Now showing items 1-20 of 75

    • A bilinear formulation for the motion planning of non-holonomic parallel orienting platforms 

      Grosch Obregon, Patrick John; Thomas, Federico (Institute of Electrical and Electronics Engineers (IEEE), 2013)
      Conference report
      Open Access
      This paper deals with the motion planning problem for parallel orienting platforms with one non-holonomic joint and two prismatic actuators which can maneuver to reach any three-degree-of-freedom pose of the moving platform. ...
    • A coordinate-free approach to tracing the coupler curves of pin-jointed linkages 

      Rojas Libreros, Nicolás Enrique; Thomas, Federico (ASME PRESS, 2011)
      Conference report
      Restricted access - publisher's policy
      In general, high-order coupler curves of plane mechanisms cannot be properly traced by standard predictor-corrector algorithms due to drifting problems and the presence of singularities. Instead of focusing on finding ...
    • 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 distance-based formulation of the octahedral manipulator kinematics 

      Rojas Libreros, Nicolás Enrique; Borràs Sol, Júlia; Thomas, Federico (2010)
      Conference report
      Open Access
      In most practical implementations of the Gough-Stewart platform, the octahedral form is either taken as it stands or is approximated. The kinematics of this particular instance of the Gough-Stewart platform, commonly known ...
    • 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 fast branch-and-prune algorithm for the position analysis of spherical mechanisms 

      Shabani, Arya; Sarabandi, Soheil; Porta Pleite, Josep Maria; Thomas, Federico (Springer, 2019)
      Conference report
      Open Access
      Different branch-and-prune schemes can be found in the literature for numerically solving the position analysis of spherical mechanisms. For the prune operation, they all rely on the propagation of motion intervals. They ...
    • A linear relaxation technique for the position analysis of multi-loop linkages 

      Porta Pleite, Josep Maria; Ros Giralt, Lluís; Thomas, Federico (2008)
      External research report
      Open Access
      This report presents a new method able to isolate all configurations that a multi-loop linkage can adopt. We tackle the problem by providing formulation and resolution techniques that fit particularly well together. The ...
    • A linear relaxation technique for the position analysis of multiloop linkages 

      Porta Pleite, Josep Maria; Ros Giralt, Lluís; Thomas, Federico (2009)
      Article
      Open Access
      This paper presents a new method to isolate all configurations that a multiloop linkage can adopt. The problem is tackled by means of formulation and resolution techniques that fit particularly well together. The adopted ...
    • A matrix-based approach to the image moment problem 

      Martínez Bauzà, Judit; Porta Pleite, Josep Maria; Thomas, Federico (2006-11)
      Article
      Open Access
      An image can be seen as an element of a vector space and hence it can be expressed in as a linear combination of the elements of any non necessarily orthogonal basis of this space. After giving a matrix formulation of this ...
    • A new insight into the coupler curves of the RCCC four-bar linkage 

      Thomas, Federico; Pérez Gracia, Alba (Springer, 2017)
      Conference report
      Open Access
      Based on the condition for four points to lie on the unit sphere, derived using Distance Geometry, a new mathematical formulation for the coupler curves of the RCCC linkage is presented. The relevance of this formulation ...
    • A one-motor full-mobility 6-PUS manipulator 

      Grosch Obregon, Patrick John; Gregorio, Raffaele di; Thomas, Federico (Springer, 2010)
      Conference report
      Open Access
      This paper presents the feasibility study of an under-actuated parallel manipulator with 6-PUS topology, destined to handle work-tables in CNC machine tools. The proposed device exploits the fact that, in such an application, ...
    • A reconfigurable 5-DoF 5-SPU parallel platform 

      Borràs Sol, Júlia; Thomas, Federico; Ottaviano, Erika; Ceccarelli, Marco (2009)
      Conference report
      Open Access
      This paper presents a 5-SPU platform whose base leg attachments can be easily reconfigured, statically or dynamically, without altering its singularity locus. This permits to adapt the platform’s geometry to particular ...
    • A reconfigurable asymmetric 3-UPU parallel robot 

      Sarabandi, Soheil; Grosch Obregon, Patrick John; Porta Pleite, Josep Maria; Thomas, Federico (2018)
      Conference report
      Open Access
      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 ...
    • 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 short account of Leonardo Torres' endless spindle 

      Thomas, Federico (2008)
      Article
      Restricted access - publisher's policy
      At the end of the 19th century, several analog machines had been proposed for solving algebraic equations. These machines – based not only on kinematics principles but also on dynamic or hydrostatic balances, electric or ...
    • A space decomposition method for path planning of loop linkages 

      Porta Pleite, Josep Maria; Cortes, Juan; Ros Giralt, Lluís; Thomas, Federico (IEEE, 2007)
      Conference report
      Open Access
      This paper introduces box approximations as a new tool for path planning of closed-loop linkages. Box approximations are finite collections of rectangloids that tightly envelop the robot's free space at a desired resolution. ...
    • A space decomposition method for path planning of loop linkages 

      Porta Pleite, Josep Maria; Cortés, Juan; Ros Giralt, Lluís; Thomas, Federico (2007)
      Conference report
      Open Access
      This paper introduces box approximations as a new tool for path planning of closed-loop linkages. Box approximations are finite collections of rectangloids that tightly envelop the robot's free space at a desired resolution. ...
    • A survey on the computation of quaternions from rotation matrices 

      Sarabandi, Soheil; Thomas, Federico (ASME PRESS, 2019-04-01)
      Article
      Open Access
      The parameterization of rotations is a central topic in many theoretical and applied fields such as rigid body mechanics, multibody dynamics, robotics, spacecraft attitude dynamics, navigation, 3D image processing, computer ...
    • A unified position analysis of the Dixon and the generalized Peaucellier linkages 

      Rojas Libreros, Nicolás Enrique; Dollar, Aaron M.; Thomas, Federico (2015-12-01)
      Article
      Open Access
      This paper shows how, using elementary Distance Geometry, a closure polynomial of degree 8 for the Dixon linkage can be derived without any trigonometric substitution, variable elimination, or artifice to collapse mirror ...
    • A wire-based active tracker 

      Andrade-Cetto, Juan; Thomas, Federico (IEEE, 2008)
      Article
      Open Access
      Wire-based tracking devices are an affordable alternative to costly tracking devices. They consist of a fixed base and a platform, attached to the moving object, connected by six wires whose tension is maintained along the ...