• Title/Summary/Keyword: Laser Displacement Measurement

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A Study on the Portable Micro Displacement Measurement Using Laser Interferometer (레이저 간섭계를 이용한 이동형 미세 변위 측정에 관한 연구)

  • Choi, K.H.;Yang, H.C.
    • Journal of Power System Engineering
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    • v.10 no.2
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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.

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Comparative Analysis of 3D Laser Scanning and MEP Layout for Measurement of Horizontal Displacement of Structures (구조물 수평변위 계측을 위한 3D Laser scanning과 MEP layout의 비교 분석)

  • Shim, Hak-Bo;Seok, Won-Kyun;Park, Soon-Jeon
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2020.11a
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    • pp.183-183
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    • 2020
  • MEP layout and 3D Laser scanning are widely used equipment for displacement measurement in construction site. In this study, MEP layout and 3D Laser scanning were used to measure the lateral displacement of the same structure, and then the advantages and disadvantages of each were compared and analyzed. In general, it has been shown that MEP layout can save a lot of time compared to 3D Laser scanning. And it was found that the lateral displacement measurement results measured at a distance of 15m were similar to each other.

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Application of Differential GPS for the Displacement Measurement of Self-anchored Suspension Bridge under the Static and Dynamic Loading Cases (DGPS 기법을 이용한 자정식 현수교의 정동적 변위응답 측정 및 분석)

  • Kim, Hyung-Tae;Seo, Ju-Won
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.19 no.11
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    • pp.1126-1132
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    • 2009
  • Bridge structures are designed to support ordinary loadings such as vehicles, wind, temperature and current as well as unexpected loadings like earthquakes and storm. Especially, the displacement of Flexible bridges like an suspension bridge under ordinary loading conditions is necessary to be monitored. In case of long span bridges, there are some difficulties in monitoring the displacement of center of the main span using traditional laser displacement sensors. In this study, the static and dynamic displacement responses due to vehicle loadings were measured by DGPS(differential global positioning system) technique. The displacement response data were compared with data obtained from traditional laser displacement sensors so that the static and dynamic behavior of the bridge under vehicle loadings was examined and the applicability of the displacement response measurement using DGPS technique was verified. The static and dynamic loading test for an self-anchored suspension bridge, So-rok Bridge, was performed using vehicles. The displacement response from DGPS technique and that from laser displacement sensors of the bridge monitoring system were compared. The amplitude of white noise from DGPS based measurement was about 7 mm and that of laser displacement sensor based measurement was about 3 mm. On the other hand, dynamic behavior of the center of main span from DGPS based measurement showed better agreement with influence line of the bridge than that from laser displacement sensors. In addition, there were some irregular and discontinuous variation of data due to the instability of GPS receivers or frequent appearance of GPS satellites. Post-processing via the reference station close to an observation post provided by NGII(National Geographic Information Institute) will be a counter-plan for these defects.

A Study on Laser Interferometer Development for Micro Displacement Measurement in Micro Former (마이크로 성형기에서 미세 변위 측정을 위한 레이저 간섭계 개발에 관한 연구)

  • 최재원;김대현;최경현;이석희;김승수;나경환
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.1195-1198
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    • 2003
  • Micro former has been known as a useful tool for machining micro parts. It makes micro holes automatically with punches, a hole-shape die and material by rotation of crank shaft synchronously. Micro displacement in micro forming affects on the performance of machining because micro forming size is similar with its mechanical displacement. Therefore, the measurement of this micro displacement is essential to be guaranteed to obtain high forming precision in the whole machine as well as its devices. This paper addresses the development of a laser interferometer to measure micro displacement for a micro former. The laser interferometer is able to measure micro displacement during a few micro seconds with non-contact. For the experiment, a laser probe is installed on the optical table with optical devices and a micro displacement generating device. The velocity decoding board is also added to calculate doppler shift frequency directly. Finally simple experiments are conducted to confirm its functional operation.

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Development of a Measurement System for High-Speed Spindle Displacement (고속 스핀들의 변위측정 시스템 개발)

  • Kim, H.G.;Chung, W.J.;Ju, J.H.;Cho, Y.D.
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.17 no.6
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    • pp.8-13
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    • 2008
  • At present many research projects on high-speed spindles are being conducted. These projects require a measurement technique which includes heat expansion, vibration and displacement measurement according to angular velocity. This paper presents the development of a measurement system for high-speed spindle displacement. The measurement system is based on $LabView^{(R)}$ and features the following sensors: optical sensor which reacts to the position of a marker on the spindle and enables two Laser Displacement Sensors(LDS). These Laser Displacement Sensors send their data to a DAQ(Data Acquisition Device). It is important that the delay time caused by the response times of the sensors as well as the sampling rate of the DAQ is considered because the spindle revolves at very high speeds.

A Study of Micro Displacement Measurement of Micro System using the Laser Interferometer (레이저 간섭계를 이용한 마이크로 시스템의 미소변위 측정에 관한 연구)

  • Choi, Kyung-Hyun;Kim, Chang-Jong;Cho, Su-Jeong
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.5 no.2
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    • pp.22-26
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    • 2006
  • This paper addresses the development of a laser interferometer to measure micro displacement for a micro system. The laser interferometer is able to measure micro displacement during a few micro seconds with non-contact. In order to employ the interferometer, the displacement calibration experiment should be required. For the experiment, a laser probe installed on the optical table with optical devices and a micro stage. The velocity decoding board is also added to calculate doppler shift frequency directly. The output signal is processed by LabView. Finally experiments are found out the relation between displacement and output signal.

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Displacement Measurement of an Existing Long Span Steel Box-Girder using TLS(Terrestrial Laser Scanning) Displacement measurement Model (TLS 변위계측모델을 이용한 장스팬 철골 박스형 거더의 변위 계측)

  • Lee, Hong-Mn;Park, Hyo-Seon;Lee, Im-Pyeong;Kwon, Yun-Han
    • 한국방재학회:학술대회논문집
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    • 2007.02a
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    • pp.53-56
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    • 2007
  • It was previously introduced a new displacement measuring technique using terrestrial laser scanning (TLS) that remotely samples the surface of an object using laser pulses and generates the three-dimensional (3D) coordinates of numerous points on the surface. In this paper, for an assessment of the capabilities of the measuring technique about existing structures, the field tests for vertical displacement measurement of an existing long span steel box-girder are experimentally carried out. The performance of the technique is evaluated by comparing the displacements obtained from TLS system and displacements directly measured from linear variable displacement transducer (LVDT).

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Laser pose calibration of ViSP for precise 6-DOF structural displacement monitoring

  • Shin, Jae-Uk;Jeon, Haemin;Choi, Suyoung;Kim, Youngjae;Myung, Hyun
    • Smart Structures and Systems
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    • v.18 no.4
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    • pp.801-818
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    • 2016
  • To estimate structural displacement, a visually servoed paired structured light system (ViSP) was proposed in previous studies. The ViSP is composed of two sides facing each other, each with one or two laser pointers, a 2-DOF manipulator, a camera, and a screen. By calculating the positions of the laser beams projected onto the screens and rotation angles of the manipulators, relative 6-DOF displacement between two sides can be estimated. Although the performance of the system has been verified through various simulations and experimental tests, it has a limitation that the accuracy of the displacement measurement depends on the alignment of the laser pointers. In deriving the kinematic equation of the ViSP, the laser pointers were assumed to be installed perfectly normal to the same side screen. In reality, however, this is very difficult to achieve due to installation errors. In other words, the pose of laser pointers should be calibrated carefully before measuring the displacement. To calibrate the initial pose of the laser pointers, a specially designed jig device is made and employed. Experimental tests have been performed to validate the performance of the proposed calibration method and the results show that the estimated displacement with the initial pose calibration increases the accuracy of the 6-DOF displacement estimation.

Comparative study on displacement measurement sensors for high-speed railroad bridge

  • Cho, Soojin;Lee, Junhwa;Sim, Sung-Han
    • Smart Structures and Systems
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    • v.21 no.5
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    • pp.637-652
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    • 2018
  • This paper presents a comparative study of displacement measurement using four sensors that are being used in the field: they are a ring gauge, a laser Doppler vibrometer (LDV), a vision-based displacement measurement system (VDMS), and an optoelectronic displacement meter (ODM). The comparative study was carried out on a brand-new high-speed railroad bridge designed to produce displacements within a couple of millimeters under the loading of a high-speed train. The tests were carried out on a single-span steel plate girder bridge two times with different train loadings: KTX and HEMU. The measured displacement is compared as raw and further discussion was made on the measurement noise, peak displacement, and frequency response of four sensors. The comparisonsare summarized to show the pros and cons of the used sensors in measuring displacement at a typical high-speed railroad bridge.