Robust adaptive outgulation for a class of nonlinear systems with uncertain gain

This paper focuses on global stabilization and disturbance suppression of a class of nonlinear systems with unknown high-frequency gain and nonlinear exosystem by using adaptive backstepping output feedback control approach. Using the designed observer of state estimation, and combining the adaptive control with backstepping approach, an adaptive backstepping control scheme is proposed. By appropriate choice of the design parameters of the proposed control design for output regulation, the closed-loop system is proven with the observer errors and tracking error converge to an any small neighbourhood of the origin.