Study of robust tracking control for a class of nonlinear systems

A smooth and simple robust tracking controller is presented for a class of nonlinear systems with unmatched uncertainties and a strong relative degree in the paper. Using the technique of feedback linearization and Lyapunov approach, the designed controller can suppress forwardly the influence of uncertainties. Meanwhile, there is no Lyapunov functions in controller but concrete controller expression instead and no norm computing in each step of control. The practical stability of output tracking error and the states of the corresponding closed-loop system are demonstrated by Lyapunov stability theorem. A simulation results demonstrate the effectiveness of the proposed approach.