Harvesting of ambient floor vibration energy utilizing micro-electrical mechanical devices

Recent advances in device fabrication and energy harvesting technology combined with an increasing need for sustainable energy generation have encouraged the development of the micro-electro-mechanical (MEMS) energy harvesting model for floor vibrations presented herein. By calibrating arrays of MEMS energy harvesters in resonance with floor vibrations, building occupants become sustainable energy sources. Optimization of these harvesters to frequency ranges of floor vibrations, subsequent synchronization of harvester location to occupant flow and improved electromechanical modelingmay result in an efficient, passive power source for low-demand applications independent of external environmental conditions. A model of a floor-harvester system is developed, utilizing ambient floor vibration to excite MEMS energy harvesters via harmonic base translation. These devices then convert the mechanical vibrations to electrical power. Design considerations for piezoelectric-based energy harvesters inspired by MEMS-scale arrays are investigated. Single degree of freedom and distributed beam parameter electromechanical models are employed to predict performance, by optimization of resonant frequencies from measured low-level ambient vibrations. A simplified analytical expression for a frequency correction factor accounting for shear deformation and rotatory inertia effects is derived in terms of fundamental system parameters. Floor and energy harvesting device models are validated by comparison to experimental results and numerical modeling, respectively.