Modelling the electro-hydraulic position servo system based on disturbance observer

Proportional valve-controlled electro-hydraulic position servo system has advantages of low cost and high dependability, but the friction of proportional valve restricts its application in industrial control system. In this paper, the model of proportional valve-controlled electro-hydraulic positon servo system has been established. Aiming at the friction in position servo system, the theoretical analysis on the basis of Stribeck model has carried on. In order to eliminate the effect of friction, the control method based on disturbance observer was implemented. The simulation experiment results show the performance of system and the resistance to disturbance were improved.