The Research Of Train Positioning Xystem Security Based On Fault Tree And Petri Net

The train positioning subsystem is the important part of the entire column of the train operation control system.It keeps providing real-time location of the train and the train track occupancy information to guarantee the train efficient and safe operation control. The train location information provides a basis for safe driving interval, its positioning accuracy and security plays a vital role to determine the safey protection distance of the train. The train positioning methods and the technology used is an important factor to determine the train operation control system standard.While the train control system security is a very important issue, especially with the rapid development of high-speed railway, its safety does not allow to ignore. The railway signal system security assessment research in the developed countries is already very mature, China gradually attaches importance to the study of safety assessment, and has formed a complete set of safety assessment theory and method. This article takes the train positioning system as the object, combining the fault tree analysis of static and dynamic model Petri method, studies on its safety.This paper, based on failure mode effects and criticality analysis (FMECA), has analysed the function of positioning system, including qualitative and quantitative analysis, got the dangers matrix, found a number of potential failure modes, and its causes, local impact on the upper and the whole system, as well as the severity of the consequences of the various failure modes, failure frequency, probability and criticality of the system impact. On this basis, establishes the fault tree model, through the quantitative analysis of the critical failure mode to determine the positioning of the level of security. Then based on the theory of Petri net, establishes the model of the positioning hardware and transmission, determines its security level with quantitative analysis. Finally, based on the Petri net model, simulats failover, using the Visual C++programming, prepared on Windows XP Chinese platform software simulation interface. The software is composed of two functional modules, simulation and calculation, using the interactive interface to manage the information through the control menus and icons to achieve the function of the system operation, graphical and digital display or calculation results.