• Title/Summary/Keyword: Position Measurement

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Multisensor System Integrating Optical Tactile and F/T Sensors for Determination of Type and Position of 3D Contact Surface (3차원 접촉면의 인식 및 위치의 결정의 위한 광촉각센서와 역각센서의 다중센서시스템)

  • 한헌수
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.33B no.2
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    • pp.10-19
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    • 1996
  • This paper presents a finger-shaped multisensor system which can measure the tyep and position of a target surface by contactl. The multi-sensor system consists of a sphere-shpaed optical tactile sensor located at the finger tip and a force/torque sensor located at the joint of a finger. The optial tactile sensor determines the type and position of the target surface using the shape and position of the CCD image of the touching area generated by a contact between the sensor and the taget surface. The force/torque sensor also determines the position and surface normal vector by applying the distributionof forces and torques t the contact point to the equations of finger shape. The measurements on the position and surface normal vector at a contact point obtined by two individual sensors are fused using a statistical method. The integrated sensor system has 0.8mm error in position measurement and 1.31$^{\circ}$ error in normal vector measurement. The developed sensor system has many applications, such as autonomous compliance control, automatic grasping and recognition, etc.

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Position Estimation of Free-Ranging AGV Systems Using the Extended Kalman Filter Technique (Extended Kalman Filter방법을 이용한 자유주행 무인 방송차의 위치 평가)

  • Lee, Sang-Ryong
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.38 no.12
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    • pp.971-982
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    • 1989
  • An integrating position estimation algorithm has been developed for the navigation system of a free-ranging AGV system. The navigation system focused in this research work consists of redundant wheel encoders for the relative position measurement and a vision sensor for the absolute position measurement. A maximum likelihood method and an extended Kalman filter are implemented for enhancing the performance of the position estimator. The maximum likelihood estimator processes noisy, redundant wheel encoder measurements and yields efficient estimates for the AGV motion between each sampling interval. The extended Kalman filter fuses inharmonious positional data from the deadreckoner and the vision sensor and computes the optimal position estimate. The simulation results show that the proposed position estimator solves a generalized estimation problem for locating the vehicle accurately in space.

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A Reliability Study of Tape and Photography Measurement Techniques for Scapular Position (줄자 및 사진촬영 측정을 이용한 어깨뼈 벌림 측정에 대한 신뢰도 연구)

  • Kim, Moon-Hwan;Yun, Sung-Joon;Ha, Sung-Min
    • Physical Therapy Korea
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    • v.20 no.3
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    • pp.74-80
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    • 2013
  • The purpose of this study was to determine the reliability of distance measurements from the medial border of the scapula to the spinous process of the thoracic vertebrae when obtained using tape and photography measurements. The study included 20 healthy subjects (10 males, 10 females); for a total of 40 scapula measurements. The distance measurements made using tape or photography methods were conducted with the subject in a standing position. Repeated tape and photography measurements were conducted in two sessions on different days by two examiners to assess the inter-rater and intra-rater reliability of the two methods. The reliability of scapular distance measured using tape and photography methods was tested using intraclass correlation coefficients (ICC(3,1)) and the standard error of measurement (SEM). The inter-rater reliability of the tape measurement method was excellent (ICC=.77) and the intra-rater reliability was fair to good (ICC=.74). The inter-rater and intra-rater reliabilities of the photography measurement method were excellent (ICC=.76 and .76 respectively). Our results suggest that photography measurement is an objective and qualitative measurement tool for scapular distance measurements.

A GPS/DR Integration Scheme using Carrier Measurements (반송파 정보를 이용한 GPS/DR 통합 방법)

  • Seo, Hung-Seok;Sung, Tae-Kyung;Lee, Sang-Jeong
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.48 no.10
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    • pp.1279-1286
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    • 1999
  • In conventional GPS/DR integration schemes, the GPS position (or pseudo-range) information is used in calibrating DR sensors. In those schemes, however, an inaccurate calibration may degrade the position accuracy when the GPS measurement is not available. This paper presents a new integration scheme where the GPS velocity information is used in calibrating DR sensors. Also proposed is a new error model of DR sensors for calibrating the bias error and the tilt error in dynamic environments. The proposed model makes it possible that the errors of both the DR sensor parameters and the velocity are calibrated using the GPS carrier-based velocity(or the pseudo-range rate) measurement while the DR position error is calibrated using the GPS position measurement. Since the DR sensors are calibrated accurately, the positioning accuracy is drastically improved when the GPS measurements are unavailable.

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Measurement Method for Fine 6-DOF Displacement of Rigid Bodies (강체의 6자유도 미소 변위 측정)

  • Park, Won-Shik;Cho, Hyung-Suck
    • Journal of Institute of Control, Robotics and Systems
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    • v.8 no.3
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    • pp.208-219
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    • 2002
  • A novel measurement method to obtain the 6-DOF motions of arbitrary rigid bodies is proposed in this paper. The method adopts a specially fabricated mirror called 3-facet mirror, which looks like a triangular pyramid haying an equilateral cross-sectional shape. The mirror is mounted on the objects to be measured, illuminated by a laser beam having circular profile, and reflects the laser beam in three different directions. Three PSDs(position sensitive detector) detect the three beams reflected by the mirror, respectively. From the signals of the PSDs, we can calculate the 3-dimensional position and orientation of the 3-facet mirror, and thus enabling us to determine the 3-dimensional position and orientation of the objects. In this paper, we model the relationship between the 3-dimensional position and orientation of an object in motion and the outputs of three PSDs. A series of experiments are performed to demonstrate the effectiveness and accuracy of the proposed method. The experimental results show that the proposed sensing system can be an effective means of obtaining 3-dimensional position and orientation of arbitrary objects and provide resonable measurement accuracy.

Design of Precision Position Measuring System using Laser Interferometry (광간섭법을 이용한 정밀 위치측정 시스템 설계)

  • 김진상;정성종
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.04a
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    • pp.145-149
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    • 1997
  • A laser mesurement system, a modified Michelson interferometer,which can accurately measure high speed length and position of servomechanisms by detecting a phase shift in the measurement beam using an optical interference was developed. A frequency stabilized laser source and a 20 fold frequency interpolation and digitizing circuit were applied to the system. The refractive index of the ambient air was calibrated through the Edlen's formula. The system achieved a resolution of .lambda./40,16nm, a maximum allowable measurement speed of 600 mm/sec, and a length measurement range of 1500mm. Performance of the system was evaluated on the machining center in short and long length measurements

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Automatic Landing System using a Trajectory of Laser Beam (레이저 빔 궤적을 이용한 강인한 랜딩 시스템)

  • Hwang, Jin-Ah;Nam, Gi-Gun;Lee, Jang-Myung
    • Proceedings of the KIEE Conference
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    • 2006.04a
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    • pp.339-341
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    • 2006
  • This paper proposes a method of container position measurement using automatic landing system that is estimated by a laser range finder. In the most of container position measurement methods, CCD cameras or laser scanners have been used to get the source data. However those sensors are not only weak for disturbances, for examples, the light, fog, and rain, but also the system cost is high. When the spreader arrives the goal position, it is still swung by inertia or by wind effect. In this paper, the spreader swung data have been used to find the container position. The laser range finder is equipped in the front side of spreader. It can measure distance and relative position between spreader and container. This laser range finder can be rotated as desired by a motor. And a tilt sensor is equipped on the spreader to measure spreader sway. We estimate the relative position information between the spreader and a container using the laser range finder and tilt sensor through the geometrical analysis.

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Fast Estimation of Three-dimensional Spatial Light Intensity Distribution at the User Position of an Autostereoscopic 3D Display by Combining the Data of Two-dimensional Spatial Light Intensity Distributions

  • Hyungki Hong
    • Current Optics and Photonics
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    • v.8 no.3
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    • pp.307-312
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    • 2024
  • Measuring the three-dimensional (3D) spatial light intensity distribution of an autostereoscopic multiview 3D display at the user position is time-consuming, as luminance has to be measured at different positions around the user position. This study investigates a method to quickly estimate the 3D distribution at the user position. For this purpose, a measurement setup using a white semitransparent diffusing screen or a two-dimensional (2D) spatial sensor was devised to measure the 2D light intensity distribution at the user position. Furthermore, the 3D spatial light intensity distribution at the user position was estimated from these 2D distributions at different viewing distances. From the estimated 3D distribution, the characteristics of autostereoscopic 3D display performance can be derived and the candidate positions for further accurate measurement can be quickly determined.

Development of Two Dimensional Position Measuring Device for Floating Structure Using an Image Processing Method (이미지 프로세싱을 이용한 부유구조물의 2차원 위치 계측장치 개발)

  • 지명석;김성근;김상봉
    • Journal of Ocean Engineering and Technology
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    • v.8 no.2
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    • pp.166-172
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    • 1994
  • This paper presents an image processing method for two dimensional position measurement of a floating structure. This method is based on image processing technique using concept of window and threshold processing to track the target object. The experimental results for position measurement of the target object in two dimensional water tank demonstrate the validity of this method.

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Contact-Type Ball Tracking Sensor Robust to Impulsive Measurement Noises for Low-cost Ball-and-beam Systems (임펄스 측정잡음에 강인한 저가형 볼앤빔 시스템의 접촉식 볼 추적센서 개발)

  • Jang, Joo Young;Lee, Jaseung;Yoon, Hansol;Ra, Won-Sang
    • Journal of Institute of Control, Robotics and Systems
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    • v.20 no.11
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    • pp.1136-1141
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    • 2014
  • This paper proposes a new contact type ball tracking sensor to improve the control performance of a low cost ball-and-beam system. It is well-known that the impulsive measurement noise contained in ball position measurement is one of the factors which severely degrades the ball-and-beam control performance. The impulsive ball position measurement noises often appear under the sporadical ball floating on the beam. This fact motivates us to devise a simple analog preprocessing circuit to determine whether the ball loses the contact or not. Once the abnormal ball position measurement is detected, the design problem of the ball tracking sensor can be cast into the typical state estimation problem with missing data. In order to tackle the real-time implementation issue, a steady-state Kalman filter is applied to the problem. Through the experimental results, the usefulness of the proposed scheme is demonstrated.