In the following we examine the variations of mechanical motion and harvested power with the base excitation frequency. The effects are different depending on the level of base accelerations. We therefore conduct three series of tests and illustrate the results in Fig. 11, Fig. 12 and Fig. 13. (a) (b) (c) Fig. 11: Relation between the frequency of the 1.18 m.s-2 base excitation and and a) power from piezoelectric patched, b) power from electromagnetic coils, c) phase portrait. 5 6 7 8 9 10 -6 10 -5 10 -4 10 -3 base excit. freq. (Hz) PZT power (Watt) a b =1.1778 m.s -2 small amplitude Limit Cycle chaos 5 6 7 8 9 10 -7 10 -6 10 -5 10 -4 base excit. freq. (Hz) EM power (Watt) a b =1.1778 m.s -2 small amplitude Limit Cycle chaos -0.02 -0.01 0 0.01 0.02 -0.2 0 0.2 5 6 7 8 9 base accel. (m.s -2 ) a b =1.1778 m.s -2 xt (m) vt (m.s -1 ) 474
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