AN ADAPTIVE PRESSURE CONTROLLER DESIGN OF HYDRAULIC SERVO SYSTEM WITH DEAD ZONE

抄録

This paper develops a design of adaptive pressure controller for hydraulic servo valve with unknown dead zone. In general to reduce leakage flow, the servo valves adopt positive lap structures. This makes dead zone larger and is obstacle for precise positioning control. To compensate of such dead zone and unknown physical parameters of system, adaptive control strategy is examined for simple pressure control system. First it is assumed that only the flow gain of servo valve can be known by experiment and the adaptive controller is designed. This controller is examined on water hydraulic servo system which has larger leakage and positive lap for lower viscosity of tap water. The experimental results show that the better tracking performance is obtained comparing with PI or conventional adaptive controller without dead zone compensation. Then the controller is extended for unknown flow gain case.