Adaptive Tracking Control for a Class of Nonlinear System with Mismatched Uncertainties

The problem of robust adaptive tracking for a class of mismatched uncertain nonlinear systems is discussed. Under the assumptions of uncertain system model and unknown parameters, combining backstepping design with robust control technology, a robust output feedback control scheme and an adaptive parameter control law is developed for unknown parameters and dynamic uncertainties. It is proved that the derived robust adaptive controller based on Lyapunov stability theory can guarantee global uniformly ultimate boundedness property for all states of the closed system, and lead to tracking error at exponential speed to a small. Compared with the classical adaptive backstepping procedure, it allows the nonparametric uncertainties in the last equations of the systems. The robustness of the closed loop system is enhanced. In order to demonstrate the effectiveness of the developed novel controller, an example is extensively simulated to provide quite satisfactory performance