• Title, Summary, Keyword: 오차보정

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Calibration of a Low Grade MEMS IMU Using a High Performance Reference Sensor (고성능 기준 센서를 이용한 저급 MEMS IMU 오차보정)

  • Chang, Keun-Hyung;Chun, Se-Bum;Sung, Sang-Kyung;Lee, Eun-Sung;Jun, Hyang-Sig;Lee, Young-Jae
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.12 no.10
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    • pp.1822-1829
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    • 2008
  • Calibration of an MEMS inertial measurement unit is very important process for obtaining precise navigation performance. In this paper, one method is proposed to overcome a limitations on cost and efficiency using a relatively higher grade sensor and a rate table. The same dynamic input is applied to both the reference and the target sensors during and after calibration process, then the results are analyzed. The experimental results show that the proposed method is very effective and useful in practice.

An Online Calibration Algorithm for Cellular CDMA Antenna Arrays (Cellular CDMA용 배열 안테나 오차 보정 알고리듬)

  • 석미경;조상우;전주환
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.2C
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    • pp.306-314
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    • 2004
  • Some receiver(and most transmit) beamforming algorithms with an array antenna at a cellular CDMA base stations require accurate internal and external calibrations. The external calibration, which usually needs to be done only once, determines the array manifolds, i.e. the complex response of each antenna as a function of DOA(Directions of Arrival). The internal calibrations are necessary because characteristics of RF/IF circuity of each receiver chain vary differently in response to temperature or humidity changes. We propose an iterative subspace-based calibration algorithm for an asynchronous CDMA-based antenna away in the presence of unknown gain and phase error is presented. We verify the subspace-based calibration algorithms by performing the experiment using measured data. Also, we propose an efficient algorithm using the simulated annealing technique. This algorithm overcomes the problem of the initial guessing in the subspace-based approach.

Algorithm of Thermal Error Compensation for the Line Center - System Interface - (CNC공작기계의 열변형 오차보정 (II) - 알고리즘 및 시스템 인터폐이스 중심 -)

  • 이재종;최대봉;박현구;류길상
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.417-422
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    • 2002
  • One of the major limitations of productivity and quality in metal cutting is the machining accuracy of machine tools. The machining accuracy is affected by geometric errors, thermally-induced errors, and the deterioration of the machine tools. Geometric and thermal errors of machine tools should be measured and compensated to manufacture high quality products. In metal cutting, the machining accuracy is more affected by thermal errors than by geometric errors. In this study, the compensation device and temperature-based algorithm have been implemented on the machining center in order to compensate thermal error of machine tools under the real-time. The thermal errors are predicted using the neural network and multi-regression modeling methods. In order to compensate thermal characteristics under several operating conditions, experiments performed with five gap sensors and manufactured compensation device on the horizontal machining center.

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Compensation of Thermal Errors for the CNC Machine Tools (II) - Analysis of Error Compensation Algorithm for the PC-NC Controller - (CNC 공작기계의 열변형 오차 보정 (II) - PC-NC제어기용 오차보정 알고리즘 분석 -)

  • 이재종;최대봉;박현구
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.214-219
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    • 2001
  • One of the major limitations of productivity and quality in metal cutting is the machining accuracy of machine tools. The machining accuracy is affected by geometric errors, thermally-induced errors, and the deterioration of the machine tools. Geometric and thermal errors of machine tools should be measured and compensated to manufacture high quality products. In metal cutting, the machining accuracy is more affected by thermal errors than by geometric errors. In this study, the compensation device and temperature-based algorithm have been presented in order to compensate thermal error of machine tools under the real-time. The thermal error is modeled by means of angularity errors of a column and thermal drift error of the spindle unit which are measured by the touch probe unit with a star type styluses, a designed spherical ball artifact, and five gap sensors. In order to compensate thermal characteristics under several operating conditions, experiments performed with five gap sensors and manufactured compensation device on the horizontal machining center.

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Design of a 2.5GHz Quadrature LC VCO with an I/Q Mismatch Compensator (I/Q 오차 보정 회로를 갖는 2.5GHz Quadrature LC VCO 설계)

  • Byun, Sang-Jin;Shim, Jae-Hoon
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.48 no.2
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    • pp.35-43
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    • 2011
  • In this paper, an analysis on I/Q mismatch characteristics of a quadrature LC VCO(Voltage controlled oscillator) is presented. Based on this analysis, a new I/Q mismatch compensator is proposed. The proposed I/Q mismatch compensator utilizes an amplitude mismatch detector rather than the conventional phase mismatch detector requiring much more wide frequency bandwidth. To verify the proposed circuit, a 2.5GHz quadrature LC VCO was designed in a $0.18{\mu}m$ CMOS process and tested. Test results show that an amplitude mismatch detector achieves similar I/Q mismatch compensation performance as that of the conventional phase mismatch detector. The I/Q mismatch compensator consumes 0.4mA from 1.8V supply voltage and occupies $0.04mm^2$.

Development of Error Compensation Software, ECS

  • Ji, Tae-Geun;Pak, Soojong;Kim, Geon-Hee;Jeong, Byeongjoon;Kim, Sanghyuk;Lee, Hye-In
    • The Bulletin of The Korean Astronomical Society
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    • v.41 no.2
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    • pp.36.3-37
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    • 2016
  • ECS(Error Compensation Software)는 알루미늄 자유곡면 반사경의 형상정밀도를 향상시키기 위해 개발된 보정가공 소프트웨어이다. DTM(Diamond Turning Machine)을 이용한 가공공정에서 가공오차의 변화를 쉽게 확인하며 형상을 보정할 수 있도록 설계되었다. 보정가공 공정은 (1) 10차 다항식을 이용하여 표면을 설계한 후 DTM에 입력할 가공경로 계산, (2) DTM에 가공경로를 입력하여 가공, (3) 3차원 초정밀 형상측정 장비로 반사경의 가공오차 분석, (4) 가공오차를 보정하여 새로운 10차 다항식 설계, (5) 보정가공경로 계산 후 재가공으로 이루어진다. 그동안의 공정은 다항식의 설계, 가공경로 계산, 반사경의 가공오차 분석을 위해 다수의 프로그램들을 실행해야만 했다. 본 연구에서는 ECS가 알루미늄 자유곡면 반사경 제작을 위한 통합 보정가공 소프트웨어를 제공하여, 사용자가 작업을 효율적으로 수행하기를 기대한다.

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Correction of Accelerogram in Frequency Domain (주파수영역에서의 가속도 기록 보정)

  • Park, Chang Ho;Lee, Dong Guen
    • Journal of The Korean Society of Civil Engineers
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    • v.12 no.4
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    • pp.71-79
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    • 1992
  • In general, the accelerogram of earthquake ground motion or the accelerogram obtained from dynamic tests contain various errors. In these errors of the accelerograms, there are instrumental errors(magnitude and phase distortion) due to the response characteristics of accelerometer and the digitizing error concentrated in low and high frequency components and random errors. Then, these errors may be detrimental to the results of data processing and dynamic analysis. An efficient method which can correct the errors of the accelerogram is proposed in this study. The correction of errors can be accomplished through four steps as followes ; 1) using an interpolation method a data form appropriate to the error correction is prepared, 2) low and high frequency errors of the accelerogram are removed by band-pass filter between prescribed frequency limits, 3) instrumental errors are corrected using dynamic equilibrium equation of the accelerometer, 4) velocity and displacement are obtained by integrating corrected accelerogram. Presently, infinite impulse response(IIR) filter and finite impulse response (FIR) filter are generally used as band-pass filter. In the proposed error correction procedure, the deficiencies of FIR filter and IIR filter are reduced and, using the properties of the differentiation and the integration of Fourier transform, the accuracy of instrument correction and integration is improved.

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Heading Error Compensation and Navigation Control of Mobile Robot using a Magentic Sensor (지자기 센서를 이용한 이동로봇의 Heading 오차 보정과 주행제어)

  • 정지봉;신위재;이상식
    • Proceedings of the Korea Institute of Convergence Signal Processing
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    • pp.117-120
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    • 2000
  • 본 논문은 이동로봇이 주행 중 발생하는 heading 오차를 지자기센서를 이용하여 보정하고 주행을 정확히 제어하는 것에 관한 것이다. 일반적으로 이동로봇의 주행제어는 여러 원인에 의한 부정확성을 내포하고 있다. 예를 들어 바퀴의 부정확한 기계적 정렬, 기어의 헐거워짐, 센서 신호의 잡음과 오차, 바퀴의 미끄러짐, 평탄하지 않는 표면에 의한 제도변동 등이다. 따라서, 이동명령어 수행 시 이동로봇의 heading이 의도된 대로 유지되는지를 측정하는 오차 검출이 필요하며 이를 위한 센서 본 논문에서는 지자기센서를 이용하여 오차를 보정하였다. 실험은 무선 원격 제어되는 이동로봇에 지자기 센서를 부착하여 자계의 영향이 비교적 적은 평탄한 옥외에서 수행하였고, 실험 결과를 통해 지자기 센서를 이용한 이동로봇의 heading 오차 보정과 주행제어효과를 보여주었다.

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Systematic error calibration of 2-axis lateral shearing interferometer (2축 층밀리기 간섭계의 계통오차 보정)

  • 김승우;이혁교
    • Korean Journal of Optics and Photonics
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    • v.13 no.2
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    • pp.98-104
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    • 2002
  • We present a new self-calibration method to remove the systematic error of a 2-axis lateral shearing interferometer that has been specially designed for optical testing of aspheric optics. The method takes multiple measurements by rotating the test optics and extracts the systematic error by fitting the measured wavefronts into the Zernike polynomials. The method works with arbitrary azimuthal angles for test optics rotation, which offers an advantage of correcting the error induced by the non-orthogonality of the two axes of wavefront shearing as well as the error caused by the optical components of the interferometer system itself.