A VARIABLE-STRUCTURE CONTROL WITH PROPORTIONAL AND INTEGRAL COMPENSATIONS FOR ELECTROHYDRAULIC POSITION SERVO CONTROL-SYSTEM

Electrohydraulic servomechanisms are widely used in manufacturing mach inery, in the heavy-duty machine and automobile industry, because the hydraulic control systems can provide large torque and higher speed of response with fast motion to the plant. However, highly nonlinear and parameter uncertainties mean that the control of the hydraulic system is not always optimum. In this paper, we apply the technique of varia ble structure control with proportional and integral compensations (PI VSC) to an electrohydraulic position servo control system. The numeric al simulation result shows that PIVSC has faster output response than the integral variable structure controller (IVSC) and zero steady-stat e error with external disturbance to the nonlinear plant. (C) 1997 Els evier Science Ltd.