Survey of Recent Results on the Effects of Actuation Lag, Communication Delay and Signal Noise in Cooperative Adaptive Cruise Control Systems

In this paper, we survey and provide a concise review of the recent results on the effects of actuation lag, communication delay and signal noise in cooperative adaptive cruise control systems (CACCs) based platooning of connected and autonomous vehicles (CAV s). These parasitic effects can profoundly impact both performance and safety of platooning. From the viewpoint of performance, a key measure is throughput which is directly related to the desired standstill spacing and the time headway for vehicle platoons that enforce a constant time headway policy (CTHP) for inter-vehicular spacing. From the viewpoint of safety, the goal is to design CTHP control algorithms and select their gains to prevent collisions during steady vehicle following and minimize them during emergency scenarios. These parasitic factors arise from both vehicle components (actuators and onboard sensors) as well as communication hardware, protocols and algorithms for encoding and decoding of communicated signals. In this article, we first define actuator lag, communication delay and noise in CACCs and provide a brief review of the common spacing policies and robust string stability criterion for CACC systems. We then provide a focused synopsis and pertinent discussions related to recent results on the effects of actuator lag, communication delay and signal noise for CACC systems.