A Safety-critical Computer Platform Software Design For Urban Rail Transit Signaling System

With rapid development of urbanization in China, come the population of city increasing and an urgent need for more urban rail transit. Safety-critical computer systems are key requirements of communications-based train control (CBTC) systems. The software design of safety-critical computer systems is a part of CBTC systems, in which operating systems’ configuration and platform software development are key requirement.The application background of this paper is urban rail transit. For the requirement of reliability, availability, maintainability and safety of safety-critical computer systems, this paper abstracts the hierarchy of safety-critical computer and briefly describes the characteristics of safety-critical hardware architecture, real-time operating system and safety-critical platform software.On this basis, the paper takes a depth analysis and exploration of the principles and methods of VxWorks embedded real-time operating system. VxWorks is a real-time operating system with high-performance and high-reliability that suitable for the safety-critical computer platforms. But VxWorks is hard for porting and driver development. The paper summarizes a standard process of VxWorks system porting and driver development.The paper describes a safety-critical computer platform software design based on the VxWorks operating system for urban rail transit signaling system. The paper analysis the critical data types of urban rail transit applications and designs a platform software with a set of key technologies, such as time synchronization, data synchronization and vote, active/standby fast-switching and safe communication protocol.Finally, the paper takes simulation of this safety-critical computer system. The simulation results show that this design can meet the performance and safety needs of urban rail transit signaling system.