Numerical and Experimental Investigation on Parameter Identification of Time-Varying Dynamical System Using Hilbert Transform and Empirical Mode Decomposition

Table 3

Identification error of frequency and damping ratio at different time instant (MDOF Example 1).

Time instant (sec.)	Freq. (1st)		Freq. (2nd)		Damp. (1st)		Damp. (2nd)
	Theory	Identify	Theory	Identify	Theory	Identify	Theory	Identify
2	6.057	6.016	14.642	14.592	0.149	0.149	0.012	0.012
4	4.516	4.578	12.046	11.988	0.088	0.083	0.010	0.011
6	5.616	5.606	17.177	17.171	0.109	0.109	0.012	0.014
8	6.478	6.502	15.769	15.934	0.150	0.150	0.013	0.013
10	4.776	4.743	11.974	11.974	0.100	0.102	0.011	0.011
12	5.336	5.332	17.032	17.054	0.106	0.106	0.012	0.011
16	5.003	4.928	12.161	12.109	0.117	0.117	0.010	0.010
20	6.980	2.977	17.603	20.00	0.145	0.137	0.015	0.016