• Title/Summary/Keyword: sensor error

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Study of Magnetic Sensor Harmonic Reduction to Improve Direct Driven Motors Performance Applied to Platform Screen Doors (스크린도어용 다이렉트 드라이브 모터 성능개선을 위한 자기식 센서의 고조파 저감 연구)

  • Kim, Yun-Soo;Lee, Ju
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.11
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    • pp.1645-1650
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    • 2015
  • This paper presents the 3-dimensional electromagnetic field analysis method and correction of sensor distortion that is used by a motor speed sensor. The magnetic sensors are being expanded due to lower price than the other speed sensors such as resolver and encoder. Magnetic sensor generates sine and cosine waves when the motor rotates. However, the sine and cosine signals are distorted due to magnetic noise, which makes the angle error of the sensor, generated near by the Hall element. This paper defines an optimal design variables by using the Taguchi method to minimize output distortion of the magnetic sensor and permanent magnet. To enhance reliability of the magnetic position sensor from sensitivity error, assembly amplitude mismatch and the electrical angle, 3-Dimensional electromagnetic finite element method and correction algorithm errors were performed in due of the magnetic sensor in order to improve the quality of the initial production model.

Investigation of the Thermal Mode-based Thermal Error Prediction for the Multi-heat Sources Model (다중열원모델의 열모드기반 열변위오차 예측)

  • Han, Jun An;Kim, Gyu Ha;Lee, Sun-Kyu
    • Journal of the Korean Society for Precision Engineering
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    • v.30 no.7
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    • pp.754-761
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    • 2013
  • Thermal displacement is an important issue in machine tool systems. During the last several decades, thermal error compensation technology has significantly reduced thermal distortion error; this success has been attributed to the development of a precise, robust thermal error model. A major advantage of using the thermal error model is instant compensation for the control variables during the modeling process. However, successful application of thermal error modeling requires correct determination of the temperature sensor placement. In this paper, a procedure for predicting thermal-mode-based thermal error is introduced. Based on this thermal analysis, temperature sensors were positioned for multiple heat-source models. The performance of the sensors based on thermal-mode error analysis, was compared with conventional methods through simulation and experiments, for the case of a slide table in a transient state. Our results show that for predicting thermal error the proposed thermal model is more accurate than the conventional model.

Error Minimization of Angular Velocity using Encoders and Gyro (엔코더와 자이로를 이용한 각속도 오차 최소화)

  • Kim, Jung-Min;Do, Joo-Cheol;Kim, Sung-Shin
    • Journal of the Korean Institute of Intelligent Systems
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    • v.20 no.6
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    • pp.814-819
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    • 2010
  • This paper is presented to study the error minimization of angular velocity for AGV(autonomous ground vehicle). The error minimization of angular velocity is related to localization technique which is the most important technique for autonomous vehicle. Accelerometer, yaw gyro and electronic compass have been used to measure angular velocity. And methods for error minimization of angular velocity have been actively studied through probabilistic methods and sensor fusion for AGVs. However, those sensors still occure accumulated error by mathematical error, system characters of each sensor, and computational cost are increased greatly when several sensor are used to correct accumulated error. Therefore, this paper studies about error minimization of angular velocity that just uses encoder and gyro. To experiment, we use autonomous vehicle which is made by ourselves. In experimental result, we verified that the localization error of proposed method has even less than the localization errors which we just used encoder and gyro respectively.

Optimal configurations for redundant two-degree of freedom sensor systems (2-자유도 중첩센서의 최적배치)

  • 정도형;이장규;박찬국;박흥원;정태호
    • 제어로봇시스템학회:학술대회논문집
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    • 1991.10a
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    • pp.258-263
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    • 1991
  • Optimal configurations for redundant TDOF (Two Degree Of Freedom) sensor systems are proposed. The determinant of error covariance matrix is used as the performance index, and optimal configurations for 2 TDOF sensor system and 3 TDOF sensor system are evaluated by minimizing the index.

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Development of a Sensor System for Real-Time Posture Measurement of Mobile Robots (이동 로봇의 실시간 자세 추정을 위한 센서 시스템의 개발)

  • 이상룡;권승만
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.9
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    • pp.2191-2204
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    • 1993
  • A sensor system has been developed to measure the posture(position and orientation) of mobile robots working in industrial environments. The proposed sensor system consists of a CCD camera, retro-reflective landmarks, a strobe unit and an image processing board. The proposed hardware system can be built in economic price compared to commercial vision systems. The system has the capability of measuring the posture of mobile robots within 60 msec when a 386 personal computer is used as the host computer. The experimental results demonstrated a remarkable performance of the proposed sensor system in the posture measurement of mobile robots - the average error in position is less than 3 mm and the average error in orientation is less than 1.5.

Implementation of a Mobile Robot Using Landmarks

  • Kim, Sang-Ju;Lee, Jang-Myung
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2003.09a
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    • pp.252-255
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    • 2003
  • In this paper, we suggest the method for a service robot to move safely from an initial position to n goal position in the wide environment like a building. There is a problem using odometry encoder sensor to estimate the position of n mobile robot in the wide environment like a building. Because of the phenomenon of wheel's slipping, a encoder sensor has the accumulated error of n sensor measurement as time. Therefore the error must be compensated with using other sensor. A vision sensor is used to compensate the position of a mobile robot as using the regularly attached light's panel on a building's ceiling. The method to create global path planning for a mobile robot model a building's map as a graph data type. Consequently, we can apply floyd's shortest path algorithm to find the path planning. The effectiveness of the method is verified through simulations and experiments.

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Fabrication and Characteristics of 30 MN Strain Gage Type Force Sensor (30 MN 스트레인 게이지 방식 힘 센서의 제작 및 특성)

  • Kang, D.I.;Song, H.K.;Lee, J.T.
    • Journal of Sensor Science and Technology
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    • v.3 no.2
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    • pp.24-32
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    • 1994
  • A force sensor of 30 MN capacity using build-up technique in which three load cells of 10 MN capacity are arranged in parallel was fabricated. A column spring element was adopted as a shape of a strain gage type load cell. Temperature compensation circuits were used to reduce the error of a load cell. It was estimated that the total error of the fabricated force sensor is less than 0.1 %. The force sensor may be used to calibrate or test material testing machines above 4.5 MN capacity in industries.

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Design of Six-Axis Force/Moment Sensor for Ankle-Rehabilitation Robot (발목재활로봇을 위한 6축 힘/모멘트센서 설계)

  • Kim, Yong-Gook;Kim, Gab-Soon
    • Journal of Institute of Control, Robotics and Systems
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    • v.19 no.4
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    • pp.357-363
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    • 2013
  • Most serious patients who have the paralysis of their ankles can't use of their feet freely. But their ankles can be recovered by an ankle bending rehabilitation exercise and a ankle rotating rehabilitation exercise. Recently, the professional rehabilitation therapeutists are much less than stroke patients in number. Therefore, the ankle-rehabilitation robot should be developed. The developed robot can be dangerous because it can't measure the applied bending force and twisting moment of the patients' ankles. In this paper, the six-axis force/moment sensor for the ankle-rehabilitation robot was specially designed the weight of foot and the applied force to foot in rehabilitation exercise. As a test results, the interference error of the six-axis force/moment sensor was less than 2.51%. It is thought that the sensor can be used to measure the bending force and twisting moment of the patients' ankles in rehabilitation exercise.

Radar, Vision, Lidar Fusion-based Environment Sensor Fault Detection Algorithm for Automated Vehicles (레이더, 비전, 라이더 융합 기반 자율주행 환경 인지 센서 고장 진단)

  • Choi, Seungrhi;Jeong, Yonghwan;Lee, Myungsu;Yi, Kyongsu
    • Journal of Auto-vehicle Safety Association
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    • v.9 no.4
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    • pp.32-37
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    • 2017
  • For automated vehicles, the integrity and fault tolerance of environment perception sensor have been an important issue. This paper presents radar, vision, lidar(laser radar) fusion-based fault detection algorithm for autonomous vehicles. In this paper, characteristics of each sensor are shown. And the error of states of moving targets estimated by each sensor is analyzed to present the method to detect fault of environment sensors by characteristic of this error. Each estimation of moving targets isperformed by EKF/IMM method. To guarantee the reliability of fault detection algorithm of environment sensor, various driving data in several types of road is analyzed.

Design of a Four-axis Force/Moment Sensor for Measuring the Applied Force to Wrist (손목에 가해지는 힘측정을 위한 4축 힘/모멘트센서 설계)

  • Hong, Tae-Kyung;Kim, Gab-Soon
    • Journal of Institute of Control, Robotics and Systems
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    • v.19 no.11
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    • pp.1011-1016
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    • 2013
  • Patients have the paralysis of their wrists, and can't use of their wrists freely. But their wrists can be recovered by wrist-bending rehabilitation exercise. Professional rehabilitation therapeutists exercise the wrists of patients in hospital. But the wrists of patients have not exercised enough for the rehabilitation, because the therapeutists are much less than patients in number. Therefore, the wrist rehabilitation robot should be developed, and it have to measure the applied force to the patients' wrists for their safety. In this paper, the four-axis force/moment sensor was designed for the wrist rehabilitation robot. As a test results, the interference error of the four-axis force/moment sensor was less than 0.91%. It is thought that the sensor can be used to measure the applied force to the patients' wrists.