Adaptive robust control of a high-response dual proportional solenoid valve with flow force compensation

This article focuses on the high-performance control of a high-response proportional solenoid valve which has two proportional solenoids. The valve is named high-response dual proportional solenoid valve (HDPSV). The HDPSV can achieve faster response than other high-response proportional solenoid valves with one proportional solenoid and has the potential of gaining stronger disturbance rejection due to the differential effect of two proportional solenoids. However, the expense for these advantages is that more complexity and more difficulties are involved in controlling the valve. In this article, the nonlinear dynamic model of the HDPSV is constructed first. The current–force gain of the proportional solenoid is modeled by a modified tanh() function to capture its nonlinear characteristics. An incremental differential allocation strategy is raised to coordinate the action of the two proportional solenoids driving the HDPSV. The model of flow force is built with parametric uncertainty and reconstructed to address its non-differentiability. To deal with the parametric uncertainties and uncertain nonlinearities appearing in the dynamic model of the HDPSV discontinuous projection-based adaptive robust control, which combines systematically backstepping adaptive control with deterministic robust control, is extended to synthesize HDPSV controller. Simulations and experiments are carried out to validate the effectiveness of the controller. Both the simulation and experimental results show that with the proposed adaptive robust controller, the flow forces are well compensated, while the HDPSV achieves disturbance rejection, high precision, fast transient response and broad bandwidth.