DSpace Collection:
http://hdl.handle.net/2117/3230
20140417T01:50:22ZOn the cuckersmale flocking model applied to a formation moving in a central force field around the Earth
http://hdl.handle.net/2117/22420
Title: On the cuckersmale flocking model applied to a formation moving in a central force field around the Earth
Authors: Paita, Fabrizio; Gomez Muntaner, Gerard; Masdemont Soler, Josep
Abstract: The Cucker – Smale (CS) flocking model is an interacting particles control system where every particle adjusts
its dynamics according to a weighted average between its velocity and those of the other elements of the flock.
Under this model, a rigid body configuration can be achieved exponentially fast for suitable initial configurations.
Furthermore, as shown by J. Shen, if the dynamics of the formation is driven by the presence of a free willed leader
then similar asymptotic results can be obtained. In the present paper we extend the CS control law in the context of a
multi – spacecraft system moving around a central body. Some new analytical results are given, as well as the results
of the numerical explorations that have been done to evaluate the performances of the control law, with particular
attention to its interaction with a central gravitational field. These performances have been evaluated mainly through
the use of two indicators: the evolution of the relative spacecrafts distances and the total fuel expended to maintain
the formation.20140327T19:10:58ZEstructuras Ainfinito en la opérada de cactus
http://hdl.handle.net/2117/22097
Title: Estructuras Ainfinito en la opérada de cactus
Authors: Gálvez Carrillo, Maria Immaculada; Lombardi, Leandro; Tonks, Andrew
Abstract: Diversas versiones de la opérada de cactus inicialmente definida por Voronov han sido estudiadas. Es conocida su equivalencia débil con la opérada de pequeños discos. Se conoce pues que la opérada de cactus admite una acción de la opérada de Gerstenhaber salvo homotopía. En este proyecto, nuestro objetivo es obtener una realización explícita de dicha acción. Por el momento, hemos construido una acción explícita de la opérada A8 en la opérada de cactus, que presentamos en este pósterJet Transport propagation of uncertainties for orbits around the Earth
http://hdl.handle.net/2117/21808
Title: Jet Transport propagation of uncertainties for orbits around the Earth
Authors: Pérez, Daniel; Masdemont Soler, Josep; Gómez Muntané, Gerard
Abstract: In this paper we present a tool to study the nonlinear propagation of uncertainties for orbits around the Earth.
The tool we introduce is known as Jet Transport and allows to propagate full neighborhoods of initial states instead of
a single initial state by means of usual numerical integrators. The description of the transported neighborhood is ob
tained in a semianalytical way by means of polynomials in 6 variables. These variables correspond to displacements
in the phase space from the reference point selected in an orbit as initial condition. The basis of the procedure is a
standard numerical integrator of ordinary differential equations (such as a RungeKutta or a Taylor method) where
the usual arithmetic is replaced by a polynomial arithmetic. In this way, the solution of the variational equations is
also obtained up to high order. This methodology is applied to the propagation of satellite trajectories and to the
computation of images of uncertainty ellipsoids including high order nonlinear descriptions. The procedure can be
specially adapted to the determination of collision probabilities with catalogued space debris or for the end of life
analysis of spacecraft in Medium Earth Orbits20140228T11:24:37ZEndoflife disposal of libration point orbit spacecraft
http://hdl.handle.net/2117/21807
Title: Endoflife disposal of libration point orbit spacecraft
Authors: Olikara, Zubin; Gómez Muntané, Gerard; Masdemont Soler, Josep
Abstract: In this work we investigate endoflife trajectories for
spacecraft in orbit about the SunEarth
L
1
and
L
2
libration points. A plan for decommission is often re
quired during the mission design process. We study
the spacecraft's natural dynamics in both a high
delity model and the circular restricted threebody
problem. In particular, we consider the role of the
unstable manifold and forbidden regions in determin
ing disposal outcomes. A simple maneuver scheme
to prevent returns to the Earth vicinity is also an
alyzed. We include discussion on potential collision
orbit schemes.20140228T11:10:49ZA note on the dynamics around the Lagrange points of the EarthMoon system in a complete Solar System model
http://hdl.handle.net/2117/21806
Title: A note on the dynamics around the Lagrange points of the EarthMoon system in a complete Solar System model
Authors: Lian, Yijun; Gómez Muntané, Gerard; Masdemont Soler, Josep; Tang, Guojian
Abstract: This paper studies the dynamics of a massless particle around the
libration points of the Earth

Moon system in a
full Solar System gravitational
model. The study is based on the analysis of the quasi

periodic solutions around the
equilibrium points. For the analysis and computation of the quasi

periodic orbits, a novel iterative algorithm is
introduced which is
a combination of
the
multiple shooti
ng method
and
a refined Fourier analysis of the orbits
computed with the multiple shooting. Using as initial seeds the libration point orbits of Circular Restricted Three
Body Problem, determined by Lindstedt

Poincar
é
methods, the procedure is able to refi
ne them in a complete Solar
System model for large time

spans covering most of the relevant Sun

Earth

Moon periods. For the collinear points,
the developed approach works well and reveals the strong relevance of the phase space around the equilibrium point
s
in both models. For the triangular points, difficulties appear and an intermediate model (bicircular model, BCM) is
introduced to aid the refinement.20140228T10:59:44ZDifferentiable families of stabilizers for planar bimodal linear control systems
http://hdl.handle.net/2117/21740
Title: Differentiable families of stabilizers for planar bimodal linear control systems
Authors: Ferrer Llop, Josep; Magret Planas, Maria dels Dolors; Peña Carrera, Marta
Abstract: We consider bimodal linear control systems consisting of two subsystems acting on each side of a given hyperplane,
assuming continuity along the separating hyperplane. For a differentiable family of controllable planar ones, we construct a
differentiable family of feedbacks which pointwise stabilizes both subsystems.20140225T09:03:00ZStructural stability of planar bimodal linear systems
http://hdl.handle.net/2117/21739
Title: Structural stability of planar bimodal linear systems
Authors: Ferrer Llop, Josep; Peña Carrera, Marta; Susín Sánchez, Antonio
Abstract: We consider bimodal linear dynamical systems consisting of two linear dynamics acting on each side of a given
hyperplane, assuming continuity along the separating hyperplane. Focusing in the planar case, we describe which of these
systems are structurally stable.20140225T08:57:11ZCyclic codes as hyperinvariant subspaces
http://hdl.handle.net/2117/21689
Title: Cyclic codes as hyperinvariant subspaces
Authors: García Planas, María Isabel; Magret Planas, Maria dels Dolors; Montoro López, Maria Eulalia
Abstract: It is known the relationship between cyclic codes and
invariant subspaces. We present in this work some
codes which are obtained from invariant and hyperinvariant
subspaces of the linear maps having associated
matrices, in the standard basis, of a special form. xxx20140221T11:11:04ZPerturbation analysis of simple eigenvalues of singular linear systems
http://hdl.handle.net/2117/21567
Title: Perturbation analysis of simple eigenvalues of singular linear systems
Authors: Tarragona Romero, Sonia; García Planas, María Isabel
Abstract: In this work a study of the behavior of a simple
eigenvalue of singular linear system family
E
(
p
)_
x
=
A
(
p
)
x
+
B
(
p
)
u
,
y
=
C
(
p
)
x
smoothly dependent on
a vector of real parameters
p
= (
p
1
;:::;p
n
)
is pre
sented20140213T10:44:30ZVersal deformations of bilinear systems under outputinjection equivalence
http://hdl.handle.net/2117/21507
Title: Versal deformations of bilinear systems under outputinjection equivalence
Authors: García Planas, María Isabel
Abstract: Bilinear systems under output injection equivalence
are considered. The aim of this paper is to study what
happens when a slight perturbation affects the coeffi
cients of the matrices defining a bilinear equation in
C
n
. For this goal we will use the Arnold’s techniques,
that is to say we will construct a versal deformation of a
differentiable family of bilinear systems which are the
orthogonal linear varieties to the orbits of output injec
tion equivalent bilinear systems. Versal deformations
provide a special parametrization of bilinear systems
space, which can be applied to perturbation analysis
and investigation of complicated objects like singular
ities and bifurcations in multiparameter bilinear sys
tems20140211T09:31:38ZFunctional outputcontrollability analysis of fixed speed wind turbine
http://hdl.handle.net/2117/21506
Title: Functional outputcontrollability analysis of fixed speed wind turbine
Authors: Domínguez García, José Luis; García Planas, María Isabel
Abstract: This paper deals with the concepts of functional
outputcontrollability character of a finitedimensional
linear dynamical system. And a method for comput
ing the functional outputcontrollability consisting on
the calculation of the rank of a certain constant ma
trix related to the system dynamics is introduced. The
linear system under study is a fixed speed wind tur
bine (FSWT) formed by a squirrel cage generator con
nected directly to the grid. Due to the nonlinear be
haviour of such system, the linear system model is
calculated by means of a Taylor’s decomposition of
the nonlinear equations of the squirrel cage induction
generator, being the system linearized around a steady
state operating point. Finally, the study of the func
tional outputcontrollability of such system is done,
and some boundaries are given to ensure functional
outputcontrollability from some given operational val
ues20140211T09:27:09ZAnalysis of support structure of wind turbine tower
http://hdl.handle.net/2117/21505
Title: Analysis of support structure of wind turbine tower
Authors: Mediano Valiente, Begoña; Domínguez García, José Luis; García Planas, María Isabel
Abstract: Wind turbines are being used to generate electricity as
an alternative energy source to conventional fossil fu
els, and it is well known that wind towers must to sus
tain continuous vibration forces throughout their opera
tional life. In this paper, a stability analysis of bending
deflection of a wind turbine steel tower is presented.
The wind turbine is modelled as the structure of a sim
plified beamcolumn by a switched system. It is mod
elled by using a Hamiltonian system, which simplifies
the system under study and allows to analyze the sta
bility dynamics of the system. An eigenvalue analysis
have been done in order to analyze the stability of the
system; finally, also, some transient simulations of the
system are presented to verify the results obtained20140211T09:22:01ZDecoding algorithm for convolutional codes under linear systems point of view
http://hdl.handle.net/2117/21238
Title: Decoding algorithm for convolutional codes under linear systems point of view
Authors: García Planas, María Isabel; Souidi, El Mamoun; Um, Laurence Emilie
Abstract: In this work the outputobservability of convolutional codes is examined and a decoding algorithm for
convolutional codes using linear algebra techniques is presented.20140115T09:20:47ZLayer solutions for the fractional Laplacian on hyperbolic space
http://hdl.handle.net/2117/20564
Title: Layer solutions for the fractional Laplacian on hyperbolic space
Authors: González Nogueras, María del Mar
Abstract: The workshop dealt with partial differential equations in ge
om
etry and technical applications. The main topics were the co
mbination of
nonlinear partial differential equations and geometric pro
blems, and fourth
order equations in conformal geometry.20131108T12:01:45ZFast numerical computation of Lissajous and quasihalo libration point trajectories
http://hdl.handle.net/2117/17854
Title: Fast numerical computation of Lissajous and quasihalo libration point trajectories
Authors: Mondelo, Josep Maria; Barrabes, E.; Gómez Muntané, Gerard; Ollé Torner, Mercè
Abstract: In this paper we present a methodology for the automatic generation of quasi–periodic libration point trajectories
(Lissajous and quasi–halo) of the Spatial, Circular Restricted Three–Body Problem. This methodology is based
on the computation of a mesh of orbits which, using interpolation strategies, gives an accurate quantitative representation
of the full set of libration point orbits. This representation, when combined with the one obtained using
Poincar´e maps, provides a useful tool for the design of missions to libration points fulfilling specific requirements.
The same methodology applies to stable and unstable manifolds as well. This paper extends and improves results
presented in [10].20130218T15:32:39Z