基于STPA方法的平交道口安全需求分析
A safety requirements analysis approach for level crossing based on STPA

摘要 现代平交道口控制系统多为由计算机组成的基于通信的控制系统，该类型系统中的危险致因大多源于系统组件间的复杂交互场景未得到充分辨识和控制。为了避免平交道口事故的发生，提出一套基于系统理论过程分析（STPA）的铁路信号系统安全分析方法。借助对传统STPA方法的改进及XSTAMPP软件，以平交道口控制系统为案例进行了安全分析。研究结果实现了安全需求可根据危险分析结果自动生成，解决了传统STPA过程过于依赖人工的问题；分析得到的平交道口控制系统安全需求被自动转化为线性时序逻辑（LTL）语言描述的形式化规范，避免了传统STPA分析结果用自然语言描述可能存在的歧义性，为基于模型的系统设计、测试和验证提供参考。
Abstract：Modern level crossing control systems are mostly computer-based and communication-based control systems. The causal factors in this type of system are mostly due to the fact that the complex interaction scenarios between system components have not been fully identified and controlled. In order to avoid the occurrence of level crossing accidents, this paper proposes a set of safety analysis methods for railway signal systems based on System Theory Process Analysis (STPA). With the improvement of the traditional STPA and the XSTAMPP, this paper takes the level crossing control system as a case for safety analysis. The results achieve the automatic generation of safety requirements based on the hazards analysis results and solved the problem that the traditional STPA process is too dependent on labor. Meanwhile, the safety requirements of the level crossing control system are automatically converted into a formal specification of the Linear Temporal Logic (LTL) language description, which avoids the possible ambiguity in the natural language description of the traditional STPA analysis results. It provides references for a model-based system design, testing and verification.