A stable robust adaptive controller for a class of nonlinear systems

In this paper, a robust adaptive control is proposed for a class of nonlinear systems subject to unmodeled dynamics and bounded disturbances. The nonlinear systems are represented by their input-output maps. The e1-modification scheme is proposed to achieve robustness and enhance the convergence properties of the tracking error in the absence of disturbances. The stability of the closed-loop system is shown by Lyapunov´s direct method. Simulation results demonstrate the improved performance of the proposed controller as compared with the previously reported adaptive controllers in the literature.