ABSTRACT
A proportional integral derivative (PID) controller is a control loop feedback
mechanism widely used in industrial control systems. Fig. 1.1 is a block diagram of
the classical PID controller. A PID controller continuously calculates an error value
e(t) as the difference between a desired setpoint r(t) and a measured process variable y(t) and applies a correction based on proportional, integral, and derivative terms (denoted P, I, and D, respectively) which give their name to the controller.
