• Journal of Institute of Control, Robotics and Systems
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• v.18 no.9
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• pp.878-886
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• 2012

This paper investigates the implementation and flight test of realtime vision guided autopilot system based on virtual instrumentation platform. A graphical design process via virtual instrumentation platform is fully used for the image processing, communication between systems, vehicle dynamics control, and vision coupled guidance algorithms. A significatnt ojective of the algorithm is to achieve an environment robust autopilot despite wind and an irregular image acquisition condition. For a robust vision guided path tracking and hovering performance, the flight path guidance logic is combined in a multi conditional basis with the position estimation algorithm coupled with the vehicle attitude dynamics. An onboard flight test equipped with the developed realtime vision guided autopilot system is done using the rotary UAV system with full attitude control capability. Outdoor flight test demonstrated that the designed vision guided autopilot system succeeded in UAV's hovering on top of ground target within about several meters under geenral windy environment.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.3
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• pp.71-77
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• 2005

An unmanned aerial vehicle (UAV) is generally flied via a pre-planned flight path or real-time commands by an operator. To succeed in an assigned mission, analysis such as the line-of-sight analysis for communication between UAV and a ground data terminal should be performed. In this paper, various analysis algorithms which are performed by a ground control station in pre-flight and in-flight phases, are proposed for the safe flight of UAV. Note that the proposed algorithms can be applied to most UAV systems.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.12
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• pp.1204-1208
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• 2014

As required performance of UAV (Unmanned Aerial Vehicle) becomes more complex and complicated, required positioning accuracy is becoming more and more higher. GPS is a reliable world wide positioning providing system. Therefore, UAV generally acquires position information from GPS. But when GPS is not available such as too weak signal or too less GPS satellites environments, UAV needs alternative positioning system such as network positioning system. RSSI (Received Signal Strength Indicator) based positioning, which is one method of network positioning technologies, determines its position using RSSI measurements containing distance information from AP (Access Point)s. In that method, a selected AP's configuration has strong and tight relationship with its positioning errors. In this paper, for, we additionally account AP's configuration information by adopting DOP (Dilution of Precision) into AP selection procedures and provide more accurate RSSI based positioning results.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.11
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• pp.1112-1117
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• 2014

Unmanned aerial vehicles (UAVs) are a popular research topic because of a great ripple effect in the future. However, current UAV technologies cannot be applied to manual aerial vehicles without any modification. As an alternative to current UAV technology, humanoid robots are adopted as pilots. If a humanoid robot controls an aerial vehicle autonomously, not only could manual aerial vehicles be utilized as UAVs, but the humanoid robot would also be put into an environment created for humans and conduct some missions suitable for humans. Humanoid robots are also able to handle tools and equipment designed for humans. In order to prove that a humanoid robot can pilot an airplane, an experiment is performed and the results of this experiment are shown in this paper.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.275-275
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• 2019

기후변화에 따른 집중호우의 발생빈도와 강도가 증가하면서 대규모 홍수로 인한 인명 및 재산피해가 발생하고 있다. 그에 따라 홍수 상황을 신속하게 확보하고 홍수피해를 빠르게 예측하는 모니터링 기술이 필요하다. 최근 공간정보 분야에서 무인항공기 (UAV: Unmanned aerial vehicles)를 이용한 3차원 지형자료 확보 연구가 활발하게 이용되고 있다. 무인항공기는 지형자료 구축 뿐 만 아니라 홍수 시 신속한 홍수 모니터링이 가능하기 때문에, 본 연구에서는 무인항공기를 이용하여 홍수 전 지형자료 구축을 비롯하여, 홍수 시 모니터링, 홍수 후 지형자료 구축에 이르기까지 UAV를 이용한 홍수 모니터링 기술을 소개한다. 연구대상지는 금강 합류 직전 논산천 하류 1 km 지점으로, UAV를 이용한 지형자료를 구축하기 이전에 좌표 매칭을 위한 GCP (Ground Control Point ) 측량을 실시하고, UAV 비행계획을 수립하고 촬영한다. 촬영된 영상을 GCP좌표와 소프트웨어 (Pix4D)를 이용하여 정사영상과 DSM(Digital Surface Model)자료를 구축한다. 홍수시 UAV를 이용한 촬영을 통하여 동영상은 수재해 플랫폼에 송신하고, 이미지 영상은 홍수 전 영상처리와 동일한 방법을 이용하여 지형 자료를 구축하여, 홍수시 침수심이나 지형변화를 분석한다.

• ETRI Journal
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• v.45 no.5
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• pp.874-886
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• 2023

A joint resource-optimization scheme is investigated for nonorthogonal multiple access (NOMA)-enhanced scalable video coding (SVC) multicast in unmanned aerial vehicle (UAV)-assisted radio-access networks (RANs). This scheme allows a ground base station and UAVs to simultaneously multicast successive video layers in SVC with successive interference cancellation in NOMA. A video quality-maximization problem is formulated as a mixed-integer nonlinear programming problem to determine the UAV deployment and association, RAN spectrum allocation for multicast groups, and UAV transmit power. The optimization problem is decoupled into the UAV deployment-association, spectrum-partition, and UAV transmit-power-control subproblems. A heuristic strategy is designed to determine the UAV deployment and association patterns. An upgraded knapsack algorithm is developed to solve spectrum partition, followed by fast UAV power fine-tuning to further boost the performance. The simulation results confirm that the proposed scheme improves the average peak signal-to-noise ratio, aggregate videoreception rate, and spectrum utilization over various baselines.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.3
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• pp.59-65
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• 2009

Recently, UAV(unmanned aerial vehicle) has evolved into various figure and become miniaturized. On using existing design method, it is hard to make modelling and standardizing design of flight control system of the figure including cylinder like pipe. These problems are caused by uncorrect express of nonlinearity in controller design. Therefore, it is developed through step of correct modelling and simulation on real time sing high efficiency computer in aircraft development of various figure. This is reducing period and expense of aircraft development. For the shake of solving these problems, in-design method has been devised by H.M. Wang. In this paper, an object of control is cylindrical UAV instead of the general figure of aircraft. It was analyzed flight condition, specification about level flight of the UAV and was presented algorithm to find control value.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.8
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• pp.523-530
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• 2022

Since the Multi-UAV system for various missions is more complex than a single UAV, an efficient formation control method is required. In wide-area search mission, there is a need for a distributed control for flexible formation that has a low burden of communication and computation and enables autonomous formation between UAVs. This paper proposes a flexible formation operation method that considers the swarm formation, the bank alignment formation, and the formation movement to expand the scan area and improve search performance. The algorithm has a vibration characteristic of the second-order system for a relative distance and can design an algorithm through parameter tuning. In addition, we converted control commands to suit conventional UAV systems and demonstrated the performance of algorithms for a formation and movement of a formation through simulation.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.7
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• pp.622-628
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• 2016

The prosperity of IT technologies and the removal of restrictions regarding Unmanned Aerial Vehicles (UAVs), also known as drones, have driven growth in their popularity. However, without a proper solution to the problem of accident avoidance for UAVs, this popularity increases the potential for collisions between UAVs and between UAV and terrain features. These collisions can occur because UAVs to date have flown using radio control or image recognition based autonomous navigation. Therefore, we propose efficient UAV routing schemes to tackle the collision problem using vehicular communication systems. Performance evaluation by computer simulation shows that the proposed methods effectively reduce the collision probability and improve the routing efficiency of the UAV. Furthermore, the proposed algorithms are compatible and can be directly applied with small overhead to the commercial vehicular communication system implementation.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.85.4-85
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• 2002

$\textbullet$ Flying Robot is a kind of UAV as an autonomous hovering platform. $\textbullet$ Control system is high complex, and non-linear Multiple-Input, Multiple-Output (MIMO) system. $\textbullet$ Eexperiment-device capable of measuring roll, yaw and pitch angle with PID controller by PC. $\textbullet$ This paper proves results of simulation through velocity control in condition.