Functional Modeling And Verification Of Urban Rail Transit Train Control System Based On Train-to-Train Communication

With the development of communication technology,in order to improve the communication based train control system(CBTC),the train control system based on train-to-train communication has become the main development direction of the next-generation urban rail transit train control system.The train control system based on train-to-train communication is based on the CBTC train control system,and transfers some of the ground equipment functions to the onboard equipment,which can optimize system structure and realize the onboard control concept.As a new train control system,formal modeling verification and simulation testing are essential before it is put into use,which can detect possible design defects in the system in advance and ensure that the system meets the requirements of safety,functionality and performance.It is of great significance to the research and application of the system.This thesis takes the train control system of train-to-train communication as the research object,the main work is as follows:(1)By analyzing the structure and characteristics of the new train control system,and focuses on selecting the new functions in the new train control system and the modules whose function distribution has changed,mainly including route selection in the train station,Three functional modules are generated for the identification of the preceding train and the mobile authorization.The specific implementation process of each function and the information exchange between each device are analyzed.The backup mode describes the process of the train switching to the backup mode in the event of a train-to-train communication failure.(2)By comparing and analyzing the characteristics and pros and cons of various formal modeling methods,the colored Petri net theory is selected,and according to the idea of "top-down" hierarchical modeling,the hierarchical timed colored Petri net model of each function is established.The function verification and state space property analysis of the model are completed by using CPN Tools.The state space report of the model verifies that the model can meet the requirements of accessibility,boundedness,liveness and fairness,and the train is obtained through simulation analysis.The success rate of backup mode switching under fault conditions is analyzed,and the trains that can successfully switch modes are analyzed,and the time required for the backup mode switching of trains and the running time distribution diagram after successful switching are obtained.(3)On the basis of formal modeling,a simulation platform based on the train control system of train-to-train communication is developed under the environment of VS2013.Through the demand analysis and structural design of the simulation software,the development of a new type of train control system simulation software is completed.Corresponding test cases are designed to simulate the running state of the train under the most realistic conditions possible by inputting specific line parameters,train data,fault conditions and other information,which further demonstrates the feasibility of the designed train control system scheme.The results show that the established functional model can effectively meet the functional requirements and safety requirements of the train control system of train-to-train communication,and can provide a certain reference for the modeling and analysis of the train control system of train-to-train communication.