Vehicular Platoons in cyclic interconnections with constant inter-vehicle spacing

This paper investigates homogeneous vehicle platoons with cyclic, bi-directional communication maintaining a constant (velocity independent) target inter vehicle spacing. We investigate stability and disturbance amplification if the string length increases, where the vehicles utilise weighted information from multiple vehicles ahead and behind. We find a condition, independent of the linear controller used, for the weighting factors that is necessary for stability of long platoons. In the second part we investigate disturbance amplification for stable systems. We show that while string instability is unavoidable with an extended but limited range, a communication range that increases with the vehicle platoon size can lead to string stability.