Study On Fault Characteristic Analysis And Fault Diagnosis Technology Of Aircraft Hydraulic System

The safe operation of aircraft hydraulic system is one of the important conditions to ensure the flight safety,by recording the fault from ARJ21 aircraft in recent years,we can realize that there exist some potential problems in aircraft hydraulic system failure safety,and it has the possibility of the leakage of all the hydraulic oil in the air and will have a strong impact on the reliability and safety of aircraft operation.In this thesis,based on the analysis on the fault risk type of the hydraulic system and its main influence factors,it conducts detailed analysis and discussion of the effect of ARJ21-700 hydraulic system fault features,categories as well as all kinds of influencing factors(including internal use factors and external environment factors)to the state and reliability of this type of aircraft hydraulic system.The main research contents are as follows:On the basis of the collection&classification analysis on the operation information and a large number of historical failure cases of the hydraulic system of the ARJ21 aircraft,it analyzes the main type of fault risk and their mutual logical relations in the process of hydraulic system,establishes the tree models of fault,proceeds qualitative and quantitative analysis and determines the main factors affecting hydraulic system safety.The paper studies the real-time warning and treatment method of hydraulic system fault risks.By collecting and analyzing the historical data,monitorin,g parameter and threshold value of hydraulic system’s monitoring system,it researches the decision information system structure,discretization method and attribute reduction algor,ithm of discernible matrix&value reduction bases on rough set theory;establishes the method to obtain the warning decision rules of hydraulic system;Taking the hydraulic system of this aircraft as the main study object,by implementing the attribute reduction and rule extraction,it analyzes the hidden trouble cause of the fault in all aspects and proposes corresponding countermeasures.Hydraulic system fault characteristics of this type of aircraft are comprehensively analyzed.Based on the daily maintenance requirements for manual inspection of fault hidden dangers,the symptoms,reasons and corresponding countermeasures of fault potential dangers are studied.The manual treatment method of fault potential dangers based on symptom are established.In order to strengthen daily management and reduce the occurrence of security risks,the manual inspection and management mechanism of hydraulic systems are set up.In the process of fault diagnosis of aircraft hydraulic system,the fault recognition established by maintenance staff based on working principle and working experience,then converted them into the concept of"membership"by introducing the method of fuzzy mathematics,which is then quantified to establish the mathematical model of fault diagnosis,and the most likely fault point is found by further calculating.