Adaptive Robust Control for Nonlinear Systems with Mismatched Uncertainties

In this paper, the adaptive robust output tracking problem for a class of nonlinear systems which have both mismatched uncertainties and matched uncertainties has been addressed. The nominal system is input-output linearizable. Based on the input-output linearization technique and Lyapunov approach, an adaptive control law is developed to track the bounds on the plant uncertainties so that no prior knowledge of the bounds is required. It is shown that the output of the closed-loop systems ultimately track the desired output with a bounded tracking error despite the system uncertainties. An example is performed to illustrate the effectiveness of the proposed control scheme.