一种准零刚度采集器的宽频振动能回收特性分析

Analysis of wide frequency vibration energy recovery characteristics of quasi-zero-stiffness harvester

为了拓宽振动能量采集器的频率带宽,给出一个准零刚度振动能量采集器,研究了该采集器的收集性能.该采集器由两个倾斜的线性弹簧和一个竖直的线性弹簧组成,两个倾斜的弹簧具有snap-through型负刚度特性,竖直的弹簧为线性刚度.改变竖直弹簧的刚度,采集器在平衡位置具有准零刚度的特征.基于电磁感应现象,建立采集器的机电耦合控制方程,利用谐波平衡法,求解采集器的动力学响应.计算发现采集器的幅频响应曲线具有5个解的双跳跃现象,先向左弯曲的软特性,再向右弯曲的硬特性.通过和相应线性采集器比较,发现该采集器频率带宽可以增加3.56倍,比等效线性采集器增加2.87倍.讨论了采集器参数对频率带宽的影响,数值结果验证了近似解析方法的正确性,为振动能量采集器的设计提供了一个新方案,为振动能量采集技术的研究提供了理论支撑.

A novel vibratory energy harvester with quasi-zero-stiffness which has the potential of significantly increasing the steady-state bandwidth is proposed.An electromagnetic device is typically composed of two oblique linear springs with snap-through nonlinearity which produced negative stiffness characteristic and a vertical spring with positive stiffness feature.The quasi-zero-stiffness characteristic of the system is presented by properly designing the parameters.The governing equation of the electromechanical coupling system is established.The harmonic balance method is applied to derive the amplitude-frequency response relationships of the displacement and the electric current.It is found that the amplitude-frequency response curves have double-jumping phenomenon,bending first to the left and then to the right.Besides,five steady-state solutions of the frequency-response equation can exist.The performances of the presented energy harvester and the linear stiffness system are compared.Results demonstrate bandwidth 2.87 times higher than that of the equivalent linear one and 3.56 times higher than that of the positive stiffness linear one.The influence of the system parameters on the displacement,the electric current and the power are also discussed.The approximate analytical outcomes are supported by the numerical results.This paper provides a new scheme and theory for vibratory energy harvesting.