A time and energy efficient merging control for platoon formation of connected and automated electric vehicles at on-ramps

On-ramps are one of common traffic congestion scenarios, which lead to reduced time and energy efficiency and cause range anxiety for electric vehicles. Connected and automated vehicle techniques, especially platoon techniques are conducive to relieve congestion by effective communication and control. Therefore, this paper proposes a merging control strategy for platoon formation of connected and automated electric vehicles (CAEVs) to improve time and energy efficiency at-ramps. A vehicle automatic-cluster approach based on virtual rotation classifies CAEVs into multiple clusters to avoid the excessive acceleration and to reduce computational cost. A global optimal merging algorithm is designed for a clustered CAEVs to determine the optimal merging sequence and corresponding velocity trajectory, which guarantees a clustered vehicles arrive at the merging point with consistent speed and time interval to form pre-platoons. Subsequently, a consensus-based platoon controller is structured to promptly form tightly-coupled platoons with stability from the pre-platoons. The simulation for three different traffic flow states validates the effectiveness of the proposed algorithm and demonstrates its potential to improve time and energy efficiency compared to another platoon-based merging algorithm. The stability of platoons is also verified through further simulation.