• Title/Summary/Keyword: 우주비행의 자유

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Establishment of Real-time HILS Environment for Small UAV Using 6 D.O.F Motion Table (6자유도 모션테이블을 이용한 소형 무인항공기용 실시간 HILS 환경 구축)

  • Cha, Hyungkyu;Jeong, Jinseok;Shi, Hayoung;Yoon, Junseok;Kang, Beomsoo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.47 no.5
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    • pp.326-334
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    • 2019
  • Development of Small UAV using HILS (Hardware In the Loop Simulation) can be effectively used to improve the reliability of UAV (Unmanned Aerial Vehicle) while reducing cost and time. It is also possible to reduce the damage to people or property by simulating the malfunction of the Flight Control Computer (FCC) that may occur during the actual flight. For applying such HILS, a real-time simulation environment capable of providing an environment similar to an actual flight condition is required. In this paper, we constructed a real - time HILS environment for Small UAV using 6 D.O.F motion table. In order to link the 6 D.O.F motion table developed in the previous research with the HILS environment in real time, the motion algorithm was changed from the position control method to the velocity control method. Also, we implemented modeling of inverse kinematics model for command transmission in Matlab $Simulink^{(R)}$ and verified the action of motion table according to the simulation model.

Static Aeroelastic Analysis of Hingeless Rotor System in Hover Using Free-Wake Method (자유후류기법을 이용한 무힌지 로터 시스템의 정지비행시 정적 공탄성 해석)

  • Yoo, Seung-Jae;Lim, In-Gyu;Lee, In;Kim, Do-Hyung;Kim, Doeg-Kwan
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.36 no.2
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    • pp.156-162
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    • 2008
  • The static aeroelastic analysis of composite hingeless rotor blades in hover was performed using free-wake method. Large deflection beam theory was applied to analyze blade motions as a one-dimension beam. Anisotropic beam theory was applied to perform a cross-sectional analysis for composite rotor blades. Aerodynamic loads were calculated through a three-dimensional aerodynamic model which is based on the unsteady vortex lattice method. The wake geometry in hover was described using a time-marching free-wake method. Numerical results of the steady-state deflections for the composite hingeless rotor blades were presented and compared with those results based on two-dimensional quasi-steady strip theory and prescribed wake method. It was shown that wakes affect the steady-state deflections.

Trouble Shooting for Fully Automatic Flight Test of Small Scaled Tiltrotor UAV (축소형 틸트로터 무인기의 전자동 비행시험을 위한 문제해결과정)

  • Kang, Young-Shin;Park, Bum-Jin;Yoo, Chang-Sun;Koo, Sam-Ok;Lee, Jang-Ho
    • Aerospace Engineering and Technology
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    • v.8 no.1
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    • pp.1-9
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    • 2009
  • The ground integration test of Smart UAV has been performed according to the flight test plan. The flight test of full scaled model will be performed followed by 4 DOF ground rig test and a tethered hover test. Smart UAV is the first indigenous tiltrotor aircraft which can fly with fast cruise speed and take off or land vertically. In order to prove the flight control law of Smart UAV, the 40% scaled airplane was developed and have been tested. During flight test of small scaled model, many unique and unexpected problems occurred. After clearing these problems, fully automatic flight test was performed successfully. The experiences about many trouble shooting and resolving the problems would be basic material to avoid the unexpected but similar flight test problems hidden behind of the full scaled Smart UAV. This paper presents the detailed procedures of trouble shootings to solve the unique problems which occurred during the flight test of small scaled tiltrotor UAV.

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Flight Dynamics Mathematical Modeling of Quad Tilt Rotor UAM for Real-Time Simulation (쿼드 틸트 로터 UAM 실시간 비행 시뮬레이션을 위한 비행역학 수학적 모델링)

  • Hyunseo Kang;Nahyeon Roh;Do-young Kim;Min-jun Park
    • Journal of Aerospace System Engineering
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    • v.18 no.4
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    • pp.18-26
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    • 2024
  • This paper describes the results of a study on Generic Quad Tilt Rotor UAM aircraft, focusing on nonlinear mathematical modeling and the development of real-time simulation software. In this research, we designed a configuration for a Generic Quad Tilt Rotor eVTOL UAM aircraft based on NASA's UAM mission requirements. We modeled the aerodynamics using a database, the prop-rotor dynamics with a thrust database, and included a ground reaction and atmospheric model in the flight model. We defined the control concept for various modes(helicopter mode, transition mode, and airplane mode), derived tilt angle corridors, and formulated flight control requirements. The resultant real-time flight simulation software not only performs trim analysis for Tilt Rotor UAM aircraft but also predicts handling qualities, optimizes tilt angle scheduling based on dynamic characteristics, designs and validates flight control laws for helicopter, transition, and airplane modes, and facilitates flight training through simulator integration.

Missile Flight Condition for Slip-in Booster's Safe Separation (내삽형 부스터 안전 분리를 위한 비행 조건 연구)

  • Oh, Hyun-Shik;Lee, Ho-Il;Cho, Jin;Kim, Ik-Soo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.39 no.1
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    • pp.33-41
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    • 2011
  • A mathematical model of slip-in booster separation dynamics is described. A longitudinal 3-DOF(degree of freedom) 2-body dynamic model is developed to simulate the separation dynamics. Aerodynamic models of the missile and the exposed area of booster are built. And, gas generator pushing the booster out and internal channel pressure drop are modelled. To simulate the model, it is assumed that the missile can maintain the 1g level-fight condition during the separation. With this assumption, the interaction forces between missile and booster through the separation phases: phase 0: initial, phase 1: linear translation, and phase 2: free flight motion are defined. Using the simulation, missile flight conditions for slip-in booster`s safe separation, which can be represented by Mach vs. height envelope, are suggested.

Aerodynamic Simulation of Air-Launched Missiles from a Complete Helicopter (헬리콥터 전기체에서 발사되는 유도무기 공력 모사)

  • Lee, Hee-Dong;Kwon, Oh-Joon;Lee, Bum-Seok;Noh, Kyung-Ho
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.39 no.12
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    • pp.1097-1106
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    • 2011
  • Unsteady numerical analysis was performed to simulate air-launched missiles from a complete helicopter in hover by using an unstructured overset mesh flow solver coupled with a module of six degree-of-freedom motion of equations. The unsteady computations have been performed to obtain flow fields around the complete helicopter including main rotor, tail rotor, and fuselage equipped with multiple missiles, and six-DOF simulation has been performed to predict the behavior of the air-launched missile. The effects of the launching position and the missile thrust on the trajectory of the missile were investigated as well as the aerodynamic interference of the air-launched missile under the unsteady downwash produced by main rotor.

Application of Wind Tunnel Testing on the Dynamic Stability Derivatives of a Rocket Model (로켓 모델의 동안정미계수에 대한 풍동시험의 적용)

  • Cho, Hwan-Kee;Sung, Hong-Gye;Kim, Jin-Kon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.40 no.10
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    • pp.888-893
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    • 2012
  • This paper described the wind tunnel testing apparatus and technique to acquire the dynamic stability derivatives of large slenderness ratio air vehicle such as the guided missiles or rockets. There have been few difficulties in conducting wind tunnel testing for slender long rocket due to the size limitation of the test section size and the installation of oscillation equipments. In this study, the dynamic stability balance was used as the wind tunnel technique for obtaining the dynamic stability derivatives. Through the wind tunnel testing, the experimental apparatus for slender air vehicle's oscillation is established. The measured data showed that it is possible to acquire the dynamic stability derivatives of large slenderness ratio rocket, properly.

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.

Optimal Soft Landing Guidance and Attitude Control for Reusable Launch Vehicles (재사용 발사체를 위한 최적 연착륙 유도 및 자세 제어 연구)

  • Jeon, Ho-Young;Cho, Jun-Hyon;Kim, Jong-Han
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.50 no.4
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    • pp.251-257
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    • 2022
  • We formulated the convex optimization based minimum energy soft landing problem for reusable launch vehicles, and obtained the minimum time trajectory via the bisection search. In order to implement the the optimal guidance command and complete the flight control architectures on the soft landing stage, we designed the classical attitude control loops, and formulated and solved the optimal actuator allocation problem. The obtained soft landing guidance performance was analyzed via nonlinear 6-DOF simulation.

Assessment of Flight Control Performance based on the Ground Test Results of Smart UAV (스마트 무인기의 지상시험을 통한 비행제어 성능분석)

  • Kang, Young-Shin;Park, Bum-Jin;Yoo, Chang-Sun;Kim, Yu-Shin;Koo, Sam-Ok
    • Aerospace Engineering and Technology
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    • v.9 no.1
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    • pp.1-8
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    • 2010
  • The tilt-rotor Smart UAV(Unmanned Air Vehicle) has been developed by KARI(Korea Aerospace Research Institute) for civil purposes. In order to prove the reliabilities of total system of Smart UAV, the series of ground tests were performed including system interface test, aircraft HILS(Hardware In the Loop Simulation) Test, ground power test, 4-DOF (Degrees of Freedom)rig test, and tethered hover test. Many unexpected problems occurred at each ground test. With clearing these problems, the total Smart UAV systems were matured and the airworthiness was proven enough. After complete of additional ground test proposed by FRRB(Flight Readiness Review Board), the first flight test will be performed in this year. This paper presents the procedures and the analysis results of the ground tests for the tilt-rotor Smart UAV.