• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.9
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• pp.64-74
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• 2003

This paper proposes a new autonomous stationkeeping system suitable for geostationary satellite and conducts computer simulation to verify the proposed algorithm. The proposed onboard system receives pseudo-range signal from ground equipments located at two different position with long baseline, determines the orbit error in realtime and generates orbit control commands. For minimized onboard stationkeeping logic and better reliability, the orbit controller is designed to generate control signal to have the orbit roughly follow predetermined reference range data which is generated through ground based computer simulation. The reference range data is assumed to be uploaded with time tag. A simple orbit controller is proposed which combines the reference $\Delta$V and feedback control signal. Finally, the performance of the proposed system is verified through the computer simulations.

• Bulletin of the Korean Space Science Society
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• 2005.04a
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• pp.129-132
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• 2005

This paper describes BAUSAT-2 orbital thermal analysis and preliminary design of thermal control subsystem. To design thermal control subsystem of HAUSAT-2, we have considered active & passive thermal control method based on basic theory and themal equilibrium equation. Using this result, suitable thermal control method and material have been selected. We have designed thermal control subsystem based on analysis of HAUSAT-2's thermal environments on sun synchronous orbit with altitude 650km, inclination $98^{\circ}$ and thermal distribution and range expectation of each HAUSAT-2's surface. Thermal analysis consists of system level, box level and board level analysis. We have completed system level and box level analysis. Till now, board level analysis of main heat dissipation board in progress. Thermal control subsystem has designed according to thermal analysis result. This design is to maintain all of the HAUSAT-2 components within the allowable temperature limits. In future, STM

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.2
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• pp.165-171
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• 2016

The attitude control, station keeping and wheel off-loading at GEO-KOMPSAT-2 are realized by thrusters firings. Thrusters 1, 2 and 3 are mounted on the same axis as the solar array, which generates the plume disturbance largely. Therefore the effect of plume disturbance should be analyzed from satellite design phase. In this paper, we described the calculation method of plume disturbance and analyzed the plume disturbance of thruster 1,2 and 3 using GEO-KOMPSAT-2 initial configuration.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.8
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• pp.747-752
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• 2007

Domestic satellite development programme is generally classified into two categories: COMS as GEO satellite and KOMPSAT as LEO one. Each satellite has the on-board propulsion system fulfilling its own mission requirements. The COMS propulsion system provides the thrust and torque required for the insertion into GEO, attitude and orbit control/adjustment of spacecraft. It is the well-known Chemical Propulsion System(CPS) using bipropellants. On the other hand, the monopropellant propulsion system is employed in KOMPSAT, and its main role is on-station attitude control excluding the orbit transfer function. In this study, these two representative propulsion systems are compared and analysed as well, in terms of essential differences and important characteristics.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1998.10a
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• pp.9-9
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• 1998

다목적 실용위성의 궤도전이 및 위성체 자세제어를 위한 추진시스템의 설계요소에는 구조적 안전성, 우주환경에서의 열제어를 위한 회로 및 구성하드웨어 설계, 연료계통 맥압강하를 위한 장치설계 및 추력기 배기가스 영향을 고려한 형상설계 등이 있으며, 설계검증을 위해 부분해석이 수행된다. 또한 발사환경과 우주 궤도환경에서의 추진시스템 성능평가를 위한 연제어계 기능시험, 압력인증시험, 청정도시험 및 내부/외부 누설시험이 수행된다. 본 논문에서는 추진시스템 설계 및 조립공정에 대해 기술하였고, 시험분석을 통해 시스템의 설계 및 조립공정상의 신뢰성을 검증 분석하였다.

• Proceedings of the Korean Magnestics Society Conference
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• 2002.12a
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• pp.134-135
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• 2002

모든 인공 위성이 궤도 올라가서 정확한 업무를 수행하기 위해서는 정확한 위치 정보와 안정된 자세제어 시스템을 필요로 한다. 궤도에 올라간 후 안정된 자세를 잡기 위해서는 위성체의 덤블링 방지해야되므로 초기 자세제어가 매우 중요하다. 그리고, 안정된 제도에 도달하여 자세를 잡기 의해서는 정확한 자세 정보와 자세를 조절하는 장치가 필요하며, 이를 얻기 위해서 thruster, momentum wheel, 마그네틱 토커, 마그네토미터 등과 같은 장치들이 사용되어진다. (중략)

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1321-1322
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• 2003

무선통신기반의 이동폐색방식 열차제어시스템에서는, 열차위치를 폐색구간 단위로 검지하지 않고 실제 위치를 점단위로 검지하는 방식을 취하기 때문에, 종래와 같이 궤도회로에 의한 폐색구간 단위로 열차위치를 표시할 수 없게 된다. 이와 같이 궤도회로를 사용하지 않는 이동-폐색방식 열차제어시스템에서 현시 전개도를 통하여 열차운행상황을 나타내는 방안을 제시하였다.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.8
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• pp.842-848
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• 2005

The decoupling control using state feedback was once intensively studied during 1960's by many researchers. However, this control scheme was sensitive to the disturbance and Parameter variations. SMC(sliding mode control) is known as a robust control methodology to overcome such a disturbance. In this paper. the decoupling control by means of SM(sliding mode) for a trajectory control of a two-degrees-of- freedom manipulator was discussed. The position and velocity of manipulator tip were adopted to compose a nonlinear error functions. The reference inputs of the controller can be decided by switching function combined with the desired position and velocity. Simulation result is provided to verify the effectiveness of the proposed control scheme.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.1
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• pp.103-109
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• 2006

In this paper, VDS(Vehicle Dynamics Simulator) and ACS(Attitude Control Simulator) are developed and are verified using PILS(Process In-the Loop Simulation) between VDS and ACS. VDS is including the AOCS(Attitude & Orbit Control Subsystem) hardware modeling of geosynchronous satellite and consists of modulation concept. ACS performs the attitude determination using sensor data and generates the attitude control commands. In order to transfer the data between VDS and PCDU(Power Control & Distribution Unit), data acquisition boards were mounted. VDS performance is verified using HILS(Hardware In-the Loop Simulation) between VDS and PCDU.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.727-730
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• 2011

본 논문에서는 3차원 자기부상열차에 대한 열차-가이드웨이 상호작용 해석기법을 제시하고자 한다. 수직 및 수평방향 변위, 피칭, 롤링 그리고 요잉에 대한 자유도를 각 보기와 차체에 대해 고려하여 총 25자 유도 자기부상열차에 대한 운동방정식을 유도하였다. 제어방식으로는 UTM01에 적용된 제어기법을 이용하였고, 궤도 틀림을 고려하기 위하여 미국 FRA에 적용하고 있는 궤도 불규칙성에 대한 밀도 스펙트럼 함수를 이용하여 조도를 생성하였다. 같은 조건하에 2차원 모델과 3차원 모델의 동적응답 결과를 비교하여 타당성을 확인하였고, 2차원 모델에서 고려할 수 없는 수평방향 조도를 도입하였을 때 수직방향 부상공극에는 두드러진 영향을 미치지 않았으나, 수평방향 부상변위에 있어서 중요하게 작용함을 확인하였다.