• The Journal of Korea Robotics Society
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• v.16 no.2
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• pp.155-163
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• 2021

In this paper, we propose a four 2-link robotic leg landing system that is used for leveling the bottom of the landing system, even when the quadcopter posture is changed. The case of conventional skid type landing gear has a risk when the quadcopter lands on a moving vehicle because the skid type landing gear is tilted to the landing site at this situation. To solve this problem, it is necessary to level the bottom of the landing system when the quadcopter posture is changed in the flight. Therefore, the proposed landing system used a four 2-link robotic leg with leveling method. The leveling method was derived from the method of determining a plane. The superiority of the proposed system was verified with 6-axis stewart platform and real flight experiment, and it shows feasibility of leveling method and proposed landing system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.3
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• pp.1224-1242
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• 2018

Aiming at motion analysis and compensation, it is essential to conduct motion detection with images. However, motion detection and tracking from low-altitude images obtained from an unmanned aerial system may pose many challenges due to degraded image quality caused by platform motion, image instability and illumination fluctuation. This research tackles these challenges by proposing a modified joint transform correlation algorithm which includes two preprocessing strategies. In spatial domain, a modified fuzzy edge detection method is proposed for preprocessing the input images. In frequency domain, to eliminate the disturbance of self-correlation items, the cross-correlation items are extracted from joint power spectrum output plane. The effectiveness and accuracy of the algorithm has been tested and evaluated by both simulation and real datasets in this research. The simulation experiments show that the proposed approach can derive satisfactory peaks of cross-correlation and achieve detection accuracy of displacement vectors with no more than 0.03pixel for image pairs with displacement smaller than 20pixels, when addition of image motion blurring in the range of 0~10pixel and 0.002variance of additive Gaussian noise. Moreover,this paper proposes quantitative analysis approach using tri-image pairs from real datasets and the experimental results show that detection accuracy can be achieved with sub-pixel level even if the sampling frequency can only attain 50 frames per second.

• Journal of Aerospace System Engineering
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• v.17 no.5
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• pp.34-41
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• 2023

This paper applies the icing effect and wing rock uncertainty to small unmanned aerial vehicles (UAVs), which have recently attracted attention. Attitude control simulations were performed using various control methods. First, the selected platform, the Skywalker X8 UAV with blended wing-body (BWB) configuration, was linearized for both its baseline form, and a form with applied icing effects. Subsequently, using MATLAB SimulinkⓇ, simulations were conducted for roll and pitch attitude control of the baseline configuration and the configuration with icing effects, employing disturbance observer-based PID control, model reference adaptive control, and model predictive control. Furthermore, the study introduced wing rock uncertainty simultaneously with icing effects on the configured model-a combination not previously explored in existing research-and conducted simulations. The performance of each control Method was compared and analyzed.

• Journal of Korea Multimedia Society
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• v.11 no.11
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• pp.1525-1535
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• 2008

High Altitude Platform (HAP) based networks deploy network infrastructures of Mobile Base Station (MBS) in a form of Unmanned Aerial Vehicle (UAV) at stratosphere in order to build network configuration. The ultimate goal of HAP based network is a wireless network service for wide area by deploying multiple MBS for such area. In this paper we assume multiple UAVs over designated area and solve the MBS placement and coverage problem by clustering the mobile ground nodes. For this study we assumed area around Cheju island and nearby naval area where multiple mobile and fixed nodes are deployed and requires HAP based networking service. By simulation, visual results of stratospheric MBS placement have been presented. These results include clustering, MBS placement and coverage as well as dynamic reclustering according to the movement of mobile ground nodes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.56-62
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• 2017

As the need for 3D spatial information increases, many local governments and related industries are establishing map-based 3D spatial information services and offering them to users. In these services, positional accuracy is one of the most important factors determining their applicability to specific tasks. This study studied the location correction method between indoor and outdoor 3D spatial information through the construction of modeling data on a BIM/GIS platform. First, we selected the sites and processed the BIM/GIS data construction with 3 steps. When connecting the BIM model including indoor spatial data and 3D texturing model based on ortho images, mismatches occurred, so we proposed a location correction method. Using the conversion algorithm, the relative coordinate-based BIM data were converted to the absolute positions and then relocated by means of the texturing data on the BIM/GIS platform.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.984-989
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• 2003

The integrated global position system (GPS) and inertial navigation system (INS) has been considered as a cost-effective way of providing an accurate and reliable navigation system for civil and military system. Even the integration of a navigation sensor as a supporting device requires the development of non-traditional approaches and algorithms. The objective of this paper is to assess the feasibility of integrated with GPS and INS information, to provide the navigation capability for long term accuracy of the integrated system. Advanced algorithms are used to integrate the GPS and INS sensor data. That is fuzzy inference system based Weighted Extended Kalman Filter(FWEKF) algorithm INS signal corrections to provided an accurate navigation system of the integrated GPS and INS. Repeatedly, these include INS error, calculated platform corrections using GPS outputs, velocity corrections, position correction and error model estimation for prediction. Therefore, the paper introduces the newly developed technology which is aimed at achieving high accuracy results with integrated system. Finally, in this paper are given the results of simulation tests of the integrated system and the results show very good performance

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.12
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• pp.1095-1102
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• 2016

This paper presents the results of the design, fabrication and tether test for a gross weight 20 kg tilt-duct VTOL aerial robot. The tilt-duct vehicle, a tri-ducts air-vehicle, which composed of two main tilt ducts for thrust and an aft-fan for pitch attitude control, has been developed as an aerial platform. The research on the air vehicle has been focused on the hover characteristics and controllability to improve the thrust and stability. The tether test for measuring various performance of vehicle and evaluating controllability have been carried out to figure out effects of modified main-prop linkage, actuator, duct configuration and control surfaces.

• Journal of the Korea Society for Simulation
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• v.27 no.2
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• pp.101-114
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• 2018

Several different approaches and mechanisms are introduced to solve the UAV path planning problem. In this paper, we designed and implemented an agent-based simulation software using the Repast platform and Java Genetic Algorithm Package to examine an evolutionary path planning method by implementing and testing within the Repast environment. The paper demonstrates the life-cycle of an agent-based simulation software engineering project while providing a documentation strategy that allows specifying autonomous, adaptive, and interactive software entities in a Multi-Agent System. The study demonstrates how evolutionary path planning can be introduced to improve cognitive agent capabilities within an agent-based simulation environment.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.342-342
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• 2020

최근 소형 무인비행장치(UAV; unmaned aerial vehicle)인 드론을 이용한 신산업 육성 및 지원에 관한 관심도가 높아지고 있다. 국외에서는 이미 드론을 이용한 농업관리와 물류배송, 공공부문 모니터링 등 다양한 산업 분야의 드론 이용을 적극 장려하고 있다. 드론 이용에 관한 관심도가 높아짐에 따라 국내외적으로 드론 응용 관련 기술 개발과 연구가 활발하게 진행되고 있지만, 국내에서는 환경모니터링과 시설물 점검 등 일부 제한적으로 활용되고 있다. 국내에서는 2024년까지 드론 응용서비스로 확장되는 산업 변화에 대응, DNA(Data, Network, AI) 기술을 접목한 새로운 개방형 플랫폼 구축을 목표로 기술개발 및 산업 육성을 촉진하고 있다. 이러한 국내 기술 개발 방향에 맞추어 드론과 첨단기술을 이용한 하천조사와 관련해 드론을 연계한 하천관리 플랫폼 개발의 필요성이 높아지고 있다. 본 연구에서는 드론 기반 하천조사 및 모니터링 수행을 위한 하천관리 운영플랫폼 개발을 목표로 국내외 요소기술을 분석하고 기술수준을 조사했다. 특히, 드론 기반 하천관리에 필요한 임무를 영역별로 분리해 요소기술 기반의 플랫폼 서비스를 정의하고 하천관리 부문 개방형 플랫폼 구축을 위한 시스템 구성 및 운영에 필요한 요소기술을 선정했다. 최종적으로 선정된 플랫폼 서비스와 요소기술을 기초로 시스템 적용방안을 검토하고 하천관리 운영플랫폼 구축을 위한 시스템 아키텍처를 정의 및 설계했다.

• Journal of Aerospace System Engineering
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• v.18 no.2
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• pp.47-55
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• 2024

The paper presents a docking-type automatic landing system that works in tandem with Unmanned Aerial Vehicles (UAVs) and Unmanned Surface Vehicles (USVs). The system utilizes a pyramid-shaped landing gear and pad for effective landing. In marine environments, a docking device guides the drone to land securely. To test the system, a ship's behavior was simulated using a 3-DoF motion platform, and the successful operation and utility of the docking-type automatic landing system were demonstrated.