Chaotification as a Means of Broadband Energy Harvesting With Piezoelectric Materials

Abstract

Component miniaturization and reduced power requirements in sensors have enabled growth in the field of lowpower ambient vibration energy harvesting. This work aims to increase bandwidth and power output beyond current techniques by inducing chaotic nonlinear phenomena and applying a lowpower controller based on the method of Ott, Grebogi, and Yorke (OGY) to stabilize a chosen periodic orbit. Previously, researchers used a nonlinear piezomagnetoelastic beam in search of a large amplitude broadband voltage response, but chaos was strictly avoided. These large amplitude responses can deteriorate over time into low energy chaotic oscillations. Including chaos as a desirable property allows small perturbations to alter the behavior of a system dramatically, improving the dynamic response for energy harvesting. The nonlinear piezomagnetoelastic beam element described by a Duffing oscillator is extended to embrace chaotic motion more actively. By driving motion along a chaotic attractor, even single frequency excitation results in a theoretically infinite number of unstable periodic orbits that can be stabilized using small control inputs. The chosen orbit will be accessible from a large range of excitation frequencies and can be dynamically changed in realtime, potentially expanding the bandwidth of operation.