Chaotification as a Means of Broadband Energy Harvesting With Piezoelectric Materials

Component miniaturization and reduced power requirements in sensors have enabled growth in the field of low-power ambient vibration energy harvesting. This work aims to increase bandwidth and power output beyond current techniques by inducing chaotic nonlinear phenomena and applying a low-power 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 real-time, potentially expanding the bandwidth of operation.