Research Of CBTC Field Test Sequence Generation Based On Test-trip

In recent years, in order to meet the growing demand for public transport, the development of urban rail transit in China is very rapid. And the communication based train control system (CBTC) has been more and more widely used as a mainstream control system in urban rail lines. Before the operation of urban rail line, field tests should be conducted on-site to verify that the system meets the functional requirements, design specifications, operational requirements, etc. Currently, there are few uniform and accepted field test standards for CBTC system, especially the standardized and systematic field test sequence generation method.The research of test sequence generation for domestic CTCS-3train control system and ETCS (European train control system) is mainly based on the system state to model the system through formal method, and then test sequence is generated. The restrain of formal method is that the system state can be identified and modeled. However, the functional requirement of CBTC system varies frequently, and the difference of implementation for CBTC is also large, hence, the system states of CBTC can hardly be identified and modeled completely. Formal method is more suitable for indoor test where all the system states can be simulated on the simulation and test platform, while for the field test of CBTC whose test environment is complex and part of the system states cannot be identified and reached, it does not suit any more. At present, CBTC field test sequence is still made by artificial way, which is inefficient, full of workload, and would significantly delay the operation of the urban rail lines. Therefore, the research of CBTC field test sequence generation, as a core part of the field test work, is emergent and must be strengthened.Considering the research status of CBTC field test sequence generation, this paper carries out analysis of the CBTC field test (including test line, test cases and test trains), introducing the concept of Test-trip into the CBTC system field test, defining the test sequence that can be executed in the field as Test-trip. Finally, a new CBTC field test sequence generation method based on Test-trip is proposed, whose framework is described as follows.(1) Test section division method:The test line is divided into multiple test sections through the division method based on axle to describe the execution position of each test case more accurately. (2) Execution condition extraction method of test case:The execution process of each test case is analyzed to extract line resources and states of the test train required in the execution process.(3) Feature extraction method of test section:The feature of test line is analyzed to extract feature parameters for each test segment.(4) Method to match test section and the test case:According to the feature of test line and the execution condition of test case, each test case will be assigned to the corresponding test section in support of generating test sequence.(5) Method to create test sequence:Based on the principle of coherent states of test train, test cases are connected to generate several Test-trips, which cover all field test cases.To verify the feasibility of this CBTC field test sequence generation method, an auxiliary generation tool for CBTC field test sequence is designed and implemented. Aiming at target line and target test cases, this tool is used to generate Test-trips. The result shows that our method is feasible and meets the requirements of CBTC field test. Finally, this paper analyzes the deficiency of this test sequence generation method and proposes the task and direction for the next-phase work.