Enviaments recents

  • A singularity-robust LQR controller for parallel robots 

    Bordalba Llaberia, Ricard; Porta Pleite, Josep Maria; Ros Giralt, Lluís (Institute of Electrical and Electronics Engineers (IEEE), 2018)
    Text en actes de congrés
    Accés obert
    Parallel robots exhibit the so-called forward singularities, which complicate substantially the planning and control of their motions. Often, such complications are circumvented by restricting the motions to singularity-free ...
  • The forward kinematics of doubly-planar Gough-Stewart platforms and the position analysis of strips of tetrahedra 

    Porta Pleite, Josep Maria; Thomas, Federico (Springer, 2018)
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    A strip of tetrahedra is a tetrahedron-tetrahedron truss where any tetrahedron has two neighbors except those in the extremes which have only one. The problem of finding all the possible lengths for an edge in the strip ...
  • Grasping unknown objects in clutter by superquadric representation 

    Makhal, Abhijit; Thomas, Federico; Pérez Gracia, Alba (Institute of Electrical and Electronics Engineers (IEEE), 2018)
    Text en actes de congrés
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    In this paper, a quick and efficient method is presented for grasping unknown objects in clutter. The grasping method relies on real-time superquadric (SQ) representation of partial view objects and incomplete object ...
  • Yet another approach to the Gough-Stewart platform forward kinematics 

    Porta Pleite, Josep Maria; Thomas, Federico (2018)
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    The forward kinematics of the Gough-Stewart platform, and their simplified versions in which some leg endpoints coalesce, has been typically solved using variable elimination methods. In this paper, we cast doubts on whether ...
  • Randomized planning of dynamic motions avoiding forward singularities 

    Bordalba Llaberia, Ricard; Ros Giralt, Lluís; Porta Pleite, Josep Maria (Springer International Publishing, 2018)
    Text en actes de congrés
    Accés obert
    Forward singularities, also known as direct, or actuator singularities, cause many problems to the planning and control of robot motions. They yield position errors and rigidity losses of the robot, and generate unbounded ...
  • Randomized kinodynamic planning for constrained systems 

    Bordalba Llaberia, Ricard; Ros Giralt, Lluís; Porta Pleite, Josep Maria (Institute of Electrical and Electronics Engineers (IEEE), 2018)
    Text en actes de congrés
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    Kinodynamic RRT planners are considered to be general tools for effectively finding feasible trajectories for high-dimensional dynamical systems. However, they struggle when holonomic constraints are present in the system, ...
  • Accurate computation of quaternions from rotation matrices 

    Sarabandi, Soheil; Thomas, Federico (Springer International Publishing, 2018)
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    The main non-singular alternative to 3×3 proper orthogonal matrices, for representing rotations in R3, is quaternions. Thus, it is important to have reliable methods to pass from one representation to the other. While ...
  • A reconfigurable asymmetric 3-UPU parallel robot 

    Sarabandi, Soheil; Grosch Obregon, Patrick John; Porta Pleite, Josep Maria; Thomas, Federico (2018)
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    Parallel robots with three UPU legs have received a lot of attention due to the possibility of assembling these legs so that the robot performs either a pure translational or a pure rotational motion. Nevertheless, some ...
  • Randomized kinodynamic planning for cable-suspended parallel robots 

    Bordalba Llaberia, Ricard; Porta Pleite, Josep Maria; Ros Giralt, Lluís (Springer, 2017)
    Text en actes de congrés
    Accés obert
    This paper proposes the use of a randomized kinodynamic planning technique to synthesize dynamic motions for cable-suspended parallel robots. Given two mechanical states of the robot, both with a prescribed position and ...
  • Closure polynomials for strips of tetrahedra 

    Thomas, Federico; Porta Pleite, Josep Maria (Springer, 2016)
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    A tetrahedral strip is a tetrahedron-tetrahedron truss where any tetrahedron has two neighbors except those in the extremes which have only one. Unless any of the tetrahedra degenerate, such a truss is rigid. In this case, ...
  • On quartically-solvable robots 

    Rojas Librero, Nicolás Enrique; Borràs Sol, Júlia; Thomas, Federico (Institute of Electrical and Electronics Engineers (IEEE), 2015)
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    This paper presents a first attempt at a unified kinematics analysis of all serial and parallel solvable robots, that is, robots whose position analysis can be carried out without relying on numerical methods. The efforts ...
  • Distance bound smoothing under orientation constraints 

    Rull Sanahuja, Aleix; Porta Pleite, Josep Maria; Thomas, Federico (Institute of Electrical and Electronics Engineers (IEEE), 2015)
    Text en actes de congrés
    Accés obert
    Distance Bound Smoothing (DBS) is a basic operation originally developed in Computational Chemistry to determine point configurations that are within certain pairwise ranges of distances. This operation consist in the ...

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