Research On STAMP-Based Hazard Analysis Method Of IMA System

Integrated Modular Avionics(IMA)has many advantages,but the characteristics of resource sharing and interaction has brought great challenges to the safety analysis.The traditional safety analysis method focus on analyzing critical components to prevent them from failing or providing redundancy to mitigate the effects of failures,it is difficult to identify the hazards caused by component interaction,and these method attempt to prove that the system is safety after the system has been designed,rather than begin the safety analysis at the system requirements level.For complex systems,it is impractical to complete the security analysis after the system has been designed.However,IMA is a complex avionics architecture with many hazards caused by components interaction.The traditional safety analysis methods are no longer applicable.At present,theoretical research on IMA safety analysis is still relatively lack,and there is no effective IMA hazard analysis method.The main work of this paper is to analyze and verify the safety of the IMA system at the system requirement level,and propose a method of modeling and analyzing the safety of the IMA system based on the STAMP model,and use the four-variable model to verifies the results of STAMP model.The specific work of this paper as follows:Firstly,we study the system theoretic accident model,and achieve the goal of safety through the implementation of safety constraints in the design and operation to control the system behavior.we compare the difference between the system accident model and the traditional cause model in the safety analysis of IMA system,and confirm that the safety analysis method based on system theory can identify more hazards of the IMA system.Secondly,we analyze and model the IMA system partition communication module by using the STPA which is based on the system theory model.We construct the hierarchical control structure and use the UML model to describe the process model and control algorithm in the STAMP model.By formally defining the control structure,we accurately describe the unsafe control actions and safety requirements in the STPA method.Finally,we use the four-variable model to model the results of the STPA method analysis at the system requirements level,and describe the relationships among the process model variables using SCR tables.By validating the safety requirements with the SCR method,we ensure the accuracy and reliability of the requirements.In this paper,a safety analysis and verification method based on the system theory model and the four-variable model is proposed.The analysis of the IMA system shows that the system theory and the STPA method have strong applicability in the safety analysis of the IMA system.