Adaptive fuzzy fault tolerant tracking control for a class of uncertain switched nonlinear systems with output constraints

This paper studies the adaptive fuzzy fault tolerant tracking control problem for a class of switched multi-input multi-output (MIMO) nonlinear systems with output constraints under arbitrary switchings. The actuator faults under study consist of unknown stuck and loss of effectiveness. In the design procedure, the unknown control signals are approximated directly by fuzzy logic systems. To prevent constraints violation, a tan-type barrier Lyapunov function is incorporated into the Lyapunov function design. Based on the idea of estimating the bound on switching parameters, a novel adaptive fuzzy fault tolerant tracking control technique for the problem studied is set up by exploiting the common Lyapunov function method and backstepping. It is shown that under the proposed control law and adaption rules, all the signals remain bounded and the system output tracking error can be guaranteed to exponentially converge to a neighborhood of origin, while the constraints on the system output will not be violated during operation. Finally, simulation results are presented to show the effectiveness of the proposed approaches.