Multifunctional Unmanned Aerial Vehicle Wing Spar for Low-Power Generation and Storage

摘要

This paper presents the investigation of a multifunctional energy harvesting and energy-storage wing spar for unmanned aerial vehicles. Multifunctional material systems combine several functionalities into a single device in order to increase performance while limiting mass and volume. Multifunctional energy harvesting can be used to provide power to remote low-power sensors on unmanned aerial vehicles, where the added weight or volume of conventional harvesting designs can hinder flight performance. In this paper, a prototype self-charging wing spar containing embedded piezoelectric and battery elements is modeled, fabricated, and tested to evaluate its energy harvesting and storage performance. A coupled electromechanical model based on the assumed modes method is developed to predict the vibration response and voltage response of a cantilevered wing spar excited under harmonic base excitation. Experiments are performed on a representative self-charging wing spar, and the results are used to verify the electromechanical model. The power-generation performance of the self-charging wing spar is investigated in detail for harmonic excitation in clamped-free boundary conditions. Experiments are also conducted to demonstrate the ability of the wing spar to simultaneously harvest and store electrical energy in a multifunctional manner. It is shown that, for an input base acceleration level of ±0.25 g at 28.4 Hz at the base of the structure, 1.5 mW of regulated dc power is delivered from the piezoelectric layers to the thin-film battery, resulting in a stored capacity of 0.362 mAh in 1h.