136 research outputs found
The rolling problem: overview and challenges
In the present paper we give a historical account -ranging from classical to
modern results- of the problem of rolling two Riemannian manifolds one on the
other, with the restrictions that they cannot instantaneously slip or spin one
with respect to the other. On the way we show how this problem has profited
from the development of intrinsic Riemannian geometry, from geometric control
theory and sub-Riemannian geometry. We also mention how other areas -such as
robotics and interpolation theory- have employed the rolling model.Comment: 20 page
Submersions, Hamiltonian systems and optimal solutions to the rolling manifolds problem
Given a submersion with an Ehresmann connection ,
we describe how to solve Hamiltonian systems on by lifting our problem to
. Furthermore, we show that all solutions of these lifted Hamiltonian
systems can be described using the original Hamiltonian vector field on
along with a generalization of the magnetic force. This generalized force is
described using the curvature of along with a new form of
parallel transport of covectors vanishing on . Using the
Pontryagin maximum principle, we apply this theory to optimal control problems
and to get results on normal and abnormal extremals. We give a
demonstration of our theory by considering the optimal control problem of one
Riemannian manifold rolling on another without twisting or slipping along
curves of minimal length.Comment: 31 page
COMPLETE CONTROLLABILITY OF THE KINEMATIC EQUATIONS DESCRIBING PURE ROLLING OF GRASSMANNIANS
This paper studies the controllability properties of certain nonholo nomic control systems, describing the rolling motion of Grassmann manifolds over
the affine tangent space at a point. The control functions correspond to the freedom of choosing the rolling curve. The nonholonomic constraints are imposed by
the non-slip and non-twist conditions on the rolling. These systems are proved to
be controllable in some submanifold of the group of isometries of the space where
the two rolling manifolds are embedded. The constructive proof of controllability
is also partially addressed.info:eu-repo/semantics/publishedVersio
The effect of lateral controls in producing motion of an airplane as computed from wind-tunnel data
This report presents the results of an analytical study of the lateral controllability of an airplane in which both the static rolling and yawing moments supplied by the controls and the reactions due to the inherent stability of the airplane have been taken into account. The investigation was undertaken partly for the purpose of coordinating the results of a long series of wind-tunnel investigations with phenomena observed in flight tests; for this reason a hypothetical average airplane, embodying the essential characteristics of both wind-tunnel models and the full-size test airplanes, was assumed for the study
Rolling Manifolds: Intrinsic Formulation and Controllability
In this paper, we consider two cases of rolling of one smooth connected
complete Riemannian manifold onto another one (\hM,\hg) of equal
dimension . The rolling problem corresponds to the situation
where there is no relative spin (or twist) of one manifold with respect to the
other one. As for the rolling problem , there is no relative spin and also
no relative slip. Since the manifolds are not assumed to be embedded into an
Euclidean space, we provide an intrinsic description of the two constraints
"without spinning" and "without slipping" in terms of the Levi-Civita
connections and \nabla^{\hg}. For that purpose, we recast the
two rolling problems within the framework of geometric control and associate to
each of them a distribution and a control system. We then investigate the
relationships between the two control systems and we address for both of them
the issue of complete controllability. For the rolling , the reachable
set (from any point) can be described exactly in terms of the holonomy groups
of and (\hM,\hg) respectively, and thus we achieve a complete
understanding of the controllability properties of the corresponding control
system. As for the rolling , the problem turns out to be more delicate. We
first provide basic global properties for the reachable set and investigate the
associated Lie bracket structure. In particular, we point out the role played
by a curvature tensor defined on the state space, that we call the
\emph{rolling curvature}. In the case where one of the manifolds is a space
form (let say (\hM,\hg)), we show that it is enough to roll along loops of
and the resulting orbits carry a structure of principal bundle which
preserves the rolling distribution. In the zero curvature case, we deduce
that the rolling is completely controllable if and only if the holonomy
group of is equal to SO(n). In the nonzero curvature case, we prove
that the structure group of the principal bundle can be realized as the
holonomy group of a connection on , that we call the rolling
connection. We also show, in the case of positive (constant) curvature, that if
the rolling connection is reducible, then admits, as Riemannian
covering, the unit sphere with the metric induced from the Euclidean metric of
. When the two manifolds are three-dimensional, we provide a complete
local characterization of the reachable sets when the two manifolds are
three-dimensional and, in particular, we identify necessary and sufficient
conditions for the existence of a non open orbit. Besides the trivial case
where the manifolds and (\hM,\hg) are (locally) isometric, we show
that (local) non controllability occurs if and only if and (\hM,\hg)
are either warped products or contact manifolds with additional restrictions
that we precisely describe. Finally, we extend the two types of rolling to the
case where the manifolds have different dimensions
Investigation of all-wheel-drive off-road vehicle dynamics augmented by visco-lock devices
A peculiarity of AWD off-road vehicles is that their behaviour depends not only on the
total power, provided by the engine, but also on its distribution among the drive
axles/wheels. In turn, this distribution is largely regulated by the drivetrain layout and its
torque distribution devices. At the output of the drivetrain system, the torque is
constrained by the interaction between the wheels and the soft soil. For off-road
automotive applications, the design of drivetrain systems has usually been largely
dominated by the mobility requirements. With the growing demand to have a multipurpose
on/off road vehicle with improved manoeuvrability over deformable soil,
particularly at higher speed, the challenges confronting vehicle designers have become
more complex.
The thesis presents a novel integrated numerical approach to assess the dynamic
behaviour of all-wheel-drive vehicles whilst operating over deformable soil terrain. [Continues.
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