Research On Hot Standby Switching Mechanism Of Double Three-Vote-Two Safety Computers

The security computer is the core equipment of the train control system.At present,the security computer widely adopts two redundant structures of two-by-two and three-by-two.With the rapid development of computer,communication and information processing technology,in order to further improve the reliability and ensure the safe operation of the train control system,the safety computer with two-by-three and two-by-two redundancy structure has been put into practical application.In this paper,the switching mechanism of a two-machine hot-standby safety computer system is studied.Based on the analysis of the structure and working principle of the system,the synchronization mechanism,fault detection and switching evaluation,and switching mechanism in the process of hot standby switching are studied,and the reliability and safety of the system are analyzed.The simulation software of two-by-three-to-two-twin hot-standby switching mechanism is constructed to verify its feasibility,reliability and safety.The main research work of this paper is as follows:First,the synchronization mechanism of two-by-three-out two-pair switching is studied.Based on the analysis of the system structure,working principle and the synchronization mechanism of the existing railway signal system,the intra-system and inter-system synchronization mechanism of the two-by-three(two-by-three)-two-by-two redundant system is studied in depth according to the structural characteristics of the two-by-three-two system to avoid common mode fault.Secondly,the fault detection and evaluation mechanism of two-way three-way two-pair hot standby switching is studied.By analyzing the system state and switching state of the two-by-three(two-by-three)subsystem,the fault detection within and between the systems is carried out,and the system switching is evaluated by combining the fault detection results with the system state in which the system is located.Thirdly,the switching mechanism of two-by-three-to-two is studied.Firstly,the transformation process of each system state is analyzed when the system is switched between master and backup.Secondly,according to the results of fault detection and switching evaluation,the switching mechanism of two-by-three is obtained.Finally,the markov model is used to analyze the reliability and security of the three-by-two and two-by-three two-by-two systems,and the reliability and security curves of the system are obtained by MATLAB.The results show that the two-by-three three-by-two redundant system based on the switching mechanism has high reliability and considerable security.Fourthly,Stateflow model is used to simulate the switch mechanism,and the correctness of the switch mechanism is verified by test cases.Based on the research results of three key problems in the process of switching,the simulation software of two-by-three switching is designed to realize intra-system and inter-system synchronization mechanism,and the system switching evaluation and switching process are realized by simulating fault detection.The research shows that the hot standby switching mechanism of the two-by-three-out two-double machine can achieve accurate switching and ensure the reliability and safety of the system.