• Title/Summary/Keyword: Model Helicopter

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Satellite data validation system using RC helicopter

  • Honda, Yoshiaki;Kajiwara, Koji
    • Proceedings of the KSRS Conference
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    • 2002.10a
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    • pp.746-749
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    • 2002
  • This paper is introducing a radio control helicopter as a new platform of ground truth measurement. This helicopter is normally used for spraying an agricultural chemical. It can do pinpoint hovering and programing flight using DGPS etc., A spectrometer with dual port can measure ground surface and white reference plate at the same time. And it can also take digital images by digital camera. It is needed to collect ground reflectance information as satellite sensor footprint size for satellite data validation. Generally it is possible to get such ground reflectance by an airplane measurement. But it is high cost and not so easy to make a measurement by airplane. Developed validation system can provide such ground reflectance in low cost and easy.

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Determination of the Principal Directions of Composite Helicopter Rotor Blades with Arbitrary Cross Sections

  • Oh, Taek-Yul;Choi, Myung-Jin;Yu, Yong-Seok;Chae, Kyung-Duck
    • Journal of Mechanical Science and Technology
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    • v.14 no.3
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    • pp.291-297
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    • 2000
  • Modern helicopter rotor blades with non-homogeneous cross sections, composed of anisotropic material, require highly sophisticated structural analysis because of various cross sectional geometry and material properties. They may be subjected by the combined axial, bending, and torsional loading, and the dynamic and static behaviors of rotor blades are seriously influenced by the structural coupling under rotating condition. To simplify the analysis procedure using one dimensional beam model, it is necessary to determine the principal coordinate of the rotor blade. In this study, a method for the determination of the principal coordinate including elastic and shear centers is presented, based upon continuum mechanics. The scheme is verified by comparing the results with confirmed experimental results.

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Self-Noise Prediction from Helicopter Rotor Blade (헬리콥터 로터 블레이드의 자려소음 예측)

  • Kim, Hyo-Young;Ryu, Ki-Wahn
    • Journal of Aerospace System Engineering
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    • v.1 no.1
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    • pp.73-78
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    • 2007
  • Self-noise from the rotor blade of the UH-1H Helicopter is obtained numerically by using the Brooks' empirical noise model. All of the five noise sources are compared with each other in frequency domain. From the calculated results the bluntness noise reveals dominant noise sources at small angel of attack, whereas the separation noise shows main noise term with gradually increasing angel of attack. From the results of two different tip Mach numbers with the change of angel of attack, the OASPLs at M = 0.8 show about 15dB larger than those at M = 0.4.

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Design of Lateral SCAS based on H for Tilt Rotor Aircraft (H 기반 틸트로터 항공기 횡방향 SCAS 설계)

  • Lee, Jangho;Yoo, Changsun;Walker, Daniel J.
    • Journal of Aerospace System Engineering
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    • v.2 no.3
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    • pp.1-6
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    • 2008
  • The tilt rotor aircraft has the flight characteristics which takes off vertically like a helicopter and flies forward like an airplane. Especially, the transition process from a helicopter to an airplane mode requires not only the mixing of control inputs but also the stability and controllability augmentation system(SCAS) in order to keep the safe flight because there are compound flight dynamic characteristics of a helicopter and an airplane including non-linearity, uncertainty. This paper describes the design of SCAS in a lateral motion for the tilt rotor aircraft based on the $H_{\infty}$ control method, which was performed from mathematical model with weighting matrix based on the relationship between the $H_{\infty}$ norm and the sensitivity function. Through simulation analysis for the controller designed on the $H_{\infty}$ control theory, it was shown that this method may be applied to the control design of the tilt rotor aircraft.

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Hot Forging Analysis of Rotor Grip with Titanium Alloy for Unmanned Helicopter (무인헬기용 티타늄 합금 로터 그립의 열간성형해석)

  • Lee, Seong-Chul;Kong, Jae-Hyun;Hur, Kwan-Do
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.10 no.2
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    • pp.96-103
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    • 2011
  • Rotor grip is used as a component of rotor system in unmanned helicopter. Instead of usual machining, hot forging process has been considered to improve its proof stress against repeated loading conditions and crash in the farm-field. Die design and forming analysis have been performed according to the conditions such as billet volume, flash, cavity filling, and the distribution of damage during the forming by using FE analysis. In the results of analysis, the possibility of structural failure in the model has not been found because its maximum effective stress is much lower than yield strength of the titanium alloy. In the forging die design, flash has been allowed because of low production in the industrial field. Preform design was studied by using FE-analysis, and its optimal dimension was obtained in the hot forging of rotor grip with titanium alloy.

Attitude Control of Helicopter Simulator System using A Hybrid GA-PID WAVENET Controller (Hybrid GA-PID WAVENET 제어기를 이용한 모형 헬리콥터 시스템의 자세 제어)

  • 박두환;지석준;이준탁
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.53 no.6
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    • pp.433-439
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    • 2004
  • The Helicopter Simulator System is non-linear and complex. Futhermore, because of absence of its accurate mathematical model, it is difficult to control accurately its attitudes such as elevation angle and azimuth one. Therefore, we proposed a Hybrid GA-PID WAVENET(Genetic Algorithm Proportional Integral Derivative Wavelet Neural Network)control technique to control efficiently these angles. The proposed Hybrid GA-PID WAVENET is made through the following process. First, the WAVENET fundamental functions are defined. And their dilation and translation values are adjusted by GA to construct the optimal WAVENET controller. Secondly, the proportional, integral, and derivative gain coefficients of PR controller are tuned optimally. Finally, WAVENET controller which has a good transient characteristic and GA-PE controller which has a good steady state characteristic is adequately combined in hybrid type. Through the computer simulations, it is proved that the Hybrid GA-PE WAVENET control technique has a more excellent dynamic response than PID control technique and GA-PID one.

Structural Optimum Design of Composite Rotor Blade (복합재 로터 블레이드의 구조 최적설계)

  • Park, Jung-Jin;Lee, Min-Woo;Bae, Jae-Sung;Lee, Soo-Yong;Kim, Seok-Woo
    • Journal of Aerospace System Engineering
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    • v.1 no.3
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    • pp.26-31
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    • 2007
  • This paper addresses a method for structural optimum design of composite rotor blade. The basic model of a composite helicopter main rotor blade is designed and its parameters determining the structural/dynamic properties are studied. Through the investigation of flap/lag/torsional stiffness, the structural properties of the model are analyzed. In this study, helicopter rotor blades are analyzed by using VABS. The computer program VABS (Variational Asymptotic Beam Section Analysis) uses the variational asymptotic method to split a three-dimensional nonlinear elasticity problem into a two dimensional cross-sectional analysis and a one-dimensional nonlinear beam problem. This is accomplished by taking advantage of certain small parameters inherent to beam-like structures. In addition, the rotational stability of the blade is estimated by the frequency diagram from FE analysis(MSC.Patran/Nastran) to understand its vibrational property. From the result, design parameters to determine and optimize the properties of the model are presented.

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A Model of a Mechanical Flight-Control System for Simulating Control Authority Switching of a Helicopter Technical Demonstrator (헬리콥터 기술시범기의 비행제어 조종권 전환 모의를 위한 기계식 조종장치 모델 설계 연구)

  • Yang, Chang Deok
    • Journal of Aerospace System Engineering
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    • v.11 no.2
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    • pp.23-29
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    • 2017
  • Since the flight-control system is critical for the safety of an aircraft, a fail-safe system is needed in a flight demonstrator used to test a new flight-control system. A backup control system is also needed to ensure safety in using a mechanical flight-control system. This paper presents a development of an MFCS (Mechanical Flight Control System) model for simulating control authority switching of a helicopter technical demonstrator, as well as the results of evaluating the developed MFCS model.

Design of an Elastomeric Bearing for a Helicopter Rotor Hub by Non-linear Finite Element Method (비선형 유한요소법을 이용한 헬리콥터 로터허브용 탄성체베어링 설계)

  • Kim, Hyun-Duk;Yoo, Si-Yoong;Park, Jung-Sun
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.38 no.6
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    • pp.612-619
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    • 2010
  • In this paper, an elastomeric bearing for a helicopter rotor hub is designed using nonlinear finite element method. The elastomeric bearing is the main component of the helicopter rotor hub that acts as a hinge to three motions(flapping, lagging and pitching) of rotor blade. The elastomeric bearing consists of rubber and metal plates. The stiffness design of the elastomeric bearing is important because elastic deformation of rubber is served to hinge. Accordingly, the elastomeric bearing is designed to satisfy the stiffness requirements for rotor hub bearing. In this study, a FE model generation algorithm is developed and stiffness characteristic of a rubber plate is analyzed for an efficient design of the spherical elastomeric bearing. It is proven that the elastomeric bearing satisfies stiffness requirements of the spherical bearing for a helicopter rotor hub.

Semi-Active Control of Helicopter Landing Gear using Magneto-Rheological Damper (MR 댐퍼를 이용한 헬기 착륙장치 반능동제어)

  • Hwang, Jae-Up;Hwang, Jae-Hyuk;Bae, Jae-Sung;Hyun, Young-O;Lim, Kyoung-Ho;Kim, Doo-Man;Kim, Tae-Wook
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.36 no.4
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    • pp.346-351
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    • 2008
  • In this paper, the semi-active control of a helicopter landing gear using magneto -rheological(MR) damper is studied. A dynamic model of the MR damper is formulated by incorporating magnetic field-dependent Bingham properties of the MR fluid. The electromagnet of the MR damper is designed and its magnetic field is analyzed using a commercial finite element code. The damping characteristics of MR damper by changing the intensity of the magnetic field are investigated and the dynamic responses of the helicopter landing gear with MR damper are simulated. The semi-active control of the helicopter landing gear is simulated by implementing a sky-kook control algorithm and its performance is evaluated comparing to the passive control.