Research On Fault Diagnosis Method Of Flight Control System Based On Graph Theory

There are many problems in fault diagnosis process of flight control system, such as multiple influencing factors of causing fault, multiplicity of symptom, complex correlation among faults and so on, and the realationship between cause and symptom of fault is inexplicit. So in the diagnosis process, the fault sources can be located effectively only when the fault propagation characteristic among the different sub-system.The model of Direction Graph(DG) can express complicated cause-effect relationship,has the capacity of containing large-scale potential information and good completeness in the process industrial system. On the basis of summarizing the existing literatures of fault diagnosis, this paper mainly researches some difficulties and key technologies, such as DG modeling, DG reasoning rules, DG node selecting and so on. The above research works improve the system of graph theory and fault diagnosis method. And according to the characteristic of flight control system, DG is presented to apply in fault diagnosis of flight control system.On the base of comparing the current methods of fault diagnoses in control system, the thesis puts forward the DG model to analysis the flight control system; Then describes the establishment of the direction model and the algorithm of the fault orientation, also puts forward the using of relation algorithm to array the fault sources on the base of the experiences accumulated by the airlines for many years; Then introduces the principle of the flight control system, combining its technology feature and fault type, giving an example to set up the direction graph model of aileron, orientate and array the fault.By theoretical analyses and case studies, it shows that the DG can describe the airborne electronic system principle completely and effectively with computer, and it is convenient to add the expert experience knowledge. The DG not only combines the merits of expert and the principle but also conquers the shortage of them, then improves the maintenance efficiency.