronics • The same functionalities of a control system can be automated by use of a digital computer as shown in the figure.
- 19. Introduction to Mechatronics • The sensors replace the eyes, the actuators replace the muscles, and the computer replaces the human brain • Every mechatronic system has some sensors to measure the status of the process variables • The sensors are the "eyes" of a computer controlled system • Actuators are the "muscles" of a computer controlled system
- 21. Applications • Smart consumer products: home security, camera, microwave oven, toaster, dish washer, laundry washer-dryer, climate control units, etc. • Medical: implant-devices, assisted surgery, haptic, etc. • Defence: unmanned air, ground, and underwater vehicles, jet engines, etc. • Manufacturing: robotics, machines, processes, etc. • Automotive: climate control, antilock brake, active suspension, cruise control, air bags, engine management, safety, etc.