Examinando por Autor "Restrepo, David"

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    Ítem
    Design of computer experiments applied to modeling of compliant mechanisms for real-time control
    (SPRINGER, 2013-07-01) Acosta, Diego A.; Restrepo, David; Durango, Sebastian; Ruiz, Oscar E.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de Procesos
    This article discusses the use of design of computer experiments (DOCE) (i.e., experiments run with a computer model to find how a set of inputs affects a set of outputs) to obtain a force-displacement meta-model (i.e., a mathematical equation that summarizes and aids in analyzing the input-output data of a DOCE) of compliant mechanisms (CMs). The procedure discussed produces a force-displacement meta-model, or closed analytic vector function, that aims to control CMs in real-time. In our work, the factorial and space-filling DOCE meta-model of CMs is supported by finite element analysis (FEA). The protocol discussed is used to model the HexFlex mechanism functioning under quasi-static conditions. The HexFlex is a parallel CM for nano-manipulation that allows six degrees of freedom (x, y, z, ? x, ? y, ? z ) of its moving platform. In the multi-linear model fit of the HexFlex, the products or interactions proved to be negligible, yielding a linear model (i.e., linear in the inputs) for the operating range. The accuracy of the meta-model was calculated by conducting a set of computer experiments with random uniform distribution of the input forces. Three error criteria were recorded comparing the meta-model prediction with respect to the results of the FEA experiments by determining: (1) maximum of the absolute value of the error, (2) relative error, and (3) root mean square error. The maximum errors of our model are lower than high-precision manufacturing tolerances and are also lower than those reported by other researchers who have tried to fit meta-models to the HexFlex mechanism. © 2012 Springer-Verlag London Limited.
  • No hay miniatura disponible
    Ítem
    Design of computer experiments applied to modeling of compliant mechanisms for real-time control
    (SPRINGER, 2013-07-01) Acosta, Diego A.; Restrepo, David; Durango, Sebastian; Ruiz, Oscar E.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
    This article discusses the use of design of computer experiments (DOCE) (i.e., experiments run with a computer model to find how a set of inputs affects a set of outputs) to obtain a force-displacement meta-model (i.e., a mathematical equation that summarizes and aids in analyzing the input-output data of a DOCE) of compliant mechanisms (CMs). The procedure discussed produces a force-displacement meta-model, or closed analytic vector function, that aims to control CMs in real-time. In our work, the factorial and space-filling DOCE meta-model of CMs is supported by finite element analysis (FEA). The protocol discussed is used to model the HexFlex mechanism functioning under quasi-static conditions. The HexFlex is a parallel CM for nano-manipulation that allows six degrees of freedom (x, y, z, ? x, ? y, ? z ) of its moving platform. In the multi-linear model fit of the HexFlex, the products or interactions proved to be negligible, yielding a linear model (i.e., linear in the inputs) for the operating range. The accuracy of the meta-model was calculated by conducting a set of computer experiments with random uniform distribution of the input forces. Three error criteria were recorded comparing the meta-model prediction with respect to the results of the FEA experiments by determining: (1) maximum of the absolute value of the error, (2) relative error, and (3) root mean square error. The maximum errors of our model are lower than high-precision manufacturing tolerances and are also lower than those reported by other researchers who have tried to fit meta-models to the HexFlex mechanism. © 2012 Springer-Verlag London Limited.
  • No hay miniatura disponible
    Ítem
    Design of computer experiments applied to modeling of compliant mechanisms for real-time control
    (Springer London, 2013-07) Acosta, Diego A.; Restrepo, David; Durango, Sebastián; Ruíz, Óscar E.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
    This article discusses the use of design of computer experiments (DOCE) (i.e., experiments run with a computer model to find how a set of inputs affects a set of outputs) to obtain a force–displacement meta-model (i.e., a mathematical equation that summarizes and aids in analyz-ing the input–output data of a DOCE) of compliant mechanisms (CMs) -- The procedure discussed produces a force–displacement meta-model, or closed analytic vector function, that aims to control CMs in real-time -- In our work, the factorial and space-filling DOCE meta-model of CMs is supported by finite element analysis (FEA) -- The protocol discussed is used to model the HexFlex mechanism functioning under quasi-static conditions -- The HexFlex is a parallel CM for nano-manipulation that allows six degrees of freedom (x, y, z, hx, hy, hz) of its moving platform -- In the multi-linear model fit of the HexFlex, the products or inter-actions proved to be negligible, yielding a linear model (i.e.,linear in the inputs) for the operating range -- The accuracy of the meta-model was calculated by conducting a set of computer experiments with random uniform distribution of the input forces -- Three error criteria were recorded comparing the meta-model prediction with respect to the results of the FEA experiments by determining: (1) maximum of the absolute value of the error, (2) relative error, and (3) root mean square error -- The maximum errors of our model are lower than high-precision manufacturing tolerances and are also lower than those reported by other researchers who have tried to fit meta-models to the HexFlex mechanism
  • No hay miniatura disponible
    Ítem
    HexFlex Mechanism Modeling by Design of Computer Experiments
    (Springer London, 2010-04) Acosta, Diego; Restrepo, David; Ruíz, Oscar; Durango, Sebastián; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
    Compliant mechanisms are an instance of mechanical devices designed to transfer or transmit motion, force, or energy from specified input ports to output ports by elastic deformation of at least one of its members -- The main advantage of compliant mechanisms with respect to traditional rigid-link mechanism is that fewer parts, fewer assembly process and no lubrication are required -- The HexFlex is a parallel compliant mechanism for nano-manipulating that allows six degrees of freedom of its moving stage -- This mechanism was designed for high precisión an repeatability -- This article presents a methodology to model compliant mechanisms behavior under quasi-static conditions using computer experiments, reducing costs of experimentation of product development -- The methodology is used to establish a mathematical model that relates the actuator forces at the input ports with the position and orientation the end-effector stage of the Hexflex -- This mathematical model has direct application in model-based control as an advantage with respect to other models, e.g. Finite Element Method -- The mathematical model of the HexFlex is achieved using metamodels -- The term methamodel is used to represent a simplified and efficient mathematical model of unknown phenomenon or computer codes – The metamodel of the HexFlex is performed from virtual analyses made using the Finite Element Method (FEM) -- Simulations of the metamodel were made founding good accuracy with respect to the virtual experiments
  • No hay miniatura disponible
    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/CAE
    This 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
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    Ítem
    Short Research Advanced Project: Development of Strategies for Automatic Facial Feature Extraction and Emotion Recognition
    (IEEE, 2017-10-18) Restrepo, David; Gomez, Alejandro; Restrepo, David; Gomez, Alejandro; Universidad EAFIT. Departamento de Ciencias; Modelado Matemático
    Emotions are a fundamental part of the personal and social skills of the human being. The behavior, intelligence, reason and decision making process are some of the topic that can be influenced by the emotional state of a person. In this paper we develop a computational way for emotion recognition though images using the Cohn-Kanade database to train a pattern recognition neural network and Viola Jones object detector to extract the information of the facial expression. The resulting neural network showed an overall accuracy of 90.7% in recognizing between 6 basic emotions such a surprise, fear, happiness, sadness, disgust and anger.
  • No hay miniatura disponible
    Ítem
    Symetrical Observability of Kinematic Parameters in Symmetrical Parallel Mechanisms
    (2012-07-13) Durango, Sebastián; Restrepo, David; Ruiz OE; Restrepo, John; Achiche, Sofiane; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
    This article presents an application of symmetry group theory in kinematic identification of parallel mechanisms of nlegs legs.