Observer-Based Robust H ∞ Fault-Tolerant Control for T-S Fuzzy Fractional-Order Systems With Multiple Faults and Disturbances

The robustH∞fault-tolerant control problem for a class of nonlinear fractional-order systems described by T-S fuzzy models is investigated in this paper. A transformed system is firstly constructed according to the original system. Then, a fractional-order intermediate observer is proposed. It can obtain the state and actuator fault of the transformed system, which indirectly achieves the simultaneous estimation of states, faults and disturbances of the original system. Unlike the strategy of suppressing or decoupling the disturbances in traditional fault estimation methods of nonlinear fractional-order systems, this paper focuses on estimating the disturbances directly. This way not only avoids handling the disturbances or the dynamics of faults via theH∞method, but also does not have strict equation constraints required in the decoupling method. Additionally, an active fault-tolerant controller is designed that dynamically adjusts its actions based on the information obtained by the observer, thereby ensuring system stability under multiple faults and disturbances. Finally, the effectiveness of the proposed method is validated on two typical application circuits.