Spindle health diagnosis based on analytic wavelet enveloping

A new diagnostic technique for identifying structural defects in spindles was developed based on the analytic wavelet transform. The new technique extracts defect-induced impulses from the spindle vibration signal and constructs their envelopes in a single step, eliminating the need for intermediate operations as traditionally required. Theoretical background of the analytic wavelet transform was first introduced, and numerical simulation was then conducted on a synthetic signal. The result was subsequently compared with vibration signals measured on a spindle test bed. It was confirmed that the developed technique is effective in detecting defect-induced impulses buried in the spindle vibration signals that otherwise were undetectable using the traditional spectral techniques.