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

Lignin-based coatings for controlled release fertilizers by coating single superphosphate

FI.Tesis de Maestría. Reporte Técnico 326Pulp mills generate dissolved lignin as a by-product, which is currently burnt to produce steam and electric energy. In recent years, the price of electric energy in Uruguay has reduced as a consequence of the installation of wind farms. As a result there is a greater interest in finding more valuable applications for lignin, thus improving the efficiency of the forest value chain. In this master's thesis work single-superphosphate fertilizer was coated using lignin as the main material of the film. In this way coated controlled release fertilizers (CRF) were prepared, controlling the diffusion of phosphorus through the film. The objective of this work was to study different lignin-based coatings and the phosphorus release behaviour of the resulting fertilizer. Lignin was chemically modified to be incorporated into the coating solution. Two different groups of coating materials were prepared: 1) thermoset resin composed of hydroxymethylated lignin and phenol-formaldehyde (PF) resin, with talc as a filler; and 2) thermoplastic blend of acetylated lignin and cellulose acetate. In the first material aqueous sodium hydroxyde solution was used as a solvent, while the second was dissolved in acetone. During lignin modification several experimental conditions were tested in order to improve the resulting material. The fertilizers were submerged in water and their phosphorus fractional release curve was determined. Its behaviour adjusted well to the diffusion mechanism proposed by Shaviv et al. (2003). All tested coatings had similar phosphorus permeability values and no significant difference was found between the two groups of lignin-based materials. However, the release behaviour departs from the model during the decaying phase, because the release rate reduced long before most of the fertilizer had been released. These findings were atributed to the presence of calcium sulphate, which low solubility and slow release indirectly limit calcium phosphate monobasic dissolution. In this way the phosphorus ocluded inside the calcium sulphate matrix would not be released.La industria de procesamiento de la celulosa genera lignina, la cual se utiliza como combustible para producir vapor y energía eléctrica. En los últimos años el precio de la energía eléctrica que obtienen los generadores se ha reducido como consecuencia de la instalación de parques eólicos. En consecuencia resulta de interés encontrar aplicaciones de mayor valor agregado para la lignina, mejorando así la eficiencia de la cadena forestal. El fertilizante superfosfato de calcio fue recubierto utilizando recubrimientos con lignina como material principal. De esta manera se prepararon fertilizantes de liberación controlada. El objetivo de este trabajo fue estudiar diferentes recubrimientos en base a lignina y el comportamiento del fertilizante recubierto al ser sumergido en agua. En la parte experimental de esta tesis la lignina fue modificada químicamente para ser incorporada eficazmente en el recubrimiento. Se ensayó con dos clases distintas de recubrimiento: 1) una resina compuesta de lignina hidroximetilada y resina fenol-formaldehído, con talco como relleno; y 2) material termoplástico compuesto de lignina acetilada y acetato de celulosa. En todos los casos se ensayaron diferentes condiciones de reacción para modificar la lignina y se seleccionó la mejor condición para preparar el recubrimiento.Los fertilizantes fueron ensayados en agua y se hizo un seguimiento de la curva de liberación de fósforo. Su comportamiento se adecuó al modelo de difusión propuesto por Shaviv et al. (2003). Todos los fertilizantes ensayados mostraron semejante magnitud en su permeabilidad al fósforo. Sin embargo, el comportamiento se alejó del modelo durante la etapa final de la liberación, porque ésta comenzó mucho antes de la que la mayor parte del fósforo hubiera sido liberado. Se atribuye este fenómeno a la presencia de sulfato de calcio, cuya baja solubilidad y lenta liberación limita indirectamente la disolución del fosfato monocálcico. De esta manera el fosfato ocluído dentro del sulfato de calcio no sería liberado

Identificación del modelo de desarrollo económico del municipio de Bello

En la actualidades necesario utilizar el más poderoso recurso que es el conocimiento, para lograr, junto con los demás recursos y capacidades, las competencias centrales y propuestas de valor que les permitan, al gobierno público dirigir sus esfuerzos a fortalecer su vocación económica, al tiempo que, a las empresas, tener oportunidades de inversión que dinamicen a su vez la economía local -- El aprovechamiento de las oportunidades depende de la estrategia, y esta, a su vez, depende de la estructura asignada por los gobiernos y las empresas para aprovechar lo que ofrecen las realidades de cada localidad -- Con base en lo anterior, se propone identificar las fortalezas de Bello por medio de la identificación de su modelo de desarrollo, que sirva como insumo de planificación, organización, verificación y control -- Finalmente, después de la identificación se determinan dos líneas estratégicas como propuesta al modelo de desarrollo según la base económica del municipio, las cuales son: el fortalecimiento del sector agropecuario y el fortalecimiento del sector servicio

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

Solución de Dos Estudios de Caso Bajo el uso de Tecnología CISCO

A continuación, se presentarán los procesos de documentación a la solución, registros de configuración de cada uno de los dispositivos, información detallada del registro de verificación de conectividad mediante el uso de comandos ping, show ip rout, entre otros, con el fin de dar solución al desarrollo del diplomado de profundización Cisco (diseño e implementación de soluciones integradas LAN/WAN). Su finalidad es buscar que como futuro profesional en la rama se obtengan conocimientos y experiencias aplicando soluciones de estudios de caso bajo el uso de tecnología Cisco usando el software de simulación Cisco Packet Tracer. Lo principal es poner a prueba los niveles de comprensión y solución de problemas relacionados con diversos aspectos de networking.Next, the documentation processes will be presented to the solution, configuration records of each of the devices, detailed information of the connectivity verification record through the use of ping commands, show ip routing, among others in order to provide a solution to the development of the Cisco deepening diploma (design and implementation of integrated LAN / WAN solutions). Its purpose is to ensure that as a future professional in the field, knowledge and experiences are obtained by applying case study solutions using Cisco technology using Cisco Packet Tracer simulation software. The main thing is to test the levels of understanding and problem solving related to various aspects of networking

Detection of emission in the Si i 1082.7 nm line core in sunspot umbrae

We analyze spectropolarimetric sunspot umbra observations taken in the near-infrared Si i 1082.7 nm line taking NLTE effects into account. The data were obtained with the GRIS instrument installed at the German GREGOR telescope. A point spread function (PSF) was constructed using prior Mercury observations with GRIS and the information provided by the adaptive optics system of the GREGOR telescope. The data were then deconvolved from the PSF using a principal component analysis deconvolution method and were analyzed via the NICOLE inversion code. The Si i 1082.7 nm line seems to be in emission in the umbra of the observed sunspot after the effects of scattered light are removed. We show how the spectral line shape of umbral profiles changes dramatically with the amount of scattered light. Indeed, the continuum levels range, on average, from 44% of the quiet Sun continuum intensity to about 20%. The inferred levels are in line with current model predictions and empirical umbral models. Current umbral empirical models are not able to reproduce the emission in the deconvolved umbral Stokes profiles. The results of the NLTE inversions suggests that to obtain the emission in the Si i 1082.7 nm line, the temperature stratification should first have a hump located at about log tau -2 and start rising at lower heights when moving into the transition region. This is, to our knowledge, the first time the Si i 1082.7 nm line is seen in emission in sunspot umbrae. The results show that the temperature stratification of current umbral models may be more complex than expected with the transition region located at lower heights above sunspot umbrae. Our finding might provide insights into understanding why the sunspot umbra emission in the millimeter spectral range is less than that predicted by current empirical umbral models

A collaborative company commited to ethics and labor conditions

Estudia2 es un proyecto empresarial joven y colaborativo, con menos de cinco años de andadura, que ha nacido con la intención de ser una plataforma internacional de encuentro entre personas para compartir conocimientos, una plataforma de E-learning llevada a cabo con la conjunción de un diseño propio y el empleo de una serie de herramientas TIC de acceso libre. Una de las máximas más importantes con las que ha nacido esta empresa es el respeto absoluto por unos valores éticos basados en el cumplimiento de las condiciones laborales de los trabajadores, los derechos de autoría de los creadores de contenidos y la privacidad de los datos de los usuarios.Estudia2 is a young and collaborative business project, with less than five years operating, that was born with the goal of being an international platform for connecting people to share knowledge. An E-learning platform developed with the conjunction of an own design and the use of a mixture of free access ICT tools. One of the most important ideas which this project has been born in, is the absolute respect to several ethical values based on the fulfillment of the workers’ labor conditions, the intellectual property rights of the content creators and the privacy of the user data.Ministerio de Economía y Competitividad CSO2016-78386-