The basic concept
Control system means through which can the way according to want to maintain and change the machine, or other devices within the amount of any interest or variable. Control system is at the same time in order to make the ideal state of the controlled object to the expected implementation. Control system to be controlled object need a steady state.
For example, suppose you have a car driving system, the speed of the car is a function of its accelerator position. By controlling the pressure of the accelerator pedal speed can keep want (or can reach speeds to change). The motor drive system (accelerator, carburetor and engine vehicle) to form a control system.