Piezoelectric-based sole energy harvester for capturing energy from human walking

• Published in: Smart materials and structures Vol. 34; no. 7; pp. 75004 - 75016
• Main Authors: Liao, Haisu, Wang, Yidi, Ren, Zhongliang, Wu, Xinyu, Gao, Fei
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.07.2025
• Subjects: energy harvesting; human foot; human gait; piezoelectric; sole
• ISSN: 0964-1726; 1361-665X
• DOI: 10.1088/1361-665X/ade751

Addressing the challenge of sustainable power for portable and wearable electronics, researchers proposed capturing biomechanical energy from human motion to generate electricity. This paper proposed and developed a piezoelectric-based sole energy harvester for scavenging energy from human walking. Specifically, a cam PZT stacks mechanism was designed to generate electricity during the heel strike. The cam can transform the vertical ground reaction force (GRF) to the horizontal force such that the PZT stacks can be deformed. Then, a compliant beam was exploited to reduce the tangential force acting on the PZT stacks to avoid fracture. In addition, a flexible PZT bending plate was exploited to capture biomechanical energy during the late stance phase. The PZT bending plate will be bent by the forefoot in this state. A prototype of the wearable device was developed and tested when the subject walked on a treadmill. Experimental results show the harvester’s average power output can reach 4.71 mW at 4 km h −1 . With the walking speed increasing to 6 km h −1 , the average output power could reach 7.64 mW. In addition, to investigate the effects of the harvester on the subject comprehensively, the gait and GRF for the subject when walking with and without the harvester are measured and compared.