Self-Adapting Fuzzy-PID Control of Variable Universe in the Non-linear System

To solve the non-linear system control problem in the hydraulic servo control system, the self-adapting fuzzy-PID control of variable universe is introduced. By analyzing the phase plane characteristics of step response, the fuzzy control rule base which decreased cases of relying on experts´ experience was established. According to error variety, the discourse universe of the input and output fuzzy sets was adjusted to get the precise PID parameters on line. The simulation results show that this method is superior to general fuzzy-PID control. It can efficiently reduce the steady-state error and has stronger interference immunity. The experiment result of the hydraulic servo test-bed farther validates the better control performance of the proposed method.