Adaptive Fuzzy Disturbance Observer-Based Control for Nonlinear Uncertain Systems with General Exogenous Disturbances

This paper considers one kind of nonlinear uncertain system which is disturbed by general external disturbance generated by an exogenous system. The partial known information of the external disturbance will be efficiently applied to construct an adaptive disturbance observer (DO) for estimating the unknown external disturbance. The nonlinear uncertainties are also considered in this paper, and the fuzzy logic systems are applied to approximate the nonlinear uncertainties. An active disturbance rejection fuzzy controller is designed based on the proposed DO, under which the tracking error will converge to a very small neighborhood of the origin by designing the proper parameters. Moreover, under the disturbance observer-based (DOB) controller, the nonlinear system is anti-disturbance and robust to the uncertainties. The author also proves the effectiveness of the presented approach by the simulation.