An improved fuzzy PID controller with fuzzy rule based set-point weighting technique

Abstract

An improved fuzzy PID controller is designed with fuzzy rule-based set-point weighting mechanism. The proposed fuzzy PID controller is designed by adding control actions of fuzzy PI and fuzzy PD controllers with proper scaling factors. The set-point weighting factor is obtained online through a simple fuzzy inference system based on process change of error. The proposed fuzzy set-point weighting scheme offers a considerable amount of performance improvement for second order linear and nonlinear processes compared to other well-known set-point weighting techniques. This fact has been verified through simulation study and real time implementation on a DC servo position control system. Performance analysis reveals that the proposed scheme is able to provide performance enhancement during both set-point tracking and load rejection phases along with substantial robustness during close-loop operation.