Now showing items 1-20 of 25

    • 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 ...
    • 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 ...
    • 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 ...
    • 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 ...
    • Development of a simulation tool for the kinematic control of a robot 

      Acín Sala, Roger (Universitat Politècnica de Catalunya, 2020-10-21)
      Bachelor thesis
      Open Access
      During the academic years of the Degree, as students we interact with so many subjects and engineering fields. One of the most interesting is the industrial robotics and their role not only in the industry of today, but ...
    • 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 ...