• Tunnel and Underground Space
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• v.26 no.1
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• pp.24-31
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• 2016

Recently, many studies have been conducted to use fixed-wing and rotary-wing unmanned aerial vehicles (UAVs, Drones) for topographic surveying in open-pit mines. Because the fixed-wing and rotary-wing UAVs have different characteristics such as flight height, speed, time and performance of mounted cameras, their results of topographic surveying at a same site need to be compared. This study selected a construction site in Yangsan-si, Gyeongsangnam-do, Korea as a study area and compared the topographic surveying results from a fixed-wing UAV (SenseFly eBee) and a popular rotary-wing UAV (DJI Phantom2 Vision+). As results of data processing for aerial photos taken from eBee and Phantom2 Vision+, orthomosaic images and digital surface models with about 4 cm grid spacing could be generated. Comparisons of the X, Y, Z-coordinates of 7 ground control points measured by differential global positioning system and those determined by eBee and Phantom2 Vision+ revealed that the root mean squared errors of X, Y, Z-coordinates were around 10 cm, respectively.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.2
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• pp.105-114
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• 2008

In this study, the sizing and performance analysis program is developed for the canard rotor wing(CRW) aircraft which operates in dual modes (fixed wing mode and rotary wing mode). The developed program is verified for both fixed wing and rotary wing modes using the existing aircraft data and the design optimization formulation is made to perform the reconnaissance mission. For the canard rotor wing aircraft optimization , multi-objective function is constructed to consider both the fixed wing mode and rotary wing mode the weighting factor. For six design cases with different weighting factors and different design constraints, the optimization is performed and improved rotor design results are derived.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.9
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• pp.16-26
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• 2005

The aerodynamic design of a proprotor for the Smart UAV adopting tiltrotor aircraft concept is conducted in this study. Since proprotor of tiltrotor aircraft is operated at both rotary and fixed wing mode with single configuration rotor, the proprotor has to be designed to meet performance requirements for both flight modes. The aerodynamic design of proprotor is accomplished by combining three sources of data - the proprotor performance data, the aerodynamic data of vehicle, and the performance data of engine. The performance analysis code for proprotor is based on the combined momentum and blade element theory and validated by comparison with the TRAM data. In order to design configuration for a proprotor satisfying requirements for both rotary and fixed wing mode, various kind of performance maps are constructed for many performance and configuration parameters. From the analysis the twist angle of 38 degrees and the solidity of 0.118 are decided to be the optimal geometric parameters for both operating conditions.

• Aerospace Engineering and Technology
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• v.5 no.2
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• pp.240-247
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• 2006

Tilt rotor aircraft is a multi-configuration airplane which has three independent flight modes; helicopter, conversion, and aiplane. The control surface mixer resign is reqctired to generate and distribute efficient control forces and moments in each flight mode. In the conversion mode, the thrust vector is changed from helicopter mode to airplane, therefore the thrust vector makes undesired forces and moments which affect on pitch, roll and yaw dynamics. This paper describes the design results of control surface mixer design which minimize the undesired forces and moments due to nacelles tilting angle change for 4O% scaled model.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.12
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• pp.857-866
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• 2022

Fixed-wing UAVs have long endurance and range capabilities compared to other aerial platforms. These advantages led fixed-wing UAVs to become a popular platform for reconnaissance missions in the military. In this research, we modeled fixed-wing UAVs, including the landing gear model and developed a guidance and control system for flight control computers to construct a HILS environment. We also developed an autopilot system that includes automated take-off, cruise, and landing control for UAVs. We also retrived the Aerodynamic coefficients an UAV using Datcom and AVL software and used them for 6 degrees of freedom modeling. The Flight control computer calculates guidance commands using the Carrot chasing guidance law after distinguishing the condition of the UAV based on 16 pre-defined flight modes and calculates control inputs using Nonlinear Dynamic Inversion (NDI) control scheme. We used RTNngine to integrate the Simulink model and flight control computer for HILS environment formulation.

• Journal of Aerospace System Engineering
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• v.18 no.4
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• pp.18-26
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• 2024

This paper describes the results of a study on Generic Quad Tilt Rotor UAM aircraft, focusing on nonlinear mathematical modeling and the development of real-time simulation software. In this research, we designed a configuration for a Generic Quad Tilt Rotor eVTOL UAM aircraft based on NASA's UAM mission requirements. We modeled the aerodynamics using a database, the prop-rotor dynamics with a thrust database, and included a ground reaction and atmospheric model in the flight model. We defined the control concept for various modes(helicopter mode, transition mode, and airplane mode), derived tilt angle corridors, and formulated flight control requirements. The resultant real-time flight simulation software not only performs trim analysis for Tilt Rotor UAM aircraft but also predicts handling qualities, optimizes tilt angle scheduling based on dynamic characteristics, designs and validates flight control laws for helicopter, transition, and airplane modes, and facilitates flight training through simulator integration.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.12
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• pp.1217-1224
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• 2009

A simple and effective guidance and control scheme that enables autonomous three-dimensional path-following for a fixed wing aircraft is presented. The method utilizes the nonlinear path-following guidance law for the outer loop that creates steering acceleration command based on the desired flight path and the current position and velocity of the vehicle. The scheme considers the gravity in the guidance level, where it is subtracted from the acceleration command to form the specific force acceleration command which the aircraft is better suited to follow than the total acceleration command in the inner-loop. A roll attitude control scheme is also presented that enables inverted flight or sideslip maneuvers such as slow roll and knife-edge. A series of aerobatic maneuvers are demonstrated through simulations to show the potential of the proposed scheme.

• Journal of the Korea Convergence Society
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• v.8 no.4
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• pp.183-188
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• 2017

As the price of small UAVs is getting cheaper and its controllability is getting greatly increased, many aerial applications using both fixed-wing and hoverable UAVs have appeared in recent years. In this paper, a new aerial advertising method is proposed using four hoverable UAVs. Using the UAV swarm control method, four UAVs are maneuvered to carry a $7.07{\times}7.07m^2$ square banner along collision-free and predefined waypoints for aerial advertising. According to simulation results, it takes about 270 s for UAVs to perform aerial advertising in $669{\times}669m^2$ size area and the minimum distance among UAVs turns out to be 0.45 m which proves there is no any collision. Due to abrupt direction changes of UAVs along the predefined waypoints, UAVs cannot always maintain exact square formation and it results the maximum and minimum side lengths of square formation to be 10.35 m and 1.96 m, respectively. Also, the maximum and minimum diagonal lengths of square formation turn out to be 14.75 m and 2.78 m, respectively.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.3
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• pp.408-415
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• 2019

Basically the dynamics of the fixed-wing aircraft is based on the airspeed which is relative to the wind, but when it comes to the track guidance and control, ground speed is the factor to be considered. Especially in the case of low-speed fixed-wing unmanned aerial vehicles the difference between the airspeed and the ground speed is significant depending on wind conditions, so that the heading control and the course control have to be designed separately. This paper represents the course control method using the pre-designed heading control gains which meet the desired characteristics. Also, waypoint guidance and control algorithms are suggested applying this control method. Finally the robustness of the proposed method is confirmed by 6-DoF nonlinear simulation.

• Aerospace Industry
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• s.108
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• pp.66-67
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• 2010

수직이착륙, 영어로는 VTOL(Vertical Take-Off and Landing)이라 불리는 기술은 공기역학을 거부한 첨단 항공우주기술이다. 일반적으로 고정익 항공기는 날개에서 발생하는 양력으로 하늘을 날지만 VTOL 항공기는 순수한 엔진 추력만으로 수직으로 이착륙하거나 단거리에서 이륙할 수 있다. 다만 높은 기술적 완성도를 요구하는 만큼 현재까지 실전 배치된 군용기 중 이 기술이 적용된 군용기는 해리어(Harrier)와 V-22 오스프리(Osprey), Yak-38 정도가 고작이다. 수직이착륙 기술에 대해 소개한다.