Adaptive disturbance observer-based control of hydraulic systems with asymptotic stability

Abstract

As control precision is the most important indices of control precision, this study concerns with high accuracy tracking control of hydraulic systems. We suggest an adaptive disturbance-observer-based asymptotic tracking control strategy to hydraulic systems for achieving our motivation. It is of note that parameter uncertainty and disturbance are challenges in the area of hydraulic system control. In this study, the time-varying disturbance is compensated by model-based feed-forward control terms which are designed by a sign of error-function-based disturbance observer. To avoid the high learning burden of the disturbance, which is resulted from the parameter uncertainty, online adaptive control is integrated with the mentioned disturbance observer. To guarantee the theoretical feasibility of the proposed controller, the stability analysis Xis accomplished by introducing the Lyapunov stability theory. Compared with previous works reported in the literature, the proposed adaptive disturbance observer-based a controller can achieve global asymptotic stability when the considered systems are subjected to mismatched or match disturbance. The comparative experimental results reveal that the proposed method can obtain state-of-the-art tracking performance for hydraulic systems under the influence of parameter uncertainty and time-varying disturbance.