Fuzzy Intervention in Pid Controller Design

This paper presents a recent development of PID controllers. The proposed controller design aims to overcome the drawbacks of classical PID controller, such as: integrator windup due to the saturation in the actuator and the slow response to reject disturbances. Classical approaches to treat the windup problem in PID controller design are discussed and analyzed such as conditional integration method, limited integrator method, tracking anti-windup and modified tracking anti-windup. The proposed controller consists of basic PID blocks: Proportional, Derivative, and Integral actions plus a fuzzy anticipation block to modify the control signal according to operating conditions. The fuzzy anticipation block provides feed-forward correction terms to speed-up the system response and to retain the desired output. This block receives all different signals in PID block and generates anti-windup action to improve the system behavior. This action also compensates rapidly the disturbance effect on the system response. The proposed control design methodology is tested on a numerical example via simulation. The simulation work is carried out using MATLAB/SIMULINK environment. This environment is very easy to elaborate fuzzy toolbox in simulation. The obtained results affirm the potential of the proposed control methodology to add self-autonomy to the system behavior.