• 생물환경조절학회지
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• 제13권1호
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• pp.1-7
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• 2004

본 연구는 오이수확기의 매니퓰레이터 개발을 위한 기구학적 분석을 하는 것이다. 매니퓰레이터의 정방향 기구학 및 역방향 기구학 분석을 한 후 실제 장치의 반복오차 측정실험을 통해 이론 값을 검증하였다. 매니퓰레이터는 총 세 개의 링크로서 한 개의 수직링크와 두 개의 호전링크로 구성되어져 있으며, 세 개의 스테핑 모터가 각 관절에 장착되어 링크에 동력을 전달한다. 주요 연구결과를 요약하면 다음과 같다. D-H Parameter를 이용하여 정방향 기구학에 의한 매리퓰레이터의 변환 연산자를 얻었다. 역방향 기구학의 해는 두가지로 나타났으며 삼각함수를 이용하여 해를 구하였다. 매리퓰레이터의 반복오차를 측정한 검증 실험에서는 X, Y, Z축에 대하여 반복 오차가 최대 2.60mm, 2.05mm, 1.55mm로 나타났으며, 정방향 및 역방향 기구학에서 오차의 최대지점 및 최소지점의 실제 좌표는 일치하였다. 반복오차 측정 결과는 매리퓰레이터의 목표지점인 오이의 직경에 비해 비교적 작게 나타났다. 측정오차는 실험중 발생한 실험오차로 판단된다. 매니퓰레이터의 오차를 줄이고 작업능률의 향상을 위해서는 링크의 수를 줄이고 오이의 품종 및 재배환경을 고려하여야 하며, 경량이면서도 견고한 재료를 사용하여 하중을 줄여야 한다.

• 대한기계학회논문집A
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• 제25권9호
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• pp.1384-1390
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• 2001

This paper deals with the forward kinematics of the 6-6 Stewart platform of planar base and moving platform using one extra linear sensor. Based on algebraic elimination method, it first derives an 8th-degree univariate equation and then finds tentative solution sets out of which the actual solution is to be selected. In order to provide more exact solution despite the error between measured sensor value and the theoretic alone, a correction method is also used in this paper. The overall procedure requires so little computation time that it can be efficiently used for real-time applications. In addition, unlike the iterative scheme e.g. Newton-Raphson, the algorithm does not require initial estimates of solution and is free of the problems that it does not converge to actual solution within limited time. The presented method has been implemented in C language and a numerical example is given to confirm the effectiveness and accuracy of the developed algorithm.

• 한국운동역학회지
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• 제24권4호
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• pp.317-327
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• 2014

As a single subject study, it was purposed to investigate kinematic differences between Yang Hak Seon vault (i.e., handspring forward and salto forward straight with triple twist, Yang-1 vault hereafter) and Tsukahara $1260^{\circ}$ twist with salto forward straight (Yang-2 vault hereafter) in gymnastics. Yang Hak-Seon (23 years, 160 cm, and 52 kg) voluntarily participated in this study. Motion capture system, consisting of fourteen cameras, were used to measure Yang-2 vault with the sampling rate of 200 Hz. Twenty six reflective markers were placed on major anatomical points of 15 body segments. Successful two trials of Yang-2 vault were collected and analyzed for the comparison. Compared Yang-1 results were based on the previous study of Park and Song (2012). Results indicated superior linear kinematics of Yang-1 vault to those of Yang-2 vault before the touchdown of vault table. However, Yang-2 vault revealed superior angular kinematics to Yang 1 vault showing more trunk twist angle (a triple and a half twist) and its faster angular velocity during the airborne. The Yang 2 vault could has advantage of increasing angular motion than Yang 1 vault as a result of a half turn off the springboard onto the vault table and a sequential touchdown of the hands.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.137-138
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• 2010

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 추계학술대회 논문집
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• pp.179-180
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• 2006

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.803-804
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• 2011

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.237-240
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• 1997

The casing oscillator is a construction equipment to clamp, oscillate and push a casing for foundation work. In case that the casing oscillator is operated on the slant ground, if another construction heavy equipment is not used, it is impossible to insert the casing in ground using only casing oscillator. So in this paper, we present the new casing oscillator that need not to level the ground for work of casing insertion. This mechanism can execute 4 DOF motion by actuating 5 single - rod hydraulic cylinders. The forward kinematics analysis of the casrng oscillator by tetrahedron geometry is performed so predict workspace, direction and poison of casing oscillatoer.

• 한국컴퓨터정보학회논문지
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• 제10권5호
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• pp.171-177
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• 2005

본 논문에서는 Forward Kinematics의 개념을 이용하여 각도변화에 따른 좌표계산 방법을 설명하고, Workspace 생성을 위한 반복적 방정식 (Recursive Equation)을 동차좌표계를 이용하여 수식으로 표현한다. 그리고 이 반복적 방정식(Recursive Equation)과 인체모델 관절의 한계 각도를 접목시켜 인체모델의 Workspace생성을 위한 알고리즘을 제시하고, 제시한 알고리즘을 이용하여 인체모델의 Workspace 생성결과를 그래픽으로 표현하였으며 알고리즘의 적절성을 보였다.

• The Journal of Korean Physical Therapy
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• 제26권3호
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• pp.140-146
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• 2014

Purpose: Differences in scapular kinematics and muscle activity appear in the forward head and rounded shoulder posture (FHRSP). Thus, the aim of this study was to investigate the following effects according to different postures on scapular kinematics and muscle activity around scapular region in individuals with and without FHRSP during overhead reaching task. Methods: Thirty pain-free subjects with/without FHRSP participated in this study. All subjects were positioned into three positions: habitual head posture (HHP), self-perceived ideal head posture (SIHP) and therapist-perceived neutral head posture (TNHP). Muscle activities of upper trapezius (UT), lower trapezius (LT) and serratus anterior (SA) were measured during overhead reaching task. Results: Muscle activity of trapezius muscle (UT and LT) during HHP was significantly higher than SIHP and TNHP in FHRSP group (p<0.05), but there was no difference between SIHP and TNHP. SA also significantly increased muscle activity in HHP more than SIHP and TNHP in FHRSP group (p<0.05), but there was no significant difference between SIHP and TNHP. In Non-FHRSP group, although there was a tendency of different muscle activities among three postures, it was not statistically significant. Conclusion: This result demonstrates that muscle activity associated with overhead reaching task is increased in HHP which affects the scapular kinematics and SIHP contributes changed scapular kinematics and proper recruitment of muscle activity in FHRSP similarly to TNHP.

• 한국정밀공학회지
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• 제16권8호
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• pp.186-192
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• 1999

This paper introduces a study of a method for the forward kinematic analysis, which finds the 6 DOF motions and velocities from the given six cylinder lengths in the Stewart platform. From the viewpoints of kinematics, the solution for the inverse kinematic is easily found by using the vectors of the links which are composed of the joint coordinates in base and plate frames, to act contrary to the serial manipulator, but forward kinematic is difficult because of the nonlinearity and complexity of the Stewart platform dynamic equation with the multi-solutions. Hence we, first in this study, introduce the linear estimator using the Luenberger's observer, and the estimator using the nonlinear measured model for the forward kinematic solutions. But it is difficult to find the parameter of the design for the estimation gain or to select the estimation gain and the constant steady state error exists. So this study suggests the estimator with the estimation gain to be learned by the neural network with the structure of multi-perceptron and the learning method using back propagation and shows the estimation performance using the simulation.