Towards Continuous Assurance Case Creation for ADS with the Evidential Tool Bus

TL;DR

The paper addresses the challenge of maintaining safety assurance cases for autonomous driving systems in the face of changing requirements and learning-enabled components. It introduces the Evidential Tool Bus (ETB) as a framework to automate evidence generation, argument instantiation, and continuous maintenance via Datalog-based workflows. Using an industrial Automated Valet Parking (AVP) case study, it demonstrates pattern creation, formalization, tool integration, distributed deployment, and incremental maintenance of assurance cases. Findings indicate that ETB enables scalable, distributed, and repeatable assurance processes, reducing maintenance effort and supporting continuous assurance for ADS, with future work to extend automated workflow generation from patterns and to incorporate confidence arguments.

Abstract

An assurance case has become an integral component for the certification of safety-critical systems. While manually defining assurance case patterns can be not avoided, system-specific instantiations of assurance case patterns are both costly and time-consuming. It becomes especially complex to maintain an assurance case for a system when the requirements of the System-Under-Assurance change, or an assurance claim becomes invalid due to, e.g., degradation of a systems component, as common when deploying learning-enabled components. In this paper, we report on our preliminary experience leveraging the tool integration framework Evidential Tool Bus (ETB) for the construction and continuous maintenance of an assurance case from a predefined assurance case pattern. Specifically, we demonstrate the assurance process on an industrial Automated Valet Parking system from the automotive domain. We present the formalization of the provided assurance case pattern in the ETB processable logical specification language of workflows. Our findings show that ETB is able to create and maintain evidence required for the construction of an assurance case.

Figures (7)

• Figure 1: Overview of the architecture of the automated valet parking system.
• Figure 2: Top-level of GSN-based pattern for safety case construction for AVP system.
• Figure 3: Datalog formalization of the complete assurance pattern.
• Figure 4: Implementation of a wrapper for the integration of OpenSBT into ETB.
• Figure 5: a) shows an excerpt of the claim database of ETB in JSON format and b) shows an overview of corresponding claims in GSN-based format.