• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2005년도 한국우주과학회보 제14권1호
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• pp.129-132
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• 2005

본 논문에서는 HAUSAT-2의 궤도 열 해석과 열 제어계의 예비설계를 살펴본다. HAUSAT-2의 열 제어계를 설계하기 위해서 우선 열 제어의 기본 이론 및 열 평형 방정식을 바탕으로 능동 및 수동의 각종 열 제어 방법을 고려하여 HAUSAT-2에 적합한 열 제어 방법 및 재질을 선정하였다(Karam 1998). 또한, 예상궤도인 고도 650km, 경사각 $98^{\circ}$의 태양동기궤도에서 HAUSAT-2가 처해지는 열 환경에 대한 분석 및 위성체의 각 면에 가해지는 은도 분포 및 범위를 예측하여 이를 바탕으로 열 제어계를 설계하였다. 열 해석은 기본적으로 시스템레벨의 해석, 부품레벨의 해석, 보드레벨의 해석 차순으로 진행되었으며, 현재 HAUSAT-2의 열 해석은 발열이 비교적 많은 보드의 해석까지 진행된 상태이며, 이러한 열 해석을 통해서 얻은 결과는 요구조건을 만족하지 못하는 부분에 대해 설계 변경 등을 통해서 모든 부품이 허용온도 범위를 유지하도록 HAUSAT-2의 열 제어계를 설계하였다. 향후 구조-열 모델(STM; Structure & Thermal Model)을 제작한 후 열 진공시험을 통해 열 해석 결과에 대한 검증을 수행할 것이다.

• 한국주조공학회지
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• 제25권5호
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• pp.209-215
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• 2005

The design of the Metal mold casting should consider several variables such as the material properties and shape of the mold. In particular, the thermal stress generated by the thermal expansion and contraction depending on the thermal gradient of the mold causes partial plastic deformation on the mold, which causes damage or fracture of the cast. Consequently, the thermal deformation along with thermal stress leads to thermal deformation of the cast itself. In this study, the temperature analysis of the cast and mold is simulated by FDM to control the thermal deformation and stress as a result of the thermal gradient of mold. Using the results from FDM simulation, the thermal deformation and stress are analyzed by FEM and, the optimal mold design with minimum thermal deformation of the cast is suggested.

• 한국전산유체공학회지
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• 제12권3호
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• pp.62-68
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• 2007

A conceptual thermal design is performed for the optical payload system of a geostationary satellite. The optical payload considered in this paper is GOCI(Geostationary Ocean Color Imager) of COMS of Korea. The radiative thermal control system is employed in order to expect a small thermal gradient in the telescope structure of GOCl. Two design margins are applied to the dedicated radiator dimensioning, and three kinds of configuration to the heater power sizing. A Monte-Carlo ray tracing method and a network analysis method are utilized to calculate radiative couplings and thermal responses respectively. At the level of conceptual design, sizing thresholds are presented for the radiator and heater on the purpose of determining the mass and power budget of the spacecraft.

• International Journal of Control, Automation, and Systems
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• 제6권2호
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• pp.160-170
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• 2008

Temperature control of an enclosed thermal system which has many applications including Rapid Thermal Processing (RTP) of semiconductor wafers showed an input-constraint violation for nonlinear controllers due to inherent strong coupling between the elements [1]. In this paper, a constrained nonlinear optimal control design is developed, which accommodates input constraints using the linear algebraic equivalence of the nonlinear controllers, for the temperature control of an enclosed thermal process. First, it will be shown that design of nonlinear controllers is equivalent to solving a set of linear algebraic equations-the linear algebraic equivalence of nonlinear controllers (LAENC). Then an input-constrained nonlinear optimal controller is designed based on that LAENC using the constrained linear least squares method. Through numerical simulations, it is demonstrated that the proposed controller achieves the equivalent performances to the classical nonlinear controllers with less total energy consumption. Moreover, it generates the practical control solution, in other words, control solutions do not violate the input-constraints.

• Journal of Astronomy and Space Sciences
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• 제29권1호
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• pp.23-31
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• 2012

Thermal analysis and control design are prerequisite essential to design the satellite. In the space environment, it makes satellite survive from extreme hot and cold conditions. In recent years CubeSat mission is developed for many kinds of purpose. Triplet Ionospheric Observatory (TRIO)-CubeSat for Ion, Neutral, Electron, MAgnetic fields (CINEMA) is required to weigh less than 3 kg and operate on minimal 3 W power. In this paper we describe the thermal analysis and control design for TRIO-CINEMA mission. For this thermal analysis, we made a thermal model of the CubeSat with finite element method and NX6.0 TMG software is used to simulate this analysis model. Based on this result, passive thermal control method has been applied to thermal design of CINEMA. In order to get the better conduction between solar panel and chassis, we choose aluminum 6061-T6 for the material property of standoff. We can increase the average temperature of top and bottom solar panels from $-70^{\circ}C$ to $-40^{\circ}C $ and decrease the average temperature of the magnetometer from $+93^{\circ}C$ to $-4^{\circ}C$ using black paint on the surface of the chassis, inside of top & bottom solar panels, and magnetometer.

• 한국의류학회지
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• 제39권1호
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• pp.55-62
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• 2015

This study investigated the thermal insulation of an air-cell pack embedded jacket and down jackets to understand the potential of air-cell pack as a filler for winter outdoor wear. A thermal manikin measured the thermal insulation of the following jackets: HD (heavy down jacket, total weight (Tw) 750g, goose down weight (Dw) 350g), LD (light down jacket, Tw 560g, Dw 140g), AF (air-cell pack embedded jacket, Tw 490g, trunk goose down in LD was replaced to air cell), F (film jacket, Tw 469g, but removed the air in the air-cell pack from the AF), and Control (control jacket, Tw 438g, removed the air-cell pack film from the F). Thermal insulations of each experimental condition were measured in a static standing posture. Total thermal insulations (IT) were 1.29clo (HD), 1.23clo (LD), 1.16clo (AF), 1.20clo (F), and 1.08clo (Control). Body regional thermal insulation was higher in the chest and back than in the abdomen and hip in all conditions. The results suggest that an economical and versatile outdoor jacket with superior thermal insulation will be feasible if the air volume is properly controlled in air-cell pack embedded jackets in consideration of regional different distribution and used in combination with film and down.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.199-202
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• 2007

COMS (Communication, Ocean and Meteorological Satellite) is a geostationary satellite and has been developing by KARI for communication, ocean observation and meteorological observation. Conventional thermal control design, using MLI (Multi Layer Insulation), OSR (Optical Solar Reflector), heater and heat pipe, is utilized. Ka-band components are installed on South wall, while other equipment for sensors are installed on the opposite side, North wall. High dissipating communication units are located on external (surface) heat pipe and are covered by internal insulation blankets to decouple them from the rest of the satellite. External satellite walls are covered by MLI or OSR for insulation from space and for rejection internal heat to space. The ocean and meteorological sensors are installed on optical benches on the top floor to decouple thermally from the satellite. Single solar array wing is adopted in order to secure clear field of view of radiant cooler of IR meteorological sensor. This paper presents principles of thermal control design for the COMS.

• 전기학회논문지P
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• 제53권2호
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• pp.94-99
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• 2004

In this paper, We design a RF control system capable of handling multiple POS thermal printers. The system has three parts including embedded master controller, RF controller and high-speed thermal printer. Specially the designed linux embedded controller has simple structure and high performance to connect the TCP/IP network. The effectiveness of the developed RF control system is shown by proposed food ordering system.

• 한국항공우주학회지
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• 제38권12호
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• pp.1232-1239
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• 2010

(주)쎄트렉아이는 지구관측위성의 주 탑재체로 사용될 고해상도 전자광학카메라, EOS-C Ver.3.0을 개발 중이다. EOS-C Ver.3.0은 현재 운용중인 DubaiSat-1의 주 탑재체인 EOS-C Ver.2.0 개발 경험을 바탕으로 능동 열제어 방식과 수동 열제어 방식을 적절하게 혼용하여 보다 향상된 성능을 갖도록 설계되었다. 설계를 바탕으로 STM을 개발하여 인증(qualification) 수준의 열진공 시험을 수행하여 설계 여유(design margin)를 확인하였다. 또한 열평형 시험 결과를 이용하여 열제어계 설계에 사용한 열-수치 모델에 대한 검증 작업을 수행하였으며, 열-수치 모델이 실제 열적 특성을 잘 모사하고 있음을 확인하였다.

• 항공우주시스템공학회지
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• 제18권2호
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• pp.71-78
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• 2024

초기 열설계 과정의 경우 복잡한 궤도 열 환경 조건에서 다양한 설계 변수에 따른 열적 영향성 판단을 해야 하므로, 열 설계/분석에 많은 시간이 소요된다. 따라서, 초기 설계 단계에서 시간을 효율적으로 단축시키기 위해서는 최적의 설계 변수 도출과 이에 따른 온도 예측이 신속히 이루어져야 한다. 상기 문제점에 기인하여 차수축소모델을 활용한 최적 설계 전문 소프트웨어인 Veritrek이 2018년에 출시되었다. 본 논문에서는 Veritrek 소프트웨어를 활용하여 그라파이트시트 기반 냉각기 열 제어 시스템에 대해 차수축소모델 구축과 민감도 분석, 최적 설계 분석을 수행하여 냉각기의 허용온도를 만족할 수 있는 그라파이트시트의 적층 수, 방열판 면적 및 두께에 대한 최적설계 수치를 도출하였다.