Model and Control Synthesis for an Active Vehicle Suspension Strut Involving a Single-Rod Electrohydraulic Actuator

The paper presents the synthesis of a nonlinear model of a wheeled vehicle suspension strut using an asymmetric (single-rod) electrohydraulic actuator. Due to differences in the active areas of the piston and the nonlinear nature of flows through the throttling orifices of the servo valve, the nonlinear model is characterised by increased complexity relative to systems using symmetric actuators (double rod). The paper covers the results of simulation studies to linearise the model and synthesise a linear quadratic controller based on the linearised model. The derived linear-quadratic controller was utilised to control a nonlinear model of the suspension strut. The control performance of the nonlinear active suspension strut model was compared with laboratory tests of the passive suspension system.