Optimal Lane-Free Crossing of CAVs Through Intersections

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 lanefree crossing of intersections as a multi-objective optimal control problem (OCP) that minimises the overall crossing time, as well as the energy consumption due to the acceleration of CAVs. The constraints that avoid collision of vehicles with each other and with road boundaries are smoothed by applying the dual problem theory of convex optimisation. The developed algorithm is capable of finding the lower boundary of the crossing time of a junction which can be used as a benchmark for comparing other intersection crossing algorithms. Simulation results show that the lane-free crossing time is better by an average of 40% as compared to the state-of-the-art reservation-based method, whilst consuming the same amount of energy. Furthermore, it is shown that the lane-free crossing time through intersections is fixed to a constant value regardless of the number of CAVs.

Sharing Traffic Priorities via Cyber–Physical–Social Intelligence: A Lane-Free Autonomous Intersection Management Method in Metaverse

“…Li and Shao [44] pointed out that intervehicle collision-avoidance constraints are the main source of difficulties in dealing with a cooperative trajectory planning problem because they are nonconvex and nondifferentiable. Amouzadi et al [45] simplified the collisionavoidance constraints in [42] via optimization-based collision avoidance (OBCA) to facilitate the solution process. However, global optimality is not achieved without a high-quality initial guess [46]; the scale of intervehicle collision-avoidance constraints is still intractable, thus, making [45] not fast enough.…”

“…Amouzadi et al [45] simplified the collisionavoidance constraints in [42] via optimization-based collision avoidance (OBCA) to facilitate the solution process. However, global optimality is not achieved without a high-quality initial guess [46]; the scale of intervehicle collision-avoidance constraints is still intractable, thus, making [45] not fast enough. I summarizes the strengths and limitations of typical AIM methods mentioned above.…”

Driving Strategy for Vehicles in Lane-Free Traffic Environment Based on Deep Deterministic Policy Gradient and Artificial Forces

“…There are several driving strategies developed for CAVs in freeway lane-free environments, including optimal control approach [11,19], potential line strategy [20], and ad-hoc vehicle movement strategy [10]. The LFT concept has also been employed in urban networks, for example, in a large roundabout [21] or urban intersection [22], and integration of vulnerable road users [23]. Moreover, LFT opens a lot of research opportunities to be explored, including vehicle flocking [24,25].…”

Model predictive control of connected vehicles under automated driving at path-free signal-free intersections

“…The numerical results demonstrated that the proposed methods could generate near-optimal trajectories for CVAD. Similarly, Amouzadi, Orisatoki and Dizqah (2022) formulated the lane-free crossing of CAVs through signal-free intersections as a nonlinear minimum-time optimal control problem. The proposed formulation used the dual problem theory for smoothing the non-convex and nondifferentiable collision avoidance constraints between CAVs and between CAVs and road boundaries.…”

“…They showed that the resulting smoothed OCP could reduce the crossing time significantly compared to a space and time discretization strategy. However, the nonlinear OCP methods presented by Ahmadi et al (2021;2022) and Amouzadi, Orisatoki and Dizqah (2022) do not consider the continuous arrival of vehicles, are off-line, and force the CVAD to have the same completion times, thus not addressing a realistic problem.…”