Analysis of non-stationary signal of a sudden unbalanced spindle based on wavelet noise reduction and short-time Fourier transformation

Since the response of a spindle with sudden unbalance shows non-stationary characteristics which cannot be extracted with signal processing methods using traditional Fourier transformation. To tackle this problem, a new signal extracting method combining wavelet de-noising technique and short time Fourier transformation was proposed. The non-stationary signal of the spindle was filtered and reconstructed with the wavelet de-noising technique. Then, the amplitude of the unbalance response was acquired with the short time Fourier transformation. The feasibility and accuracy of the proposed method were verified with numerical simulations and practical experiments.