Evaluation of human-scale motion energy harvesting for wearable electronics

We explore the potential of human-scale motion energy harvesting toward enabling self-powered wearable electronic components to avoid the burden of battery replacement and charging in next-generation wireless applications. The focus in this work is piezoelectric transduction for converting human motion into electricity. Specifically, we explore three piezoelectric energy harvesting approaches experimentally and numerically: (1) Direct base excitation of a cantilevered bimorph configuration without/with a tip mass; (2) plucking of a bimorph cantilever using a flexible/nonlinear plectrum; and (3) direct force excitation of a curved unimorph. In all cases, electromechanical models are developed and experimental validations are also presented. Specifically a nonlinear plectrum model is implemented for the plucking energy harvester. Average power outputs are on the order 10-100 uW and can easily exceed mW in certain cases via design optimization.