Research On Simulation For Fault Diagnosis Of Aeroengine Digital Control System

It is inevitable to apply Full Authority Digital Electronic Control(FADEC) in the control systems of modern aeroengines, and high reliability is the key element for FADEC system application. To increase the reliability of FADEC system, the technique of sensor Faults Detection, Isolation and Accommodation(FDIA) was studied in this paper, also the real-time simulation validation was carried out in Matlab/Simulink/RTW(Real-time Workshop).Firstly, the linearization technique of a turboshaft engine was analyzed in this paper, then large perturbation state variable models were established for simulating the accelerating process and the decelerating process. The turboshaft engine model was also established successfully in Simulink.According to Kalman filter and multiple-failure-hypothesis based testing, two banks of Kalman filters were designed respectively, one for single sensor fault , and the other for multiple sensor faults. Then the ability of estimating states, the stability, the robustness and the observability of the constant gain Kalman filter were tested. Digital simulation demonstrates that the method used here for fault diagnosis is feasible.In order to connect the computer for engine model and the control computer with the signal interface emulator on the platform for fault diagnosis, some modes which perform serial communication in Matlab were presented. Then user-written custom device drivers of serial port and PCI1780 which were used with real-time windows target were programmed respectively at the register level.Finally, an integrated system of sensor FDIA was designed in Simulink. All kinds of sensor faults were set up in the control computer. Simulation experiments which include the signal interface emulator were developed for validating the performance of the FDIA system. Experimental results show that the FDIA system can detect single or multiple sensor faults in time, and provide good analytical redundancy.