Development of Plucked Piezoelectric Energy Harvesting From Human’s Upper Limb Motion

This paper presents the design, modeling, and implementation of a plucked piezoelectric energy harvester (PEH) optimized for human elbow motion. The proposed system leverages the advantages of upper-limb biomechanics, particularly elbow flexion during walking, to generate electrical energy suitable for powering wearable electronics. A compact bimorph PZT-based PEH was selected and integrated with a mechanical plucking mechanism to enable frequency up-conversion from low-frequency body motion to high-frequency piezoelectric vibration. An electromechanical model predicting the electrical output and energy harvesting performance of a plucked PEH system was developed using Hamilton’s Principle and validated through experiments, showing strong agreement in voltage response and energy output. Implemented in MATLAB/Simulink, the model also served as a design tool for parametric optimization, allowing efficient tuning of system parameters prior to prototyping. Furthermore, parameter optimization through experimental tests identified a plucking distance of 0.16 mm and a load resistance of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$800\Omega $ </tex-math></inline-formula> as optimal for the decided bimorph PZT in energy harvesting. The developed prototype successfully demonstrated repeatable energy generation ranging from 22–<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$33~\mu $ </tex-math></inline-formula> J per elbow movement cycle under simulated motion. This work offers a validated framework for future development of energy-autonomous wearable devices that are lightweight, compact, and ergonomically compatible.