Research On Train Communication Cooperation Under V2V Communication Environment Based On State Machine

Although traditional CBTC system have realized the moving block which support high-density running,the large quantity of ground device and complex interface lead to high construction cost and later maintenance effort.On the basis of traditional CBTC system,the next generation of train control system based on vehicle-to-vehicle communication integrates part of function of ground device into on-board equipment.What's more,it builds up direct communication among trains.In this way,it can cut down the number of ground device and interface and increase communication real-time quality in some degree.Despite the advantages brought by vehicle-to-vehicle communication based train control system,there are also some problems.As the original train operation mode in which all the trains are controlled by ground equipment changed into the way in which all the trains are controlled by themselves,the train cannot directly get the information about front train that could be used to track.Considering that trains can communicate with each other,the train could complete the front train identification and establish communication with its front train through reasonable communication cooperation strategy.Finally,train following operation can be achieved.In vehicle-to-vehicle communication environment,the trace relationship between adjacent trains can be jointly managed by adjacent trains.As train is a moving object,the adjacent relationship between trains will change with the change of train position.The adjacent relationship can affect the tracking relationship,which can be solved by the communication cooperation between adjacent trains.Thus,the communication cooperation mechanism includes the process of front train identification and managing trace relationship between adjacent trains.In this paper,the research on communication cooperation among trains is focused on application level.In view of the above problems,the paper concludes the characteristic of communication among trains through exploring the communication structure of train.After that,the paper comparatively analyses the frequently used modeling method in train control system and chooses state machine theory to model the communication cooperation strategy among trains.And then the paper described the general model flow of state machine in tool named by Stateflow.Next,we researches the communication cooperation strategy among trains on on-board equipment level,the main content include:(1)Designing the three layer logistic architecture of control module of train communication cooperation in on-board device.And divides it into information send and receive module,core function handle module,database module and display module according to functions.(2)Proposing a method that can rely on the train itself to identify its front train.Via successive analysis the communication objects of train which include control centre ITS,train data manage unit named by TMC,ground OC,communication device AP and communication trains on line,we prove the possibility of realizing the front train identification by train.Through analyzing the information sources of communication object for one train,we conclude that one train can communication with other trains on line and filter the front train and there is no need to add any devices.(3)By researching the communication requirements between adjacent trains and analyzing the influence factor to trace relationship,the paper designs programmers that trace relationship can be managed by two adjacent trains.(4)Building the state machine in the light of train communication cooperation strategy and then analyzing the simulation result,we come to the feasibility.In order to further verifying the feasibility of train communication cooperation strategy,we build the minimum system testing environment of logic function in on-board software by using existing resources in laboratory.And then test the function of front train identification and trace relationship management.At last,we draw the conclusion of whole paper and prospect the next steps aimed at research directions.