String Stability towards Leader thanks to Asymmetric Bidirectional Controller

TL;DR

This paper demonstrates that an asymmetric bidirectional controller can achieve string stability in vehicle platoons under certain disturbance conditions, improving upon previous symmetric or unidirectional control strategies.

Contribution

It introduces an asymmetric bidirectional control approach that recovers string stability for interconnected vehicles with disturbances on leading units, surpassing prior symmetric control limitations.

Findings

String stability is achievable with disturbances on a small set of leading vehicles.

Symmetric bidirectional controllers do not guarantee string stability under arbitrary disturbances.

Asymmetric bidirectional control improves robustness compared to symmetric or unidirectional methods.

Abstract

This paper deals with the problem of string stability of interconnected systems with double-integrator open loop dynamics (e.g.~acceleration-controlled vehicles). We analyze an asymmetric bidirectional linear controller, where each vehicle is coupled solely to its immediate predecessor and to its immediate follower with different gains in these two directions. We show that in this setting, unlike with unidirectional or symmetric bidirectional controllers, string stability can be recovered when disturbances act only on a small ($N$-independent) set of leading vehicles. This improves existing results from the literature with this assumption. We also indicate that string stability with respect to arbitrarily distributed disturbances cannot be achieved with this controller.