• 한국광학회지
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• 제18권1호
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• pp.31-36
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• 2007

직경과 초점거리가 수 mm인 카메라폰 렌즈의 성능을 평가하는 변조전달함수(Modulation Transfer Function: MTF) 측정장치를 개발 하였다. 전체 측정장치는 물체부, 상분석부, 렌즈 마운터로 구성되며, 물체부는 비축상 측정을 위하여 회전한다. 렌즈의 정밀한 정렬을 위하여 정밀한 수평형 거치대를 제작하였으며 광축 조정과 렌즈의 기울어짐 등의 문제를 매우 효과적으로 개선하였다. 시험렌즈의 초기정렬이 끝나면 자동으로 MTF를 측정하며 측정시간은 10초 이내이다.

• 전력전자학회논문지
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• 제13권4호
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• pp.295-302
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• 2008

본 논문에서는 세탁기용으로 사용될 영구자석형 릴럭턴스 동기전동기(permanent-magnet assisted reluctance synchronous motor : PMA-RSM)의 설계와 특성에 대해서 살펴본다. 제안된 PMA-RSM의 특성과 최대 토크 특성을 알아보기 위해서 유한 요소법(finite element method)을 이용 하였다. 저속 구간에서의 충분한 토크를 발생시키기 위해서 회전자의 구조는 릴럭턴스 토크를 만들어내는 돌극 구조와 회전자 내부의 공극에 영구자석을 삽입하는 구조로 구성되어 있다. 전형적인 자속 장벽형(Flux barrier type) 릴럭턴스 동기전동기(RSM : Reluctance Synchronous Motor)와 자속 장벽(Flux barrier)에 자석을 삽입한 경우에 발생되는 현상들에 대해서 비교 분석하고, 또한 제안된 PMA-RSM의 릴럭턴스 토크(reluctance torque)와 자석에 의한 자석 토크(magnetic alignment torque)가 서로 최대가 되는 시점을 시뮬레이션을 통하여 구하며, 그 결과를 이용하여 전동기의 특성, 평균토크 그리고 토크 리플에 대해서 유한 요소법을 통하여 살펴보았다.

• 한국인터넷방송통신학회논문지
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• 제11권5호
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• pp.35-40
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• 2011

본 논문에서는, 무선 전력전송 방식을 이용한 이동로봇의 자동 충전 시스템을 개발한다. 기존 이동로봇의 자동 충전이 기구적 접촉에 의해 이루어졌던 것에 비해, 무선 전력전송을 이용한 충전 방법은 전자기 유도 방식에 의한 비접촉 충전시스템이다. 이 방식은 송수신 코일이 바른 위치에 정렬되어야만 효율적인 충전이 가능하다. 이 문제를 해결하기 위하여, 영상정보를 통해 충전시스템의 원형 송신 코일의 변형률을 인식하여, 효율적인 자동충전이 가능하도록 이동로봇의 자세를 제어한다.

• 동력기계공학회지
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• 제15권4호
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• pp.25-30
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• 2011

This study is made to provide with a method for correcting the geometric distortion of the digital radiography image by analytical approach based upon the inverse square law and Beer's law. This study is aimed to find out and improve a mathematic model of nonlinear type. Variations in the alignment of the X-ray source, the object, and imaging plate affect digital radiography images. A model which is expressed in parameter values; e.g, angle, position, absorption coefficient, length, width and pixel account of radiography source, is developed so as to match the sample image. For the best correction of the digital image that is the most similar to the model image, a correction technique based upon tangent is developed; then applied to the digital radiography images of steel tubes. As a result, the image correction is confirmed to be made successfully.

• 동력기계공학회지
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• 제10권2호
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• pp.99-103
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• 2006

The laser interferometer has been used for measurement of the micro displacement error. Although the laser interferometer is widely accepted as a tool for measurement of motion accuracy, the set-up procedure is time-consuming because of the strict requirement on alignment between a laser head and optic units. This paper addresses the development of a laser interferometer to measure the micro displacement for a micro machine. The portable laser interferometer which integrates a laser probe and optics, is developed for the convenient measurement. For the experiment, moving mirror set up on the micro stage. The velocity decoding board is also added to calculate doppler shift frequency directly. The output signal is obtained and analyzed by LabView. Finally experiments are found out the relation between micro displacement and output signal.

• 유공압시스템학회논문집
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• 제8권3호
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• pp.14-20
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• 2011

This study aims at aligning multiple wafers to reduce wafer handling time in wafer processes. We designed a multilevel structure for a prealigner which can handle multiple wafer simultaneously in a system. The system consists of gripping parts, kinematic parts, vacuum chucks, pneumatic units, hall sensors and a DSP controller. Aligning procedure has two steps: mechanical gripping and notch finding. In the first step, a wafer is aligned in XY directions using 4-point mechanical contact. The rotational error can be found by detecting a signal in a notch using hall sensors. A dual prealigner was designed for 300mm wafers and constructed for a performance test. The accuracy was monitored by checking the movement of a notch in a machine vision. The result shows that the dual prealigner has enough performance as commercial products.

• 한국생산제조학회지
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• 제21권1호
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• pp.116-122
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• 2012

The purpose of this study is on the development of 3-D conductive pattern fabrication system using laser. For development 3-D direct patterning system, we used the dynamic focusing, the laser power stabilizer and the auto aligning techniques. These technologies are already used commercially. However operation and control integrated system for 3-D direct patterning are not yet developed. The objective of this paper is to introduce laser direct structuring and develop the operating and integration system. Also we implemented new application of laser direct structuring.

• International Journal of Aeronautical and Space Sciences
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• 제18권3호
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• pp.588-600
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• 2017

We develop a wireless, contact free power transfer mechanism that is safer than the direct metallic contact and robust to imperfect alignment on landing at the base station. A magnetic field is created using inductors on both the transmitting and receiving sides. We use the inductive wireless recharging to increase autonomy and decrease the sensor interference by reducing the inductor loop size. By locating four independent small receiver loops and corresponding four circuits around the quadrotor UAV, we can increase safety from circuit malfunctions in comparison to the use of just one loop. On the base station, four folding robotic bars are used to realign the receiver loops over the transmitter loops. After adequate recharging as measured by battery voltages or power consumption at the bae station, the UAV sends a signal to the base station to open the robotic bars and takes off once freed from the robotic bars.

• 전기학회논문지P
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• 제65권3호
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• pp.224-234
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• 2016

This study developed the conductivity pattern of solid surface using laser direct pattern and compound polymer material technology. For development direct patterning system of solid surface, we used the laser power stabilizer, the dynamic focusing, 3D scanner S/W and the auto aligning techniques. Also For conductivity pattern, we are developed compound polymer material with additive by electro-less plating. These technologies are already used commercially. However operation and control integrated system for direct patterning of solid surface are not yet developed. The objective of this paper is to introduce the laser direct structuring for simple process improvement instead complex PCB process, and develop the operating stability and integration system. Also we implemented new application of laser direct structuring through sample manufacture.

• Journal of Magnetics
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• 제20권1호
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• pp.91-96
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• 2015

As many researchers are relentlessly trying to improve the power generation schemes from the power grid, to meet the constantly increasing electricity demand. In this paper, the results of a finite element analysis are carried out to study on a design optimization of an asymmetric air-gap structure in 3-phase Permanent Magnet Brushless DC Motors. To achieve a high efficiency for a 3-phase PM BLDC motor, the asymmetric air-gap structure is proposed considering the rotation direction of a motor. Generally, a single-phase BLDC motor is applied asymmetric air-gap structure for starting. This is because the asymmetric air-gap structure causes reluctance variation so the motor can utilize reluctance torque toward a rotation direction. In this paper, the asymmetric air-gap is applied to 3-phase BLDC SPM motor so it utilizes reluctance torque with alignment torque. A proposed model is designed by 2-D FE analysis and the results are verified by experimental test.