Fault Diagnosis for Actuator of Aero-Engine Based on Associated Observers

Aero-engine is a high safety requirement systems, thus the consequences of actuator faults are often extremely serious. Considering the robustness and fault detection rate at the same time, the existing fault diagnosis schemes are not optimal. In order to achieve this, a fault detection and isolation scheme is proposed based on associated observers integrated by sliding-mode observer (SMO) and luenberger observer (LO). Firstly, the original system is converted into two parts. One consists of system uncertainties while the other not. Then, for fault detecting, a SMO is designed to eliminate the uncertainties while a LO is constructed to detect faults. Moreover, for fault isolation, a group of SMOs are constructed. Each is only sensitive to the certain type of fault. After that, the newly designed fault diagnosis scheme for actuator of aero-engine is verified in detail. It can be seen from simulation results that the effect of uncertainties is eliminated and a small threshold can be selected. Thus, the robustness and high fault detection rate can be guaranteed at the same time. In conclusion, this scheme possesses certain application in practical engineering.