Research on Dynamic Characteristics of Hydraulic Pump Slipper With Wear Based on Operational Modal Analysis

Abstract

The dynamic characteristic parameters can reflect the dynamic mechanism of hydraulic pump in fault conditions, which is an important basis for accurate diagnosis and condition assessment. It is difficult to carry out model accurately and solve in fault conditions by the general dynamic theory method. Therefore, taking the wear fault of slipper as an example, the operational modal analysis method is used to extract and analyze the dynamic parameters feature in different wear degrees. Considering the excitation characteristics of axial piston pump, the Op.PolyMAX method is used to identify the multi-order modal parameters including harmonic modals, and the Morlet wavelet cluster bandpass filter is used to separate the time domain signals corresponding to each modal frequency. According to the difference of statistical characteristics between the structure random response and harmonic response, the harmonic modal caused by the pump rotation frequency is eliminated, and then the first three order intrinsic modals of the axial piston pump are obtained. The sensitive dynamic characteristic parameters of the slipper wear fault are extracted by comparing the operational model parameters of hydraulic pump under normal and slipper wear fault condition.