• 한국기계가공학회지
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• 제19권4호
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• pp.85-92
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• 2020

Applications for the unmanned aerial vehicle (UAV) have expanded enormously in recent years. Of all its various technologies, the UAV's ability to take off and land in a moving environment is particularly required for military or oceanic usage. In this study, we develop a novel leveling platform that allows the UAV to stably take off and land even on uneven terrains or in moving environments. The leveling platform is composed of an upper pad and a lower mobile base. The upper pad, from which the UAV can take off or land, is designed in the form of a 2 degrees of freedom (DOF) gimbal mechanism that generates the leveling function. The lower mobile base has a four-wheel drive structure that can be operated remotely. We evaluate the developed leveling platform by performing extensive experiments on both the horizontal terrain and the 5-degree ramped terrain, and confirm that the leveling platform successfully maintains the horizontal pose on both terrains. This allows the UAV to stably take off and land in moving environments.

• 제어로봇시스템학회논문지
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• 제13권1호
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• pp.39-45
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• 2007

This paper proposes a method of container position measurement using automatic landing system that is estimated by a laser range finder. In the most of container position measurement methods, CCD cameras or laser scanners have been used to get the source data. However those sensors are not only weak for disturbances, for examples, the light, fog, and rain, but also the system cost is high. When the spreader arrives at the goal position, it is still swung by inertia or by wind effect. In this paper, the spreader swung data have been used to find the container position. The laser range finder is equipped in the front side of spreader. It can measure distance and relative position between spreader and container. This laser range finder can be rotated as desired by a motor. And a tilt sensor is equipped on the spreader to measure spreader sway. The relative position information between the spreader and a container using the laser range finder and tilt sensor is estimated through the geometrical analysis.

• 한국인터넷방송통신학회논문지
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• 제20권4호
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• pp.93-99
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• 2020

드론 기술의 발전으로 감시, 재난사고 예방 및 구호 등 공공임무 수행에도 지능화된 드론 활용이 급속히 늘어날 것으로 본다. 드론이 스마트 안전도시 플랫폼에 구축에 사용되기 위해서는 목표물 탐지 및 추적기술, 드론비행 시에 비행 조정 및 장애물 회피기능, 착륙지점 탐지 및 제어 기능 등의 주요 기술 구현이 필요하다. 드론 시스템 은 기술적 파급효과가 크고 신기술 분야의 산업화를 촉진한다. 본 논문에서는 이와 같은 드론 개발을 위하여 객체지향 분석/설계 방법을 이용한 요구사항 분석 및 플로우차트, 화면 설계 등을 보여여줌으로 효과적인 드론 시스템의 소프트웨어 분석 및 설계 방법을 제시하고자 한다.

• 디지털콘텐츠학회 논문지
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• 제18권5호
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• pp.889-894
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• 2017

본 논문은 방목형 축산관리의 효율성을 극대화하기 위해 무인비행체 기반의 자동항법과 근거리무선통신망 기술, 자동이착륙 시스템을 및 개체관리 운영 앱을 통하여 스마트팜 구현에 목적이 있다. 산지생태축산 활성화를 위하여 축산 ICT 융합 기술을 접목한 방목 목장 관리 시스템은 방목 가축의 생산성 향상과 우수품질을 생산하는 인프라 조성과 FTA에 대응하는 축산 경쟁력 확보에 기여할 것으로 예상된다. 축산업에 종사하는 부족한 인력을 대체하는 기술로 농가에 보급을 통해 경쟁력 향상에 기여할 것이다.

• 수산경영론집
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• 제50권3호
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• pp.17-29
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• 2019

This paper aims to find out the problems and improvement direction of quality control and hygiene management of fishery products in Korea. For this reason, we conducted a comparative analysis of quality control and hygiene management of fishing, landing and selling between Japan and Korea, taking mackerel as an example. Japan has established a systematic freshness management system from fishing to landing (production) areas and consumption areas. On the other hand, Korea is not fully lead-managed in the production area after fishing, and is distributed in a state where the quality of the product is deteriorated due to exposure to room temperature. Accordingly, a certain quality can not be secured at the final consumption stage, and sanitary problems occur. In order to improve the quality control and hygiene management of the fishery products, the following needs to be improved. First, we will improve the fishing level freshness management system. Second, we will improve the quality control and hygiene management of fish in the production area and wholesale stage. Third, we will promote the introduction of innovative sales and consignment sales systems at the production stage. Fourth, we will establish a consistent low temperature distribution system from the production area to the wholesale stage from a long-term perspective. Fifth, we will promote the development and education of manuals on fish quality and hygiene management.

• Advances in aircraft and spacecraft science
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• 제8권1호
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• pp.17-30
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• 2021

This is an investigation for a more electric regional aircraft, considering the ATR 72 aircraft as an example and the electrification of its four double slotted flaps, which were estimated to require an energy of 540 Wh for takeoff and 1780 Wh for landing, with a maximum power requirement of 35.6 kW during landing. An analysis and evaluation of three energy harvesting systems has been carried out, which led to the recommendation of a combination of a piezoelectric and a thermoelectric harvesting system providing 65% and 17%, respectively, of the required energy for the actuators of the four flaps. The remaining energy may be provided by a solar energy harvesting photovoltaic system, which was calculated to have a maximum capacity of 12.8 kWh at maximum solar irradiance. It was estimated that a supercapacitor of 232 kg could provide the energy storage and power required for the four flaps, which proved to be 59% of the required weight of a lithium iron phosphate (LFP) battery while the supercapacitor also constitutes a safer option.

• 항공우주시스템공학회지
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• 제13권6호
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• pp.43-51
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• 2019

택싱모드 상태에서 노면의 가진으로 발생하는 기체 가속도는 조종사와 탑승객의 탑승감을 해치는 주 요인이다. 본 논문에서는 MR댐퍼 착륙장치의 탑승감을 향상시키기 위해 제어기법을 연구하였다. 제안된 제어기법은 Skyhook Control Type2 로 기존의 스카이훅 제어와는 달리 추가적으로 상부질량가속도를 피드백 받아 제어력을 구성한다. Skyhook Control Type2는 상부질량의 속도와 가속도를 모두 고려하기 때문에 상부질량속도만을 고려하는 스카이훅 기법의 제어한계를 개선하는 효과가 있다. 시뮬레이션을 위해 범퍼형태의 노면을 활주노면으로 선정하였으며, 리커다인(RecurDyn)으로 구성한 착륙장치 모델과 시뮬링크(Simulink)로 설계한 제어기를 연동해석 하였다. 시뮬레이션을 통해, 상부질량가속도의 RMS값과 최대값을 활주속도 및 제어기법에 따라 비교 분석하여 Skyhook Control Type2에 대한 제어효과를 검증하였다.

• 한국해안해양공학회지
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• 제17권2호
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• pp.70-79
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• 2005

국내 잔교식 안벽의 거의 대부분은 연직말뚝과 함께 경사말뚝을 활용하고 있는데, 정적인 상태의 횡방향 지지 효과를 크게 볼 수 있는 경사말뚝을 잔교식 안벽 구조물에 적용하는데 있어 말뚝 두부에 면진장치를 설치함으로써 내진성능 또한 증대시키고자 하는 시도가 꾸준히 이어져 오고 있다. 본 연구에서는 잔교식 안벽 중 경사말뚝의 내진성능 증대를 위한 목적으로 말뚝 두부를 고무 또는 볼베어링을 이용하여 보강하는 시스템을 개발하고, 진동대 실험 및 3차원 수치해석으로부터 새로운 개념의 두부보강기법에 따른 내진성능 평가를 수행하였다 진동대 실험 및 수치해석 결과로부터 새로운 두부보강기법의 내진성능 효과를 파악하였고, 또한 고무와 볼베어링 시스템의 비선형성을 고려한 3차원 수치해석의 신뢰성을 확인하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.167.2-167
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• 2001

This paper presents guidance and control laws which guarantee a minimum fuel consumption and have obustness against various disturbances during a terminal-landing phase on the lunar surface. The nonlinear robust tracking control system is designed to track the reference profiles, which are expressed by exponential functions. An adjustment law in the tracking controller is given in the form of the differential equations with respect to the controller´s variable gains. Computer simulations are performed to examine the tracking accuracy, the robustness in a thrust failure mode, and the vertical soft landing at a pre-assigned point on the lunar surface. The results of numerical simulation show the effectiveness of the present control law.

• International Journal of Precision Engineering and Manufacturing
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• 제9권3호
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• pp.72-74
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• 2008

We investigate the effect of mechanical damping and electrical conductivity on the dynamic performance of a new electromagnetic engine valve actuator that employs a permanent magnet. The key dynamic performance factors are the transition time and the landing velocity of the armature. Two-dimensional dynamic finite element analyses are performed to simulate a coupled system. The results show that mechanical damping and electrical conductivity have similar effects on the dynamic performance of the engine valve actuator. Subsequently, it is possible to replace the role of mechanical damping by controlling the electrical conductivity through the thickness and number of steel core laminations.