Mechtronics involves, what termed, systems. A system can be thought of as a box which has an input and an output where we are not concerned with what goes on inside the box but only the relationship between the output and the input. Thus, for example, a motor may be thought of as a system which has its input electric power and as output the rotation of shaft.
A measurement system can be thought of as a black box which is used for making measurements. It has as its input the quantity or object being measured and its output the value of that quantity or object. Also can in general be considered to be made up of three elements as following:
- A sensor which responds to the quantity or object being measured by giving as its output a signal which is related to the quantity.
- A signal conditioner takes the signal from the sensor and manipulates it into a condition which is suitable for either display or in the case of a control system.
- A display system where the output from the signal conditioner is displayed this might be for example be a pointer moving across a scale or a digital readout.
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A control systems is maintaining constancy of process and operations according to required conditions and provides the appropriate response in order to obtain the required action. There are two basic forms of control systems as following:
- Open-loop control system the output from the system has no effect on the input signal, there is no information feedback to the element to adjust and maintain the required response and action. Also open-loop systems have the advantage of being relatively simple and consequently low cost with generally good reliability. However, they are often inaccurate since there is no correction for error.
- Closed-loop control system the output does have an effect on the input signal, modifying it to maintain an output signal at the required value. Also closed-loop systems have the advantage of being relatively accurate in matching the actual to the required values
