• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.1025-1028
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• 2002

In this paper, a micro-turning lathe is introduced for micro machining of aluminum rod. To give feed motion, stepwise motion[2] actuators are used instead of the conventional inchworm mechanism. These are consisted of two Piezoelectric ceramics; one is for feeding the slider, and the other is for clamping the slider in the guide way of the body. The guide is V-form. The linearity and positional accuracy of the actuators is good enough far high precision motion. Since the system is more compact than the conventional system using three Piezoelectric ceramics, it is applicable for the micro-machine or MEMS unit. To fabricate the lathe, a small spindle unit with ball bearings of diameter of 10 millimeter is built-up on the top the slider. The motion is feed backed with miniaturized linear encoder attached each axis slider. The diamond tool bite is used for cutting tool. The machining is tried to make small diameter rod. The possible diameter that can be machined in this machine is presented as well as chip formation, surface roughness, and machinability.

• 산업기술연구
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• 제31권A호
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• pp.129-133
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• 2011

In this paper, a surface mounted permanent magnet synchronous motor(SPMSM) drive system for industrial sewing machine was developed. Even through a lowr-esolution encoder is used for a low cost, using a full order observer enables to estimate accurate speed and position. And it also compensates a disturbance torque caused by the belt between a load and a motor. In order to control precisely stop positions of a needle, a speed trajectory is calculated from the acceleration pattern which is obtained from the position reference. The performance of the developed system is verified by experimental results.

• 한국정보통신학회논문지
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• 제25권2호
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• pp.327-329
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• 2021

Underwater acoustic communication channel is influenced by environmental parameters such as multipath, background noise and scattering. Therefore, a transmitted signal is influenced by the sea surface and the sea bottom boundaries, and a received signal shows a delay spread. These factors create a noise in the image and degrade the quality of underwater acoustic communication. To solve these problems, in this paper, we evaluate the performance of an underwater acoustic communication model using a denoising auto-encoder used for unsupervised learning. Noise images generated by the underwater multipath channel were collected and used as training data. Experimental results were analyzed as a PSNR parameter that expressed the noise ratio of the two images.

• 한국정보통신학회논문지
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• 제20권3호
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• pp.639-646
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• 2016

본 연구에서는 특수한 상황(미끄러짐 발생 및 회전관성이 부하로 작용하는 경우)에서의 회전 엔코더 기반 측정방법의 단점을 극복하기 위하여 광 변위센서(ADNS-9500)를 사용한 비접촉식 변위 측정방법을 제안하였다. 정확한 변위 측정을 위해 데이터 수집 보드와 랩뷰를 활용하여 실험적으로 광 변위센서의 성능을 분석하였으며, 반복실험을 통해 실험조건(측정방향, 속도, 가속도, 높이, 표면 재질)에 따른 광 변위센서의 성능특성을 파악하였다. 성능실험 결과, 광 변위센서를 사용하여 정확하게 평면운동을 측정하기 위해서는 광 변위센서와 지면(대상 물체의 표면)과의 높이를 2.4 mm-3.2 mm로 일정하게 유지시켜야 하며, 각각의 축 방향, 속도, 표면 재질을 고려하여 민감도를 수정하여 변위 계산식에 적용해야 하는 것을 확인하였다.

• 한국산학기술학회논문지
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• 제16권7호
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• pp.4405-4410
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• 2015

두 개의 1차원 주기 패턴을 수직으로 중첩시켜 상하층 패턴으로부터 이축 변위 정보를 각각 디코딩할 수 있는 방법을 제안한다. 투명한 상층 패턴 판별은 굴절률차에 기인한 레이저 빔의 디플렉션 검출을 통해 이뤄지고 하층 패턴 판별은 수광 전압 차의 검출를 통해 이뤄진다. 빌드 업 필름 재질의 상층 패턴은 UV 레이저 가공에 의해 미세가공되고 그리고 알루미늄 하층 패턴은 초정밀 머시닝에 의한 트렌치 가공과 불투명 소재 증착 그리고 폴리싱 과정을 통해 제작된다. 10마이크로미터 간격으로 제작된 샘플 패턴과 이를 인코딩할 수 있는 전용 광학계에 의한 변위 측정 방법은 대면적 스테이지에 장착되어 레이저 간섭계를 이용한 측정데이터와 비교하여 검증된다.

• 한국생산제조학회지
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• 제22권1호
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• pp.77-84
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• 2013

In this paper, we review two-dimensional measuring methods referring to target patterns. The patterns consist of two linearly-repeated patterns or is designed repeatedly in two-dimension. The repeated properties are reflectivity, refractivity, air-gapping distance, capacitance, magnetic reluctance, electrical resistance and sloping gradient, etc. However, the optical methods are generally used for high speed processing and density, and their encoding principles are treated here. In case of two-dimensional pattern, as there is not inherently error between single units encoding the pattern except for the metrology frame errors, the end-effector position of an object accompanying the pattern can be measured with respect of the global frame without via error. Therefore, it is regarded as a substitute for laser interferometer with severe environmental constraints and has been applied to the high-accurate planar actuator.

• 한국산업융합학회 논문집
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• 제9권4호
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• pp.277-283
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• 2006

As the products such as HDD, Notebook, PDA, and Mobile Phone become smaller and thinner, the radius of threads as well as holes for assembling those products become smaller, even down to 1mm. To produce such small holes and thread efficiently, multi tapping is highly necessitated. However the multi tapping characteristics is not well known because its complicated cutting mechanism and thus the quality of the produced holes and threads is not well studied yet. In this paper, experiments have been conducted for small-radius threads using M2 and M2.6 and M3 cold forming tap to investigate multi tapping process using several useful signal such as torque and Z-axis encoder pulse. The surface and profile of the machined threads have been magnified and observed through a SEM.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.566-569
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• 2001

Hot Plate is the major unit that it used to remove damp of wafer surface, to strength adhesion of photoresist(PR) and to bake coated PR in FAB process of semiconductor. It is necessary to guarantee the performance of Hot Plate(HP). Therefore, in this study designed and developed the reliability system of HP to measure and estimated thermal uniformity and flatness in temperature setting amplitude $0~250^{\circ}C$. We developed the techniques that measures and analyzes thermal uniformity using infrared thermal vision, and compensates measuring error of flatness using laser displacement sensor. For measuring flatness, we specially makes the measurement stage of 3 axes which adopts the precision encoder. The allowable error of measuring technique is less than thermal uniformity, $\pm 0.1^{\circ}C$ and flatness, $\pm 1mm$. It is expected that the developed system can measure from $\Phi$210(wafer 8") to $\Phi$356(wafer 12") and also can be used in performance test of the Cool Plate and industrial heater, etc.

• 한국군사과학기술학회지
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• 제20권2호
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• pp.231-237
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• 2017

The profile of unpaved road is an important issue in the reliability of endurance test. Efforts on measuring 2D road profile and analyzing the severity have been continued in the study of performing reliable endurance test evaluations through reflecting the results of such measurement and analysis. However, 2D road profile has limitation in measuring the profile in the road width direction because data is obtained along the trailer wheel track. Therefore, in order to measure 3-dimensional shape of road surface and construct severity DB of 3D road profile, Changwon Proving Ground(CPG) of Agency for Defense Development(ADD) developed 3D profilometer which is composed of laser scanner, IMU, GPS, encoder and so on. This paper focuses on the analysis of unpaved road severity using 3D road profile for army operation roads. This results will be used to manage test courses severity of CPG.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.1019-1022
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• 2002

Pipe-cutting machines have been used in many fields. Recently, an automatic pipe-cutting machine that uses magnet has born developed. In this paper, a magnetic-type automatic pipe-cutting machine that attaches itself and performs unmanned cutting process is proposed. It is designed that there is a room at the bottom of its body to contain a magnet. And it uses magnetic force between the magnet and the pipe surface to prevent slip and to attach the machine to the pipe against gravity. Also the magnetic force is adjustable by changing the gap between the magnet and the pipe. This machine is, however, necessary to control cutting velocity for the elevation of work efficiency and the adjustable faculties. During pipe cutting process, the gravity acting on the pipe-cutting machine widely varies. That is, the cutting machine gets fast when moving from the top to the bottom of the pipe and slow when moving from the bottom to the top. Actually the system is kind of a non-linear system where the gravity is function of climbing angle of the cutting machine along the pipe. Especially jerking motion is critical. Therefore, authors design the non-linear controller that estimates the current position of the machine along the pipe and compensates the effect of gravity in this paper. It receives the feed back signal from the encoder.