Robust PID controller design using genetic algorithm for wastewater treatment process

A novel approach for H∞ robust PID synthesis is developed for wastewater treatment system. In operational terms, the simplification model is obtained by simplifying the Activated Sludge Model No.1 (ASM1). The main objective of this paper is to synthesize a robust PID control structure, which keep the substrate concentration and dissolved oxygen concentration below standards by law with the various disturbances. Different from the traditional design method, the robust PID controller is designed based on the H∞ specifications in combination with a genetic algorithm (GA). The genetic algorithm is used to tune the optimized PID controller parameters constrained by H∞ specifications. The simulation results show that the closed-loop wastewater treatment control system satisfies given multiple H∞ specifications and has fast tracking ability and good ability to overcome the noise disturbance. The proposed idea also can be used to deal with many complex output feedback control problems.