Blind interpolation for multi-frequency blade tip timing signals

Abstract

Blade tip timing (BTT) is a promising non-contact on-line monitoring technique for rotor blades. Although various analytical methods for BTT signals have been developed, their accuracy and stability still need to be improved for subsequent blade damage detection. This paper derives and validates a blind interpolation method for multi-frequency BTT signals (BIMF). It is an integration of two novel algorithms proposed by this paper: (1) the multi-band interpolation (MBI) algorithm breaks the single-band limitation of established interpolation methods, and is capable of accurate and stable spectrum identification and waveform reconstruction when the approximate frequency distribution is known; (2) the real signal-based multiple signal classification (RSMUSIC) algorithm provides reliable prior knowledge of frequency for MBI. Simulation results verify the accuracy of the proposed methods and the advantages of BIMF over the BTT-based compressed sensing algorithms. Experimental results also validate the accuracy and stability of BIMF in spectrum identification.