• Title/Summary/Keyword: motion accuracy measurement

Search Result 192, Processing Time 0.031 seconds

Synthesis of an On-Line 5 Degrees of Freedom Error Measurement System for Translational Motion Rigid Bodies (병진운동 강체의 온라인 5자유도 운동오차 측정시스템 설계 및 해석)

  • 김진상;정성종
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.15 no.5
    • /
    • pp.93-99
    • /
    • 1998
  • Although laser interferometer measurement system has advantages of measurement range and accuracy, it has some disadvantages when measurement of multi degrees of freedom of motion are required. Because the traditional error measurement methods for geometric errors (two straightness and three angular errors) of a slide of machine tools 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 errors of a moving rigid body in real time processes, an on-line error measurement system for simultaneous detection of the five error components of a moving object is required. Using laser alignment technique and some optoelectronic components, an on-line measurement system with 5 degrees of freedom was developed for the geometric error detection in this study Performance verification of the system has been performed on an error generating mechanism. Experimental results show the feasibility of this system for identifying geometric errors of a slide of machine tools.

  • PDF

An alternating motion technique using linear variable differential transformers (선형변이 차동변압기를 이용한 왕복운동 계측기법)

  • Choi, Ju-Ho;Kim, Yoon-Gyeom;Yoo, Jun
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 1996.10b
    • /
    • pp.1380-1383
    • /
    • 1996
  • This paper presents a recoil and counter recoil(R&CR) motion measurement method using linear variable differential transformers(LVDT). The output of a LVDT is obtained from the differential voltage of the 2nd transformers. As a sensor core is attached at the motion body, the output is directly proportional to the core motion. Displacement, velocity and acceleration are measure from the core length. With a comparison between the measurement result and the known value which is obtained by the precision steel tape, the accuracy and the usefulness of the proposed scheme is validated.

  • PDF

Motion Correction in PET/CT Images (PET/CT 영상 움직임 보정)

  • Woo, Sang-Keun;Cheon, Gi-Jeong
    • Nuclear Medicine and Molecular Imaging
    • /
    • v.42 no.2
    • /
    • pp.172-180
    • /
    • 2008
  • PET/CT fused image with anatomical and functional information have improved medical diagnosis and interpretation. This fusion has resulted in more precise localization and characterization of sites of radio-tracer uptake. However, a motion during whole-body imaging has been recognized as a source of image quality degradation and reduced the quantitative accuracy of PET/CT study. The respiratory motion problem is more challenging in combined PET/CT imaging. In combined PET/CT, CT is used to localize tumors and to correct for attenuation in the PET images. An accurate spatial registration of PET and CT image sets is a prerequisite for accurate diagnosis and SUV measurement. Correcting for the spatial mismatch caused by motion represents a particular challenge for the requisite registration accuracy as a result of differences in PET/CT image. This paper provides a brief summary of the materials and methods involved in multiple investigations of the correction for respiratory motion in PET/CT imaging, with the goal of improving image quality and quantitative accuracy.

Measurement of 5 DOF Motion Errors in the Ultra Precision Feed Tables for Error Compensation (오차보정을 위한 초정밀 테이블의 5 자유도 운동오차 측정)

  • 오윤진;박천홍;이득우
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 2004.10a
    • /
    • pp.672-676
    • /
    • 2004
  • In this paper, measuring system of 5 DOF motion errors are proposed using two capacitive type sensor, a straight edge and a laser interfoerometer. Yawing error and pitching error are measured using the laser interferometer, and rolling error is measured by the reversal method using a capacitive type sensor. Linear motion errors of horizontal and vertical direction are measured using the sequential two point method. In this case, influence of angular motion errors is compensated using the previously measured angular motion errors. In the horizontal direction, measuring accuracy is within 0.05 $\mu$m and 0.27 arcsec, and in the vertical direction, it is within 0.15 $\mu$m and 0.5 arcsec. From these results, it is confirmed that the proposed measureing system is very effective to the measurement of 5 DOF motion errors in the ultra precision feed tables.

  • PDF

Effects of Covariance Modeling on Estimation Accuracy in an IMU-based Attitude Estimation Kalman Filter (IMU 기반 자세 추정 칼만필터에서 공분산 모델링이 추정 정확도에 미치는 영향)

  • Choi, Ji Seok;Lee, Jung Keun
    • Journal of Sensor Science and Technology
    • /
    • v.29 no.6
    • /
    • pp.440-446
    • /
    • 2020
  • A well-known difficulty in attitude estimation based on inertial measurement unit (IMU) signals is the occurrence of external acceleration under dynamic motion conditions, as the acceleration significantly degrades the estimation accuracy. Lee et al. (2012) designed a Kalman filter (KF) that could effectively deal with the acceleration issue. Ahmed and Tahir (2017) modified this method by adjusting the acceleration-related covariance matrix because they considered covariance modeling as a pivotal factor in the estimation accuracy. This study investigates the effects of covariance modeling on estimation accuracy in an IMU-based attitude estimation KF. The method proposed by Ahmed and Tahir can be divided into two: one uses the covariance including only diagonal components and the other uses the covariance including both diagonal and off-diagonal components. This paper compares these three methods with respect to the motion condition and the window size, which is required for the methods by Ahmed and Tahir. Experimental results showed that the method proposed by Lee et al. performed the best among the three methods under relatively slow motion conditions, whereas the modified method using the diagonal covariance with a high window size performed the best under relatively fast motion conditions.

Modeling and Measurement of Geometric Errors for Machining Center using On-Machine Measurement System (기상계측 시스템을 이용한 머시닝센터의 기하오차 모델링 및 오차측정)

  • Lee, Jae-Jong;Yang, Min-Yang
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.16 no.2 s.95
    • /
    • pp.201-210
    • /
    • 1999
  • 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 and thermal errors of the machine tools. Therefore, a key requirement for improving te machining accuracy and product quality is to reduce the geometric and thermal errors of machine tools. This study models geometric error for error analysis and develops on-machine measurement system by which the volumetric erors are measured. The geometric error is modeled using form shaping function(FSF) which is defined as the mathematical relationship between form shaping motion of machine tool and machined surface. The constant terms included in the error model are found from the measurement results of on-machine measurement system. The developed on-machine measurement system consists of the spherical ball artifact (SBA), the touch probe unit with a star type stylus, the thermal data logger and the personal computer. Experiments, performed with the developed measurement system, show that the system provides a high measuring accuracy, with repeatability of ${\pm}2{\mu}m$ in X, Y and Z directions.

  • PDF

Development of the Precise Multi-Position Alignment Method using a Pitch Motion (피치운동을 이용한 정밀 다위치 정렬기법 개발)

  • Lee, Jung-Shin
    • Journal of the Korea Institute of Military Science and Technology
    • /
    • v.13 no.4
    • /
    • pp.708-715
    • /
    • 2010
  • In Strapdown Inertial Navigation System, alignment accuracy is the most important factor to determine the performance of navigation. However by an existing self-alignment method, it takes a long time to acquire the alignment accuracy that we want. So, to attain the desired alignment accuracy in as little as $\bigcirc$ minutes, we have developed the precise multi-position alignment method. In this paper, it is proposed a inertial measurement matching transfer alignment method among alignment methods to minimize the alignment error in a short time. It is based on a mixed velocity-DCM matching method be suitable to the operating environment of vertical launching system. The compensation methods to reduce misalign error, especially azimuth angle error incurred by measurement time-delay error and body flexure error are analyzed and evaluated with simulation. This simulation results are finally confirmed by experimentations using FMS(Flight Motion Simulator) in Lab and the integration test to follow the fire control mission.

The Development of Exercise Accuracy Measurement Algorithm Supporting Personal Training's Exercise Amount Improvement

  • Oh, Seung-Taek;Kim, Hyeong-Seok;Lim, Jae-Hyun
    • International journal of advanced smart convergence
    • /
    • v.11 no.4
    • /
    • pp.57-67
    • /
    • 2022
  • The demand for personal training (PT), through which high exercise effects can be achieved within short-term, has recently increased. PT can achieve an exercise amount improvement effect, only if accurate postures are maintained upon performing PT, and exercise with inaccurate postures can cause injuries. However, research is insufficient on exercise amount comparisons and judging exercise accuracy on PT. This study proposes an exercise accuracy measurement algorithm and compares differences in exercise amounts according to exercise postures through experiments using a respiratory gas analyzer. The exercise accuracy measurement algorithm acquires Euler anglesfrom major body parts operated upon exercise through a motion device, based on which the joint angles are calculated. By comparing the calculated joint angles with each reference angle in each exercise step, the status of exercise accuracy is judged. The calculated results of exercise accuracy on squats, lunges, and push-ups showed 0.02% difference in comparison with actually measured results through a goniometer. As a result of the exercise amount comparison experiment according to accurate posture through a respiratory gas analyzer, the exercise amount was higher by 45.19% on average in accurate postures. Through this, it was confirmed that maintaining accurate postures contributes to exercise amount improvement.

Development of a Submicron Order Straightness Measuring Device (서브미크론 진직도 측정장치 개발)

  • 박천홍;정재훈;김수태;이후상
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.17 no.5
    • /
    • pp.124-130
    • /
    • 2000
  • For measuring out the submicron order straightness, a precision measuring device is developed in this paper. The device is constructed with a hydrostatic feed table and a capacitive type sensor which is mounted to the feed table. Straightness is acquired as substracting the motion error of feed table from the measured profile with probe. Motion error of feed table is simultaneously compensated upto 0.120${\mu}{\textrm}{m}$ of linear motion error and 0.20arcsec of angular motion error using the active controlled capillary. Reversal method and strai호t-edge is used fur estimating the measuring accuracy and from the experimental result, it is verified that the device has the measuring accuracy 0.030m. Also, through the practical application on the measurement of ground surface, it is confirmed that the device is very effective to measure the submicron order straightness.

  • PDF

Development of a Modified Exoskeletal Linkage Type Instrument for 3-D Motion Measurement of the Human Knee Joint (무릎관절의 3차원 회전량 측정을 위한 개선된 외골격 링크장치 형태의 측정기구 개발)

  • 김영은;안정호
    • Journal of Biomedical Engineering Research
    • /
    • v.15 no.3
    • /
    • pp.289-294
    • /
    • 1994
  • A new type of electrogoniometer to measure the three dimensional motion of the human knee joint was developed. This instrument is composed of six potentiometers: four arranged for two universal joints, one for pin joint, and one for axial rotation measurement. The voltage change in six potentiometers were collected through A/D converter for acquisition, storage and analysis. With a developed instrument, gait analysis was performed. Compared to earlier developed triaxial type goniometer, new instrument shows its convenience in application and accuracy in measurement.

  • PDF