Infusing Reachability-Based Safety into Planning and Control for Multi-agent Interactions

TL;DR

This paper integrates reachability-based safety into multi-agent planning and control, enabling robots to navigate efficiently while maintaining safety guarantees through a unified Hamilton-Jacobi reachability framework.

Contribution

It introduces a combined planning and control approach using Hamilton-Jacobi reachability to ensure safety in multi-agent interactions, with a minimally-interventional safety controller.

Findings

Ensures safety without compromising performance in multi-agent scenarios.

Provides strong safety guarantees in highway navigation tasks.

Achieves higher performance compared to other safety controllers.

Abstract

Within a robot autonomy stack, the planner and controller are typically designed separately, and serve different purposes. As such, there is often a diffusion of responsibilities when it comes to ensuring safety for the robot. We propose that a planner and controller should share the same interpretation of safety but apply this knowledge in a different yet complementary way. To achieve this, we use Hamilton-Jacobi (HJ) reachability theory at the planning level to provide the robot planner with the foresight to avoid entering regions with possible inevitable collision. However, this alone does not guarantee safety. In conjunction with this HJ reachability-infused planner, we propose a minimally-interventional multi-agent safety-preserving controller also derived via HJ-reachability theory. The safety controller maintains safety for the robot without unduly impacting planner performance. We demonstrate the benefits of our proposed approach in a multi-agent highway scenario where a robot car is rewarded to navigate through traffic as fast as possible, and we show that our approach provides strong safety assurances yet achieves the highest performance compared to other safety controllers.