Examinando por Materia "Kinematics"
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Ítem Analytical method for the kinetostatic analysis of the second-class RRR assur group allowing for friction in the kinematic pairs(Springer Berlin Heidelberg, 2010-07-01) Durango, S.; Calle, G.; Ruiz, O.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEThe calculation of forces in the kinematic pairs of mechanisms by inverse dynamics is usually performed without friction considerations. In practice, when examination of articulated mechanisms takes into account friction, the solution of the inverse dynamics results in a complex procedure. If a modular approach for the inverse dynamics is used, then exact solutions are available, but not necessarily are practical. For example, the analytical solution for a second-class first-type Assur group is a 16th degree equation. Previous researches proposed an approximated but practical (graphical) method to calculate the forces on the kinematic pairs taking into account the friction forces. In this article, an analytical interpretation of the Artobolevski approximated method is developed for the second-class Assur group with three rotational pairs. The final results for the reactions calculated with the implemented method present a good approximation with respect to the graphical solution. Future work should consider friction forces not only in second-class groups with rotational joints, but also in second-class groups with prismatic joints and high-class Assur groups. Copyright © 2010 by ABCM.Ítem Caracterización de la cinemática y cálculo de paleo-tensores de esfuerzo para el conjunto principal de fallas en el Valle de Aburrá, implicaciones tectónicas(Universidad EAFIT, 2017) Mariño Arias, Óscar Mario; Duque Trujillo, José FernandoThe tectonic evolution and the opening process of the Aburrá Valley, has been studied and discussed for several decades -- However, the factors and the kinematics that led to the opening of this depression are still under debate -- Recent studies suggests that the configuration of the Aburrá Valley is product of the movement of fault systems along the basin margins, displacement of blocks towards their axial zone, and formation of a "pull- apart" basin -- Nevertheless, to date, a concrete kinematic model for its evolution and development have not been developed -- The present work, through a population análisis of faults and fault-slip inversion using the right-dihedra method, proposes that the Aburrá Valley was formed as a pull-apart basin inside a right-lateral shear zone, product of a main stress tensor acting NE-SWÍtem Comment on ‘Petrotectonic characteristics, geochemistry, and U–Pb geochronology of Jurassic plutons in the Upper Magdalena Valley-Colombia: Implications on the evolution of magmatic arcs in the NW Andes’ by Rodríguez et al. (2018)(PERGAMON-ELSEVIER SCIENCE LTD, 2019-11-01) Bustamante C.; Cardona A.; Bustamante A.; Vanegas J.; Bustamante C.; Cardona A.; Bustamante A.; Vanegas J.; Universidad EAFIT. Departamento de Ciencias; Geología Ambiental y Tectónica[No abstract available]Ítem Computational Geometry in Medical Applications(Universidad EAFIT, 2016) Cortés Acosta, Camilo Andrés; Ruíz Salguero, Óscar Eduardo; Flórez Esnal, JuliánÍtem Experiment design in compliant mechanisms and kinematic identification of parallel mechanisms(Universidad EAFIT, 2010) Restrepo Arango, David; Ruíz Salguero, Oscar EduardoThis article discusses a procedure for force-displacement modeling compliant mechanisms by using a design of computer experiments methodology -- This approach produces a force-displacement meta-model that is suited for real-time control of compliant mechanisms -- The term meta-model is used to represent a simplified and efficient mathematical model of unknown phenomena -- The meta-modeling of compliant mechanisms is performed from virtual experiments based on factorial- and space-filling design of experiments -- The procedure is used to model the quasi-static behavior of the HexFlex compliant mechanism -- The HexFlex is a parallel compliant mechanism for nano-manipulation that allows six degrees of freedom of its moving stage -- The meta-model of the HexFlex is calculated from experiments with the Finite Element Method (FEM) -- The obtained meta-model for the HexFlex is linear for the range of movement of the mechanism -- The accuracy of the meta-model was calculated conducting a set of computer experiments with random uniform distribution of the input forces -- Three criteria were calculated in each displacement direction (x, y, z, θx, θy, θz) comparing the meta-model prediction with respect to the results of the virtual experiments: 1. maximum of the absolute value of the error, 2. relative error, and 3. root mean square error -- The maximum errors were founded adequate with respect to demanding manufacturing tolerances (absolute errors) and lower than errors reported by other authors (relative errors)Ítem Finite Element Modeling of Composite Materials using Kinematic Constraints(Universidad EAFIT, 2009-12-01) E. Ruiz, Oscar; Barschke, Merlin; Uribe, David; Jensen, Jens; López, Carlos; Universidad EAFITÍtem Force-Displacement Model of Compliant Mechanisms using Assur Sub-Chains(2011-06) Durango, S.; Correa, J.; Ruíz, O.; Aristizábal, M.; Restrepo-Giraldo, J.; Achiche, S.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEThis article develops a modular procedure to perform force-displacement modeling of planar flexurebased compliant mechanisms (CMs) -- The procedure is mostly suitable for planar lumped CMs -- To achieve the position analysis of CMs requires: (i) to implement the kinematic analysis as for ordinary mechanisms, (ii) to solve equilibrium problem by means of an static analysis and (iii) to model the flexures behavior through a deflection analysis -- The novel contribution of this article relies on the fact that a division strategy of the CM into Assur subchainsm is implemented, so that any CM subjected to such disaggregation can be accurately modeled -- For this purpose a mathematical model for leaf-spring flexure type is presented and used through this paper -- However any other flexure model can be used instead -- To support the technique, a three Degrees–Of–Freedom (3-DOF) flexure-based parallel mechanism is used as case study -- Results are compared to a Finite Element Analysis (FEA)Ítem Graph-based structural analysis of planar mechanisms(Springer Netherlands, 2017-01-01) Durango, S.; Correa, J.; Ruiz, O.E.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEKinematic structure of planar mechanisms addresses the study of attributes determined exclusively by the joining pattern among the links forming a mechanism. The system group classification is central to the kinematic structure and consists of determining a sequence of kinematically and statically independent-simple chains which represent a modular basis for the kinematics and force analysis of the mechanism. This article presents a novel graph-based algorithm for structural analysis of planar mechanisms with closed-loop kinematic structure which determines a sequence of modules (Assur groups) representing the topology of the mechanism. The computational complexity analysis and proof of correctness of the implemented algorithm are provided. A case study is presented to illustrate the results of the devised method. © 2016, Springer Science+Business Media Dordrecht.Ítem Kinematic identification of parallel mechanisms by a divide and conquer strategy(2010) Durango, Sebastián; Restrepo, David; Ruíz, Óscar; Restrepo-Giraldo, John; Achiche, Sofiane; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEThis paper presents a Divide and Conquer strategy to estimate the kinematic parameters of parallel symmetrical mechanisms -- The Divide and Conquer kinematic identification is designed and performed independently for each leg of the mechanism -- The estimation of the kinematic parameters is performed using the inverse calibration method -- The identification poses are selected optimizing the observability of the kinematic parameters from a Jacobian identification matrix -- With respect to traditional identification methods the main advantages of the proposed Divide and Conquer kinematic identification strategy are: (i) reduction of the kinematic identification computational costs, (ii) improvement of the numerical efficiency of the kinematic identification algorithm and, (iii) improvement of the kinematic identification results -- The contributions of the paper are: (i) The formalization of the inverse calibration method as the Divide and Conquer strategy for the kinematic identification of parallel symmetrical mechanisms and, (ii) a new kinematic identification protocol based on the Divide and Conquer strategy -- As an application of the proposed kinematic identification protocol the identification of a planar 5R symmetrical mechanism is simulated -- The performance of the calibrated mechanism is evaluated by updating the kinematic model with the estimated parameters and developing simulationsÍtem Kinematic identification of parallel mechanisms by a divide and conquer strategy(INSTICC-INST SYST TECHNOLOGIES INFORMATION CONTROL & COMMUNICATION, 2010-01-01) Durango S.; Externo - Escuela - Ingeniería; Ruiz O.; Restrepo-Giraldo J.; Achiche S.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEThis paper presents a Divide and Conquer strategy to estimate the kinematic parameters of parallel symmetrical mechanisms. The Divide and Conquer kinematic identification is designed and performed independently for each leg of the mechanism. The estimation of the kinematic parameters is performed using the inverse calibration method. The identification poses are selected optimizing the observability of the kinematic parameters from a Jacobian identification matrix. With respect to traditional identification methods the main advantages of the proposed Divide and Conquer kinematic identification strategy are: (i) reduction of the kinematic identification computational costs, (ii) improvement of the numerical efficiency of the kinematic identification algorithm and, (iii) improvement of the kinematic identification results. The contributions of the paper are: (i) The formalization of the inverse calibration method as the Divide and Conquer strategy for the kinematic identification of parallel symmetrical mechanisms and, (ii) a new kinematic identification protocol based on the Divide and Conquer strategy. As an application of the proposed kinematic identification protocol the identification of a planar 5R symmetrical mechanism is simulated. The performance of the calibrated mechanism is evaluated by updating the kinematic model with the estimated parameters and developing simulations.Ítem Symmetrical Observability of Kinematic Parameters in Symmetrical Parallel Mechanisms(Editora Edgard Blücher Ltda., 2014-05) Durango, S.; Restrepo, D.; Ruíz, O.; Restrepo-Giraldo, J.; Achiche, S.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEThis article presents an application of symmetry group theory in kinematic identification of parallel mechanisms of nlegs legs -- Kinematic Identification implies the estimation of the actual geometrical parameters (as opposed to nominal ones) of a physical mechanism -- For a symmetric mechanism, KI requires configuring sets of leg positions with symmetrical observability – This article presents as main contributions: (i) a conjecture that allows mapping the symmetries of the mechanism into the active-joint workspace, (ii) a set of necessary conditions to express leg parameters in coordinate systems which allow symmetrical observability, and (iii) a procedure for exploiting symmetries in pose selection for kinematic identification of symmetrical parallel mechanisms -- For the kinematic identification itself, we adopt a divide-and-conquer (DC) identification protocol -discussed by us in another publication- in which each leg of the mechanism is independently identified by using the inverse calibration method -- In this article we emphasize how to exploit the symmetries existent in (nlegs − 1) legs of the parallel mechanism allowing to apply to other legs the symmetry-transformed sample protocol used for the kinematic identification of a reference leg -- The symmetrical observability of sets of leg parameters allows to reduce the costs of the pose selection procedure by a factor of (1/nlegs) compared to a complete DC procedure in which the poses of each leg are selected independently -- The pose selection is carried out only for the reference leg -- For the (nlegs−1) remaining legs the poses are dictated by symmetry operations performed onto the poses of the reference leg -- An application of the symmetrical observability is presented through the simulated kinematic identification of a 3RRR symmetrical parallel mechanismÍtem Using Gröbner Bases in Kinematic Analysis of Mechanisms(Birkhäuser Verlag, 1996) Ruíz, Óscar E.; Ferreira, Placid M.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE