Abstract: Based on the classical matching pursuit algorithm, the composite dictionary multi-atoms matching algorithm based on structural characteristics of signal is proposed, and applied to bearing fault diagnosis field. For the structural characteristics of the roller bearing fault signals, a composite dictionary combining the impulse time-frequency dictionary and the Fourier dictionary is constituted. Sparse decomposition and reconstruction algorithm of composite dictionary multi-atoms matching pursuit is researched and used to extracting fault features, and the threshold de-noising is introduced in the reconstruction algorithm. The analysis results of roller bearing fault experiment signals and engineering signals indicate that the impact failure characteristic extraction effect of composite dictionary multi-atoms matching algorithm based on structural characteristics is superior to single-atom matching algorithm, and hard threshold is superior to that without threshold.

Key words: Composite dictionary, Fault diagnosis, Multi-atoms matching, Threshold de-noising