This paper presents a car-following control strategy of connected automated vehicles (CAVs) to stabilize a mixed vehicular platoon consisting of CAVs and human-driven vehicles. This study first establishes a string stability criterion for a mixed vehicular platoon. Specifically, a mixed vehicular platoon is decomposed into “subsystems” that are all possible sequential subsets of the platoon. String stability is then defined as the “head-to-tail” string stability for all subsystems: the magnitude of a disturbance is not amplified from the first vehicle to the last vehicle of each subsystem. Based on this definition, distributed frequency-domain-based CAV control is proposed to increase the number of head-to-tail string stable subsystems and consequently dampen stop-and-go disturbances drastically. Specifically, an H-infinity control problem is formulated, where the maximum disturbance “damping ratios” in each subsystem is minimized within the predominant acceleration frequency boundaries of human-driven vehicles. Simulation experiments, embedded with real human-driven vehicle trajectories, were conducted, and results show that the proposed control can effectively dampen stop-and-go disturbances.

本文提出了一种连接自动驾驶汽车（CAV）的跟随汽车的控制策略，以稳定由CAV和人类驾驶汽车组成的混合车辆排。这项研究首先建立了混合车辆排的弦稳定性标准。具体来说，将混合的车辆排分解为“子系统”，这些“子系统”都是排的所有可能的顺序子集。然后，将琴弦稳定性定义为所有子系统的“头对尾”琴弦稳定性：扰动的幅度不会从每个子系统的第一个车辆传播到最后一个车辆。基于此定义，提出了基于频域的分布式CAV控制，以增加头对尾字符串稳定子系统的数量，从而极大地抑制走走停停的干扰。特别，提出了H无限控制问题，其中在人类驾驶车辆的主要加速度频率范围内，每个子系统中的最大干扰“阻尼比”被最小化。进行了仿真实验，并嵌入了真实的人类驱动的车辆轨迹，结果表明，所提出的控制可以有效地抑制走走停停的干扰。