13,838 research outputs found
Internal Model Approach to Cooperative Robust Output Regulation for Linear Uncertain Time-Delay Multi-Agent Systems
In this paper, we study the cooperative robust output regulation problem for
linear uncertain multi-agent systems with both communication delay and input
delay by the distributed internal model approach. The problem includes the
leader-following consensus problem of linear multi-agent systems with
time-delay as a special case. We first generalize the internal model design
method to systems with both communication delay and input delay. Then, under a
set of standard assumptions, we have obtained the solution of the problem via
both the state feedback control and the output feedback control. In contrast
with the existing results, our results apply to general uncertain linear
multi-agent systems, accommodate a large class of leader signals, and achieve
the asymptotic tracking and disturbance rejection at the same time.Comment: 15 pages, 3 figure
Distributed Output Regulation for a Class of Nonlinear Multi-Agent Systems with Unknown-Input Leaders
In this paper, a distributed output regulation problem is formulated for a
class of uncertain nonlinear multi-agent systems subject to local disturbances.
The formulation is given to study a leader-following problem when the leader
contains unknown inputs and its dynamics is different from those of the
followers. Based on the conventional output regulation assumptions and graph
theory, distributed feedback controllers are constructed to make the agents
globally or semi-globally follow the uncertain leader even when the bound of
the leader's inputs is unknown to the followers.Comment: 8 pages, 2 figure
Coordination of Multi-Agent Systems under Switching Topologies via Disturbance Observer Based Approach
In this paper, a leader-following coordination problem of heterogeneous
multi-agent systems is considered under switching topologies where each agent
is subject to some local (unbounded) disturbances. While these unknown
disturbances may disrupt the performance of agents, a disturbance observer
based approach is employed to estimate and reject them. Varying communication
topologies are also taken into consideration, and their byproduct difficulties
are overcome by using common Lyapunov function techniques. According to the
available information in difference cases, two disturbance observer based
protocols are proposed to solve this problem. Their effectiveness is verified
by simulations.Comment: 12 pages, 4 figures, 2 table
Adaptive Leader-Following Consensus for a Class of Higher-Order Nonlinear Multi-Agent Systems with Directed Switching Networks
In this paper, we study the leader-following consensus problem for a class of
uncertain nonlinear multi-agent systems under jointly connected directed
switching networks. The uncertainty includes constant unbounded parameters and
external disturbances. We first extend the recent result on the adaptive
distributed observer from global asymptotical convergence to global exponential
convergence. Then, by integrating the conventional adaptive control technique
with the adaptive distributed observer, we present our solution by a
distributed adaptive state feedback control law. Our result is illustrated by
the leader-following consensus problem for a group of van der Pol oscillators.Comment: 21 pages, 5 figures. In this replacement version, the higher-order
case is considered instead of the second-order case. Also, the main
difference of this version from the reference [16] is that Appendix B is
added to show the existence of the limit of the function V(t) defined in the
equation (33) as t tends to infinit
Cooperative Global Robust Output Regulation for a Class of Nonlinear Multi-Agent Systems by Distributed Event-Triggered Control
This paper studies the event-triggered cooperative global robust output
regulation problem for a class of nonlinear multi-agent systems via a
distributed internal model design. We show that our problem can be solved
practically in the sense that the ultimate bound of the tracking error can be
made arbitrarily small by adjusting a design parameter in the proposed
event-triggered mechanism. Our result offers a few new features. First, our
control law is robust against both external disturbances and parameter
uncertainties, which are allowed to belong to some arbitrarily large prescribed
compact sets. Second, the nonlinear functions in our system do not need to
satisfy the global Lipchitz condition. Thus our systems are general enough to
include some benchmark nonlinear systems that cannot be handled by existing
approaches. Finally, our control law is a specific distributed output-based
event-triggered control law, which lends itself to a direct digital
implementation.Comment: This paper has been submitted to a journal on July 17, 201
On Distributed Internal Model Principle for Output Regulation over Time-Varying Networks of Linear Heterogeneous Agents
We study a multi-agent output regulation problem, where not all agents have
access to the exosystem's dynamics. We propose a distributed controller that
solves the problem for linear, heterogeneous, and uncertain agent dynamics as
well as time-varying directed networks. The distributed controller consists of
two parts: (1) an exosystem generator that creates a local copy of the
exosystem dynamics by using consensus protocols, and (2) a dynamic compensator
that uses (again) consensus to approach the internal model of the exosystem and
thereby achieves perfect output regulation. Our approach leverages methods from
internal model based controller synthesis, multi-agent consensus over directed
networks, and stability of time-varying linear systems; the derived result is
an adaptation of the (centralized) internal model principle to the distributed,
networked setting
Event-Triggered Cooperative Robust Practical Output Regulation for a Class of Linear Multi-Agent Systems
In this paper, we consider the event-triggered cooperative robust practical
output regulation problem for a class of linear minimum-phase multi-agent
systems. We first convert our problem into the cooperative robust practical
stabilization problem of a well defined augmented system Based on the
distributed internal model approach. Then, we design a distributed
event-triggered output feedback control law together with a distributed
output-based event-triggered mechanism to stabilize the augmented system, which
leads to the solvability of the cooperative robust practical output regulation
problem of the original plant. Our distributed control law can be directly
implemented in a digital platform provided that the distributed triggering
mechanism can monitor the continuous-time output information from neighboring
agents. Finally, we illustrate our design by an example.Comment: This paper has been accepted for publication in Automatica on May 21,
201
Cooperative Robust Output Regulation Problem for Discrete-Time Linear Time-Delay Multi-Agent Systems
In this paper, we study the cooperative robust output regulation problem for
discrete-time linear multi-agent systems with both communication and input
delays by distributed internal model approach. We first introduce the
distributed internal model for discrete-time multi-agent systems with both
communication and input delays. Then, we define so-called auxiliary system and
auxiliary augmented system. Finally, we solve our problem by showing, under
some standard assumptions, that if a distributed state feedback control or a
distributed output feedback control solves the robust output regulation problem
of the auxiliary system, then the same control law solves the cooperative
robust output regulation problem of the original multi-agent systems.Comment: arXiv admin note: text overlap with arXiv:1508.0420
Gain-scheduled Leader-follower Tracking Control for Interconnected Parameter Varying Systems
This paper considers the gain-scheduled leader-follower tracking control
problem for a parameter varying complex interconnected system with directed
communication topology and uncertain norm-bounded coupling between the agents.
A gain-scheduled consensus-type control protocol is proposed and a sufficient
condition is obtained which guarantees a suboptimal bound on the system
tracking performance under this protocol. An interpolation technique is used to
obtain a protocol schedule which is continuous in the scheduling parameter. The
effectiveness of the proposed method is demonstrated using a simulation
example
Adaptive Leader-Following Consensus for Uncertain Euler-Lagrange Systems under Directed Switching Networks
The leader-following consensus problem for multiple Euler-Lagrange systems
was studied recently by the adaptive distributed observer approach under the
assumptions that the leader system is neurally stable and the communication
network is jointly connected and undirected. In this paper, we will study the
same problem without assuming that the leader system is neutrally stable, and
the communication network is undirected. The effectiveness of this new result
will be illustrated by an example
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