Title Fault Diagnosis Method of Gearbox Multifeature Fusion Based on Quadratic Filter and QPSO-KELM

Figure 12

Time-frequency feature based on 2DPCA-STFT: (a) normal; (b) miss tooth fault; (c) break tooth fault; (d) wear tooth fault; (e) bearing inner race fault; (f) bearing outer race fault.

(a)

(b)

(c)

(d)

(e)

(f)