Integrating STPA Extended for Coordination into SysML Using RAAML

Abstract

As Model‐Based Systems Engineering (MBSE) becomes prevalent in engineering practice, the Department of Defense (DoD) requires a consistent methodology to conduct and record system safety analyses in the system model. Systems Theoretic Process Analysis (STPA) is a relatively new safety and hazard analysis method that utilizes the principles of Systems Theory and abstraction to analyze today's complex systems. Systems Theoretic Process Analysis Extended for Coordination (STPA‐Coord) provides a framework to design safe coordination among a system‐of‐systems architecture, which is needed for next‐generation integrated military systems. This research presents results from conducting an STPA‐Coord in Systems Modeling Language (SysML) using Risk Analysis and Assessment Modeling Language (RAAML), a recent extension to SysML that provides tools and guidance for multiple safety analyses. Results describe deviations from the RAAML standard and suggest modifications to RAAML for STPA‐Coord. Results include qualitative and quantitative observations conducting an STPA‐Coord using SysML, including time required for the effort and observed benefit over document‐based methodologies.