A Hazard Analysis Method for Software-Controlled Systems Based on System-Theoretic Accident Modeling and Process

Hazard analysis is critical for safety assurance of smart systems which is usually controlled by software. As a novel causality model, Systems-Theoretic Accident Modeling and Processes (STAMP) has been used in various areas to obtain more causal factors during hazard analysis. However, the application of STAMP thus far is ad-hoc with no rigorous procedure to analyze the system hazards effectively, and the quality of the analysis results can't be guaranteed. Furthermore, the temporal factor as an important cause of hazards has been paid little attention in STAMP based analysis. With the purpose of overcoming these limitations, this paper presents a systematic method for hazard analysis based on STAMP. And the Hazardous Control Action Tree (HCAT) is proposed to model and analyze all the situations should be considered for hazard analysis. Also, several rules are given to guide the hazard analysis of temporal conditions in the control processes. Finally, a case study is used to illustrate the feasibility and availability of proposed method.