Formal Model-Based Assurance Cases in Isabelle/SACM: An Autonomous Underwater Vehicle Case Study

Simon David Foster, Yakoub Nemouchi, Colin O'Halloran, Nick Tudor, Karen Stephenson

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Isabelle/SACM is a tool for automated construction of model-based assurance cases with integrated formal methods, based on the Isabelle proof assistant. Assurance cases show how a system is safe to operate, through a human comprehensible argument demonstrating that the requirements are satisfied, using evidence of various provenances. They are usually required for certification of critical systems, often with evidence that originates from formal methods. Automating assurance cases increases rigour, and helps with maintenance and evolution. In this paper we apply Isabelle/SACM to a fragment of the assurance case for an autonomous underwater vehicle demonstrator. We encode the metric unit system (SI) in Isabelle, to allow modelling requirements and state spaces using physical units. We develop a behavioural model in the graphical RoboChart state machine language, embed the artifacts into Isabelle/SACM, and use it to demonstrate satisfaction of the requirements.
Original languageEnglish
Title of host publicationFormaliSE '20
Subtitle of host publicationProceedings of the 8th International Conference on Formal Methods in Software Engineering
ISBN (Print)9781450370714
Publication statusPublished - 7 Oct 2020

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