A Hierarchical Strategy for Velocity optimization of Connected Vehicles with the Existence of Multiple Traffic Lights

Eco-driving with velocity profile optimization is an significant potential way for energy saving. In this paper, a hierarchical velocity profile optimization strategy is proposed to minimize fuel consumption with the existence of multiple traffic lights. In the higher layer, by predictive use of signal phases and timing from the upcoming traffic lights, a novel method is used to determine the suitable time of arrivals and velocity to each traffic light. In the lower layer, to solve the velocity trajectory, an explicit optimal solution is obtained by combing Pontryagin's minimum principle in the framework of model predictive control (MPC). Then, simulation results indicate that the hierarchical velocity optimization strategy can improve the energy economy with highly computational efficiency.