Constant spacing strategies for platooning in Automated Highway Systems

An important aspect of an Automated Highway System is automatic vehicle fol lowing. Automatic Vehicle follower systems must address the problem of stri ng stability, i.e., the problem of spacing error propagation, and in some c ases, amplification upstream from one vehicle to another, due to some distu rbance at the head of the platoon. An automatic vehicle following controlle r design that is (asymptotically) stable for one vehicle following another is not necessarily (asymptotically) stable for a string of vehicles. The dy namic coupling between vehicles in such close-formation platoons is a funct ion of the available information (communicated as well as sensed), decentra lized feedback control laws and the vehicle spacing policy in use. In the f irst half of this paper, we develop a framework for establishing conditions for stability of the string in the presence of such dynamic interactions. We then develop a metric for analyzing the performance of a platoon resulti ng from different vehicle following control algorithms. This metric is the guaranteed rate of attenuation/non-amplification of spacing errors from one vehicle to another. in the latter half of this paper, we outline and analy ze various constant spacing vehicle follower algorithms. All these algorith ms are analyzed for sensing/actuation fags.