The Trajectory Tracking of an Electrohydraulic Servo-Mechanism via a Sliding Mode Controller

Abstract

Since hydraulic power systems possess such features as high output power per unit weight, high acceleration capability and high torque stiffness, they are the most common form of precise power manipulation. In addition, the bandwidth of electrohydraulic servo-mechanisms is higher than that of pump control systems and thus they are more commonly used at present. However, some non-linear phenomena (for example stiction of cylinder, deadband due to internal leakage, fluid compressibility) make the precise microtrajectory tracking of an electrohydraulic servo-mechanism difficult. Because of the essential advantages of sliding mode control (fast response without, or with a little, overshoot, lower sensitivity to parameter variations and simple realization) a discrete-time servo-controller via the sliding mode technique is implemented to track a non-periodic trajectory.