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  • A three-stage method for the 3D reconstruction of the tracheobronchial tree from CT scans

     Rosell Gratacos, Joan; Cabras, Paolo
    Computerized medical imaging and graphics
    Date of publication: 2013-10
    Journal article

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    This paper proposes a method for segmenting the airways from CT scans of the chest to obtain a 3D model that can be used in the virtual bronchoscopy for the exploration and the planning of paths to the lesions. The method is composed of 3 stages: a gross segmentation that reconstructs the main airway tree using adaptive region growing, a finer segmentation that identifies any potential airway region based on a 2D process that enhances bronchi walls using local information, and a final process to connect any isolated bronchus to the main airways using a morphologic reconstruction process and a path planning technique. The paper includes two examples for the evaluation and discussion of the proposal. © 2013 Elsevier Ltd.

    This paper proposes a method for segmenting the airways from CT scans of the chest to obtain a 3D modelthat can be used in the virtual bronchoscopy for the exploration and the planning of paths to the lesions.The method is composed of 3 stages: a gross segmentation that reconstructs the main airway tree usingadaptive region growing, a finer segmentation that identifies any potential airway region based on a 2Dprocess that enhances bronchi walls using local information, and a final process to connect any isolatedbronchus to the main airways using a morphologic reconstruction process and a path planning technique.The paper includes two examples for the evaluation and discussion of the proposal.

  • Hybrid mapping for the assistance of teleoperated grasping tasks

     Colasanto, Luca; Suarez Feijoo, Raul; Rosell Gratacos, Joan
    IEEE transactions on systems man and cybernetics Part A-systems and humans
    Date of publication: 2013-09-12
    Journal article

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    Teleoperating a robotic hand with the aid of a sensorized glove presents some particular problems. A certain problem is due to the kinematic differences between the human hand and the robotic hand, which do not allow a simple direct mapping of the sensor readings from the glove to the robotic hand. This problem is addressed with different types of mapping, but none of them is of general use. This paper proposes two new mappings within two existing mapping types, as well as a new hybrid mapping that combines the best features of these existing mapping types. This hybrid mapping allows intuitive free space movements (where the gesture is more important than the precise positions of the fingers) and grasp movements (where the precise positions of the fingers is more important than the gesture), despite kinematic differences between the human hand and the robotic hand. The approach has been implemented, and some illustrative examples are presented in this paper.

  • Path planning for grasping operations using an adaptive PCA-based sampling method

     Rosell Gratacos, Joan; Suarez Feijoo, Raul; Perez Ruiz, Alexander
    Autonomous robots
    Date of publication: 2013-07-01
    Journal article

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    The planning of collision-free paths for a handarm robotic system is a difficult issue due to the large number of degrees of freedom involved and the cluttered environment usually encountered near grasping configurations. To cope with this problem, this paper presents a novel importance sampling method based on the use of principal component analysis (PCA) to enlarge the probability of finding collisionfree samples in these difficult regions of the configuration space with low clearance. By using collision-free samples near the goal, PCA is periodically applied in order to obtain a sampling volume near the goal that better covers the free space, improving the efficiency of sampling-based path planning methods. The approach has been tested with success on a hand-arm robotic system composed of a four-finger anthropomorphic mechanical hand (17 joints with 13 independent degrees of freedom) and an industrial robot (6 independent degrees of freedom).

  • Haptic aids for bilateral teleoperators

     Pérez Ruiz, Alexander; Rosell Gratacos, Joan
    Iberian Robotics Conference
    Presentation's date: 2013-11-28
    Presentation of work at congresses

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    Teleoperation of robotic tasks is usually performed in the Cartesian space due to the kinematic differences between the master and the slave. This entails several requirements, like the definition of a proper mapping between workspaces, the need to avoid collisions of the teleoperated robot with the environment, and the use of the inverse kinematics and of a procedure to correctly manage the passing through singularities. Within a bilateral teleoperation framework to teleoperate an industrial robot with a desktop haptic device, the present work proposes a guiding system based on path planning techniques to cope with these issues. The proposed system also includes a reactive behavior to cope with the potential collisions with obstacles. Teleoperation tests on virtual and real scenarios are included to validate the approach.

    Teleoperation of robotic tasks is usually performed in the Cartesian space due to the kinematic differences between the master and the slave. This entails several requirements, like the definition of a proper mapping between workspaces, the need to avoid collisions of the teleoperated robot with the environment, and the use of the inverse kinematics and of a procedure to correctly manage the passing through singularities. Within a bilateral teleoperation framework to teleoperate an industrial robot with a desktop haptic device, the present work proposes a guiding system based on path planning techniques to cope with these issues. The proposed system also includes a reactive behavior to cope with the potential collisions with obstacles. Teleoperation tests on virtual and real scenarios are included to validate the approach.

  • Safe teleoperation of a dual hand-arm robotic system

     Rosell Gratacos, Joan; Suarez Feijoo, Raul; Pérez Ruiz, Alexander
    Iberian Robotics Conference
    Presentation's date: 2013-11-28
    Presentation of work at congresses

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    This paper introduces a supervised teleoperation system to cope with some of the main problems that arise in the teleoperation of hand-arm robotic systems. The set-up consists of two magnetic trackers and two sensorized gloves that command, respectively, two industrial robots and the mechanical hands with which they are equipped. The basic mapping aspects both at hand and arm level are discussed, as well as the communication issues related with the implementation done based on ROS (Robot Operating System). The risk of collisions and of reaching singular configurations, either internal or due to the workspace limits, is controlled by monitoring the state of the hand-arm system and stoping it when necessary. An automatic re-synchronization procedure allows to resume the teleoperation as soon as the risk has disappeared, and also permits the user to change the mapping when his/her posture becomes uncomfortable. The resulting system allows an intuitive, simple and safe teleoperation of a dual hand-arm robotic system.

  • Using path planning techniques to improve airway tree segmentation from CT images

     Cabras, Paolo; Rosell Gratacos, Joan
    International Conference on Bio-inspired Systems and signal Processing
    Presentation's date: 2013-02-13
    Presentation of work at congresses

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    Virtual Bronchoscopy (VB) permits the preplanning of operations concerning the airways and provides the necessary guidance to reach the pulmonary lesions. Fundamental for a good VB is the reconstruction of a 3D model of the airways from the CT images. Airway segmentation algorithms usually return the biggest detected volume connected to the trachea (the root tree), but many of them also reconstruct during the segmentation process, small parts not connected to the root tree. To overcome this problem this paper proposes a method, based on path planning techniques, that is able to connect the small isolated pieces of bronchi to the terminal points of the root airway tree, taking into account the growing direction of the branches and the gray values of the CT images. As a result, a more complete 3D model of the airways is obtained.

  • Haptic guidance using primitives for the execution of virtual robotic tasks

     Vázquez Hurtado, Carlos; Rosell Gratacos, Joan
    IEEE Electronics, Robotics and Automotive Mechanics Conference
    Presentation's date: 2012-11-20
    Presentation of work at congresses

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    Haptic guidance is a powerful tool for people rehabilitation, for handcraft skills acquisition and all kind of enactive tasks. In this paper, different techniques to achieve reliable haptic feedback on the execution of virtual robotic tasks, based on the efficient combination of path planning methods and haptic guidance primitives, are presented. Abstract The main contribution of this paper is a reliable system of force guidance based on haptic primitives. The whole proposal is constituted by: 1) a free collision path obtained using a deterministic sampling, hierarchical cell decomposition and harmonic functions 2) force feedback, achieved by means of elastic models, based on simple geometry elements, called haptic primitives, and 3) a virtual robotic task.

    Haptic guidance is a powerful tool for people rehabilitation, for handcraft skills acquisition and all kind of enactive tasks. In this paper, different techniques to achieve reliable haptic feedback on the execution of virtual robotic tasks, based on the efficient combination of path planning methods and haptic guidance primitives, are presented. The main contribution of this paper is a reliable system of force guidance based on haptic primitives. The whole proposal is constituted by: 1) a free collision path obtained using a deterministic sampling, hierarchical cell decomposition and harmonic functions 2) force feedback, achieved by means of elastic models, based on simple geometry elements,called haptic primitives, and 3) a virtual robotic task.

  • Motion planning for the virtual bronchoscopy

     Rosell Gratacos, Joan; Perez Ruiz, Alexander; Cabras, Paolo; Rosell, Antoni
    IEEE International Conference on Robotics and Automation
    Presentation's date: 2012-05-16
    Presentation of work at congresses

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    Bronchoscopy is an interventional medical procedure employed to analyze the interior side of the human airways, clear possible obstructions and biopsy. Using a 3D reconstruction of the tracheobronchial tree, Virtual Bronchoscopy (VB) may help physicians in the exploration of peripheral lung lesions. We are developing a haptic-based navigation system for the VB that allows the navigation within the airways using a haptic device whose permitted motions mimics those done with the real bronchoscope. This paper describes the motion planning module of the system devoted to plan a path from the trachea to small peripheral pulmonary lesions, that takes into account the geometry and the kinematic constraints of the bronchoscope. The motion planner output is used to visually and haptically guide the navigation during the virtual exploration using the haptic device. Moreover, physicians can get useful information of whether the peripheral lesions can effectively be reached with a given bronchoscope or of which is the nearest point to the lesion that can be reached.

  • Procedimiento de generación de un recorrido para una broncoscopia virtual

     Rosell Gratacos, Joan; Perez Ruiz, Alexander; Cabras, Paolo; Rosell Gratacos, Antoni
    Date of request: 2012-05-14
    Invention patent

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    Procedimiento y sistema de generación de un recorrido para una broncoscopia virtual, que comprende generar un modelo de un árbol traqueo-bronquial y un modelo de un broncoscopio. El modelo del árbol traqueo-bronquial comprende una representación de las paredes del árbol y de una zona objetivo. El modelo del broncoscopio comprende una representación de un extremo visor (punta) del broncoscopio mediante una cadena cinemática de cuerpos rígidos articulados entre sí. Los cuerpos rígidos comprenden al menos una base y un cuerpo visor. La rotación de las articulaciones representa un movimiento de flexión de la punta. El procedimiento comprende además calcular una secuencia de desplazamientos de la cadena que conduzca el cuerpo visor hacia el objetivo sin que ninguno de los cuerpos rígidos sobrepase las paredes del árbol traqueo-bronquial, siendo calculado cada tramo aplicando al menos un valor de rotación de las articulaciones de la cadena y un movimiento de avance de la cadena.

  • Procedimiento y sistema de generación de un recorrido para una broncoscopia virtual

     Rosell Gratacos, Joan; Cabras, Paolo; Perez Ruiz, Alexander; Rosell Gratacòs, Antoni
    Date of request: 2012-05-14
    Invention patent

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  • Sincronización y teleoperación con interacción visual 3D de redes de manipuladores móviles y robots con articulaciones flexibles

     Mas Casals, Orestes Miquel; Rosell Gratacos, Joan; Nuño Ortega, Emmanuel; Palomo Avellaneda, Leopold; Flores Bazaldua, Ignacio; Beltran Guerrero, Diana Marcela; Perez Ruiz, Alexander; Basañez Villaluenga, Luis
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  • Asistencia háptica basada en planificación de movimientos para la teleoperación cooperativa de sistemas multirobot  Open access

     Perez Ruiz, Alexander
    Defense's date: 2012-10-17
    Institute of Industrial and Control Engineering (IOC), Universitat Politècnica de Catalunya
    Theses

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    This work proposes a framework for the teleoperation of anthropomorphic industrial robots using desktop haptic devices that provides an aid to the operator in the form of haptic guidance based on path planning techniques. The teleoperation framework incorporates a new model of correspondence mapping between the workspace of the haptic device used to command the remote node and that of the robot. The mapping takes into account the position and orientation of the active camera that provides the video fed back from the remote node. The main features of this system are: 1. The user can change the position of the active camera to increase the visibility or to change the scales related to the workspaces in order to set the precision. 2. The user feels slight guiding forces that attract and push him/her to the path towards the goal configuration, particularly when it contains configuration changes. 3. When the operator requests it or when he/she reaches the limits of the workspace of the haptic device, the assistance system calculates the new configuration for the haptic device, taking over the teleoperation and guiding the operator to that configuration where teleoperation can resume. All kinesthetic aids are generated based on a Planner which includes a novel algorithm that is able to find feasible paths between both static and mobile obtacles or a mitxture of both. The main features of the proposed Planner are: 1. It is based on a Probabilistic RoadMap strategy based on a lazy evaluation of the possible collisions of the path. 2. It uses a reduced graph to find the solution path, which is a subset of a larger graph, thus ensuring both computational efficiency and coverage of the whole configuration space. 3. Each planned path is evaluated and iteratively improved by creating a new set of samples closer to the obstacles when any edge-validation fails. 4. Replanning is useful when moving obstacles are present or when the initial configuration changes and this process always brings as a result a new path very close to the one previously valid. The Planner frees the user from paying attention to potential collisions between the environment and any part of the robot (not only the end-effector, as other approaches do). This can be applied especially in multi-robot environments, where the other robots present in the cell may interfere with the remote teleoperated movements. The planner deals with other robots as collections of moving obstacles. The bilateral control scheme of the teleoperation system ensures its stability despite time delays. Additionally, the system influences on the remote node damping factor as a way of dealing with potential collisions, slowing the teleoperation when the system detects one. The system has been validated with multiple users, both in simulated environments and with the real robot, and it has shown that with the use of its assistance the operator increases speed and security in performance, lightening the burden of teleoperation, especially when there are moving obstacles.

    En el presente trabajo se propone un marco para la teleoperación de robots industriales antropomórficos que cuenta con elementos de ayuda al operador en forma de guiado háptico basado en técnicas de planificación de caminos (path planning) para facilitarle su labor. Incorpora un novedoso modelo de correspondencia entre el espacio de trabajo del dispositivo háptico con el que va a ser comandado y el del robot. Esta correspondencia tiene en cuenta la posición y orientación de la cámara activa que proporciona el video desde el sitio remoto. Las principales características de este sistema son: 1. El usuario puede cambiar de cámara activa para incrementar la visibilidad o cambiar las escalas que relacionan los espacios de trabajo para ajustar la precisión. 2. El usuario experimenta ligeras fuerzas de guiado que lo atraen hacia el camino planificado y también lo empujan a lo largo del mismo hacia la configuración objetivo, en particular cuando contiene cambios de configuración. 3. Cuando se alcanzan los limites del espacio de trabajo del dispositivo háptico o cuando el usuario lo solicita, se calcula la nueva configuración de este dispositivo, desde donde pueda retomar y efectuar la teleoperación y lo guía hasta ella. Las ayudas hápticas son generadas a partir de un camino que soluciona la tarea. Para lo cual se ha desarrollado un planificador que incorpora un novedoso algoritmo que es capaz de encontrar caminos realizables tanto entre obstáculos estáticos como entre móviles o la mezcla de unos y otros. Las principales características del planificador propuesto en el presente trabajo son: 1. Está basado en un planificador de mapa de carreteras probabilístico (Probabilistic Roadmap) con evaluación tardía de las colisiones del camino encontrado. 2. Se reduce la cantidad de muestras que componen el grafo donde se busca la solución a partir de uno más grande que cubre el espacio de configuraciones. 3. Cada camino planificado es evaluado y mejorado progresivamente de forma iterativa, creando un nuevo conjunto de muestras cerca de los obstáculos cuando la validación de alguna arista falla. 4. Es útil para replanificar cuando están presentes obstáculos móviles o cuando la configuración inicial cambia, dando siempre como resultado un camino muy cercano al anteriormente válido. Con esta ayuda el usuario se libera de prestar atención a las potenciales colisiones de cualquier parte del robot con el entorno y no solamente del efector final del robot (TCP) como se hace en otros enfoques. Esto es aplicado especialmente en entornos multirobot donde los otros robots presentes en la celda remota pueden interferir con los movimientos teleoperados y que en este trabajo son considerados como colecciones de obstáculos móviles. El esquema de control del sistema de teleoperación bilateral, garantiza la estabilidad a pesar de los retardos de las variables. Adicionalmente, se influye sobre su factor de amortiguamiento en el nodo remoto como una forma de hacer frente a potenciales colisiones, ralentizando la teleoperación cuando se advierte una potencial colisión. El sistema ha sido validado con varios usuarios, tanto en simulación como en experimentación con el robot real,mostrando que con esta asistencia se incrementa la velocidad y la seguridad en la ejecución de la tarea y se aligera la carga de la teleoperación, en especial cuando existen obstáculos móviles.

  • Planificación de Movimientos en Entornos Dinámicos o Inciertos Mediante la Coordinación de Métodos Aleatorios de Búsqueda y Funciones Armónicas  Open access

     Íñiguez Galvete, Pedro Jesus
    Defense's date: 2012-05-23
    Institute of Industrial and Control Engineering (IOC), Universitat Politècnica de Catalunya
    Theses

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    En los métodos planificadores de trayectorias basados en funciones potenciales, la utilización de las funciones armónicas tiene la importante propiedad de no presentar mínimos locales. Sin embargo, la creación de planificadores basados en estas funciones armónicas se ha encontrado con serias dificultades, sobre todo cuando el número de grados de libertad es elevado. Por este motivo, esta tesis realiza inicialmente un estudio de las propiedades más relevantes de dichas funciones armónicas; destacando aquellas que han sido la causa de su reducida aplicación en la generación de trayectorias. Al mismo tiempo, el resultado de este estudio sirve de base para la proposición de métodos compensatorios que permitan reducir las propiedades negativas de las funciones armónicas, como funciones potenciales aplicables a la generación de movimientos en robótica. Después se considera los métodos numéricos de cálculo de las funciones armónicas, así como el coste computacional de los mismos. Con el objetivo de reducir el tiempo de cálculo, esta tesis propone una discretización jerárquica y un método eficiente de etiquetado de celdas. Por su parte, dicha discretización jerárquica, se va realizando progresivamente mediante muestreo aleatorio y descomposición de celdas, lo que genera un escenario parcialmente conocido que, sin embargo, permitirá en cierto número de casos encontrar la trayectoria buscada. Por lo tanto, esta propuesta reduce drásticamente el número de puntos de cálculo y, por consiguiente, el tiempo de computación. La tesis completa la propuesta de un planificador combinando las técnicas de muestreo con el cálculo de funciones armónicas mediante un método de exploración aleatorio conducido (PHM), aplicado a un espacio de configuraciones discretizado jerárquicamente sobre el que se va recalculando la función armónica. De esta forma la exploración se guía hacia zonas más prometedoras, intentando obtener la solución por fases.

    In methods based trajectories planners potential functions, the use of harmonic functions has the important property of not presenting local minima. However, the creation of planners based on these harmonic functions has met with serious difficulties, especially when the number of degrees of freedom is high. For this reason, this thesis makes an initial study of the properties most relevant of these harmonic functions, highlighting those that have been the cause of their limited application in the generation of trajectories. At the same time, the result of this study provides a basis for proposing compensatory methods to reduce the negative properties of harmonic functions as potential functions applicable to the generation of robotic movements. Then we consider numerical methods for calculating the harmonic functions and the computational cost of the same. In order to reduce computation time, this thesis proposes a hierarchical discretization and an efficient method of labeling cells. Meanwhile, this discretization hierarchical be made gradually by random sampling and decomposition of cells, generating a scene partially known, however, allow a number of cases in finding the trajectory sought. Therefore, this proposal drastically reduces the number of calculation points, and hence the computation time. The thesis, complete a proposed planner combining sampling techniques to the calculation of harmonic functions by a method of random exploration conducted (PHM), applied to a hierarchically discretized configuration space on which the harmonic function is recalculated. In this way the exploration is guided to more promising, trying to obtain the solution phases.

  • Haptic guidance based on harmonic functions path planning for the teleoperation of robotic tasks

     Vázquez Hurtado, Carlos
    Defense's date: 2012-01-27
    Institute of Industrial and Control Engineering (IOC), Universitat Politècnica de Catalunya
    Theses

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  • Autonomous motion planning of a hand-arm robotic system based on captured human-like hand postures

     Rosell Gratacos, Joan; Suarez Feijoo, Raul; Rosales Gallegos, Carlos; Perez Ruiz, Alexander
    Autonomous robots
    Date of publication: 2011-07
    Journal article

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    The paper deals with the problem of motion planning of anthropomorphic mechanical hands avoiding collisions and trying to mimic real human hand postures. The approach uses the concept of “principal motion directions” to reduce the dimension of the search space in order to obtain results with a compromise between motion optimality and planning complexity (time). Basically, the work includes the following phases: capturing the human hand workspace using a sensorized glove and mapping it to the mechanical hand workspace, reducing the space dimension by looking for the most relevant principal motion directions, and planning the hand movements using a probabilistic roadmap planner. The approach has been implemented for a four finger anthropomorphic mechanical hand (17 joints with 13 independent degrees of freedom) assembled on an industrial robot (6 independent degrees of freedom), and experimental examples are included to illustrate its validity.

  • Importance Sampling based on Adaptive Principal Component Analysis

     Rosell Gratacos, Joan; Cruz, Luis; Perez Ruiz, Alexander; Suarez Feijoo, Raul
    IEEE International Symposium on Assembly and Manufacturing
    Presentation's date: 2011-05
    Presentation of work at congresses

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    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.

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    A framework for robotized teleoperated tasks  Open access  awarded activity

     Basañez Villaluenga, Luis; Rosell Gratacos, Joan; Palomo Avellaneda, Leopold; Nuño, Emmanuel; Portilla, Henry
    Workshop Español de Robótica
    Presentation's date: 2011-11-28
    Presentation of work at congresses

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    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.

    "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.

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    Planificación de movimientos para conjuntos mano-brazo con numerosos grados de libertad  Open access

     Suarez Feijoo, Raul; Rosell Gratacos, Joan
    Workshop Español de Robótica
    Presentation's date: 2011-11-28
    Presentation of work at congresses

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    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.

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    Teleoperación de manos antropomorfas  Open access

     Suarez Feijoo, Raul; Rosell Gratacos, Joan; Colasanto, Luca
    Workshop Español de Robótica
    Presentation's date: 2011-11-28
    Presentation of work at congresses

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    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.

  • Including virtual constraints in motion planning for anthropomorphic hands

     Rosell Gratacos, Joan; Suarez Feijoo, Raul; Perez Ruiz, Alexander; Rosales Gallegos, Carlos
    IEEE International Symposium on Assembly and Manufacturing
    Presentation's date: 2011-05
    Presentation of work at congresses

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    This paper copes with the problem of finding a collision-free path for a hand-arm robotic system from an initial unconstrained configuration to a final grasping (or preshape) one. The aim is to obtain a natural motion as a sequence of human-like postures that both capture the coupling that there exist between the fingers of the human hand and also maintain the palm oriented towards the object to be grasped. The proposed method is a sampling-based approach whose efficiency relies in the reduction of the dimensionality obtained by considering, for the finger joints, a subspace determined by the main principal motion directions that capture the coupling and, for the position and orientation of the palm, the submanifold that satisfies the orientation constraint. The approach is illustrated with an example and compared to the case where no virtual constrains are used, validating the proposal.

  • Haptic-based navigation for the virtual bronchoscopy

     Cabras, Paolo; Rosell Gratacos, Joan; Perez Ruiz, Alexander; Aguilar, Wilbert G.; Rosell, Antoni
    World Congress of the International Federation of Automatic Control
    Presentation's date: 2011-08
    Presentation of work at congresses

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  • An assisted re-synchronization method for robotic teleoperated tasks

     Perez Ruiz, Alexander; Rosell Gratacos, Joan
    IEEE International Conference on Robotics and Automation
    Presentation's date: 2011-05
    Presentation of work at congresses

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    Teleoperation tasks are performed at cartesian evel when the robot and the haptic device ave dissimilar inematics. If the size of the workspaces is also dissimilar, as it is usually the case, the mapping between workspaces must e handled with care in order to let the user teleoperate the obot in a natural and precise way. This paper formulates the apping of workspaces based on the re-synchronization method nd proposes an assisted system that lightens the user from the edious part of the method, by guiding him/her towards the est re-synchronization position, thus minimizing the number of jumps. The proposal is part of a teleoperated guiding system being developed by the authors.

    Postprint (author’s final draft)

  • Automatic determination of fixturing points: quality analysis for different number of points and friction values

     Rosell Gratacos, Joan; Suarez Feijoo, Raul; Penalba, Francesc
    Date of publication: 2010-09-01
    Book chapter

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  • Haptic Primitives Guidance Based on the Kautham Path Planner

     Vázquez, Carlos; Rosell Gratacos, Joan; Chirinos, Luis; Domínguez, Omar
    IEEE/RSJ International Conference on Intelligent Robots and Systems
    Presentation's date: 2010-10-18
    Presentation of work at congresses

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    Path planning methods are well suited to automatically perform robotic tasks; haptic guidance is a powerful tool for disabled people rehabilitation, sports training, handcraft skills acquiring and such kind of enactive tasks. This paper proposes a novel an efficient method to accomplish guided movements by efficiently combing path planning methods and haptic guidance. The main contribution of this paper is the development of a reliable method to haptically guide the user within a virtual robotic task, by means of: on-line, collision free, path planning generated trajectories. To accomplish haptic guidance three stages must be correctly done: the first one where the user selects the desired objects and obstacles within a virtual environment to set up the task, the second one, where a path planner looks for the task trajectory and, the third one, where the user is constrained to on-line generated local channels and solution paths that offer a reliable path guidance system to achieve the task movements.

    Postprint (author’s final draft)

  • DESARROLLO DE SISTEMAS DE GULADIO EN LA BRONCOSCOPIA(GUIBROD) PARA EL DIAGNÓSTICO DEL NÓDULO PULMONAR PERIFÉRICO

     Basañez Villaluenga, Luis; Suarez Feijoo, Raul; Riego Pérez, Albert; Perez Ruiz, Alexander; Rosell Gratacos, Joan
    Participation in a competitive project

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  • A roadmap to robot motion planning software development

     Perez Ruiz, Alexander; Rosell Gratacos, Joan
    Computer applications in engineering education
    Date of publication: 2009-02-23
    Journal article

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  • Sampling-based path planning for geometrically-constrained objects

     Rodriguez Tsouroukdissian, Adolfo; Perez Ruiz, Alexander; Rosell Gratacos, Joan; Basañez Villaluenga, Luis
    IEEE International Conference on Robotics and Automation
    Presentation's date: 2009-05
    Presentation of work at congresses

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    Efficient search of obstacle-free paths for anthropomorphic hands  Open access

     Suarez Feijoo, Raul; Rosell Gratacos, Joan; Perez Ruiz, Alexander; Rosales Gallegos, Carlos
    IEEE/RSJ International Conference on Intelligent Robots and Systems
    Presentation's date: 2009-10-12
    Presentation of work at congresses

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    The planning of collision-free motions of a handarm system to reach a grasp or preshape configuration is not a simple issue due to the high number of involved degrees of freedom. This paper presents an efficient sampling-based path planner that copes with this issue by considering a reduced search space. The dimension of this space is not fixed but it is iteratively increased according to the difficulty of the task at hand. Initially the search space is 1-dimensional along the line defined by the initial and goal hand configurations (by construction those configurations always belong to the search space), and then its dimension is increased by iteratively adding principal motion directions (that couple the finger motions), trying in this way to produce hand movements through anthropomorphic natural postures.

  • TELETAREA ROBOTIZADA COOPERATIVA EN RED

     Flores Bazaldua, Ignacio; Ayza Graells, Jordi; Rodriguez Tsouroukdissian, Adolfo; Palomo Avellaneda, Leopold; Nuño Ortega, Emmanuel; Rosell Gratacos, Joan; Riego Pérez, Albert; Basañez Villaluenga, Luis
    Participation in a competitive project

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  • A constraint-based probabilistic roadmap planner

     Perez Ruiz, Alexander; Rodríguez, A; Rosell Gratacos, Joan; Basañez Villaluenga, Luis
    40th International Symposium on Robotics
    Presentation's date: 2009-03-10
    Presentation of work at congresses

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  • Analysis of fixturing quality for a variable number of fixturing points and friction values

     Penalba, Francesc; Rosell Gratacos, Joan; Suarez Feijoo, Raul
    IEEE International Symposium on Assembly and Manufacturing
    Presentation's date: 2009-11-17
    Presentation of work at congresses

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    Motion planning for high DOF anthropomorphic hands  Open access

     Rosell Gratacos, Joan; Suarez Feijoo, Raul; Rosales Gallegos, Carlos; Garcia, Jorge Alberto; Perez Ruiz, Alexander
    IEEE International Conference on Robotics and Automation
    Presentation's date: 2009
    Presentation of work at congresses

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    The paper deals with the problem of motion planning of anthropomorphic mechanical hands avoiding collisions. The proposed approach tries to mimic the real human hand motions, but reducing the dimension of the search space in order to obtain results as a compromise between motion optimality and planning complexity (time) by means of the concept of principal motion directions. Basically, the work includes the following phases: capturing the human hand workspace using a sensorized glove and mapping it to the mechanical hand workspace, reducing the space dimension by looking for the most relevant principal motion directions, and planning the hand movements using a sampling-based roadmap planner. The approach has been implemented for a four finger anthropomorphic mechanical hand, and some examples are included to illustrate its validity.

  • Path planning using sub- and super-harmonic functions

     Iñiguez, Pedro; Rosell Gratacos, Joan
    40th International Symposium on Robotics
    Presentation's date: 2009-03-10
    Presentation of work at congresses

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  • Motion Planning for Haptic Guidance

     Rosell Gratacos, Joan; Vázquez, C; Perez Ruiz, Alexander; Iñiguez, Pedro
    Journal of intelligent and robotic systems
    Date of publication: 2008-11
    Journal article

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  • Motion Planning for Haptic Guidance

     Rosell Gratacos, Joan; Vázquez, Carlos; Perez Ruiz, Alexander; Iñiguez, Pedro
    Journal of intelligent and robotic systems: theory and applications (Online)
    Date of publication: 2008-05
    Journal article

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  • Planificación de movimientos en robótica: curso práctico para implementar un PRM

     Perez Ruiz, Alexander; Rosell Gratacos, Joan
    Jornadas de Automática
    Presentation of work at congresses

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  • Exploration of the grasp space using independent contact and non-graspable regions

     Roa, Máximo; Suarez Feijoo, Raul; Rosell Gratacos, Joan
    Date: 2008-04
    Report

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  • Efficient motion planning for high DOF hands using principal motion directions.

     Rosell Gratacos, Joan; Suarez Feijoo, Raul; Rosales, C; García, J A and A Pérez
    Date: 2008-10
    Report

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  • Influence of the sampling strategy on the incremental generation of the grasp space

     Roa, M; Suarez Feijoo, Raul; Rosell Gratacos, Joan
    11th International Conference on Climbing and Walking Robots and the Support Technologies for Mobile Machines, CLAWAR 2008
    Presentation's date: 2008-09-08
    Presentation of work at congresses

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  • Grasp Space Generation Using Sampling and Computation of Independent Regions

     Roa, M; Suarez Feijoo, Raul; Rosell Gratacos, Joan
    IEEE/RSJ International Conference on Intelligent Robots and Systems
    Presentation's date: 2008-06-22
    Presentation of work at congresses

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  • A General Deterministic Sequence for Sampling d-Dimensional Configuration Spaces

     Rosell Gratacos, Joan; Roa, Máximo; Perez Ruiz, Alexander; García, Fernando
    Journal of intelligent and robotic systems
    Date of publication: 2007-07
    Journal article

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  • A performance analysis tool of discrete-events systems

     Peñarroya, A; Casado, F; Rosell Gratacos, Joan
    Date: 2007-01
    Report

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    A novel path planning proposal based on the combination of deterministic sampling and harmonic functions  Open access

     Rosell Gratacos, Joan; Vázquez, C; Pérez, A; Iñíguez, P
    Date: 2007-03
    Report

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    The sampling-based approach is currently the most successful and yet more promising approach to path planning problems. Sampling-based methods are demonstrated to be probabilistic complete, being their performance reliant on the generation of samples. To obtain a good set of samples, this paper proposes a new sampling paradigm based on deterministic sampling paradigm based on a deterministic sampling sequence guided by an harmonic potential function computed on a hierarchical cell decomposition of C-space. In the proposed method, known as Kautham sampler, samples are not isolated configurations but parts of a whole. As samples are generated they are dynamically grouped into cells that capture the C-space structure. This allows the use of harmonic functions to share information and guide further sampling towards more promising regions of C-space. Finally, using the samples obtained, a roadmap is easily built taking advantage of the known neighbourhood relationships.

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    SDK: A proposal of a general and efficient deterministic sampling sequence  Open access

     Rosell Gratacos, Joan; Roa, M; Pérez, A; García, F
    Date: 2007-03
    Report

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    Previous works have already demonstrated that deterministic sampling can be competitive with respect to probabilistic sampling in sampling-based path planners. Nevertheless, the definition of a general sampling sequence for any d-dimensional Configuration Space satisfying the requirements needed for path planning is not a trivial issue, over a multi-grid cell decomposition, of the ordering of the 2d descendant cells of any parent cell. This ordering is generated by the digital construction method using a d x d matrix Td. A general expression of this matrix (i.e. for any d) is introduced and its performance analyzed in terms of the mutual distance. The paper ends with a performance evaluation of the use of the proposed deterministic sampling sequence in different well know path planners

  • C-space decomposition using deterministic sampling and distances

     Rosell Gratacos, Joan; Vázquez, Hurtado C; Perez Ruiz, Alexander
    2007 IEEE/RSJ International Conference on Intelligent Robots ans Systems
    Presentation's date: 2007-10-29
    Presentation of work at congresses

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  • Searching form-closure fixturing points on objects described by triangular meshes

     Suarez Feijoo, Raul; Rosell Gratacos, Joan
    2007 IEEE International Symposium Conference on Assembly and Manufacturing, ISAM'2007
    Presentation's date: 2007-07-22
    Presentation of work at congresses

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  • Haptic Guidance based on Harmonic Functions for the Execution of Teleoperated Assembly tasks

     Vázquez, Carlos; Rosell Gratacos, Joan
    IFAC Workshop on Intelligent Assembly and Disassembly
    Presentation's date: 2007-05-23
    Presentation of work at congresses

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