Modeling and analysis of the friction in a non-linear sliding-mode triboelectric energy harvester

非线性滑动式摩擦发电机的摩擦建模与分析

Friction plays a pivotal role in the sliding-mode triboelectric energy harvester(TEH),which not only enables the charge transfer between two dielectrics,but also influences the energy harvesting performance by affecting the dynamic response of the TEH.How to evaluate the effects of the friction on TEHs is important for optimizing TEHs in engineering practices.In order to analyze the effects of the friction on the dynamic response and evaluate the energy harvesting performance ofTEHs,the paper models the friction of a devised non-linear TEH based on the Coulomb friction model and the Macro-slip friction theory.The TEH equips a pair of magnets,rendering a switching between the bistability and the monostability by tuning the distance between two magnets.The dynamic model of the non-linear TEH is established by the extended Hamilton principle.The effects of friction in slidingmode TEH are dissected in detail.The influences of parameters on both the mechanical and electrical responses are also systemically studied to explore an optimal energy harvesting performance in the low-frequency range.This work provides a guideline for designing and accurately analyzing a sliding-mode TEH.

由于静电感应效应,滑动式摩擦发电机(TEH)在滑动摩擦过程中发生电荷转移,从而实现对机械能量的俘获.摩擦不仅直接影响滑动式TEH中介电质之间的电荷转移过程,还会改变TEH的动力学响应进而影响其能量收集性能.因此,研究摩擦对滑动式TEH的影响规律对评估其环境振动能俘获性能具有重要意义.本文设计了一种非线性滑动式TEH,并通过调整磁块之间的距离实现了双稳态和单稳态的自由切换,从而使其具有不同的运动力学机制.基于库仑摩擦模型和宏观滑动摩擦模型,文章建立了滑动式TEH的理论摩擦模型,进一步,应用哈密顿原理建立了相应的动力学模型,分析了摩擦对滑动式TEH性能的影响规律。为进一步探究TEH在低频下的能量收集效率,文章还系统研究了关键参数对TEH动力学行为和电学输出响应的影响,研究结果为滑动式TEH的设计与分析提供了理论参考。