Basañez Villaluenga, Luis
Total activity: 218

## Scientific and technological production Ordered by:  Date asc. Date desc. Title asc. Title desc. Researcher asc. Researcher desc.

1 to 50 of 218 results
• Stability of nonlinear teleoperators using PD controllers without velocity measurements

Nuño, Emmanuel; Basañez Villaluenga, Luis; Lopez Franco, Carlos; Arana Daniel, Nancy
Journal of the Franklin Institute
Date of publication: 2014-01
Journal article

This paper presents two Proportional-Derivative (PD) like controllers for nonlinear bilateral teleoperation systems. Compared to previous controllers of this kind, these schemes do not make use of velocity measurements. Under the assumptions that the human operator and the environment define passive maps from velocity to force, both controllers can ensure boundedness of velocities and position error. Moreover, in the case that the human and environment forces are zero, the controllers ensure velocity and position synchronization. Furthermore, the paper also presents a generalization to the case of teleoperation of networks of multiple robots. Simulations and real experiments, comparing the performance on free motion and interacting with a stiff wall, support the performance of the reported schemes. The experiments have been performed using two 3-degree-of-freedom nonlinear manipulators.

• Operational space consensus in networks of robots: The leader-follower case

Aldana Lopez, Carlos Ivan; Romero, Eduardo; Nuño, Emmanuel; Basañez Villaluenga, Luis
Date of publication: 2013-12-26
Book chapter

Nuño, Emmanuel; Valle, Daniela; Sarras, Ioannis; Basañez Villaluenga, Luis
Congreso Nacional de la Asociación Mexicana de Control Automático
Presentation's date: 2013-10-16
Presentation of work at congresses

• Consensus of networks of nonidentical robots with flexible joints, variable time--delays and unmeasurable velocities

Valle, Daniela; Nuño, Emmanuel; Basañez Villaluenga, Luis; Arana Daniel, Nancy
IEEE/RSJ International Conference on Intelligent Robots and Systems
Presentation's date: 2013-11-06
Presentation of work at congresses

The present paper proposes two controllers for solving a consensus problem to a given desired position of networks composed of a class of under actuated mechanical systems: flexible joints robots. One of the controllers makes use of joint (motor) velocity signals while the other only uses joint positions. The only assumption on the directed and weighted interconnection graph is that it is connected. Further, the interconnection may induce variable time¿delays. The paper presents some experiments, using three 3-Degrees of Freedom manipulators, which show the performance of the proposed approaches.

• Bilateral teleoperation of flexible-joint manipulators with dynamic gravity compensation and variable time-delays

Nuño, Emmanuel; Valle, Daniela; Sarras, Ioannis; Basañez Villaluenga, Luis
IEEE/RSJ International Conference on Intelligent Robots and Systems
Presentation's date: 2013-11-06
Presentation of work at congresses

It is widely known that 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, with dynamic gravity compensation, remains an open problem. This work aims at filling this gap by presenting a new controller for bilateral teleoperators composed of a rigid local manipulator and a flexible-joint remote manipulator with dynamic gravity compensation and asymmetric variable timedelays in the communication channel. In order to dynamically compensate the gravity term, in the flexible joint manipulator, a change of coordinates which accounts for the joint and link gravity position drift is used. The rest of the controller is a simple PD scheme. Assuming that the human operator and the environment define passive maps from velocity to force, it is proved that velocities and local and remote position errors are bounded. Additionally, if the human operator and remote environment forces are zero then velocities asymptotically converge to zero and position tracking is established. Some simulations are presented in order to show the performance of the proposed controllers.

• Control of bilateral teleoperators in operational space without velocity measurements

Aldana Lopez, Carlos Ivan; Nuño, Emmanuel; Basañez Villaluenga, Luis
IEEE/RSJ International Conference on Intelligent Robots and Systems
Presentation's date: 2013-11-06
Presentation of work at congresses

This paper proposes a proportional plus damping injection (P + d) controller for bilateral teleoperators in the operational space. Unit quaternions are used to describe the endeffectors¿ orientation since they exhibit the well known property of being a singularity-free representation. The proposed controller does not need the measurement of the velocities, instead a passivity¿based filter is used. Under the reasonable assumptions that the human operator and the environment define passive maps from force to velocity, it is proved that velocities and pose (position and orientation) errors between the local and the remote manipulators are bounded. Moreover, in the case that the human and the environment forces are zero, the velocities and pose errors converge asymptotically to zero. Finally, experimental validation using two robots of 6-Degreesof- Freedom (DoF) shows the effectiveness of the proposed control scheme.

• Consensus of networks of nonidentical robots with flexible joints, variable time-delays and immeasurable velocities

Valle, Daniela; Nuño, Emmanuel; Basañez Villaluenga, Luis; Arana Daniel, Nancy
IEEE/RSJ International Conference on Intelligent Robots and Systems
Presentation of work at congresses

The present paper proposes two controllers for solving a consensus problem to a given desired position of networks composed of a class of under actuated mechanical systems: flexible joints robots. One of the controllers makes use of joint (motor) velocity signals while the other only uses joint positions. The only assumption on the directed and weighted interconnection graph is that it is connected. Further, the interconnection may induce variable time-delays. The paper presents some experiments, using three 3-Degrees of Freedom manipulators, which show the performance of the proposed approaches.

• Modeling non-linear viscoelastic behavior under large deformations

del Castillo Pérez, Esteban; Basañez Villaluenga, Luis; Gil Dolcet, Ernest
International journal of non-linear mechanics
Date of publication: 2013-12
Journal article

This paper addresses the accurate modeling of the behavior of a thin layer of natural rubber subjected to large deformations. Such a system presents a non-linear viscoelastic behavior similar to many biological soft tissues. The proposed model uses an spring-mass system, and considers a non-linear evolution of the reaction forces of the membrane, as well as viscous and Coulomb friction. In the model, the elasticity coefficient of the springs has an exponential dependence of its elongation. Three experimental tests validate the proposed model, which reaches a real-time performance using an implicit integrator.

This paper addresses the accurate modeling of the behavior of a thin layer of natural rubber subjected to large deformations. Such a system presents a non-linear viscoelastic behavior similar to many biological soft tissues. The proposed model uses an spring-mass system, and considers a non-linear evolution of the reaction forces of the membrane,as well as viscous and Coulomb friction. In the model, the elasticity coefficient of the springs has an exponential dependence of its elongation. Three experimental tests validate the proposed model, which reaches a real-time performance using an implicit integrator

• Networking improves robustness in flexible-joint multi-robot systems with only joint position measurements

Nuño, Emmanuel; Ortega, Romeo; Jayawardhana, Bayu; Basañez Villaluenga, Luis
European journal of control
Date of publication: 2013-12
Journal article

This paper studies the robustness in the coordination - via energy-shaping - of multiple nonidentical flexible-joint robots with only joint position measurements. The control objective is to drive all manipulators link positions to the same constant equilibrium. If the physical parameters are exactly known, then a classical decentralized energy-shaping controller solves the desired control objective. However, under parameter uncertainty, the globally asymptotically stable equilibrium point is shifted away from the desired value. The main contribution of the paper is to show that the steady-state performance is improved adding to the decentralized control policy information exchange between the agents. More precisely, it is proven that the equilibrium with the networked controller is always closer (in a suitable metric) to the desired one than that using the decentralized controller, provided the communication graph representing the network is undirected and connected. This result holds globally for sufficiently large interconnection gains and locally (in a suitably defined sense) for all values of the gains. An additional advantage of networking is that the asymptotic stabilization objective can be achieved injecting lower gains into the loop. The paper also provides simulation and experimental evidence, which illustrate the fact that networking improves robustness with respect to parameter uncertainty.

• Coordination of multi-agent Euler-Lagrange systems via energy-shaping: Networking improves robustness

Nuño, Emmanuel; Ortega, Romeo; Jayawardhana, Bayu; Basañez Villaluenga, Luis
Automatica
Date of publication: 2013-10-01
Journal article

In this paper, the robust coordination of multi-agent systems via energy-shaping is studied. The agents are nonidentical, Euler¿Lagrange systems with uncertain parameters which are regulated (with and without exchange of information between the agents) by the classical energy-based controller where the potential energy function is shaped such that, if the parameters are known, all agents converge globally to the same desired constant equilibrium. Under parameter uncertainty, the globally asymptotically stable (GAS) equilibrium point is shifted away from its desired value and this paper shows that adding information exchange between the agents to the decentralized control policy improves the steady-state performance. More precisely, it proves that if the undirected communication graph is connected, the equilibrium of the networked controller isalways closer (in a suitable metric) to the desired one than that of the decentralized controller. The result holds for all interconnection gains if the potential energy functions are quadratic, else, it is true for sufficiently large gains. An additional advantage of networking is that the asymptotic stabilization objective can be achieved by using lower gains into the loop. Some experimental results (using two nonlinear manipulators) given support to the main results of the paper

• Consensus in networks of nonidentical Euler-Lagrange systems using P plus d controllers

Nuño, Emmanuel; Sarras, Ioannis; Basañez Villaluenga, Luis
IEEE transactions on robotics
Date of publication: 2013-12
Journal article

This paper presents a proportional plus damping controller that can asymptotically drive a network composed of N nonidentical Euler-Lagrange (EL) systems toward a consensus point. The agents can be fully actuated or can belong to a class of underactuated EL-systems. The network is modeled as a weighted and undirected static interconnection graph that can exhibit asymmetric variable time delays. Simulations, using a network with ten EL-systems, are reported to support the theoretical contributions of this study.

• Grasp plannind under task-specific contact constraints

Rosales Gallegos, Carlos José
Defense's date: 2013-01-10
Institute of Industrial and Control Engineering (IOC), Universitat Politècnica de Catalunya
Theses

Several aspects have to be addressed before realizing the dream of a robotic hand-arm system with human-like capabilities, ranging from the consolidation of a proper mechatronic design, to the development of precise, lightweight sensors and actuators, to the efficient planning and control of the articular forces and motions required for interaction with the environment. This thesis provides solution algorithms for a main problem within the latter aspect, known as the {\em grasp planning} problem: Given a robotic system formed by a multifinger hand attached to an arm, and an object to be grasped, both with a known geometry and location in 3-space, determine how the hand-arm system should be moved without colliding with itself or with the environment, in order to firmly grasp the object in a suitable way. Central to our algorithms is the explicit consideration of a given set of hand-object contact constraints to be satisfied in the final grasp configuration, imposed by the particular manipulation task to be performed with the object. This is a distinguishing feature from other grasp planning algorithms given in the literature, where a means of ensuring precise hand-object contact locations in the resulting grasp is usually not provided. These conventional algorithms are fast, and nicely suited for planning grasps for pick-an-place operations with the object, but not for planning grasps required for a specific manipulation of the object, like those necessary for holding a pen, a pair of scissors, or a jeweler's screwdriver, for instance, when writing, cutting a paper, or turning a screw, respectively. To be able to generate such highly-selective grasps, we assume that a number of surface regions on the hand are to be placed in contact with a number of corresponding regions on the object, and enforce the fulfilment of such constraints on the obtained solutions from the very beginning, in addition to the usual constraints of grasp restrainability, manipulability and collision avoidance. The proposed algorithms can be applied to robotic hands of arbitrary structure, possibly considering compliance in the joints and the contacts if desired, and they can accommodate general patch-patch contact constraints, instead of more restrictive contact types occasionally considered in the literature. It is worth noting, also, that while common force-closure or manipulability indices are used to asses the quality of grasps, no particular assumption is made on the mathematical properties of the quality index to be used, so that any quality criterion can be accommodated in principle. The algorithms have been tested and validated on numerous situations involving real mechanical hands and typical objects, and find applications in classical or emerging contexts like service robotics, telemedicine, space exploration, prosthetics, manipulation in hazardous environments, or human-robot interaction in general.

• Estimación de la forma de un objeto deformable mediante integración de visión y tacto

Del Castillo pérez, Esteban
Defense's date: 2013-09-30
Universitat Politècnica de Catalunya
Theses

• Bilateral Teleoperation of Cooperative Manipulators

Aldana, Carlos; Basañez Villaluenga, Luis
IEEE International Conference on Robotics and Automation
Presentation's date: 2012
Presentation of work at congresses

This paper presents an adaptive controller for the bilateral teleoperation of a system composed by a single local manipulator and multiple cooperative remote manipulators handling a common object. First, the nonlinear operational space dynamical behavior of the complete teleoperation system is derived. Then, under the assumptions that the remote manipulators are rigidly grasping a non-deformable object and that the communications may induce constant time-delays, it is proved that velocities and position-orientation error between the local manipulator end-effector and the object asymptotically converge to zero. Simulations results are included to show the effectiveness of the proposed approach.

• Coordination of multi-agent systems via energy¿shaping: networking improves robustness

Nuño Ortega, Emmanuel; Ortega, Romeo; Jayawardhana, Bayu; Basañez Villaluenga, Luis
IFAC Workshop on Lagrangian and Hamiltonian Methods for Non Linear Control
Presentation's date: 2012-08-29
Presentation of work at congresses

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.

• An adaptive controller for bilateral teleoperators: transatlantic experiments using the internet

Nuño, Emmanuel; Basañez Villaluenga, Luis; de Alba Padilla, Carlos; López Franco, Carlos
World Automation Congress
Presentation's date: 2012-06-25
Presentation of work at congresses

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.

• Output-feedback control of nonlinear bilateral teleoperators

Sarras, Ioannis; Nuño, Emmanuel; Kinnaert, Michel; Basañez Villaluenga, Luis
American Control Conference
Presentation's date: 2012
Presentation of work at congresses

The output-feedback design problem for a bilateral teleoperator scheme is considered. The recently proposed Immersion and Invariance (I&I) observer is used to obtain an exponentially convergent estimate of the unmeasured velocities. Moreover, it is proven that when this observer is interconnected to the nonlinear teleoperator together with a Proportional plus damping (P+d) controller, the overall system is globally stable. Finally, in the case when the human operator and the environment do not exert forces on the local and remote manipulator, respectively, global asymptotic convergence to zero of the velocities and of the position tracking error is achieved. These results are obtained by introducing two important design modifications ensuring the explicit derivation of the observer dynamics and that the interconnected system inherits the same stability properties as in the full-measurement case. The theoretical results are illustrated with simulations using local and remote two degree-of-freedom nonlinear manipulators.

• A proportional plus damping injection controller for teleoperators with joint fexibility and time¿delays

Nuño, Emmanuel; Sarras, Ioannis; Basañez Villaluenga, Luis; Kinnaert, Michel
IEEE International Conference on Robotics and Automation
Presentation's date: 2012-05-14
Presentation of work at congresses

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.

• Consensus in networks of nonidentical Euler-Lagrange systems with variable time-delays

Nuño, Emmanuel; Sarras, Ioannis; Panteley, Elena; Basañez Villaluenga, Luis
IEEE Conference on Decision and Control
Presentation's date: 2012-12-10
Presentation of work at congresses

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.

• Asistencia háptica basada en planificación de movimientos para la teleoperación cooperativa de sistemas multirobot

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

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.

• Distance-Based Formulations For The Position Analysis Of Kinematic Chains

Rojas Libreros, Nicolás Enrique
Defense's date: 2012-06-20
Institute of Industrial and Control Engineering (IOC), Universitat Politècnica de Catalunya
Theses

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

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

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

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

• 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
Participation in a competitive project

• A framework for robotized teleoperated tasks

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

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.

• Bilateral teleoperation control without velocity measurements

Nuño, Emmanuel; Basañez Villaluenga, Luis; Obregón-Pulido, Guillermo; Solís-Perales, Gualberto
World Congress of the International Federation of Automatic Control
Presentation's date: 2011-09-01
Presentation of work at congresses

This paper presents two controllers for a nonlinear bilateral teleoperation system that do not rely on velocity measurements. Under the reasonable assumptions that the human operator and the environment define passive maps from force to velocity, both controllers can ensure boundedness of velocities and position error. Moreover, if the human and environment forces are bounded, one of the controllers ensure velocity synchronization and the other velocity convergence to zero. Simulations, comparing the performance on free motion and interacting with a stiff wall, support the performance of the reported schemes.

• Trajectory tracking and consensus of networks of Euler¿Lagrange systems

Nuño, Emmanuel; Ortega, Romeo; Basañez Villaluenga, Luis; Hill, David
World Congress of the International Federation of Automatic Control
Presentation's date: 2011-09-01
Presentation of work at congresses

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.

• Synchronization of networks of nonidentical Euler-Lagrange systems with uncertain parameters and communication delays

Nuño Ortega, Emmanuel; Ortega, Romeo; Basañez Villaluenga, Luis; Hill, David
IEEE transactions on automatic control
Date of publication: 2011-04
Journal article

• Erratum to An adaptive controller for nonlinear teleoperators"

Nuño, Emmanuel; Ortega, Romeo; Basañez Villaluenga, Luis
Automatica
Date of publication: 2011-05-01
Journal article

• Passivity-based control for bilateral teleoperation: A tutorial

Nuño, Emmanuel; Basañez Villaluenga, Luis; Ortega, Romeo
Automatica
Date of publication: 2011-03
Journal article

This tutorial revisits several of the most recent passivity-based controllers for nonlinear bilateral teleoperators with guaranteed stability properties. These schemes, which include scattering–based, damping injection and adaptive controllers, ensure asymptotic stability in multiple situations that range from constant to variable time-delays, with or without scattering transformation and with or without position tracking capabilities. Although all controllers exploit the basic property of passivity of the teleoperators, they have been developed invoking various analysis and design tools, which complicates their comparison and relative performance assessment. The objective of this paper is to present a unified theoretical framework—based on a general Lyapunov–like function—that, upon slight modification, allows to analyze the stability of all the schemes.

• Singularity-invariant leg rearrangements in stewart-gouch platforms

Borras Sol, Julia
Defense's date: 2011-04-15
Institute of Industrial and Control Engineering (IOC), Universitat Politècnica de Catalunya
Theses

• Nonlinear control and geometric constraint enforcement for teleoperated task execution

Rodriguez Tsouroukdissian, Adolfo; Nuño, Emmanuel; Palomo Avellaneda, Leopold; Basañez Villaluenga, Luis
IEEE/RSJ International Conference on Intelligent Robots and Systems
Presentation's date: 2010-10-18
Presentation of work at congresses

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.

• Position tracking using adaptive control for bilateral teleoperators with time-delays

Nuño, Emmanuel; Basañez Villaluenga, Luis; Ortega, Romeo; Obregón-Pulido, Guillermo
IEEE International Conference on Robotics and Automation
Presentation's date: 2010-05-03
Presentation of work at congresses

This paper presents two versions of adaptive controllers for nonlinear bilateral teleoperators, each providing asymptotic convergence of velocity and position errors to zero, independent of constant time-delays. Moreover, the proposed schemes do not rely on the use of the scattering transformation. The paper also proves that the teleoperator is Input-to-State Stable from human operator and environment inputs to some synchronization signals. Simulations show the effectiveness of the proposed controllers.

• Adaptive control for the synchronization of multiple robot manipulators with coupling time-delays

Nuño, Emmanuel; Basañez Villaluenga, Luis; Ortega, Romeo
IEEE/RSJ International Conference on Intelligent Robots and Systems
Presentation's date: 2010-10-18
Presentation of work at congresses

Two controllers capable of achieving asymptotic convergence of position and velocity errors, of the ithmanipulator within a multiple robot network, are proposed. The controllers employ adaptive techniques to find an estimate of the physical parameters of the nonlinear dynamics of the robot network. Moreover, the controllers can deal with different connectivity topologies (ring and star) and and can handle timedelays in the communications. Simulations, using a ten robot manipulators network with different connectivity topologies, that confirm the theoretical results are presented.

• An adaptive controller for nonlinear teleoperators

Nuño Ortega, Emmanuel; Ortega, Romeo; Basañez Villaluenga, Luis
Automatica
Date of publication: 2010-01
Journal article

• Robust perceptual organization techniques for analysis of color images

Moreno Serrano, Rodrigo
Defense's date: 2010-11-15
Institute of Industrial and Control Engineering (IOC), Universitat Politècnica de Catalunya
Theses

This thesis focuses on the development of new robust image analysis techniques more closely related to the way the human visual system behaves. One of the pillars of the thesis is the so called tensor voting technique. This is a robust perceptual organization technique that propagates and aggregates information encoded by means of tensors through a convolution like process. Its robustness and adaptability have been one of the key points for using tensor voting in this thesis. These two properties are verified in the thesis by applying tensor voting to three applications where it had not been applied so far: image structure estimation, edge detection and image segmentation of images acquired through stereo vision.The most important drawback of tensor voting is that its usual implementations are highly time consuming. In this line, this thesis proposes two new efficient implementations of tensor voting, both derived from an in depth analysis of this technique.Despite its adaptability, this thesis shows that the original formulation of tensor voting (hereafter, classical tensor voting) is not adequate for some applications, since the hypotheses from which it is based are not suitable for all applications. This is particularly certain for color image denoising. Thus, this thesis shows that, more than a method, tensor voting can be thought of as a methodology in which the encoding and voting process can be tailored for every specific application, while maintaining the tensor voting spirit.By following this reasoning, this thesis proposes a unified framework for both image denoising and robust edge detection.This framework is an extension of the classical tensor voting in which both color and edginess the likelihood of finding an edge at every pixel of the image are encoded through tensors, and where the voting process takes into account a set of plausible perceptual criteria related to the way the human visual system processes visual information. Recent advances in the perception of color have been essential for designing such a voting process.This new approach has been found effective, since it yields excellent results for both applications. In particular, the new method applied to image denoising has a better performance than other state of the art methods for real noise. This makes it more adequate for real applications, in which an image denoiser is indeed required. In addition, the method applied to edge detection yields more robust results than the state of the art techniques and has a competitive performance in recall, discriminability, precision, and false alarm rejection.Moreover, this thesis shows how the results of this new framework can be combined with other techniques to tackle the problem of robust color image segmentation. The tensors obtained by applying the new framework are utilized to classify pixels into likely homogeneous and likely inhomogeneous. Those pixels are then sequentially segmented through a variation of an efficient graph based image segmentation algorithm. Experiments show that the proposed segmentation algorithm yields better scores in three of the five applied evaluation metrics when compared to the state of the art techniques with a competitive computational cost.This thesis also proposes new evaluation techniques in the scope of image processing. First, two new metrics are proposed in the field of image denoising: one to measure how an algorithm is able to preserve edges, and the second to measure how a method is able not to introduce undesirable artifacts. Second, a new methodology for assessing edge detectors that avoids possible bias introduced by post processing is proposed. It consists of five new metrics for assessing recall, discriminability, precision, false alarm rejection and robustness. Finally, two new non parametric metrics are proposed for estimating the degree of over and undersegmentation yielded by image segmentation algorithms.

• Comité Español de Automática

Basañez Villaluenga, Luis
Award or recognition

• 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

• A Framework for the simulation and haptic display of dynamic systems subject to holonomic constraints

Rodriguez Tsouroukdissian, Adolfo; Basañez Villaluenga, Luis; Colgate, Edward; Faulring, Eric L.
International journal of robotics research
Date of publication: 2010-04
Journal article

• 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

• Nonlinear Bilateral Teleoperation: Stability Analysis

Nuño Ortega, Emmanuel; Basañez Villaluenga, Luis
IEEE International conference on robotics and automation
Date of publication: 2009
Journal article

• Asymptotic Stability of Teleoperators with Variable Time-Delays

Nuño Ortega, Emmanuel; Basañez Villaluenga, Luis; Prada Sarasola, Miguel
IEEE International conference on robotics and automation
Date of publication: 2009
Journal article

• Relational Positioning in Robot Task Specification and Execution.

Defense's date: 2009-07-16
Institute of Industrial and Control Engineering (IOC), Universitat Politècnica de Catalunya
Theses

• Teleoperation

Basañez Villaluenga, Luis; Suarez Feijoo, Raul
Date of publication: 2009
Book chapter

• TELETAREA ROBOTIZADA COOPERATIVA EN RED

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

• 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

• Control of Teleoperators with Time-Delay: A Lyapunov Approach

Nuño Ortega, Emmanuel; Basañez Villaluenga, Luis; Ortega, Romeo
Lecture notes in control and information sciences
Date of publication: 2009
Journal article

• Position Tracking for Non-linear Teleoperators with Variable Time Delay

Nuño Ortega, Emmanuel; Basañez Villaluenga, Luis; Spong, MW
International journal of robotics research
Date of publication: 2009-07
Journal article

• Validation of an Aided Teleoperation Framework for Robotic Tasks

Rodriguez Tsouroukdissian, Adolfo; Basañez Villaluenga, Luis; Nuño Ortega, Emmanuel
40TH INTERNATIONAL SYMPOSIUM ON ROBOTICS
Presentation of work at congresses

• A new proportional controller for onlinear bilateral teoperators

Nuño Ortega, Emmanuel; Basañez Villaluenga, Luis; Barabanov, N
World Congress of the International Federation of Automatic Control
Presentation of work at congresses