Page 207 - Mechatronic Components Roadmap to Design

Chapter 14

Controls Theory and

Applications

ABSTRACT
Any mechanical system consists of three basic parts: mechanical, electronics, and soft-
ware. All of these three systems have tolerances. Mechanical parts have both dimensional
and shape tolerances, because it would be too costly to manufacture mechanical parts
without any tolerances. The tolerances show the acceptable error in the part. Because
of the tolerances in dimension, the mechanical model of the system cannot be exact; if
the part is bigger, it will be heavier in the tolerance limits. Electrical parts also have tol-
erances; for example, a resistor cannot have an exact value—it is also manufactured with
tolerances. This means the signal going over this resistance will also have a variation. In
software, there are also tolerances. For example, one a number is defined as floating or
long so it is represented slightly different. There is also truncation error in the software.
When all these three kinds of tolerances and errors add up with the noise in the system, it is
not possible for the system to act as in theory. This is why mechatronic systems need con-
trol. The control of the system is achieved with software mostly inside a microcontroller.
The system receives feedback signals from the sensors and with the predefined calcula-
tions responds with the actuators and tries to achieve the desired purpose.

Mechatronic Components. https://doi.org/10.1016/B978-0-12-814126-7.00014-1
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