Robust Fault-Tolerant Control Based on L∞ Design for Discrete-Time Systems With Parameter Uncertainty

In this letter, a robust fault-tolerant controller is proposed for discrete-time systems with parameter uncertainty. First, the state and fault are estimated by an observer based on the $L_{\infty }$ design. The stability of the $L_{\infty }$ observer is proved and the error system is robust against unknown disturbances. Then, on the basis of fault and state estimation, $L_{\infty }$ technique is applied to design the robust fault-tolerant controller to recover the performance of the system affected by the actuator fault. Based on the proposed method, the compensated state can be bounded by the designed $L_{\infty }$ index, which guarantees the safety of the system. Finally, the proposed robust fault-tolerant controller is applied to the simulation of a dual-rotor aero-engine system model, and its effectiveness is verified.