Optimal Coordination of Automated Vehicles at Intersections: Theory and Experiments

In this paper, we present a bilevel, model predictive controller for coordination of automated vehicles at intersections. The bilevel controller consists of a coordination level, where intersection occupancy timeslots are allocated, and a vehicle level, where the control commands for the vehicles are computed. We establish persistent feasibility and stability of the bilevel controller under some mild assumptions and derive conditions under which closed-loop collision avoidance can be ensured with bounded position uncertainty. We thereafter detail an implementation of the coordination controller on a three-vehicle test bed, where the intersection-level optimization problem is solved using a distributed Sequential Quadratic Programing method. We present and discuss results from an extensive experimental campaign, where the proposed controller was validated. The experimental results indicate the practical applicability of the bilevel controller and show that safety can be ensured for large positioning uncertainties.