Experimental Evaluation of the Feasibility of Wearable Piezoelectric Energy Harvesting

Technological advances in low power wearable electronics and energy optimization techniques

make motion energy harvesting a viable energy source. However, it has not been

widely adopted due to bulky energy harvester designs that are uncomfortable to wear. This

work addresses this problem by analyzing the feasibility of powering low wearable power

devices using piezoelectric energy generated at the human knee. We start with a novel

mathematical model for estimating the power generated from human knee joint movements.

This thesis’s major contribution is to analyze the feasibility of human motion energy harvesting

and validating this analytical model using a commercially available piezoelectric

module. To this end, we implemented an experimental setup that replicates a human knee.

Then, we performed experiments at different excitation frequencies and amplitudes with

two commercially available Macro Fiber Composite (MFC) modules. These experimental

results are used to validate the analytical model and predict the energy harvested as a function

of the number of steps taken in a day. The model estimates that 13μWcan be generated

on an average while walking with a 4.8% modeling error. The obtained results show that

piezoelectricity is indeed a viable approach for powering low-power wearable devices.