• 항공우주산업기술동향
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• 제6권2호
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• pp.143-153
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• 2008

본 논문에서는 자율비행(Autonomous Flight)의 연구동향 및 향후 발전방향에 대하여 기술하였다. 자율비행은 항공기의 예기치 않은 임의상황 발생에 대해서도 항공기가 스스로 인지하고, 판단 한 후 대처하는 것을 의미한다. 현재의 자율비행기술은 무인기를 위주로 개발되고 있으나, 차세대 항공교통관제 시스템 도입과 무인기의 활용성 증대 요구에 따라 자율비행기능이 항공교통관제시스템과 결합되어야 한다. 그러므로 현 항공교통관제 시스템의 주요 개요와 향후 변경될 차세대 항공교통관제 시스템의 주요 사항들을 살펴보았고, 자율비행기술 개발 현황을 기술하였으며 향후 발전방향을 전망하였다.

• 한국항행학회논문지
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• 제16권1호
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• pp.122-130
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• 2012

항공기 분리보증은 자유비행의 핵심요구사항이다. 본 논문에서는 위임권한 확대, 공역 효율성 문제 등 자유비행의 실증적 문제해결을 위해 자율형 운항 알고리즘을 제안하고, 제안된 알고리즘과 포텐셜 필드 알고리즘을 모델링하여 두 가지 조건의 시나리오 상황에서 항공기 성능 데이터를 활용, 알고리즘 성능 및 충돌해결과 운항 자율성 효과 등을 측정하였다. 실험결과 자유비행 공역 하에서 자율형 운항 알고리즘이 포텐셜 필드 알고리즘보다 알고리즘 성능, 충돌해결, 운항 자율성 효과 측면에서 우수하였다.

• 로봇학회논문지
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• 제16권3호
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• pp.245-249
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• 2021

In this paper, we present novel simulation contents for drone racing and autonomous flight of drone. With Depth camera and SLAM, we conducted mapping 3 dimensional environment through RTAB-map. The 3 dimensional map is represented by point cloud data. After that we recovered this data in Unreal Engine. This recovered raw data reflects real data that includes noise and outlier. Also we built drone racing contents like gate and obstacles for evaluating drone flight in Unreal Engine. Then we implemented both HITL and SITL by using AirSim which offers flight controller and ROS api. Finally we show autonomous flight of drone with ROS and AirSim. Drone can fly in real place and sensor property so drone experiences real flight even in the simulation world. Our simulation framework increases practicality than other common simulation that ignore real environment and sensor.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권2호
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• pp.595-609
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• 2020

In this study, we propose a decentralized mathematical model for predictive control of a system of multi-autonomous unmanned aerial vehicles (UAVs), also known as drones. Being decentralized and autonomous implies that all members make their own decisions and fly depending on the dynamic information received from other unmanned aircraft in the area. We consider a variety of realistic characteristics, including time delay and communication locality. For this flocking flight, we do not possess control for central data processing or control over each UAV, as each UAV runs its collision avoidance algorithm by itself. The main contribution of this work is a mathematical model for stable group flight even in adverse weather conditions (e.g., heavy wind, rain, etc.) by adding Gaussian noise. Two of our proposed variance control algorithms are presented in this work. One is based on a simple biological imitation from statistical physical modeling, which mimics animal group behavior; the other is an algorithm for cooperatively tracking an object, which aligns the velocities of neighboring agents corresponding to each other. We demonstrate the stability of the control algorithm and its applicability in autonomous multi-drone systems using numerical simulations.

• 로봇학회논문지
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• 제6권2호
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• pp.97-107
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• 2011

This paper describes efficient flight control algorithms for building a reconfigurable ad-hoc wireless sensor networks between nodes on the ground and airborne nodes mounted on autonomous vehicles to increase the operational range of an aerial robot or the communication connectivity. Two autonomous flight control algorithms based on adaptive gradient climbing approach are developed to steer the aerial vehicles to reach optimal locations for the maximum communication throughputs in the airborne sensor networks. The first autonomous vehicle control algorithm is presented for seeking the source of a scalar signal by directly using the extremum-seeking based forward surge control approach with no position information of the aerial vehicle. The second flight control algorithm is developed with the angular rate command by integrating an adaptive gradient climbing technique which uses an on-line gradient estimator to identify the derivative of a performance cost function. They incorporate the network performance into the feedback path to mitigate interference and noise. A communication propagation model is used to predict the link quality of the communication connectivity between distributed nodes. Simulation study is conducted to evaluate the effectiveness of the proposed reconfigurable airborne wireless networking control algorithms.

• 대한임베디드공학회논문지
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• 제11권3호
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• pp.193-200
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• 2016

This paper introduces an algorithm to middle-low price drone's autonomous navigation flight system using computer vision and GPS. Existing drone operative system mainly contains using methods such as, by inputting course of the path to the installed software of the particular drone in advance of the flight or following the signal that is transmitted from the controller. However, this paper introduces new algorithm that allows autonomous navigation flight system to locate specific place, specific shape of the place and specific space in an area that the user wishes to discover. Technology developed for military industry purpose was implemented on a lower-quality hobby drones without changing its hardware, and used this paper's algorithm to maximize the performance. Camera mounted on middle-low price drone will process the image which meets user's needs will look through and search for specific area of interest when the user inputs certain image of places it wishes to find. By using this algorithm, middle-low price drone's autonomous navigation flight system expect to be apply to a variety of industries.

• 한국기계가공학회지
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• 제17권2호
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• pp.109-117
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• 2018

The experimental results are presented of an autonomous flight algorithm of a foldable quadcopter with airdrop launching functions. A foldable wing structure enabled the quadcopter to be inserted into a rocket container with limited space. The foldable quadcopter was then separated from the rocket in the air. The flight pattern was tracked using a global positioning system (GPS) with various sensors, including an inertial measurement unit (IMU) module until a designated target position was reached. Extensive field tests were conducted through an international rocket competition, ARLISS 2017, which was held in Black Rock Desert, Nevada, USA. The flight trajectory record of the experiments is stored in electrically erasable programmable read-only memory (EEPROM) embedded in the main control unit. The flight record confirmed that the quadcopter successfully separated from the rocket, executed flight toward the target for a certain length of time, and stably landed on the ground.

• 전자통신동향분석
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• 제38권3호
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• pp.11-19
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• 2023

Drones, which were early operated by remote control, have evolved to enable autonomous flight by combining various sensors and software tools. In particular, autonomous flight of drones was possible since the application of GNSS-RTK (global navigation satellite system with real-time kinematic positioning), a precision satellite navigation technology. For instance, unmanned drone delivery based on GNSS-RTK data was demonstrated for pizza delivery in Korea for the first time in 2021. However, the vulnerabilities of GNSS-RTK should be overcome for delivery drones to be commercialized. In particular, jamming in the navigation system and low positioning accuracy in urban areas should be addressed. Solving these two problems can lead to stable flight, takeoff, and landing of drones in urban areas, and the corresponding solutions are expected to establish a hybrid positioning technology. We discuss current trends in hybrid positioning technology that can either replace or complement GNSS-RTK for stable drone autonomous flight.

• 한국항공우주학회지
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• 제47권4호
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• pp.266-273
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• 2019

다수의 소형 정찰용 무인항공기를 이용하여 탐색 및 정찰 임무를 수행하는데 있어서 무인항공기의 운용 대수, 비행고도 등 운용 조건에 따라 임무 수행의 효율성과 효과성은 크게 변경될 수 있다. 하지만 어떤 운용조건이 가장 합리적인지 판단하기는 쉽지 않다. 따라서 본 연구에서는 자율비행에 따라 충돌을 회피하면서 표적을 탐지 및 판별할 수 있는 무인항공기 비행 시뮬레이션을 개발하여 다수의 무인항공기 운용 시 보다 효과적이고 효율적인 운용조건을 도출할 수 있는 방안을 제시하였다.

• 항공우주시스템공학회지
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• 제13권3호
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• pp.15-22
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• 2019

본 논문에서는 무인항공기의 자율 비행을 위한 전역 및 지역 경로 비행 시스템을 제안한다. 전체적인 시스템은 ROS 로봇 운영체제를 기반으로 구축하였다. 무인항공기에 탑재된 임베디드 컴퓨터는 2-D Lidar를 이용하여 장애물을 검출하고, 실시간으로 VFH 기반의 지역 경로와 제안하는 Modified $RRT^*$-Smart 기반의 전역 경로를 생성한다. 또한, 무인항공기의 비행컨트롤러에 Mavros 통신 프로토콜을 이용하여 생성된 경로에 따른 이동 명령을 내린다. 지상국 컴퓨터는 장애물 정보를 수신하여 2-D SLAM 지도를 생성하고, 목적 지점을 임베디드 컴퓨터에 전달하며 무인항공기의 상태를 관장한다. 제안하는 무인항공기의 자율 비행 시스템을 3-D 공간 상의 시뮬레이터 및 실제 비행을 통해 검증하였다.