Research On The Application Of COTS Components In Train Control System Safety Computer

With the development of computer software and hardware technology in recent years,the train control system of railway transportation has realized the continuous exploration and innovation in technology,which provides a solid foundation for the high-speed railway and urban railway transportation.The train control system ensures high efficiency,high safety and high reliability.Meanwhile,it should also provide a good compatibility for the multiple subsystems.As the arithmetic unit to realize the data processing function,the safety computer becomes the key part of the next generation train control system.For its well properties of reducing cost,improving flexibility and shortening development cycle,COTS hardware has replaced specific components designed for the traditional system gradually,and is applied to the design of safety computers.Due to the "black box" feature of COTS components,it may bring some influence to the safety of the system.It is of great importance for the construction of safety computers in train control system to solve the safety problem of the safety computer system applying COTS components.Therefore,based on the research of the hazards and safety mechanism,a method of safety verification is proposed,and safety tests and verification are carried out in this paper.On the basis of the research on the application of COTS components and safety computers at home and abroad,the structure features and functional demands of the safety computer in the next generation train control system are analyzed,and the influence of COTS components on the performance of safety computers is expounded.Then the thinking of hazard analysis based on the system model is proposed,the model is established,and the HAZOP method is used to analyze the hazard source of the system.Finally,a list of hazard source analysis is established.With the combination of the safe operation mechanism of safety computers and the trusted computing technology in the field of information security,the feasibility of the application of trusted computing in safety analysis is illustrated.A method for safety verification is proposed to detect the risk of the system and verify the safety of the system,and an embedded safety code module(ESCM)in the safety computer management unit(SCMU)is established in this paper.The composition of the safety base,the calculation of safety verification,the construction of the safety chain,and the process of safety verification of the system are described in detail.Then the correctness of the proposed method is proved by mathematical logic.Based on the existing safety computer,a safety verification test platform is establish.With the application of software fault injection technology,test cases based on the FARM model are established,and the functional module of fault injection is designed,and the fault injection test system is constructed.The test results show that the safety verification method proposed can be effectively applied to the safety analysis of safety computers,and the system containing COTS components can satisfy the safety requirements.