• Title/Summary/Keyword: Unmanned Aerial Vehicles (UAV)

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Development and Flight Test of Variable-Camber and Variable-Chord Morphing Flap (가변캠버 가변시위 모핑 플랩의 개발 및 비행실험)

  • Jihyun Oh;Jae-Sung Bae;Hyun Chul Lee
    • Journal of Aerospace System Engineering
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    • v.18 no.4
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    • pp.34-42
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    • 2024
  • This study developed a morphing technology applicable to unmanned aerial vehicles (UAVs) with diverse flight characteristics. Existing morphing technologies require additional mechanisms and driving devices, posing challenges in constructing features such as ribs and spars within the wing structure, leading to structural instability. To address this, we developed a Variable-Camber and Variable-Chord (VCC) morphing flap that could maintains a continuously transforming surface during deformation, altering both camber shape and chord length simultaneously. Furthermore, we conducted design and fabrication of UAV wings incorporating these morphing flaps, ensuring structural stability by developing specialized shapes. Furthermore, structural experiments were conducted to simulate flight loads, followed by actual flight tests to validate performances of both morphing mechanism and wings. Finally, wind tunnel tests were conducted to compare results with aerodynamic analysis, confirming the effective applicability of this morphing technology.

Accuracy Analysis of Low-cost UAV Photogrammetry for Corridor Mapping (선형 대상지에 대한 저가의 무인항공기 사진측량 정확도 평가)

  • Oh, Jae Hong;Jang, Yeong Jae;Lee, Chang No
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.36 no.6
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    • pp.565-572
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    • 2018
  • Recently, UAVs (Unmanned Aerial Vehicles) or drones have gained popularity for the engineering surveying and mapping because they enable the rapid data acquisition and processing as well as their operation cost is low. The applicable fields become much wider including the topographic monitoring, agriculture, and forestry. It is reported that the high geospatial accuracy is achievable with the drone photogrammetry for many applications. However most studies reported the best achievable mapping results using well-distributed ground control points though some studies investigated the impact of control points on the accuracy. In this study, we focused on the drone mapping of corridors such as roads and pipelines. The distribution and the number of control points along the corridor were diversified for the accuracy assessment. In addition, the effects of the camera self-calibration and the number of the image strips were also studied. The experimental results showed that the biased distribution of ground control points has more negative impact on the accuracy compared to the density of points. The prior camera calibration was favored than the on-the-fly self-calibration that may produce poor positional accuracy for the case of less or biased control points. In addition, increasing the number of strips along the corridor was not helpful to increase the positional accuracy.

A study on mandatory insurance for aircraft operators (항공보험 가입의무에 관한 연구)

  • Lee, Chang-Jae
    • The Korean Journal of Air & Space Law and Policy
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    • v.33 no.2
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    • pp.169-197
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    • 2018
  • The purpose of this study is to present a reasonable and concrete standard for the Korean aviation insurance compulsory subscription system. Through this, we aim to improve the current revision of laws and regulations, and ultimately create an environment in which the safety and property of the Korean people who use aircraft with appropriate aviation insurance can be secured. In particular, by reviewing the aviation business law and its new laws and regulations enacted in 2017, the legislative improvement direction of aviation insurance will be proposed. In order to maintain the continuous growth of the air transportation industry and to make amicable compensation for the victims, considering the characteristics of the total accident, instantness, and giganticness of air accidents in which a lot of people and property are lost in the event of an accident, adequate insurance coverage is essential. In this respect, the compulsory insurance to amend the principle of freedom of contract, which is the great principle of the modern judicial system, will be persuasive. However, in comparison with foreign legislation, the legal provisions on Korea's obligation to comply with aviation insurance need to be revised around the following issues: First, it is reasonable to enforce the regulation of the mandatory aviation insurance by legislation from the Congress not by administrative regulations. Because it will force the monetary obligations of the individual such as common air carriers. Second, our law regulations respond to various kinds of air damages by using the phrase "limit of liability stipulated in international conventions". However, as we have seen in the text, the range of compensation are various according to the use of legal instruments in international conventions such as the Montreal Convention, which governs the compensation of passengers for damages to passengers today. Third, in countries with narrow territories, such as Korea, there are big differences in flying time and insurable risk between domestic and international transportation. Therefore, it is necessary to divide domestic transportation and international transportation even in the obligation to join the insurance. This dual discipline has the advantage for rookies in air carrier market who mainly start their business from domestic service. Fourth, according to Korean law, the regulations of automobile loss insurance is applicable to the aviation mandatory insurance of unmanned aerial vehicle accident which is lack of persuasion. In the future, it will be appropriate to discipline insurance for unmanned aerial vehicles with unlimited potential for development from a long-term perspective.