Nonlinear dynamic analysis of a piezoelectric-electromagnetic harvester driven by human cycling motion: theoretical modeling and on-body experimental validation

Research on human energy harvesting devices primarily focuses on capturing the biomechanical energy generated by physiological movements, aiming to provide sustainable power for implanted medical devices, wearable electronics, and other applications. In this paper, a piezoelectric-electromagnetic hybrid energy harvester is designed to convert energy through the swinging motion of the human hip joint and external stimulation of the structure itself. Initially, the movement of the human body while cycling sports is analyzed, followed by a brief introduction to the structure and principles of the energy harvester. The nonlinear dynamic equation of the energy harvest model is established based on the Lagrange equation. Numerical simulations of the bias magnetic field within the structure are conducted, and the effects of various structural parameters on system response are analyzed. A theoretical model of mutual coupling of multiple force fields is established. The mathematical model is validated through experiments. From the results of the human body-worn test during running, it can be concluded that the effective voltage of a single group of cantilever beams can reach 5.91 V under the influence of multi-field coupling excitation, demonstrating that the designed structure exhibits a commendable energy collection effect.