What is Mechatronics System

Mechatronics is a methodology used for the optimal design of electromechanical products.

A methodology is a collection of practices, procedures, and rules used by those who work in a particular branch of knowledge or discipline. Familiar technological disciplines include thermodynamics, electrical engineering, computer science, and mechanical engineering, to name several. Instead of one, the mechatronic system is multidisciplinary, embodying four fundamental disciplines: electrical, mechanical, computer science, and information technology.

The F-35, a U.S. Department of defense joint strike fighter plane developed by Lockheed Martin Corporation, is an example of mechatronic technology in action. The design metric emphasizes reliability, maintainability, performance, and cost. Multidisciplinary functions, including the on-board prognostics for zero downtime and cockpit technology, are being designed into the aircraft starting at the preliminary design stage.

Multidisciplinary systems are not new. They have been successfully designed and used for many years. One of the most common is the electromechanical system, which often uses a computer algorithm to modify the behavior of a mechanical system. Electronics are used to transduce information between the computer science and mechanical disciplines.

The difference between a mechatronic system and a multidisciplinary system is not the constituents, but rather the order in which they are designed. Historically, multidisciplinary system design employed a sequential design-by-discipline approach. For example, the design of an electromechanical system is often accomplished in three steps, beginning with the mechanical design. When the mechanical design is complete, the power and microelectronics are designed, followed by the control algorithm design and implementation. The major drawback of the design-by-discipline approach is that, by fixing the design at various points in the sequence, new constraints are created and passed on to the next discipline. Many control system engineers
are familiar with the quip:

Design and build the mechanical system, then bring in the painters to paint it and the control system engineers to install the controls.

Control designs often are not efficient because of these additional constraints. For example, cost reduction is a major factor in most systems. Trade offs made during the mechanical and electrical design stages often involve sensors and actuators. Lowering the sensor–actuator count, using less accurate sensors, or using less powerful actuators, are some of the standard methods for achieving cost savings.

The mechatronic design methodology is based on a concurrent (instead of sequential) approach to discipline design, resulting in products with more synergy.

The branch of engineering called systems engineering uses a concurrent approach for preliminary design. In a way, mechatronics is an extension of the system engineering approach, but it is supplemented with information systems to guide the design and is applied at all stages of design—not just the preliminary design step—making it more comprehensive. There is a synergy in the integration of mechanical, electrical, and computer systems with information systems for the design and manufacture of products and processes. The synergy is generated by the right combination of parameters; the final product can be better than just the sum of its parts. Mechatronic products exhibit performance characteristics that were previously difficult to achieve without the synergistic combination. The key elements of the mechatronics approach are presented in Figure 1-1.

Even though the literature often adopts this concise representation, a clearer but more complex representation is shown in Figure 1-2. Mechatronics is the result of applying information systems to physical systems. The physical system (the rightmost dotted block of Figure 1-2) consists of mechanical, electrical, and computer systems as well as actuators, sensors, and real-time interfacing. In some of the literature, this block is called an electromechanical system.

FIGURE 1-1 MECHATRONICS CONSTITUENTS

FIGURE 1-2 MECHATRONICS KEY ELEMENTS

A mechatronic system is not an electromechanical system but is more than a control system.

Mechatronics is really nothing but good design practice. The basic idea is to apply new controls to extract new levels of performance from a mechanical device. Sensors and actuators are used to transduce energy from high power (usually the mechanical side) to low power (the electrical and computer side). The block labeled “Mechanical systems” frequently consists of more than just mechanical components and may include fluid, pneumatic, thermal, acoustic, chemical, and other disciplines as well. New developments in sensing technologies have emerged in response to the ever-increasing demand for solutions of specific monitoring applications. Microsensors are developed to sense the presence of physical, chemical, or biological quantities (such as temperature, pressure, sound, nuclear radiations, and chemical compositions). They are implemented in solid-state form so that several sensors can be integrated and their functions combined.

Control is a general term and can occur in living beings as well as machines. The term “Automatic control” describes the situation in which a machine is controlled by another machine. Irrespective of the application (such as industrial control, manufacturing, testing, or military), new developments in sensing technology are constantly emerging.

Mechatronics Systems