Reliability Evaluation Method For Train-ground Communication System Considering Epistemic Uncertainty

Urban rail transit has changed people's way of life and the way of traveling,the train-ground communication system is one of the key subsystems,and its reliability directly affects the safety and stability of the rail transit.In recent years,new technology and equipment widely used in train-ground communication system,on one hand,greatly improve the system function,while the complex structure of the system,leads to the relationship between the mutual coupling equipment perplexing;On the other hand,the equipment of the train-ground communication system is still in the early stage of the life cycle,and we cannot obtain sufficient fault data,which leads to the new challenge to the reliability evaluation of the train-ground communication system.In this paper,the reliability analysis method of train-ground communication system with epistemic uncertainty is proposed.Firstly,the methods of dealing with epistemic uncertainty problems are summarized.Secondly,the method of system reliability evaluation based on fault tree analysis is described in detail,and the method of qualitative analysis and quantitative analysis of fault tree is expounded.Then,the dynamic fault tree model of train-ground communication system is established by using failure mode and effect analysis.And the fuzzy failure rates of the basic events are obtained based on the domain experts.At last,the method of mapping a dynamic fault tree into an evidence network is present,especially for a AND,OR gate and FDEP gate in detail.The fault probability and importance index of train-ground communication system are obtained,which can provide decision support for the reliability improvement and maintenance of train-ground communication system.The main contents of this paper are as follows:1.Methods to deal with epistemic uncertainty problems are summarized.This paper focuses on the use of fuzzy sets,evidence theory,probability theory,interval analysis based on non-probability analysis method to deal with it.2.Reliability evaluation method of complex system based on fault tree analysis is discussed.This paper mainly analyzes the construction of the fault tree model,the qualitative analysis method,the quantitative analysis method and the fuzzy fault tree analysis method.The fault tree model of train-ground communication system isestablished,And the fuzzy failure rates of the basic events are obtained based on the domain experts.3.The system reliability evaluation method based on dynamic fault tree and evidence network is studied.The method of mapping a fault tree model(FT)into an evidence network(EN)is discussed.Taking train-ground communication system as an example,we obtain the failure probability of the train-ground communication system and importance index data,which can provide decision support for system fault diagnosis.Experiments show that the method is simple,feasible and effective.