A tri-stable energy harvester in rotational motion: Modeling, theoretical analyses and experiments

This paper originally investigates the performance of a tri-stable piezoelectric energy harvester (TPEH) in rotational motion, aiming to solve the challenging issue of power supply for wireless sensors. Based on the Lagrange equation, the related theoretical model with the consideration of the effect of rotational motion is originally derived to describe its dynamic response and energy harvesting performance. In addition, the perturbation method is used to theoretically describe the TPEH for the oscillations around both non-zero and zero stable equilibrium positions. The numerical simulations and case studies are carried out to investigate the influence of the K_c coefficient on the dynamic response of the TPEH. More importantly, the corresponding experiments under different constant rotational speeds are performed to validate the energy harvesting enhancement of the presented TPEH and the accuracy of its theoretical model. It is experimentally verified that the TPEH can efficiently harvest energy in the wide rotational speed range (240–440 rpm), and the proposed theoretical model is suitable for the TPEH. Overall, the energy harvesting enhancement of the TPEH in rotational motion are verified, and the accuracy of the presented theoretical model is also experimentally validated.