An optimal coordinated merging strategy for CAVs platoon at on-ramp area

Connected and automated vehicles (CAVs) have gained widespread attention due to their advantages in safety, comfort, and efficiency. Moreover, CAVs platoon will produce greater traffic benefits in offering enhanced traffic capacity, lower emissions, and improved safety. The existing vehicle-coordinated merging strategy mainly focuses on a single CAV, with limited research on the coordinated merging for CAVs platoon. Therefore, this paper constructs a merging control structure for CAVs platoon and proposes an optimal platoon-coordinated merging control strategy, which combines ramp merging and platoon control. The strategy coordinates ramp and mainline vehicles driving and merging in the form of platoons. A globally optimal platoon merging sequence (MS) determination method is developed and an optimal control strategy is proposed to realize coordinated merging. The platoon-coordinated merging control is established considering vehicle’s constraints, and the analytical solution is derived based on Pontryagin minimum principle (PMP) and dynamic programming (DP). Asymptotic and string stability are analyzed based on Routh-Hurwitz criterion and frequency-domain method. Simulation results demonstrate that the proposed optimal platoon-coordinated merging strategy can improve traffic efficiency and driving comfort while realizing coordinated merging.