Piezoelectric Energy Harvesting from the Thorax Vibration of Freely Flying Bees

Abstract

Insect cyborgs have been proposed for application in future rescue operations, environmental monitoring, and hazardous area surveys. An energy harvester for insect carrying is critical to the long-lasting life of insect cyborgs, and designing an energy harvester with superior energy output within the load capacity of tiny flying insects is very important. In this study, we measured the thorax vibration frequency of bees during loaded flight conditions. We propose a piezoelectric vibration energy harvester for bees that has a mass of only 46 mg and can achieve maximum effective output voltage and energy density of 5.66 V and 1.27 mW/cm³, respectively. The harvester has no marked effect on the bees' normal movement, which is verified by experiments of mounting the harvester on bees. These results indicate that the proposed harvester is expected to realize a self-power supply of tiny insect cyborgs.

Fig. 1.

Experiment of bees flying with load masses. (A) Schematic diagram of the overall experimental setup. (B) The bees’ flight experiment box. (C) Photos of the experimental setup. (D) Schematic of the bees’ loading method and masses. CMOS, complementary metal–oxide–semiconductor; LED, light-emitting diode.

Fig. 2.

Design, fabrication, and test of the piezoelectric energy harvester (PEH). (A) Schematic diagram of the vibrational energy harvesting setup used in this study. (B) Schematic diagram of the exploded view of the PEH. (C) The PEH. (D) Schematic diagram and (E) photograph of the experimental setup used for evaluating the output performance of the PEH. PVDF, polyvinylidene fluoride; AMP, amplifier; VF, voltage follower; GPIB, General-Purpose Interface Bus.

Fig. 3.

A bee’s flights under different load conditions. (A) A bee flying under the load mass was photographed by a high-speed CMOS camera. (B) Imbalance rate ($I_r$) under different load masses. (C) The frequency distribution of the bee wing flapping with no load mass. (D) The concentrated frequency interval of bees under different load masses.

Fig. 4.

The vibration characteristics and electrical output results of the PEH. (A) Schematic diagram of bee wing flapping and principle of the simulation experiment. (B) A photo of the PEH fixed on the exciter. (C) Distribution of PEH’s displacement and surface potential obtained by Comsol Multiphysics. (D) Damping test method and results of the PEH.

Fig. 5.

The PEH performance. (A and B) The PEH output at different resistances. (C and D) The PEH output at different frequencies. (E) The PEH voltage at different exciting acceleration values. (F) Power and displacement of the PEH at different exciting acceleration values. (G) Comparison of the proposed PEH with other insect vibration energy harvesters in terms of mass. The illustration is a photo of PEH weighing. (H) Comparison of the PEH’s output performance with the performances of other insect vibration energy harvesters. TR’s, Timothy Reissman’s; EEA, Ethem Erkan Aktakka’s; JS’s, Jake Shearwood’s.