Robust Stabilization of a Class of Unmatched Uncertainties Nonlinear Systems

The paper presents a smooth and simple robust tracking controller for a class of nonlinear systems with unmatched uncertainties. The designed controller can be the concrete expression including no Lyapunov functions and no norm computing in each step of control and can suppress forwardly the influence of uncertainties. The practical stability of output tracking error and the states of the corresponding closed-loop system are demonstrated by Lyapunov stability theorem. Finally, an illustrative example is given to demonstrate the utilization of the approach developed.