• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.83.2-83
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• 2001

This paper presents a new formulation approach to reduce computational burden of the direct kinematics of 6-dof haptic devices with three sets of a parallel-serial linkage. Their direct kinematics has been formulated through employing the Denavit-Hartenberg notation, which results in complicated formulation procedures and heavy computational burden. For reducing these problems, this paper reconfigures the haptic devices into an equivalent kinematic model of the 3-6 Stewart-Gough Platform that has three connecting joints on the moving platform. Moreover, the direct kinematics of the 3-6 Platform can be effectively formulated by using the proposed Tetrahedron Approach.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.2 no.1
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• pp.13-17
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• 2001

The configuration design of kinematic mechanisms of industrial sewing machine has been studied using a functional approach. The configuration design methodology has been applied to shorten the development cycle time of mechanisms and to manage design data efficiently Expert system has been used to embody the decomposition of functional requirements. It has been interfaced with a CAD system through the API program to show the assembly and parts of the mechanism. Constraints also can be handled by the expert system through the rule induction and the case based reasoning process. The configuration design system includes the kinematical analysis and optimization of the mechanisms of an industrial sewing machine by the interface between the expert system and an analysis program by means of API Program supplied by expert system. The conceptual design of sewing machine mechanism can be Performed rapidly and efficiently.

• Journal of Sensor Science and Technology
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• v.28 no.2
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• pp.81-87
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• 2019

One of the major issues in inertial and magnetic measurement unit (IMMU)-based 3D orientation estimation is compensation for magnetic disturbances in magnetometer signals, as the magnetic disturbance is a major cause of inaccurate yaw estimation. In the proposed approach, a kinematic constraint is used to provide a measurement equation in addition to the accelerometer and magnetometer signals to mitigate the disturbance effect on the orientation estimation. Although a Kalman filter (KF) is the most popular framework for IMMU-based orientation estimation, a complementary filter (CF) has its own advantages over KF in terms of mathematical simplicity and ease of implementation. Accordingly, this paper introduces a quaternion-based CF with a constraint-combined correction equation. Furthermore, the weight of the constraint relative to the magnetometer signal is adjusted to adapt to magnetic environments to optimally deal with the magnetic disturbance. In the results of our validation experiments, the average and maximum of yaw errors were $1.17^{\circ}$ and $1.65^{\circ}$ from the proposed CF, respectively, and $8.88^{\circ}$ and $14.73^{\circ}$ from the conventional CF, respectively, showing the superiority of the proposed approach.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.22 no.3
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• pp.217-223
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• 2004

In order to improve real-time positioning accuracy, a number of methods have been tested and one of those is the inverted RTK(Real-time kinematic) that gives a precise positioning by handling carrier phase measurements. For the inverted RTK positioning, it needs the L1 phase measurement at least for 1～2 minutes and the additional reference stations/communication system and a data processing server are required. The L1 code and carrier phase measurements for real-time application are used simultaneously and then Kalman filter is applied to estimate integer ambiguities. Double differenced integer ambiguities are resolved by utilizing the FARA(Fast Ambiguity Resolution Approach). In this paper, we propose the method to improve the positioning accuracy and performed the field tests for several baselines from DAEJ reference station in KAO(Korea Astronomy Observatory).

• Korean Journal of Applied Biomechanics
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• v.13 no.2
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• pp.29-47
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• 2003

This study is to analyze the kinematic variables in release motion of discuss throwing. For the matter, 5 people from the national team and collegiate discuss throwing in the year 2001 were chosen as the subjects and two S-VHS video cameras set in 60frames/sec were used for recording their motions. Coordinated raw positions data through digitizing are smoothing by butter-worth 's low-pass filtering method at a cut off frequency 6.0Hz. and the direct linear transformation(DLT) method was employed to obtain 3-D position coordinates. The conclusions were as follows; 1. The better record players showed the shorter approach time in the last support phase. 2. In the displacement CG, the better record players showed the shorter displacement in medial-lateral direction, and the longer displacement in horizontal direction. In the motion, the COG showed longer displacement vertical direction. 3. The better record players showed the faster horizontal velocity than vertical velocity in the release. 4. The better record players showed to take the posture of vertical axis in the release.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.4
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• pp.92-98
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• 2006

In this paper, a planar car model with 3 degrees of freedom was analyzed using the concept of the roll center. To avoid ambiguity, force components which require experimental data were excluded. Only kinematic approach was used to find the position and orientation of the vehicle body and the position of the roll center. The roll center was found by the pole with infinitesimal movement and Kennedy-Aronhold theorem. Centrodes, which are the loci of instantaneous centers of planar motion, were constructed with analyzed results to show characteristics of vehicle body motion. To verify the presented analysis method in this paper, the locus of the roll center and the motion of a 3 D.O.F. planar car model were compared with those of the 1 D.O.F. model.

• Journal of information and communication convergence engineering
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• v.8 no.2
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• pp.145-149
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• 2010

In this paper, we propose a kinematic approach to estimating the real-time moving object. A new scheme for a mobile robot to track and capture a moving object using images of a camera is proposed. The moving object is assumed to be a point-object and projected onto an image plane to form a geometrical constraint equation that provides position data of the object based on the kinematics of the active camera. Uncertainties in the position estimation caused by the point-object assumption are compensated using the Kalman filter. To generate the shortest time path to capture the moving object, the linear and angular velocities are estimated and utilized. The experimental results of tracking and capturing of the target object with the mobile robot are presented.

• Transactions of Materials Processing
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• v.15 no.8 s.89
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• pp.533-538
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• 2006

A simplified numerical procedure to predict drawbead restraining forces(DBRF) has been developed based on the hybrid membrane/bending method which superposes bending effects onto membrane solutions. As a semi-analytical method, the new approach is especially useful to analyze the effects of various constitutive parameters. The present model can accommodate general anisotropic yield functions along with non-linear isotropic-kinematic hardening under the plane strain condition. For the preliminary results, several sensitivity analyses for the process and material effects such as friction, drawbead depth, hardening behavior including the Bauschinger effect and yield surface shapes on the DBRF are carried out.

• Transactions of Materials Processing
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• v.26 no.1
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• pp.41-47
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• 2017

Cyclic behavior of advanced high strength steel sheets was measured using an inverse-optimization approach with pre-straining and bending. First, tensile specimens were pre-strained, and three-point bending was conducted for the pre-strained specimens. By using the inverse finite element optimization, the combined isotropic-kinematic hardening parameters that minimize the error between the measured and predicted bending force-displacement curves. The measured cyclic behavior agreed well with the cyclic behavior measured by sheet tension-compression test, which confirms the validity of the measuring procedure based on inverse optimization.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.507-512
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• 1997

This paper presents a method of finding optitnal joint torques of two robots when they hold an object simultaneously. Although the importance of the multiple cooperating robot system increases for more flcviblc ni;mufacturing automation, dynamic solutions to multi-robot system forming closcd kinematic chain is not easy to find. Newton-Eulcr approach is used for the dynamic formulation of two robots fonn~ng closcd kincmatic chains gmsping a rigid body object. The nrcthodology to optimize the joint torques to satisfy given criterta and obtain bettcr control of the system is discussed. The scheme is illustrated by an example.