Model-based generation of safety test-cases for Onboard systems

Abstract

As a core subsystem in CTCS-3, the Onboard subsystem is a typical safety-critical system, in which any fault can lead to huge human injury or wealth losing. It is important to guarantee the safety of train control system. Safety testing is an effective method to detect the safety holes and bugs in the system. However, because of the special characters of train control system like diversification, structural complexity and multiplicity of interfaces, most safety testing for train control system are manually executed based on specialistic experience, which leads to a huge testing workload. Besides, manual generation will easily cause the problem of missing test cases. In this paper, a model-based safety test method is introduced. We select a core function of onboard system as the representative to study the method. This function was analyzed by Fault Tree Analysis (FTA) to get the bottom events, which are used to turn to fault models being injected into the whole system model, affected system safety, and a set of timed automata network model of the core function is built using the tools of UPPAAL. Then COVER, the real-time test case generation tool, is used to generate the safety test cases from the system model (included fault models) automatically, and states transition criteria is customized based on preferences to achieve user-defined test, the test accuracy and efficiency is improved.