Study On Fault Diagnosis System Of AC17 Model Vehicle Based On Fault Tree

With the rapid development of the city, more and more people choose metro as a travel tool. The operational safety of the metro system has attached more attention. As direct carrier, the safety of metro vehicles directly influences the life safety of the passengers. With the increasing of the complexity and operational time of the train equipment, the probability of failure is also increased gradually. When the vehicle components occurs failure, it will affect the normal operation. Therefore, how to diagnose the components fault of metro vehicle rapidly and efficiently is an important issue to be resolved.In this paper, in view of the AC17 model vehicle of Shanghai metro line 2, the fault condition of the train is analyzed firstly, and the troubleshooting process of vehicle components is introduced. Through the study of the logic relationship of components in comprehensive wiring diagram, combining with the technical documents such as failure cases、contingency plan etc, the failure phenomena of components are classified and summarized.Secondly, the principal of fault tree analysis is studied, and the characteristics of fault tree analysis and the step of establishing fault tree are also introduced. Based on the theory, the fault tree of components fault phenomena is constructed and the minimal cut sets are computed by Fussell-Vesely method. By analyzing the characteristics of minimal cut sets, the sequential table for troubleshooting is obtained. Because of the same sequence of some cuts, a new method combining the data of failure cases and the sequential table is proposed.Finally, a fault diagnosis system for AC17 model metro vehicle based on VB6.0 and Access software is designed. The system design diagram and the structure of knowledge base are also described. Furthermore, the operation process of the modules is introduced and a method of VB accessing database is designed. System operational interface is presented. Two practical examples show that the fault diagnosis system can diagnose the fault quickly, summarize the diagnosis results, and improve the efficiency of fault diagnosis.