Fault Diagnosis of Piezoelectric Sensor Patches for Vibration Control Based on Multifeature Fusion and Improved SVM

Table 4

Hilbert marginal spectral characteristics of three types of piezoelectric patch signals under noise signal.

Hilbert marginal spectrum characteristics of the first five IMF components
Category	The frequency of the point with the maximum marginal spectral amplitude					Maximum value of marginal spectrum
Normal	218	182.5	54	45.5	31.5	0.00844	0.00577	0.00362	0.00415	0.00303
	156.5	174	69	40.5	23.5	0.01252	0.00594	0.00333	0.00390	0.00353
	176.5	176.5	102	49.5	28.5	0.00881	0.00826	0.00473	0.00334	0.00466
	163.5	175.5	82.5	40.5	27	0.01284	0.00616	0.00326	0.00413	0.00321
	159	113.5	68.5	44.5	23.5	0.01341	0.00656	0.00409	0.00337	0.00410
Broken	174	169.5	62.5	41	15	0.00753	0.00562	0.00422	0.00350	0.00272
	225.5	217.5	69.5	47.5	29	0.00738	0.00537	0.00453	0.00388	0.00308
	165.5	168	94	43	22	0.00837	0.00461	0.00357	0.00359	0.00386
	152.5	217	101	50	25	0.00658	0.00550	0.00375	0.00365	0.00360
	163.5	215	83	39	22.5	0.00916	0.00690	0.00532	0.00449	0.00377
Degummed	216.5	129.5	92	26.5	27.5	0.00626	0.00455	0.00332	0.00328	0.00289
	258	173.5	60.5	45.5	8.5	0.00480	0.00326	0.00463	0.00345	0.00322
	257.5	169.5	76	51	29	0.00489	0.00373	0.00411	0.00235	0.00344
	255.5	132	93.5	29	17	0.00561	0.00407	0.00343	0.00297	0.00269
	229.5	161	85	57.5	10.5	0.00506	0.00334	0.00408	0.00324	0.00319