Vehicle platoons with ring coupling

We design a control strategy for platoons of identical vehicles. It is assumed that each vehicle measures the distance with its immediate forward neighbor. The lead vehicle in the platoon only receives information on the position of the last vehicle in the platoon. The resulting behavior of the system is a platoon of vehicles moving at a constant velocity with constant distance between pairs of consecutive vehicles. For a class of identical controllers this solution is asymptotically stable for sufficiently small coupling strength. The concept of string stability of a platoon is discussed and applied to the proposed interconnection. Simulations show the system is well-behaved with respect to string stability. To improve the behavior, integral action is added between the first and last vehicle of the platoon. The resulting behavior is determined and its stability properties are discussed

Synchronization in a population of oscillators

Nowadays a lot of interest in Systems Theory is directed to problems in which separate systems are coupled to each other. We study the dynamics of a population of uniformly all-to-all coupled limit cycle oscillators. The oscillators are permitted to possess different natural frequencies. Our greatest interest goes out to the synchronization of such populations consisting of finitely many oscillators. This synchronized behaviour is only present if the strength of the interactions supersedes some threshold value. We try to obtain some stability properties of this behaviour

Vehicle platoons through ring coupling

In this paper, a novel strategy for the control of a string of vehicles is designed. The vehicles are coupled in a unidirectional ring at the interaction level: each vehicle is influenced by the position of its immediate forward neighbor; the first vehicle in the platoon is influenced by the position of the last vehicle. Through these interactions a cooperative behavior emerges and a platoon of vehicles moving at a constant velocity with constant inter-vehicle spacings is formed. This contrasts with more traditional control schemes where an independent leader vehicle is followed by the remaining vehicles. For this control structure, stability properties are established. The concept of string stability of a platoon is discussed and applied to the ring interconnection. Design rules are presented, showing how an appropriate choice of parameter values leads to a constant spacing or constant time headway policy. Furthermore, the scheme has a characteristic property: it maintains the platoon structure when subject to malfunctioning vehicles

Clustering conditions and the cluster formation process in a dynamical model of multidimensional attracting agents

We consider a multiagent clustering model where each agent belongs to a multidimensional space. We investigate its long term behavior, and we prove emergence of clustering behavior in the sense that the velocities of the agents approach asymptotic values, independently of the initial conditions; agents with equal asymptotic velocities are said to belong to the same cluster. We propose a set of relations governing these asymptotic velocities. These results are compared with results obtained earlier for the model with agents belonging to a one-dimensional space and are then explored for the case of an infinite number of agents. For the particular case of a spherically symmetric configuration of an infinite number of agents a rigorous analysis of the relations governing the asymptotic velocities is possible, assuming that a continuity property established for the finite case remains true for the infinite case. This leads to a characterization of the onset of cluster formation in terms of the evolution of the cluster size with varying coupling strength. A remarkable point is that the cluster formation process depends critically on the dimension of the agent state space; considering the cluster size as an order parameter, the cluster formation in the one-dimensional case may be seen as a second-order phase transition, while the multidimensional case is associated with a first-order phase transition. We provide bounds for the critical coupling strength at the onset of the cluster formation, and we illustrate the results with two examples in three dimensions