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Although the ISO 26262 provides requirements and recommendations for an automotive functional safety lifecycle, practical guidance on how to handle these safety activities and safety artifacts is still lacking. This paper provides an overview of a semi-formal safety engineering approach based on SysML for specifying the relevant safety artifacts in the concept phase. Using specific diagram types, different views of the available data can be provided that reflects the specific needs of the stakeholders involved. One objective of this work is to improve the common understanding of the relevant safety aspects during the system design. The approach, which is demonstrated here from the perspective of a Tier1 supplier for an automotive battery system, covers different breakdown levels of a vehicle. The safety workflow presented here supports engineers' efforts to meet the safety standard ISO 26262 in a systematic way.

The standard ISO 26262 stipulates a “top-down” approach based on the process “V” model, by conducting a hazard analysis and risk assessment to determine the safety goals, and subsequently derives the safety requirements down to the appropriate element level. The specification of safety goals is targeted towards identified hazardous events, whereas the classification of safety requirements does not always turn out non-ambiguous. While requirement formalization turns out to be advantageous, the translation from natural language to semi-formal requirements, especially in context of ISO 26262, poses a problem. In this publication, a new approach for the formalization of safety requirements is introduced, targeting the demands of safety standard ISO 26262. Its part 8, clause 6 (“Specification and management of safety requirements”) has no dedicated work product to accomplish this challenging task.

The need for cost efficient development and shorter time to market requires reuse of safety-critical embedded systems. One main challenge for reuse approaches in a safety-critical context is to provide evidence that assumptions of the safety artifacts for the reused component are still valid in the new system definition. This paper summarizes the major findings from an explorative study conducted in order to identify the state of practice of reuse in the context of different functional safety standards. The explorative study consists of a set of questions, which have been discussed with interviewees from companies of various domains. The companies act in safety-critical domains with diverse product portfolios. We covered several points of view by interviewing persons with different background. The results of the study reveal industrial challenges, which built the input for the derivation of possible future work based on the identified practical needs.

Functional safety of automotive embedded systems is a key issue during the development process. To support the industry, the automotive functional safety standard ISO 26262 has been defined. However, there are several limitations when following the approach directly as defined in the standard. Within this work, we propose an approach for the integration and test of safety-critical systems by using system modeling techniques. The combination of two state-of-the-art modeling languages into a dedicated multi-language development process provides a direct link between all stages of the development process, thus enabling efficient safety verification and validation already during modeling phase. It supports the developer in efficient application of requirements as defined by ISO 26262, hence reducing development time and cost by providing traceable safety argumentation.