Longitudinal control of a string of vehicles using vehicle-to-vehicle communication

This paper describes a longitudinal control algorithm for a string of moving vehicles, which uses vehicle-to-vehicle communication. Each vehicle in the string is equipped with automatic velocity control, and is linked to the vehicles next to it by a local digital communication system. The vehicles travel close together in the string, and longitudinal control is achieved using a PD control algorithm cast in the form of a pole assignment problem. The algorithm requires that control signals, and position and velocity data for each vehicle be transmitted to the following vehicle. It can be shown that one-way communication is sufficient to provide the required degree of control. Simulations were performed to compare the vehicle following performance of the system to that achieved by human drivers. The simulations showed that the system prevents the traffic flow instabilities and rear-end collisions that tend to occur in a string with human drivers when the lead vehicle brakes suddenly. Longitudinal control using vehicle-to-vehicle communication therefore has the potential to increase road capacity and avoid the traffic delays that are inevitable with human drivers.