Hybrid control of hydraulic directional valves: Integrating physics-based and data-driven models for enhanced accuracy and efficiency

In this paper, we tackle the challenge of accurately controlling the position of the valve spool in hydraulic 4/3 two-stage directional control valves utilized in mobile applications. The pilot valve's overlapping design often leads to a significant dead zone, negatively impacting positioning accuracy and necessitating a sophisticated controller design. To overcome these challenges, we introduce a control strategy founded on a control-oriented model. This model enables systematic compensation for the dead zone, pressure-induced flow fluctuations, and the solenoid's nonlinearities, optimizing the valve's operation for enhanced tracking performance, as verified by test bench measurements. Addressing the limitations inherent in traditional physics-based design methodologies, we suggest approximating the system's primary nonlinearities with a data-driven surrogate model. We propose a solution tailored for systems that rely on minimal sensor information. By merging the advantages of both physics-based and data-driven models, we formulate a hybrid control strategy. This comprehensive approach not only ensures high tracking performance but also has the potential to expedite the commissioning process for new valve variants.