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

• 한국항공우주학회지
• /
• 제35권4호
• /
• pp.308-315
• /
• 2007

연구는 경비행기인 창공-91의 인증 획득을 위한 비행시험의 일부로서 상승성능을 파악하기 위하여 수행되었다. 창공-91은 1993년에 대한민국의 건설교통부로부터 최초로 인증을 취득한 단발엔진을 장착한 일반유형의 5인승 항공기이다. 상승을 위한 비행시험 절차 및 자료는 형식증명을 획득하는데 사용되었다. 톱니형 상승 데이터로부터 양항곡선방법으로 데이터를 처리하여 창공-91의 최대상승률, 최대상승각 속도, 최대상승률 속도, 그리고 절대상승한도를 구하였다. 또한, 상승성능의 결과로부터 양항곡선식을 구함으로써 형상항력계수와 오스왈드 효율계수를 비행기 설계시의 값과 비교하였다.

• 농업과학연구
• /
• 제50권3호
• /
• pp.427-435
• /
• 2023

This study was conducted to evaluate the spraying performance according to the flight conditions of agricultural drones for the development of a variable control system. The analyzed flight conditions comprised six factors: spraying direction, flight speed, altitude, wind speed, wind direction, and rotor rotational speed. The ratio of the area sprayed on the water-sensitive paper was used as the coverage, and the distribution and amount of the coverage were evaluated. The coverage distribution based on the distance from the drone was used to evaluate a spray pattern, and the distribution was expressed as a Gaussian function approximation. In addition, the probability distribution based on coverage was expressed as the cumulative probability via Gamma function approximation to analyze the spraying efficiency in the target area. The results showed that the averaged coverage decreased significantly as the flight speed and wind speed increased, and the wind direction changed the spray pattern without a coverage decrease. This study contributes to the development of a control technique for the precision control system of agricultural drones.

• 한국항공운항학회지
• /
• 제23권2호
• /
• pp.15-20
• /
• 2015

This paper introduces a new airspace design method for continuous climb operation (CCO). The optimization problem is formulated as Mixed-Integer Linear Program (MILP) to maximize the upper limits of altitude on the waypoints to facilitate continuous climb for aircraft. In the proposed method, the interactions with other flight procedures are considered as well as various aircraft flight performances. The proposed method is applied to one of the departure procedures of Incheon International Airport (ICN) to demonstrate its performances.

• International Journal of Aeronautical and Space Sciences
• /
• 제9권1호
• /
• pp.31-41
• /
• 2008

This paper deals with the energy saving problem of the follower aircraft in the loose leader-follower formation geometry in which the lateral separation between formation members is more than a wingspan of the leader aircraft. This formation geometry offers no drag benefit, but has a strategic advantage. In the case of loose formation flight, the follower aircraft usually consumes more energy than the leader aircraft because the follower aircraft should use more thrust to maintain given formation geometry, especially during the turning phase from the outside of the leader"s flight path or join-up phase. A formation control scheme based on the energy maneuverability is proposed in this paper. To design the proposed control law, the velocity command is designed using feedback linearization for the horizontal formation geometry and then coverts it to the altitude command using the energy equation. Numerical simulation is performed to verify the effectiveness of the proposed controller.

• International Journal of Aerospace System Engineering
• /
• 제4권2호
• /
• pp.5-9
• /
• 2017

In a pressurized fuel supply system of aircraft, a flow passage opening device is required to keep fuel continuously transferred from one tank to the other. The device utilizes balancing weights in order to follow up an acceleration at special conditions such as negative g. It is very difficult to test the device in a real high-speed and high-altitude test since severe test conditions and expensive supports are needed. Therefore, this paper deals with performance analysis of a flow passage opening device through low speed aircraft captive flight tests (CFT) including roll and negative-g maneuvers. It is shown that balancing weights in the device can open the passage in accordance with fuel position.

• 항공우주시스템공학회지
• /
• 제3권4호
• /
• pp.35-40
• /
• 2009

The first purpose of this study is to develop a GCS(Ground Control System) by using RF(Radio Frequency) wireless communication equipments for UAV(Unmanned Aerial Vehicle). The second goal is to develop an antenna tracking system operating automatically. UAV receives flight data from a RF wireless system. So the role of antenna tracking system is very important to keep good communication state between UAV and GCS. GCS can check flight data and display a aviation state of UAV in real-time. The flight data displayed in real-time by GCS include the latitude, longitude, altitude, speed and so on. Experiments that measure a communication range and reliability are needed to develop a RF wireless communication system.

• 한국항공우주학회지
• /
• 제33권6호
• /
• pp.51-56
• /
• 2005

본 논문에서는 GPS/INS/기압고도계를 결합한 고도 항법 알고리즘과 이를 구현한 실험 결과를 소개한다. 실험 결과의 분석을 통해 제안된 알고리즘이 무인항공기 비행제어 시스템에 적합한, 연속적이며 고도 변화에 민감한 고도 정보를 제공할 수 있음을 확인한다. 그리고 기존의 INS/기압고도계를 결합한 고도 항법 시스템의 경우 2차, 3차 구조 모두 본질적으로 상보 필터(complementary filter)의 형태를 가지기 때문에 기압고도계의 오차를 보상할 수 없는데, 제안된 알고리즘은 이러한 단점을 개선하는 구조로 구성되어 있음을 보인다.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2010년도 제35회 추계학술대회논문집
• /
• pp.825-828
• /
• 2010

항공용 가스터빈 엔진은 운용 범위가 넓으며 고고도에서 운용되므로 극한 환경조건에서의 운용을 요구하며 높은 신뢰성을 요구한다. 따라서 본 연구에서는 혹독한 환경에서 높은 수준의 신뢰성 있는 연소기 개발을 위한 연소기 리그시험 및 엔진 단위의 운용 안정성 평가를 수행, 최적화하였으며, 엔진개발 단계에서 수립된 시동로직을 반영하여 고고도 운전영영에서의 시동 및 운용 안정성을 검증하였다. 리그 및 엔진시험 결과, air swirler가 장착된 인젝터를 적용할 경우, 20kft Hot day 및 $-40^{\circ}C$에서 정상적인 운용 및 시동이 이루어졌다.

• 한국환경복원기술학회지
• /
• 제18권6호
• /
• pp.151-165
• /
• 2015

This study surveys and analyzes the ecology of Gangseo area to be developed near Nakdonggang River and West Nakdonggang River in Busan - before its development. With the result of the surveys as its basis, the study also finds ways to conserve the area's bird habitats in response to the planned development. According to the site surveys over four seasons, West Nakdonggang River which is near the targeted development area is a wintering ground for migratory birds. Some representative bird types in this area are ducks, geese, and other water birds. There are even six legally protected species. The average altitude of their flight is calculated to be $92.4{\pm}18.8m$ and the main purpose for the migration is determined to be for food. According to evalution of the conservation value of the area, Nakdonggang River and West Nakdonggang River turns out to have the highest conservation value. Other areas are developable as long as it was environmentally friendly. Therefore, this study suggests incorporation of ecological parks and biotopes within the targeted development area along with the proposal for spaces in the surroundings where the wintering birds can rest and feed. Especially for the wintering birds that rest at Nakdonggang River and West Nakdonggang River, their flight direction and pattern was examined to determine that their resting ground should be located 50~100m off of the river bank. Furthermore, this study proposes ways to maximize bird habitat by building ecological corridors between the agricultural channel and other small streams in the targeted development area and the habitats in the surroundings. Lastly, the study suggests the construction of low buildings, at most 20m in height, near Nakdonggang River and West Nakdonggang River considering the birds' flight altitude and direction.