The effect of signal noise and latency in communicated acceleration on time headway in vehicle platooning

In this paper, we investigate the effect of signal noise and latency in communicated information in connected and autonomous vehicles. In particular, we consider the effect of communicated vehicle acceleration from the predecessor vehicle to the follower vehicle on the selection of the time headway in predecessor-follower type vehicle platooning with a constant time headway policy (CTHP). Employing a CTHP based control law for each vehicle that utilizes on-board sensors for position and velocity of the predecessor vehicle and wireless communication network for obtaining the acceleration of the predecessor vehicle, we investigate how the lower bound on the time headway is affected by signal noise and network latency. We derive constraints on the CTHP controller gains for predecessor acceleration, velocity error and spacing error and a lower bound on the time headway which will ensure string stability of the platoon under the presence of signal noise and latency in communicated acceleration from the predecessor vehicle. We provide a numerical example to illustrate the main results.

I. Introduction

There has been considerable attention paid to connected and autonomous vehicles with an increasing emphasis on throughput, mobility, and safety. Recently, through the use of modern communication protocols such as dedicated short range communications (DSRC) [1], long term evolution (LTE) [2], 5G [3], which underpin the advanced vehicular communication technologies, e.g., vehicle-to-vehicle (V2V) communication [4], advanced developments towards coop-erative adaptive cruise control (CACC) systems are being considered for platooning of multiple autonomous and connected vehicles. In contrast to adaptive cruise control (ACC), in which the velocity and distance are measured by vehicle onboard sensors (such as radars), CACC can incorporate the acceleration information of other vehicles via V2V communication to better predict the other vehicles' maneuvers and improve platooning performance.