242 research outputs found
The Most Exigent Eigenvalue: Guaranteeing Consensus under an Unknown Communication Topology and Time Delays
This document aims to answer the question of what is the minimum delay value
that guarantees convergence to consensus for a group of second order agents
operating under different protocols, provided that the communication topology
is connected but unknown. That is, for all the possible communication
topologies, which value of the delay guarantees stability? To answer this
question we revisit the concept of most exigent eigenvalue, applying it to two
different consensus protocols for agents driven by second order dynamics. We
show how the delay margin depends on the structure of the consensus protocol
and the communication topology, and arrive to a boundary that guarantees
consensus for any connected communication topology. The switching topologies
case is also studied. It is shown that for one protocol the stability of the
individual topologies is sufficient to guarantee consensus in the switching
case, whereas for the other one it is not
Distributed Consensus of Linear Multi-Agent Systems with Switching Directed Topologies
This paper addresses the distributed consensus problem for a linear
multi-agent system with switching directed communication topologies. By
appropriately introducing a linear transformation, the consensus problem is
equivalently converted to a stabilization problem for a class of switched
linear systems. Some sufficient consensus conditions are then derived by using
tools from the matrix theory and stability analysis of switched systems. It is
proved that consensus in such a multi-agent system can be ensured if each agent
is stabilizable and each possible directed topology contains a directed
spanning tree. Finally, a numerical simulation is given for illustration.Comment: The paper will be presented at the 2014 Australian Control Conference
(AUCC 2014), Canberra, Australi
Distributed Control for Multiagent Consensus Motions with Nonuniform Time Delays
This paper solves control problems of agents achieving consensus motions in presence of nonuniform time delays by obtaining the maximal tolerable delay value. Two types of consensus motions are considered: the rectilinear motion and the rotational motion. Unlike former results, this paper has remarkably reduced conservativeness of the consensus conditions provided in such form: for each system, if all the nonuniform time delays are bounded by the maximal tolerable delay value which is referred to as “delay margin,” the system will achieve consensus motion; otherwise, if all the delays exceed the delay margin, the system will be unstable. When discussing the system which is intended to achieve rotational consensus motion, an expanded system whose state variables are real numbers (those of the original system are complex numbers) is introduced, and corresponding consensus condition is given also in the form of delay margin. Numerical examples are provided to illustrate the results
Second-Order Consensus of Networked Mechanical Systems With Communication Delays
In this paper, we consider the second-order consensus problem for networked
mechanical systems subjected to nonuniform communication delays, and the
mechanical systems are assumed to interact on a general directed topology. We
propose an adaptive controller plus a distributed velocity observer to realize
the objective of second-order consensus. It is shown that both the positions
and velocities of the mechanical agents synchronize, and furthermore, the
velocities of the mechanical agents converge to the scaled weighted average
value of their initial ones. We further demonstrate that the proposed
second-order consensus scheme can be used to solve the leader-follower
synchronization problem with a constant-velocity leader and under constant
communication delays. Simulation results are provided to illustrate the
performance of the proposed adaptive controllers.Comment: 16 pages, 5 figures, submitted to IEEE Transactions on Automatic
Contro
An Overview of Recent Progress in the Study of Distributed Multi-agent Coordination
This article reviews some main results and progress in distributed
multi-agent coordination, focusing on papers published in major control systems
and robotics journals since 2006. Distributed coordination of multiple
vehicles, including unmanned aerial vehicles, unmanned ground vehicles and
unmanned underwater vehicles, has been a very active research subject studied
extensively by the systems and control community. The recent results in this
area are categorized into several directions, such as consensus, formation
control, optimization, task assignment, and estimation. After the review, a
short discussion section is included to summarize the existing research and to
propose several promising research directions along with some open problems
that are deemed important for further investigations
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