http://hdl.handle.net/2117/1270 Mon, 20 May 2013 08:45:13 GMT 2013-05-20T08:45:13Z webmaster.bupc@upc.edu Universitat Politècnica de Catalunya. Servei de Biblioteques i Documentació no http://hdl.handle.net/2117/18129 Title: Modeling a coupled-inductor boost converter in the complementarity framework Authors: Carrero Candelas, Niliana Andreina; Batlle Arnau, Carles; Fossas Colet, Enric Abstract: We consider the modeling of switching circuits, consisting of passive elements, independent sources, which are subject both to externally induced switches (time events) and to state events. We focus on the use of the complementarity formalism for obtaining such hybrid (actually piecewise linear) models, assuming idealized current- voltage characteristics of the diodes and switches. In particular, a coupled-inductor Boost converter is modelled as a piece-wise complementarity system. We obtained also a discrete-time model which may be used for design and simulation purposes. In order to show the good performance of the model obtained, it is compared with the model of the converter obtained from the PSIM simulation software. Thu, 07 Mar 2013 12:59:39 GMT http://hdl.handle.net/2117/18129 2013-03-07T12:59:39Z Carrero Candelas, Niliana Andreina; Batlle Arnau, Carles; Fossas Colet, Enric no We consider the modeling of switching circuits, consisting of passive elements, independent sources, which are subject both to externally induced switches (time events) and to state events. We focus on the use of the complementarity formalism for obtaining such hybrid (actually piecewise linear) models, assuming idealized current- voltage characteristics of the diodes and switches. In particular, a coupled-inductor Boost converter is modelled as a piece-wise complementarity system. We obtained also a discrete-time model which may be used for design and simulation purposes. In order to show the good performance of the model obtained, it is compared with the model of the converter obtained from the PSIM simulation software. http://hdl.handle.net/2117/17851 Title: Búsqueda de caminos libres de colisiones para un sistema bimanual considerando la eliminación de obstáculos movibles Authors: Rodríguez Pacheco, Carlos; Montaño Sarria, Andrés Felipe; Suárez Feijóo, Raúl Abstract: Este art´ıculo aborda el problema de la planificación de movimientos de un sistema de dos manos para la sujeción un objeto con una mano utilizando la otra mano para quitar los posibles obstáculos que se encuentren en la trayectoria hacia la meta. Este enfoque se basa en Mapas de Carreteras Probabilístico (del inglés, Probabilistic Road Maps (PRM)), con la particularidad de que no se descartan las muestras en colisión con objetos movibles, sino que son clasificadas y etiquetadas de acuerdo con el obstáculo con que colisiona,y se permite la búsqueda de caminos considerando los obstáculos movibles que deben ser quitados del espacio de trabajo para obtener una ruta de acceso v´alida. El método ha sido implementado y se presentan diferentes pruebas utilizando un modelo virtual del sistema bimanual,teniendo en cuenta que uno de los robots es el que se encarga de sujetar el objeto deseado (meta) y el otro de quitar los obst´aculos encontrados. Mon, 18 Feb 2013 15:19:05 GMT http://hdl.handle.net/2117/17851 2013-02-18T15:19:05Z Rodríguez Pacheco, Carlos; Montaño Sarria, Andrés Felipe; Suárez Feijóo, Raúl no Este art´ıculo aborda el problema de la planificación de movimientos de un sistema de dos manos para la sujeción un objeto con una mano utilizando la otra mano para quitar los posibles obstáculos que se encuentren en la trayectoria hacia la meta. Este enfoque se basa en Mapas de Carreteras Probabilístico (del inglés, Probabilistic Road Maps (PRM)), con la particularidad de que no se descartan las muestras en colisión con objetos movibles, sino que son clasificadas y etiquetadas de acuerdo con el obstáculo con que colisiona,y se permite la búsqueda de caminos considerando los obstáculos movibles que deben ser quitados del espacio de trabajo para obtener una ruta de acceso v´alida. El método ha sido implementado y se presentan diferentes pruebas utilizando un modelo virtual del sistema bimanual,teniendo en cuenta que uno de los robots es el que se encarga de sujetar el objeto deseado (meta) y el otro de quitar los obst´aculos encontrados. http://hdl.handle.net/2117/17837 Title: Determining force-closure grasps reachable by a given hand Authors: Gilart, Fidel; Suárez Feijóo, Raúl Abstract: The paper presents an approach to find contact points on an object surface that are reachable by a given hand and such that the resulting grasp satisfies the force-closure condition. This is a very common problem that still requires a practical solution. The proposed method is based on the computation of a set of independent contact regions on the object boundary such that a finger contact on each region produces a force-closure grasp, and then this set of regions is iteratively recomputed while looking for a set of contact points that are reachable by a given hand. The search is done guided by a cost function that indicates the proximity of the hand fingertips to a candidate set of grasping contact points. The approach has been implemented for the Schunk Anthropomorphic Hand and planar objects,and application examples are included to illustrate its performance. Mon, 18 Feb 2013 14:30:58 GMT http://hdl.handle.net/2117/17837 2013-02-18T14:30:58Z Gilart, Fidel; Suárez Feijóo, Raúl no The paper presents an approach to find contact points on an object surface that are reachable by a given hand and such that the resulting grasp satisfies the force-closure condition. This is a very common problem that still requires a practical solution. The proposed method is based on the computation of a set of independent contact regions on the object boundary such that a finger contact on each region produces a force-closure grasp, and then this set of regions is iteratively recomputed while looking for a set of contact points that are reachable by a given hand. The search is done guided by a cost function that indicates the proximity of the hand fingertips to a candidate set of grasping contact points. The approach has been implemented for the Schunk Anthropomorphic Hand and planar objects,and application examples are included to illustrate its performance. http://hdl.handle.net/2117/17834 Title: Coordinación temporal de dos robots manipuladores Authors: Montaño Sarria, Andrés Felipe; Suárez Feijóo, Raúl Abstract: En este art´ıculo se presenta un m´etodo de coordinaci´on de movimientos en tiempo real que permite que dos robots industriales equipados con manos rob´oticas puedan ejecutar simult´aneamente tareas de manipulaci´on de objetos en una celda de trabajo compartida, evitando las posibles colisiones debidas a la planificaci´on desacoplada de los movimientos de cada robot. Para ilustrar el m´etodo propuesto se muestran experimentos en los que se asign´o a cada robot la tarea de retirar objetos de un mesa para llevarlos a una posici´on donde los puede recibir un operario. Mon, 18 Feb 2013 14:09:56 GMT http://hdl.handle.net/2117/17834 2013-02-18T14:09:56Z Montaño Sarria, Andrés Felipe; Suárez Feijóo, Raúl no En este art´ıculo se presenta un m´etodo de coordinaci´on de movimientos en tiempo real que permite que dos robots industriales equipados con manos rob´oticas puedan ejecutar simult´aneamente tareas de manipulaci´on de objetos en una celda de trabajo compartida, evitando las posibles colisiones debidas a la planificaci´on desacoplada de los movimientos de cada robot. Para ilustrar el m´etodo propuesto se muestran experimentos en los que se asign´o a cada robot la tarea de retirar objetos de un mesa para llevarlos a una posici´on donde los puede recibir un operario. http://hdl.handle.net/2117/17794 Title: Instrumento quirúrgico de sutura para anastomosis automática del tubo digestivo Authors: Tornero García, José Antonio; Suárez Feijóo, Raúl; Cano Casas, Francesc; Montaño Sarria, Andrés Felipe; López Cano, Manuel Abstract: En la cirugía digestiva, una anastomosis del intestino consiste en la reconstrucción del tubo digestivo por unión de dos cabos tras la resección de una porción del mismo. Este procedimiento, de común aplicación en diversos tipos de intervención quirúrgica se realiza actualmente mediante la aplicación de grapas metálicas debido a la complejidad inherente de la realización de una sutura manual. La automatización del proceso de sutura mediante un dispositivo diseñado a tal efecto supondría una notable mejora en el procedimiento quirúrgico asociado y posteriormente en la calidad de vida del paciente, ya que las grapas metálicas empleadas actualmente presentan diversos inconvenientes. El diseño de este dispositivo presenta gran complejidad debido al rigor de los requisitos funcionales y a la complejidad del entorno de funcionamiento así como las características de los materiales que intervienen en el proceso.En el presente trabajo se describe el desarrollo de un prototipo de dispositivo para anastomosis automática mediante sutura, evaluando su funcionalidad a nivel de laboratorio, con objeto de probar su validez Fri, 15 Feb 2013 13:50:44 GMT http://hdl.handle.net/2117/17794 2013-02-15T13:50:44Z Tornero García, José Antonio; Suárez Feijóo, Raúl; Cano Casas, Francesc; Montaño Sarria, Andrés Felipe; López Cano, Manuel no En la cirugía digestiva, una anastomosis del intestino consiste en la reconstrucción del tubo digestivo por unión de dos cabos tras la resección de una porción del mismo. Este procedimiento, de común aplicación en diversos tipos de intervención quirúrgica se realiza actualmente mediante la aplicación de grapas metálicas debido a la complejidad inherente de la realización de una sutura manual. La automatización del proceso de sutura mediante un dispositivo diseñado a tal efecto supondría una notable mejora en el procedimiento quirúrgico asociado y posteriormente en la calidad de vida del paciente, ya que las grapas metálicas empleadas actualmente presentan diversos inconvenientes. El diseño de este dispositivo presenta gran complejidad debido al rigor de los requisitos funcionales y a la complejidad del entorno de funcionamiento así como las características de los materiales que intervienen en el proceso.En el presente trabajo se describe el desarrollo de un prototipo de dispositivo para anastomosis automática mediante sutura, evaluando su funcionalidad a nivel de laboratorio, con objeto de probar su validez http://hdl.handle.net/2117/16900 Title: On the synthesis of feasible and prehensile robotic grasps Authors: Rosales Gallegos, Carlos; Suárez Feijóo, Raúl; Gabiccini, Marco; Bicchi, Antonio Abstract: This work proposes a solution to the grasp synthesis problem, which consist of finding the best hand configuration to grasp a given object for a specific manipulation task while satisfying all the necessary constraints. This problem had been divided into sequential sub-problems, including contact region determination, hand inverse kinematics and force distribution, with the particular constraints of each step tackled independently. This may lead to unnecessary effort, such as when one of the problems has no solution given the output of the previous step as input. To overcome this issue, we present a kinestatic formulation of the grasp synthesis problem that introduces compliance both at the joints and the contacts. This provides a proper framework to synthesize a feasible and prehensile grasp by considering simultaneously the necessary grasping constraints, including contact reachability, object restraint, and force controllability. As a consequence, a solution of the proposed model results in a set of hand configurations that allows to execute the grasp using only a position controller. The approach is illustrated with experiments on a simple planar hand using two fingers and an anthropomorphic robotic hand using three fingers. Tue, 13 Nov 2012 07:43:53 GMT http://hdl.handle.net/2117/16900 2012-11-13T07:43:53Z Rosales Gallegos, Carlos; Suárez Feijóo, Raúl; Gabiccini, Marco; Bicchi, Antonio no manipulators robot kinematics robots paraules autor: grasping, grasp synthesis This work proposes a solution to the grasp synthesis problem, which consist of finding the best hand configuration to grasp a given object for a specific manipulation task while satisfying all the necessary constraints. This problem had been divided into sequential sub-problems, including contact region determination, hand inverse kinematics and force distribution, with the particular constraints of each step tackled independently. This may lead to unnecessary effort, such as when one of the problems has no solution given the output of the previous step as input. To overcome this issue, we present a kinestatic formulation of the grasp synthesis problem that introduces compliance both at the joints and the contacts. This provides a proper framework to synthesize a feasible and prehensile grasp by considering simultaneously the necessary grasping constraints, including contact reachability, object restraint, and force controllability. As a consequence, a solution of the proposed model results in a set of hand configurations that allows to execute the grasp using only a position controller. The approach is illustrated with experiments on a simple planar hand using two fingers and an anthropomorphic robotic hand using three fingers. http://hdl.handle.net/2117/16186 Title: Nonlinear control and geometric constraint enforcement for teleoperated task execution Authors: Rodríguez Tsouroukdissian, Adolfo; Nuño Ortega, Emmanuel; Palomo Avellaneda, Leopoldo; Basañez Villaluenga, Luis Abstract: This work presents a multimodal teleoperation framework that makes use of novel tools and techniques, such as: nonlinear teleoperators control, for ensuring position tracking in the presence of variable time-delays; relational positioning, for increasing operator performance on precise movement execution by visually and haptically displaying geometric constraints; and augmented reality, for visually combining real and virtual information in a compelling way. Experimental evidence is presented that validates the aptitude of the different components of the proposed framework. Thu, 05 Jul 2012 11:22:22 GMT http://hdl.handle.net/2117/16186 2012-07-05T11:22:22Z Rodríguez Tsouroukdissian, Adolfo; Nuño Ortega, Emmanuel; Palomo Avellaneda, Leopoldo; Basañez Villaluenga, Luis no This work presents a multimodal teleoperation framework that makes use of novel tools and techniques, such as: nonlinear teleoperators control, for ensuring position tracking in the presence of variable time-delays; relational positioning, for increasing operator performance on precise movement execution by visually and haptically displaying geometric constraints; and augmented reality, for visually combining real and virtual information in a compelling way. Experimental evidence is presented that validates the aptitude of the different components of the proposed framework. http://hdl.handle.net/2117/15023 Title: Odd-harmonic repetitive control of an active filter under varying network frequency: control design and stability analysis Authors: Olm Miras, Josep Maria; Ramos Fuentes, Germán Andrés; Costa Castelló, Ramon; Cardoner Parpal, Rafel Abstract: This work deals with the design and analysis of a controller for a shunt active power filter. The design is based on combined feedforward and feedback actions, the last using repetitive control, and aims at the obtention of a good closedloop performance in spite of the possible frequency variations that may occur in the electrical network. As these changes affect the performance of the controller, the proposal includes a compensation technique consisting of an adaptive change of the digital controller’s sampling time according to the network frequency variation. However, this implies structural changes in the closed-loop system that may destabilize the overall system. Hence, this article is also concerned with closed-loop stability of the resulting system, which is analyzed using a robust control approach through the small gain theorem. Experimental results that indicate good performance of the closed-loop system are provided. Wed, 08 Feb 2012 14:10:00 GMT http://hdl.handle.net/2117/15023 2012-02-08T14:10:00Z Olm Miras, Josep Maria; Ramos Fuentes, Germán Andrés; Costa Castelló, Ramon; Cardoner Parpal, Rafel no This work deals with the design and analysis of a controller for a shunt active power filter. The design is based on combined feedforward and feedback actions, the last using repetitive control, and aims at the obtention of a good closedloop performance in spite of the possible frequency variations that may occur in the electrical network. As these changes affect the performance of the controller, the proposal includes a compensation technique consisting of an adaptive change of the digital controller’s sampling time according to the network frequency variation. However, this implies structural changes in the closed-loop system that may destabilize the overall system. Hence, this article is also concerned with closed-loop stability of the resulting system, which is analyzed using a robust control approach through the small gain theorem. Experimental results that indicate good performance of the closed-loop system are provided. http://hdl.handle.net/2117/14911 Title: A framework for robotized teleoperated tasks Authors: Basañez Villaluenga, Luis; Rosell Gratacòs, Jan; Palomo Avellaneda, Leopoldo; Nuño Ortega, Emmanuel; Portilla Rodríguez, Henry Abstract: Teleoperation systems allow the extension of the human operator’s sensing and manipulative capability into a remote environment to perform tasks at a distance, but the time-delays in the communications affect the stability and transparency of such systems. This work presents a teleoperation framework in which some novel tools, such as nonlinear controllers, relational positioning techniques, haptic guiding and augmented reality, are used to increase the sensation of immersion of the human operator in the remote site. Experimental evidence supports the advantages of the proposed framework. Description: "Premio al mejor artículo presentado en ROBOT 2011" atorgat pel Grupo de Robótica, Visión y Control de la Universidad de Sevilla, la Universidad Pablo Olavide i el Centro Avanzado de Tecnologías Aeroespaciales. Wed, 01 Feb 2012 12:54:31 GMT http://hdl.handle.net/2117/14911 2012-02-01T12:54:31Z Basañez Villaluenga, Luis; Rosell Gratacòs, Jan; Palomo Avellaneda, Leopoldo; Nuño Ortega, Emmanuel; Portilla Rodríguez, Henry no Teleoperation systems allow the extension of the human operator’s sensing and manipulative capability into a remote environment to perform tasks at a distance, but the time-delays in the communications affect the stability and transparency of such systems. This work presents a teleoperation framework in which some novel tools, such as nonlinear controllers, relational positioning techniques, haptic guiding and augmented reality, are used to increase the sensation of immersion of the human operator in the remote site. Experimental evidence supports the advantages of the proposed framework. http://hdl.handle.net/2117/14517 Title: Planificación de movimientos para conjuntos mano-brazo con numerosos grados de libertad Authors: Suárez Feijóo, Raúl; Rosell Gratacòs, Jan Abstract: Con el objetivo de avanzar hacia la emulaci ´on de las capacidades y destreza de la mano humana se est ´an desarrollando manos rob´oticas con prestaciones muy superiores a las tradicionales pinzas usadas en la rob´otica industrial. El uso de estas manos rob´oticas conlleva asociados nuevos retos, y entre ellos est ´a el de la planificaci ´on eficiente de sus movimientos, ya que aunque algunos m´etodos de planificaci ´on tradiciones podr´ıan ser v´alidos, su aplicaci ´on pr´actica es limitada debido sobre todo al elevado n´umero de grados de libertad que tiene un sistema rob´otico que incluya una mano antropomorfa montada sobre un brazo manipulador. Este art´ıculo presenta un enfoque que permite soluciones suficientemente eficientes para ser utilizadas en la pr´actica. El enfoque propuesto est ´a basado en la reducci ´on de la dimensi ´on del espacio de b´usqueda y en la utilizaci ´on de t´ecnicas de muestreo para generar movimientos del conjunto mano-brazo en entornos con obst ´aculos que pueden imponer fuertes restricciones en la b´usqueda de movimientos sin colisi ´on, como sucede normalmente cuando la mano se acerca a un objeto para su sujeci ´on y manipulaci ´on. Los desarrollos te´oricos han sido implementados tanto en simulaci ´on como en un sistema f´ısico real, por lo que se incluyen resultados experimentales reales. Fri, 13 Jan 2012 11:24:49 GMT http://hdl.handle.net/2117/14517 2012-01-13T11:24:49Z Suárez Feijóo, Raúl; Rosell Gratacòs, Jan no Con el objetivo de avanzar hacia la emulaci ´on de las capacidades y destreza de la mano humana se est ´an desarrollando manos rob´oticas con prestaciones muy superiores a las tradicionales pinzas usadas en la rob´otica industrial. El uso de estas manos rob´oticas conlleva asociados nuevos retos, y entre ellos est ´a el de la planificaci ´on eficiente de sus movimientos, ya que aunque algunos m´etodos de planificaci ´on tradiciones podr´ıan ser v´alidos, su aplicaci ´on pr´actica es limitada debido sobre todo al elevado n´umero de grados de libertad que tiene un sistema rob´otico que incluya una mano antropomorfa montada sobre un brazo manipulador. Este art´ıculo presenta un enfoque que permite soluciones suficientemente eficientes para ser utilizadas en la pr´actica. El enfoque propuesto est ´a basado en la reducci ´on de la dimensi ´on del espacio de b´usqueda y en la utilizaci ´on de t´ecnicas de muestreo para generar movimientos del conjunto mano-brazo en entornos con obst ´aculos que pueden imponer fuertes restricciones en la b´usqueda de movimientos sin colisi ´on, como sucede normalmente cuando la mano se acerca a un objeto para su sujeci ´on y manipulaci ´on. Los desarrollos te´oricos han sido implementados tanto en simulaci ´on como en un sistema f´ısico real, por lo que se incluyen resultados experimentales reales. http://hdl.handle.net/2117/14516 Title: Teleoperación de manos antropomorfas Authors: Suárez Feijóo, Raúl; Rosell Gratacòs, Jan; Colasanto, Luca Abstract: Un escenario ideal para la teleoperaci´on de manos antropomorfas es que el operador humano pueda realizar una determinada operaci´on con sus propias manos y el sistema rob´otico teleoperado provisto de una mano antropomorfa la replique. Actualmente ya existen manos mec´anicas antropomorfas con numerosos grados de libertad y la posibilidad de dirigir sus acciones de forma remota es viable, pero, sin embargo, la imposibilidad de que la cinem´atica de la mano rob´otica sea totalmente equivalente a la de cualquier humano genera un problema significativo en el esquema de teleoperaci´on mencionado. La respuesta a c´omo se deben reproducir los movimientos de la mano humana en la mano rob´otica para que ´esta realice la misma tarea no es lo evidente que en principio pudiera parecer. En este contexto, este art´ıculo presenta dos proyecciones de movimientos de la mano humana a la mano rob´otica que tienen como fin facilitar las tareas de telemanipulaci ´on. Ambas proyecciones han sido implementadas y en el art´ıculo se incluyen ejemplos de resultados experimentales. Fri, 13 Jan 2012 11:20:37 GMT http://hdl.handle.net/2117/14516 2012-01-13T11:20:37Z Suárez Feijóo, Raúl; Rosell Gratacòs, Jan; Colasanto, Luca no Un escenario ideal para la teleoperaci´on de manos antropomorfas es que el operador humano pueda realizar una determinada operaci´on con sus propias manos y el sistema rob´otico teleoperado provisto de una mano antropomorfa la replique. Actualmente ya existen manos mec´anicas antropomorfas con numerosos grados de libertad y la posibilidad de dirigir sus acciones de forma remota es viable, pero, sin embargo, la imposibilidad de que la cinem´atica de la mano rob´otica sea totalmente equivalente a la de cualquier humano genera un problema significativo en el esquema de teleoperaci´on mencionado. La respuesta a c´omo se deben reproducir los movimientos de la mano humana en la mano rob´otica para que ´esta realice la misma tarea no es lo evidente que en principio pudiera parecer. En este contexto, este art´ıculo presenta dos proyecciones de movimientos de la mano humana a la mano rob´otica que tienen como fin facilitar las tareas de telemanipulaci ´on. Ambas proyecciones han sido implementadas y en el art´ıculo se incluyen ejemplos de resultados experimentales. http://hdl.handle.net/2117/14504 Title: Influence of Contact Types and Uncertainties in the Computation of Independent Contact Regions Authors: Suárez Feijóo, Raúl; Roa Garzón, Máximo Abstract: Independent Contact Regions provide robustness in front of finger positioning errors during an object grasping. However, different sources of uncertainty may be present like, for instance, the friction model used in grasp planning, indetermination of the friction coefficients, and errors in the model of the object that affect the positions of the boundary points as well as the direction normal to the object surface. These sources have not been previously considered in the computation of the Independent Contact Regions. This paper discusses how to take into account these factors when computing the Independent Contact Regions for discretized objects, i.e. objects described with a cloud or a mesh of points. The considerations provided allow a more robust result for application in grasp synthesis and regrasp planning. Fri, 13 Jan 2012 09:26:06 GMT http://hdl.handle.net/2117/14504 2012-01-13T09:26:06Z Suárez Feijóo, Raúl; Roa Garzón, Máximo no Independent Contact Regions provide robustness in front of finger positioning errors during an object grasping. However, different sources of uncertainty may be present like, for instance, the friction model used in grasp planning, indetermination of the friction coefficients, and errors in the model of the object that affect the positions of the boundary points as well as the direction normal to the object surface. These sources have not been previously considered in the computation of the Independent Contact Regions. This paper discusses how to take into account these factors when computing the Independent Contact Regions for discretized objects, i.e. objects described with a cloud or a mesh of points. The considerations provided allow a more robust result for application in grasp synthesis and regrasp planning. http://hdl.handle.net/2117/14503 Title: Efficient and practical determination of grasping con gurations for anthropomorphic hands Authors: Claret, Josep Arnau; Suárez Feijóo, Raúl Abstract: The paper presents a methodology to rapidly solve the inverse kinematics of anthropomorphic hands, which is particularized for a mechanical hand considering 27 degrees of freedom. Given the contact points and normal directions on an object surface, the proposed algorithm nds the joint values and the wrist position and orientation that make the ngertips satisfy the contact constraints. The approach combines an iterative algorithm with an o - line analysis that allows signi cant reductions of the execution time. The approach has been implemented and the paper includes application examples. The e ectiveness and fast execution of the algorithm is demonstrated with statistical results. Fri, 13 Jan 2012 09:17:46 GMT http://hdl.handle.net/2117/14503 2012-01-13T09:17:46Z Claret, Josep Arnau; Suárez Feijóo, Raúl no The paper presents a methodology to rapidly solve the inverse kinematics of anthropomorphic hands, which is particularized for a mechanical hand considering 27 degrees of freedom. Given the contact points and normal directions on an object surface, the proposed algorithm nds the joint values and the wrist position and orientation that make the ngertips satisfy the contact constraints. The approach combines an iterative algorithm with an o - line analysis that allows signi cant reductions of the execution time. The approach has been implemented and the paper includes application examples. The e ectiveness and fast execution of the algorithm is demonstrated with statistical results. http://hdl.handle.net/2117/14118 Title: Global optimization of robotic grasps Authors: Rosales Gallegos, Carlos; Porta Pleite, Josep Maria; Ros Giralt, Lluís Abstract: This paper presents a procedure to optimize the quality of robotic grasps for objects that need to be held and manipulated in a specific way, characterized by a number of tight contact constraints. The main difficulties of the problem include that the set of feasible grasps is a manifold implicitly defined by a system of non-linear equations, the high dimension of this manifold, and the multi-modal nature of typical grasp quality indices, which make local optimization methods get trapped into local extrema. The proposed procedure finds a way around these difficulties by focussing the exploration on a relevant subset of grasps of lower dimension, which is traced out exhaustively using higher-dimensional continuation techniques. Using these techniques, a detailed atlas of the subset is obtained, on which the highest quality grasp according to any desired criterion can be readily identified. Experiments on a 3-finger planar hand and on the Schunk anthropomorphic hand validate the approach. Wed, 30 Nov 2011 12:26:09 GMT http://hdl.handle.net/2117/14118 2011-11-30T12:26:09Z Rosales Gallegos, Carlos; Porta Pleite, Josep Maria; Ros Giralt, Lluís no robot kinematics PARAULES AUTOR: grasping This paper presents a procedure to optimize the quality of robotic grasps for objects that need to be held and manipulated in a specific way, characterized by a number of tight contact constraints. The main difficulties of the problem include that the set of feasible grasps is a manifold implicitly defined by a system of non-linear equations, the high dimension of this manifold, and the multi-modal nature of typical grasp quality indices, which make local optimization methods get trapped into local extrema. The proposed procedure finds a way around these difficulties by focussing the exploration on a relevant subset of grasps of lower dimension, which is traced out exhaustively using higher-dimensional continuation techniques. Using these techniques, a detailed atlas of the subset is obtained, on which the highest quality grasp according to any desired criterion can be readily identified. Experiments on a 3-finger planar hand and on the Schunk anthropomorphic hand validate the approach. http://hdl.handle.net/2117/12782 Title: Importance Sampling based on Adaptive Principal Component Analysis Authors: Rosell Gratacòs, Jan; Cruz Llopis, Luis Javier de la; Pérez, Alexander; Suárez Feijóo, Raúl Abstract: Sampling-based approaches are currently the most efficient ones to solve path planning problems, being their performance dependant on the ability to generate samples in those areas of the configuration space relevant to the problem. This paper introduces a novel importance sampling method that uses Principal Component Analysis to focalize the region where to sample in order to increase the probability of finding collision-free configurations. The proposal is illustrated with a 2D configuration space with a narrow passage and compared to the uniform random sampling method. Wed, 15 Jun 2011 17:11:39 GMT http://hdl.handle.net/2117/12782 2011-06-15T17:11:39Z Rosell Gratacòs, Jan; Cruz Llopis, Luis Javier de la; Pérez, Alexander; Suárez Feijóo, Raúl no Sampling-based approaches are currently the most efficient ones to solve path planning problems, being their performance dependant on the ability to generate samples in those areas of the configuration space relevant to the problem. This paper introduces a novel importance sampling method that uses Principal Component Analysis to focalize the region where to sample in order to increase the probability of finding collision-free configurations. The proposal is illustrated with a 2D configuration space with a narrow passage and compared to the uniform random sampling method.