Robust fault diagnosis method of flight control system based on disturbance decoupling assignment

The observer of fault detection and diagnosis is designed based on disturbance decoupling assignment aimed at flight control system having unknown input disturbances. It makes residual in quadrature with disturbances distributed direction through left eigenstructure assignment to observer. The transfer function is zero between fault detection residual r and unknown input disturbance d. So it makes residual decoupling and robust with disturbance. The fault diagnosis and isolation algorithm is not influenced by the system uncertain disturbances. The reliability and precision of fault diagnosis are improved. Meanwhile it can identify faults shape online through residual estimating faults. The simulation results verify method validity.