An Unified Modeling on Electro Hydraulic Position Servo System and Nonlinear Control

On the basis of electro-hydraulic position servo system(EHPSS) with asymmetry cylinder and asymmetry valve, an unified nonlinear system model was provided to represent the actual system. Then a nonlinear PI predictive control (NPIPC) approach with nonlinear disturbance observing was put forward and was applied to a guide alignment EHPSS of high-speed elevator. Simulation and actual control results show that the proposed controller has better response performance than conventional PID controller; simultaneously, can effectively address the tracking control application of electro-hydraulic servo system.