• International Journal of Aeronautical and Space Sciences
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• 제13권3호
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• pp.267-281
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• 2012

This paper reviews the flight mechanics and control of birds and bird-size aircraft. It is intended to fill a niche in the current survey literature which focuses primarily on the aerodynamics, flight dynamics and control of insect scale flight. We review the flight mechanics from first principles and summarize some recent results on the stability and control of birds and bird-scale aircraft. Birds spend a considerable portion of their flight in the gliding (i.e., non-flapping) phase. Therefore, we also review the stability and control of gliding flight, and particularly those aspects which are derived from the unique control features of birds.

• 한국항공우주학회지
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• 제49권8호
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• pp.681-688
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• 2021

본 논문은 시험발사체의 비행궤적 및 낙하점 분산 분석에 대해 다룬다. 2018년 11월의 시험발사체 비행시험 전/후에 수행한 비행궤적 및 낙하점 분산 분석 과정을 설명하고 비행시험 결과와의 비교를 통해 분산 분석 방안이 적절하였음을 보인다. 발사체의 궤적 및 낙하점 분산은 발사체 성능 오차 요인 및 대기권에서의 바람 영향을 고려한 6자유도 몬테카를로 시뮬레이션을 통해 이루어진다. 이와 같이 사전에 분석한 결과를 토대로 비행시험 전에 낙하 안전 영역을 설정한다. 결과적으로, 시험발사체는 사전에 분석한 궤적 및 낙하점 분산 범위 내에서 안전하게 비행하였다.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2004년도 한국우주과학회보 제13권2호
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• pp.364-367
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• 2004

This paper presents the flight software of KoDSat (KSLV-l Demonstration Satellite) which performs demonstrating the KSLV-l (Korea Space Launch Vehicle-l)'s satellite launch capability. The KoDSat Flight Software executes in a single-processor, multi-function flight computer on the spacecraft, the OBC (On Board Computer). The flight software running on the single processor is responsible for all real-time processing associated with: processor startup and hardware initialization, task scheduling, RS422 handling function, command and data handling including uplink command and down-link telemetry, attitude determination and control, battery state of charge monitoring and control, thermal control processing.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.513-520
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• 2004

A steady-state/transient performance simulation model was newly developed for the propulsion system of the CRW (Canard Rotor Wing) type UAV (Unmanned Aerial Vehicle) during flight mode transition. The CRW type UAV has a new concept RPV (Remotely Piloted Vehicle) which can fly at two flight modes such as the take-off/landing and low speed forward flight mode using the rotary wing driven by engine bypass exhaust gas and the high speed forward flight mode using the stopped wing and main engine thrust. The propulsion system of the CRW type UAV consists of the main engine system and the duct system. The flight vehicle may generally select a proper type and specific engine with acceptable thrust level to meet the flight mission in the propulsion system design phase. In this study, a turbojet engine with one spool was selected by decision of the vehicle system designer, and the duct system is composed of main duct, rotor duct, master valve, rotor tip-jet nozzles, and variable area main nozzle. In order to establish the safe flight mode transition region of the propulsion system, steady-state and transient performance simulation should be needed. Using this simulation model, the optimal fuel flow schedules were obtained to keep the proper surge margin and the turbine inlet temperature limitation through steady-state and transient performance estimation. Furthermore, these analysis results will be used to the control optimization of the propulsion system, later. In the transient performance model, ICV (Inter-Component Volume) model was used. The performance analysis using the developed models was performed at various flight conditions and fuel flow schedules, and these results could set the safe flight mode transition region to satisfy the turbine inlet temperature overshoot limitation as well as the compressor surge margin. Because the engine performance simulation results without the duct system were well agreed with the engine manufacturer's data and the analysis results using a commercial program, it was confirmed that the validity of the proposed performance model was verified. However, the propulsion system performance model including the duct system will be compared with experimental measuring data, later.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.367-371
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• 2004

This paper describes development of automatic flight control system for an unmanned target drone which is operated by Korean army as for anti-air gun shooting training. Current target drone is operated by pilot control of on-board servo motor via remote control system. Automatic flight control system for the target drone greatly reduces work load of ground pilot and can increase application area of the drone. Most UAVs being operated now days use high-priced sensors as AHRS and IMU to measure the attitude, but those are costly. This paper introduces the development of low-cost automatic flight control system with low-cost sensors. The integrated automatic flight control system has been developed by integrating combining power module, switching module, monitoring module and RC receiver as an one module. The performance of automatic flight control system is verified by flight test.

• International Journal of Aeronautical and Space Sciences
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• 제10권1호
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• pp.30-36
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• 2009

Many formation guidance laws have been proposed for VAV formation flight. Since most autonomous formation flight methods require various active communication links between the vehicles to know motion information of other vehicles, damage to the receiver or the transmitter and communication delay are critical problem to achieve a given formation flight mission. Therefore, in this point of view, the method that does not need an inter-vehicle communication is preferred in the autonomous formation flight. In this paper, we first summarize the formation guidance law without an inter-vehicle communication using feedback linearization and sliding mode control proposed in previous study. We also propose the modified formation guidance law with robust disturbance observer, which can provide significantly better performance than previously mentioned guidance law in case that other vehicles maneuver with large accelerations. The robust disturbance observer can estimate uncertainties generated by acceleration of leader vehicle. By eliminating the uncertainties using the estimated uncertainties, VAVs are able to achieve the tight formation flight. The performance of the proposed approach is validated by numerical simulations.

• 한국항행학회논문지
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• 제16권4호
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• pp.571-577
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• 2012

본 논문에서는 소형 무인항공기에 대한 비행제어 시스템을 동적 보상기를 이용하여 설계하였다. 제안된 제어 시스템은 정상상태 오차를 줄이면서 과도응답 특성을 개선하여 고도 변화 및 목표점 통과 명령에 대해 비행 안정성을 확보하고자 하였다. 제안된 비행 제어기는 내부 루프와 외부 루프의 이중 구조로 구성되며, 내부 루프는 PD 제어기를 사용하여 과도응답을 개선하도록 하며 외부 루프는 동적 보상기를 사용하여 과도 응답 및 정상 상태 오차를 개선하도록 하였다. 고도 추종 및 목표점을 통과하도록 하는 비행실험을 통하여 제안된 기법의 성능을 평가하였다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.2
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• pp.273-278
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• 2006

In order to use a GPS antenna for launch vehicles, it should be installed on the skin of the vehicle and be able to normally receive the live GPS signals during the vehicle's full flight mission. The GPS antenna on the surface of the launch vehicle is, however, exposed to higher temperature than inner equipments of the vehicle due to aerodynamic heating generated during the flight. Test specification of the GPS antenna for qualification of hot-temperature is determined to $+95^{\circ}C$ that is higher than inner components by $25^{\circ}C$. Test results in this paper show that the GPS antenna normally operates under the above environment.

• 항공우주기술
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• 제7권2호
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• pp.31-37
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• 2008

항공기의 변수 추정을 위해서는 비행시험을 통해 얻어진 데이터를 이용해야한다. 비행 시험의 문제점으로 비행중에는 데이터를 재조정하기가 힘들다. 이러한 점을 감안하여 본 논문에서는 변수추정을 위한 비행시험을 대신해서 선회 비행 데이터를 사용하여 주파수영역에서 변수를 추정하는 상용화된 변수추정프로그램(CIFER)으로 스마트 무인기 40% 축소기의 동적 파라미터를 추정하였다.

• 제어로봇시스템학회논문지
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• 제20권12호
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• pp.1217-1224
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• 2014

This paper presents a modified track guidance algorithm for formation flight of multiple UAVs. The suggested guidance algorithm is the spatial version of the first order dynamic characteristics for a time-dependent system so the algorithm is able to generate a path without overshoot to track the desired line. A crucial design parameter is a spatial constant that controls the shape of the convergence to an assigned flight path similarly to a time constant. Reference flight trajectories are designed based on a two-dimensional vehicle model, and the performance of the proposed guidance law is verified by numerical simulation using rigid body UAV dynamics with MATLAB/Simulink Aerosim Blockset.