Now showing items 1-20 of 24

  • A distance geometry approach to the singularity analysis of 3R robots 

    Thomas, Federico (ASME PRESS, 2015)
    Article
    Restricted access - publisher's policy
    This paper shows how the computation of the singularity locus of a 3R robot can be reduced to the analysis of the relative position of two coplanar ellipses. Since the relative position of two conics is a projective ...
  • A family of quadratically-solvable 5-SPU parallel robots 

    Borràs Sol, Júlia; Thomas, Federico; Torras, Carme (2010)
    Conference report
    Open Access
    A 5-SPU robot with collinear universal joints is well suited to handling an axisymmetric tool, since it has 5 controllable DoFs and the remaining one is a free rotation around the tool. The kinematics of such a robot having ...
  • Analysing the singularities of 6-SPS parallel robots using virtual legs 

    Borràs Sol, Júlia; Thomas, Federico; Torras, Carme (LIRMM, 2008)
    Conference report
    Open Access
    A virtual leg in a 6-SPS parallel robot is defined as a leg whose length is determined by the lengths of a subset of the actual legs of the robot. This necessarily implies that this subset of legs defines a rigid subassembly. ...
  • Approaching dual quaternions from matrix algebra 

    Thomas, Federico (2014)
    Article
    Open Access
    Dual quaternions give a neat and succinct way to encapsulate both translations and rotations into a unified representation that can easily be concatenated and interpolated. Unfortunately, the combination of quaternions and ...
  • Architecture singularities in flagged parallel manipulators 

    Borràs Sol, Júlia; Thomas, Federico; Torras, Carme (IEEE, 2008)
    Conference report
    Open Access
    Flagged manipulators are of interest because they are the only Stewart-Gough platforms for which a cell decomposition of their singularity loci is available. Here we show that the known family of such manipulators can be ...
  • A robust forward kinematics analysis of 3-RPR planar platforms 

    Rojas Libreros, Nicolás Enrique; Thomas, Federico (Springer Verlag, 2010)
    Conference report
    Open Access
    The standard forward kinematics analysis of 3-RPR planar parallel platforms boils down to computing the roots of a sextic polynomial. There are many different ways to obtain this polynomial but all of them include exceptions ...
  • A wrench-sensitive touch pad based on a parallel structure 

    Frigola Alcalde, Roger; Ros Giralt, Lluís; Roure Fernández, Francisco; Thomas, Federico (IEEE, 2008)
    Conference report
    Open Access
    Many different robotic in-parallel structures have been conceived as six-component force sensors. In general, they perform well for most applications but, when accuracy is a must, two main limitations arise. First, in most ...
  • Closed-form solution to the position analysis of Watt–Baranov trusses using the bilateration method 

    Rojas Libreros, Nicolás Enrique; Thomas, Federico (ASME PRESS, 2011)
    Article
    Restricted access - publisher's policy
    The exact position analysis of a planar mechanism reduces to compute the roots of its characteristic polynomial. Obtaining this polynomial almost invariably involves, as a first step, obtaining a system of equations derived ...
  • Direct position analysis of a large family of spherical and planar parallel manipulators with four loops 

    Borràs Sol, Júlia; Gregorio, Raffaele di (LIRMM, 2008)
    Conference report
    Open Access
    The direct position analysis (DPA) of a manipulator is the computation of the end-effector poses (positions and orientations) compatible with assigned values of the actuated-joint variables. Assigning the actuated-joint ...
  • Exploiting single-cycle symmetries in branch-and-prune algorithms 

    Ruiz de Angulo García, Vicente; Torras, Carme (Springer Verlag, 2007)
    Part of book or chapter of book
    Open Access
    As a first attempt to exploit symmetries in continuous con- straint problems, we focus on permutations of the variables consisting of one single cycle. We propose a procedure that takes advantage of these symmetries by ...
  • Generation of under-actuated parallel robots with non-holonomic joints and kinetostatic analysis of a case-study 

    Grosch Obregon, Patrick John; Gregorio, Raffaele di; Thomas, Federico (2009)
    Conference report
    Restricted access - publisher's policy
    It will be shown how to generate under-actuated manipulators by substituting non-holonomic spherical pairs (nS pairs) for (holonomic) spherical pairs (S pairs) in fully-parallel manipulators (FPMs). Through this pair ...
  • Geometric path planning without maneuvers for nonholonomic parallel orienting robots 

    Grosch Obregon, Patrick John; Thomas, Federico (Institute of Electrical and Electronics Engineers (IEEE), 2016-07)
    Article
    Open Access
    Current geometric path planners for nonholonomic parallel orienting robots generate maneuvers consisting of a sequence of moves connected by zero-velocity points. The need for these maneuvers restrains the use of this kind ...
  • IK-FA, a new heuristic inverse kinematics solver using firefly algorithm 

    Rokbani, Nizar; Casals Gelpi, Alicia; Alimi, Adel M. (Springer, 2015-11-27)
    Part of book or chapter of book
    Open Access
    In this paper, a heuristic method based on Firefly Algorithm is proposed for inverse kinematics problems in articulated robotics. The proposal is called, IK-FA. Solving inverse kinematics, IK, consists in finding a set of ...
  • Implementación de un control fuzzy para el control cinemático directo en un robot manipulador 

    Tibaduiza Burgos, Diego Alexander; Amaya, I.; Rodríguez, Silvia; Mejía, N.; Flórez, Mario (2012-12)
    Article
    Open Access
    En este artículo se muestra el desarrollo e implementación de la lógica difusa como herramienta de control de posición para cada una de las articulaciones de un robot tipo PUMA. Se hace una descripción general del robot ...
  • JXTA-overlay P2P platform and its application for robot control 

    Ogata, Yuichi; Spaho, Evjola; Matsuo, Keita; Barolli, Leonard; Arnedo Moreno, Joan; Xhafa Xhafa, Fatos (Institute of Electrical and Electronics Engineers (IEEE), 2010)
    Conference report
    Open Access
    The design of an efficient collaborative multirobot framework that ensures the autonomy and the individual requirements of the involved robots is a very challenging task. This requires designing an efficient platform for ...
  • Kinematics of line-plane subassemblies in Stewart platforms 

    Borràs Sol, Júlia; Thomas, Federico (IEEE, 2009-05-31)
    Conference report
    Open Access
    When the attachments of five legs in a Stewart platform are collinear on one side and coplanar on the other, the platform is said to contain a line-plane subassembly. This paper is devoted to the kinematics analysis of ...
  • Optimal design of a 6-DOF 4-4 parallel manipulator with uncoupled singularities 

    Borràs Sol, Júlia; Ottaviano, Erika; Ceccarelli, Marco; Thomas, Federico (Asociación Española de Ingeniería Mecánica, 2008)
    Conference report
    Open Access
    A 6-DOF 4-4 parallel manipulator is presented. Its forward kinematics can be solved by a sequence of three trilaterations and, as a consequence, its singularities can be described in geometric terms as the degeneration of ...
  • Polynomial solution to the position analysis of two Assur kinematic chains with four loops and the same topology 

    Borràs Sol, Júlia; Gregorio, Raffaele di (ASME PRESS, 2009)
    Article
    Restricted access - publisher's policy
    The direct position analysis (DPA) of a manipulator is the computation of the end-effector poses (positions and orientations) compatible with assigned values of the actuated-joint variables. Assigning the actuated-joint ...
  • Sharpening haptic inputs for teaching a manipulation skill to a robot 

    Rozo Castañeda, Leonel; Jimenez Schlegl, Pablo; Torras, Carme (2010)
    Conference report
    Open Access
    Gaussian mixtures-based learning algorithms are suitable strategies for trajectory learning and skill acquisition, in the context of programming by demonstration (PbD). Input streams other than visual information, as used ...
  • Slave architecture for the Robonova MR-C3024 using the HMI protocol 

    Simó Serra, Edgar; Pegueroles Queralt, Jordi (2010)
    External research report
    Open Access
    The goal of the project is to develop a new rmware for the servo control board Hitec MR- C3024 [8] to improve its speci cations. This board will be used to control the movement of a humanoid robot, driven by digital ...