• Title/Summary/Keyword: freedom of flight

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Photogrammetric Techniques for Safe Separation Flight Test (안전분리 비행시험을 위한 사진계측 기법)

  • Kim, Sang-Jin;You, Heung-Cheol;Reu, Taekyu;Park, Jeong Ho
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.41 no.8
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    • pp.673-679
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    • 2013
  • Photogrammetric techniques were used to analyze separation characteristics of store in safe separation flight test. In this analysis, we used single camera method to analyze 6 degrees of freedom of separated store. We established instrumentation requirements based on theoretical background of photogrammetry and guidelines of MIL-HDBK-1763. We applied the photogrammetry to flight test and extracted separation trajectory. We empirically estimated the input variables uncertainties of photogrammetry and its effects on separation trajectory. Using this trajectory which includes the photogrammetric error, we analyzed the safety of separation.

Risk Assessment of a Drone Under the Gust and its Precise Flight Simulation (드론의 외풍 환경 비행 안전성 평가 및 정밀 시뮬레이션)

  • Lee, DongYeol;Park, SunHoo;Shin, SangJoon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.50 no.3
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    • pp.173-180
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    • 2022
  • The operation and transportation environment for an unmanned aerial vehicle will be completely different from those for the conventional air and ground transportation. The requirement for a traffic management system for its safe operation has been emerging. Accordingly, investigation is being conducted to analyze the danger that unmanned aerial vehicle may encounter during the flight and to provide the countermeasure by the simulation. When the drones operate in an urban environment, they may be affected by the wind around the building. Thus it is essential to predict the influence of the gust and analyze the resulting risk. In this paper, a method for evaluating the safety for a flight mission under the gust is suggested. By using the precise 6-degree-of-freedom flight simulation that is capable of simulating the gust condition, possible deviation from the pre-planned flight path in terms of the attitude orientation will be predicted. A method of quantifying the probability of the flight mission failure will also be presented.

Modelling of Fixed Wing UAV and Flight Control Computer Based Autopilot System Development for Integrated Simulation HILS Environment (고정익 UAV 모델링 및 비행조종컴퓨터 기반 오토파일럿 통합 시뮬레이션 HILS 환경 구축)

  • Kim, Lamsu;Lee, Dongwoo;Lee, Hohyeong;Hong, Suwoon;Bang, Hyochoong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.50 no.12
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    • pp.857-866
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    • 2022
  • Fixed-wing UAVs have long endurance and range capabilities compared to other aerial platforms. These advantages led fixed-wing UAVs to become a popular platform for reconnaissance missions in the military. In this research, we modeled fixed-wing UAVs, including the landing gear model and developed a guidance and control system for flight control computers to construct a HILS environment. We also developed an autopilot system that includes automated take-off, cruise, and landing control for UAVs. We also retrived the Aerodynamic coefficients an UAV using Datcom and AVL software and used them for 6 degrees of freedom modeling. The Flight control computer calculates guidance commands using the Carrot chasing guidance law after distinguishing the condition of the UAV based on 16 pre-defined flight modes and calculates control inputs using Nonlinear Dynamic Inversion (NDI) control scheme. We used RTNngine to integrate the Simulink model and flight control computer for HILS environment formulation.

Legal implications of missile test moratorium by the North Korea (북한의 미사일발사 실험 유예조치의 법적 의의)

  • Shin, Hong-Kyun
    • The Korean Journal of Air & Space Law and Policy
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    • v.22 no.1
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    • pp.105-123
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    • 2007
  • The launching of the Taepo-dong 1 on 31 August 1998 by the North Korea was the first case where the diplomatic protests was made against the flight, the purpose of which, the launching State claimed, consisted in space exploration and use. It is the principle regarding the freedom of space exploration and use, as included in the international treaty, that is relevant in applying the various rules and in defining the legal status of the flight. Its legal status, however, was not actually taken into account, as political negotiations leading to the test moratorium has been successful until present day in freezing the political crisis. This implies that the rules of the law lack the validity and logic sufficient in dictating the conduct of the States. This case shows that, in effect, it is not the rule but the politics that is to govern the status of the flight.

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Legal implications of missile test moratorium by the North Korea (북한의 미사일발사 실험 유예조치의 법적 의의)

  • Shin, Hong-Kyun
    • The Korean Journal of Air & Space Law and Policy
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    • no.spc
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    • pp.87-104
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    • 2007
  • The launching of the Taepo-dong 1 on 31 August 1998 by the North Korea was the first case where the diplomatic protests was made against the flight, the purpose of which, the launching State claimed, consisted in space exploration and use. It is the principle regarding the freedom of space exploration and use, as included in the international treaty, that is relevant in applying the various rules and in defining the legal status of the flight. Its legal status, however, was not actually taken into account, as political negotiations leading to the test moratorium has been successful until present day in freezing the political crisis. This implies that the rules of the law lack the validity and logic sufficient in dictating the conduct of the States. This case shows that, in effect, it is not the rule but the politics that is to govern the status of the flight.

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Dynamic Characteristics Analysis of Landing Gear that Consider 6-Degree of Freedom of Helicopter (6자유도를 고려한 회전익 항공기 착륙장치의 동특성 해석)

  • Park, Wansoo;Hwang, Jaeup;Hyun, Youngho;Hwang, Jaehyuk;bae, Jaeseoung;Kim, Taewook
    • Journal of Aerospace System Engineering
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    • v.2 no.1
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    • pp.1-6
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    • 2008
  • In this paper, full body modeling and analysis of nose and main landing gear's characteristics of a helicopter are performed using the dynamics analysis program ADAMS. Also, when land limiting about helicopter body's degree-of-freedom, compared the characteristics. In the case of helicopter, because there are a lot of dangerous missions under flight condition that is disadvantageous than fixed wing airplane, need more detailed research for a helicopter.

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Transformed Augmented Cucker-Smale Model with Mahalanobis Distance and Statistical Degrees of Freedom for Improving Efficiency of Flocking Flight System (시스템의 성능 향상을 위해 마할라노비스 거리와 자유도를 이용하여 변형시킨 쿠커-스메일 모델)

  • Jung, Jae-Hwi
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.48 no.8
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    • pp.573-580
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    • 2020
  • One of challengeable problems of multi-agent systems is a positioning control. Augmented Cucker-Smale model is using for controlling position and velocity of the multi-agent system. The original model applies same coefficients to all agents in same group, so that does not consider characteristic of each agent. To enhance performance of the original model, this paper transforms original coefficients to Mahalanobis distance coefficients that reflects an initial distribution of multi-agent systems and applies statistical degrees of freedom. This paper not only confirms tendency of enhanced performance of the suggested model by using monte-carlo simulation, but also additionally compares trajectory of the original model with the suggested model to confirm coefficients of Mahalanobis distance performing correctly.

A Robust Extended Filter Design for SDINS In-Flight Alignment

  • Yu, Myeong-Jong;Lee, Sang-Woo
    • International Journal of Control, Automation, and Systems
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    • v.1 no.4
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    • pp.520-526
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    • 2003
  • In the case of a strapdown inertial navigation system (SDINS) with sizeable attitude errors, the uncertainty caused by linearization of the system degrades the performance of the filter. In this paper, a robust filter and various error models for the uncertainty are presented. The analytical characteristics of the proposed filter are also investigated. The results show that the filter does not require the statistical property of the system disturbance and that the region of the estimation error depends on a freedom parameter in the worst case. Then, the uncertainty of the SDINS is derived. Depending on the choice of the reference frame and the attitude error state, several error models are presented. Finally, various in-flight alignment methods are proposed by combining the robust filter with the error models. Simulation results demonstrate that the proposed filter effectively improves the performance.

Nonlinear Adaptive Flight Control Using Neural Networks and Backstepping (신경회로망 및 Backstepping 기법을 이용한 비선형 적응 비행제어)

  • Lee, Taeyoung;Kim, Youdan
    • Journal of Institute of Control, Robotics and Systems
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    • v.6 no.12
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    • pp.1070-1078
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    • 2000
  • A nonlinear adaptive flight control system is proposed using a backstepping controller with neural network controller. The backstepping controller is used to stabilize all state variables simultaneously without the two-timescale assumption that separates the fast dynamics, involving the angular rates of the aircraft, from the slow dynamics which includes angle of attack, sideslip angle, and bank angle. It is assumed that the aerodynamic coefficients include uncertainty, and an adaptive controller based on neural networks is used to compensate for the effect of the aerodynamic modeling error. It is shown by the Lyapunov stability theorem that the tracking errors and the weights of neural networks exponentially converge to a compact set. Finally, nonlinear six-degree-of-freedom simulation results for an F-16 aircraft model are presented to demonstrate the effectiveness of the proposed control law.

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Design of hovering flight controller for a model helicopter

  • Shim, Hyeoncheol;Lee, Ho-Eun;Park, Hyunsik;Lee, Kyo-Il
    • 제어로봇시스템학회:학술대회논문집
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    • 1992.10b
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    • pp.344-348
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    • 1992
  • This paper describes a procedure to design a hovering flight controller for a model helicopter using LQG theory. Parameters of the model helicopter in hover are obtained using direct measurements and calculations proposed by other research. A feedback co is by using digital LQG theory. First, a full state feedback controller is designed to the discretized system taking desirable transient response and other assumptions into account. Then a full-state estimator is designed and revised until desirable response is obtained while global stability is maintained. Performance of the controller is tested by computer simulations. Experiments have been performed using a 3-degree-of-freedom gimbal that holds the model helicopter, and the controller exhibited stable hover capability.

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