A fault characteristics extraction method for rolling bearing with variable rotational speed using adaptive time-varying comb filtering and order tracking

The fault characteristics of rolling bearing with variable rotational speed are usually related to shafting speed and vary with time. Moreover, the rolling bearing fault characteristics are easily submerged by the noises. To address these issues, an adaptive time-varying comb filtering (ATVCF) method that combines the merits of comb filter and adaptive time-varying filtering (ATVF) is proposed and applied to extract the fault-related component from the envelope signal of rolling bearing. And on this basis, via the joint application of ATVCF and order tracking (OT), a fault characteristics extraction methodology for rolling bearing with variable rotational speed, namely ATVCF-OT, is developed. In the ATVCF-OT, the ATVCF method can adaptively extract time-varying harmonic components containing rolling bearing fault information from the rolling bearing fault vibration signal, and the OT analysis can effectively stabilize the time-varying rolling bearing fault features. Therefore, the ATVCF-OT methodology is particularly suitable for fault feature extraction of rolling bearing with variable rotational speed. Simulation and experimental results indicate that the ATVCF-OT method can effectively remove the fault-unrelated components and highlight the fault features of rolling bearing. The comparisons with the direct envelope order method and the ensemble empirical mode decomposition (EEMD)-based envelope order method demonstrate the advantages of the proposed ATVCF-OT method.