• Title/Summary/Keyword: Spherical sensor

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Development of finger-force measuring system with three-axis force sensor for measuring a spherical-object grasping force (3축 힘센서를 이용한 구물체 잡기 손가락 힘측정시스템 개발)

  • Kim, Hyeon-Min;Kim, Gab-Soon
    • Journal of Sensor Science and Technology
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    • v.19 no.3
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    • pp.238-245
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    • 2010
  • Stroke patients can't use their hands because of the paralysis of their fingers. Their fingers are recovered by rehabilitating training, and the rehabilitating extent can be judged by grasping a spherical object. At present, the object used in hospital is only a spherical object, and can't measure the force of fingers. Therefore, doctors judge the rehabilitating extent by touching and watching at their fingers. So, the spherical object measuring system which can measure the force of their fingers should be developed. In this paper, the finger-force measuring system with a three-axis force sensor which can measure the spherical-object grasping force is developed. The three-axis force sensor is designed and fabricated, and the force measuring device is designed and manufactured using DSP(digital signal processing). Also, the grasping force test of men is performed using the developed finger-force measuring system, it was confirmed that the average force of men was about 120 N.

Development of Finger-force Measuring System with Six-axis Force/moment Sensor for Measuring a Spherical-object Grasping Force (6 축 힘/모멘트센서를 이용한 구물체 잡기 손가락 힘측정장치 개발)

  • Kim, Hyeon-Min;Yoon, Joung-Won;Shin, Hee-Suk;Kim, Gab-Soon
    • Journal of the Korean Society for Precision Engineering
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    • v.27 no.11
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    • pp.37-45
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    • 2010
  • Stroke patients can't use their hands because of the paralysis of their fingers. Their fingers are recovered by rehabilitating training, and the rehabilitating extent can be judged by grasping a spherical object. At present, the used object in hospital is only a spherical object, and can't measure the force of fingers. Therefore, doctors judge the rehabilitating extent by touching and watching at their fingers. So, the spherical object measuring system which can measure the force of their fingers should be developed. In this paper, the finger-force measuring system with a six-axis force/moment sensor which can measure the spherical-object grasping force is developed. The six-axis force/moment sensor was designed and fabricated, and the force measuring device was designed and manufactured using DSP (digital signal processing). Also, the grasping force test of men was performed using the developed finger-force measuring system, it was confirmed that the average force of men was about 120N.

Quantification of Acoustic Pressure Estimation Error due to Sensor Position Mismatch in Spherical Acoustic Holography (구형 음향 홀로그래피에서 측정위치 부정확성에 의한 음압 추정 오차의 정량화)

  • Lee, Seung-Ha;Kim, Yang-Hann
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.1325-1328
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    • 2007
  • When we visualize the sound field radiated from a spherical sound source, spherical acoustic holography is proper among acoustic holography methods. However, there are measurement errors due to sensor position mismatch, sensor mismatch, directivity of sensor, and background noise. These errors are amplified if one predicts the pressures close to the sources: backward prediction. The goal of this paper is to quantitatively examine the effects of the error due to sensor position mismatch on acoustic pressure estimation. This paper deals with the cases of which the measurement deviations are distributed irregularly on the hologram plane. In such cases, one can assume that the measurement is a sample of many measurement events, and the cause of the measurement error is white noise on the hologram plane. Then the bias and random error are derived mathematically. In the results, it is found that the random error is important in the backward prediction. The relationship between the random error amplification ratio and the measurement parameters is derived quantitatively in terms of their energies.

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Development of 3D Measuring System using Spherical Coordinate Mechanism by Point Laser Sensor (포인트 레이저 센서를 이용한 구면좌표계식 3차원 형상측정시스템 개발)

  • 맹희영;성봉현
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2004.10a
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    • pp.201-206
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    • 2004
  • Laser scanner are getting used for inspection and reverse engineering in industry such as motors, electronic products, dies and molds. However, due to the lack of efficient scanning technique, the tasks become limited to the low accuracy purpose. The main reasons for this limitation for usefulness are caused from the optical drawback, such as irregular reflection, scanning direction normal to measuring surface, the influence of surface integrity, and other optical disturbances. To overcome these drawback of laser scanner, this study propose the mechanism to reduce the optical trouble by using the 2 kinds of rotational movement axis and by composing the spherical coordinate to scanning the surface keeping normal direction consistently. So, it could be designed and interfaced the measuring device to realize that mechanism, and then it could acquisite the accurate 3D form cloud data. Also, these data are compared with the standard master ball and the data acquisited from the touch point sensor, to evaluate the accuracy and stability of measurement and to demonstrate the implementation of an dental tooth purpose system

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Design of a Multimode Piezoelectric Spherical Vector Sensor for a Cardioid Beam Pattern (심장형 빔 패턴을 위한 다중모드 압전 구형 벡터센서 설계)

  • Lim, Youngsub;Lee, Jaeyoung;Joh, Cheeyoung;Seo, Heeseon;Roh, Yongrae
    • The Journal of the Acoustical Society of Korea
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    • v.32 no.1
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    • pp.32-42
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    • 2013
  • Typical underwater piezoelectric spherical sensors are omni-directional, thus can measure the scalar quantity sound-pressure-magnitude only with the limitation not being able to measure the direction of the incoming wave. This paper proposes a method to simultaneously measure both the magnitude and direction of the sound wave with the spherical sensor. The method divides the piezoceramic sphere of the sensor into eight elements, and distinguishes the magnitude and direction of the sound pressure by combining the output voltage of the elements in a particular manner. Further, through the analysis of the sensitivity variation in relation to the structural parameters like radius and thickness of the piezoceramic sphere, we have suggested the way to improve the sensitivity of the vector sensor.

The Experimental Investigation of the Spherical Involute Bevel Gear (구형 인볼루트 베벨기어에 대한 실험적 연구)

  • 정동현;이형우;박노길
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.2
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    • pp.105-113
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    • 2000
  • For exact spherical involute bevel gear, serveral researchers had developed the mathematical models. The solid models of straight bevel gears are obtained and inspected to avoid interference by computer graphics. Furthermore, A gearbox is assembled by spherical involute bevel gears, which are manufactured by CNC machine. The transmission errors in the tooth mesh are measured by Laser sensor, are compared with the AGMA standard. This gearbox is found to be ranked AGMA Q10(JIS 3)

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Characteristics and Preparation of Gas Sensor Using Nano-ZnO Powders (나노 ZnO 분말을 이용한 가스센서 제작 및 특성연구)

  • Yu, Il
    • Korean Journal of Materials Research
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    • v.25 no.6
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    • pp.300-304
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    • 2015
  • Nanorod ZnO and spherical nano ZnO for gas sensors were prepared by hydrothermal reaction method and hydrazine method, respectively. The nano-ZnO gas sensors were fabricated by a screen printing method on alumina substrates. The gas sensing properties were investigated for hydrocarbon gas. The effects of Co concentration on the structural and morphological properties of the nano ZnO:Co were investigated by X-ray diffraction and scanning electron microscope (SEM), respectively. XRD patterns revealed that nanorod and spherical ZnO:Co with a wurtzite structure were grown with (100), (002), (101) peaks. The sensitivity of nanorod and spherical ZnO:Co sensors was measured for 5 ppm $CH_4$ and $CH_3CH_2CH_3$ gas at room temperature by comparing the resistance in air with that in target gases. The highest sensitivity to the $CH_4$ and $CH_3CH_2CH_3$ gas of spherical nano ZnO:Co sensors was observed at Co 6 wt%. The spherical nano ZnO:Co sensor exhibited a higher sensitivity to hydrocarbon gas than nanorod ZnO.

Acoustic Sources Localization in 3D Using Multiple Spherical Arrays

  • Wang, Fangzhou;Pan, Xi
    • Journal of Electrical Engineering and Technology
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    • v.11 no.3
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    • pp.759-768
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    • 2016
  • Direction of arrival (DOA) estimation of multiple sources using sensor arrays has been widely studied in the last few decades, particularly, the spherical harmonic analysis utilizing a spherical array. Both the number of sensors on the aperture and size of the sphere can affect the estimation accuracy dramatically. However, those two factors are conflicted to each other in a single spherical array. In this paper, a multiple spherical arrays structure is proposed to provide an alternative design to the traditional single spherical array for the spherical harmonic decomposition, to obtain better localization performance. The new structure consists of several identical spheres in a given area, and the microphones are placed identically on each sphere. The spherical harmonic analysis algorithm using the new multiple array structure for the problem of multiple acoustic sources localization is presented. Simulation results show that the multiple spherical arrays can provide a more accurate direction of arrival (DOA) estimation for the multiple sources than that of a single spherical array, distinguish several adjacent sources more efficiently, and reduce the number of microphones on each sphere without decreasing its’ estimation accuracy.