• Title/Summary/Keyword: 진동오차

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Defects Diagnosis of Ball Bearings by Neural Network (신경회로망을 이용한 볼 베어링의 결함진단)

  • 양보석;최성필;최원호;김진욱
    • Journal of Advanced Marine Engineering and Technology
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    • v.18 no.5
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    • pp.36-45
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    • 1994
  • This paper describes how to identify standard numbers and to diagnose defects of the ball bearings. The first stage of the networks is a procedures for identifying standard numbers of the bearings, and the next stage carries out the diagnosis of defects on the outer race and the inner race of bearings. The identification and the diagnosis of bearings were carried out by simulations and experiments.

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Development of the Multichannel Vibration Monitoring System (다채널 진동 모니터링 장치 개발)

  • Hong, Tae-Yong;Park, Soo-Hong
    • The Journal of the Korea institute of electronic communication sciences
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    • v.11 no.7
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    • pp.671-676
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    • 2016
  • This study is about design for the Rotational Instrument of the Industry factory which is used management safety and maintenance. We developed the multichannel vibration monitering system of the self-diagnosis for middle level CMS(Condition Monitoring System) market, and that system are new features to the expandability and flexibility. Normally one channel is used for treating one signal, but developed instrument can treat four channel with one signal processing card. One rack have redundant power supply and displace and it can check vibration measurement value in field without computer. Bearing fault detection is fundamental of vibration surveillance, but sometimes can not check with vibration velocity and acceleration. So it need the filtering and the amplitude modulation on the acceleration enveloping technology when irregular vibration is happened. We developed the vibration analysis instrument which is applied such technology. And the development prototype shows activated within the vibration error limit.

PRECISION IDENTIFICATION OF ACTUATOR DISTURBANCE PARAMETER BY FREQUENCY COMPENSATION (주파수 보정법에 의한 구동기 외란 파라미터 정밀 결정)

  • Lee Hyunho;Cheon Dong-Ik;Oh Hwa-Suk
    • Bulletin of the Korean Space Science Society
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    • 2005.04a
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    • pp.138-142
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    • 2005
  • A reaction wheel, an actuator for satellite attitude control, produces disturbance torque and force as well as its axial control torque. The disturbances have an influence on the pointing stability of high precision satellites. The measurement of disturbances for such a satellite, therefore, is necessary. The wheel's rotation, however, causes the vibration of the table and its vibration induces measurement errors, especially large near the resonance frequency of the Measurement table. For the purpose of overcoming these defects, a calibration method using frequency compensation is suggested in this paper. Disturbance parameters are identified from data examined by frequency compensation. Measurement frequency range can be expanded far higher than the resonance frequency, since the degradation of data accuracy caused by its vibration is well alleviated even in the resonance area.

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Correction of Error due to Camera Vibrating During Detecting Steam Leakage by Using Image (영상을 이용한 누설탐지에서 카메라 진동 오차 보정)

  • Choi, Young-Chul;Jeon, Hyeong-Seop;Son, Ki-Sung;Park, Jong Won
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.24 no.10
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    • pp.795-801
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    • 2014
  • Steam leakage is one of the major issues for the structural fracture of pipes of nuclear power plants. Therefore a method to inspect a large area of piping systems quickly and accurately is needed. Recently, the research detecting the steam leakage by using camera image is introduced. However, this method has a disadvantage. If a camera oscillates, it cannot detect a steam leakage exactly. In this paper, the technique that reduces the error due to a camera shaking is proposed. To verify the proposed method, we have performed the experiments for the oil leakage experiments. The results show that the technique can calibrate the error due to camera shaking.

Improvement of Multi-beam Echo Sounder's Depth Accuracy (다중빔 음향측심기 수심 정확도 개선)

  • Choi Chul Eung;Kim Youn Soo;Suh Yong Cheol
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.23 no.1
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    • pp.1-8
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    • 2005
  • Multi-beam echo sounder is more precise and efficient than single beam echo sounder relatively because it is able to survey a wide area with 3 times or 4 times swath width as much as the depth of water using multi-beam echo sounder. It is sure to be needed to control supplementary equipment accurately, however, because the principle of creation and measurement of the beam is elaborate and influenced a great deal by vessel's motion. We analyzed using visual and statistical methods in both sections of the depth of water where were the places of the center of the beam and ± 45° angles from the central beam to improve the precise of Multi-beam echo sounder in this study. In result, it was required to control supplementary equipment because of errors from the vibration of an inertia governor and misalignment of extra units. Therefore, we reduced the vibration from the vessel's engine by sticking rubbers to the inertia governor and measured the offset values of extra units accurately, converted them to the values of horizontal position and lined up. In result, the precise in sounding the depth at the place of ± 45° from the center of the beam was improved from the level of the 1st order to the special order in a hydrographic survey of the IHO S44 standards and a phenomenon of ripple patterns in the overlapped area by misalignment was decreased remarkably.

Very Large Scale Analysis of Surfaces for Diamond Turned Machine Diagnosis (다이아몬드 선삭 가공기의 진단을 위한 대영역 표면 해석)

  • 김승우;장인철;김동식
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.05a
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    • pp.687-691
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    • 2000
  • Diamond turning machines for manufacture of precision optics require deliberate diagnosis to ensure that all the machine elements are properly operating, kinematically, dynamically and thermally, to produce demanded work qualities. One effective way is to directly inspect topographical features of work surfaces that have been carefully generated with prescribed machining conditions intended to exaggerate faulty consequences of any ill-operating machine elements. In this research, a very-large-scale Phase measuring interferometric system that has been developed for years at Korea Advanced Institute of Science and Technology is used to fulfill the metrological requirements fur the surface analysis. A special stitching technique is used to extend the measuring range, which integrates all the patches that are separately sampled over the whole surface while moving the stage. Then, the measured surface profile is analyzed to releated the machine error sources. For this, zernike polynomial fitting is used together with the wavelet filter and the fourier transform. Experimental results showed that the suggested technique in this study is very effective in diagnosing actual diamond turning machines

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Wiggle-free Finite Element Model for extended Boussinesq equations (확장형 Boussinesq FEM model의 수치진동오차 개선)

  • Woo, Seung-Buhm;Choi, Young-Kwang;Gonzalez-Ondina, Jose M.
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.22 no.1
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    • pp.47-57
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    • 2010
  • Subgrid scale stabilization method is applied to Woo and Liu(2004)'s extended Boussinesq FEM numerical model to eliminate the 2dx wiggles. In order to optimize the computational efficiency, Hessian operator is introduced and the matrix of velocity vector is combined to one matrix for solving matrix equations. The mass lumping technique is also applied to the matrix equations of auxiliary variables. The newly developed code is applied to simulate Vincent and Briggs(1989)' wave transformation experiments and the results show that the numerical solution is almost wiggle-free and it matches very well with experimental data. Due to improvement of computational efficiency and wiggle reduction, it is plausible to apply this model to a realistic problem such as harbor oscillation problems.