A new control method for uncertain nonlinear systems tracking control

A new control scheme is proposed for a class of nonlinear uncertain time-varying systems tracking control. The proposed controller combines advantages of both robust and adaptive control schemes. Unlike the traditional robust control scheme, the proposed controller does not require to know the structure of uncertainties, but can still ensure the asymptotic stability of the closed-loop system. Comparing with the traditional adaptive control scheme, this controller can deal with time-varying parameter uncertainties, and the uncertain parameters do not need to be a linear function of the states. The stability analysis of the closed-loop system is performed based on the newly developed theory presented in this paper. An experimental result on a positioning table is presented for illustration