Optimal Energy Saving Adaptive Cruise Control in Overtaking Scenarios for a Hybrid Electric Vehicle

The overtaking planning problem plays a crucial role to foster the adaptive cruise control (ACC) technology. It reveals extremely challenging due to critical requirements on the real-time capability of the control system and on conflicting objectives for the longitudinal speed trajectory generated over time for the Following Vehicle (e.g. in terms of maneuver efficiency, passenger comfort, energy economy). In this paper, an approach to solve this problem is proposed by developing an optimal energy saving oriented ACC algorithm for overtaking scenarios considering a hybrid electric vehicle (HEV) as the Following Vehicle. An off-line optimization based on Dynamic Programming (DP) is implemented. The proposed DP formulation aims at controlling the Following Vehicle longitudinal jerk over time to minimize the overall HEV energy consumption throughout the overtaking maneuver. Optimization constraints are considered for the inter-vehicular distance between Leader Vehicle and Following vehicle over time, and for the operational limits of the HEV powertrain components. The developed ACC algorithm is demonstrated achieving up to 4.1% energy saving and significant improvements in terms of passenger comfort in different overtaking scenarios.