• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.7
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• pp.531-538
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• 2017

A flush air data sensing system, which can predict flight speed, angle of attack, and angle of sideslip of the aircraft is designed and manufactured for a small UAV. Two kinds of flush pressure ports, four ports and five ports, are tapped at the same section of fuselage nose-cone. Calibration pressure data at flush ports are obtained through computations for the total aircraft by using Fluent code. Angle of attack, angle of sideslip, total pressure, and static pressure are represented with 4th-order polynomial function and calibration coefficient matrix is obtained using least square method with calibration pressure data. Flight test showed that flight speed, angle of attack, and sideslip angle predicted by four flush ports and five flush ports compared well with those by five-hole probe installed for data comparison. Especially four flush ports revealed nearly same results as those by five flush ports.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.11
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• pp.821-829
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• 2019

Because rotorcraft is unstable, it needs a stability system such as flybar. Recently, sensor technology has been developed, it uses a stability augmentation system to improve stability instead of flybar. To use of these rotorcraft which include stability augmentations system for unmanned system, flight control computer, include stability augmentations system function, must be required. In this paper, a reverse-engineering method of estimating Algorithm of Commercial Stability Augmentation System is proposed, the result is applied in the flight computer to make an unmanned rotorcraft system. Finally using a validated algorithm, it is possible to establish a system of unmanned automatic rotorcraft system.

• KIPS Transactions on Computer and Communication Systems
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• v.8 no.12
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• pp.277-286
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• 2019

The Unmanned Aerial Vehicle (UAV) is one of the most precious inventions of Internet of things (IOT). UAV faces the necessity to charge battery or replace battery from the charging stations during or between services. We propose scheduling algorithms for drone power charging (SADPC). The basic idea of algorithm is considering both a deadline (for increasing deadline miss ratio) and a charging time (for decreasing waiting time) to decide priority on charging station among drones. Our simulation results show that our power charging algorithm for drones are efficient in terms of the deadline miss ratio as well as the waiting time in general in compare to other conventional algorithms (EDF or SJF). Also, we can choose proper algorithms for battery charge scheduling and charge ready battery allocation according to system parameters and user requirements based on our simulation.

• Proceedings of the Korean Society of Computer Information Conference
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• 2012.01a
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• pp.49-50
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• 2012

본 논문에서는 다수의 소형 무인 항공기(UAV) 그룹이 이동 중 장애물을 만났을 때 장애물과의 충돌을 방지하는 효율적인 장애물 회피 정책을 제안한다. 이 정책은 무선 에드혹(moblie ad hoc) 네트워크를 기반으로 단순히 UAV 간의 충돌 회피 뿐만이 아니라 UAV 그룹이 이동하는 도중 장애물을 발견 하였을 경우 장애물을 효율적으로 회피하는 방법과 연결성이 손실되는 경우에 대처하는 방안도 고려하였다. 제안하는 정책은 UAV가 장애물을 포착 하였을 때 현재 이동 속도를 유지한 채 장애물을 기준으로 UAV 그룹을 2개의 그룹으로 분리하여 장애물을 회피 한 후 일정한 지점에서 모여 다시 각 UAV간의 연결성을 유지한 채 목표물을 향해 이동하는 정책을 제안한다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.5
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• pp.445-452
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• 2017

The wing leading edge skin in this research is an essential structural factor for improving wings' aeromechanical functions, protecting the interior elements of the wings from external damage including birds, and navigating planes safely. The study compared and reviewed models manufactured for optimal light-weight wings of composite UAVs. It compared and investigated displacement forms of torsion loads through finite element analysis using MSC. Patran/Nastran. By confirming the improvement of light-weighting performance according to lamination type, thickness change and shape through torsion strength tests of each model, the research suggested the optimal light-weight wing leading edge skin for small composite UAVs.

• Journal of Advanced Navigation Technology
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• v.8 no.2
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• pp.112-119
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• 2004

This paper proposes an attitude determination GPS/INS integrated system scheme for a UAV and presents experimental flight test results. The proposed system is designed as a part of an autopilot system and comprises a GPS attitude determination receiver, an off-the-shelf inertial measurement unit (IMU), and a navigation computer unit (NCU). UAV requires accurate attitude information for stable automatic flight control. The proposed system can provide accurate attitude information for the flight control computer (FCC) so that stable automatic flight control can be achieved. In order to verify the performance of the proposed scheme, an integrated navigation system has been developed. In order to evaluate the developed navigation system, the flight test has been performed. In the flight test, the developed system was shown to provide the position, the velocity and the attitude satisfactorily enough for stable flight control. The accuracy of the attitude information of the developed system was confirmed by comparing attitude of vertical gyro.

• Economic and Environmental Geology
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• v.48 no.3
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• pp.205-212
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• 2015

We have verified applicability of UAV(Unmanned Aerial Vehicle) photogrammetry to a mining engineering. The test mine is a smectite mine located at Gyeongju city in Gyeongnam province, Koera. 448 photos over area of $600m{\times}380m$ were taken with overlapped manner using Cannon Mark VI equipped to multicopter DJI S1000, which were processed with AgiSoft Photoscan software to generate orthophoto and DEM model of the study area. photogrammetry data with 10 cm resolution were generated using 6 ground control positions, which were exported to the 3D geological modeling software to make a topographic surface object. Monitoring of amount of ore production and landsliding could be done with less than 1 hours photographing as well as low cost. A direct link between UAV photogrammetry and 3D geological modeling technology might increase productivity of a mine due to appling the topographical surface change immediately according to the mining operation.

• Journal of Aerospace System Engineering
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• v.14 no.spc
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• pp.39-48
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• 2020

This paper deals with the process of estimating the environmental noise generated from the actual flying aircraft using the noise measurement results obtained through the wind tunnel test and verifying it through flight tests. In order to evaluate the environmental noise of an aircraft, noise tests and evaluations are generally conducted according to the procedures prescribed by the International Civil Aviation Organization (ICAO). In this paper, we introduced environmental noise evaluation method that can be applied to composite both fixed-wing aircraft and multi-copter, and introduced the evaluation method by experiment. This paper introduces the process of simulating the noise test results measured in the wind tunnel test using real flight test results. In addition, in consideration of flight operating conditions and noise measurement methods proposed by the ICAO, the effective perceived noise level (EPNL) was predicted by performing both the wind tunnel test and the aircraft flight test.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.2
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• pp.22-31
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• 2005

A design study was conducted for a new concept aircraft(Canard Rotor/Wing: CRW) that has the capability of dual mode flight, a rotorcraft and a fixed wing mode. The CRW can show a vertical take off/landing and a high speed/efficiency cruise performance simultaneously. It is not surprising to develop a new sizing code for this class of aircraft because conventional sizing codes developed solely for either the rotary wing or the fixed wing aircraft are not adequate to design a dual mode aircraft operated both by the rotary wing through tip jet effux and the fixed wing lift. Thus, a new design code was developed based on the conventional sizing code by adding some features including rotor performance, duct flow, and engine flow analysis, hence could eventually predict the performance of reaction driven rotor, the flight performance and the flight characteristics. The various design parameters were investigated to find their influences on the flight performance then, a small UAV(Unmanned Aircraft Vehicle) of 1500 lbs class was optimally designed to have minimum weight using the developed sizing code.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.3
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• pp.226-232
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• 2013

A compact hydrogen generation device of fuel cell system using chemical hydride storage technique was designed to fit the propulsion device requirement of a small unmanned aerial vehicle(SUAV). For high efficient, compact, and lightweight hydrogen generation control device, the Co-B catalyst hydrogen conversion rate by $NaBH_4$ aqueous solution flux is measured so that the proper amount of Co-B catalyst for maximum hydrogen generation of 100W stack was proposed. A compact hydrogen generation device is controlled by pump's on/off using its own internal pressure and consumes fuel in high efficiency through a dead-end type fuel cell. The fuel cell system has stable operation for a planed flight profile. The system operates up to maximum 7 hours and at least 4 hours for tough flight profiles.