Behavior Trees in Functional Safety Supervisors for Autonomous Vehicles

The rapid advancements in autonomous vehicle software present both opportunities and challenges, especially in enhancing road safety. The primary objective of autonomous vehicles is to reduce accident rates through improved safety measures. However, the integration of new algorithms into the autonomous vehicle, such as artificial intelligence methods, raises concerns about the compliance with established safety regulations. This paper introduces a novel supervisor architecture based on behavior trees, aligned with established standards and designed to supervise vehicle functional safety in real time. It specifically addresses the integration of algorithms into industrial road vehicles, adhering to the ISO 26262. The proposed supervisor architecture involves the detection of hazards and compliance with functional and technical safety requirements when a hazard arises. This methodology, implemented in this study in a Renault Mégane (currently with SAE level 3 of automation capabilities), not only guarantees compliance with safety standards, but also paves the way for safer and more reliable autonomous driving technologies.