Research On Comprehensive Decision Of Aircraft Power Distribution System Auxiliary Troubleshooting Based On Expert System

The rapid development of aviation industry and air transport industry leads to accelerated generation change of aircraft models and rapid expansion of the airlines' fleet,which leads to the difficulty of fault isolation and maintenance workload increased.It is a difficult problem faced by airline maintenance that how to confirm the key fault information quickly,improve the fault disposal efficiency,reduce the impact on the normal operation of flights,reduce the maintenance cost.In traditional airline fault disposal mode,maintenance personnel make the troubleshooting solution mainly by maintenance manuals and estimate fault disposal time temporarily,with the inadequate use of the maintenance experience and historical fault data.That lead to a low efficient troubleshooting and insufficient support to flight operation decision,result in a long time flight delay or flight change frequently in case of airplane fault.This thesis conducts the research on the above issues,and the main research contents are as follows:This thesis summarizes and analyzes the research status of aircraft fault diagnosis and auxiliary troubleshooting in China and abroad.Then studies on the common fault diagnosis and analysis methods of aircraft,especially on the fault tree analysis method and expert system method,and applies them in the fault analysis and auxiliary troubleshooting comprehensive decision-making of the power distribution system in this thesis.In this thesis,the composition structure and the function and principle of the key components of the power distribution system are analyzed.Based on the demand of airline maintenance,the fault tree analysis method was used to analyze the fault mode of the key LRU of a certain type aircraft power distribution system,and the fault tree was established.The aircraft system was simplified according to the aircraft system function block diagram and the basic control theory,to judge the priority of fault information processing easily.At the same time,the fault is divided into nuisance fault and real fault,which is convenient to calculate the priority order in the troubleshooting decision logic.Based on the expert system theory,this thesis proposes a comprehensive decision solution for aircraft power distribution system auxiliary troubleshooting.By combining the fault history(three-year rolling data)with the maintenance troubleshooting manual,the weighted priority order of troubleshooting is determined,then use the maintenance experience as supplement,so that the troubleshooting plan is closer to the actual situation of the aircraft fleet.At the same time,as to improve the efficiency of the fault information prediction,the judgment logic of the singleness,relevance and the superior and subordinate relationship ofthe key fault information prediction were put forward.In addition,as to provide a basis for the time evaluation of the aircraft dispatch with fault deferral or troubleshooting,the average dispatch work time and average troubleshooting work time parameters are introduced,and constantly revised according to the calculation method of industrial working hours.In order to improve the support to flight operation,the comprehensive decision-making logic is proposed innovatively,and the traditional decision-making logic of troubleshooting and aircraft dispatch with fault deferral are optimized.Finally,the auxiliary troubleshooting comprehensive decision-making logic is verified through the fault cases of the distribution system.And the practical value in improving the fault handling efficiency,saving maintenance cost and improving the operation decision support is proved by compared with the actual fault disposal scheme and results.The comprehensive decision making logic is worthy of being popularized in other civil aviation aircraft systems.