1. CHAPTER -1 INTRO D UCTION Contents  1.1 Definition of Mechatronics 1.1.1 History 1.1.2 Disciplines  1.2 Key Elements  1.3 Systems  1.4 Applications

2. 1.1 Definition The term "mechatronics" was first assigned by Mr. Tetsuro Mori, a senior engineer of the Japanese company Yaskawa, in 1969. He defined mechatronics in this way: The word, mechatronics, is composed of “mecha” from mechanism and the “tronics” from electronics. In other words, technologies and developed products will be incorporating electronics more and more into mechanisms, intimately and organically, and making it impossible to tell where one ends and the other begins.

3. Definition… Thedefinitionofmechatronicscontinuedtoevolveafter Mr. Tetsuro Mori suggested the original definition. One of quoted definition of mechatronics was presented by Harashima, Tomizuka, and Fukada in 1996. In their words: Mechatronics is defined as the synergistic integration of mechanical engineering, with electronics and intelligent computer control in the design and manufacturing of industrial products and processes.

4. Definition… That same year, another definition was suggested by Auslander and Kempf: Mechatronics is the application of complex decision making to the operation of physical systems. Paruschev´s definition (1996): Mechatronics may be taken as a complex of ideas, methods and means to create computer-controlled and programmable mechanic systems with settable functionality, linked to energetic and power interactions of mechanic subsystems with their ambient.

5. Definition… Yet another definition due to Shetty and Kolk appeared in 1997 : Mechatronics is a methodology used forthe optimal design of electromechanical products. More recently, we find the suggestion by W. Bolton : A mechatronic system is not just a marriage of electrical and mechanical systems and is more just a control system; it is a complete integration of all of them.

6. 1.1.1 HISTORICAL DEVELOPMENT OF MECHATRONIC SYSTEMS

7. The genesis of mechatronics is the interdisciplinary area relating to mechanical engineering, electrical and electronic engineering, and computer science. 1.1.2 Disciplines

8. 1.2.1 information systems  Information systems include all aspects of information transmission from signal processing to control systems to analysis techniques.  An information system is a combination of four disciplines: communication systems, signal processing, control systems, and numerical methods.  In mechatronics applications, we are most concerned with modeling, simulation, automatic control, and numerical methods for optimization. 1.2.2 Mechanical Systems  Mechanical systems are concerned with the behavior of matter under the action of forces. Such systems are categorized as rigid, deformable, or fluid in nature.  Newtonian mechanics provides the basis for most mechanical systems and consists of three independent and absolute concepts: space, time, and mass. A fourth concept, force, is also present but is not independent of the other three. 1.2 Mechatronoics key elements

9. 1.2.3 Electrical Systems  Electrical systems are concerned with the behavior of three fundamental quantities: charge, current, and voltage (or potential).  When a current exists, electrical energy usually is being transmitted from one point to another.  Electrical applications in mechatronic systems require an understanding of direct current (DC) and alternating current (AC) circuit analysis, including impedance, power, and electromagnetic as well as semiconductor devices (such as diodes and transistors).

10. 1.2.4 Sensors and Actuators  Sensors are required to monitor the performance of machines and processes. Using a collection of sensors, one can monitor one or more variables in a process.  Sensing systems also can be used to evaluate operations, machine health, inspect the work in progress, and identify part and tools.  Some of the more common measurement variables in mechatronic systems are temperature, speed, position, force, torque, and acceleration.  When measuring these variables, several characteristics become important: the dynamics of the sensor, stability, resolution, precision, robustness, size, and signal processing.

11. 1.2.5 Real-Time Interfacing  The real-time interface process really falls into the electrical and information system categories but is treated independently as was computer system hardware because of its specialized functions.  In mechatronics, the main purpose of the real-time interface system is to provide data acquisition and control functions for the computer. The purpose of the acquisition function is to reconstruct a sensor waveform as a digital sequence and make it available to the computer software for processing. The control function produces an analog approximation as a series of small steps.  For mechatronic applications, real-time interfacing includes analog to digital (A/D) and digital to analog (D/A) conversion, analog signal conditioning circuits, and sampling theory.

12. Mechatronoics key elements cont…  The study of mechatronic systems can be divided into the following areas of specialty: 1.Physical Systems Modeling 2.Sensors and Actuators 3.Signals and Systems 4.Computers and Logic Systems 5.Software and Data Acquisition  As the field of mechatronics continues to mature, the list of relevant topics associated with the area will most certainly expand and evolve

13. 1.3 Systems  System can be thought of as a unit which has an input and output devices and is prepared to perform some defined function.  It is not important here to discuss the function of the process but only concerned with the input and the output.  In designing mechatronic systems, one of the steps involved is the creation of a model of the system so that predictions can be made regarding its behaviour when inputs occur. Example: A motor can be thought of as system with electric input and rotation of the shaft as the output. A system can be a measurement system or a control system

14. 1.3.1 Measurement System  It can be thought of as a box carrying out the action of measurement.  It has an input quantity to bemeasured and the output as the value of that quantity.

15. Elements of measurement system A fundamental part of many mechatronic systems is a measurement system composed of the three basic parts illustrated in Figure below. I.The transducer is a sensing device that converts a physical input into an output, usually a voltage. II.The signal processor performs filtering, amplification, or other signal conditioning on the transducer output. The term sensor is often used to refer to the transducer or to the combination of transducer and signal processor. III.Finally, the recorder is an instrument, a computer, a hard-copy device, or simply a display that maintains the sensor data for online monitoring or subsequent processing

16. 1.3.2 Control Systems  Control means regulate, manipulate or adjust.  Body temperature control is the natural control system.  It can be thought of as a box which is used to control the output to a particular value or a sequence of values.

17. 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

18. 1.3.3 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.

19. cont.  Open-loop control systems are often used with processes that require the sequencing of events with the aid of “ON-OFF” signals. For example: a washing machines which requires the water to be switched “ON” and then when full is switched “OFF” followed by the heater element being switched “ON” to heat the water and then at a suitable temperature is switched “OFF”, an

20.  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. 1.3.4 Closed loop system

21. Basic elements of a closed-loop system A basic closed-loop system consists of five elements. 1.Comparison element This compares the required or reference value of the variable condition being controlled with the measured value of what is being achieved and produces an error signal. Error Signal = Reference Value Signal - Measured Value Signal 2. Control element This decides what action to take when it receives an error signal. 3. Correction element The correction element produces a change in the process to correct or change the controlled condition. 4 Process element The process is what is being controlled. 5 Measurement element The measurement element produces a signal related to the variable condition of the process that is being controlled. cont.

22. Example: a simple control system used to maintain a constant water level in a tank.

23. 1.4 Applications  Home  Air Plane  Military  Robotics

24. 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. Defense: unmanned air, ground, and underwater vehicles, jet engines, etc. Applications…

25. Application… Manufacturing: robotics, machines, processes, etc. Automotive: climate control, antilock brake, active suspension, cruise control, air bags, engine management, safety, etc. Network-centric, distributed systems: distributed robotics, tele-robotics, intelligent highways, etc.

26. Home Automation Using a computer: –Turn on the lights at preset times –Adjust brightness –Turn on the heat at preset times or temperatures –Serve as a security system

28. Robotics

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