• Title/Summary/Keyword: Estimated Position

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Geodetic Point Positioning using the GPS Csrrier Phase (GPS 반송파 위상을 이용한 측지학적인 절대위치 결정)

  • 강준묵;정용식;최종현
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.14 no.2
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    • pp.181-188
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    • 1996
  • Geodetic Satellite Positioning Techniques (NNSS, Transit, Doppler, VLBI, SLR etc.) still have much difficulty in surveying and necessity of point positions is being amplified in korea. Therefore some research institutes have being investigated point positioning using the GPS. In this study, 1 arranged the theory deal with point positioning using GPS carrier beat phase of dual frequency and estimated corrections of errors that be included in GPS observable. Also, 1 determined point position by the differencing scheme of GPS carrier phase, and analyzed the accuracy of point position. 1 suggested potentiality of geodetic point positioning using GPS carrier phase by comparing result of relative positioning with result of point positioning and analyzing result of network adjustment fixed any point position.

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Near-field Target Localization Using Bottom-mounted Linear Sensor Array in Multipath Environment (다중경로환경에서 바닥고정형 선배열센서를 이용한 근거리표적의 위치추정기법)

  • 이수형;류창수;이균경
    • The Journal of the Acoustical Society of Korea
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    • v.19 no.7
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    • pp.7-14
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    • 2000
  • In this paper, we propose a near-field target localization algorithm using a bottom-mounted linear sensor amy in a multipath environment. In a multipath environment, the conic angles of a target signals through each path are different, and the position of the target can be estimated using these conic angles and the time difference of these signals. We derive equations on the relation of time-difference of signals and conic angles estimates under the far-field assumption, and estimate the position of target by simultaneously solving these equations. For a certain geometry of a target and the sensor array, there exist cases when the conic angles are very close. In such a case, we estimate the position of the target using an additional 1-D search.

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System identification and admittance model-based nanodynamic control of ultra-precision cutting process (다이아몬드 터닝 머시인의 극초정밀 절삭공정에서의 시스템 규명 및 제어)

  • 정상화;김상석;오용훈
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10b
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    • pp.1352-1355
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    • 1996
  • The control of diamond turning is usually achieved through a laser-interferometer feedback of slide position. If the tool post is rigid and the material removal process is relatively static, then such a non-collocated position feedback control scheme may surface. However, as the accuracy requirement gets tighter and desired surface contours become more complex, the need for a direct tool-tip sensing becomes inevitable. The physical constraints of the machining process prohibit any reasonable implementation of a tool-tip motion measurement. It is proposed that the measured force normal to the face of the workpiece can be filtered through an appropriate admittance transfer function to result in the estimated depth of cut. This can be compared to the desired depth of cut to generate the adjustment control action in addition to position feedback control. In this work, the design methodology on the admittance model-based control with a conventional controller is presented. The recursive least-squares algorithm with forgetting factor is proposed to identify the parameters and update the cutting process in real time. The normal cutting forces are measured to identify the cutting dynamics in the real diamond turning process using the precision dynamometer. Based on the parameter estimation of cutting dynamics and the admittance model-based nanodynamic control scheme, simulation results are shown.

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Disturbance Observer based Feedback Linearization Control for Electro-Hydraulic Servo Systems (전기 유압 서보 시스템의 비선형 외란 관측기 기반피드백 선형화 제어)

  • Won, Daehee;Kim, Wonhee;Chung, Chung Choo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.2
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    • pp.297-303
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    • 2015
  • We propose a disturbance observer(DOB) based feedback linearization control to improve position tracking performance in the presence of disturbance. The proposed method consists of a disturbance observer and a feedback linearization controller. The disturbance observer is designed to estimate the load force disturbance in electro-hydraulic systems. An auxiliary state variable is proposed in order to avoid amplification of the measurement noises in the disturbance observer. Using the estimated disturbance enables the Electro-hydraulic servo systems(EHS) dynamics to be changed into feedback linearization from. In order to compensate for the disturbance and to track the desired position, the feedback linearization based controller is proposed. The proposed method has a simple structure which can easily be implemented in practice. As a result, the proposed method improves the position tracking performance in the presence of disturbance. Its performance is validated via simulations.

Admittance Model-Based Nanodynamic Control of Diamond Turnning Machine (어드미턴스 모델을 이용한 다이아몬드 터닝머시인의 극초정밀 제어)

  • 정상화;김상석
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.04a
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    • pp.49-52
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    • 1996
  • The control of diamond turning is usually achieved through a laser-interferometer feedback of slide position. The limitation of this control scheme is that the feedback signal does not account for additional dynamics of the tool post and the material removal process. If the tool post is rigid and the material removal process is relatively static, then such a non-collocated position feedback control scheme may surfice. However, as the accuracy requirement gets tighter and desired surface contours become more complex, the need for a direct tool-tip sensing becomes inevitable. The physical constraints of the machining processprohibit any reasonable implementation of a tool-tip motion measurement. It is proposed that the measured force normalto the face of the workpice can be filterd through an appropriate admittance transfer function to result in the estimated depth of cut. This can be compared to the desired depth of cut to generate the adjustment cotnrol action in addition to position feedback control. In this work, the design methodology on the admittance model-based control with a conventional controller is presented. Based on the empirical data of the cutting dynamics, simulation results are shown.

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A friction compensation scheme based on the on-line estimation with a reduced model (축소 모델을 이용한 마찰력의 마찰력의 온라인 추정 및 보상기법)

  • Choi, Jae-Il;Yang, Sang-Sik
    • Journal of Institute of Control, Robotics and Systems
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    • v.2 no.3
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    • pp.174-180
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    • 1996
  • The friction is one of the nonlinearities to be considered in the precise position control of a system which has electromechanical components. The friction has complicated nonlinear characteristics and depends on the velocity, the position and the time. The conventional fixed friction compensator and the controller based on linear control theory may cause the steady state position error or oscillation. The plant to be controlled in this study is a positioning system with a linear brushless DC motor(LBLDCM). The system behaves like a 4th-order model including the compliance and the friction. In this study, the plant model is simplified to a 2nd-order model to reduce the computation in on- line estimation. Also, to reduce the computation time, only the friction is estimated on-line while the mass and the viscous damping coefficient are fixed to the values obtained from off-line estimation. The validity of the proposed scheme is illustrated with the computer simulation and the experiment where the friction is compensated by using the estimation.

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A Study on the Accuracy of the Loran-C Fix of Korean Chain in Korean Southeast Coast (한국 동남연안에서의 로란 C 한국체인의 측위정도에 관한 연구)

  • 신형일;정세모;김진건;박주삼
    • Journal of the Korean Institute of Navigation
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    • v.20 no.3
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    • pp.1-11
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    • 1996
  • The accuracy for determining fishing ground and for setting fishing gear location, and the repeatability of ship position vary depending on fishing methods. Especially, Loran-C has been served to give fisherman highly accurate ship's position, and a number of fishing vessel are equipped with it's receivers. In this paper, in order to evaluate the accuracy of Loran-C fix of Korean chain in Korean southeast coast, the authors examined and analyzed the data of the receiver of Loran-C(LC 90, Furuno) and GPS(AccNav $Sport^{TM}$, Eagle) measured automatically and continuously for 2 seconds at interval of 5minutes during 2hours from $11^{th}$ to $21^{st}$, July, 1996 at six observed points, that is, Pusan, Wolnae, Pangojin, Chongja, Kampo and Kuryongpo in Korean southeast coast. As the result obtained, Loran-C signals showed little fluctuation with good reprodutibility. Good stability of Loran-C signals was indicated by the small value of the standard deviation 0.064~0.094$\mu\textrm{s}$. Although determination of the observed position could not be completely accurate, the extent of the error was estimated smaller than 0.35 nautical mile.

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Asynchronous Sensor Fusion using Multi-rate Kalman Filter (다중주기 칼만 필터를 이용한 비동기 센서 융합)

  • Son, Young Seop;Kim, Wonhee;Lee, Seung-Hi;Chung, Chung Choo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.11
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    • pp.1551-1558
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    • 2014
  • We propose a multi-rate sensor fusion of vision and radar using Kalman filter to solve problems of asynchronized and multi-rate sampling periods in object vehicle tracking. A model based prediction of object vehicles is performed with a decentralized multi-rate Kalman filter for each sensor (vision and radar sensors.) To obtain the improvement in the performance of position prediction, different weighting is applied to each sensor's predicted object position from the multi-rate Kalman filter. The proposed method can provide estimated position of the object vehicles at every sampling time of ECU. The Mahalanobis distance is used to make correspondence among the measured and predicted objects. Through the experimental results, we validate that the post-processed fusion data give us improved tracking performance. The proposed method obtained two times improvement in the object tracking performance compared to single sensor method (camera or radar sensor) in the view point of roots mean square error.

Rotor Position and Speed Detect Using Resolver Interface (레졸바 인터페이스를 이용한 회전자 위치 및 속도 검출)

  • Kim, Young-Choon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.10
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    • pp.4569-4573
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    • 2011
  • Resolver doesn't have a advantage to price in comparision with encorder. However, resolver is used to the case of detecting a absoluteness position and is used to a fine control in the place of having a stability by mechanic. The position by resolver and the method by speed detecting is applied by observer and have a part of processing analog signal. In this paper, we used the method which output signal of resolver is demodulated by cos and sin waveform and the demodulated analog signal is transmitted to controller. We designed the estimated on the program of a controller and observed the movement on the low speed.

Estimation of Vehicle Position and Orientation on Magnetic Lane Using 3-axis Magnetic Sensor (3축 자기센서를 이용한 자기차선상의 차량위치 및 방향 추정)

  • Ryoo, Young-Jae
    • Journal of Sensor Science and Technology
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    • v.9 no.5
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    • pp.373-379
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    • 2000
  • In this paper, an estimation system of vehicle position and orientation on magnetic lane, which is a parameter of the steering controller for automated lane following is described. To verify that the magnetic dipole model could be applied to a magnetic unit paved in roadway, the analysis of the model is compared with the data of 3-axis magnetic field measured experimentally. The sensor location could be estimated by analysis of the model based on experimental data. For the magnetic lane model merged magnetic unit, the relation of sensor location and magnetic field is acquired experimentally. The proposed estimation of vehicle position and orientation is adopted to automated lane following by computer simulation.

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