http://hdl.handle.net/2117/7012 Sat, 25 May 2013 00:09:39 GMT 2013-05-25T00:09:39Z webmaster.bupc@upc.edu Universitat Politècnica de Catalunya. Servei de Biblioteques i Documentació no http://hdl.handle.net/2117/18133 Title: Coordination of multi-agent systems via energy–shaping: networking improves robustness Authors: Nuño Ortega, Emmanuel; Ortega, Romeo; Jayawardhana, Bayu; Basañez Villaluenga, Luis Abstract: In this paper the problem of robust coordination of multi–agent systems via energy–shaping is studied. The agents are nonidentical, Euler–Lagrange systems with uncertain parameters. The control objective is to drive all agents states to the same constant equilibrium— which is achieved shaping their potential energy function. It is assumed that, if the parameters are known, this task can be accomplished with a decentralized strategy. In the face of parameter uncertainty, the assigned equilibrium is shifted away from its desired value. It is shown that adding information exchange between the agents to this decentralized control policy improves the performance. More precisely, it is proven that if the communication graph is undirected and connected, the equilibrium of the networked controller is always closer (in a suitable metric) to the desired one. If the the potential energy functions are quadratic, the result holds for all interconnection gains, else, it is true for sufficiently large gains. The decentralized controller is the well–known energy–shaping proportional plus derivative controller, extensively used in applications. An additional advantage of networking is that the control objective is achieved injecting lower gains into the loop. Thu, 07 Mar 2013 13:26:31 GMT http://hdl.handle.net/2117/18133 2013-03-07T13:26:31Z Nuño Ortega, Emmanuel; Ortega, Romeo; Jayawardhana, Bayu; Basañez Villaluenga, Luis no In this paper the problem of robust coordination of multi–agent systems via energy–shaping is studied. The agents are nonidentical, Euler–Lagrange systems with uncertain parameters. The control objective is to drive all agents states to the same constant equilibrium— which is achieved shaping their potential energy function. It is assumed that, if the parameters are known, this task can be accomplished with a decentralized strategy. In the face of parameter uncertainty, the assigned equilibrium is shifted away from its desired value. It is shown that adding information exchange between the agents to this decentralized control policy improves the performance. More precisely, it is proven that if the communication graph is undirected and connected, the equilibrium of the networked controller is always closer (in a suitable metric) to the desired one. If the the potential energy functions are quadratic, the result holds for all interconnection gains, else, it is true for sufficiently large gains. The decentralized controller is the well–known energy–shaping proportional plus derivative controller, extensively used in applications. An additional advantage of networking is that the control objective is achieved injecting lower gains into the loop. http://hdl.handle.net/2117/18122 Title: A proportional plus damping injection controller for teleoperators with joint fexibility and time–delays Authors: Nuño Ortega, Emmanuel; Sarras, Ioannis; Basañez Villaluenga, Luis; Kinnaert, Michel Abstract: The problem of controlling a rigid bilateral teleoperator with time-delays has been effectively addressed since the late 80’s. However, the control of flexible joint manipulators in a bilateral teleoperation scenario is still an open problem. In the present paper we report two versions of a proportional plus damping injection controller that are capable of globally stabilizing a nonlinear bilateral teleoperator with joint flexibility and variable time-delays. The first version controls a teleoperator composed by a rigid local manipulator and a flexible joint remote manipulator and the second version deals with local and remote manipulators with joint flexibility. For both schemes, it is proved that the joint and motor velocities and the local and remote position error are bounded. Moreover, if the human operator and remote environment forces are zero then velocities asymptotically converge to zero and position tracking is established. Simulations are presented to show the performance of the proposed controllers. Thu, 07 Mar 2013 12:05:43 GMT http://hdl.handle.net/2117/18122 2013-03-07T12:05:43Z Nuño Ortega, Emmanuel; Sarras, Ioannis; Basañez Villaluenga, Luis; Kinnaert, Michel no The problem of controlling a rigid bilateral teleoperator with time-delays has been effectively addressed since the late 80’s. However, the control of flexible joint manipulators in a bilateral teleoperation scenario is still an open problem. In the present paper we report two versions of a proportional plus damping injection controller that are capable of globally stabilizing a nonlinear bilateral teleoperator with joint flexibility and variable time-delays. The first version controls a teleoperator composed by a rigid local manipulator and a flexible joint remote manipulator and the second version deals with local and remote manipulators with joint flexibility. For both schemes, it is proved that the joint and motor velocities and the local and remote position error are bounded. Moreover, if the human operator and remote environment forces are zero then velocities asymptotically converge to zero and position tracking is established. Simulations are presented to show the performance of the proposed controllers. http://hdl.handle.net/2117/18117 Title: An adaptive controller for bilateral teleoperators: transatlantic experiments using the internet Authors: Nuño Ortega, Emmanuel; Basañez Villaluenga, Luis; de Alba Padilla, Carlos; López Franco, Carlos Abstract: A bilateral teleoperator is composed of a local and a remote manipulators interconnected through a communication channel. A human operator interacts with the local manipulator to remotely execute a given task via the remote manipulator and the interaction of the remote manipulator with the remote environment is reflected back to the human operator. Thus, the control objective is to establish local and remote position synchronization. This paper employs adaptive control techniques, that can achieve the desired control objective, to an experimental setup composed of two nonlinear manipulators. In these novel experimental results the local and remote manipulators are located in Guadalajara, Mexico, and in Barcelona, Spain, respectively. The manipulators are two Sensable's PHANToM Omni® devices and are interconnected through the Internet. It is shown, experimentally, that the adaptive controllers provide asymptotic stability of the local and remote position error even in the presence of variable timedelays. Thu, 07 Mar 2013 11:19:37 GMT http://hdl.handle.net/2117/18117 2013-03-07T11:19:37Z Nuño Ortega, Emmanuel; Basañez Villaluenga, Luis; de Alba Padilla, Carlos; López Franco, Carlos no A bilateral teleoperator is composed of a local and a remote manipulators interconnected through a communication channel. A human operator interacts with the local manipulator to remotely execute a given task via the remote manipulator and the interaction of the remote manipulator with the remote environment is reflected back to the human operator. Thus, the control objective is to establish local and remote position synchronization. This paper employs adaptive control techniques, that can achieve the desired control objective, to an experimental setup composed of two nonlinear manipulators. In these novel experimental results the local and remote manipulators are located in Guadalajara, Mexico, and in Barcelona, Spain, respectively. The manipulators are two Sensable's PHANToM Omni® devices and are interconnected through the Internet. It is shown, experimentally, that the adaptive controllers provide asymptotic stability of the local and remote position error even in the presence of variable timedelays. http://hdl.handle.net/2117/18116 Title: Consensus in networks of nonidentical Euler-Lagrange systems with variable time-delays Authors: Nuño Ortega, Emmanuel; Sarras, Ioannis; Panteley, Elena; Basañez Villaluenga, Luis Abstract: The present work reports a sufficient condition for the consensus of a network of nonidentical Euler-Lagrange (EL) systems with variable time-delays in the communications. The EL-systems are controlled by simple Proportional plus damping (P+d) schemes and the interconnection network is modeled as an undirected weighted graph. Additionally, for the case without delays, the paper reports a new Strict Lyapunov Function (SLF)for the closed-loop system. Experimental evidence, using three 3-Degrees-of-Freedom manipulators interconnected through the Internet, support the theoretical results of this paper. Thu, 07 Mar 2013 10:40:21 GMT http://hdl.handle.net/2117/18116 2013-03-07T10:40:21Z Nuño Ortega, Emmanuel; Sarras, Ioannis; Panteley, Elena; Basañez Villaluenga, Luis no The present work reports a sufficient condition for the consensus of a network of nonidentical Euler-Lagrange (EL) systems with variable time-delays in the communications. The EL-systems are controlled by simple Proportional plus damping (P+d) schemes and the interconnection network is modeled as an undirected weighted graph. Additionally, for the case without delays, the paper reports a new Strict Lyapunov Function (SLF)for the closed-loop system. Experimental evidence, using three 3-Degrees-of-Freedom manipulators interconnected through the Internet, support the theoretical results of this paper. 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/2117/17829 Title: Using path planning techniques to improve airway tree segmentation from CT images Authors: Cabras, Paolo; Rosell Gratacòs, Jan Abstract: 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. Mon, 18 Feb 2013 13:09:52 GMT http://hdl.handle.net/2117/17829 2013-02-18T13:09:52Z Cabras, Paolo; Rosell Gratacòs, Jan no 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. 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/2117/16587 Title: Device for a hand: with mobility and sensitivity but without force Authors: Peña Pitarch, Esteve; Ticó Falguera, Neus; López Martínez, Joan Antoni; Abenoza Guardiola, Montserrat; Romero Cullerés, Georgia Abstract: People with disabilities have limitations in activities of daily life such as grasping a glass of water or moving and object. Orthotic products that improve or restore the funcionality of the musculoskeletal system of a patient contribute to some extent to overcome the limitations described. So does the hand brace, used to treat musculosketal disorders caused by various diseases (rheumatic disorders, neurological, orthopedic and others). The paper shows a novel exoskeleton to grasp any object. The novelty of this mechanism is that works without external energy, it works with a wrist movement that generates a kinetic movement and helps to grasp with an extra force Wed, 26 Sep 2012 15:25:51 GMT http://hdl.handle.net/2117/16587 2012-09-26T15:25:51Z Peña Pitarch, Esteve; Ticó Falguera, Neus; López Martínez, Joan Antoni; Abenoza Guardiola, Montserrat; Romero Cullerés, Georgia no People with disabilities have limitations in activities of daily life such as grasping a glass of water or moving and object. Orthotic products that improve or restore the funcionality of the musculoskeletal system of a patient contribute to some extent to overcome the limitations described. So does the hand brace, used to treat musculosketal disorders caused by various diseases (rheumatic disorders, neurological, orthopedic and others). The paper shows a novel exoskeleton to grasp any object. The novelty of this mechanism is that works without external energy, it works with a wrist movement that generates a kinetic movement and helps to grasp with an extra force http://hdl.handle.net/2117/16525 Title: Fingertips deformation under static forces: analysis and experiments Authors: Peña Pitarch, Esteve; Ticó Falguera, Neus; Vinyes Casasayas, Adrià; Martinez Carmona, Damián Abstract: Introduction: When designers, physicians, and engineers are working in a new design or calculation forces exerted by fingertips they need to consider that each person's fingertip is different. Taking into account the material properties for each person the Poisson's ratio, Young,s modulus, and density are different. These properties will be influential in the fingertip force. Objectives: Development of a three-dimensional human fingertip model to simulate with finite element methods a behavior of soft finger when it is under a force. In a soft finger, Poisson´s coefficient can be different according to person and age. Other factors like temperature have influence on this coefficient. Young,s modulus can be used for the dermis, epidermis, soft tissue, grease, and tendons. Once we have collected all of these dates we create a three-dimensional model. Methods: With a caliper and a precision balance Tefal-EASY we measure three times the force and deformation of fingertips, with O N no deformation to 7 N maximum deformation in z-axis (axis normal to balance and fingertip) using the same conditions for each experiment. Once we have done experiments with a person we introduce constrains in a finite element program to campare deformation in z-axis and force with the results and experiments. Thu, 20 Sep 2012 07:42:33 GMT http://hdl.handle.net/2117/16525 2012-09-20T07:42:33Z Peña Pitarch, Esteve; Ticó Falguera, Neus; Vinyes Casasayas, Adrià; Martinez Carmona, Damián no Introduction: When designers, physicians, and engineers are working in a new design or calculation forces exerted by fingertips they need to consider that each person's fingertip is different. Taking into account the material properties for each person the Poisson's ratio, Young,s modulus, and density are different. These properties will be influential in the fingertip force. Objectives: Development of a three-dimensional human fingertip model to simulate with finite element methods a behavior of soft finger when it is under a force. In a soft finger, Poisson´s coefficient can be different according to person and age. Other factors like temperature have influence on this coefficient. Young,s modulus can be used for the dermis, epidermis, soft tissue, grease, and tendons. Once we have collected all of these dates we create a three-dimensional model. Methods: With a caliper and a precision balance Tefal-EASY we measure three times the force and deformation of fingertips, with O N no deformation to 7 N maximum deformation in z-axis (axis normal to balance and fingertip) using the same conditions for each experiment. Once we have done experiments with a person we introduce constrains in a finite element program to campare deformation in z-axis and force with the results and experiments. 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/2117/16024 Title: Motion planning for the virtual bronchoscopy Authors: Rosell Gratacòs, Jan; Pérez Ruiz, Alexander; Cabras, Paolo; Rosell, Antoni Abstract: 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. Tue, 12 Jun 2012 10:41:09 GMT http://hdl.handle.net/2117/16024 2012-06-12T10:41:09Z Rosell Gratacòs, Jan; Pérez Ruiz, Alexander; Cabras, Paolo; Rosell, Antoni no 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. http://hdl.handle.net/2117/15465 Title: Trajectory tracking and consensus of networks of Euler–Lagrange systems Authors: Nuño Ortega, Emmanuel; Ortega, Romeo; Basañez Villaluenga, Luis; Hill, David Abstract: This paper addresses the problem of synchronizing networks of nonidentical, nonlinear dynamical systems described by Euler–Lagrange equations. It is assumed that the communication graph is simply connected and that the systems are fully actuated, with their states available for measurement. The communications can be subject to constant time-delays. The main result of the paper is a controller for each system in the network, capable of tracking a desired trajectory and, if such trajectory does not exist, capable of reaching a network consensus. Moreover, it is proved that, if there are no time-delays and the graph is balanced each system reaches a consensus arbitrarily near the average of the initial conditions of all the systems in the network. Simulations using a ten robot manipulator network with different time-delays are provided. Fri, 02 Mar 2012 13:27:48 GMT http://hdl.handle.net/2117/15465 2012-03-02T13:27:48Z Nuño Ortega, Emmanuel; Ortega, Romeo; Basañez Villaluenga, Luis; Hill, David no This paper addresses the problem of synchronizing networks of nonidentical, nonlinear dynamical systems described by Euler–Lagrange equations. It is assumed that the communication graph is simply connected and that the systems are fully actuated, with their states available for measurement. The communications can be subject to constant time-delays. The main result of the paper is a controller for each system in the network, capable of tracking a desired trajectory and, if such trajectory does not exist, capable of reaching a network consensus. Moreover, it is proved that, if there are no time-delays and the graph is balanced each system reaches a consensus arbitrarily near the average of the initial conditions of all the systems in the network. Simulations using a ten robot manipulator network with different time-delays are provided.