• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.965-968
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• 2004

This paper describes the development of the test path for Eclipse-II, a parallel mechanism motion simulator. Eclipse-II which can be used as a base for general motion simulators, enables unlimited continuous 360-degree spinning in any rotational axes plus finite X, Y, and Z translation motions. The advantage of enabling continuous 360-degree spinning allows various motions for virtual reality. In this paper, the development of the test path to verify the robustness of the Eclipse-II motion simulator is described. The test motions, which satisfy the requirements of test path, are suggested and washout filter enables these motions reproduced in the limited workspace. The trial run is conducted to verify the robustness of the Eclipse-II motion simulator. Additionally the standard data format of virtual reality for Eclipse-II One Man Ride is suggested.

• 한국정밀공학회지
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• 제18권7호
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• pp.19-26
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• 2001

• 한국정밀공학회지
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• 제29권4호
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• pp.441-448
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• 2012

This paper describes the optimal home positioning algorithm of Eclipse-II, a new conceptual parallel mechanism for motion simulator. Eclipse-II is capable of translation and 360 degrees continuous rotation in all directions. In unexpected situations such as emergency stop, riders have to be resituated as soon as possible through a shortest translational and rotational path because the return paths are not unique in view of inverse kinematic solution. Eclipse-II is man riding. Therefore, the home positioning is directly related to the safety of riders. To ensure a least elapsed time, ZYX Euler angle inverse kinematics is applied to find an optimal home orientation. In addition, the subsequent decrease of maximum acceleration and jerk values is achieved by combining the optimal return path function with cubic spline, which consequently reduces delivery force and vibration to riders.

• Journal of Astronomy and Space Sciences
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• 제9권2호
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• pp.154-164
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• 1992

The Mg II lines been extracted from the IUE archival spectra of 32 Cygni to investigate the effect of the atmospheric eclipse. The UV light curve has been reduced from the continuum flux at the center wavelength of 2807.5 ${\AA}$ in the IUE spectra. The equivalent width of the Mg II k absoption line has been measured for each spectra. The results of the light variation and flux tracing of the absorption line at the vicinity of the primary eclipse confirmed the atmospheric eclipse. The atmospheric effect lasted until the phase 0.06 in the absorptin line tracing, while it lasted until the phase 0.02 in the UV light curve, respectively.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 추계학술대회 논문집
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• pp.117-118
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• 2007

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.286-291
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• 2002

We present the analysis and design of a new six degree-of-freedom parallel mechanism, Eclipse-II, which can be used as a basis for general motion simulators. This mechanism allows x, y and z-axis translations and a, b and c-axis rotations. Most significantly, it presents the advantage of enabling continuous 360 degrees spinning of the platform. We first describe the computational procedures for the forward and in inverse kinematics of the Eclipse-II. Next, the complete singularity analysis is presented for the two cases of end-effector and actuator singularities. Two additional actuators are added to the original mechanism to eliminate both types of singularities with in the workspace. Some practical aspects of the prototype development are introduced.

• Journal of Astronomy and Space Sciences
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• 제8권2호
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• pp.125-131
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• 1991

UBV observations at Yonsei University Observatory (500 and 537 observations each at Ilsan Station and at Campus Station) were made for the latest eclipse of $\zeta$ Aur in 1987-1988. Orbital period of Saijo and Saito has been confirmed and the light and color variations on the night JD 244730 are found.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 추계학술대회 논문집
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• pp.115-116
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• 2007

• 한국항공우주학회지
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• 제41권12호
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• pp.950-958
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• 2013

달 궤도선은 한국형발사체(KSLV-II)에 실려 지구 저궤도에 투입된 후, 지상 안테나를 이용한 달 궤도선의 추적데이터 획득 및 궤도결정 과정을 거쳐 적절한 시점에서 TLI(Trans Lunar Injection) 엔진을 점화시켜야 한다. 본 논문은 달 궤도선을 나로우주센터에서 발사하여 달 궤도에 진입하기까지 여러 단계로 나누고 발사 방위각 및 발사창 분석부터 TLI 및 LOI(Lunar Orbit Insertion) 분사 위치에 따른 속도증분(${\Delta}V$) 그리고 가시성 및 식 기간 분석까지 수행하여 직접 전이궤적의 전반적인 특성을 분석하였다. 본 논문은 향후 달 임무 설계 시 관성비행 기간 및 전이기간에 따라 속도증분이 어떻게 변하는지에 대한 전반적인 내용을 파악하는데 도움이 되고, 발사 시각 선정과 연료소모를 줄일 수 있는 파라미터 선정에 도움을 줄 것으로 판단된다.

• Journal of Astronomy and Space Sciences
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• 제8권1호
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• pp.99-113
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• 1991

수치적인 방법을 이용하여 인공위성의 궤도를 예보할 수 있는 소프트웨어 시스템 (IODS: ISSA Orbit Determination System)을 개발하였다. IODS의 궤도예보 정확도틀 평가하기 위히여 기상위성 NOAA-ll호와 정지위생 INTELSAT-V의 궤도를 예보하였고, 그 결과를 중앙기상대와 금산 위생통신지구국의 위성추적 자료와 비교하였다. 그리고 인공위성애 미치는 여러가지 섭동력을 정량적으로 분석하였다 한편, 동경 100도에 상공에 위치한 정지위성(KORSAT-l)의 궤도을 가정하여 궤도가 시간에 따라 변하는 양상을 IODS툴 이용하여 분석하였으며, KORSAT-l이 지구의 그림자에 들어가는 식현상을 예측하고 분석하였다.