Parameters optimization based on evolutionary algorithm for nonlinear hydraulic servo system

Directing to the nonlinear factors existed in hydraulic servo system, this paper focuses on fuzzy PID controller whose scaling factors and membership functions are optimized by evolutionary algorithm simultaneously to achieve high performance. With the improved genetic algorithm of sub population and dynamic time variant mutation, evolutionary algorithm can search the optimal state effectively. The scaling factors map the variable into universe of discourse while the tuning of scaling factors and fuzzy membership functions. Application of hydraulic servo system illustrates the effectiveness of the proposed technique.