• Title/Summary/Keyword: laser measurement

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Three-dimensional vibration measurement algorithm using one laser scanning vibrometer (한대의 LSV 를 이용한 3 차원 진동측정방법)

  • Kim, Dong-Kyu;Song, Ha-Jun;Park, Kyi-Hwan
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2012.04a
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    • pp.935-939
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    • 2012
  • 3D vibration measurement is achieved using one laser scanning vibrometer(LSV) and Laser scanner(LS) by moving the LSV to three arbitrarily locations from the principle that vibration analysis based on the frequency domain is independent of the vibration signal based on time domain. The proposed system has the same effect as using three sets of LSVs. It has an advantage of reducing equipment costs. Analytical approach of obtaining in-plane and out-of-plane vibration of surface is introduced using geometrical relations between three LSV coordinates and vibration measured at three different locations.

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Laser Based Temperature Measurement of Rotating Disk Using Thermocolor (서모컬러를 이용한 회전 디스크의 레이저 온도 측정)

  • Na, Wonhwi;Yoo, JaeChern
    • Journal of Sensor Science and Technology
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    • v.22 no.1
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    • pp.49-53
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    • 2013
  • In this paper, we proposed a laser-based non-contact temperature measuring method for high speed rotating polycarbonate (PC) disk using transparency change of thermocolor. The thermocolor has abilities to change color and transparency due to a change in temperature. The thermocolor is applied on one side of polyvinylidene fluoride (PVDF) membrane. The thermocolor applied membrane is attached to inside of reaction chamber in disk. An optical system consisted of a laser beam radiator and a laser photometer is installed. Laser is irradiated at the bottom side of disk and the transmitted laser beam is detected by the laser photometer at the opposite side of disk. During the disk is rotating, laser is irradiated and detected simultaneously. The laser photometer senses the transmitted laser power and generates voltage as output. The temperature of disk can be detected during the disk is rotating up to 3000 RPM.

Simulation of ND Filter for Terrestrial Laser Scanner (3차원 레이저 스캐너용 ND 필터의 시뮬레이션)

  • Yang, Soo-Hyo;Oh, Dong-Geun;Jeong, Joong-Yeon
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • 2009.04a
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    • pp.65-73
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    • 2009
  • The terrestrial laser scanner measures the signal delay time of electronic circuit in EDM(Electronic Distance Measurement) Module for distance measurement. To measure signal delay time precisely, transmitting laser beam of terrestrial laser scanner is divided optically. Therefore, 10% of the laser beam power is entered into the electronic circuit and the others go out through lens. But, measure of delay time is severe in the laser scanner system that the laser beam power is changed dynamically by reflectance of a object, because characters like gain of electronic circuit involving APD(Avalanche Photo Diode) and so on are changed by incident laser beam. Therefore, we adapt ND(Neutral Density) filter that has grid pattern to the laser scanner system to keep constant the incident laser beam power. In this paper, we propose the simulation program for efficient design of ND filter pattern. Finally, to affirm simulation program, we conduct the experimental test of simulated ND filter that has linearly transmittance change, and we consider the experiment result.

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A Study on Precision Measurement of Rock Joint Using 3D-Laser Scanner (3D-Laser scanner를 이용한 암반 절리의 정밀측정에 관한 연구)

  • 이승호;황영철;김세현;심석래;정태영
    • Explosives and Blasting
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    • v.22 no.3
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    • pp.103-111
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    • 2004
  • The existing methods that can be adopted for measuring joints involve either to use borehole or photogrammetry. Due to restricted space, acquisition of data in limited area, and measurement errors, above methods have limitations acquiring the objective and correct results. To get over defects of existing joint measurement methods, joints have been measured using 3D-Laser scanner with accuracy and efficiency. This research aims to investigate an accuracy and applicabiliy of 3D-Laser scanner for measuring rock slope joints. Measurement of rock slope joints has been executed using 3D-Laser scanner & clinometer and then, results from both methods are compared. Results from both methods indicate that they show nearly equal features for joint distributions and numbers of joint information obtained by 3D-Laser scanner are much more than ones measured using clinomer. Therefore, 3D-Laser scanner turns out to be very effective by the fact that it contributes to reduce investigation costs & periods, objectify data from rock slope joints.

A Study on On-line 5 Degrees of Freedom Error Measurement using Laser Optical System (레이져 광학장치를 이용한 온라인 5 자유도 오차측정에 관한연구)

  • 김진상;정성종
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.375-378
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    • 1995
  • Although laser interferometer measurement system has the advantage of range and accuracy, the traditional error measurement methods for geometric errors(two straightness and three angular errors) of a machine tool measures error components one at a time. It may also create an optical path difference and affect the measurement accuracy. In order to identify and compensate for geometric error of a moving body, an on-line measurement system for simultaneous detection of the five error components of a moving axis is required. An on-line measurement system with 5 degrees of freedom was developed for geometric error detection. Performance verification of the system was performed on an error generating mechanism. Experimental results show the feasibility of this system for identifying geometric errors of a side of machine tool.

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Laser-based Relative Navigation Using GPS Measurements for Spacecraft Formation Flying

  • Lee, Kwangwon;Oh, Hyungjik;Park, Han-Earl;Park, Sang-Young;Park, Chandeok
    • Journal of Astronomy and Space Sciences
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    • v.32 no.4
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    • pp.387-393
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    • 2015
  • This study presents a precise relative navigation algorithm using both laser and Global Positioning System (GPS) measurements in real time. The measurement model of the navigation algorithm between two spacecraft is comprised of relative distances measured by laser instruments and single differences of GPS pseudo-range measurements in spherical coordinates. Based on the measurement model, the Extended Kalman Filter (EKF) is applied to smooth the pseudo-range measurements and to obtain the relative navigation solution. While the navigation algorithm using only laser measurements might become inaccurate because of the limited accuracy of spacecraft attitude estimation when the distance between spacecraft is rather large, the proposed approach is able to provide an accurate solution even in such cases by employing the smoothed GPS pseudo-range measurements. Numerical simulations demonstrate that the errors of the proposed algorithm are reduced by more than about 12% compared to those of an algorithm using only laser measurements, as the accuracy of angular measurements is greater than $0.001^{\circ}$ at relative distances greater than 30 km.

Squareness Estimation for Coordinate Measuring Machine Using the Laser Interferometer Measurement Based on the Face-Diagonal Method (Face-Diagonal 방법 기반의 레이저 간섭계 측정을 이용한 CMM 의 직각도 추정)

  • Lee, Hoon Hee;Lee, Dong Mok;Yang, Seung Han
    • Journal of the Korean Society for Precision Engineering
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    • v.33 no.4
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    • pp.295-301
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    • 2016
  • The out-of-squareness is one of the error sources that affect the positioning accuracy of machine tools and coordinate measuring machines. Laser interferometer is widely used to measure the position and angular errors, and can measure the squareness using an optical square. However, the squareness measurement using the laser interferometer is difficult, as compared to other errors due to complicated optics setup and Abbe's error occurrence. The effect of out-of-squareness mainly appears at the face-diagonal of the movable plane. The diagonal displacements are also affected by the position dependent geometric errors. In this study, the squareness estimation techniques via diagonal displacement measurement using the laser interferometer without an optical square were proposed. For accurate estimation and measurement time reduction, the errors selected from proposed discriminant were measured. Discrepancy between the proposed technique with the laser interferometer (with an optical square) result was $0.6{\mu}rad$.

Enhancement of Tracking Performance of Laser Tracking System for Measuring Position Accuracy of Robots

  • Hwang, Sung-Ho;Choi, Gyeong-Rak;Lee, Ho-Gil;Shon, Woong-Hee;Kim, Jin-Young
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.61.5-61
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    • 2001
  • The laser tracking system(LTS) presents the most promising technique for dynamic position measurement of industrial robots. This system combine the advantage of high accuracy with a contactless measurement technique. It is the measurement system of position in three dimensions using distance data obtained by laser interferometer and real time angle by tracking mirror assembly. After measuring the tracking error of the beam projected on the center of retroreflector in robot end effector, this system tracks the end effector continuously by adjusting tracking mirror angle to minimize this error ...

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A study on the measurement of vibration using Laser Doppler Interferometer (레이저 도플러 간섭계를 이용한 진동 측정에 관한연구)

  • Kim, Chang-Hyun;Kim, Ho-Seong
    • Proceedings of the KIEE Conference
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    • 1996.07c
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    • pp.1738-1740
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    • 1996
  • Laser Doppler Vibrometer using heterodyne method with a 632.8 nm He-Ne laser, has been developed for the measurement of small displacement and velocity. The measurement uses heterodyne method can be made insensitive to undesired vibration effect acting the system and can yield the sign of Doppler shift at the expense of increased complexity. A Bragg cell gives a frequency shift of 40MHz for heterodyne method. Frequency Modulated output is detected by spectrum analyzer.

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