Reliability Analysis And Evaluation Of CBTC System In Urban Rail Transit

The train control system is born and developed in order to ensure the safety of transportation,so it is the core technology and key equipment to ensure the safety of driving.As a large capacity and high density public transportation,the urban rail transit system must have a set of safe and reliable train control system.Otherwise,if the system fails,it will crisis the train safety and cause the loss of personnel and property.This thesis takes the Communication Based Train Control(CBTC)as the research object,dynamic fault trees analysis(DFTA)and cloud model are adopted to analyze and evaluate its reliability.According to the structural characteristics of the CBTC system,in view of the shortage of traditional fault trees in reliability analysis,this thesis uses DFTA to analysis CBTC system.Firstly,dynamic fault tree models are established by analyzed the structure and function of the CBTC system.Secondly,the depth-first left-most(DFLM)is used to decompose the DFTA into several static and dynamic modules.Static modules are analyzed by binary decision diagram(BDD),and dynamic modules are analyzed by Markov.Finally,the results of module synthesis are used to show that CBTC system meets the requirements specification and identify the weak links of the system,and the appropriate use of redundant can improve the reliability of the CBTC system.At the same time,the DFTA platform based on MFC is developed to calculate the reliability index to increase computational efficiency,which is based on the theoretical analysis.The results have great significance to improve the CBTC system design and reduce the maintenance cost in the further.In order to evaluate the reliability of CBTC system objectively and correctly,cloud model and combination weighting method are combined to evaluate the reliability of the CBTC system in this thesis.Firstly,according to the function and structure of the CBTC system,the comprehensive functional evaluation model of the CBTC system is established.The combination weighting method combines with the subjective weight by the analytic hierarchy process(AHP)and the objective weight by the CRITIC method.Secondly,according to the fuzzy failure rate of the basic unit in the model,the cloud representation is obtained according to the cloud operation rule.Finally,the virtual cloud of the CBTC system reliability synthesis index and the reliability evaluation cloud are compared to obtain that the CBTC system can complete the prescribed functions.The result shows that the reliability evaluation method of CBTC system based on cloud model and combination weighting method can correctly and objectively describe its ability to complete the prescribed functions and provide reference for the evaluation of CBTC system.