Health Condition Assessment And Maintainance Decision For Metro Vehicle Equipment Units

Metro vehicle is an important part of metro-transit system, and its running safety and operating quality relates to the normal operation of the whole system. Since metro vehicles maintenance work is necessary measures to ensure its running safety、reliability and punctuality, how to improve the efficiency and rationality of its maintenance work is a big concern for metro vehicle maintenance center. For this purpose, this paper studies the problem of health condition assessment and maintenance decision for metro vehicle equipment units, and the main research works and conclusions are as follows:Firstly, based on the analysis of the form and features of metro vehicles’ field data, a discussion of field data collecting and processing method for metro vehicles is made. By adopting a field data collecting framework based on FMEA and making uniform data collecting procedures and standards, the field data collecting quality is guarantee, and by making rational assumptions and determining the rational statistical samples for data processing, the foundation for getting the reasonable data analysis results can be laid.Secondly, a discussion of health condition assessment method for metro vehicle equipment units is made. By introducing combined fault mode severity and integrating it with fault rate、fault detection rate and relative-deterioration degree as evaluation indexes, an assessment framework for health condition assessment of metro vehicle equipment units is established. And based on AHP and FCE method, a health condition comprehensive assessment model for metro vehicle equipment units is constructed, which can make assessment on the analytic level of the units composing the equipment equipment functions and the whole equipment. A case study of a pantograph number 4182 of a certain metro vehicle is also given, and the assessment result reflects the reality preferably, proving the rationality of the assessment model which can provide some suggestions for condition based maintenance of metro vehicles.Thirdly, analysis on maintenance decisions for metro vehicle equipment units is made. A method based on FMECA and criticality matrix for key maintenance objects and points determining, as well as a method for maintenance modes decision making based on RCM logic decision principle are discussed. By taking probabilistic risk of metro vehicle online operation fault as basis for decision making, an inspection interval decision making model based on DTM is constructed and a periodic replacement time decision making model based on NHPP is proposed for metro vehicle equipment units. The case study results of the two models reflect the reality preferably, demonstrating their validity in providing suggestions in metro vehicles’ maintenance decision making. By taking metro vehicle operation availability as basis for decision making, on the basis of analyzing the model for calculating the spare number of irreparable equipment units, a model for calculating the spare number of metro vehicle repairable equipment units based on HPP and non-homogenous markovian process is proposed. With its validity proved by a case study, it can provide some suggestions for metro vehicle maintenance decision making.Fourthly, a discussion of comparison and rationality assessment of different metro vehicle maintenance schemes is made. By comparing maintenance effectiveness evaluated by assessing metro vehicles’ operation reliability、availability and maintenance cost under different maintenance schemes, the rationality comparison of different maintenance schemes is achieved. In order to reduce the interference caused by the random variability of metro vehicles on the comparison, based on RCB design principle a comparison scheme is proposed and ANOVA is used to identify the significance of the difference between different maintenance schemes, thus providing objective precise references for the final determination of metro vehicle maintenance scheme.