Optimal design of PI/PD controller for non-minimum phase system

Abstract

It is still an open problem to eliminate the undershoot caused by zeros in the right-half plane of non-minimum phase systems (NMPS). In this paper, a two-stage PI/PD controller is investigated on the basis of particle swarm optimization (PSO) to decrease peak overshoot, maximum undershoot, settling time and rise time of non-minimum phase (NMP) system simultaneously. PSO is a global stochastic evolutionary algorithm. It tries to find optimal regions of complex searching space through the interaction of particles in the population. The predominance of the algorithm is its excellent performance and simple implementation. Numerical simulation results illustrate the efficiency of the proposed controller compared with a genetic algorithm -simulated annealing (GA-SA) PID controller in point of improvement of performances of a step response, like fast settling time, small undershoot and small overshoot.