• Title/Summary/Keyword: Noncontact Method

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Performance Comparison of the Railway Traction IPM Motors between Concentrated Winding and Distributed Winding

  • Park, Chan-Bae;Lee, Byung-Song;Lee, Hyung-Woo
    • Journal of Electrical Engineering and Technology
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    • v.8 no.1
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    • pp.118-123
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    • 2013
  • This paper presents performance comparison between concentrated winding and distributed winding of IPMSM (Interior Permanent Magnet Synchronous Motors) which is recently used for light-weight railway applications. Motors are designed on various schemes and analyzed by using FEM (Finite Element Method) instead of EMCNM (Equivalent Magnetic Circuit Network Method) in order to take into account saturation and non-linear magnetic property. The overall performance such as torque, torque ripple, losses, demagnetization, efficiency, power density and so on are investigated in detail at the rated and maximum operating speed. The results of the analysis found that both concentrated and distributed winding IPMSMs are promising candidates for high power railway traction motor.

Measurement of Ultrasonic Nonlinear Parameter by Using Non-Contact Ultrasonic Receiver (비접촉식 초음파 수신기를 이용한 초음파 비선형성 측정)

  • Kim, Jongbeom;Jhang, Kyoung-Young
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.10
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    • pp.1133-1137
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    • 2014
  • The ultrasonic nonlinear parameter ${\beta}$ is generally known as an effective parameter for evaluating material degradation. Thus far, most research has been conducted using a contact method. However, since measurement by this contact method is affected by the contact conditions between the transducer and the specimen, additional devices are required to maintain the contact conditions stable during the measurement. To avoid this inconvenience, this paper proposes a noncontact method. In this study, only the receiver was replaced with a noncontact receiver, and then, the ultrasonic nonlinear parameters measured by the newly developed noncontact receiver were compared with those measured by the contact receiver. Results obtained using both these receivers for heat-treated aluminum alloy specimens showed good agreement. From this result, we can confirm that the ultrasonic nonlinear parameter ${\beta}$ can be measured using the proposed noncontact ultrasonic method.

A New Method of Noncontact Measurement for 3D Microtopography in Semiconductor Wafer Implementing a New Optical Probe based on the Precision Defocus Measurement (비초점 정밀 계측 방식에 의한 새로운 광학 프로브를 이용한 반도체 웨이퍼의 삼차원 미소형상 측정 기술)

  • 박희재;안우정
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.1
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    • pp.129-137
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    • 2000
  • In this paper, a new method of noncontact measurement has been developed for a 3 dimensional topography in semiconductor wafer, implementing a new optical probe based on the precision defocus measurement. The developed technique consists of the new optical probe, precision stages, and the measurement/control system. The basic principle of the technique is to use the reflected slit beam from the specimen surface, and to measure the deviation of the specimen surface. The defocusing distance can be measured by the reflected slit beam, where the defocused image is measured by the proposed optical probe, giving very high resolution. The distance measuring formula has been proposed for the developed probe, using the laws of geometric optics. The precision calibration technique has been applied, giving about 10 nanometer resolution and 72 nanometer of four sigma uncertainty. In order to quantitize the micro pattern in the specimen surface, some efficient analysis algorithms have been developed to analyse the 3D topography pattern and some parameters of the surface. The developed system has been successfully applied to measure the wafer surface, demonstrating the line scanning feature and excellent 3 dimensional measurement capability.

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FE Deformation Analysis of Noncontact Dry Gas Seal (비 접촉 드라이 가스 시일의 변형에 관한 연구)

  • Huh, You-Jung;Lee, Jae-Hwan;Lee, An-Sung
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2003.10a
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    • pp.41-46
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    • 2003
  • In this paper, two different methods are developed to be used for the design of noncontact dry gas seal which is used to prevent gas leakage of high speed rotating shaft-housing machineries. First method is using FEA to compute the deformation of seal face and the other is using Influence Coefficient Method in order to save computation of FEA. In both cases, heat load and mechanical loads are applied such as heat generation, bulk temperature and nodal force, bulk pressure, centrifugal force, respectively. ICM method is verified correct and effective and both methods give reliable and useful deformation results for the design of mechanical seals.

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Method of the Semi-Automation Camera Calibration for Noncontact Measure of Badly Illumination (불균등 조명에서 비접촉 계측을 위한 반자동 카메라 교정 방법)

  • Kim, Jeong-Hyun;Kim, Min-Seong;Kang, Dong-Joong;Lho, Tae-Jung
    • Proceedings of the IEEK Conference
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    • 2006.06a
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    • pp.281-282
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    • 2006
  • This paper proposed a method of the camera calibration for noncontact measure of badly illumination. The method with a semi-automation camera calibration, The user designates minimum 4 points in calibration pattern. The Perspective transformation predicts the remaining point calibration pattern. It uses at input value of the Tsai and it searches a better point, When being smaller allowable error than until, it repeats and it puts out a good calibration result.

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Local damage detection of a fan blade under ambient excitation by three-dimensional digital image correlation

  • Hu, Yujia;Sun, Xi;Zhu, Weidong;Li, Haolin
    • Smart Structures and Systems
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    • v.24 no.5
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    • pp.597-606
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    • 2019
  • Damage detection based on dynamic characteristics of a structure is one of important roles in structural damage identification. It is difficult to detect local structural damage using traditional dynamic experimental methods due to a limited number of sensors used in an experiment. In this work, a non-contact test stand of fan blades is established, and a full-field noncontact test method, combined with three-dimensional digital image correlation, Bayesian operational modal analysis, and damage indices, is used to detect local damage of a fan blade under ambient excitation without use of baseline information before structural damage. The methodology is applied to detect invisible local damage on the fan blade. Such a method has a seemingly high potential as an alternative to detect local damage of blades with complex high-precision surfaces under extreme working conditions because it is a noncontact test method and can be used under ambient excitation without human participation.

In-process Detection of Surface Roughness and Waviness Using Laser Beam (레이저빔을 이용한 표면거칠기 및 파상도의 in-process 검출)

  • 김희남
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1997.10a
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    • pp.254-259
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    • 1997
  • The measurement of surface roughness and waviness by means of noncontact method is an important area to be developed for GAC(Geometrical Adaptive Control) system. This paper deal with the design of noncontact in-process measurement system which measures the surface roughness and waviness during cylindrical grinding. This measuring system is simple and the apparatus proposed is composed of a laser unit, photodetector and optical system. During operation, the surface of a workpiece is continuously scanned by a laser beam. This method makes it possible to detect the surface roughness and waviness along the feed direction by control the spot diameter of laser beam. The experimental results show that the presence of chattering, loading and glazing can be detected sensitively along the feed directions.

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Noncontact Type Three Dimensional Profile Measurement for CAD Modeling of Sculptured Surface (자유곡면의 CAD 모델링을 위한 비접촉식 삼차원 형상측정)

  • Park, H.G.;Park, Y.B.;Kim, S.W.
    • Journal of the Korean Society for Precision Engineering
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    • v.12 no.1
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    • pp.5-14
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    • 1995
  • An optical measurement method of three dimensional surface profiles which is named the slit beam projection is suggested and practically implemented. This method is intended especially for noncontact and fast digitization of sculptured surfaces for CAD modeling and die manufacturing. Its basic principles are based on geometric optics. Deatiled optical principles and an sub-pixel image processing technique to enhance the measuring resolutions are described in this study. The measuring performances of the slit beam projection are presented and discussed to demonstrate that an actual measuring accuracy of below .+-. 0.2mm can be achived over the whole measuring range(500mm*300mm*200mm)

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A Study on the Detection of Surface Acoustic Waves by Noncontact Method (비접촉 방법에 의한 표면탄성파의 검출)

  • You, I.H.;Yoon, J.S.;Kim, D.I.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.10 no.2
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    • pp.56-62
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    • 1990
  • Surface Acoustic Waves(SAW) are generated on silicon wafer and $YZ-LiTaO_3$ substrate and are detected by noncontact method. As wave sources two kinds of transducers are used : the wedge-type of 20.0 MHz and fabricated Interdigital Transducer(IDT) of 20.8 MHz. SAW are modulated by the optical chopper frequency and are syncronized with a laser beam. In signal processing, intensity variations of light due to the intensity of SAW are analyzed using lock- in amplifier. From the results, corresponding to the applied input power, the intensity variations of a deflected light by corrugations on the substrates are increased and saturation phenomenon is observed.

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Development of Tomograph Technique for Evaluating Thickness Reduction using Noncontact Ultrasonic Sensor Network (두께감육 평가를 위한 비접촉식 초음파 센서 네트워크를 이용한 토모그래프 기술 개발)

  • Lee, J.M.;Kim, Y.K.;Park, I.K.
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.23 no.1
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    • pp.27-31
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    • 2014
  • This paper describes a tomographic imaging technique for evaluating the thickness reduction of a plate-like structure using a noncontact sensor network based on an electromagnetic acoustic transducer that generates shear horizontal plate waves. Because this technique is based on the effect of mode cutoff and time of flight of guided waves caused by a change in thickness, the tomographic image provides information on the presence of defects in the structure. To verify the performance of the method, artificial defects with various thickness reduction ratios were machined in an aluminum plate, and the tomographic imaging results are reported. The results show that the generated tomographic image displays the thickness reductions and can identify their locations. Therefore, the proposed technique has good potential as a tool for health monitoring of the integrity of plate-like structures.