• Title/Summary/Keyword: Motion errors

검색결과 627건 처리시간 0.028초

Analytics of PIV Measurement and Its Application for Higher Performances

  • NISHIO Shigeru;SUGII Yasuhiko
    • 한국가시화정보학회:학술대회논문집
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    • 한국가시화정보학회 2001년도 Proceedings of 2001 Korea-Japan Joint Seminar on Particle Image Velocimetry
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    • pp.62-74
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    • 2001
  • Present paper describes the principles of PIV measurement approaching from the analytical view, which enables to explain the general form of principles covering all the PIV measurement, and that gives theoretical basis for its higher measurement performances. The explanation of the measurement principles started from the definition of governing equation in differential form as same as the gradient method, and the integral along the particle path line was executed to show the principle of the correlation method with same basis. The integral processes clearly shows the analytical reason why the correlation peak gives the terminal point of path line, and how the effects of deformation and rotation of fluid appears in the correlation map. These results have no differences from our experiences and understandings of the conventional PIV measurement definition in final form. However, the analytical approach enable to understand those facts a priori, and it makes easy to achieve the innovative higher performances of measurement. Analytical explanation clearly shows the behavior of the residual errors caused by the fluid motion, and it enables to analyze the measurement uncertainty theoretically.

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벨트 구동 시스템에서의 실시간 반복제어 응용 (Application to Real Time Repetitive Control in Belt Drive Systems)

  • 유영순
    • 제어로봇시스템학회논문지
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    • 제4권4호
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    • pp.420-426
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    • 1998
  • It is the purpose of this paper to make a preliminary study on the use of repetitive control to improve velocity accuracy by eliminating repetitive disturbances caused by machining inaccuracies of the axis of rotation location. If the control system can be intelligent enough to compensate for such machining errors, then one may be able to improve the accuracy of the velocity control, or alternatively, one may maintain the same accuracy and relax the machining tolerances required. This could decrease cost significantly. Experiments are performed testing repetitive control methods on a constant speed rolling operation testbed. The experimental results show very substantial decreases in the tracking error of the system. Spectral data of the output motion are given to demonstrate the attenuation of the disturbance frequencies and harmonics, related to the bandwidth being used. It is seen that the simplest form of repetitive control which is very easily implemented, can produce striking improvement in control system performance in such belt drive rolling operations, and the learning can be accomplished in a short time.

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Off-hooked 트레일러 시스템의 궤적 추종 (Path following of the passive off-hooked trailer system)

  • 이재형;박명국;정우진;김문상;송재복
    • 대한기계학회논문집A
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    • 제27권11호
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    • pp.1831-1839
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    • 2003
  • This paper deals with design and control of passive multiple trailer systems fer practical applications. Due to cost and complexity of trailer mechanism, passive systems are preferred to active systems in this research. The control objective is to minimize trajectory tracking errors of passive multiple trailers. Three types of passive trailer systems-direct-hooked, three-point, and off-hooked- are discussed in this paper. Trajectory tracking performance and stability issues under constant velocity motion are carried out for three types. Various simulations and experiments have been also performed for these three types. It is shown that the proposed off-hooked trailer system produces better tracking performance than the other types.

서브나노급 정밀도의 2 차원 원자현미경 개발 (Two Dimensional Atomic Force Microscope)

  • 이동연;권대갑
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2008년도 추계학술대회A
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    • pp.1778-1783
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    • 2008
  • A compact and two-dimensional atomic force microscope (AFM) using an orthogonal sample scanner, a calibrated homodyne laser interferometer and a commercial AFM head was developed for use in the nanometrology field. The x and y position of the sample with respect to the tip are acquired by using the laser interferometer in the open-loop state, when each z data point of the AFM head is taken. The sample scanner which has a motion amplifying mechanism was designed to move a sample up to $100{\times}100{\mu}m^2$ in orthogonal way, which means less crosstalk between axes. Moreover, the rotational errors between axes are measured to ensure the accuracy of the calibrated AFM within the full scanning range. The conventional homodyne laser interferometer was used to measure the x and y displacements of the sample and compensated via an X-ray interferometer to reduce the nonlinearity of the optical interferometer. The repeatability of the calibrated AFM was measured to sub-nm within a few hundred nm scanning range.

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TEMPORAL ERROR CONCEALMENT ALGORITHM BASED ON ADAPTIVE SEACH RANGE AND MULTI-SIDE BOUNDARY INFORMATION FOR H.264/AVC

  • Kim, Myoung-Hoon;Jung, Soon-Hong;Kang, Beum-Joo;Sull, Sang-Hoon
    • 한국방송∙미디어공학회:학술대회논문집
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    • 한국방송공학회 2009년도 IWAIT
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    • pp.273-277
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    • 2009
  • A compressed video stream is very sensitive to transmission errors that may severely degrade the reconstructed image. Therefore, error resilience is an essential problem in video communications. In this paper, we propose novel temporal error concealment techniques for recovering lost or erroneously received macroblock (MB). To reduce the computational complexity, the proposed method adaptively determines the search range for each lost MB to find best matched block in the previous frame. And the original corrupted MB split into for $8{\times}8$ sub-MBs, and estimates motion vector (MV) of each sub-MB using its boundary information. Then the estimated MVs are utilized to reconstruct the damaged MB. In simulation results, the proposed method shows better performance than conventional methods in both aspects of PSNR.

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Intelligent-CCS Fed Marine-Express Model Train ME03 in Mass-Reduced-Mode

  • Yoshida, Kinjiro;Takami, Hiroshi;Mehara, Hazime
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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    • pp.944-949
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    • 1998
  • This paper presents a new high-performance intelligent controlled current-source (CCS) system which can compensate for modelling errors of armature resistance, leakage and magnetizing inductances and for space harmonic components of speed EMF's. A shuttle-motion simulation is presented in the mass-reduced-mode in which an equivalent vehicle weight is reduced, by 40kg to 7kg. This study provides one of the most important key-tech-nologies in driving practical linear synchronous motor (LSM) Maglev vehicle.

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칼만필터 기반의 도로표지판 추적을 이용한 차량의 횡방향 위치인식 (Lane Positioning in Highways Based on Road-sign Tracking by Kalman Filter)

  • 이재홍;김학일
    • 한국자동차공학회논문집
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    • 제22권3호
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    • pp.50-59
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    • 2014
  • This paper proposes a method of localization of vehicle especially the horizontal position for the purpose of recognizing the driving lane. Through tracking road signs, the relative position between the vehicle and the sign is calculated and the absolute position is obtained using the known information from the regulation for installation. The proposed method uses Kalman filter for road sign tracking and analyzes the motion using the pinhole camera model. In order to classify the road sign, ORB(Oriented fast and Rotated BRIEF) features from the input image and DB are matched. From the absolute position of the vehicle, the driving lane is recognized. The Experiments are performed on videos from the highway driving and the results shows that the proposed method is able to compensate the common GPS localization errors.

LVDT 센서를 이용한 외경 측정 방안에 대한 연구 (A Study on the out-diameter measuring machine by the LVDT sensors)

  • 황정호;노지훈;박기홍
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2006년도 춘계학술대회 논문집
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    • pp.291-292
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    • 2006
  • Currently A demand of high precision workpiece is increasing in industry. At present, roundness measuring machine using Air bearing, coordinate measuring machine that are used from measurement station. but these machines will not be able to apply to In-line process. because of like these machine's price are very expensive and measurement time is long. also, the complexity of conventional roundness measurement method based on fourier transform, it makes difficult to development analysis program. This work present new architecture of a Out-diameter measuring system fur analysis of roundness of product. In this system, the influence of table motion errors is minimize by using two LVDT sensor and knife edge contact tip. We are produce a test machine and make an experimenter on Out-diameter of test bearing. The measurement result compared with roundness measuring machine.

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발사체 직접식 유도법의 유도성능 분석 (Performance Analysis of an Explicit Guidance Scheme for a Launch Vehicle)

  • 최재원
    • 한국정밀공학회지
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    • 제15권6호
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    • pp.97-106
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    • 1998
  • In this Paper, a fuel minimizing closed loop explicit inertial guidance algorithm for orbit injection of a rocket is developed. In the formulation, the fuel burning rate and magnitude of thrust are assumed constant. The motion of rocket is assumed to be subject to the average inverse-square gravity, but negligible effects from atmosphere. The optimum thrust angle to obtain a given velocity vector in the shortest time with minimizing fuel consumption is first determined, and then the additive thrust angle for targeting the final position vector is determined by using Pontryagin's maximum principle. To establish real time processing, many algorithms of onboard guidance software are simplified. The explicit guidance algorithm is simulated on the 2nd-stage flight of the N-1 rocket developed in Japan. The results show that the explicit guidance algorithm works well in the presence of the maximum $\pm$10% initial velocity and altitude errors, and exhibits better performance than the open-loop program guidance. The effects of the guidance cycle time are also examined.

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마이크로 렌즈 연삭기용 주축설계 및 제작에 관한 기초연구 (A Basic Study of High Precision Spindle Design for Micro-Glass Lens Grinding)

  • 김의중;한정훈;박상일;송승훈
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2002년도 추계학술대회 논문집
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    • pp.57-60
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    • 2002
  • The high precision spindle is essential fer mass and low cost production of aspherical glass lens. Especially, in the grinding process of micro glass lens the performance of the spindle determine the machined surface quality. For the aspheric micro glass lens grinding, we design and make a high precision spindle. We use air bearings for high speed and low motion errors of the spindle. And the driving mechanism is an air turbine to remove heat generation. In this study, we make basic performance requirements of the spindle through benchmarking. And we confirm the requirements by basic machining test. We test air consumption, static stiffness, run-out and vibration of the spindle.

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