Details

Autor(en) / Beteiligte

• Umeda, Hiroki
• Namihira, Kohsuke
• Okubo, Naoko
• Ueda, Yasushi
• Morisaki, Shuji
• Katahira, Masafumi

Titel

FMEA Focusing on the Interaction Between Physical and Computational Elements in Cyber-Physical Systems

Ist Teil von

• 2021 Annual Reliability and Maintainability Symposium (RAMS), 2021, p.1-7

Ort / Verlag

IEEE

Erscheinungsjahr

2021

Quelle

IEEE/IET Electronic Library (IEL)

Beschreibungen/Notizen

• This paper proposes an extended Failure Mode and Effect Analysis (FMEA) method to capture the interaction between physical and computational elements. Autonomous control of Cyber-Physical Systems (CPS), such as launch vehicle and spacecraft, has the interaction of physical and computational elements. Therefore, it is important to analyze failure scenarios caused by the interaction between physical and computational elements. When analysts accurately capture and analyze dynamic behaviors such as state changes and interaction during and after a failure as a failure scenario, the failure scenario promotes an accurate understanding of system failure and effects, helps appropriate design improvements. However, it is not easy to analyze CPS's failure scenarios involving many factors using conventional FMEA, which is because FMEA focuses on each element. The proposed method sequentially identifies failure modes and failure scenarios for combinations of elements using three models. The first model is the input-output Structural Model (SM), which identifies specifications that have interaction between physical and computational elements. The second model is Tree Model extended from Goal Structuring Notation (GSN), which supports analysis in guiding combinations of conditions from the perspective of a system's hierarchy. The third is a sequence model that shows failure scenarios, and Event Sequence Diagram (ESD) visualizes the state transitions of elements, including the passage of time. As a result of applying the proposed method to four CPS spacecraft systems, the number of failure modes, including the interaction between physical and computational elements, increased 2 to 8 times that when using conventional FMEA worksheets and guidewords about Hazard and Operability Study (HAZOP).