基于组合非线性的多稳态宽带能量采集不同势阱结构的设计与比较

Multi-stable Wideband Energy Harvesting:A Design and Comparison of Different Potential Well Configurations

为提高低频和宽带下能量采集器的功率密度,提出一种新型多稳态宽带能量采集装置。该采集器通过悬臂梁-止档接触与磁弹性相结合的非线性方法得到多种稳态类型。采集器的全局振幅受到接触的限制,但阱间运动提高了采集效率。本文确定多稳态的形成机制和不同磁体结构的相关参数区域;建立采集器的机电耦合模型来描述其动态特性;为探讨势阱结构对多稳态能量采集的影响,建立具有4种典型势阱结构的能量采集器,并通过实验验证其等效非线性恢复力;采用数值方法研究和实验验证了这4种结构在不同激励水平下的动态特性。结果表明,当外部激励超过临界强度时,深度不均匀的多势阱和较浅的外势阱比均匀深度的多势阱更适合所提出的系统。此外,通过提高采集器效率和限制末端质量的全局振幅,本文提出的多稳态系统实现了比传统系统高6.3倍的功率密度。

To improve the power density of energy harvesting from wide-bandwidth and low-frequency operation,a new multi-stable wideband harvester is presented.The proposed harvester can possess arbitrary multiple stability induced by the combined nonlinearities of cantilever-stopper engagement and magnetoelasticity.The harvesting efficiency is enhanced by interwell oscillations and the global amplitude of the harvester is restricted by cantilever-stopper engagement.The formation mechanism of the multi-stability and the associated parameter regions with different magnet configurations are identified.The electromechanical coupling model of the proposed harvester is established to describe its dynamic characteristics.To explore the influence of potential well configurations on multi-stable energy harvesting,the proposed harvesters with four typical potential well configurations are established while its equivalent nonlinear restoring force is experimentally identified.The dynamic characteristics of these four configurations at different levels of harmonic excitation are explored by numerical methods and verified by experiments.Results show that,a multiple-well potential with non-uniform depth and shallower outer wells is much more suitable for the proposed system when the external excitation exceeds a critical intensity in comparison to multiple-well potential with uniform depth,which has a good performance in conventional multi-stable energy harvesters.Furthermore,by enhancing the harvesting efficiency and by restricting the global amplitude of the tip mass,the proposed multi-stable system achieved 6.3 times higher power density than its conventional counterpart.