设计了一种安装在鞋上的压电俘能器(PEH), 用于收集人体行走时产生的能量。该俘能器由4根压电悬臂梁和1个弹簧-质量系统组成。弹簧-质量系统能够感知沿径骨轴的加速度激励, 并通过磁耦合驱动压电梁振动从而发电。文中通过拟合实验数据获得加速度信号表达式; 然后, 建立仿真模型, 对俘能器的发电性能进行了仿真分析。最后, 加工了实验样机, 并实验测试了俘能器的发电性能。结果表明, 当受到沿胫骨方向的激励时, 压电梁在一个步态周期内可被弹簧-质量系统激励多次从而产生多个峰值电压; 受到沿胫骨和脚面两个方向激励时, 压电梁的发电性能比只受到单一方向激励时好。当步行速度为2~8 km/h时, 每根压电梁的峰值电压可达到10 V。该俘能器能够从人体行走的超低频运动中收集能量, 并能够同时收集两个方向的加速度能量, 提高了压电梁的发电性能。

A shoe-mounted piezoelectric energy harvester was designed to collecting energy from human walking. This energy harvester comprises of four piezoelectric cantilever beams magnetically coupled with a spring-mass system. The spring-quality system could sense the acceleration excitation along a radial bone shaft and generate electricity through the magnetic coupling driving a piezoelectric element. The expression of acceleration signals was obtained by fitting the experimental data. And then, a simulation model was established to simulate the power generation performance of the energy harvester. Finally, a prototype was also fabricated and its performance was verified by an experimental test. The results indicate that the four beams could be triggered several times by the spring-mass system within one step when the energy harvester is excited by the acceleration along the tibial axis, and several piezoelectric beam voltage outputs could be obtained. Furthermore, the power-generating capacity of the piezoelectric beam excited by the coupled accelerations is always better than that excited by the single direction acceleration. When walking speed ranges from 2 km/h to 8 km/h, the peak voltage output from each beam is as large as 10 V. The piezoelectric energy harvester collects the energy from human walking in low frequency and the superposition of voltage outputs generated by accelerations comes from two orthogonal directions, so that the power-generating capacity is improved greatly.