20,866 research outputs found
The Cooperative Output Regulation Problem of Discrete-Time Linear Multi-Agent Systems by the Adaptive Distributed Observer
In this paper, we first present an adaptive distributed observer for a
discrete-time leader system. This adaptive distributed observer will provide,
to each follower, not only the estimation of the leader's signal, but also the
estimation of the leader's system matrix. Then, based on the estimation of the
matrix S, we devise a discrete adaptive algorithm to calculate the solution to
the regulator equations associated with each follower, and obtain an estimated
feedforward control gain. Finally, we solve the cooperative output regulation
problem for discrete-time linear multi-agent systems by both state feedback and
output feedback adaptive distributed control laws utilizing the adaptive
distributed observer.Comment: 7 pages, 4 figure
Cooperative Global Robust Stabilization for a Class of Nonlinear Multi-Agent Systems and its Application
This paper studies the cooperative global robust stabilization problem for a
class of nonlinear multi-agent systems. The problem is motivated from the study
of the cooperative global robust output regulation problem for the class of
nonlinear multi-agent systems in normal form with unity relative degree which
was studied recently under the conditions that the switching network is
undirected and some nonlinear functions satisfy certain growth condition. We
first solve the stabilization problem by using the multiple Lyapunov functions
approach and the average dwell time method. Then, we apply this result to the
cooperative global robust output regulation problem for the class of nonlinear
systems in normal form with unity relative degree under directed switching
network, and have removed the conditions that the switching network is
undirected and some nonlinear functions satisfy certain growth condition.Comment: 9 pages, 1 figure. This paper was submitted to the journal
"Automatica
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
Cancellation and homotopy rigidity of classical functors
We first show that simply connected co--spaces and connected -spaces
can be uniquely decomposed into prime factors in the homotopy category of
pointed -local spaces of finite type, which is used to develop a -local
version of Gray's correspondence between homotopy types of prime co--spaces
and homotopy types of prime -spaces, and the split fibration which connects
them as well. Further, we use the unique decomposition theorem to study the
homotopy rigidity problem for classic functors. Among others, we prove that
and are homotopy rigid on simply connected -local
co--spaces of finite type, and and are homotopy
rigid on connected -local -spaces of finite type
Analytical solution for Klein-Gordon equation and action function of the solution for Dirac equation in counter-propagating laser waves
Nonperturbative calculation of QED processes participated by a strong
electromagnetic field, especially provided by strong laser facilities at
present and in the near future, generally resorts to the Furry picture with the
usage of analytical solutions of the particle dynamical equation, such as the
Klein-Gordon equation and Dirac equation. However only for limited field
configurations such as a plane-wave field could the equations be solved
analytically. Studies have shown significant interests in QED processes in a
strong field composed of two counter-propagating laser waves, but the exact
solutions in such a field is out of reach. In this paper, inspired by the
observation of the structure of the solutions in a plane-wave field, we develop
a new method and obtain the analytical solution for the Klein-Gordon equation
and equivalently the action function of the solution for the Dirac equation in
this field, under a largest dynamical parameter condition that there exists an
inertial frame in which the particle free momentum is far larger than the other
field dynamical parameters. The applicable range of the new solution is
demonstrated and its validity is proven clearly. The result has the advantage
of Lorentz covariance, clear structure and close similarity to the solution in
a plane-wave field, and thus favors convenient application.Comment:
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
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
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
Modified light cone condition via vacuum polarization in a time dependent field
The appearance of unconventional vacuum properties in intense fields has long
been an active field of research. In this paper the vacuum polarization effect
is investigated via a pump probe scheme of a probe light propagating in the
vacuum excited by two counter-propagating laser beams. The modified light cone
condition of the probe light is derived analytically for the situation that it
passes through the electric/magnetic antinode plane of the pump field. The
derivation does not follow the commonly adopted assumption of treating the pump
field as a constant field. Differences from the conventional light cone
conditions are identified. The implications of the result are discussed with a
consideration of the vacuum birefringence measurement.Comment: 7 pages, 0 figure
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
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