Design of the Communication Structure of Cooperative Adaptive Cruise Controllers

Abstract

The paper considers the cooperative adaptive cruise control of vehicle platoons and proposes a systematic way to find the local vehicle controllers and the communication structure. It investigates under what conditions the controlled vehicles follow asymptotically the time-headway spacing policy. The result is a requirement on the vehicle delay, which is a quantity that is directly related to the dynamics of the controlled vehicles and describes how much time the vehicles need to follow a change of the velocity set-point. If the vehicle delay is too large, communication from vehicles ahead improve the performance of the vehicle within the platoon. It is proved that in order to guarantee collision avoidance in the platoon, the truncated platoons have to be externally positive. Hence, the vehicle controllers have to be designed with the two, partly contradictory objectives to make the vehicle delay as small as possible and to end up with externally positive vehicles. It is investigated how vehicles with velocity controller or combined distance and velocity controller can satisfy these objectives.