Covaraince Matrix Adapted Evolutionary Strategy based design of robust optimal fixed structure controller

In this paper, Covariance Matrix Adapted Evolution Strategy (CMAES) algorithm based design of robust optimal fixed structure controllers for systems with uncertainties and disturbance is addressed. PID controller and second order polynomial structure are considered for fixed structure controller. The design problem is formulated as minimization of maximum value of real part of the poles subject to the robust stability criteria and load disturbance attenuation criteria. The performance of proposed method is demonstrated with two test systems. For the purpose of comparison, already reported results of constrained PSO method are considered. Owing to the randomness of the evolutionary algorithms, 10 trials with independent population initializations are made to acquire a useful conclusion of the performance of the algorithms. It is shown experimentally that the performance of the CMAES-based method is superior to constrained PSO methods in terms of success rate, robust stability, and disturbance attenuation.