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WOLFE, MASRI, CAFFREY
Transforming the computed Chebyshev polynomial coefficients to an equivalent
Power Series representation allows direct comparison of individual parameter shifts.
Figure 2.3 illustrates the mean shift of the identified system stiffness parameter when
the simulated stiffness and Duffing epsilon values were degraded by 5% individually.
As expected, the identification algorithm discnminates the system change, noting
mean values of approximately 42.4, 40.0, and 42.5 for the reference, degraded
stiffness and degraded epsilon cases, respectively. These values yield a stiffness
degradation of 5.8% for the case wherein the stiffness parameter was degraded by 5%,
and a 0.1% change in the identified stiffness parameter when the nonlinear Duffing
term epsilon is degraded by 5%. These results confirm the ability of the algorithm to
detect and discriminate system change even under noise pollution.
0.03
0.02
0.01
-10 15 40 65 90
Figure 23 Comparison of degraded stiffness and epsilon mean shift to reference case
(undegraded)