• The Transactions of the Korean Institute of Power Electronics
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• v.2 no.3
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• pp.37-43
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• 1997

Microstepping control of two phase hybrid step motors provides high step resolution as well as smoothness of operation at low speed, and removes most of the resonance phenomena which is undesirable. This paper focuses on the development of a microstepping driver with enhanced performance. The developed microstepping driver can divide one step(l.8 degree) into 128 microsteps and supports current saving mode to remove the thermal problems which results from long time operation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.1
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• pp.8-13
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• 2003

In this paper, suitablility of 1 GHz CISPR limits establishment fur broadcast communication quality protection is examined and the optimum turn step resolution of EUT for spurious measurement of frequency above 1 GHz to increase the accuracy of maximum values extraction is examined. As a result of 500 MHz and 1.7 GHz clock speed personal computer of micro-processor measurement, optimum turn step resolution extracted by National Institution of National Instrument of Standard & Technology(NIST) Koepke method is estimated 40 table positions per polarization in 500 MHz. And in case of 1.7 GHz, step size is 36 table positions. Prediction of turn step size required for fully scan method in gjgahertz measurement will increase measurement accuracy and reduce considerable measurement time as well.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.205-208
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• 1998

영구자석형 하이브리드 스텝모터는 저가이며 개루프 제어 장치와 더불어 기계적인 제어시스템분야에서 광범위하게 이용되어 왔다. 서보모터 기술의 발달에 따라 영구자석형 스템모터는 고토크, 정밀제어의 응용분야에 있어 중요한 위치를 계속 점유하고 있다. 스텝모터는 외란으로서 작용하는 부하의 영향에 대해 안정한 견고성을 가지며, 적당한 속도와 양호한 분해능의 조합으로 신뢰도가 높고, 구조상 단순한 특징을 갖고 있다. 최근 저가의 개루프 위치제어 장치에 2상 스텝모터와 5상 스텝모터 중에서 어느 것이 더 적합한가에 대한 기술적인 주제가 주목할 어느 것이 더 적합한가에 대한 기술적인 주제가 주목할 만한 문제로 대두되고 있다. 이 두 기기의 구조는 거의 유사하며 같은 원리로 동작한다. 본 논문에서는 이 두 기기의 동작이 명백히 비교될 수 있는 기본적인 수준으로 돌아가서 두 모델을 고찰했다.

• The Optical Journal
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• s.109
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• pp.42-43
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• 2007

프로옵틱스(대표.홍미혜/www.prooptics.co.kr)가 최근 Line CCD용 2um 분해능 PCB, LCD 검사 렌즈로 산업자원부 기술표준원으로부터 NEP 신제품인증을 받으며 다시 한번 저력을 과시했다. 광학산업계에서 24년간의 풍부한 연구실적과 현장경험을 바탕으로 축적한 정진호 소장을 구심점으로 한 전문 R&D기업인 프로옵틱스는 '남들이 못하는 고부가가치 제품에 도전한다'는 모토를 가지고 반도체 검사용 광학계 개발에 주력해 왔으며 향후에는 반도체 스텝퍼용 노광장치 및 인공위성 광학계와 같은 최고의 고부가가치 산업용 광학계 제작에 도전하여 세계속의 선도기술업체로 우뚝 서겠다는 목표를 가지고 있다.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.1
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• pp.88-95
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• 2004

Micro stepping method is adopted in order to eliminate effectively the resonant phenomena and to increase the positional resolution. Exist micro-step method by using Sinusoidal waveform, drive circuit is complex by using micro controller and ROM, it have fault on cost Increase. This paper proposed trapezoidal current wave form for simple control circuit and micro stepping method by using a low cost controller. This paper proposed method verify by using CPLD(EPM9320RC208-15) of low cost. This paper make experiment that comparison of exist method and proposed method. This paper obstruct a escape of motor by using high speed detect.

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.295-296
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• 2009

다중 브래그 파장의 안정성 확보하고 제작비용을 줄이기 위하여 본 연구에서는 하나의 위상마스크와 스텝당 0.004도의 분해능을 갖는 탤봇 간섭계(Talbot Interferometer)로 이루어진 홀로그래픽 격자제작장치를 구성하였다. C-밴드와 L-밴드 파장 범위 내의 다중 브래그 파장 특성을 실험적으로 확인하고, 이 방법을 사용하여 서로 다른 파장의 브래그 격자를 센서부로 두고, $1{\times}6$ 광분배기와 결합시켜 화학반응조 내의 액체 온도를 측정하는 시스템을 제작하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.4C
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• pp.430-436
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• 2009

In this paper, we propose and describe our implementation of an automatic control system for the center wavelength of a fiber Bragg grating. The proposed system consists of a Fabry-Perot filter and cantilever structure controlled by a step motor interfacing computer. We consider the change of the center wavelength and the reflective spectrum shape for a given FBG according to the translation distance of the push stick and the cantilever thickness variation. The proposed system can control the center wavelength of a FBG with a resolution of 0.01 nm by applying compression or extension to the FBG. The proposed system has characteristics that keep the desired wavelength of the FBG with a variation of environmental conditions.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.4
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• pp.34-40
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• 2004

In this paper, we have studied the OCT(Optical Coherence Tomography) system which has been advantages of high resolution, 2-D cross-sectional images, low cost and small size configuration. The characteristics of light source determine the resolution and coherence length. The light source has a commercial SLD with a central wavelength of 1,285 ill11, 35.3 nm(FWHM). The optical delay line is necessary to make equal with the optical path length to scattered light or reflected light from a sample. In order to make equal the optical path length, the stage that is attached to a reference mirror is controled by a step motor. And the interferometer is configured with the Michelson interferometer by using a single mode fiber, and the scanner can be focused on the sample by using a reference ann Also, the 2-dimension cross-sectional images were measured with scanning the transverse direction of the sample by using a step motor. After detecting the internal signal of lateral direction, a scanner is moved to obtain the cross-sectional image of 2-dimension by using step motor. A photodiode, which has high detection sensitivity and excellent noise characteristics has been used. The detected small signal has a noise and interference. After filtering and amplifying the signal, the output signal is demodulated the waveform And then, a cross-sectional image is seen through converting this signal into a digitalized signal by using an AID converter. The resolution of the sample is about 30${\mu}{\textrm}{m}$, which corresponds to the theoretical resolution. Also, the cross-sectional images of onion cells were measured in real time scheme.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.5
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• pp.590-597
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• 1985

A recursive geometric adaptive control method to compensate for machining straightness error in the finished surface due to tool deflection and guideway error generated by end milling process is developed. The relationship between the tool deflection and the feedrate is modeled by a modified Taylor's tool life equation. Without a priori knowledge on the variations off cutting parameters, time varying parameters are then estimated by an exponentially windowed recursive least squares method with only post-process measurements of the straightness error. The location error is controlled by shifting the milling bed in the direction perpendicular to the finished surface and adding a certain amount of feedrate with respect to the tool deflection model before cutting. The waviness error is compensated by adjusting the feedrate during machining. Experimental results show that location error is controlled within a range of fixturing error of the bed on the guideway and that about 60% reduction in the waviness error can be achieved within a few steps of parameter adaption under wide operating ranges of cutting conditions even if the parameters do not converge to fixed values.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.4
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• pp.340-351
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• 2010

This paper presented compact CW sub-THz imaging system using the terahertz transmitter(Tx) that generates 0.34 THz electromagnetic wave based on electronic device. Using 0.34 THz electromagnetic wave generated by Tx, we measured transmitting terahertz wave magnitude and phase information respectively with terahertz receiver(Rx) based on sub harmonic mixer. This paper measured and compared images of several samples to obtain better imaging results by changing time delay and step distance of scanning stage which affect image resolution. Also, through the imaging measurement of various samples, we were able to assure possibility of application of terahertz wave.