Provably-safe autonomous navigation of traffic circles

R. Konda, E. Squires, P. Pierpaoli, M. Egerstedt, S. Coogan
IEEE Conference on Control Technology and Applications, 2019


As the decision making responsibilities of autonomous vehicles increase, they will be expected to navigate complex, unstructured environments such as traffic circles. These environments necessitate effective safety control algorithms. Control barrier functions provide such a tool for guaranteeing system safety by ensuring that control actions render a given safe set forward invariant. However, finding an appropriate control barrier function is challenging. To alleviate this challenge, we consider a nominal evasive maneuver for the system. Then a control barrier function is designed by considering the closed loop dynamics resulting from this hypothetical evasive maneuver. Using this approach, in this paper, we propose a control algorithm to navigate an autonomous vehicle through a traffic circle in the presence of other vehicles. The synthesized control barrier function is able to simultaneously ensure lane keeping while avoiding collisions with other vehicles. The solution approach is then physically demonstrated on the Robotarium remote access testbed.