Adaptive Fuzzy Output-Constrained Control of Uncertain MISO Nonlinear Systems With Actuator Faults

This paper presents a novel adaptive fuzzy fault-tolerant controller for a class of uncertain multi-input single-output (MISO) nonlinear systems subject to actuator faults with user-defined time-varying asymmetric output constraints. The highlight of the proposed method is that it can tolerate the partial and total loss of effectiveness faults without the need for additional fault detection and isolation mechanism, as well as remain the system output within the predesigned time-varying output constraints during the system operation. To achieve the new results, an error transformation strategy is implemented to convert the original constrained system to an unconstrained one. For the transformed system, an effective switching function scheme is developed to search for the desired working mode by observing a switching performance index in which the impact of faulty actuators on the system can be weakened automatically. Furthermore, it is proved that the proposed adaptive fuzzy actuator fault compensation scheme can guarantee that the output is confined within the preselected bounds and all the closed-loop signals are bounded. Finally, numerical analysis confirms the merits of the proposed controller. Copyright (C) 2020 The Authors.