基于在线一致性测试理论的CBTC车载ATO功能测试研究

Research on Verificaition of CBTC Onboard ATO Functions Based on Online Conformance Testing Theory

自动列车驾驶系统(ATO)是CBTC系统的重要组成部分,验证测试其控制功能逻辑的正确性和安全性至关重要。介绍了ATO控制原理和功能,分析了CBTC中典型的两车追踪控制运行场景控制流程,得到了该场景下的列车运行安全需求。结合时间自动机理论,建立了包含列车动力学、车载ATO、ZC以及时钟控制器的两车追踪场景时间自动机网络模型,验证了模型中安全需求的正确性;基于一致性测试理论,定义了被测车载ATO软件与测试环境的可观测输入/输出接口,利用UPPAAL-TRON工具设计了被测车载ATO软件的一致性测试框架,并进行了一致性测试分析。在此基础上,采用变异测试,针对典型的车载ATO软件功能实现错误(错误的安全距离、静态限速、功能逻辑以及命令丢失等)进行了安全性验证。结论表明:该在线一致性测试方法能够及时发现车载ATO软件行为与规范模型的不一致,有效提升了车载ATO功能测试的检错能力。

The Automatic Train Operation(ATO)system is an important part in the CBTC(Communication Based Train Control)system.It is of significant importance to verify and test the correctness and safety of the logic of its control functions.In this paper,the control principles and functions of the ATO were introduced and the safety requirements were generated by analyzing the control flows of the typical operational scenario of one train tracking another in a CBTC system.Based on the theory of timed automata,the model of timed automata network consisting of the train,on-board ATO,ZC and timer in this scenario was built,where the correctness of the safety requirements was verified.Based on the theory of conformance relation,the observable input/output interfaces between the on-board ATO under test and the testing environment were defined.A testing framework for the on-board ATO was designed using UPPAAL-TRON,based on which the conformance testing was carried out.Moreover,the safety of the control logic functions was also verified by conducting the mutation testing to inject typical faults into the real on-board ATO software,such as the wrong safety distance,wrong static speed constraint,wrong functional logic,the loss of command.The experimental results show that the online conformance testing method can detect the inconsistency between the real ATO software and its specification model,which can effectively improve the error detection capability of the functional testing on on-board ATO.