• 제목/요약/키워드: Volumetric Positioning errors

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공작기계의 오차요소 측정을 통한 3차원 위치정밀도 향상 (The enhancement of 3-dimensional positioning accuracy by measuring error factors for CNC machine tools)

  • 손진욱;서석환;정세용;이응석;위현곤
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1994년도 추계학술대회 논문집
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    • pp.260-265
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    • 1994
  • Efforts have been devoted to developing rapid and accurate methods for measuring the errors of machine tools. The method os measurement and calibration of machine tool errors should be general and efficient. The objective of this study is to show in detail the full sequence from the measurement of errors factors to the verification of the positioning accuracy after compensation for the volumetric error. In this paper, we described the steps in measuring the volumetric error parameters, a general error model composed of error parameters, temperature, and the desired position. The validity of the error calibration methods proposed in this paper was tested using a vertical 3-axis CNC machine with a laser interferometer and a ball bar.

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공간오차 측정을 통한 6자유도 병렬기구의 보정 (Calibration of 6-DOF Parallel Mechanism Through the Measurement of Volumetric Error)

  • 오용택;아궁 샴수딘 사라기;김정현;고태조
    • 한국기계가공학회지
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    • 제11권3호
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    • pp.48-54
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    • 2012
  • This paper introduces the kinematic calibration method to improve the positioning accuracy of a parallel mechanism. Since all the actuators in the parallel mechanism are controlled simultaneously toward the target position, the volumetric errors originated from each motion element are too complicated. Therefore, the exact evaluation of the error sources of each motion element and its calibration is very important in terms of volumetric errors. In the calibration processes, the measurement of the errors between commands and trajectories is necessary in advance. To do this, a digitizer was used for the data acquisition in 3 dimensional space rather than arbitrary planar error data. After that, the optimization process that was used for reducing the motion errors were followed. Consequently, Levenberg-Marquart algorithm as well as the error data acquisition method turned out effective for the purpose of the calibration of the parallel mechanism.

회전체의 효과적인 3차원 위치오차 측정방법 (A Useful Technique for Measuring the 3-dimensional Positioning of a Rotating Object)

  • 이응석;위현곤;정주노
    • 대한기계학회논문집A
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    • 제21권6호
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    • pp.918-924
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    • 1997
  • A method for measuring the accuracy of rotating objects was studied. Rotating axis errors are significant; such as the spindle error of a manufacturing machine which results in the surface roughness of machined work pieces. Three capacitance type displacement sensors were used to measure the rotating master ball position. The sensors were mounted to the three orthogonal points on the spindle axis. The measurement data were analyzed and shown for rotating spindle accuracy, not only for average roundness error but also for spindle volumetric positional error during the revolutions. This method is simple and economical for industrial field use with regular inspection of rotating machines using portable equipment. Measuring and analyzing time using this method takes only a couple of hours. This method can also measure microscopic amplitude and 3-dimensional direction of vibrating objects.

OMM 시스템에서 측정방향을 고려한 가공물의 오차평가 (Error Prediction Considering the Measurement Direction in OMM System)

  • 최진필;이상조;권혁동
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2002년도 춘계학술대회 논문집
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    • pp.632-635
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    • 2002
  • In this paper, a general procedure to determine machine tool errors from the on-machine measurement (OMM) data is described. First, a parameterized error model of a machine tool is illustrated by approximating error components as linear function of axis positions, and a modified error model is proposed which includes backlash effects. To determine the unknown model coefficient vectors of the forward and backward error model, an artifact with 8 cutes is made and calibrated on CMM. Then, lower-left and upper-right cube corners are measured with a touch-trigger probe mounted on the machine tool spindle. Measured error data are used to determine the coefficient vectors. The positioning errors in the XY plane at the fixed z position are simulated for the forward and backward error model.

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