Research On Fault Propagation Characteristics Of Vehicle On-board Controller System Of FAO Based On Complex Network

With the rapid development of the social economy,the urbanization process has gradually accelerated,the number of urban population has increased dramatically,and the urban rail transit has become the main mode of travel for people.The signalling system,as the key equipment to ensure the operation safety and improve transportation efficiency of the urban rail transit system,once the failure occurs,due to the cross-coupling within the system,it will cause the initial failure to spread in the system,which at least may cause operational delay and passenger detention,and even more may cause a large number of casualties and huge property losses.It will also have a significant impact on the normal social traffic order.Therefore,studying the fault propagation mechanism in the system and mining the fault propagation rules can provide reliable basis for early warning and prevention of fault in future line operation,thereby improving the operational reliability and safety of rail transit system.Based on the complex network theory,this paper proposes a modeling method for fault propagation of vehicle on-board controller(VOBC)system,and analyzes multiple statistical characteristics of the model to identify the critical failure events in the process of fault propagation.In addition,based on the proposed fault propagation model and combined with load-capacity model of cascading failure,a fault propagation path search algorithm is designed.By changing the parameter values of the model,the maximum possible fault propagation paths under different conditions are obtained and compared,providing reliable basis for early warning and prevention of fault in future line operation.Taking Yanfang Line as an example,this paper illustrates the specific implementation process of the above modeling method and fault propagation analysis method.The main work and achievements are as follows:(1)Aiming at the problem of fault propagation modeling of VOBC system,this paper combines the system composition structure and function realization principle of VOBC to analyze the commonly used complex network modeling method based on system components,revealing the limitations of this modeling method.Furthermore,a fault propagation modeling method of VOBC based on failure events is proposed,and the hidden fault information is mined from the existing operational fault data to construct a fault propagation model of VOBC system,which provides a good model foundation for the subsequent analysis of fault propagation characteristics of the system.(2)Aiming at the identification of critical failure events in VOBC system,this paper selects global parameters such as the degree and degree distribution of the node,clustering coefficient,diameter and average shortest path length,betweenness of the network,etc.to comprehensively analyze the scale-free characteristics,the clustering characteristics,the closeness of the proposed fault propagation model,and identifies the critical failure events in VOBC system,which provides theoretical guidance for preventing the occurrence of critical failure events and thereby reducing the failure occurrence rate.Taking Yanfang line as an example,the modeling and analysis method of this part is verified,and the results show that the analysis method can achieve accurate identification of critical failure events.(3)Aiming at the problem of quantitative analysis of the fault propagation path of VOBC system,based on the constructed fault propagation model of VOBC,combined with load-capacity model of cascading failure,a fault propagation path search method is designed.By changing the parameter values in the model,the maximum possible fault propagation paths under different initial danger degree and danger degree are compared and analyzed,which can provide reliable basis for early warning and prevention of fault under the condition of cost control.Finally,on the basis of the above-mentioned Yanfang line fault propagation model,the proposed fault propagation path analysis method is verified and compared with other representative analysis method.The results show that the proposed method has advantages in reflecting component fault types,component failure modes and description details and identification of critical failure events.28 figures,11 tables and 59 references.