Ara es mostren els items 27-46 de 53

    • Geometric Design Of Symmetric 3-RRS Constrained Parallel Platforms 

      Wolbrecht, Eric; Su, Hai Jun; Pérez Gracia, Alba; McCarthy, John Michael (American Society of Mechanical Engineers (ASME), 2004)
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      The paper presents the kinematic synthesis of a symmetric parallel platform supported by three RRS serial chains. The dimensional synthesis of this three degree-of-freedom system is obtained using design equations for each ...
    • Grasping unknown objects in clutter by superquadric representation 

      Makhal, Abhijit; Thomas, Federico; Pérez Gracia, Alba (Institute of Electrical and Electronics Engineers (IEEE), 2018)
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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 ...
    • Humanoid synthesis using clifford algebra 

      Villa Uriol, Mari Cruz; Pérez Gracia, Alba; Kuester, Falco (IEEE, 2006)
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      One of the challenges in the simulation of human motion, either applied to humanoid robots or avatars in virtual environments, is to design a kinematics structure and a set of joint trajectories that move a robot or avatar ...
    • In-Hand Manipulative Synthesis Using Velocity Subspaces 

      Hassanzadeh, Neda; Gosh, Shramana; Robson, Nina; Pérez Gracia, Alba (Springer, 2016)
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      The kinematic design of robots for tasks involving positions and its derivatives has been explored in the past in order to shape the trajectory of the robot at a given set of points. This approach has been successful for ...
    • Inverse Kinematics Using a Converging Paths Algorithm 

      Heidari, Omid; Pérez Gracia, Alba (Springer Nature, 2020)
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      This article presents a numerical method for the inverse kinematics of serial chains by utilizing dual quaternion formulation of the robot kinematics within a converging paths algorithm. The method is inspired by iterative ...
    • Kinematic synthesis for smart hand prosthetics 

      Duraisamy, Karthikeyan; Isebor, Obiajulu; Pérez Gracia, Alba; Schoen, Marco P.; Naidu, Desineni Subbaram (IEEE Press. Institute of Electrical and Electronics Engineers, 2006)
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      The dream of a bionic replacement appendage is becoming reality through the use of mechatronic prostheses that utilize the body’s myoelectric signals. This paper presents a process to accurately capture the motion of ...
    • Kinematic synthesis of multi-fingered robotic hands for finite and infinitesimal tasks 

      Simó Serra, Edgar; Pérez Gracia, Alba; Moon, Hyosang; Robson, Nina (Springer, 2012)
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      In this paper we present a novel method of designing multi-fingered robotic hands using tasks composed of both finite and infinitesimal motion. The method is based on representing the robotic hands as a kinematic chain ...
    • Link-based Performance Optimization of Spatial Mechanisms 

      Yihun, Yimesker; Bosworth, Kenneth; Pérez Gracia, Alba (2014-12)
      Article
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      In the design of spatial linkages, the finite-position kinematics is fully specified by the position of the joint axes, i.e., a set of lines in space. However, most of the tasks have additional requirements regarding motion ...
    • Link-based performance optimization of spatial mechanisms 

      Yihun, Yimesker; Bosworth, Kenneth; Pérez Gracia, Alba (American Society of Mechanical Engineers (ASME), 2013)
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      In the design of spatial linkages, the finite-position kinematics is fully specified by the position of the joints in space. However, most of the tasks have additional requirements regarding motion smoothness, obstacle ...
    • Mixed Position and Twist Space Synthesis of 3R Chains 

      Hassanzadeh, Neda; Pérez Gracia, Alba (MDPI AG, 2022)
      Article
      Accés obert
      Mixed-position kinematic synthesis is used to not only reach a certain number of precision positions, but also impose certain instantaneous motion conditions at those positions. In the traditional approach, one end-effector ...
    • On Cayley's factorization of 4D rotations and applications 

      Pérez Gracia, Alba; Thomas, Federico (2017-03-01)
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      A 4D rotation can be decomposed into a left- and a right-isoclinic rotation. This decomposition, known as Cayley’s factorization of 4D rotations, can be performed using the Elfrinkhof–Rosen method. In this paper, we present ...
    • 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
      Accés obert
      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 ...
    • On Cayley’s Factorization of 3D Rotations and Applications 

      Thomas, Federico; Pérez Gracia, Alba (Facultat d'Informàtica de Barcelona (UPC), 2015)
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      A 4D rotation can be decomposed into a left- and a right-isoclinic rotation. This decomposition, known as Cayley’s factorization of 4D rotations, can be performed using the Elfrinkhof–Rosen method. In this paper, we present ...
    • Quantification of Upper-body Synergies: a Case Comparison for Stroke and non-Stroke Victims 

      Roylance, John; Heidari, Omid; Pérez Gracia, Alba; Kendall, Eydie (2016)
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      Motion synergies are principal components of the movement, obtained as combinations of joint degrees of freedom, that account for common postures of the human body. These synergies are usually obtained by capturing the ...
    • Quaternions and Clifford Algebras 

      Pérez Gracia, Alba (Springer, 2021)
      Capítol de llibre
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      Quaternions are a type of hypercomplex numbers. Unit quaternions, which describe rotations, were called versors by Hamilton. The concept of versor can be generalized as the product of invertible vectors in the Clifford ...
    • Single degree-of-freedom exoskeleton mechanism design for finger rehabilitation 

      Wolbrecht, Eric T.; Reinkensmeyer, David J.; Pérez Gracia, Alba (2011)
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      This paper presents the kinematic design of a single degree-of-freedom exoskeleton mechanism: a planar eight-bar mechanism for finger curling. The mechanism is part of a fingerthumb robotic device for hand therapy that ...
    • Singularity Design for RRSS Mechanisms 

      Deemyad, Taher; Heidari, Omid; Pérez Gracia, Alba (2020)
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      This paper explores the design of RRSS mechanisms with specified singular positions. The ultimate goal is to find an SS chain to couple a previously synthesized RR chain and to force the mechanism to become singular at ...
    • Singularity-free computation of quaternions from rotation matrices in E4 and E3 

      Sarabandi, Soheil; Pérez Gracia, Alba; Thomas, Federico (2018)
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      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 ...
    • Sizing a Serial Chain to Fit a Task Trajectory Using Clifford Algebra Exponentials 

      Pérez Gracia, Alba; McCarthy, John Michael (2005)
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      In this paper we formulate the “generalized inverse kinematics problem” for a spatial serial chain, where the goal is to determine values for structural parameters as well as for the joint parameters. The kinematics equations ...
    • Solvable Multi-Fingered Hands for Exact Kinematic Synthesis 

      Makhal, Abhijit; Pérez Gracia, Alba (Springer, 2014)
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      Multi-fingered hands are kinematic chains with a tree topology, that is, with a set of common joints that span several branches and end-effectors. When performing dimensional kinematic synthesis with simultaneous tasks for ...