gears based on evidential theory

XING Zong-yi1，YU Xiu-lian1，CHENG Xiao-qing2，QIN Yong1

（1. School of Automation，Nanjing University of Science and Technology，Nanjing 210094，China；

2. State Key Laboratory of Rail Traffic Control and Safety，Beijing Jiaotong University，Beijing 100044，China）

Abstract：Aiming at the problem that traditional methods for fault diagnosis of the metro vehicle running gears depend on single evidence and lead to low accuracy，a new fusion fault diagnosis approach was proposed based on evidential theory. The reason of paradox on the condition of high conflict and low confidence was analyzed，and the combination rule was then modified. All the possible faults of bearings and wheels were collected to construct the frame of discernment for running gears. The diagnosis results of axle vibration， wayside vibration and axle temperature are selected as evidences of fusion diagnosis. The belief function was identified using experts’

experience. The results indicate that the fault diagnosis based on single evidence may lead to low precise or cover few objects，while the proposed fusion fault diagnosis approach based on multiple evidence sources can reach a high accuracy of 80% for bearings and wheels and improve the reliability of fault diagnosis effectively。

Key words：fault diagnosis；metro vehicle；running gears；evidence theory