Lp String Stability of Cascaded Systems: Application to Vehicle Platooning

Abstract

Abstract-Nowadays, throughput has become a limiting factor in road transport. An effective means to increase the road throughput is to employ a small intervehicle time gap using automatic vehicle-following control systems. String stability, i.e., the disturbance attenuation along the vehicle string, is considered an essential requirement for the design of those systems. However, the formal notion of string stability is not unambiguous in literature, since both stability and performance interpretations exist. Therefore, a novel definition for string stability of nonlinear cascaded systems is proposed, using input-output properties. This definition is shown to result in well-known string stability conditions for linear cascaded systems. The theoretical results are experimentally validated using a platoon of six passenger vehicles equipped with cooperative adaptive cruise control.Index Terms-Cascaded systems, cooperative adaptive cruise control (CACC), input-output stability, string stability, vehicle platoons.

Event-Triggered Control Systems Under Denial-of-Service Attacks

“…The time-constants τ 0 miet and τ 1 miet can be chosen less than or equal to the maximally 3 Observe that the flow map F as given in (9) is discontinuous in τ due to (27). However, due to the facts thatτ = 1 and the right hand-side of (27) is Lipschitz continuous, we find by means of the Carathéodory's existence theorem that this does not cause any problems in the uniqueness and existence of solutions.…”

“…and let Condition 1 be satisfied with τ 1 miet τ 0 miet τ miet withτ miet as in (28) and with f φ and φ miet as in (27) and (30), respectively. Moreover, suppose that the following three conditions hold:…”

“…As shown in [27], in the context of vehicle platooning, wireless communication between vehicles can have a significant contribution to improving traffic throughput and safety. For a platoon of two identical vehicles equipped with CACC, the functions f and g as in (9) are given by f (x, e, w) = A 11 x+A 12 e+A 13 w and g(x, e, w) = A 21 x + A 22 e + A 23 w, where…”

“…Moreover, the input w represents the control input of the leading vehicle. See, e.g., [27] for more details. For this example, we use the following parameter values τ c = 0.15,…”

Safety in Vehicle Platooning: A Systematic Literature Review

“…Control of string stability is thus a normal and intended condition, and analyzing it does not answer the question of what to do when something goes outside the bounds of normal operation. For this reason, string stability will not be considered further in this paper, but the reader is referred to already existing reviews on that subject, such as [5]. The objective of this paper is instead to complement the many results on string stability with a broader view on other aspects that also need attention in order to make safe platooning a reality.…”