Adaptive backstepping control of nonlinearly parameterized systems with time-varying disturbances

We consider global adaptive control of nonlinearly parameterized systems in parametric-strict-feedback form with uncertain time-varying disturbances in this paper. We do not require a priori bounds on the unknown parameters, which is as in the linear parameterization case. We also allow unknown parameters to be time-varying provided they are bounded. Our proposed adaptive backstepping controller is a switching type controller, in which the controller parameter is tuned in a switching manner via a switching logic. Global stability results of the closed-loop system have been proved.