• Aerospace Engineering and Technology
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• v.12 no.1
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• pp.54-63
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• 2013

In general, multiple hydraulic servo actuators are installed on one control surface of aero-dynamically highly loaded condition aircraft for redundancy management to satisfy flight control safety requirements. If motions of multiple actuators are not synchronized, control surface is deformed from its free stressed state. In result, force fight conditions are generated on each actuator due to restoration reaction force of deformed control surface. In addition, force fight is induced from severe initial rigging tolerance. Force fight condition of multiple actuators affects control accuracies and reduces operational life of actuators and control surface due to fatigue phenomenon. In this study, we designed controller using force feedback to reduce force fight of duplex servo actuation system.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.8
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• pp.678-687
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• 2012

The Fly-By-Wire(FBW) flight control system is essential to improve the stability and flying quality of the helicopter. Advanced aerospace companies, such as Bell-Sikorsky (USA) and NHI (European Consortium), have already applied the FBW flight control system to manufacture V-22 and NH-90 helicopters, respectively. This paper addresses the development of control law design using model inversion method improve the hover and low speed handling qualities of helicopter based on BO-105 model in 'Day' and 'Degraded visual environments(DVEs)' in accordance with ADS-33E-PRF. Design parameters are optimized to satisfy the handling qualities specification using Control Designer's Unified Interface (CONDUIT) commercial control law software. The result of the analysis based on CONDUIT and non-real time simulation in-house software, HETLAS (HElicopter Trim Linearization And Simulation) reveals that the provides an efficient mean to achieve Level 1 handling qualities.

• The tire
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• s.122
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• pp.32-38
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• 1986

타이어는 승용차를 비롯한 각종차량이나 항공기 등의 중요부품으로서 실로 광범위한 기능을 다하고 있는 것이다. 타이어는 무엇보다도 안전주행을 할 수 있어야 하고 자동차를 사용하는데 있어서의 경제성도 고려되어야 한다. 그리고 특히 승용차인 경우에는 차의 조종ㆍ안정성이나 진동ㆍ승차감ㆍ소음 등의 각종 요구에도 만족되어야 한다. 따라서 타이어가 이와같은 각종 요구조건을 만족시키고 있는가를 알기 위해서는 여러가지 시험을 통해서 평가하지 않으면 안된다. 또한 당연한 일이겠지만 이와같은 결과는 타이어 개발에 많이 활용되어야만 될 것이다. 타이어의 역할은 차량에 낀 다음부터 나타나게 되므로 타이어의 최종적인 평가는 실차시험에 따르는 것이 가장 좋으나, 시험의 능률, 경제성, 정밀도, 재현성 등의 여러가지 문제가 있기 때문에 실내시험으로 대체할 수 있는 제특성에 대해서는 가능한 한 여러가지의 실내시험기로 측정하는 방법을 택하고 있다. 그러나 자동차와의 조화로 나타나는 조종안정성이나 진동ㆍ소음: 승차감 등에 대해서는 실차시험으로 최종적인 평가ㆍ판정을 하는 수 밖에 없으므로 현재 세계의 많은 타이어 메이커들은 타이어 테스트코스를 설치하여 많은 시험차를 가지고 시험하고 있다. 따라서 여기서는 타이어의 시험이 어떠한 방법으로 이루어지고 있는지를 살펴보고자 한다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.6
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• pp.45-51
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• 2003

This paper presents a method to improve lateral stability of a four-seat canard aircraft, Velocity-173. Longitudinal stability of Velocity-173 is rather good, but lateral stability is relatively poor. A small panel which increases the area of vertical tail is designed and manufactured. In a design process, AAA(Advanced Aircraft Analysis) is used to predict the change in stability. Flight test is performed to validate the effect of a small panel attached under the vertical panel. Maximum likelihood estimation method is used to extract lateral controllability / stability derivatives from flight test data. This work validates the effect of a small panel attached under the vertical tail.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.6
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• pp.56-63
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• 2004

In this study, dynamic aeroelastic analyses of the canard with oscillating flap are conducted considering the effect of aerodynamic compressibility. The canard model considered herein is an all-movable type with a pitching axis on a canard-rotor-wing aircraft which was considered as one of the major UAV candidates under developing in Korea. The equivalent structural model is constructed based on the initial design data by the Korea smart UAV development center. Both the frequency and the time-domain aeroelastic analyses have been applied to practically conduct parametric studies on the effects of equivalent torsional stiffness. In the case of all-movable control surface with oscillating flap, the equivalent rotational stiffness of the pitch axes are important design parameters. The parametric results for the aeroelastic instability are practically presented.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.5
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• pp.109-118
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• 1996

An analysis of handling characteristics of a vehicle is performed for step and pulse steering input, which may be very useful in suspension design stage. Many developed computer programs for vehicle dynamics require test data of compliance effects for proto type car. Therefore, these programs are not suitable for automobile development stage. Using the raw design data of suspension and steering system, we analyze the vehicle behavior for step and pulse steering input with commercial multibody dynamics program, ADAMS. Simulated results are in good agreement with vehicle test results. Vehicle handling characteristics parameters which are very useful in automobile suspension design are evaluated from the analysis.

• Journal of Advanced Navigation Technology
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• v.18 no.4
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• pp.296-303
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• 2014

Recently a system is being required to replace ILS due to increasing air traffic. In this paper, Curved approach is applied to an airport where ILS approach cannot be applied due to its geographical condition and restricted aerospace condition, and verified by flight test. After analysing conditions of Tae-an airfield of Hanseo University with virtual ILS approach, airfield applicability was evaluated by Curved approach using by GPS. Normally simulation is performed after establishing approach procedure using electric map, but recently verification is being performed by flight test without simulation because accuracy and reliability are increased. In this paper, established procedure is verified modified by flight test with Pilot Test and Auto Pilot test and controllability and passenger's stability were also checked.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.173-179
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• 2005

In succession to previous study(A Study on the Limit of Anchor Dragging for Ship at Anchor sim I), the experiment of anchor dragging by ship handling simulator was performed to investigate the anchoring stability of ship at anchor in this study. The purpose of this experiment is to check the behavior charateristics of ship being dragged and the limit of anchor dragging for ship at anchor. A small tanker ship, which had been anchored in Jinhae Bay when the typhoon MAEMI passed on September 2003, was chosen as model ship for the experiment of anchor dragging and the result of experiment was confirmed to be very similar to the result of theoretical review and field report.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.6
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• pp.101-106
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• 2002

In a bank-to-turn(BTT) missile, if a 2-gimbaled seeker was stabilized using a 2-axis rate gyro mounted along its primary axis, the change of line of sight(LOS) measured by the seeker would be induced by rolling effects due to bank-to-turn(BTT) steering as well as an actual change. It is observed that the body-coupled effects in a homing loop of BTT missile are mainly concerned with the spurious target maneuver and the coupling due to the rate gyro misalignments. In this paper, we formulate a simple linear BTT homing loop model with seeker model including each body-coupling. With the model, we analyze the effects of the couplings on the homing loop stability, and propose a direct linear compensator for the coupling to recover the stability.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.2
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• pp.106-112
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• 2005

Modern versions of supersonic jet fighter aircraft have several different weapon loading configuration to support air-to-air combat and air-to-ground delivery of weapon modes. These various aircraft loading conditions could result in asymmetric configurations to the aircraft once delivered. These asymmetric configurations could result in decreased handling qualities for the pilot maneuvering, stability, control issues and aerodynamic performance of the aircraft. In order to eliminate or decrease these adverse impacts on the pilot's ability, development of T-50 flight control law attempts to control the aircraft in both longitudinal and lateral-directional axes. Especially, the design of the lateral-directional roll axis control laws, utilizing a simple roll rate feedback structure and gains such as F-16, is developed for the T-50 aircraft to meet the aircraft's design requirements. Consequently, it is found that the improved control law decreases the roll-off phenomenon in lateral axes during pitch maneuver.