Adaptive demodulation extraction transform for fault diagnosis of rotating machinery

Abstract The accurate analysis of close and crossed frequency components is a challenge for the existing time–frequency analysis methods due to energy interference in the adjacent and crossing parts. In addition, the energy error at the intersection is caused because the energy value is superimposed repeatedly. To solve these problems, a new adaptive demodulation extraction transform (ADET) is proposed in this paper. An instantaneous frequency (IF) trajectory estimation method and an amplitude extraction (AE) matrix are designed to accurately identify the adjacent and crossing frequencies. The IF trajectory is calculated using the particle swarm optimization algorithm and the generalized demodulation technique. The AE matrix extracts the energy value from the time–frequency domain by a position function, which converts the IF trajectory to corresponding time–frequency information. Moreover, an iteration procedure is designed to avoid the superposition of energy at the crossing point. The effectiveness of ADET is confirmed through simulated and experimental signals.