Discrete sliding mode controller for pressure control with an electrohydraulic servovalve

Abstract

Electrohydraulic servovalves are the most commonly used control devices for hydraulic systems and are difficult to control because they are in essence highly nonlinear. In this study, a discrete time sliding mode controller is designed to control the pressure drop across a load. A nonlinear transformation is presented to convert the system dynamics to a linear state space representation. The performance of the controller is numerically analyzed and compared to a classical PID controller.