• International Journal of Aeronautical and Space Sciences
• /
• 제9권1호
• /
• pp.121-128
• /
• 2008

This paper describes the modeling and autopilot design procedure of a Blended Wing-Body(BWB) UAV. The BWB UAV is a tailless design that integrates the wing and the fuselage. This configuration shows some aerodynamic advantages of lower wetted area to volume ratio and lower interference drag as compared to conventional type UAV. Also, BWB UAV may be increase payload capacity and flight range. However, despite of these benefits, this type of UAV presents several problems related to flying qualities, stability, and control. In this paper, the detailed modeling procedure of BWB UAV and stability analysis results using the linearized model at trim condition are represented. Finally, we designed the autopilot of BWB UAV based on a simple control allocation scheme and evaluated its performance through nonlinear simulation.

• 한국수소및신에너지학회논문집
• /
• 제22권6호
• /
• pp.819-826
• /
• 2011

The proton exchange membrane fuel cell (PEMFC) is regarded as the most promising alternative power sources for unmanned aerial vehicle (UAV) due to its high energy density and silent operation. Since there are many load changes during UAV flight, thermal management is one of the important factor for the performance of PEMFC. In order to reduce the UAV weight for the stable operation of UAV, thermal management system (TMS) studied in this work does not use the fan but use the air flowing into UAV by UAV flight. In order to develop the passive type heat exchanger (HEX) for 1kW PEMFC, four types of HEXs are fabricated and their cooling performances are compared. The parametric study on the cooling performance of HEXs has performed with the variation of operating parameters such as mass flow rates and inlet temperature of air and coolant. Type 4 has the best performance in every case. This study can be helpful to achieve the optimal design of HEX for PEMFC powered UAV.

• 한국추진공학회지
• /
• 제8권4호
• /
• pp.76-83
• /
• 2004

CRW Tyre UAV 추진시스템은 수직으로 이착륙이 가능하고 고정익으로 고속 전진 비행이 가능한 개념으로 설계되었다. 이를 위해 추진시스템은 이착륙 시에는 로터를 구동시켜 수직으로 비행하고 고속 비행 시에는 로터를 정지시켜 날개로 사용하고 가스발생기에서 생성된 가스를 주 노즐로 분사하여 본래의 제트엔진으로 사용한다. ICV방법과 SIMULINK를 이용하여 천이 성능 해석을 수행하였다. 연료유량은 터빈 입구온도의 스텝과 과온 현상을 피하기 위해 램프 증가를 하였고 이에 따른 추력의 변화와 터빈 입구온도의 변화를 살펴보았다.

• 항공우주시스템공학회지
• /
• 제6권1호
• /
• pp.19-25
• /
• 2012

Nowadays, the demand of civil application of an UAV has been being increased all over the world. And many projects are going on to develop a new regulatory system for an UAV to access a national airspace. Especially, to fly UAV over the non-restricted airspace as a standard airworthiness standard, many authority funded research institutes and associations are studying regulatory environment. For the UAV to access civil airspace, the certification system of the aviation regulation have to allow this. FAA of US, CASA of Australia and European authorities are now issuing an experimental airworthiness certificate to a civil UAV. This is the first step of issuing a standard airworthiness certificate. And many people believe that civil UAV can fly over a NAS if some technical issues are resolved. In this study, I would like to present an international trends of a civil UAV regulation system, reliability trend of unmanned aerial system and would like to bring up a our regulatory environment and suggest an UAV regulatory policy.

• International Journal of Aeronautical and Space Sciences
• /
• 제11권3호
• /
• pp.167-174
• /
• 2010

The design, dynamics, and control allocation of tri-rotor unmanned aerial vehicles (UAVs) are introduced in this paper. A trirotor UAV has three rotor axes that are equidistant from its center of gravity. Two designs of tri-rotor UAV are introduced in this paper. The single tri-rotor UAV has a servo-motor that is installed on one of the three rotors, which enables rapid control of its motion and its various attitude changes-unlike a quad-rotor UAV that depends only on the angular velocities of four rotors for control. The other design is called 'coaxial tri-rotor UAV,' which has two rotors installed on each rotor axis. Since the tri-rotor type of UAV has the yawing problem induced from an unpaired rotor's reaction torque, it is necessary to derive accurate dynamic and design control logic for both single and coaxial tri-rotors. For that reason, a control strategy is proposed for each type of tri-rotor, and nonlinear simulations of the altitude, Euler angle, and angular velocity responses are conducted by using a classical proportional-integral-derivative controller. Simulation results show that the proposed control strategies are appropriate for the control of single and coaxial tri-rotor UAVs.

• 제어로봇시스템학회논문지
• /
• 제22권9호
• /
• pp.759-765
• /
• 2016

This paper presents the principle, dynamics modeling and control, hardware implementation, and flight test result of a hybrid-type unmanned aerial vehicle (UAV). The proposed UAV was designed to provide both hovering and fixed-wing type aerodynamic flight modes. The UAV's flight mode transition was achieved through the attitude transformation in pitch axis, which avoids a complex rotor tilt mechanism from a structural and control viewpoint. To achieve this, a different navigation coordinate was introduced that avoids the gimbal lock in pitch singularity point. Attitude and guidance control algorithms were developed for the flight control system. For flight test purposes, a quadrotor attached with a tailless fixed-wing structure was manufactured. An onboard flight control computer was designed to realize the navigation and control algorithms and the UAV's performance was verified through the outdoor flight tests.

• 한국추진공학회지
• /
• 제15권2호
• /
• pp.1-7
• /
• 2011

다양한 비행환경에서 장시간 체공하며 운용되는 UAV에서 추진시스템을 신뢰성 있게 운용하는 것은 매우 중요하다. 이런 UAV에 사용되는 터보프롭 엔진의 정확한 손상진단은 신뢰성과 이용률을 향상시킬 수 있다. 본 연구에서는 엔진 측정 파라미터들의 변화로부터 퍼지 이론을 적용하여 손상된 구성품을 식별한 후 훈련된 신경망 알고리즘을 식별된 손상 패턴에 적용하여 손상된 양을 정확히 진단할 수있는 방법을 제안하였다. 이렇게 제안된 진단 방법은 단일손상과 다중손상 모두 진단할 수 있다.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2010년도 제35회 추계학술대회논문집
• /
• pp.499-505
• /
• 2010

다양한 비행환경에서 장시간 체공하며 운용되는 UAV에서 추진시스템을 신뢰성 있게 운용하는 것은 매우 중요하다. 이런 UAV에 사용되는 터보프롭 엔진의 정확한 손상진단은 신뢰성과 이용률을 향상시킬 수 있다. 본 연구에서는 엔진 측정 파라미터들의 변화로부터 퍼지 이론을 적용하여 손상된 구성품을 식별한 후 훈련된 신경망 알고리즘을 식별된 손상 패턴에 적용하여 손상된 양을 정확히 진단할 수 있는 방법을 제안하였다. 이렇게 제안된 진단 방법은 단일손상과 다중손상 모두 진단할 수 있다.

• 한국항공우주학회지
• /
• 제40권7호
• /
• pp.582-589
• /
• 2012

본 논문은 무인 항공기에서 지상의 차량을 촬영하여 차종을 인식하기 위한 알고리즘의 개발에 대해 논하고 있다. NCC(Normalized Cross-Correlation) 방법을 이용하여 영상에서 목표물의 기하학적인 정보를 정합하도록 하였고, 실제 비행영상을 통해 획득한 템플릿 이미지와 위성 지도를 통해 획득한 템플릿 이미지를 이용하여 영상의 정합을 수행하였다. 실내 기반 실험을 통해 정합 가능성을 평가하였으며, 위성 지도를 이용한 모의실험을 통해 NCC 알고리즘을 이용하여 차량의 종류를 식별할 수 있음을 확인하였다. 마지막으로 실제 비행 실험을 통해 획득한 영상을 통해 동일한 차량을 전체 영상에서 정합하는 실험을 수행하였다. 비행 실험 결과 승용차의 위치가 정확하게 탐지되었으며, 정합 결과 0.6점이상의 유사도가 나타남을 확인할 수 있었다. 또한 유사한 색상을 지닌 트럭은 정합하지 않음으로서 이종 차량의 구분이 가능함을 확인하였다.

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