• Title/Summary/Keyword: Accelerometer.

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Study on Measurements of the In-Plane Vibration Intensity In a Beam With a Damped End (감쇠 단을 갖는 보의 면내 진동인텐시티 측정에 관한 연구)

  • Kim Chang-Yeol;Kil Hyun-Gwon;Hong Suk-Yoon
    • The Journal of the Acoustical Society of Korea
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    • v.24 no.7
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    • pp.371-378
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    • 2005
  • The objective or this paper is to measure the in-plane vibration intensity of a beam with a damped end that means the magnitude and direction of vibration power. Three experimental methods have been implemented to measure the in-plane vibration intensity over the beam. The first method is the accelerometer array method using two accelerometers. The second method is the frequency response function method using the only one accelerometer. The third method is the reference accelerometer method using a fixed reference accelerometer and another moving accelerometer. Those methods have been used to measure the spatial distribution of in-plane vibration intensity over the beam. The results obtained with those methods have been compared with each other. The results have been compared with an input power. It showed that the frequency response function method and the reference accelerometer method as well as the accelerometer array method can be effectively used to measure the in-plane vibration intensity in beams.

Analysis of Braking Response Time for Driving Take Based on Tri-axial Accelerometer

  • Shin, Hwa-Kyung;Lee, Ho-Cheol
    • The Journal of Korean Physical Therapy
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    • v.22 no.6
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    • pp.59-63
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    • 2010
  • Purpose: Driving a car is an essential component of daily life. For safe driving, each driver must perceive sensory information and respond rapidly and accurately. Brake response time (BRT) is a particularly important factor in the total stopping distance of a vehicle, and therefore is an important factor in traffic accident prevention research. The purpose of the current study was (1) to compare accelerometer. BRTs analyzed by three different methods and (2) to investigate possible correlations between accelerometer-BRTs and foot switch-BRTs, which are measured method using a foot switch. Methods: Eighteen healthy subjects participated in this study. BRT was measured with either a tri-axial accelerometer or a footswitch. BRT with a tri-axial accelerometer was analyzed using three methods: maximum acceleration time, geometrical center, and center of maximum and minimum acceleration values. Results: Both foot switch-BRTs and accelerometer-BRTs were delayed. ANOVA for accelerometer BRTs yielded significant main effects for axis and analysis, while the interaction effect between axis and analysis was not significant. Calculating the Pearson correlation between accelerometer-BRT and foot switch-BRT, we found that maximum acceleration time and center of maximum and minimum acceleration values were significantly correlated with foot switch-BRT (p<0.05). The X axis of the geometrical center was significantly correlated with foot switch-BRTs (p<0.05), but Y and Z axes were not (p>0.05). Conclusion: These findings suggest that the maximum acceleration time and the center of maximum and minimum acceleration value are significantly correlated with foot switch-BRTs.

Signal Processing Algorithm for Controlling Dynamic Bandwidth of Fiber Optic Accelerometer (광섬유 가속도계 센서의 동적구간 조절을 위한 신호처리 알고리즘 개발)

  • Kim, Dae-Hyun
    • Journal of the Korean Society for Nondestructive Testing
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    • v.27 no.4
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    • pp.291-298
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    • 2007
  • This paper presents a signal processing algorithm to control the dynamic bandwidth of a single-degree-of-freedom (SDF) dynamic sensor system. An accelerometer is a representative SDF sensor system. In this paper, a moire-fringe-based fiber optic accelerometer is newly used for the test of the algorithm. The accelerometer is composed of one mass, one damper and one spring as a SDF dynamic system. In order to increase the dynamic bandwidth of the accelerometer, it is needed to increase the spring constant or decrease the mass. However, there are mechanical difficulties of this adjustment. Therefore, the presented signal processing algorithm is very effective to overcome the difficulties because it is just adjustment in the signal processing software. In this paper, the novel fiber optic accelerometer is introduced shortly, and the algorithm is applied to the fiber optic accelerometer to control its natural frequency and damping ratio. Several simulations and experiments are carried out to prove the performance of the algorithm. As a result, it is shown that the presented signal processing algorithm is a good way to broaden the dynamic bandwidth of the fiber optic accelerometer.

Piezoelectric 6-dimensional accelerometer cross coupling compensation algorithm based on two-stage calibration

  • Dengzhuo Zhang;Min Li;Tongbao Zhu;Lan Qin;Jingcheng Liu;Jun Liu
    • Smart Structures and Systems
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    • v.32 no.2
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    • pp.101-109
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    • 2023
  • In order to improve the measurement accuracy of the 6-dimensional accelerometer, the cross coupling compensation method of the accelerometer needs to be studied. In this paper, the non-linear error caused by cross coupling of piezoelectric six-dimensional accelerometer is compensated online. The cross coupling filter is obtained by analyzing the cross coupling principle of a piezoelectric six-dimensional accelerometer. Linear and non-linear fitting methods are designed. A two-level calibration hybrid compensation algorithm is proposed. An experimental prototype of a piezoelectric six-dimensional accelerometer is fabricated. Calibration and test experiments of accelerometer were carried out. The measured results show that the average non-linearity of the proposed algorithm is 2.2628% lower than that of the least square method, the solution time is 0.019382 seconds, and the proposed algorithm can realize the real-time measurement in six dimensions while improving the measurement accuracy. The proposed algorithm combines real-time and high precision. The research results provide theoretical and technical support for the calibration method and online compensation technology of the 6-dimensional accelerometer.

Wafer Level Vacuum Packaged Out-of-Plane and In-Plane Differential Resonant Silicon Accelerometers for Navigational Applications

  • Kim, Illh-Wan;Seok, Seon-Ho;Kim, Hyeon-Cheol;Kang, Moon-Koo;Chun, Kuk-Jin
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.5 no.1
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    • pp.58-66
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    • 2005
  • Inertial-grade vertical-type and lateral-type differential resonant accelerometers (DRXLs) are designed, fabricated using one process and tested for navigational applications. The accelerometers consist of an out-of-plane (for z-axis) accelerometer and in-plane (for x, y-axes) accelerometers. The sensing principle of the accelerometer is based on gap-sensitive electrostatic stiffness changing effect. It says that the natural frequency of the accelerometer can be changed according to an electrostatic force on the proof mass of the accelerometer. The out-of-plane resonant accelerometer shows bias stability of $2.5{\mu}g$, sensitivity of 70 Hz/g and bandwidth of 100 Hz at resonant frequency of 12 kHz. The in-plane resonant accelerometer shows bias stability of $5.2{\mu}g$, sensitivity of 128 Hz/g and bandwidth of 110 Hz at resonant frequency of 23.4 kHz. The measured performances of two accelerometers are suitable for an application of inertial navigation.

Serially multiplexed FBG accelerometer for structural health monitoring of bridges

  • Talebinejad, I.;Fischer, C.;Ansari, F.
    • Smart Structures and Systems
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    • v.5 no.4
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    • pp.345-355
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    • 2009
  • This article describes the development of a fiber optic accelerometer based on Fiber Bragg Gratings (FBG). The accelerometer utilizes the stiffness of the optical fiber and a lumped mass in the design. Acceleration is measured by the FBG in response to the vibration of the fiber optic mass system. The wavelength shift of FBG is proportional to the change in acceleration, and the gauge factor pertains to the shift in wavelength as a function of acceleration. Low frequency version of the accelerometer was developed for applications in monitoring bridges. The accelerometer was first evaluated in laboratory settings and then employed in a demonstration project for condition assessment of a bridge. Laboratory experiments involved evaluation of the sensitivity and resolution of measurements under a series of low frequency low amplitude conditions. The main feature of this accelerometer is single channel multiplexing capability rendering the system highly practical for application in condition assessment of bridges. This feature of the accelerometer was evaluated by using the system during ambient vibration tests of a bridge. The Frequency Domain Decomposition method was employed to identify the mode shapes and natural frequencies of the bridge. Results were compared with the data acquired from the conventional accelerometers.

Exercise Recognition using Accelerometer Based Body-Attached Platform (가속도 센서 기반의 신체 부착형 플랫폼을 이용한 운동 인식)

  • Kim, Joo-Hyung;Lee, Jeong-Eom;Park, Yong-Chan;Kim, Dae-Hwan;Park, Gwi-Tae
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.11
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    • pp.2275-2280
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    • 2009
  • u-Healthcare service is one of attractive applications in ubiquitous environment. In this paper, we propose a method to recognize exercises using a new accelerometer based body-attached platform for supporting u-Healthcare service. The platform consists of a device for measuring accelerometer data and a device for receiving the data. The former measures a user's motion data using a 3-axis accelerometer. The latter transmits the accelerometer data to a computer for recognizing the user's exercise. The algorithm for exercise recognition classifies the type of exercise using principle components analysis(PCA) from the accelerometer data transformed by discrete fourier transform(DFT), and estimates the repetition count of the recognized exercise using a peak detection algorithm. We evaluate the performance of the algorithm from the accuracy of the recognition of exercise type and the error rate of the estimation of repetition count. In our experimental result, the algorithm shows the accuracy about 98%.

Vibration-Monitoring of a Real Bridge by Using a $Moir\'{e}$-Fringe-Based Fiber Optic Accelerometer

  • Kim, Dae-Hyun;Lee, Jong-Jae
    • Journal of the Korean Society for Nondestructive Testing
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    • v.27 no.6
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    • pp.556-562
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    • 2007
  • This paper presents the use of a novel fiber optic accelerometer system to monitor ambient vibration (both wind-induced one and vehicle-induced) of a real bridge structure. This sensor system integrates the $Moir\'{e}$ fringe phenomenon with fiber optics to achieve accurate and reliable measurements. A low-cost signal processing unit implements unique algorithms to further enhance the resolution and increase the dynamic bandwidth of the sensors. The fiber optic accelerometer has two major benefits in using this fiber optic accelerometer system for monitoring civil engineering structures. One is its immunity to electromagnetic (EM) interference making it suitable for difficult applications in such environments involving strong EM fields, electrical spark-induced explosion risks, and cabling problems, prohibiting the use of conventional electromagnetic accelerometers. The other is its ability to measure both low- and high-amplitude vibrations with a constantly high resolution without pre-setting a gain level, as usually required in a conventional accelerometer. The second benefit makes the sensor system particularly useful for real-time measurement of both ambient vibration (that is often used for structural health monitoring) and strong motion such as earthquake. Especially, the semi-strong motion and the small ambient one are successfully simulated and measured by using the new fiber optic accelerometer in the experiment of the structural health monitoring of a real bridge.

The Implementation of Digital Input System for Cellular-phone using the Accelerometer and PIC (Accelerometer Sensor와 PIC를 이용한 Cellular-phone용 Digital Input System 구현)

  • 여영호;손수국;윤나서
    • Proceedings of the IEEK Conference
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    • 2003.07d
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    • pp.1495-1498
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    • 2003
  • This paper has been studied about designed digital-pen using PIC and Accelerometer and about calculated acceleration by the measure analog signal from accelerometer Finally, we calculate the coordinates and the tilt about the acceleration and discuss the possibility of using the digital-pen from cellular phone. And we discuss about the full-duplex communication of input data that displayed in cellular phone.

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