Introduction:
Design, development, modification, and control of a mechatronic system require an understanding and a suitable “representation” of the system; specifically, a “model” of the system is required.
Any model is an idealization of the actual system. Properties established and results derived are associated with the model rather than the actual system, whereas the excitations are applied to and the output responses are measured from the actual system.
Dynamic Models and Analogies
A mechatronic system may consist of several different types of components, and it is termed a mixed system. It is useful then to use analogous procedures for modeling such components. In this manner the component models can be conveniently integrated to obtain the overall model.
In particular, analytical models may be developed for mechanical, electrical, fluid, and thermal systems in a rather analogous manner, because some clear analogies are present among these four types of systems. In view of the analogy, then, a unified approach may be adopted in the analysis, design, and control of mechatronic systems.
Terminology
Each interacted component or element of a mechatronic system will possess an input/output (or cause-effect, or causal) relationship.
A dynamic system is one whose response variables are functions of time, with no negligible “rates” of changes. Also, its present output depends not only on the present input, but also on some historical information (e.g., previous input or output). A more formal mathematical definition can be given, but it is adequate to state here that a typical mechatronic system, which needs to be controlled, is a dynamic system.
A model is some form of representation of a practical system. An analytical model (or mathematical model) comprises equations (e.g., differential equations) or an equivalent set of information, which represents the system to some degree of accuracy.
Sometimes, a set of curves, digital data (table) stored in a computer, and other numerical data—rather than a set of equations—might be termed an analytical model if such data can represent the system of interest.
