Application Research On Computer Interlocking System Based On FlexRay Bus

Railway computer interlocking system, as a safety-critical system, plays a vital role inthe achievement of safe and fast operation. Computer interlocking system goes through threestages of development: mechanical interlock control,6502electrical interlocking control,computer interlocking control, All-electronic computer interlocking control. All-electroniccomputer interlocking system combins of experience of decades in the development ofcomputer technology and the results of modern electronic interlocking system, with featuresof high reliability, high security and intelligence. In the current All-electronic computerinterlocking system uses RS485bus or CAN bus, etc for achieve information transmissionbetween executives layer and interlock logic layer. FlexRay bus is vehicle networkcommunication protocol designated by BMW, Daimler Chrysler, Philips, Freescale, Boschand other companies of the FlexRay Consortium in2000, Its appearance meets thecommunications needs of vehicle control and improves maneuverability, reliability andcomfort.This paper described the research status of FlexRay bus and computer interlockingsystem, and analyzes the main characteristics of FlexRay bus, which contains physicaltransmission bus communication mechanism, frame structure, starting with the wake-nodecluster, clock synchronization, and topology. Compared with traditional CAN bus, FlexRaybus has a huge advantage with high communication speed, real-time and good large effectivedata capacity. It supports multiple topologies,which can be flexibly adjusted according toactual situation. After analyzing the overall architecture of the computer interlocking system,All-electronic computer interlocking redundant bus topology based on FlexRay bus wasproposed. Bus node interface hardware circuit design was given based on microcontrollerAtmega128L, the bus controller MFR4200and bus driver TJA1080. And the correspondingnode initial configuration, node communication processes, data receiving ‘node running statusand node wake-flow are also given. Meanwhile,a mathematical model based on the FlexRaybus communication circuit reliability is constructed, and then the mathematical calculationsabout the reliability is taken on. Besides, FlexRay bus communication security analysis wasgiven. Because communication network in computer interlock system must have fail-safefeatures, this paper studied fail-safe of FlexRay bus communication network. As to systemsurvivability, redundant FlexRay bus topology underlies the principle of fail-safe. Meanwhile,various effective measures are taken to ensure the integrity, time and testability ofinformation transmission in the physical layer, data link layer and application layer of theFlexRay bus. Finally, the paper summarized the research and pointed out some of theproblems that existed in the research.