Research On Condition Monitoring And Maintenance Decision Of APU System

Auxiliary Power Unit(APU)is an integral and important system in aircraft,The failure and use of APU will have an important impact on the safety and use of aircraft,Especially for some airports with high turnover or shortage of ground support facilities,it will lead to flight delays directly.Compared to the aero engine,Because of the relatively low security of APU,many airlines have not paid enough attention to APU,It is still based on the use of restorative and scheduled maintenance,The advantages of advanced monitoring technology and health management have not been fully developed.The cost of maintenance for every flight hour of APU is high,and it almost reaches the maintenance cost per flight hour of the aero engine.Therefore,this paper predicts the APU lifetime by monitoring the state parameters of the APU system.And through the reasonable issued and maintenance decision-making,to ensure the safety of APU,while improving their economic purpose.To this end,the main work of this paper is to be carried out in the following aspects:First,By consulting and analyzing the research status of state monitoring and life prediction technology and maintenance strategy at home and abroad,the difficulties and shortcomings of APU life prediction technology are summarized.Secondly,APU performance monitoring data research to obtain an airline fleet,based on the data obtained from the performance analysis,using multiple imputation method,inspection and test method of Nair Grubbs data fill and exception handling,through case analysis and verify the validity of data pretreatment method.Thirdly,According to the present forecast method based on single parameter engineering to meet the complex system of APU life prediction demand situation,remaining life prediction method of APU proportional hazard model based on the APU,and the performance of a airline fleet degradation as an example to verify the analysis,results show that the fusion method of multi parameter proportional hazard model based on prediction with high precision.Then,The remaining life prediction based on the APU,set up maintenance decision model of APU with minimal maintenance costs as the goal,to optimize the decision time point of APU repair,maintenance play advantage,reduce the maintenance cost of APU.The example indicates that the maintenance decision model is proposed to predict APU repair time accurately,saving APU excessive and deficient maintenance caused by additional costs,and effectively guarantee the safe operation of the system.Finally,according to the above research results,based on the GUI technology of MATLAB,the APU condition monitoring and maintenance decision management system is developed,and verified by engineering examples.