Linear cantilevered piezoelectric energy harvesters do not typically operate efficiently through a large span of excitation frequencies. Beam theory dictates optimum displacement at resonance excitation; however, typical environments evolve and vary over time with no clear dominant frequency. Nonlinear, non-resonant harvesting techniques have been implemented, but none so far have embraced chaotic behavior as a desirable property of the system. This work aims to benefit from chaotic phenomena by stabilizing high energy periodic orbits located within a chaotic attractor to improve operating bandwidth. Delay coordinate embedding is used to reconstruct the system states from a single time series measurement of displacement. Orbit selection, local linearization, and control perturbation are all computed from the single time series independent of an explicit system model. Although chaos in non-autonomous systems is typically associated with harmonic inputs, chaotic attractor motion can also exist throughout other excitation sources. Accelerometer data from inside a commercial vehicle and a stochastic excitation signal are used to illustrate the existence of chaos in dynamic environments, allowing such environments to be likely candidates for the proposed bandwidth improving energy harvesting technique.

Date Published: 2 April 2015
PDF: 10 pages
Proc. SPIE 9431, Active and Passive Smart Structures and Integrated Systems 2015, 94310O (2 April 2015); doi: 10.1117/12.2084048

Published in SPIE Proceedings Vol. 9431:
Active and Passive Smart Structures and Integrated Systems 2015
Wei-Hsin Liao, Editor(s)