Non-fragile robust PI controller design using co-variance matrix adaptation evolutionary strategy

Abstract

This paper discusses the application of Co-variance Matrix Evolutionary Strategy (CMA-ES) in the design of non-fragile robust PI controller. The desired maximum sensitivity of the closed loop system is considered as an objective and success rate of stability under probabilistic controller uncertainty is taken as a constraint for non-fragile robust PI controller design problem. Success rate of stability is calculated using Monte Carlo simulation (MCS) under probabilistic controller perturbation. CMA-ES finds the optimal controller parameter based on robustness objective and nonfragileness constraint. The Single Input Single Output (SISO) first order sugar cane raw juice neutralization process and second order Irrigation canal systems are considered as a test systems. The performance of the CMA-ES designed non-fragile robust PI controller is compared with the flat phase concept based PI controller and Astrom suggested PI controller for both test systems. Simulation results demonstrated that CMA-ES based non-fragile robust PI controller has better performance in robustness as well as non-fragileness. © 2013 Springer International Publishing.