Research On Fault Diagnosis Expert System Of Aircraft’s Wheel Braking System

As a key system to ensure the safety of aircraft take-off and landing,the performance of wheel brake system has a great impact on flight.If the wheel brake failure occurs during aircraft landing,the consequences are unimaginable.Therefore,it is necessary to diagnose the faults of wheel brake system timely and accurately to ensure its normal operation.It is very meaningful to study the fault diagnosis expert system of wheel braking system.This article first introduces the development process of fault diagnosis technology and expert system,and puts forward the improvement direction of fault diagnosis expert system,then introduces the working principle,overall structure and each modules of the expert system.Starting from the working principle of the wheel braking system and the functions of the main components,combined with the daily maintenance work experience,three types of typical faults are selected for detailed analysis.The fault tree analysis method is used to construct the fault tree respectively in principle,carry out a qualitative analysis,systematically show the logical relationship from the fault phenomenon to the fault cause,obtain the minimum cut set of the fault tree,and sort out the fault knowledge such as the cause of the fault and the troubleshooting method.In a similar way,book knowledge and enlightening knowledge are collected extensively.On this basis,the framework structure of the expert system is determined,and the knowledge base,inference engine,explanation mechanism and human-machine interface module are designed.The first two modules are the most critical to the system.Because the fault knowledge of the wheel braking system has the characteristics of causality and progressive layer by layer,the production rule representation method is preferred to complete the knowledge representation,and the fault knowledge is converted into fault rules to narrow the search scope and provide the working efficiency of the system.According to the top-down structure of the fault tree,the forward reasoning strategy is selected to match and query the user input information with fault rules.In addition,considering the user’s technical level and usage habits,the inference process is designed in two ways:inquiry-based and selection-based.The overall implementation process of the expert system is planned,the fault knowledge rules are built into the knowledge base by using Access software.Visual Basic 6.0 language is used to realize the inference machine and human-machine interface,and connecte the knowledge database to achieve access and other functions.The expert system is finally developed.The system has three main functions,such as knowledge base management,selective fault diagnosis and inquiry fault diagnosis.Different diagnosis functions can meet the needs of users with different usage habits.In addition,the knowledge base management such as adding,deleting and modifying can be performed as required.After functional test and typical fault verification,it shows that the fault diagnosis expert system meets the design requirements.The knowledge in the system is equivalent to experts,which can complete a more comprehensive fault diagnosis work and improve the troubleshooting efficiency fairly.The system has a friendly operation interface,perfect diagnosis function and conveniently to maintain.