Modal parameter identification for CNC machine tools using Wavelet Transform

The paper presents a new use of the Continuous Wavelet Transform for modal parameter identification applied to CNC machine tools. Firstly, the resonant frequencies and damping ratios of the CNC machine tool axis drive are estimated in the frequency domain using the transmissibility relation at resonance. The experimental Bode diagrams are determined using a novel measurement practice for the decoding of signals generated by a position encoder. This paper focuses on a novel application of the Continuous Wavelet Transform to identify the resonance frequencies and corresponding damping ratios of the CNC machine tool axis drive. The proposed method has the ability to detect variations in the amplitude levels of weak components embedded in strong noise and non-stationary processes. The superior ability of the Wavelet Transform to identify accurately modal parameters is demonstrated by comparing the results of the two different methods. (C) 2003 Elsevier Science Ltd. All rights reserved.