Improving grasping forces during the manipulation of unknown objects

© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting /republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other worksMany of the solutions proposed for the object manipulation problem are based on the knowledge of the object features. The approach proposed in this paper intends to provide a simple geometrical approach to securely manipulate an unknown object based only on tactile and kinematic information. The tactile and kinematic data obtained during the manipulation is used to recognize the object shape (at least the local object curvature), allowing to improve the grasping forces when this information is added to the manipulation strategy. The approach has been fully implemented and tested using the Schunk Dexterous Hand (SDH2). Experimental results are shown to illustrate the efficiency of the approach.Peer ReviewedPostprint (author's final draft

Coordination of several robots based on temporal synchronization

© 2016. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/This paper proposes an approach to deal with the problem of coordinating multi-robot systems, in which each robot executes individually planned tasks in a shared workspace. The approach is a decoupled method that can coordinate the participating robots in on-line mode. The coordination is achieved through the adjustment of the time evolution of each robot along its original planned geometric path according to the movements of the other robots to assure a collision-free execution of their respective tasks. To assess the proposed approach different tests were performed in graphical simulations and real experiments.Postprint (published version

Dexterous manipulation of unknown objects using virtual contact points

The manipulation of unknown objects is a problem of special interest in robotics since it is not always possible to have exact models of the objects with which the robot interacts. This paper presents a simple strategy to manipulate unknown objects using a robotic hand equipped with tactile sensors. The hand configurations that allow the rotation of an unknown object are computed using only tactile and kinematic information, obtained during the manipulation process and reasoning about the desired and real positions of the fingertips during the manipulation. This is done taking into account that the desired positions of the fingertips are not physically reachable since they are located in the interior of the manipulated object and therefore they are virtual positions with associated virtual contact points. The proposed approach was satisfactorily validated using three fingers of an anthropomorphic robotic hand (Allegro Hand), with the original fingertips replaced by tactile sensors (WTS-FT). In the experimental validation, several everyday objects with different shapes were successfully manipulated, rotating them without the need of knowing their shape or any other physical property.Peer ReviewedPostprint (author's final draft

Efectos de reglas, modelos y consecuencias en la alimentación de niños con factores de riesgo de trastornos de conducta alimentaria.

Trabajo de investigaciónEl presente estudio identificó los efectos de las reglas, los modelos sociales y las consecuencias de reforzamiento sobre la conducta alimentaria de niños con factores de riesgo para presentar Trastornos de Conducta Alimentaria (TCA). Se definieron sólo dos parámetros de la conducta alimentaria, el primero, la cantidad de alimento ingerido medido en gramos y dos, el tipo de alimento. Los participantes fueron seleccionados de entre un grupo de 108 niños(as) siendo una selección por conveniencia de 10 niños(as) con edades de 6 a 8 años en los que se encontraron más de cinco factores de riesgo para presentar TCA, de un colegio de Bogotá, D.C.; para la inclusión de la muestra, se realizó una evaluación médica y psicológica (clínica. Se utilizó un diseño de tratamientos alternos (DTA). Se ejecutaron tres condiciones experimentales. La Fase I, se denominó Fase Pre o de evaluación de la conducta alimentaria o de línea de base. La Fase II o de aplicación de las condiciones o tratamientos, y finalmente, se realizó la fase III o fase Post, la cual consistió en evaluar la conducta alimentaria tal como se hizo en la primera Fase. Se realizó un análisis de tendencias de los niveles de preferencia y consumo del alimento ante las alternativas de alimento saludable y artificial, en relación con la presencia y ausencia de los tratamientos o condiciones (consecuencias de reforzamiento, reglas y modelos de alimentación) a lo largo de las fases experimentales evidenciando efectos clínicos y experimentales que fueran significativos y visualmente observables. Los tratamientos se evaluaron bajo el criterio terapéutico y experimental, para ello, se comparó la conducta alimentaria antes y después de los tratamientos en relación con los parámetros establecidos de elección consumo en gramos. Los resultados indicaron que la conducta alimentaria saludable presentó diferencias significativas al nivel de 0.05 bajo el criterio experimental, pero no existe información suficiente para afirmar que existe criterio terapéutico sostenido en el tiempo. Se utilizó la prueba T para muestras pequeñas en lo que se refiere a alimento saludable. Para el caso del consumo de alimento artificial o no saludable, se tuvo en cuenta que las diferencias no presentan una distribución normal y se utilizó una prueba no paramétrica como Wilcoxon. Se observó mejoría en la elección y consumo de los niños(as) ante el alimento saludable pero al mismo tiempo no se registró variación de la conducta alimentaria ante el alimento no saludable.MaestríaMagister en Psicologí

Functional anatomy of non-REM sleep

The state of non-REM sleep (NREM), or slow wave sleep, is associated with a synchronized EEG pattern in which sleep spindles and/or K complexes and high-voltage slow wave activity (SWA) can be recorded over the entire cortical surface. In humans, NREM is subdivided into stages 2 and 3–4 (presently named N3) depending on the proportions of each of these polygraphic events. NREM is necessary for normal physical and intellectual performance and behavior. An overview of the brain structures involved in NREM generation shows that the thalamus and the cerebral cortex are absolutely necessary for the most significant bioelectric and behavioral events of NREM to be expressed; other structures like the basal forebrain, anterior hypothalamus, cerebellum, caudal brain stem, spinal cord and peripheral nerves contribute to NREM regulation and modulation. In NREM stage 2, sustained hyperpolarized membrane potential levels resulting from interaction between thalamic reticular and projection neurons gives rise to spindle oscillations in the membrane potential; the initiation and termination of individual spindle sequences depends on corticothalamic activities. Cortical and thalamic mechanisms are also involved in the generation of EEG delta SWA that appears in deep stage 3–4 (N3) NREM; the cortex has classically been considered to be the structure that generates this activity, but delta oscillations can also be generated in thalamocortical neurons. NREM is probably necessary to normalize synapses to a sustainable basal condition that can ensure cellular homeostasis. Sleep homeostasis depends not only on the duration of prior wakefulness but also on its intensity, and sleep need increases when wakefulness is associated with learning. NREM seems to ensure cell homeostasis by reducing the number of synaptic connections to a basic level; based on simple energy demands, cerebral energy economizing during NREM sleep is one of the prevalent hypotheses to explain NREM homeostasis.Grant BFU2009-06991/BFI from the Spanish Ministry of Science and Innovation supported this wor

Auto-fragmentaciones : paisajes intermediales desde la auto-referencia

Es importante para el desarrollo de dichos auto-desprendimientos, entrar en un proceso de reconocimiento de los signos y estímulos que se presentan constantemente en mis obras de creación, es así como en el presente documento doy cuenta de las latencias que más reinciden y están presentes en mi obra, las cuales han sido incisivas a la hora de generar sentido a partir de las prácticas estético-artísticas; dichas latencias luego de identificadas, las estructuré de manera que fuera fácil para el lector entender la forma en que las he abordado a lo largo de mi proceso creativo. El lector encontrará desplegadas las siguientes 4 latencias, a saber: a) el estudio del paisaje, b) el uso del autorretrato, c) el componente inmersivo desde lo sonoro-visual y d) laboratorio experimental como método de investigación-creación. El estudio del paisaje lo abordo desde: el dibujo, el fragmento y como territorio recorrido e incitador de encuentros con lo sonoro. En esta primera latencia realizo reflexiones acerca de ejercicios que parten de prácticas propias del movimiento Situacionista como lo es la deriva, acciones mediante las cuales me apropio del paisaje y produzco recorridos azarosos por contextos urbanos en los que se generan encuentros con lo sonoro y trazos imaginarios, donde reflexiona partir de la obra de Francis Alys y el caminar como una práctica estética

The magnetic field configuration of a solar prominence inferred from spectropolarimetric observations in the He I 10830 A triplet

Context: The determination of the magnetic field vector in quiescent solar prominences is possible by interpreting the Hanle and Zeeman effects in spectral lines. However, observational measurements are scarce and lack high spatial resolution. Aims: To determine the magnetic field vector configuration along a quiescent solar prominence by interpreting spectropolarimetric measurements in the He I 1083.0 nm triplet obtained with the Tenerife Infrared Polarimeter installed at the German Vacuum Tower Telescope of the Observatorio del Teide. Methods. The He I 1083.0 nm triplet Stokes profiles are analyzed with an inversion code that takes into account the physics responsible of the polarization signals in this triplet. The results are put into a solar context with the help of extreme ultraviolet observations taken with the Solar Dynamic Observatory and the Solar Terrestrial Relations Observatory satellites. Results: For the most probable magnetic field vector configuration, the analysis depicts a mean field strength of 7 gauss. We do not find local variations in the field strength except that the field is, in average, lower in the prominence body than in the prominence feet, where the field strength reaches 25 gauss. The averaged magnetic field inclination with respect to the local vertical is 77 degrees. The acute angle of the magnetic field vector with the prominence main axis is 24 degrees for the sinistral chirality case and 58 degrees for the dextral chirality. These inferences are in rough agreement with previous results obtained from the analysis of data acquired with lower spatial resolutions.Comment: Accepted in A&

Planning manipulation movements of a dual-arm system considering obstacle removing

The paper deals with the problem of planning movements of two hand-arm robotic systems, considering the possibility of using the robot hands to remove potential obstacles in order to obtain a free access to grasp a desired object. The approach is based on a variation of a Probabilistic Road Map that does not rule out the samples implying collisions with removable objects but instead classifies them according to the collided obstacle(s), and allows the search of free paths with the indication of which objects must be removed from the work-space to make the path actually valid; we call it Probabilistic Road Map with Obstacles (PRMwO). The proposed system includes a task assignment system that distributes the task among the robots, using for that purpose a precedence graph built from the results of the PRMwO. The approach has been implemented for a real dual-arm robotic system, and some simulated and real running examples are presented in the paper. (C) 2014 Elsevier B.V. All rights reserved.Postprint (published version

A professional matter: an intimate way to enhance built architecture

Qüestió d'ofici pretén ser un treball que s'acosti a la professió de l'arquitecte per a conèixer millor les seves bases, la seva metodologia de treball i com el mateix desenvolupa allò que ho defineix, Arquitectura. S'indagarà en la qüestió de fer i construir arquitectura, i es veurà com aquestes dues idees es relacionen de la mà de l'arquitecte, el qual basteix ponts entre el construir i pensar el projecte. A més del plantejament d'aquest marc teòric per al quefer de l'arquitecte, s'analitzarà el com i el que es fa, idees directament relacionades amb el procés projectual, mètode que l'arquitecte segueix per a fer els plantejaments dels diversos projectes als quals es pot enfrontar. Definides aquestes idees de base i partint de les mateixes es confeccionarà una matriu d'anàlisi que aglutini una sèrie de conceptes que serveixin per a entendre millor aquest procés projectual.Cuestión de oficio pretende ser un trabajo que se acerque a la profesión del arquitecto para conocer mejor sus bases, su metodología de trabajo y como el mismo desarrolla aquello que lo define, Arquitectura. Se indagará en la cuestión de hacer y construir arquitectura, y se verá como estas dos ideas se relacionan de la mano del arquitecto, el cual tiende puentes entre el construir y pensar el proyecto. Además del planteamiento de este marco teórico para el quehacer del arquitecto, se analizará el cómo y el que se hace, ideas directamente relacionadas con el proceso proyectual, método que el arquitecto sigue para hacer los planteamientos de los diversos proyectos a los cuales se puede enfrentar. Definidas estas ideas de base y partiendo de las mismas se confeccionará una matriz de análisis que aglutine una serie de conceptos que sirvan para entender mejor este proceso proyectual.A professional matter: an intimate way to enhance built architecture” pretends to be a research project that gets close to architect profession to know better its basis, its work methodology and how it develops what defines it, architecture. It is going to go be in depth on doing and building architecture and it is going to be seen how these two ideas relations to each other from architect’s hand who links the fact of building and thinking about the project. In addition to the theoretical framework approach of the architect’s task, “how” and “what” is done will be analysed, ideas directly related to the project process which is a method that the architect uses to suggest the approaches of different projects. Once these basic ideas are defined, they will be used to generate an analysis matrix that joins several concepts that will be useful to understand better this project process