Research On Automation Technology Of Hazard Analysis And Safety Requirement Capture In STPA

Compared with traditional safety analysis methods,System Theory Process Analysis(STPA)has a stronger hazard identification capability for the safety analysis of complex component interaction systems.STPA has been successfully applied in various fields so far,but the STPA method has shortcomings such as insufficient automation,many artificial factors and low analysis efficiency.This paper forms a more rigorous approach for safety analysis by formalizing some of the processes in STPA.The purpose is to make the whole analysis method clear,easy to understand and use,so that ordinary engineering and technical personnel can also quickly grasp,thus contributing to the promotion and application of safety analysis work.The specific work of this thesis is as follows:Firstly,an STPA control structure model combining control structure diagram and four-variable model is proposed.By modeling a typical control loop and strictly defining the basic concepts in the model,the entire analysis process is more rigorous and standardized.Based on the STPA control structure model,the SCR method is used to extract the control structure model variables,so that the variable extraction does not need to rely entirely on the analyst's brain storm,which improves the efficiency and accuracy of the analysis.Furthermore,using the tool to verify the extracted system behavior rules can ensure the consistency and completeness of the system behavior rules,and provide guarantee for the subsequent analysis work.Secondly,in order to simplify the analysis process and improve the efficiency of analysis,this thesis proposes an algorithm to automatically generate unsafe control actions.After constructing the control structure model and extracting the variables and system behavior rules in the model,the po-tential unsafe control behavior is automatically generated,which improves the efficiency and reduces the redundancy.In view of the defects of the key steps in the current STPA analysis to find out the cause of unsafe control actions,this thesis proposes an algorithm that assists in generating accident scenarios,which can directly generate accident scenarios for each unsafe control action,significantly improving the efficiency of analysis..Finally,a typical case study is conducted.Taking the hazard analysis of the aircraft automatic throttle control system as an example,the STPA control structure model is constructed and the detailed analysis process and results are given using the improved hazard analysis method.The case study shows the effectiveness of this method.In addition,by demonstrating the tools that automatically generate unsafe control actions,it can be explained that the automation technology proposed in this thesis can be used in engineering practice and is conducive to the promotion and use of the entire safety theory and method.