A Novel Fractional Order Fuzzy PID Controller and Its Optimal Time Domain Tuning Based on Integral Performance Indices

TL;DR

This paper introduces a new fractional order fuzzy PID controller optimized via genetic algorithms, demonstrating superior control performance on nonlinear and unstable processes compared to traditional controllers.

Contribution

It proposes a novel fractional order fuzzy PID controller with optimized fractional differ-integrations and scaling factors, improving control performance over existing methods.

Findings

Outperforms conventional PID and fuzzy PID controllers in simulations

Effective in controlling delayed nonlinear and unstable processes

Optimized using genetic algorithms for minimal integral error indices

Abstract

A novel fractional order (FO) fuzzy Proportional-Integral-Derivative (PID) controller has been proposed in this paper which works on the closed loop error and its fractional derivative as the input and has a fractional integrator in its output. The fractional order differ-integrations in the proposed fuzzy logic controller (FLC) are kept as design variables along with the input-output scaling factors (SF) and are optimized with Genetic Algorithm (GA) while minimizing several integral error indices along with the control signal as the objective function. Simulations studies are carried out to control a delayed nonlinear process and an open loop unstable process with time delay. The closed loop performances and controller efforts in each case are compared with conventional PID, fuzzy PID and PI{\lambda}D{\mu} controller subjected to different integral performance indices. Simulation results show that the proposed fractional order fuzzy PID controller outperforms the others in most cases.