A system is a combination of devices and components connected together by some form of regular interactions to act together and perform a certain objective. The system may be physical, biological, economic and the like.
The term control means to regulate, to direct or to command. Thus, a control system may be defined as a combination of devices and components connected or related so as to command, direct or regulate itself or another system.
Control systems are used in many applications, for example, the control of temperature, liquid level, position, velocity, flow, pressure, acceleration, etc.
Let us consider the driving system of an automobile. Speed of the automobile is a function of the position of its accelerator. ...