| 摘要 |
PURPOSE:To detect the vibration state of a building, a machine tool, etc., at a high speed by detecting the apparent natural circular vibration frequency and attenuation ratio of vibrations of an object to be measured in real time from the vibration signal of the object to be measured. CONSTITUTION:A detecting device consists of an acceleration pickup 2 which detects vibrations of the object 1 to be measured, a charge amplifier 3, speed and displacement arithmetic circuits 4 and 5, etc. Then, vibration characteristics of the object 1 to be measured are approximated by a 1-freedom-degree linear vibration system with a natural circular vibration frequency omega0 and an attenuation ratio xsi and it is assumed that a noise having a flat spectrum up to a band omegac causes the vibrations. At this time, when the dispersion V0 of displacement vibrations of the object 1 to be measured, dispersion V1 of speed vibrations, and dispersion V2 of an acceleration signal are known, the natural circular vibration frequency omega0 and attenuation ratio xsi are found from equations I and II. Therefore, the natural circular vibration frequency and attenuation ratio are found in real time by a circuit which calculates the dispersion V0, dispersion V1, and dispersion V2 from the vibration signal of the object 1 to be measured and a circuit which calculates the natural circular vibration frequency omega0 and attenuation ratio xsi from said equations.
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