Power harvesting of piezoelectric cantilever beam using flow induced by human walk

• Main Authors: Ssu-Ting TSAI, 蔡絲婷
• Other Authors: 張培仁
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/20664348111751118591

碩士 === 國立臺灣大學 === 應用力學研究所 === 103 === Aging society urges the needs of stand-alone wearable monitoring system in recent years. However, limited life-span of battery and the difficulty to replace it have made the job considerably inconvenient. One desirable solution is to harvest energy from the environment and transfer it into reliable and durable electric power source by transducers. With this in mind, this research expects to develop a power harvesting device supplying electricity for monitoring system in the operational environment. The research utilizes a flexible piezoelectric cantilever beam (Polyvinylidene fluoride, PVDF) with dissymmetric arranged cylindrical bluff body attaching to its free end as a power harvesting unit. The periodical lift force will be generated when the flow passes the free end inducing vibration and also the output voltage of the cantilever beam. A tip displacement can be reached as large as 4 mm under flow speed of 9.8 m/s and the output voltage can be achieved to be 1.18V subjected to an external electrical resistance of 1 MΩ, with the corresponding power of 1.4 μW. Moreover, the research realizes a shoe embedded power harvesting device. The stepping power of walking will push air stream from the outlet of insole into flow channel made of acryl and excite the power harvesting unit placed inside the chamber which eventually scavenges power from the operational environment.