In recent years, energy harvesting technology has provided a promising solution for powering low-power sensors. Rotational motions are ubiquitous in nature and human activities, making the design and study of rotational energy harvesters highly significant for the development of the Internet of Things. Previous studies have shown that nonlinear bistability and multiple degrees of freedom (MDOF) can significantly enhance the output power and operating frequency bandwidth of rotational energy harvesters. However, the bistability introduces the nonlinear stiffness into the MDOF harvester, resulting in the oscillations in high-energy or low-energy orbits that both may occur depending on the system condition. Therefore, this paper proposes a method to excite the high-energy orbit of two degree-of-freedom rotational bistable energy harvesters (2-DOF-RBEH) at ultra-low frequencies utilizing the phase difference of equivalent excitation. A theoretical model describing its dynamic response and output voltage is derived based on Hamilton’s principle. Experiments are conducted to validate the model, and the output voltage responses of the harvester with zero phase difference (HZPD) and the harvester with half phase difference (HHPD) are compared. Results show that the HHPD more easily enter into the high-energy orbit at ultra-low rotational frequencies. Due to this, the output power of HHPD is increased by up to 2187% compared to HZPD, and the frequency bandwidth entering the high-energy orbit is increased by up to 466%. In addition, this study analyzes the dynamic mechanism by which the equivalent excitation phase difference triggers the high-energy orbit and explores the effect of excitation angles on the dynamic response and performance of the HHPD. These investigations offer new insights for the design of high-performance ultra-low-frequency bistable rotational energy harvesters.

中文翻译：

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通过相位差触发 2-DOF 双稳态旋转能量收集器的高能轨道


近年来，能量收集技术为低功耗传感器供电提供了一种前景广阔的解决方案。旋转运动在自然界和人类活动中无处不在，这使得旋转能量收集器的设计和研究对物联网的发展具有重要意义。以往的研究表明，非线性双稳态和多自由度 （MDOF） 可以显著提高旋转能量采集器的输出功率和工作频率带宽。然而，双稳态将非线性刚度引入 MDOF 采集器，导致高能或低能轨道上的振荡，这两种情况都可能发生，具体取决于系统条件。因此，本文提出了一种利用等效激励的相位差以超低频率激发两个自由度旋转双稳态能量收集器 （2-DOF-RBEH） 的高能轨道的方法。描述其动态响应和输出电压的理论模型基于汉密尔顿原理推导出来。通过实验验证了模型，并比较了零相位差 （HZPD） 和半相位差 （HHPD） 的采集器的输出电压响应。结果表明，HHPD 在超低旋转频率下更容易进入高能轨道。因此，HHPD 的输出功率与 HZPD 相比提高了 2187%，进入高能轨道的频率带宽提高了 466%。此外，本研究分析了等效激发相位差触发高能轨道的动力学机制，并探讨了激发角对 HHPD 动力学响应和性能的影响。 这些研究为高性能超低频双稳态旋转能量收集器的设计提供了新的见解。