Dynamic Set-Point Weighted Fuzzy PID Controller

A fuzzy PID controller with dynamic set-point weighting technique is proposed. Fuzzy PID controller is realized by combining the control actions produced by a fuzzy PI and fuzzy PD controllers with suitable output scaling factors. Input to the fuzzy controllers i.e., error and change of error are calculated from the dynamically weighted set-point for each sampling instant. The dynamic weighting factor is calculated online from a simple relation consisting of normalized change of error and normalized process dead time. The proposed dynamic set-point weighted fuzzy PID controller provides a significant amount of performance enhancement for higher order processes with dead time, verified through simulation as well as real time implementation. Unlike to the conventional fixed set-point weighting which offers only improved set-point response, our proposed dynamic set-point weighting is capable to provide simultaneous improvement during both the set-point tracking as well as load variation with considerable robustness in close-loop behavior.