Synchronous Response of Rotor Components by Rotated Wavelet Probing

Theanalysis of the synchronous response of the rotor components can be carried out efficiently using time- frequency methods based on the continuous wavelet transform. The wavelet transform provides a measure that may be regarded as weighted averaging of the signalamplitude with the support of the wavelet. This averaging area is referred to as Heisenberg box and, for Gabor wavelet, has an elliptical shape. In the case of wavelet probing, the estimation of the amplitude and phase needs to squeeze in frequency direction the Heisenberg box (HB) for increasing the resolution. The limit of this technique arise when, in proximity of the resonance crossing, the HB of the wavelet intersects both the synchronous and non-synchronous response components. This interaction is particularly important when the dynamical system is time-variant due to the variation of the rotor speed. This paper proposes the estimation of the synchronous response with a time-frequency method based on a wavelet whose HB is an ellipse arbitrarily rotated to increase the capability of separating the signal components. After the analytical definition of the wavelet, the proposed method is applied both to simulated and experimental data.