Optimal Lane-Free Crossing of CAVs through Intersections

TL;DR

This paper introduces a convexified optimal control framework for lane-free intersection crossing of connected autonomous vehicles, significantly reducing crossing time while maintaining energy efficiency.

Contribution

It formulates a novel convex optimal control problem for lane-free CAV crossing, enabling efficient solutions and near-optimal performance regardless of vehicle count.

Findings

Reduces crossing time by approximately 40% compared to existing methods

Maintains energy consumption at levels comparable to current approaches

Crossing time remains constant regardless of the number of vehicles

Abstract

Connected and autonomous vehicles (CAVs), unlike conventional cars, will utilise the whole space of intersections and cross in a lane-free order. This paper formulates such a lane-free crossing of intersections as a multi-objective optimal control problem (OCP) that minimises the overall crossing time, as well as the energy consumption of CAVs. The proposed OCP is convexified by applying the dual problem theory to the constraints that avoid collision of vehicles with each other and with road boundaries. The resulting OCP is smooth and solvable by gradient-based algorithms. Simulation results show that the proposed algorithm reduces the crossing time by an average of 40% and 41% as compared to, respectively, the state-of-the-art reservation-based and lane-free methods, whilst consuming the same amount of energy. Furthermore, it is shown that the resulting crossing time of the proposed algorithm is i) fixed to a constant value regardless of the number of CAVs, and ii) very close to its theoretical limit.