Fault Diagnosis of Hydraulic Pumps Using PSO-VMD and Refined Composite Multiscale Fluctuation Dispersion Entropy

Figure 7

Time domain waveforms of original vibration signals. (a) Normal working state. (b) Single plunger loose slipper. (c) Double plungers loose slipper. (d) Piston shoe wear.

(a)

(b)

(c)

(d)