Basic Structure of a closed loop control system
In this tutorial I will explain the basic blocks of a closed loop control system.
The system presented in the figure consist a controller, plant (The system we want to control), an output feedback path and the reference or desired input.
Plant : - The plant is the system or process that is to be controlled. Examples : Quadcopter, Aeroplane, Vehcile etc. The system is modeled in the form of a transfer function or state-space equations.
Sensor - The sensor measures the output quantity to provide the output feedback
Controller- It is the brain of the control system. It takes action based on the error signal which is the difference between reference and the measured output quantity.
Different types of controllers:
Proportional + Integral Controller
Proportional + Derivative Controller
Proportional + Derivative + Integral Controller
Reference Input - It is the desired output that we want to achieve. For example in a temperature control system the 20 degree Celsius could be ref. input or in a Quadcopter altitude control system 10 m could be a reference input.