Research Of The Test Methodology Of CTCS-3 Based On STAMP

The Chinese Train Control System(CTCS)is the core technique and key equipment of Chinese high-speed railway which operates over 300 kilometers per hour.CTCS-3 has been greatly improved and became a mature standard with computer managed safety,interactive complexity and decoupling difficulty.Based on the characteristics of CTCS-3,performing safety verification on system level during safety test has become one of the challenges.The primary task and contribution of this paper are as follows:A System-Theory Process Analysis-Test Case Genaration Method(STPA-TCG)is given based on the high complexity,safety concern and emergent properties of CTCS-3 along with test concerned optimization and refinement of Systems-Theoretic Accident Modeling and Processes(STAMP)model based safety analysis.Moreover,the problem that traditional safety test is still function-oriented rather than safety-oriented is solved by combining safety analysis method and test method hence improving the directivity of safety test.In regular CTCS-3 safety test generation process,it is challenging to differentiate non-safety-related test cases and it is also affected by experience restoring.Using the STPA-TCG method,we can firstly identify the system-related accidents and hazards,apply the control process and safety constraint to identify unsafe control behavior of the system,thus analyze the cause of unsafe control behavior and directly transform the casue scenario of the hazard into test cases.This will improve the quality of test cases by avoiding design test cases for sepcific device or function.Thus the test cases could be traced back to system level hazards and accidents,which reduce the number of safety-related test cases and improve the efficiency.In this paper,the typical example of CTCS-3 control system is used to generate test cases by STPA-TCG method.The feasibility of the method is verified,and concrete details of the practical application are given.Comparing the test cases obtained in this paper with traditional test cases shows that safety test cases will achieve higher directivity using STPA-TCG method,which is an important supplement to the test case library.