Robust adaptive output-feedback control for a class of nonlinear systems with hysteresis compensation controller

In this paper, a robust adaptive output-feedback dynamic surface control scheme is proposed for a class of single-input single-output nonlinear systems preceded by unknown hysteresis with the following features: (1) a hysteresis compensator is designed in the control signal to compensate the hysteresis nonlinearities with only the availability of the output of the control system; (2) by estimating the norm of the unknown parameter vector and the maximum value of the hysteresis density function, the number of the estimated parameters is reduced, which implies that the computational burden is greatly reduced; (3) by introducing the initializing technique, the initial conditions of the state observer and adaptive laws of unknown parameters can be properly chosen, and the arbitrarily small L norm of the tracking error is achieved. It is proved that all the signals in the closed-loop system are ultimately uniformly bounded and can be arbitrarily small. Simulation results show the validity of the proposed scheme.