Now showing items 1-10 of 10

    • 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 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 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 ...
    • Accurate computation of quaternions from rotation matrices 

      Sarabandi, Soheil; Thomas, Federico (Springer International Publishing, 2018)
      Conference report
      Open Access
      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 ...
    • Approximating displacements in R^3 by rotations in R^4 and its application to pointcloud registration 

      Sarabandi, Soheil; Thomas, Federico (Institute of Electrical and Electronics Engineers (IEEE), 2022)
      Article
      Open Access
      No proper norm exists to measure the distance between two object poses essentially because a general pose is defined by a rotation and a translation, and thus it involves magnitudes with different units. As a means to solve ...
    • Hand-eye calibration made easy through a closed-form two-stage method 

      Sarabandi, Soheil; Porta Pleite, Josep Maria; Thomas, Federico (Institute of Electrical and Electronics Engineers (IEEE), 2022)
      Article
      Open Access
      An analysis of the existing hand-eye calibration methods reveals that most of them are far from trivial. And, what is worse, their intrinsic complexity makes it difficult to elucidate under which circumstances they fail ...
    • On Cayley's factorization with an application to the orthonormalization of noisy rotation matrices 

      Sarabandi, Soheil; Pérez Gracia, Alba; Thomas, Federico (2019-05-09)
      Article
      Open Access
      A real orthogonal matrix representing a rotation in four dimensions can be decomposed into the commutative product of a left- and a right-isoclinic rotation matrix. This operation, known as Cayley's factorization, directly ...
    • Singularity-free computation of quaternions from rotation matrices in E4 and E3 

      Sarabandi, Soheil; Pérez Gracia, Alba; Thomas, Federico (2018)
      Conference report
      Open Access
      A real orthogonal matrix representing a rotation in E4 can be decomposed into the commutative product of a left-isoclinic and a right-isoclinic rotation matrix. The double quaternion representation of rotations in E4 follows ...
    • Solving the nearest rotation matrix problem in three and four dimensions with applications in robotics 

      Sarabandi, Soheil (Universitat Politècnica de Catalunya, 2021-04-27)
      Doctoral thesis
      Open Access
      Since the map from quaternions to rotation matrices is a 2-to-1 covering map, this map cannot be smoothly inverted. As a consequence, it is sometimes erroneously assumed that all inversions should necessarily contain ...
    • Yet a better closed-form formula for the 3D nearest rotation matrix problem 

      Wu, Jin; Sarabandi, Soheil; Porta Pleite, Josep Maria; Liu, Ming; Thomas, Federico (2021)
      Research report
      Open Access
      This technical report complements the results recently presented in [1] showing that they can be extended to define an efficient and robust method to determine the rotation matrix nearest to an arbitrary 3 × 3 matrix. This ...