Design And Implementation Of Improved Railway Signalling Safety Computer Hardware Structure

ABSTRACT:At present, the development of the Rail Signalling System still adopte traditional signal design principle and concept that based on the principle of superposition, add new control function by adding new different subsystems.It is easy to lead the structure of the signal system more and more complex. Referencing the experience of the development of Avionics System,from independent structure to IMA structure and tending to integration, modularization and platformization.The cumbersome structure of Rail Signalling System can also tend to integrate. As an important equipment to ensure the safety of system in the Rail Signalling System, the Safety Computer should tend to generalization, modularization and platformization,to meet the requirements of simplified Rail Signalling System.As the background of the Rail Signalling System,against the defect of the structure of signaling system,this paper put forward a optimized and simplified Rail Signalling System solution.The optimized Rail Signalling System solution can apply to Trackside Signaling System and Vechile Onboard Signaling System of CTCS-2,CTCS-3and CBTC.Based on the optimized Signalling System,the structure of2xloo2Safety Computer Platform was put forward.The Safety Computer Platform includes Logic Processing Unit (LPU),Peripheral Management Unit (PMU) and Fault Tolerant and Safety Management (FTSM).Analyze the hardware structure of Safety Computer Platform by the relevant safety standards and definition and build Reliability Block Diagram of the platform. Using the method of PDS, calculate and analyze the safety parameter PFH. Analyze the3factors(Diagnostic Coverage、CMooN、FTSM failure rate) that can influence PFH. When the number of Peripherals are determined, the largest influence factor is DC;The influence of more complex redundant structure of FTSM is limited,so,the1oo2is the best choice by meet need of Safety Integrity Level Four (SIL-4); FTSM failure rate should be as low as possible.The paper brought in the diversity-struture design method and concept.Using this design method,design LPU,PMU and FTSM.In the1oo2structure of Safety Computer,one is based on x86computer,the other is based on PowerPC computer.In the1oo2structure of FTSM,one is based on ARM,the other is based on FPGA.To ensure the safety of communication of the Safety Computer Platform,this paper put forward a communication protocol with according with EN50129.1safety standards. Based on the hierarchical diagnosis principle,to ensure the safety of communication in the PMU,take SPAN to monitor I/O data.In the lab, build safety computer test platform with loo2sturture of LPU,loo2struture of PMU and loo2struture of FTSM. After test in this platform,the FTSM can achieve designed function,to manage the safety computer.With the SPAN,the PMU can monitor specific output communication. Verifid the validity of the SPAN.