• 제목/요약/키워드: motion error

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능동제어모세관을 이용한 초정밀 유정압테이블의 5 자유도 운동 오차 보정 (Compensation of Five DOF Motion Errors in a Ultra Precision Hydrostatic Table Using the Active Controlled Capillaries)

  • 박천홍;오윤진;이후상;이득우
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2005년도 춘계학술대회 논문집
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    • pp.769-772
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    • 2005
  • Five DOF motion errors of a hydrostatic bearing table driven by the coreless type linear motor were compensated utilizing the active controlled capillaries in this study. Horizontal linear motion and yaw error were simultaneously compensated using two active controlled capillaries and vertical linear motion, pitch and yaw error were also simultaneously compensated using three active controlled capillaries. By the compensation, horizontal linear motion accuracy and yaw were improved from 0.16 ${\mu}m$ and 1.96 arcsec to 0.02 ${\mu}m$ and 0.03 arcsec. Vertical linear motion accuracy, pitch and roll were also largely improved from 0.18 ${\mu}m$, 2.26 arcsec and 0.14 arcsec upto 0.03 ${\mu}m$, 0.07 arcsec and 0.02 arcsec. The compensated motion errors were within the range of measuring repeatability which was ${\pm}0.02\;{\mu}m$ in the linear motion and ${\pm}0.05$ arcsec in the angular motion. From these results, it is found that the motion error compensation method utilizing the active controlled capillaries are very effective to improve the five motion accuracies of the hydrostatic bearing tables.

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Motion Field Estimation Using U-Disparity Map in Vehicle Environment

  • Seo, Seung-Woo;Lee, Gyu-Cheol;Yoo, Ji-Sang
    • Journal of Electrical Engineering and Technology
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    • 제12권1호
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    • pp.428-435
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    • 2017
  • In this paper, we propose a novel motion field estimation algorithm for which a U-disparity map and forward-and-backward error removal are applied in a vehicular environment. Generally, a motion exists in an image obtained by a camera attached to a vehicle by vehicle movement; however, the obtained motion vector is inaccurate because of the surrounding environmental factors such as the illumination changes and vehicles shaking. It is, therefore, difficult to extract an accurate motion vector, especially on the road surface, due to the similarity of the adjacent-pixel values; therefore, the proposed algorithm first removes the road surface region in the obtained image by using a U-disparity map, and uses then the optical flow that represents the motion vector of the object in the remaining part of the image. The algorithm also uses a forward-backward error-removal technique to improve the motion-vector accuracy and a vehicle's movement is predicted through the application of the RANSAC (RANdom SAmple Consensus) to the previously obtained motion vectors, resulting in the generation of a motion field. Through experiment results, we show that the performance of the proposed algorithm is superior to that of an existing algorithm.

유정압테이블의 정밀도향상을 위한 수정가공 알고리즘 (Corrective Machining Algorithm for Improving the Motion Accuracy of Hydrostatic Table)

  • 박천홍;이찬흥;이후상
    • 한국정밀공학회지
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    • 제19권6호
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    • pp.62-69
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    • 2002
  • For improving the motion accuracy of hydrostatic table, corrective machining algorithm is proposed in this paper. The algorithm consists of three main processes. reverse analysis is performed firstly to estimate rail profile from measured linear and angular motion error, in the algorithm. For the next step, corrective machining information is decided as referring to the estimating rail profile. Finally, motion errors on correctively machined rail are analized by using motion error analysis method proposed in the previous paper. These processes can be iterated until the analized motion errors are satisfied with target accuracy. In order to verify the validity of the algorithm theoretically, motion errors by the estimated rail, after corrective machining, are compared with motion errors by true rail assumed as the measured value. Estimated motion errors show good agreement with assumed values, and it is confirmed that the algorithm is effective to acquire the corrective machining information to improve the accuracy of hydrostatic table.

움직임 보상 프레임 율 변환 기법을 위한 움직임 보상 보간 프레임의 보간 오류 은닉 기법 (Interpolation Error Concealment Method of Motion Compensated Interpolated Frame for Motion Compensated Frame Rate Conversion)

  • 이정훈;한동일
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2008년도 하계종합학술대회
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    • pp.927-928
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    • 2008
  • In this paper, a interpolation error concealment algorithm of motion compensated interpolated frame for motion compensated frame rate conversion to reduce the block artifacts caused by failure of conventional motion estimation based on block matching algorithm is proposed. Experimental results show good performance of the proposed scheme with significant reduction of the block artifacts.

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고정밀 회전체의 불평형 변동에 따른 회전정밀도 영향에 관한 연구 (A Study on the Rotation Accuracy According to Unbalance Variation of High Precision Spindle Unit for Machine Tool)

  • 김상화;김병하;진용규
    • 한국기계가공학회지
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    • 제11권3호
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    • pp.174-181
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    • 2012
  • The spindle unit is a core part in high precision machine tool. Rotation accuracy of spindle unit is needed for high dignity cutting and improving the performance of machine tool. However, there are many factors to effect to rotational error motion(rotation accuracy). This study studied how rotational error motion is variation when unbalance amount is variation. Rotation accuracy of initial spindle unit is decided depending on parts and assembly such as bearing. When it is rotation, vibration and noise is appeared depending on volume of unbalance amount, so it works to decrease unbalance amount. The purpose of the study tests that unbalance amount how much effects to initial rotation condition. The result of the study shows that accuracy of parts and assembly is highly necessary to reach high rotation accuracy and unbalance amount hardly effects to initial rotation accuracy. However, it shorten spindle's life because vibration and noise is increasing by increasing unbalance amount and we can expect situation that rotation accuracy is falling by long time operation.

유정압안내면 운동오차보정용 능동제어모세관의 기본특성 (Basic Characteristics of an Active Controlled Capillary for Compensating the Error Motion of Hydrostatic Guideways)

  • Song, Y.C.;Park, C.H.;Kim, S.T.
    • 한국정밀공학회지
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    • 제14권8호
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    • pp.130-136
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    • 1997
  • For compensating the error motion of hydrostatic guideways, we introduce a way that the clearance of table is actively controlled corresponding to the amount of error with the variable capillary. The structure and the theoretical design method of active controlled capillary using piezo actuator, named ACC, are proposed in this paper. Basic characteristics such as the maximum controllable range, micro step response and available dynamic bandwidth are tested for confirmation of structural suitability of ACC, and these characteristics are also tested on the table mounted with ACC for verifying the availability. The experimental result showed that by the use of ACC, the error motion within 2.7 .mu. m of a hydrostatic guideway can be compensated with the resolution of 2.7nm, 1/100 contollable range, and the frequency bandwidth of 5.5 Hz. From these results, it is confirmed that the ACC is very effective to improve the motion accuracy of high or ultra precision hydrostatic guideways.

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Flexure Analysis of Inertial Navigation Systems

  • Kim, Kwang-Jin;Park, Chan-Gook;Park, Jai-Yong
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2004년도 ICCAS
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    • pp.1958-1961
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    • 2004
  • Ring Laser Gyroscopes used as navigational sensors inherently experience a lock-in region, where very low rotational rates are not measurable. Most RLG manufacturers use a mechanical dither motor that applies a small oscillatory rotational motion larger than this region to resolve this problem. Any input acceleration that bends this dithering axis causes flexure error, which is a noncommutative error that can not be compensated by simply using integrated gyro sensor output. This paper introduces noncommutative error equations that define attitude errors caused by flexure errors. In this paper, flexure error is classified as sensor level error if the sensing axis coincides with the dithering axis and as system level error if the two axes do not coincide. The relationship between gyro output and the rotation vector is introduced and is used to define the coordinate transformation matrix and angular motion. Equations are derived for both sensor level and system level flexure error analysis. These equations show that RLG based INS attitude error caused by flexure is directly proportional to time, amount of input acceleration and the dynamic frequency of the vehicle.

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주변 움직임 벡터의 적응적 선택을 이용한 효율적인 에러은닉 알고리즘 (An Efficient Error Concealment Algorithm using Adaptive Selection of Adjacent Motion Vectors)

  • 이현우;성동수
    • 정보처리학회논문지B
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    • 제11B권6호
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    • pp.661-666
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    • 2004
  • 통신 기술의 발전으로 무선 채널을 이용한 멀티미디어 서비스를 제공하기 위한 방법이 활발히 연구되고 있다. 이에 따라 최근 무선망이나 인터넷과 같이 오류가 많이 발생하는 채널을 통한 비디오의 전송이 급격히 증가하면서 채널 상에서 발생하는 전송에러로 인한 데이터의 손실이 심각한 문제로 대두되고 있으며, 이에 따라 에러 은닉이 주된 관심사로 부각되었다. 에러 은닉 기법은 부가 정보가 필요 없으며, 부호화 기법의 변형 없이 적용이 가능하기 때문에 널리 연구되고 있다. 본 논문에서는, 손실된 블록 주위의 정상블록들 중 움직임 벡터들의 적응적 선택을 이용하여 중간 값을 취한 후, 손실된 블록의 새로운 움직임 벡터로 할당하고, OBMC(Overlapped Block Motion Compensation)을 통해 최종적으로 손실영역을 은닉하게 된다. 이 방법은 연속된 GOB(Group Of Block)의 손실에 있어서 효과적임을 알 수 있었다. 실험 결과 PSNR 성능평가 면에서 제안한 방법의 결과가 기존의 방법들 중 우수한 에러은닉 결과를 내는 MVRI(Motion Vector Rational Interpolation)이나 메디안$.$중첩 에러 은닉 기법에 비해 약 3db정도 향상된 결과를 얻을 수 있었다.

Whole Frame Error Concealment with an Adaptive PU-based Motion Vector Extrapolation for HEVC

  • Kim, Seounghwi;Lee, Dongkyu;Oh, Seoung-Jun
    • IEIE Transactions on Smart Processing and Computing
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    • 제4권1호
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    • pp.16-21
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    • 2015
  • Most video services are transmitted in wireless networks. In a network environment, a packet of video is likely to be lost during transmission. For this reason, numerous error concealment (EC) algorithms have been proposed to combat channel errors. On the other hand, most existing algorithms cannot conceal the whole missing frame effectively. To resolve this problem, this paper proposes a new Adaptive Prediction Unit-based Motion Vector Extrapolation (APMVE) algorithm to restore the entire missing frame encoded by High Efficiency Video Coding (HEVC). In each missing HEVC frame, it uses the prediction unit (PU) information of the previous frame to adaptively decide the size of a basic unit for error concealment and to provide a more accurate estimation for the motion vector in that basic unit than can be achieved by any other conventional method. The simulation results showed that it is highly effective and significantly outperforms other existing frame recovery methods in terms of both objective and subjective quality.

자성보상형 공기정압 저널베어링의 회전운동정밀도 시뮬레이션을 위한 실험적 고찰 (Experimental Investigation for Rotational Error Motion Simulation of Inherently Compensated Aerostatic Journal Bearing)

  • 심종엽;황주호;박천홍
    • 한국정밀공학회지
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    • 제32권2호
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    • pp.135-140
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    • 2015
  • It is an important thing for a designer to simulate and predict the performance of a spindle and a rotary table. In addition to the general performance such as static stiffness, the error motion performance information is beneficial to the designer in many cases. However for an aerostatic bearing the fluid film physical status should be calculated in order to simulate those performances and the calculation time is another obstacle for a simple performance simulation. In this paper the investigation on experiment and simulation is performed in order to find a more effective simulation method for the rotational error motion.