Backstepping tracking control for a class of uncertain nonlinear systems

In this paper, a novel direct adaptive tracking control scheme is presented for a class of nonlinear systems with unknown virtual control coefficients. Based on the Lyapunov stability theory, a direct adaptive tracking controller is developed by using the backstepping approach. The proposed design scheme guarantees that the tracking error converges to an arbitrarily small neighborhood of the origin. Comparing with the classical adaptive backstepping procedure, the robustness of the closed-loop system is enhanced. Finally, simulation examples are used to demonstrate the effectiveness of the proposed control scheme.