Disturbance observer‐based adaptive fuzzy control of nonlinear electrohydraulic proportional systems with dead zones

This paper introduces a class of adaptive fuzzy control approaches for high‐performance motion control of electrohydraulic proportional systems subject to uncertain models, external disturbances, and dead zones. Compared to existing research, a non‐smooth dead zone model with potential discontinuities is considered, and the controllable region is nonlinear with uncertainties, which implies a more challenging control design. Multiple fuzzy approximators are employed for detailed estimation to improve system robustness. Discontinuous disturbances and modeling errors generated by the fuzzy approximators are partially compensated by an innovative adaptive term. A disturbance observer‐based adaptive fuzzy backstepping controller (DO‐AFBC) is developed to resist more general disturbances and exhibits a superior dynamic response compared to traditional control methodologies. A Lyapunov proof is provided to guarantee that all system states are semi‐globally stable. Through an analysis of conservativeness, a modified method is proposed to further enhance the design. Finally, simulation results demonstrate the effectiveness and high accuracy of the proposed scheme.