Integrated Design of Fault Estimation and Fault-Tolerant Control for Closed-Loop Systems With Uncertain Short Delay

In this paper, an integrated design scheme of fault estimation (FE) and fault-tolerant control (FTC) is presented for a closed-loop system with uncertain short delay. Firstly, a closed-loop system with uncertain short delay is modeled as a system with uncertain parameters, and a bi-directional robustness interaction of uncertainty between the observer and the control system is analyzed. Then a fault estimation observer and a fault-tolerant controller are constructed, and the integrated design problem is converted into a robust control problem for the augmented system under $H_{\infty }$ performance index. Furthermore, the parameters of the fault estimation observer and fault-tolerant controller are solved by Lyapunov function and relaxation methods. Finally, the effectiveness and superiority of the proposed method are verified by an aircraft simulation.