Ultra-low frequency mechanical excitations are omnipresent in our surrounding environment, but the efficient exploitation of them is generally difficult because they normally drive the widely reported cantilevered harvesters to work under non-resonant conditions. Although the frequency up-conversion strategy has been proposed to mitigate this issue, it usually leads to complicated structures. This paper reports a novel energy harvesting approach based on the twisting vibration of a string-driven rotor. To examine the feasibility of this approach, an electromagnetic energy harvester is designed, which is composed of a lid, a rotor with embedded magnets, a pendant, and a tube with pick-up coils attached to the outer surface. The rotor is suspended between the lid and the pendant through a piece of string, and then actuated by the ambient excitations through the string. Under the excitations produced by a crank-slider mechanism, the designed harvester can generate useful electric outputs that are proportional to the excitation amplitude, the initial angle between the pendant and lid, and the excitation frequency. Moreover, the harvester can also provide 0.034 mW power when it is periodically pulled by the human hand at approximately 1 Hz. This study demonstrates the potential application of the string-driven rotor in collecting energy from ultra-low frequency excitations.

中文翻译：

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基于扭曲振动的能量收集器，用于超低频激励

超低频机械激励在我们周围的环境中无处不在，但是通常很难对其进行有效利用，因为它们通常会驱动广泛报道的悬臂式收割机在非谐振条件下工作。尽管已经提出了频率上转换策略来减轻这个问题，但是它通常导致结构复杂。本文报道了一种基于弦驱动转子扭转振动的新型能量收集方法。为了检验这种方法的可行性，设计了一种电磁能量收集器，该收集器由一个盖子，一个带有嵌入式磁体的转子，一个悬垂件以及一个在外表面连接有拾波线圈的管组成。转子通过一根绳子悬挂在盖子和吊坠之间，然后由穿过琴弦的环境激励来驱动。在曲柄滑块机构产生的激励下，设计的收割机可以产生有用的电输出，这些输出与激励幅度，悬垂物和盖子之间的初始角度以及激励频率成比例。此外，当收割机被人的手以大约1 Hz的频率周期性拉动时，它还可以提供0.034 mW的功率。这项研究证明了弦驱动转子在收集超低频激励能量方面的潜在应用。当人手以大约1 Hz的频率周期性地拉动收割机时，收割机还可以提供0.034 mW的功率。这项研究证明了弦驱动转子在收集超低频激励能量方面的潜在应用。当用人手以大约1 Hz的频率定期拉动收割机时，收割机还可以提供0.034 mW的功率。这项研究证明了弦驱动转子在收集超低频激励能量方面的潜在应用。