Topology-based Safety Analysis for Safety Critical CPS

Since Cyber-Physical Systems (CPS) may exhibit different structures and emergent behaviours during different operational phases, while also being safety critical, it is useful to perform systematic safety analyses tightly relying on the functional and components topologies of such systems. Our proposal is to perform FMEA and FTA analyses as soon as possible in the CPS design process in order to identify and mitigate the risks related to some safety critical structures and behaviours. Thus, these preliminary analyses enable to propose relevant design modifications and improvements such as optional or additional redundancies, components repairability capabilities or relevant control strategies, taking into account the complexity and the potential variability of the structure and the behaviour of the systems. This work derives from previous MBSE (Model-Based System Engineering) and MBSA (Model Based Safety Analysis) integration studies, performed during the early phases of the design of safety critical mechatronic systems, including interconnection components and multi-physical interactions. It relies mainly on M2M (Model to Model) and M2T (Model to Text) transformations and appropriate SysML metamodeling. The proposed CPS safety analysis methodology is illustrated using an aeronautic industrial case study.