Command-filter-based adaptive fault-tolerant tracking control for nonlinear systems with mismatched disturbances

Abstract

The adaptive fault-tolerant tracking control problem is considered for uncertain nonlinear systems with actuator fault and mismatched disturbances. The derivatives of the desired signal are not required, and the bounds of the disturbances and control coefficient are also unknown. First of all, a finite-time differentiator is utilized to track the desired signal and its derivative. Besides, a smooth function is introduced in the virtual controller to eliminate the effect of the mismatched disturbances. And then, an adaptive tracking controller is designed by combining backstepping technique and command filter scheme such that the problem of “explosion of complexity” can be solved. Moreover, it is proved that all the signals in the closed-loop systems are bounded and the tracking error can asymptotically converge to zero. Finally, a simulation example is provided to show the effectiveness of the proposed controller.