• 한국태양에너지학회 논문집
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• 제32권spc3호
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• pp.269-274
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• 2012

The research of the biological mimics robot which utilizes the operation of the organism is progressed on the ground, aerial, and underwater robot sector. In the field of flying robot, the research for implementing the wing movement structure of the bird and insect is progressed. The joint structure for the wing movement of the bird is implemented. The operation of the wing is simulated. For this purpose, by using the Matlab/Simulink, the joint structure of the wing is modelled. The joint movement of the wing is tested through the simulation.

• 한국공간구조학회논문집
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• 제16권1호
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• pp.65-72
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• 2016

Aerodynamic performance of solar wing system has been evaluated through wind tunnel test. The test model has 12 panels, each supported by 2 cables. The panels were installed horizontally flat, and gaps between panels were set constant. Sag ratios of 2% and 5%, and wind directions between $0^{\circ}$ and $90^{\circ}$ were considered. Mass of test model was determined considering the mass of full scale model, and Froude number and Elastic parameter were satisfied by adjusting the mean wind speed. From the wind tunnel test, it was found that the aerodynamic performance of the solar wing system is very dependent on the wind directions and sag ratios. When the sag was 2%, the fluctuating displacements between the wind directions of $0^{\circ}$ and $30^{\circ}$ increase proportionally to the square of the mean wind speed, implying buffeting-like vibration and a sudden increase in fluctuating displacement was found at large mean wind speed for the wind directions larger than $40^{\circ}$. When the wind direction was larger than $60^{\circ}$, a sudden increase was found both at low and large mean wind speed. When the sag ratio is 5%, distribution of mean displacements is different from that of sag ratio of 2%, and the fluctuating displacements show very different trend from that of sag ratio of 2%.

• 항공우주시스템공학회지
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• 제10권1호
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• pp.43-50
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• 2016

In order to suggest the optimal manufacturing technology of composite wings of solar-powered unmanned aerial vehicles, this study compared forming technologies to reduce wing weight for long-endurance flight and to improve the manufacturing process for cost-saving and mass production. It compared the manufacturing time and weight of various composite wing molding technologies, including cocuring, secondary bonding, and manufacturing by balsa. As a result, wing weight was reduced through cocuring methods such as band type composite fiber/tape lamination technology, which enabled prolonged flight duration. In addition, the reduced manufacturing time led to a lower cost, which is a good example of weight lightening for not only small solar-powered UAVs, but also composite aircraft.

• International Journal of Aeronautical and Space Sciences
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• 제17권1호
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• pp.132-138
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• 2016

Korea Aerospace Research Institute (KARI) is developing an electric-driven HALE UAV in order to secure system and operational technologies since 2010. Based on the flight tests and design experiences of the previously developed electric-driven UAVs, KARI has designed EAV-3, a solar-powered HALE UAV. EAV-3 weighs 53kg, the structure weight is 22kg, and features a flexible wing of 19.5m in span with the aspect ratio of 17.4. Designing the main wing and empennage of the EAV-3 the amount of the bending due to the flexible wing, 404mm at 1-G flight condition based on T-800 composite material, and side wind effects due to low cruise speed, $V_{cr}=6m/sec$, are carefully considered. Also, unlike the general aircraft there is no center of gravity shift during the flight because of the EAV-3 is the solar-electric driven UAV. Thus, static margin cuts down to 28.4% and center of gravity moves back to 31% of the Mean Aerodynamic Chord (MAC) comparing with the previously designed the EAV-2 and EAV-2H/2H+ to upgrade the flight performance of the EAV-3.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
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• pp.404-405
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• 2012

The research of the biological mimics robot which utilizes the operation of the organism and which it applies to the robot is progressed on the ground, aerial, and underwater robot sector. In the field of flying robot, the research for implementing the wing movement structure of the bird and insect is progressed. The joint structure for the wing movement of the bird is implemented. The operation of the wing is simulated. For this purpose, by using the Matlab/Simulink, the joint structure of the wing is modelled. The joint movement of the wing is tested through the simulation.

• 항공우주시스템공학회지
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• 제10권4호
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• pp.50-58
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• 2016

선행 연구 개발을 통하여 장기 체공 태양광 무인기 복합재 날개의 경량화는 매우 중요한 요소임을 확인하였다. 날개 외피의 좌굴 방지와 비틀림 방지 역할을 하는 구조물인 리브는 날개의 구성 요소 중에 필수적이다. 본 연구는 최적의 복합재 리브를 설계, 제작하기 위하여 복합소재의 이방성 특성을 고려한 다양한 적층 패턴 적용 및 형상에 대하여 리브를 제작하였고. MSC. Patran/Nastran을 이용한 유한요소 해석을 통하여 최대 하중 및 변위 형상을 확인하였으며, 구조 시험을 통하여 측정된 시험 결과를 바탕으로 최적의 리브를 제시하였다.

• 항공우주시스템공학회지
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• 제10권1호
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• pp.59-65
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• 2016

Korea Aerospace Research Institute (KARI) is developing an electric-driven HALE UAV in order to secure system and operational technologies since 2010. Based on the 5 years of flight tests and design experiences of the previously developed electric-driven UAVs, KARI has designed EAV-3, a solar-powered HALE UAV. EAV-3 weighs 53 kg, the structure weight is 21 kg, and features a flexible wing of 19.5 m in span with the aspect ratio of 17.4. Designing the main wing and empennage of the EAV-3 the amount of the bending due to the flexible wing, 404 mm at 1-G flight condition based on T-800 composite material, and side wind effects due to low cruise speed, V_cr = 6 m/sec, are carefully considered. Also, unlike the general aircraft there is no center of gravity shift during the flight. Thus, the static margin cuts down to 28.4% and center of gravity moves back to 31% of the Mean Aerodynamic Chord (MAC) comparing to the previously developed scale-down HALE UAVs, EAV-2 and EAV-2H, to minimize a trim drag and enhance a performance of the EAV-3. The first flight of the EAV-3 has successfully conducted on the July 29, 2015 and the test flight above the altitude 14 km has efficiently achieved on the August 5, 2015 at the Goheung aviation center.

• 한국항공우주학회지
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• 제42권1호
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• pp.47-58
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• 2014

본 연구에서는 대체에너지로 태양광과 수소재생연료전지를 사용하는 고고도 장기체공 무인기의 초기 사이징을 수행하였다. 박스 윙 형태의 형상 대신 해외에서 연구가 많이 진행되어 상대적으로 기본 자료들이 풍부한 글라이더 형태의 형상을 선택하였다. 이륙중량 150 kg 급으로 추진 시스템은 모터와 프로펠러, 태양광 전지, 전기분해를 통해 재충전이 가능한 액체수소 연료전지로 구성되어있다. 하루 동안 순항 비행 시 필요한 최소 요구 에너지와 낮 시간으로부터 얻을 수 있는 태양광 에너지와의 에너지 균형을 고려하여 가로세로비, 날개 길이, 면적 등 항공기 설계변수를 변화시키면서 전체 이륙중량을 추정하였다.

• 한국항공운항학회지
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• 제19권2호
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• pp.1-9
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• 2011

Several studies on the development for solar powered uninhabited aerial vehicles(UAVs) are under way as the use of the renewable energy becomes more and more important these days. This paper is for the conceptual design by a discrete and iterative method. An initial design point with 1.5 meter wing span is determined in the global design, which deploys the mass and energy balances among each component of UAV including solar cells and airframe. Then, the iteration for subsystems is carried out with the help of Vortex Lattice Method(VLM) to optimize the aircraft configuration and the solar power system. It is demonstrated in simulations that the optimized design increases the flight time from 62 to 120 minutes when the solar power system is installed. Also, the associated dynamic analysis reveals that the designed small aircraft has the acceptable stability and controllability.

• 한국항공우주학회지
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• 제41권11호
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• pp.908-914
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• 2013

본 연구에서는 소형 태양광 무인항공기를 개발하여 비행시험을 수행하였다. 태양광 무인기는 날개에 설치된 태양전지로부터 전력을 생산하고, 생산된 전력의 일부를 비행동력으로 사용하며, 나머지를 일몰 후 비행을 위해 배터리에 저장을 한다. 태양광 무인항공기는 공기역학적으로 매우 효율이 높아야 하며, 구조적으로 경량이면서 고강도를 가져야 한다. 또한, 태양광 무인기의 전기추진시스템과 태양광 발전시스템도 높은 효율을 가져야 한다. 본 연구에서는 12시간 이상의 연속 비행을 위한 태양광 무인항공기 및 태양광 시스템을 개발하고, 그 성능을 파악하기 위해 비행시험을 수행하였다. 가을과 겨울철의 비행시험 결과 본 연구에서 개발한 태양광 무인항공기의 사계절 모두 12시간 이상의 연속비행이 가능함을 알 수 있었다.