Fuzzy I+PD controller for stiction compensation in pneumatic control valve

摘要

Stiction in control valves induces oscillations in process variables which consequently bring down product quality and efficiency, quickens wear and tear, and prompts unsteadiness in the plant. In this paper, an intelligent controller is utilized to suppress the effect of stiction in a pneumatic control valve by mitigates the stiction based oscillations in process variables and controller output. It is developed by cascading a fuzzy integral controller with a conventional proportional plus derivative controller i.e. fuzzy I+PD controller. The controller is designed with Matlab/Simulink environment. A comparative study is performed between fuzzy I+PD and conventional PID controllers for their setpoint following and disturbance rejection at different operating points on a laboratory scale pressure process. The experimental results reveal that the performance of fuzzy I+PD controller is much better, it efficiently compensates the stiction based oscillations, and improves the closed loop performance as compared to PID controller.