Hydraulic spool valve, pilot operated with bi-state switching micro valves is a low-cost alternative to the conventional pilot operated high response proportional valves. However high frequency switching causes variations in the control flow which limits achievable spool tracking error. The paper is to present an analytical model suitable for controller design for spool position tracking of a proportional spool valve, pilot operated by switching micro valves. A nonlinear analytical model of the spool valve is presented. Simulation results from the electrohydraulic proportional valve are presented utilizing state feedback control technique.
