Error Amplification and Disturbance Propagation in Vehicle Strings with Decentralized Linear Control

We consider the problem of controlling a string of vehicles moving in one dimension so that they all follow a lead vehicle with a constant spacing between successive vehicles. We examine the symmetric bidirectional control architecture, where the control action on a vehicle depends equally on the spacing errors with respect to its adjacent vehicles. Performance of this decentralized scheme in terms of spacing error amplification and disturbance propagation is investigated. The results established in this paper show that a symmetric bidirectional architecture with a linear controller suffers from fundamental limitations on closed loop performance that cannot be mitigated by appropriate control design.