Self-sensing actuators in electrohydraulic valves

Self-sensing refers to extracting the position information from the electromagnetic signals instead of from a physical position sensor. Self-sensing actuator has the benefit of significantly reducing hardware effort. In this paper, we investigate selfsensing actuators applied in direct acing proportional valves. The study is based on the configuration of a dual-solenoid actuator where each solenoid provides the independent single direction force. By considering the electrical dynamics of the solenoids and the nonlinear constraint between the two solenoids, an observer for the flux linkages is obtained. The position estimate is then calculated based on the flux linkage estimates. Both simulation and experiments verify the validity of the proposed algorithm.