Parameter optimization of PID controller based on complex system genetic algorithm in electro-hydraulic servo control system

In this paper, a novel method for finding a set of appropriative proportional-integral-derivative (PID) controller parameters in an electro-hydraulic servo control system is presented. In this method, a new genetic algorithm called complex system genetic algorithm (CSGA) is designed, which integrates complex system theory into genetic algorithm and redesigns genetic algorithm´s (GA) elements such as selecting operator, crossover operator and mutation operator. And correspondingly, a performance criterion including the information of overshoot, rise time, settling time and steady-state error is also proposed as our fitness function. Then the application of CSGA to get optimal PID parameters is described in detail. At last, by the actual compare experiments of using our proposed method and traditional way in an electro-hydraulic servo control system respectively, it demonstrates that our method can find optimal PID parameters effectively and rapidly.