Abstract: The non-contact measurement vibration signals obtained by blade tip-timing sensor mounted on the machinery case are discrete undersampling signals. A method for the reconstruction of rotating blade vibration signal with interpolation technique at even speed is presented. The reconstructive signal is helpful for the identification of the blades vibration amplitude which is one of the features for rotating assemblies fault diagnosis. With the analysis of signal’s sampling and reconstruction model, the reconstruction is based on a finite number of samples by timelimited kernels which are constructed with the involvement of B-splines. The reconstruction has lower truncation error and less calculation as a result of the rapid constringency of higher-order B-splines. The simulation shows that the precision of signal reconstruction is highly dependent on the stability of sampling rate, which is related with the rotation rate. Gas excitation experimentation on the blade vibration test bed is introduced to test and verify the performance of this method in practice.

Key words: Blade tip-timing, Blade vibration, Interpolation, Signal reconstruction, Undersampling