ITAE-optimal PI controller based on Genetic Algorithm for low-order process with large time delays

Abstract

For low order process with large time delay, a kind of optimal PI controller tuning method is proposed based on generalized Hermite-Biehler theorem and Genetic Algorithm. Firstly, the calculation method of parameter stable region of PI controller that can stabilize a low order process with time delay is proposed by using the generalized Hermite-Biehler theorem. Then the optimum PI controller parameters are obtained within this region based on ITAE criterion and genetic algorithm. A PI controller tuning formula is finally obtained by nonlinear fitting of optimization results, which has the capability to cover the low order process with normalized time delays up to 100. Monte-Carlo stochastic experiment on robust performance indicates that the proposed PI controller tuning method has good performance robustness when parameter uncertainty occurs compared with other four PI tuning methods.