Constant Phase Based Design of Robust Fractional PI Controller for Uncertain First Order Plus Dead Time Systems

Abstract

AbstractA new design method of a robust fractional order PI controller for uncertain First Order Plus Dead Time systems is proposed in this paper. The proposed design method uses a numerical optimization algorithm to determine the unknown controller parameters. The main objective of the proposed design method is improving the robustness in degree of stability to gain variations and the stability robustness to the other parameters variations that affect the phase by imposing a constant phase margin to the corrected open loop system in a pre-specified frequency band. Several simulation examples are presented to design the robust fractional PI controller and test the robustness for different forms of uncertainty.KeywordsNumerical optimizationFractional PI controllerStability robustnessUncertaintyTime delay system