An Alternative Nonsmooth Adaptive Output Regulation Strategy for Nonlinear Systems with Mismatched Disturbances

In order to release the "over conservativeness" brought by existing robust output regulation approaches, this paper proposes an alternative dynamic exact tracking controller in a novel non-recursive manner for a class of nonlinear systems subject to mismatched disturbances. One key feature of this paper is that the self-tuning scaling gain in the composite controller can adaptively adjust to the most suitable value for the current operating condition by means of an online update mechanism. Therefore, the control system is able to achieve a balance between robustness and adaptivity, in order to obtain an improved transient-time control performance. The effectiveness of the proposed method is validated by a three-order numerical example.