Research On Fault-tolerant And Real-time Optimization For Communication Of Safety Computer In Train Control System

With the application of modern computer and communication technology in the railway signal system,the train operation control system has been gradually transformed from the traditional control technology to the integrated,intelligent and networked direction.As a core hardware equipment of train operation control system,the train control safety computer,which carries most safety functions of train control system,is the key to ensure the safety and reliability of train control system.As the design of the distributed fault-tolerant structure is basically methods on the safety computer,the processing unit relies on communication to realize the coordinated control.So that the fault-tolerant and real-time performance of the communication system directly restricts the safety and reliability of the train control system.Aiming at the communication fault-tolerant and real-time problems of train control safety computer,a communication fault tolerance mechanism and real-time optimization strategy are proposed to improve the safety and reliability of the safety computer in this paper.First,the communication structure and communication requirements of the safety computer were analyzed.It showed that fault tolerance and real-time performance were the important factors that affect the safety and reliability of the safety computer.Meantime,the typical real-time communication technology was summarized and the real-time communication optimization method based on the time triggered architecture theory could meet the real-time and deterministic requirements of the communication system on the safety computer was concluded in this paper.Then from the aspects of fault tolerance and real-time,redundancy fault tolerance technology,group communication fault tolerance algorithm,real-time optimal scheduling model and analysis method based on network calculus were introduced respectively.Thus communication fault-tolerant and real-time optimization theory and design method were established.Secondly,on the basis of the analyzed theory and method,a middleware model of communication fault tolerance and real-time optimization were constructed and their research and design were carried out.The communication middleware mainly included two parts,namely the group communication fault tolerance management and the real-time optimization strategy.According to the fault-tolerant requirements of safety-critical system,the software fault tolerance mechanism based on dual network redundancy and the communication fault tolerance strategy based on group membership protocol were designed to realize the communication fault-tolerant function.At the same time,according to different attribute characteristics of train control safety computer communication data flow,a real-time optimization method based on constrained multi-priority scheduling was proposed,and the characteristics of communication delay were analyzed with the network calculation which proved that this strategy could effectively optimize the real-time communication.Finally,the prototype of communication middleware was set up on the double two vote of 2 of safety computer platform and the experiment was carried out about the fault tolerance mechanism and real-time optimization strategy.According to the results,the communication middleware could effectively reduce the delay of safety critical data and improve the real-time communication through multiple priority scheduling strategies,and the fault-tolerant communication mechanism also achieved failure shielding,recovery and system reorganization and other functions.