We carried out a numerical analysis and an experimental investigation of the nonlinear resonance characteristics of an electromagnetic vibration energy harvester driven by impacts with a ball. In our prototype device, a cantilever beam is used as a frequency up-converter, and a rigid spherical ball is used to generate impact forces acting upon the cantilever. The purpose of this study is to investigate the feasibility of downsizing the device to assess the potential of these devices for energy harvesting from human-induced low-frequency vibrations. To this end, we developed a mathematical model of the device, which accounts for the sticking motion after impact. The model accuracy was verified by comparing the nonlinear harmonics of the vibration amplitude with the experimental results. The numerical analysis was implemented in an in-house code in MATLAB. On impact with the ball, the power density was 0.8 µW/cm³ at 10.5 Hz for a cantilever with a natural frequency of 34 Hz, which is 140 times larger than that without the ball. It was found that with a shorter cantilever the power density achieved is comparable to larger cantilevers owing to the high-frequency nonlinear harmonic vibrations. The critical gap size between the cantilever and the ball where the power density drops off was estimated from the numerical analysis.

我们对由球撞击驱动的电磁振动能量收集器的非线性共振特性进行了数值分析和实验研究。在我们的原型装置中，悬臂梁用作上变频器，刚性球形球用于产生作用在悬臂上的冲击力。本研究的目的是研究缩小设备尺寸的可行性，以评估这些设备从人为低频振动中收集能量的潜力。为此，我们开发了该设备的数学模型，该模型解释了撞击后的粘滞运动。通过将振动幅度的非线性谐波与实验结果进行比较，验证了模型的准确性。数值分析是在 MATLAB 的内部代码中实现的。击球时，功率密度为 0.8 µW/cm^{对于自然频率为 34 Hz 的悬臂，在 10.5 Hz 时为3}，比没有球的悬臂大 140 倍。结果发现，由于高频非线性谐波振动，使用较短的悬臂实现的功率密度与较大的悬臂相当。从数值分析估计悬臂和功率密度下降的球之间的临界间隙尺寸。