• 제어로봇시스템학회논문지
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• 제21권11호
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• pp.1027-1033
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• 2015

For the attitude control of spacecraft, two variable-speed control moment gyros are proposed as main actuators in the article. Since a variable-speed control moment gyro (VSCMG) makes two control torques (gyroscopic torque and reaction torque), two VSCMGs are sufficient for controlling 3-axes attitude. Additionally, there are no singular conditions for two non-parallel VSCMGs. Since gyroscopic torque is usually much greater than reaction torque, the control performances of approximately 3 axes may not be the same. However, several missions can be accomplished by controlling two axes. For such missions, a selective axes control method is proposed. The method selects two axes for a certain task and controls the attitude of the selected axes. For the remaining axis, angular speed is controlled for stabilization. A hardware-in-the-loop simulation has been used to test VSCMG modules and to verify the proposed method. Two VSCMGs can be alternative actuators for small satellites.

• 항공우주산업기술동향
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• 제9권1호
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• pp.102-109
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• 2011

지구근접물체는 궤도상에 인접한 행성들의 만유인력으로 인해 지구 부근으로 진입할 수 있는 혜성과 소행성이다. 일정 크기의 혜성과 소행성이 지구 표면과 충돌하면 심각한 재난이 발생할 수 있다. 그러나 지구에 가까이 접근하여 잠재적으로 매우 위험할 수도 있는 이 지구근접물체는 원자재로써도 가장 쉽게 채굴될 수 있는 대상이다. 본 논문에서는 우주근접물체에 대한 특징과 우주 선진국들의 인공위성을 이용한 혜성과 소행성의 우주 탐사에 대한 기술 동향을 기술하였다.

• 로봇학회논문지
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• 제13권4호
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• pp.220-229
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• 2018

In the midst of disaster, such as an earthquake or a nuclear radiation exposure area, there are huge risks to send human crews. Many robotic researchers have studied to send UGVs in order to replace human crews at dangerous environments. So far, two-dimensional camera information has been widely used for teleoperation of UGVs. Recently, three-dimensional information based teleoperations are attempted to compensate the limitations of camera information based teleoperation. In this paper, the 3D map information of indoor and outdoor environments reconstructed in real-time is utilized in the UGV teleoperation. Further, we apply the LTE communication technology to endure the stability of the teleoperation even under the deteriorate environment. The proposed teleoperation system is performed at explosive disposal missions and their feasibilities could be verified through completion of that missions using the UGV with the Explosive Ordnance Disposal (EOD) team of Busan Port Security Corporation.

• 한국항공운항학회지
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• 제27권3호
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• pp.1-14
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• 2019

Cooperative systems among various unmanned vehicles are widely used in various field and emerging. Unmanned vehicles are able to operate various missions without operator onboard and they are highly stable. Collaborative work of multiple unmanned vehicles is emphasized due to the difficulty of recent missions such as SEAD (Suppression of the Enemy Air Defenses), MUSIC (Manned Unmanned Systems Integration Capability), goldentime in the rescue mission. In this study, ROS and Pixhawk were proposed as a method of construction of a collaboration system and framework for an integrated simulation environment for heterogeneous unmanned vehicles is proposed. Totally 5 unmanned vehicles were set for the simulation for the observation of illegal fishing boats. This paper shows the feasibility of the cooperative system using ROS and Pixhawk through the simulation and the experiment.

• 항공우주시스템공학회지
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• 제15권2호
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• pp.36-44
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• 2021

Unmanned aerial vehicles (UAVs) are increasingly needed as they can replace manned aircrafts in dangerous military missions. However, because of their low autonomy, current UAVs can execute missions only under continuous operator control. To overcome this limitation, higher autonomy levels of UAVs based on autonomous situational awareness is required. In this paper, we propose an autonomous situational awareness software consisting of situation awareness management, threat recognition, threat identification, and threat space analysis to detect dynamic situational change by external threats. We implemented the proposed software in real mission computer hardware and evaluated the performance of situational awareness toward dynamic radar threats in flight simulations.

• 한국항공우주학회지
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• 제49권12호
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• pp.997-1010
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• 2021

본 연구는 스페이스 X사의 팔컨 9 발사체의 비행 데이터를 수집하였고 분석하였다. 모든 임무는 극궤도, SSO, ISS, LEO, GTO와 같은 궤도의 종류에 따라 분류하였다. 1단 발사체의 메인 엔진 종료, 역추진, 재진입, 착륙 연소의 특징적인 기동에서 속도, 고도, 동압, 가속도 등의 물리 변수의 변화를 조사하였다. 상세한 기동 분석으로부터 가이드라인을 제안하였고 이는 재사용 발사체 개발을 위한 설계 및 평가 기준으로 사용될 수 있다.

• International Journal of Internet, Broadcasting and Communication
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• 제15권1호
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• pp.211-221
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• 2023

After COVID-19, various metaverse platforms for online lectures are being provided. Most of the classrooms are tiered type, and they are divided into intensive classrooms and open classrooms depending on the shape of the classrooms. Intensive classrooms provide a one-sided lecture format, so there are many difficulties in conducting communication-based classes that carry out team missions like PBL classes. In this study, we propose a metaverse classroom that applies the functions of a multiplayer online role-playing game (MMORPG), one of the game genres suitable for PBL classes. The proposed system provides various interaction techniques for PBL classes. We evaluated user satisfaction when this was applied to actual classes. As a result of the evaluation, it was found that users preferred text and voice chatting more than video chatting and solving missions like games was very helpful in online classes.

• 항공우주의학회지
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• 제30권3호
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• pp.113-129
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• 2020

With the operation of the KC-330 MRTT (Multi Role Tanker Transport), which had been fielded in 2019, the ROKAF (Republic of Korea Air Force) has given fighter pilots a new mission of air refueling. As a result, fighter pilots are more likely to be exposed to risks they have never faced before, and it is necessary to look at the risk factors associated with human factors in air refueling missions. Therefore, in this study, an analysis using the HFACS (Human Factors Analysis and Classification System) model was performed for fighter pilots with air refueling qualifications. This study tried to prevent hazard in advance by discriminating the risk factors according to the human factors related to the fighter pilot during the air refueling mission.

• 로봇학회논문지
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• 제18권3호
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• pp.233-240
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• 2023

In this paper, we proposed a hybrid type robot that simultaneously surveillance and reconnaissance on the ground and in the air. It was possible to expand the surveillance and reconnaissance range by expanding the surveillance and reconnaissance area of the ground robot and quickly moving to the hidden area through the drone. First, ground robots go to mission areas through drones and perform surveillance and reconnaissance missions for urban warfare or mountainous areas. Second, drones move ground robots quickly. It transmits surveillance and reconnaissance images of ground robots to the control system and performs reconnaissance missions at the same time. Finally, in order to secure the interoperability of these hybrid robots, basic performance and environmental performance were verified. The evaluation method was tested and verified based on the KS standards.

• 산업경영시스템학회지
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• 제46권4호
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• pp.238-245
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• 2023

As technologies have been more quickly developed in this 4th Industry Revolution era, their application to defense industry has been also growing. With these much advanced technologies, we attempt to use Manned-Unmanned Teaming systems in various military operations. In this study, we consider the Location-Routing Problem for reconnaissance surveillance missions of the maritime manned-unmanned surface vehicles. As a solution technique, the two-phase method is presented. In the first location phase, the p-median problem is solved to determine which nodes are used as the seeds for the manned vehicles using Lagrangian relaxation with the subgradient method. In the second routing phase, using the results obtained from the location phase, the Vehicle Routing Problems are solved to determine the search routes of the unmanned vehicles by applying the Location Based Heuristic. For three network data sets, computational experiments are conducted to show the performance of the proposed two-phase method.