• 한국항공우주학회지
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• 제50권7호
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• pp.489-496
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• 2022

본 논문에서는 한국항공대학교에서 설계 및 개발한 태양광 무인기인 KAU-SPUAV의 시스템을 소개하고 비행시험을 통하여 성능을 검증하였다. 두 가지 버전의 태양광 무인기의 제원과 전장 구성 그리고 지상 관제 시스템을 소개하였다. 제시한 시스템으로 전파맵 구축, 제주도 해안선 일주 그리고 장기 체공 비행의 세 가지 임무 비행을 수행하였다. 각 임무는 태양광 무인기의 특성을 이용하는 비행으로서 주로 장시간 및 장거리 임무로 구성되었다. 본 연구를 통하여 태양광 무인기의 장기체공 능력을 이용해 다양한 임무에 사용될 수 있음을 보였다. 비행 시험 결과를 기반으로 시스템 추가 개선을 통하여 성능 향상을 도모할 수 있음을 확인하였다.

• 한국항공우주학회지
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• 제31권6호
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• pp.96-101
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• 2003

과학로켓3호(KSR-III) 비행시험시에 탑재용 원격측정장치는 로켓의 서브시스템들의 실시간 상태 및 각종 센서 자료를 획득하여 무선으로 전파 통신을 하고 지상에서 로켓을 추적하면서 비행중인 원격측정 데이터를 실시간으로 획득하고 복원하는 것은 로켓의 비행을 분석하는데 필수적이다. 또한 실시간으로 자료처리된 원격측정자료들은 네트워크를 통해 임무통제센터로 보내져 로켓의 비행 궤도를 도시하고 동시에 비행통제원이 로켓의 비행종단명령을 수행하기 위한 중요한 판단자료를 제공한다. 본 논문에서는 과학로켓3호 비행시험에 적합한 원격측정 수신과 관련된 운용기법 및 실시간 자료처리 시스템 개발에 관하여 기술하였으며 원격측정 수신결과를 분석하였다. 실제 비행시험시에 성공적으로 원격측정 수신 및 실시간 자료처리 임무를 완수하였다.

• 항공우주시스템공학회지
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• 제9권2호
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• pp.25-33
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• 2015

Global market of unmanned aircraft(UA) is rapidly expending based on the versatile and efficient utility of the UA. Domestically many industries, universities and research institutes are trying to do research and development of the UA in various angle of aspect. In spite of these effort, all the participants of research and development of the UA has been suffering the difficulty of acquiring the airspace around vicinity of Goheung airfield for the flight test of UA. Although the current procedure of execution of the flight test of UA is set after acquiring the airspace by applying the NOTAM(Notice To Air Man) to the Ministry of Land, Infrastructure and Transport(MLIT) at least 7 days before the flight test and commencing with the publication of the NOTAM by MLIT, if the flight test is carried out as planned, changing or reapplying the NOTAM expends mort time and makes difficulty often. Therefore it is needed that a restricted airspace for the flight test of UA is established and make all the executioner of flight test uses the exclusive airspace without limitation. This research proposes the restricted airspace with short term and long term establish requirement of airspace separately. The short term requirement has been established with the airspace of 10 nm radius and 8,000 ft altitude in which the requirements of flight test can be carried out more than 90% without needs of supplement of the additional airspace. The long term has been established within the airspace of 30 nm radius which is the maximum Radio Line Of Sight(RLOS) and 8,000 ft altitude with exclusion of current air way, airport control area, approaching corridor to the airport, existing restricted area(RA) and Military Operating Area(MOA) for the purpose of minimizing inconvenience of the other airspace user. Once establishing the exclusive airspace for the flight test of UA, research and development of industries, universities and research institutes will be more vigorous and contributes to the national economy.

• International Journal of Aerospace System Engineering
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• 제4권1호
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• pp.13-21
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• 2017

In this paper, we present some results on performance analysis for flap actuation system of aircraft. For this, by utilizing MATLAB/Simulink solution, which is widely used physical model-based design tool, we particularly construct the architecture of the analysis model consisting of the main three phases: 1)commanding and outer-controlling the flap angle through flight control computer; 2)generating hydraulic/mechanical power through control module and power drive unit; 3)transmitting torque and actuating the flap through torque tube and rotary geared actuators. For mimicking the motion of the actual flap, we apply each mechanical component, which is already being used in actual aircraft, to our performance analysis model so that it guarantees the congruency of the simulation results. That is, we reflect the actual specifications of flap hardware and software as parameters of the model. Finally, simulation results are presented to illustrate the model.

• International Journal of Control, Automation, and Systems
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• 제5권1호
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• pp.24-34
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• 2007

Closed-loop active twist control of integral helicopter rotor blades is investigated in this paper for reducing hub vibration induced in forward flight. A four-bladed fully articulated integral twist-actuated rotor system has been designed and tested successfully in wind tunnel in open-loop actuation. The integral twist deformation of the blades is generated using active fiber composite actuators embedded in the composite blade construction. An analytical framework is developed to examine integrally twisted helicopter blades and their aeroelastic behavior during different flight conditions. This aeroelastic model stems from a three-dimensional electroelastic beam formulation with geometrical-exactness, and is coupled with finite-state dynamic inflow aerodynamics. A system identification methodology that assumes a linear periodic system is adopted to estimate the harmonic transfer function of the rotor system. A vibration minimizing controller is designed based on this result, which implements a classical disturbance rejection algorithm with some modifications. Using the established analytical framework, the closed-loop controller is numerically simulated and the hub vibratory load reduction capability is demonstrated.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2006년도 제27회 추계학술대회논문집
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• pp.203-206
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• 2006

액체 추진로켓의 총역적을 극대화를 위한 추진제 잔류량 최소화를 목적으로 하는 추진제 소진 시스템에 대한 분석을 수행하였다. 추진제 잔류량 변화의 주요 인자는 비행중 추진제 혼합비와 추진제의 실제 탑재량이다. 특히 극저온 추진제를 이용할 경우에는 온도 변화에 따른 밀도 변화가 잔류량 변화에 큰 영향을 준다. 비행 중 산화제 및 연료의 수위를 측정하여 필요 시 엔진으로 공급되는 유량을 조절함으로서 산화제 및 연료가 동시에 소진되도록 하는 시스템을 이용하여 잔류량을 최소할 수 있다. 이러한 시스템을 도입하기 위해서는 액체 로켓엔진의 혼합비 제어 시스템이 동반되어야 한다.

• International Journal of Aeronautical and Space Sciences
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• 제17권1호
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• pp.54-63
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• 2016

A novel attitude tacking control method using Time Delay Control (TDC) scheme is developed to provide robust controllability of a rigid hexacopter in case of single or multiple rotor faults. When the TDC scheme is developed, the rotor faults such as the abrupt and/or incipient rotor faults are considered as model uncertainties. The kinematics, modeling of rigid dynamics of hexacopter, and design of stability and controllability augmentation system (SCAS) are addressed rigorously in this paper. In order to compare the developed control scheme to a conventional control method, a nonlinear numerical simulation has been performed and the attitude tracking performance has been compared between the two methods considering the single and multiple rotor faults cases. The developed control scheme shows superior stability and robust controllability of a hexacopter that is subjected to one or multiple rotor faults and external disturbance, i.e., wind shear, gust, and turbulence.

• 한국컴퓨터정보학회논문지
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• 제21권10호
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• pp.125-133
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• 2016

In this paper, we propose a real-time fault monitoring and dual system design of the countdown time-generating system, which is the main component of the mission control system. The countdown time-generating system produces a countdown signal that is distributed to mission control system devices. The stability of the countdown signal is essential for the main launch-related devices because they perform reserved functions based on the countdown time information received from the countdown time-generating system. Therefore, a reliable and fault-tolerant design is required for the countdown time-generating system. To ensure system reliability, component devices should be redundant and faults should be monitored in real time to manage the device changeover from Active mode to Standby mode upon fault detection. In addition, designing different methods for mode changeover based on fault classification is necessary for appropriate changeover. This study presents a real-time fault monitoring and changeover system, which is based on the dual system design of countdown time-generating devices, as well as experiment on real-time fault monitoring and changeover based on fault inputs.

• 제어로봇시스템학회논문지
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• 제14권8호
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• pp.745-751
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• 2008

This paper presents a framework for GPS/INS/Vision based navigation system of helicopters. GPS/INS coupled algorithm has weak points such as GPS blockage and jamming, while the helicopter is a speedy and high dynamical vehicle amenable to lose the GPS signal. In case of the vision sensor, it is not affected by signal jamming and also navigation error is not accumulated. So, we have implemented an GPS/INS/Vision aided navigation system providing the robust localization suitable for helicopters operating in various environments. The core algorithm is the vision based simultaneous localization and mapping (SLAM) technique. For the verification of the SLAM algorithm, we performed flight tests. From the tests, we confirm the developed system is robust enough under the GPS blockage. The system design, software algorithm, and flight test results are described.

• 한국정보전자통신기술학회논문지
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• 제15권6호
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• pp.457-462
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• 2022

최근 드론을 엔터테인먼트 도구로 이용하는 문화생활이 다양하게 만들어지고 있고, 이를 실현하기 위해 비행 금지 구역을 침범할 정도로 성능이 좋은 드론을 이용하는 사용자가 많아지고 있다. 만족도가 높은 엔터테인먼트 활동을 위한 드론은 체공 시간도 길어야 하고 장거리 비행도 가능해야 하는데, 이것이 종종 비행 금지구역을 침범하거나 또는 원하지 않는 비행 충돌 문제가 발생하여 큰 피해가 날 수 있다. 본 연구에서는 이러한 문제를 해결하기 위하여 GCS(Ground Control System)로 비행 금지구역을 설정하고, 임계속도 10km/h 이하로 비행할 경우 비행 금지구역으로부터 10m 떨어진 임계거리 안으로 들어오지 않게 하여 안전하게 드론을 조종하게 하고, 임계속도 이상으로 비행해서 임계거리 안으로 진입할 경우 드론이 GCS 제어에 의해 self-drop 하도록 하여 비행 금지구역 안으로 들가지 못하도록 하는 방법을 제안하였다. 제안한 방법으로 특정 실험 지역에서 총 44번의 반복실험을 한 결과 한두번 제한구역을 넘어간 경우를 제외하고는 드론이 안전하게 self-drop한 결과를 얻었으며 제안한 방법으로 드론을 제어할 경우 비행 금지구역으로 넘어가는 것을 막을 수 있는 적절한 방법임을 확인할 수 있었다.