University of Minnesota
University Relations
myU OneStop

Go to unit's home.

Home | DTI | 2007–08 funded proposals | William P. Robbins, Rajesh Rajamani, Dan Glumac, Peter Schiller

Initiatives in Digital Technology: 2007–08 Funded Proposals

William P. Robbins, Rajesh Rajamani, Dan Glumac, Peter Schiller

Powering Portable Electronics Using Energy Harvested from Human Locomotion (Walking)

This project will develop methods to significantly improve the output power of piezoelectric inserts in shoes. Such inserts have been previously studied as a way to generate modest amounts of electric energy from walking. Three improvements will be explored in this project. First the piezoelectric PVDF (polyvinylidene fluoride) stave or bender insert placed under the ball of the foot will be replaced with inserts utilizing macrofiber composites which are made of small diameter (200 microns) PZT (lead zirconium titanate) fibers embedded in expoxy. Second , PZT d 13-mode plate inserts located under the heel of the foot will be replaced with d33-mode stack actuators. Third a quasi-resonant rectifier will be used to extract the electrical energy from the inserts in place of the conventional full-wave rectifier. It is estimated that these improvements will increase the output power from the 10 mW level previously measured to approximately 100 mW. This level of power would be useful for recharging the batteries in portable electronics such as PDAs, MPEG music players (IPODs), cell phones, medical devices and sensors ,and other similar devices. A multi-disciplinary team from the University (Electrical Engineering, Mechanical Engineering) and industry (Envoy Medical Corp.) will carry out the research. A successful proof-of-concept demonstration of these improvements in this project will put us in a strong position in seeking future outside funding for this research.