Adaptive output feedback tracking of nonlinear time-delay systems with uncertain dead-zone input

This paper investigates the problem of adaptive practical tracking via output feedback for a family of uncertain nonlinear systems with time delays and nonsymmetric dead-zone in actuator. Instead of the dead-zone inverse method, an adaptive output feedback robust control scheme is developed by extending the high-gain observer. To deal with the dead-zone nonlinearity, we combine the dynamic high-gain scaling approach and one-step Backstepping method. With the help of Lyapunov-Krasovskii functional, one proves that all closed-loop signals are bounded, while the system output tracks a broad class of bounded and time-varying reference trajectories by arbitrarily small error prescribed previously. Finally, a numerical example is given to illustrate the effectiveness of our controller.