5,884 research outputs found
Containment Control of Second-order Multi-agent Systems Under Directed Graphs and Communication Constraints
The distributed coordination problem of multi-agent systems is addressed in
this paper under the assumption of intermittent communication between agents in
the presence of time-varying communication delays. Specifically, we consider
the containment control problem of second-order multi-agent systems with
multiple dynamic leaders under a directed interconnection graph topology. Also,
communication between agents is performed only at some discrete instants of
time in the presence of irregular communication delays and packet dropout.
First, we present distributed control algorithms for double integrator dynamics
in the full and partial state feedback cases. Then, we propose a method to
extend our results to second-order systems with locally Lipschitz nonlinear
dynamics. In both cases, we show that the proposed approach leads to our
control objectives under sufficient conditions relating the characteristics of
the communication process and the control gains. We also show that our approach
can be applied to solve various similar coordination problems in multi-agent
systems under the same communication constraints. The effectiveness of the
proposed control schemes is illustrated through some examples and numerical
simulations.Comment: Modified version. Paper submitted for publicatio
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
Task-space coordinated tracking of multiple heterogeneous manipulators via controller-estimator approaches
This paper studies the task-space coordinated tracking of a time-varying
leader for multiple heterogeneous manipulators (MHMs), containing redundant
manipulators and nonredundant ones. Different from the traditional coordinated
control, distributed controller-estimator algorithms (DCEA), which consist of
local algorithms and networked algorithms, are developed for MHMs with
parametric uncertainties and input disturbances. By invoking differential
inclusions, nonsmooth analysis, and input-to-state stability, some conditions
(including sufficient conditions, necessary and sufficient conditions) on the
asymptotic stability of the task-space tracking errors and the subtask errors
are developed. Simulation results are given to show the effectiveness of the
presented DCEA.Comment: 17 pages, 7 figures, Journal of the Franklin Institut
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
On the Synchronization of Second-Order Nonlinear Systems with Communication Constraints
This paper studies the synchronization problem of second-order nonlinear
multi-agent systems with intermittent communication in the presence of
irregular communication delays and possible information loss. The control
objective is to steer all systems' positions to a common position with a
prescribed desired velocity available to only some leaders. Based on the
small-gain framework, we propose a synchronization scheme relying on an
intermittent information exchange protocol in the presence of time delays and
possible packet dropout. We show that our control objectives are achieved with
a simple selection of the control gains provided that the directed graph,
describing the interconnection between all systems (or agents), contains a
spanning tree. The example of Euler-Lagrange systems is considered to
illustrate the application and effectiveness of the proposed approach.Comment: 21 pages, 8 figures. Submitted for journal publicatio
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 unified framework of fully distributed adaptive output time-varying formation control for linear multi-agent systems: an observer viewpoint
This paper presents a unified framework of time-varying formation (TVF)
design for general linear multi-agent systems (MAS) based on an observer
viewpoint from undirected to directed topology, from stabilization to tracking
and from a leader without input to a one with bounded input. The followers can
form a TVF shape which is specified by piecewise continuously differential
vectors. The leader's trajectory, which is available to only a subset of
followers, is also time-varying. For the undirected formation tracking and
directed formation stabilization cases, only the relative output measurements
of neighbors are required to design control protocols; for the directed
formation tracking case, the agents need to be introspective (i.e. agents have
partial knowledge of their own states) and the output measurements are
required. Furthermore, considering the real applications, the leader with
bounded input case is studied. One main contribution of this paper is that
fully distributed adaptive output protocols, which require no global
information of communication topology and do not need the absolute or relative
state information, are proposed to solve the TVF control problem. Numerical
simulations including an application to nonholonomic mobile vehicles are
provided to verify the theoretical results.Comment: 21 page
Adaptive guaranteed-performance consensus design for high-order multiagent systems
The current paper addresses the distributed guaranteed-performance consensus
design problems for general high-order linear multiagent systems with
leaderless and leader-follower structures, respectively. The information about
the Laplacian matrix of the interaction topology or its minimum nonzero
eigenvalue is usually required in existing works on the guaranteed-performance
consensus, which means that their conclusions are not completely distributed. A
new translation-adaptive strategy is proposed to realize the completely
distributed guaranteed-performance consensus control by using the structure
feature of a complete graph in the current paper. For the leaderless case, an
adaptive guaranteed-performance consensualization criterion is given in terms
of Riccati inequalities and a regulation approach of the consensus control gain
is presented by linear matrix inequalities. Extensions to the leader-follower
cases are further investigated. Especially, the guaranteed-performance costs
for leaderless and leader-follower cases are determined, respectively, which
are associated with the intrinsic structure characteristic of the interaction
topologies. Finally, two numerical examples are provided to demonstrate
theoretical results
Navigation Function Based Decentralized Control of A Multi-Agent System with Network Connectivity Constraints
A wide range of applications require or can benefit from collaborative
behavior of a group of agents. The technical challenge addressed in this
chapter is the development of a decentralized control strategy that enables
each agent to independently navigate to ensure agents achieve a collective goal
while maintaining network connectivity. Specifically, cooperative controllers
are developed for networked agents with limited sensing and network
connectivity constraints. By modeling the interaction among the agents as a
graph, several different approaches to address the problems of preserving
network connectivity are presented, with the focus on a method that utilizes
navigation function frameworks. By modeling network connectivity constraints as
artificial obstacles in navigation functions, a decentralized control strategy
is presented in two particular applications, formation control and rendezvous
for a system of autonomous agents, which ensures global convergence to the
unique minimum of the potential field (i.e., desired formation or desired
destination) while preserving network connectivity. Simulation results are
provided to demonstrate the developed strategy.Comment: 16 pages, 9 figures, submitted to NATO Science for Peace and Security
Series by IOS Press. arXiv admin note: substantial text overlap with
arXiv:1402.563
An Output-Feedback Control Approach to the Consensus Integrated with Transient Performance Improvement Problem
This paper considers the consensus performance improvement problem of
networked general linear agents subject to external disturbances over Markovian
randomly switching communication topologies. The consensus control laws can
only use its local output information. Firstly, a class of full-order
observer-based control protocols is proposed to solve this problem, which
depends solely on the relative outputs of neighbours. Then, to eliminate the
redundancy involved in the full-order observer, a class of reduced-order
observer-based control protocols is designed. Algorithms to construct both
protocols are presented, which guarantee that agents can reach consensus in the
asymptotic mean square sense when they are not perturbed by disturbances, and
that they have decent performance and transient performance when
the disturbances exist. At the end of this manuscript, numerical simulations
which apply both algorithms to four networked Raptor-90 helicopters are
performed to verify the theoretical results
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