Research On Fault Injection Method Of Chinese Train Control System Based On Combinatorial Test

With the rapid development of high-speed railway in China,train speed has been constantly increasing.As the technical equipment for monitoring,controlling and adjusting train speed,the safety of Chinese Train Control System(CTCS)is particularly vital.However,the complexity and particularity of railway fields make the safety verification of CTCS much harder.The simulation platform of train control system can simulate the whole process of train operation in real environment,which can realize the safety-related test.The technology of fault injection for simulation platform is used to collect the reliability information of system,which can evaluate the design level of system safety protection,simulate the field fault,inject the effective fault into the system to be tested,analyze the system response and evaluate the effectiveness of system redundancy mechanism.Traditional fault injection technologies of CTCS are used to adopting single fault injection,which is easy to be filtered,and hard to verify the effectiveness of its redundancy mechanism.In this thesis,a fault combination injection method of CTCS based on combinatorial test is proposed,which can verify the effectiveness of redundancy mechanism by multiple fault combination injection.Firstly,taking the fault degradation scenario of CTCS for example,the fault injection combination test case table B is generated by the test case generation algorithm.Secondly,by using the method of fault combination injection,the test cases are injected into the system(CTCS or simulation platform of CTCS)to be tested to generate the test results with certain rules and the order of tester.Thirdly,according to the combinatorial test case table of fault injection,test results and additional test cases,the frequency of inducement elements are calculated by iterative positioning method of inducement combination and support degree support(x?y).The inducement elements are arranged in descending order of frequency degree to get an orderly list of fault inducement elements.Finally,from the following relationship of inducement elements,the frequent term relationship matrix of fault injection combinatorial test is constructed,the suspicious degree ? of fault inducement combination is calculated,and the ranking table of minimal failure-causing suspicious degree of fault inducement combination is generated to realize fault positioning.Based on the simulation platform of CTCS of high-speed railway from Beijing to Shenyang in "National experimental teaching center of virtual simulation of information and control for rail transit" at Lanzhou Jiaotong University,the proposed method can effectively test the redundancy mechanism of CTCS with the field data and actual information of equipment,and locate the minimum combination of fault caused by multiple fault coupling,which can provide the reference for the follow-up work of fault diagnosis,and reduce the diagnosis time and cost.