Uncertainty Analysis of Excitation Conditions on Performance of Nonlinear Monostable Energy Harvesters

Nonlinear energy harvesters were found to be sensitive to excitation conditions. In order to reveal the influence mechanism of the excitation condition on the energy harvesting performance, this paper presents an uncertainty analysis for nonlinear monostable energy harvesters (NMEHs). An improved interval extension based on the second-order Taylor's series is presented as a new uncertainty analysis method. A mathematic example is used to demonstrate that the bounds of responses based on this method are more accurate than the classic interval extension when the dependence of the response on the uncertain variable is nonlinear. Meanwhile, the results from the Monte Carlo simulation are used to verify the accuracy of the proposed method. It is confirmed that the proposed method is suitable for quantifying the propagation of the uncertain level and frequency of the excitation for the NMEH. The results show that the output voltage of the NMEH is more sensitive to the frequency than the level of excitation, for which the influence mechanism is revealed.