Cooperative Adaptive Cruise Control (CACC) systems which enable vehicle following with tight inter-vehicle head-way offer unique advantage to promote transportation mobility. CACC systems are a step forward the commercially available Adaptive Cruise Control (ACC) systems as they utilize inter-vehicle wireless communication for more advanced control system design. This work studies different wireless communication topologies, i.e., receiving wireless communication from one or more preceding vehicles, and different error-regulation controllers, i.e., linear vs non-linear, for CACC. Through robot following experiments, we show that appropriately designed CACC systems can all achieve vehicle following. For emergency hard braking, however, a non-linear vehicle-following controller which generates strong braking action at short inter-vehicle distances can reduce the risk of collision.
