Abstract: A method of design of observer is presented for fault detection and isolation when the parameters of the control system are changed. In this method of design the eigenstructure assignment is used for observer. In order to isolate the fault of each sensor channel, a parity subspace of the error between the system output and observer output is constructed, and the faults of each sensor are decoupled in the parity subspace. The detection and isolation of the fault of each sensor are realized, where only one observer is used. Thereby the robustness of the fault detection and isolation is achieved.

Key words: faults-detection, robustness, sensor