55,513 research outputs found
Robotic Ironing with 3D Perception and Force/Torque Feedback in Household Environments
As robotic systems become more popular in household environments, the
complexity of required tasks also increases. In this work we focus on a
domestic chore deemed dull by a majority of the population, the task of
ironing. The presented algorithm improves on the limited number of previous
works by joining 3D perception with force/torque sensing, with emphasis on
finding a practical solution with a feasible implementation in a domestic
setting. Our algorithm obtains a point cloud representation of the working
environment. From this point cloud, the garment is segmented and a custom
Wrinkleness Local Descriptor (WiLD) is computed to determine the location of
the present wrinkles. Using this descriptor, the most suitable ironing path is
computed and, based on it, the manipulation algorithm performs the
force-controlled ironing operation. Experiments have been performed with a
humanoid robot platform, proving that our algorithm is able to detect
successfully wrinkles present in garments and iteratively reduce the
wrinkleness using an unmodified iron.Comment: Accepted and to be published on the 2017 IEEE/RSJ International
Conference on Intelligent Robots and Systems (IROS 2017) that will be held in
Vancouver, Canada, September 24-28, 201
Rapidly convergent quasi-periodic Green functions for scattering by arrays of cylinders---including Wood anomalies
This paper presents a full-spectrum Green function methodology (which is
valid, in particular, at and around Wood-anomaly frequencies) for evaluation of
scattering by periodic arrays of cylinders of arbitrary cross section-with
application to wire gratings, particle arrays and reflectarrays and, indeed,
general arrays of conducting or dielectric bounded obstacles under both TE and
TM polarized illumination. The proposed method, which, for definiteness is
demonstrated here for arrays of perfectly conducting particles under TE
polarization, is based on use of the shifted Green-function method introduced
in the recent contribution (Bruno and Delourme, Jour. Computat. Phys. pp.
262--290 (2014)). A certain infinite term arises at Wood anomalies for the
cylinder-array problems considered here that is not present in the previous
rough-surface case. As shown in this paper, these infinite terms can be treated
via an application of ideas related to the Woodbury-Sherman-Morrison formulae.
The resulting approach, which is applicable to general arrays of obstacles even
at and around Wood-anomaly frequencies, exhibits fast convergence and high
accuracies. For example, a few hundreds of milliseconds suffice for the
proposed approach to evaluate solutions throughout the resonance region
(wavelengths comparable to the period and cylinder sizes) with full
single-precision accuracy
On the evaluation of quasi-periodic Green functions and wave-scattering at and around Rayleigh-Wood anomalies
This article presents full-spectrum, well-conditioned, Green-function methodologies for evaluation of scattering by general periodic structures, which remains applicable on a set of challenging singular configurations, usually called Rayleigh-Wood (RW) anomalies (at which the quasi-periodic Green function ceases to exist), where most existing quasi-periodic solvers break down. After reviewing a variety of existing fast-converging numerical procedures commonly used to compute the classical quasi-periodic Green-function, the present work explores the difficulties they present around RW-anomalies and introduces the concept of hybrid “spatial/spectral” representations. Such expressions allow both the modification of existing methods to obtain convergence at RW-anomalies as well as the application of a slight generalization of the Woodbury-Sherman-Morrison formulae together with a limiting procedure to bypass the singularities. (Although, for definiteness, the overall approach is applied to the scalar (acoustic) wave-scattering problem in the frequency domain, the approach can be extended in a straightforward manner to the harmonic Maxwell's and elasticity equations.) Ultimately, this thorough study of RW-anomalies yields fast and highly-accurate solvers, which are demonstrated with a variety of simulations of wave-scattering phenomena by arrays of particles, crossed impenetrable and penetrable diffraction gratings and other related structures. In particular, the methods developed in this article can be used to “upgrade” classical approaches, resulting in algorithms that are applicable throughout the spectrum, and it provides new methods for cases where previous approaches are either costly or fail altogether. In particular, it is suggested that the proposed shifted Green function approach may provide the only viable alternative for treatment of three-dimensional high-frequency configurations with either one or two directions of periodicity. A variety of computational examples are presented which demonstrate the flexibility of the overall approach
Effects of Orientations, Aspect Ratios, Pavement Materials and Vegetation Elements on Thermal Stress inside Typical Urban Canyons
The analysis of local climate conditions to test artificial urban boundaries and related climate hazards through modelling tools should become a common practice to inform public authorities about the benefits of planning alternatives. Different finishing materials and sheltering objects within urban canyons (UCs) can be tested, predicted and compared through quantitative and qualitative understanding of the relationships between the microclimatic environment and subjective thermal assessment. This process can work as support planning instrument in the early design phases as has been done in this study that aims to analyze the thermal stress within typical UCs of Bilbao (Spain) in summertime through the evaluation of Physiologically Equivalent Temperature using ENVI-met. The UCs are characterized by different orientations, height-to-width aspect ratios, pavement materials, trees’ dimensions and planting pattern. Firstly, the current situation was analyzed; secondly, the effects of asphalt and red brick stones as streets’ pavement materials were compared; thirdly, the benefits of vegetation elements were tested. The analysis demonstrated that orientation and aspect ratio strongly affect the magnitude and duration of the thermal peaks at pedestrian level; while the vegetation elements improve the thermal comfort up to two thermophysiological assessment classes. The outcomes of this study, were transferred and visualized into green planning recommendations for new and consolidated urban areas in Bilbao.The work leading to these results has received funding from COST Action TU0902, the European Community’s Seventh Framework Programme under Grant Agreement No. 308497, Project RAMSES—Reconciling Adaptation, Mitigation and Sustainable Development for Cities (2012–2017) and Diputación Foral de Bizkaia Exp. 6-12-TK-2010-0027, Project SICURB-ITS- Desarrollo de Sistemas para el análisis de la Contaminación atmosférica en zonas URBanas integrados en ITS (2010–2011)
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