1,412 research outputs found
Multi-Agent Distributed Coordination Control: Developments and Directions
In this paper, the recent developments on distributed coordination control,
especially the consensus and formation control, are summarized with the graph
theory playing a central role, in order to present a cohesive overview of the
multi-agent distributed coordination control, together with brief reviews of
some closely related issues including rendezvous/alignment, swarming/flocking
and containment control.In terms of the consensus problem, the recent results
on consensus for the agents with different dynamics from first-order,
second-order to high-order linear and nonlinear dynamics, under different
communication conditions, such as cases with/without switching communication
topology and varying time-delays, are reviewed, in which the algebraic graph
theory is very useful in the protocol designs, stability proofs and converging
analysis. In terms of the formation control problem, after reviewing the
results of the algebraic graph theory employed in the formation control, we
mainly pay attention to the developments of the rigid and persistent graphs.
With the notions of rigidity and persistence, the formation transformation,
splitting and reconstruction can be completed, and consequently the range-based
formation control laws are designed with the least required information in
order to maintain a formation rigid/persistent. Afterwards, the recent results
on rendezvous/alignment, swarming/flocking and containment control, which are
very closely related to consensus and formation control, are briefly
introduced, in order to present an integrated view of the graph theory used in
the coordination control problem. Finally, towards the practical applications,
some directions possibly deserving investigation in coordination control are
raised as well.Comment: 28 pages, 8 figure
Nonlinear Consensus Strategies for Multi-Agent Networks in Presence of Communication Delays and Switching Topologies: Real-Time Receding Horizon Approach
This paper presents a novel framework which combines a non-iterative solution
of Real-Time Nonlinear Receding Horizon Control (NRHC) methodology to achieve
consensus within complex network topologies with existing time-delays and in
presence of switching topologies. In this formulation, we solve the distributed
nonlinear optimization problem for multi-agent network systems directly,
\emph{in real-time}, without any dependency on iterative processes, where the
stability and convergence guarantees are provided for the solution. Three
benchmark examples on non-linear chaotic systems provide validated results
which demonstrate the significant outcomes of such methodology.Comment: 26 pages, 8 figures (under review). arXiv admin note: substantial
text overlap with arXiv:1510.0779
Asynchronous Consensus in Continuous-Time Multi-Agent Systems With Switching Topology and Time-Varying Delays
In this paper, we study asynchronous consensus problems of continuous-time
multi-agent systems with discontinuous information transmission. The proposed
consensus control strategy is implemented only based on the state information
at some discrete times of each agent's neighbors. The asynchronization means
that each agent's update times, at which the agent adjusts its dynamics, are
independent of others'. Furthermore, it is assumed that the communication
topology among agents is time-dependent and the information transmission is
with bounded time-varying delays. If the union of the communication topology
across any time interval with some given length contains a spanning tree, the
consensus problem is shown to be solvable. The analysis tool developed in this
paper is based on the nonnegative matrix theory and graph theory. The main
contribution of this paper is to provide a valid distributed consensus
algorithm that overcomes the difficulties caused by unreliable communication
channels, such as intermittent information transmission, switching
communication topology, and time-varying communication delays, and therefore
has its obvious practical applications. Simulation examples are provided to
demonstrate the effectiveness of our theoretical results.Comment: Regular pape
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
Guaranteed-cost consensus for multiagent networks with Lipschitz nonlinear dynamics and switching topologies
Guaranteed-cost consensus for high-order nonlinear multi-agent networks with
switching topologies is investigated. By constructing a time-varying
nonsingular matrix with a specific structure, the whole dynamics of multi-agent
networks is decomposed into the consensus and disagreement parts with nonlinear
terms, which is the key challenge to be dealt with. An explicit expression of
the consensus dynamics, which contains the nonlinear term, is given and its
initial state is determined. Furthermore, by the structure property of the
time-varying nonsingular transformation matrix and the Lipschitz condition, the
impacts of the nonlinear term on the disagreement dynamics are linearized and
the gain matrix of the consensus protocol is determined on the basis of the
Riccati equation. Moreover, an approach to minimize the guaranteed cost is
given in terms of linear matrix inequalities. Finally, the numerical simulation
is shown to demonstrate the effectiveness of theoretical results.Comment: 16 page
A new framework for consensus for discrete-time directed networks of multi-agents with distributed delays
Copyright @ 2012 Taylor & FrancisIn this article, the distributed consensus problem is considered for discrete-time delayed networks of dynamic agents with fixed topologies, where the networks under investigation are directed and the time-delays involved are distributed time delays including a single or multiple time delay(s) as special cases. By using the invariance principle of delay difference systems, a new unified framework is established to deal with the consensus for the discrete-time delayed multi-agent system. It is shown that the addressed discrete-time network with arbitrary distributed time delays reaches consensus provided that it is strongly connected. A numerical example is presented to illustrate the proposed methods.This work was supported in part by City University of Hong Kong under Grant 7008114, the Royal Society of the UK, the National Natural Science Foundation of China under Grants 60774073 and 61074129, and the Natural Science Foundation of Jiangsu Province of China under Grant BK2010313
Coordinated Output Regulation of Heterogeneous Linear Systems under Switching Topologies
This paper constructs a framework to describe and study the coordinated
output regulation problem for multiple heterogeneous linear systems. Each agent
is modeled as a general linear multiple-input multiple-output system with an
autonomous exosystem which represents the individual offset from the group
reference for the agent. The multi-agent system as a whole has a group
exogenous state which represents the tracking reference for the whole group.
Under the constraints that the group exogenous output is only locally available
to each agent and that the agents have only access to their neighbors'
information, we propose observer-based feedback controllers to solve the
coordinated output regulation problem using output feedback information. A
high-gain approach is used and the information interactions are allowed to be
switched over a finite set of fixed networks containing both graphs that have a
directed spanning tree and graphs that do not. The fundamental relationship
between the information interactions, the dwell time, the non-identical
dynamics of different agents, and the high-gain parameters is given.
Simulations are shown to validate the theoretical results
Robust Consensus Tracking of Heterogeneous Multi-Agent Systems under Switching Topologies
In this paper, we consider a robust consensus tracking problem of
heterogeneous multi-agent systems with time-varying interconnection topologies.
Based on common Lyapunov function and internal model techniques, both state and
output feedback control laws are derived to solve this problem. The proposed
design is robust by admitting some parameter uncertainties in the multi-agent
system.Comment: 11 pages, 4 figures, accepte
Dynamic Feedback for Consensus of Networked Lagrangian Systems
This paper investigates the consensus problem of multiple uncertain
Lagrangian systems. Due to the discontinuity resulted from the switching
topology, achieving consensus in the context of uncertain Lagrangian systems is
challenging. We propose a new adaptive controller based on dynamic feedback to
resolve this problem and additionally propose a new analysis tool for
rigorously demonstrating the stability and convergence of the networked
systems. The new introduced analysis tool is referred to as uniform
integral-L_p stability, which is motivated for addressing integral-input-output
properties of linear time-varying systems. It is then shown that the consensus
errors between the systems converge to zero so long as the union of the graphs
contains a directed spanning tree. It is also shown that the proposed
controller enjoys the robustness with respect to constant communication delays.
The performance of the proposed adaptive controllers is shown by numerical
simulations.Comment: 7 pages, 8 figures, submitted to IEEE Transactions on Automatic
Contro
Structure-Based Self-Triggered Consensus in Networks of Multiagents with Switching Topologies
In this paper, we propose a new self-triggered consensus algorithm in
networks of multi-agents. Different from existing works, which are based on the
observation of states, here, each agent determines its next update time based
on its coupling structure. Both centralized and distributed approaches of the
algorithms have been discussed. By transforming the algorithm to a proper
discrete-time systems without self delays, we established a new analysis
framework to prove the convergence of the algorithm. Then we extended the
algorithm to networks with switching topologies, especially stochastically
switching topologies. Compared to existing works, our algorithm is easier to
understand and implement. It explicitly provides positive lower and upper
bounds for the update time interval of each agent based on its coupling
structure, which can also be independently adjusted by each agent according to
its own situation. Our work reveals that the event/self triggered algorithms
are essentially discrete and more suitable to a discrete analysis framework.
Numerical simulations are also provided to illustrate the theoretical results
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