9,187 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
Decentralized Event-Triggered Consensus over Unreliable Communication Networks
This article studies distributed event-triggered consensus over unreliable
communication channels. Communication is unreliable in the sense that the
broadcast channel from one agent to its neighbors can drop the event-triggered
packets of information, where the transmitting agent is unaware that the packet
was not received and the receiving agents have no knowledge of the transmitted
packet. Additionally, packets that successfully arrive at their destination may
suffer from time-varying communication delays. In this paper, we consider
directed graphs, and we also relax the consistency on the packet dropouts and
the delays. Relaxing consistency means that the delays and dropouts for a
packet broadcast by one agent can be different for each receiving node. We show
that even under this challenging scenario, agents can reach consensus
asymptotically while reducing transmissions of measurements based on the
proposed event-triggered consensus protocol. In addition, positive inter-event
times are obtained which guarantee that Zeno behavior does not occur.Comment: 20 pages, 5 figure
Distributed consensus of linear MASs with an unknown leader via a predictive extended state observer considering input delay and disturbances
The problem of disturbance rejection/attenuation for constant-input delayed
linear multi-agent systems (MASs) with the directed communication topology is
tackled in this paper, where a classic model reduction technique is introduced
to transform the delayed MAS into the delay-free one. First, when the leader
has no control input, a novel adaptive predictive extended state observer (ESO)
using only relative state information of neighboring agents is designed to
achieve disturbance-rejected consensus tracking. The stabilization analysis is
presented via the Lyapunov function and sufficient conditions are derived in
terms of linear matrix inequalities. Then the result is extended to the
disturbance-attenuated case where the leader has bounded control input which is
only known by a portion of followers. Finally, two numerical examples are
presented to illustrate the effectiveness of proposed strategies. The main
contribution focuses on the design of adaptive predictive ESO protocols with
the fully distributed property.Comment: 18 page
Consensus of second order multi-agents with actuator saturation and asynchronous time-delays
This article presents the consensus of a saturated second order multi-agent
system with non-switching dynamics that can be represented by a directed graph.
The system is affected by data processing (input delay) and communication
time-delays that are assumed to be asynchronous. The agents have saturation
nonlinearities, each of them is approximated into separate linear and nonlinear
elements. Nonlinear elements are represented by describing functions.
Describing functions and stability of linear elements are used to estimate the
existence of limit cycles in the system with multiple control laws. Stability
analysis of the linear element is performed using Lyapunov-Krasovskii functions
and frequency domain analysis. A comparison of pros and cons of both the
analyses with respect to time-delay ranges, applicability and computation
complexity is presented. Simulation and corresponding hardware implementation
results are demonstrated to support theoretical results.Comment: 10 page
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
Dynamic Output Feedback Guaranteed-Cost Synchronization for Multiagent Networks with Given Cost Budgets
The current paper addresses the distributed guaranteed-cost synchronization
problems for general high-order linear multiagent networks. Existing works on
the guaranteed-cost synchronization usually require all state information of
neighboring agents and cannot give the cost budget previously. For both
leaderless and leader-following interaction topologies, the current paper
firstly proposes a dynamic output feedback synchronization protocol with
guaranteed-cost constraints, which can realize the tradeoff design between the
energy consumption and the synchronization regulation performance with the
given cost budget. Then, according to different structure features of
interaction topologies, leaderless and leader-following guaranteed-cost
synchronization analysis and design criteria are presented, respectively, and
an algorithm is proposed to deal with the impacts of nonlinear terms by using
both synchronization analysis and design criteria. Especially, an explicit
expression of the synchronization function is shown for leaderless cases, which
is independent of protocol states and the given cost budget. Finally, numerical
examples are presented to demonstrate theoretical results.Comment: 12 page
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
Consensus tracking in multi agent system with nonlinear and non identical dynamics via event driven sliding modes
In this work, leader follower consensus objective has been addressed with the
synthesis of an event based controller utilizing sliding mode robust control.
The schema has been partitioned into two parts viz. finite time consensus
problem and event triggered control mechanism. A nonlinear multi agent system
with non identical dynamics has been put forward to illustrate the robust
capabilities of the proposed control. The first part incorporates matching of
states of the followers with those of the leader via consensus tracking
algorithm. In the subsequent part, an event triggered rule is devised to save
computational power and restrict periodic updating of the controller involved
while ensuring desired closed loop performance of the system. Switching of the
event based controller is achieved via sliding mode control. Advantage of using
switched controller like sliding mode is that it retains its inherent
robustness as well as event triggering approach aids in saving energy
expenditure. Efficacy of the proposed scheme is confirmed via numerical
simulations.Comment: preprint, "IEEE Transactions on Automatic Control
Coordination Control of Heterogeneous Compounded-Order Multi-Agent Systems with Communication Delays
Since the complexity of the practical environment, many distributed networked
systems can not be illustrated with the integer-order dynamics and only be
described as the fractional-order dynamics. Suppose multi-agent systems will
show the individual diversity with difference agents, where the heterogeneous
(integer-order and fractional-order) dynamics are used to illustrate the agent
systems and compose integer-fractional compounded-order systems. Applying
Laplace transform and frequency domain theory of the fractional-order operator,
consensus of delayed multi-agent systems with directed weighted topologies is
studied. Since integer-order model is the special case of fractional-order
model, the results in this paper can be extend to the systems with
integer-order models. Finally, numerical examples are used to verify our
results.Comment: 15pages, 4figure
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