Vol. 1, 2006
INTRODUCTION TO MECHATRONICS SYSTEMS J.K. Gera Deptt. of Mechanical Engineering
Background The current technological designs are highly complex and interdisciplinary in nature involving synergistic integration of many aspects of engineering knowledge base. The integration of various theories, principles , techniques, methodologies and standards to cater to the pressing needs have long been emerging as new multi-disciplinary subject in the name of mechatronics, which has been attracting not only manufacturers but also engineers, developers, researchers and academicians. Advanced technological designs are highly complex and interdisciplinary nature involving synergistic integration of mechatronics, photonics, computronics and communication. Technological designs have become a high risk endeavor due to the lack of knowledge and experience on interdisciplinary subjects and methods. Synergetic integration is solitarily logic based integration. Combined action and cooperation increases effectiveness and productivity.
Definition Mechatronics is “the synergistic integration of Mechanical Engineering with Electronics and intelligent control algorithms in the design and manufacture of products process”. Synergistic integration means the mechatronic engineers have to study the aspects of engineering that are vital for the design and manufacture of products, process. A graphical representation of Mechatronics is shown Fig. 1
The main technical areas under the research and development domain mechatronics are: • Motion control • Robotics • Automotive systems • Intelligent control
10
Department of Mechanical Engineering
Vol. 1, 2006
• • • • • •
Actuators and sensors Modeling and design System integration Manufacturing Micro devices and optoelectronics Vibrations and noise control
Figure 2 provides an abstract view of the mechatronic discipline. The square like block represents the subject areas the discipline includes and the semicircular projections represent that there exists interaction among the subjects emphasizing multidisciplinary scenario.
Figure 2-Detailed layout of basic Mechatronics
Evolution of Mechatronics Mechatronics has evolved through the following stages: • Primary Level Mechatronics: Integrates electrical signaling with mechanical action at the basic control level for e.g.fluid valves and relay switches • Secondary Level Mechatronics: Integrates microelectronics into electrically controlled devices for e.g. cassette tape player. • Tertiary Level Mechantronics: Incorporates advanced control strategy using microelectronics, microprocessors and other application specific integrated circuits for e.g. microprocessor based electrical motor used for actuation purpose in robots.
Department of Mechanical Engineering
11
Vol. 1, 2006
•
Quaternary Level Mechatronics: This level attempts to improve smartness a step ahead by introducing intelligence ( artificial neutral network and fuzzy logic ) and fault detection and isolation ( F.D.I.) capability into the system.
Scope of Mechatronics The definition of mechatronics is elusive, as is the definition of computer. The scope of Mechatronics is vast and can be enclosed within the following domain of activities: • Marketing: Signifies market research, identification of user needs, information analysis and formulation of product specification. • Manufacturing: Looks into process development, production planning, material handling and quality control. • Design: The concentration is on studying fundamental aspects of sensors, actuators, control and integration methods. Broadly the core of a mechatronics system incorporates Mechanical, Electronics, Control and Information system engineering.
Mechatronic Systems Mechatronic system have become increasingly popular because of their versality, functionality and high integration level. Examples of mechatronic system are : • An aircraft flight control and navigation system, weapon system • Automobile electronic fuel injection, antilock brake systems, collision detection, global positioning system, camless valve operation, active suspension, by wire systems etc. • Automated manufacturing equipment such as robots and numerically controlled (NC) machine tools., autonomous guided vehicles ( A.G.V.). • Smart kitchen and home appliances such as bread machines and clothes washing machines, and even toys. Photocopying machine , automatic cash machine , music system, and video player.
Figure 3 – Scope of Mechatronics
12
Department of Mechanical Engineering
Vol. 1, 2006
Fig. 4 Mechatronic System
Fig. 5 Elements of Mechatronic System The elements of a typical Mechatronics system are shown in Fig. 5
Department of Mechanical Engineering
13
Vol. 1, 2006
• • • • •
The actuators produce motion or cause some action. The sensors detect the state of system parameters, inputs, and outputs devices Digital devices control the system. Conditioning and interfacing circuits provide connections between the control circuits and the input/output devices. Graphical displays provide visual feedback to users.
Mechatronics as Design Philosophy It is “a design philosophy” where mechanical, electrical, electronics components, and it should be considered together in the design stage to obtain an compact, efficient, and economic product design rather than designing the components in stages separately. This is illustrated in fig. 6
Fig. 6 Conventional and Modern Design Approaches
Design trends in mechatronics are oriented to reduction of hardware parts of the systems and increasing the software option volume to improve of the system functionality and system reliability. Typical aspects of the mechatronics area are the applications of new physical principles, (smart) materials, electronic and microelectronic systems, complex computing and controlling technologies and progressive production processes.
14
Department of Mechanical Engineering
Vol. 1, 2006
Future results of these special mechatronics aspects are the smart or intelligent systems suitable for all applications areas of the human life necessity and human interactions to the nature. Smart devices, while the term smart is elusive in precise definition, in the engineering sense we mean the inclusion of elements such as logic, feedback, and computation that in a complex design may appear to simulate human thinking processes. Mechatronic systems are to be built, designed, monitored, controlled and simulated using hardware and software tools(modularity), work bench(platforms) and techniques, considering harware software integration parameters such as modularity, scalability, extendability, flexibility, interoperability, interchangeability etc.
Measurement Systems A fundamental part of many mechatronic system is a measurement system composed of the three basic parts: • • •
The transducer is a sensing device that converts a physical input into an output, usually a voltage. The signal processor performs filtering, amplification, or other signal conditioning on the transducer output. 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.
Fig.7 Examples of Measurement Systems – Digital Thermometer is shown in Fig. 7.
Micro Mechatronics The system integration has another view point by combining micro sensor and actuator technologies, which is defined as “micro-mechatronics”. Micro-mechanics is viewed as giving new birth to another branch of mechatronics showing precision engineering and system integration. This filed introduced
Department of Mechanical Engineering
15
Vol. 1, 2006
the bottoms-up approach from semiconductor technology based on photolithography, and the downsizing/miniaturizing approach from conventional mechatronics, emerging into a new filed as micro-mechatronics. Microsensors are good examples of micro-mechatronics with the development of microprocessors and micro actuators.
Modelling and simulation The behavior of engineering system is studied through modeling and simulation.state of the art simulation, measurement and test technique enable us to accurately predict performance. In a conventional design approach, components of a physical system are designed in isolation and test its feasibility physical prototypes are made. Based on the prototype test results modifications are carried out. Using such approach, several prototypes are required before a satisfactory design is achieved. Since making physical prototypes is time consuming and expensive, a large investment is required, particularly. Alternatively, with the advent computers researchers are able to solve complex equations. Hence, instead of viewing components of a physical system in isolation the whole system equations of motions are derived based on the fundamental principles of the individual components., this is called modelling. Modeling shapes the foundation for understanding, studying and manipulating the behaviour of the systems. The total system equations are then solved using a computer, which is referred to as simulation. The simulation results provide the nature of the system behaviour. Since changing the model parameters and re-running the simulation does not take much time (only in minutes or hours), the number of real prototypes are reduced, and a new product can be brought to the market much quicker than in the conventional approach. This modelling and simulation together is also referred as virtual prototyping, as it serves the purpose of physical prototypes without really making one. The challenges in modelling and simulation or in virtual prototyping are: 1. The methods and ways to write the system equations of motions so that computers take less time to solve; and 2. The numerical methods used to solve the equations so as to obtain realistic results without large numerical errors, which have nothing to do with the physical systems.
Application of modeling and simulation • • • • • •
16
Concept design : a new idea to be examine / discussed / communicated. Design refinement : re-run program with change input data. Design verification : study performance. Test planning : predict behaviour before a real test. System re-construction : study a failure. Teaching and training : useful tool for teaching and training.
Department of Mechanical Engineering
Vol. 1, 2006
Future Trends The future has much to offer. The reduction in component sizes is providing new types of actuator and sensors, which are being increasingly utilized in complex systems such as the provision of low cost radar sensors for autonomous robot systems and automotive uses. Mechatronics allows both to achieve increased functionality for the same dimension of a system, and to reduce its size for the same functionality. As examples, today’s intelligent washing machines incorporate a wide variety of sensors (turbidity, conductivity, temperature, humidity, waster-level, position, torque sensor), in order to optimize the washing cycles and the final washing quality.
Conclusion The knowledge of mechatronics is a prime requirement and is considered as fundamental to engineers of all fields. The concept of mechatronics is very important today to meet the customers’ ever increasing demands and still remain competitive in the global market. Very often a mechanical engineer without the mechatronics background is considered equivalent to a mechanical engineer without the engineering drawing knowledge. The growing importance of mechatronics, a truly multidisciplinary approach to engineering, is becoming increasingly apparent. New products and systems based on the integrated application of mechanics, electronic and computing engineering technologies are demonstrating reduced mechanical complexity, increased performance, and often, previously impossible capabilities. Mechatronics system has become increasingly popular because of their versatility, functionality and high integration level. These advantages have been stimulated by factors including developments in microprocessors, new and improved sensors and actuators, advances in design and analysis methods, simulation tool and novel software techniques. To improve communication, control capabilities, implementation simplicity, efficiency, reliability and safety system design. Mechatronics is the challenge for future intelligent tools. An expansion of today technologies is expected in application of nanoelectgronics, bio and molecular technologies. Future is in micromechatronics to reach the unique quality of the system for new application areas. Mechatronic has a bright future and will grow steadily in the 21st century.
References 1. 2. 3. 4. 5.
David G Alciatore, M B Histand “Introduction to Mechatronics and Measurement System” D Mecrulescu “Mechatronics J W Gardener “Microsensor” N P Mahalik “ Mechatronics Principle Concept & Application” W Bolton “Mechatronics”.
Department of Mechanical Engineering
17
