A novel vibration velocity measurement method for electromagnetic vibrators

摘要

A novel vibration velocity measurement method for electromagnetic vibrators based on a vibration velocity measurement coil that can extract the vibration velocity without any extra commercial vibration sensors is proposed. An extra and independent vibration velocity measurement coil is wound on the armature together with the drive coil of the vibrator, and a velocity extractor is designed to extract the vibration velocity from the output voltage of the velocity measurement coil. The frequency response and the linearity of the vibration velocity measurement system are calibrated through a series of experiments. The uncertainty analysis shows that the uncertainties (k= 2) in the amplitude of the sensitivity and the phase shift are 1% and 2 degrees respectively in the frequency band from 5 to 100 Hz, and the uncertainties (k= 2) in the amplitude of the sensitivity and the phase shift are 3% and 4 degrees respectively in the frequency band from 100 to 1000 Hz. The proposed method is not only simple in structure, but also low in cost, and it could well be applied in the various types of electromagnetic vibrators, whose vibration level should easily be got.