Portable and wearable electric devices are an important part of our life and the energy supply is critical for their functions. Energy harvesting from human motion is a promising solution to provide the energy supply. This paper presents the design, modeling and testing of a vibration energy harvester using a novel half-wave mechanical rectification to enhance the performance of suspended energy harvesting backpack. The proposed half-wave mechanical rectification mechanism uses one set of rack-pinion and a one-way clutch that converts bidirectional vertical oscillation into unidirectional rotation of the generator with nonlinear inertia. As validated by both modelling and bench tests, the proposed half-wave mechanical rectification-based energy harvesting system can obtain about twofold average output power as the previous full-wave mechanical rectification system in the desired dominant excitation frequency and also maintains larger output power in the target frequency range. The influences of external resistance, human walking speed, and payload mass are also studied to comprehensively characterize the performance and robustness of the proposed design. Treadmill tests on different human subjects demonstrate an average power range of 3.3–5.1 W under a walking speed of 4.8 km/h (3 mph) with a 13.6 kg (30 lbs.) payload. Experimental results indicate that the proposed suspended energy harvesting backpack could continuously generate an amount of electricity suitable for powering portable and wearable electronic devices, which can be applied to the military, field workers, outdoor enthusiasts and disaster relief scenarios.

便携式和可穿戴电子设备是我们生活中的重要组成部分，能源供应对其功能至关重要。从人体运动中收集能量是提供能量供应的有希望的解决方案。本文介绍了使用新型半波机械整流技术来增强悬挂式能量收集背包性能的振动能量收集器的设计，建模和测试。提出的半波机械整流机构使用一组齿条小齿轮和单向离合器，该单向离合器将双向垂直振荡转换为具有非线性惯性的发电机的单向旋转。经过建模和基准测试的验证，所提出的基于半波机械整流的能量收集系统在所需的主导激励频率下可以获得大约两倍于以前的全波机械整流系统的平均输出功率，并且还能在目标频率范围内保持较大的输出功率。还研究了外部阻力，人体步行速度和有效载荷质量的影响，以全面表征所提出设计的性能和鲁棒性。在不同人体上的跑步机测试表明，在4.8 km / h（3 mph）的步行速度和13.6 kg（30 lbs）的有效负载下，平均功率范围为3.3–5.1W。实验结果表明，提出的悬挂式能量收集背包可以连续产生一定数量的电能，适合为便携式和可穿戴电子设备供电，