Model-based fault detection and isolation design for flight-critical actuators in a harsh environment

Safety-impact on flight-critical systems such as flight or engine control systems is a major concern for aircraft equipment designers in civil and military fields. Current avionic equipments related to safety-critical systems are able to detect trivial faults such as loss of power, short circuits, open circuits or threshold overflow. The occurrence of these faults in actuator control loops, if detected, triggers a fail-safe mode. So, although system availability is reduced, the required safety level can still be ensured. This paper emphasizes a design methodology of nonlinear model-based FDI1 algorithms applied to a Hybrid Stepper Motor (HSM). The proposed design methodology combines a nonlinear dynamic inversion and residual generation using standard continuous Kalman Filter. The proposed fault detection method is based on residual mean-checking analysis, where the parameters are tuned with Kriging method.