Weak signal extraction of micro-motor rotor unbalance based on all-phase fast Fourier transform

Abstract

To improve the dynamic balancing accuracy of the micro-motor rotor, an unbalanced vibration feature extraction based on an all-phase fast Fourier transform (APFFT) method is proposed. The amplitude and phase of the signal are extracted by spectrum analysis after windowing the unbalanced signal. The mathematical model is derived to simulate the weak signal of rotor unbalance. The simulation results show that this method is accurate in extracting the weak signal of the rotor under different noise levels. The micro-motor rotor unbalanced test system is developed for experimental validations. The accuracy and stability of the vibration amplitude and phase extracted by the APFFT are better than the accuracy and stability from the hardware filtering method. The rotor unbalance is reduced by more than 80%. Furthermore, secondary balance of the rotor after the first balance is carried out. The proposed method can still extract the residual unbalance of the rotor. The results demonstrated that the proposed method can achieve a reduction rate of 90% and the accuracy is within 5mg, verifying the effectiveness of the proposed method for high-precision rotor dynamic balance.

Keywords

all-phase fast Fourier transform / feature extraction / rotor dynamic balance / weak signal

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2024 2024 The Authors. International Journal of Mechanical System Dynamics published by John Wiley & Sons Australia, Ltd on behalf of Nanjing University of Science and Technology.