• Journal of Advanced Navigation Technology
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• 제19권6호
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• pp.473-483
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• 2015

This paper reports the single-input-single-output cascade control by using 1-axis attitude control test-bench for quad-rotor UAV. The test-bench was designed as a see-saw shape using 2 motors and propellers, and to enable changing the center of gravity with the center of gyration using ballast. The experiment was carried out by constructing a PID-PID controller having a cascade structure with the test-bench. The SIMC based PID gain tuning process, which makes PID gain tuning easy, was grafted to cascade control. To graft SIMC method, the system parameter estimation result was conducted with second order time delay model by using Matlab-Simulink. Gain tuning was conducted by simulating with estimated system parameter. In this paper, the conventional application of SIMC was conducted and improved application was proposed for improving stability at tuning process.

• Proceedings of the Korean Vacuum Society Conference
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.468-468
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• 2014

우리나라는 미국, EU, 러시아, 중국, 인도 등 다국간 협력 사업인 국제핵융합실험로(ITER) 사업에 참여하고 있으며, 블랑켓 일차벽 및 시험용 블랑켓 모듈(Test Blanket Module, TBM) 제작기술 개발에 필요한 고열부하 검증시험을 국내에서 자체적으로 실시하기 위한 고열부하시험 시설을 구축하였다. 한국원자력연구원에 설치된 고열부하시험 시설의 주요 사양은 다음과 같다. 열원으로는 전자빔을 사용하며, 빔출력은 최대 300 kW이고, 최대 출력밀도는 $10GW/m^2$이다. 전자빔의 최대 가속전압은 60 kV이고, 최대 조사 면적은 설계상 $70cm{\times}50cm$이다. 고열부하 장비는 핵융합환경과 유사한 고열부하를 시험대상물에 인가하여 접합 및 냉각 성능을 평가하는 장비이며, ITER 블랑켓 및 TBM 일차벽의 경우 약 $0.5MW/m^2$, 가속실험 혹은 사고 시 순간 시나리오 해석을 위해서 $5MW/m^2$까지 고려되기도 한다. ITER 블랑켓 일차벽 제작기술 개발 및 검증(2004~2011)에서는 외국장비(러시아 TSEFEY, 일본 JEBIS, 독일 JUDITH)를 활용하였으나, 고비용 문제와 장비 이용 시간의 제한에 따라 사용이 어려워, 국내에서는 KoHLT-1, 2 장비를 자체 구축하여 활용하여 왔다. 현재는 높은 열부하 인가조건, 약 $5MW/m^2$을 달성하기 위해서 전자빔을 이용한 고열부하시험 장치를 마련하였으며, ITER 블랑켓 일차벽 Semi-Prototype 검증시험, TBM, KSTAR 디버터 실험 등 핵융합로 일차벽 개발에 활용하고 있다. 전자빔, 전원 및 진공 chamber 등 전체 고열부하 시험장치를 구축하여 ITER 장치를 포함해서 토카막 디버터 등 핵융합 플라즈마 대면부품 (Plasma Facing Components, PFC) 재료 개발과 국방, 항공우주 분야의 열유속 게이지 측정법 향상 연구, 로켓 추진 엔진 연소실의 열유속 모니터링 연구, 항공기 프로펠러 연구 등에 활용할 수 있을 것으로 기대된다.

• Korean Journal of Fisheries and Aquatic Sciences
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• 제18권1호
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• pp.8-14
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• 1985

A circulation water channel with observational section of $4m{\times}2.4m{\times}1m(length{\times}breadth{\times}depth)$ and the maximum channel flow speed of 2 m/sec was designed for model tests of fishing gears. It consists of 6 sections evenly divided for easy connection. Two observational acryl windows of $1.2m{\times}1.5m$ and 2cm thick are provided. Steel deflection plates, equally spaced in 20-40cm, are fixed at corners of the channel to reduce the loss of water pressure head through the channel. The flow in the channel is controlled by D.C. motor control system with 50 H.P. driving propeller system. A series of model testing capabilities for fishing gear have been examined and the results are as follows. 1) The speed of water flow was in the range from zero to 2.3 m/sec. 2) The difference between the velocity of channel flow along the center line and that along both sides in the channel was less than 0.2 m/sec.

• Journal of the Korean Society of Marine Environment & Safety
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• 제20권5호
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• pp.552-557
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• 2014

The objective of the This study is to access the speed performance employing the sea trial test and CFD with the our own designed and manufactured one-man boat. The overall design process including hull form design was explained. The sea trial was carried out with a manufactured boat in the clam sea. Brake power at the design speed of a boat through the sea trial was measured as 1680 W. The flow computation was conducted considering free surface and dynamic trim using a commercial CFD code(STAR-CCM+). The result of computation provided the information that residual resistance is bigger than fraction's at design speed. The total efficiency were predicted based on the sea trial and CFD. The Total efficiency was divided into shaft efficiency and quasi-propulsive efficiency. By using quasi-propulsive efficiency, it becomes possible to predict speed performance of boat in future. The results can provide information regarding hull form design, performance analysis and development of a boat in future.

• Journal of Practical Engineering Education
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• 제10권1호
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• pp.17-24
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• 2018

Through the design and production of works for the third semester as a major unit, It is proposed the process of satisfying the graduation standards with the design and production process of the drone which can be applied to various mobile environments. Using the shape of Ring Propeller, it is made to be able to play both the role of generating lift as a propeller and the role of a wheel that touches the ground through the surface of the rim. In addition, the Servo Motor is used to convert the drive shaft of the motor to the correct angle according to the command. Then, based on the idea, the 3D printing is implemented to confirm the result of the configuration, and the circuit for driving the propulsion is designed and manufactured. As a result, the conversion of the desired propulsion system during air navigation and operation failed due to the weight increase of the propellant. It is confirmed that the size of the thrust and the tolerance limit of the ring propeller are the errors. Through these processes, it has been recognized to have experience of creative thinking and cooperation through engineering approach and comprehensive design, and confirmed to satisfy the graduation criteria by writing an engineering paper on the result.

• Journal of Korean Society of Coastal and Ocean Engineers
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• 제20권2호
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• pp.232-237
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• 2008

A method to generate electric power from small scale water tank. For this purpose, manufacturing tank is investigated, measuring water level change at any time, and finally comparing experimental and theoretical value, are performed. Inner and outer tank are made to simulate flood and ebb generation. Two sets of pipe are connected between tanks, and experiments are performed under varying flowrate. Coefficients of flowrate are calculated comparing water level change data and theoretical value. Measured and theoretical water levels are highly correlated, and this ascertains that analytical equation simulates real water level changes well. Flowrate change depending on the existence of propeller and valve, on flood and ebb generation, shows the necessity of experiments in the process of manufacturing electric power system. Moreover, total energy calculated from experimental data agrees well with that of theoretical equation. In spite of small tidal power output, this generating system with optimum water tank can be applied to any place where high water level change occurs, and can make a contribution to producing new and renewable energy consequently.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 한국표면공학회 2016년도 추계학술대회 논문집
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• pp.142-142
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• 2016

무전해 니켈 도금은 산업기계 부품, 자동차 부품, 항공 및 전자 통신 부품 등에 이르기까지 산업 전반에서 폭넓게 사용되고 있다. 이는 무전해 니켈 도금 층이 우수한 균일성, 내마멸성, 내식성 등을 지녀 관련 연구가 지속적으로 활발하게 진행되어 왔기 때문이다. 특히, 최근에 이르기까지 도금 층이 얇고, 우수한 내마멸성 및 낮은 마찰계수를 활용한 무전해 니켈 도금은 산업현장에서 기계 부품들의 수명을 연장시키고, 그 성능을 개선시키는데 용이하게 적용되고 있다. 본 연구에서는 이와 같이 무전해 니켈 도금 층의 우수한 특성을 활용하여 해수 부식과 캐비테이션-침식 복합 환경 하에 놓여 있는 금속 재료의 손상을 방지하고자 하였다. 이는 선박의 경우 최근 고속화, 대형화 추세에 따라 부품의 내구성 향상과 연비 효율성이 더욱 강조되고 있으며, 그에 따라 해수 속에서 고속 회전으로 더욱 가혹해진 캐비테이션 침식-부식 환경하에 놓인 선박의 프로펠러, 펌프 임펠러 및 케이싱 등의 금속재료 자체를 보호할 수 있는 고성능 재료의 개발이 요구되고 있기 때문이다. 또한 해양환경 하에서 무전해 니켈 도금 층에 대한 캐비테이션 침식 손상에 대한 연구는 미비한 실정이다. 본 연구에서는 회주철 표면에 무전해 니켈 도금을 실시하여 캐비테이션 침식 손상을 방지하고자 하였다. 무전해 니켈 도금을 실시하기 전 도금 층을 균일하게 형성하기 위해 샌드 페이퍼 #1200까지 연마 후 알칼리 탈지 실시하고, 산세(10% HCl)와 수세를 순차적으로 실시하여 전처리하였다. 이후 무전해 니켈 도금은 황산니켈, 차아인산나트륨, 구연산, 아세트산나트륨 그리고 미량의 질산납으로 구성된 도금욕에서 pH 4-6, $80-90^{\circ}C$의 조건으로 실시하였으며, pH는 NaOH를 이용하여 조정하였다. 이렇게 제작된 무전해 니켈 도금 층에 대하여 천연 해수 속에서 ASTM-G32 규정에 의거한 캐비테이션 침식실험을 통해 내구성을 평가하였다. 캐비테이션 실험 후에는 무게 감소량, 표면 손상깊이, 침식 손상 경향 등을 종합적으로 분석 비교하였다. 그 결과, 회주철에 대하여 무전해 니켈 도금을 실시할 경우 현저한 캐비테이션-침식 저항성 향상이 관찰되었다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 한국항해항만학회 2016년도 춘계학술대회
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• pp.98-99
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• 2016

The aim of study is to develop a dual driven ship berthing/deberthing system with $360^{\circ}$ steerability. A large ship used bow thruster, side thruster and pod propulsor etc. when approaching to a pier. But as marine leisure boats become large-scaled, the number of accidents is recently increasing what caused a ship to crash into a ship and a ship to crash into mooring facilities during berthing/deberthing on a marina. To solve the problem, the control responsiveness of a joystick connected with two motors and a propeller was checked and torque was increased by the electromagnetic design of magnetic gear. A sea trial test was carried out to investigate a performance of the developed system in the real sea.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제42권1호
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• pp.37-46
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• 2014

This paper describes the conceptual design and development test procedure of a unmanned scaled-down personal air vehicle(PAV) with drive and flight dual mode capability. Trade studies on operational requirements led to the suggestion of a quad tilt prop platform which has nacelle tilt capability with multi rotor configuration. Motors for propeller propulsion and driving mechanism were integrated into a single nacelle, then they were implemented by nacelle tilt mechanism for conversion between the drive and the flight modes. Primary design parameters and initial specifications were confirmed through conceptual design, then functional tests were performed with the test platforms for the drive and the flight modes.

• Journal of the Korean Society of Marine Environment & Safety
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• 제23권5호
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• pp.595-602
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• 2017

In Korea, much research and development have occurred to enhance the technological competitiveness of tuna purse seining fisheries. Due to these efforts, fishing efficiency has been improved with the development of radar, sonar and global positioning systems for fish detection and revisions to the hull forms of tuna purse seiners. However, for skiff boats, net boats and speed boats, which are auxiliary working boats mounted on tuna purse seiners, technology has lagged behind relative to the modernization of the main vessel. In this study, the hull of an existing propeller-based net boat with steel wire net to protect tuna was changed to the hull of a water jet propulsion vehicle to reduce resistance and improve maneuverability. As a result, a prototype of a water jet propulsion option was produced according to the aluminum structure strength standards specified by the Ministry of Oceans and Fisheries, and safety was confirmed by performing a drop test. Moreover, through a sea trial test, an existing net boat was shown to have a speed of 12.0knots and a towing force of 2,545 kgf at 2,500 RPM. The prototype had a speed of 26.7 knots and a towing force of 2,011 kgf at 3,200 RPM, which satisfied the towing capacity standards of auxiliary working boats mounted on tuna purse seiners.