Automated tuning of a piezoelectric power harvesting cantilever beam via the application of an axial load

Abstract

This thesis deals with automatic tuning of piezoelectric power harvesters. A prototype was constructed to verify the effect of the application of an axial load on a cantilever beam and the effectiveness of increasing the power harvested from a piezoelectric beam via axial loading. It was shown, experimentally, that the natural frequency of a piezoelectric beam harvester can be changed over a range of 25Hz. From the experimental results it was shown that the power can increase up to seven times when tuned in comparison to unturned. Computer simulations were used to demonstrate a closed loop tuning system’s ability to apply an axial load effectively onto a piezoelectric cantilever beam in response to ambient vibrations. The closed loop tuning system is a viable option for tuning and can lead to increased power when applying the axial load suggested by the tuning system.