Sunlight-Driven Continuous Flapping-Wing Motion

Abstract

Light-driven actuators that directly convert light into mechanical work have attracted significant attention due to their wireless advantage and ability to be easily controlled. However, a fundamental impediment to their application is that the continuous motion of light-driven flexible actuators usually requires a periodically switching light source or the coordination of other additional hardware. Here, for the first time, continuous flapping-wing motion under sunlight is realized through the utilization of a simple nanocrystalline metal polymer bilayer structure without the coordination of additional hardware. The light-driven performance can be controlled by adjusting the grain size of the upper nanocrystalline metallic layer or selecting metals with different thermodynamic parameters. The achieved highest frequency of flapping-wing motion is 4.49 Hz, which exceeds the frequency of real butterfly wings, thus informing the further development of sunlight-driven bionic flying animal robotics without external energy consumption. The flapping-wing motion has been used to realize a light-driven whirligig, a light-driven sailboat, and photoelectric energy harvesting. Furthermore, the flexible bilayer actuator features the ability to be driven by light and electricity, low-power actuation, a large deflection, fast actuation speed, long-time stability, strong design ability, and large-area facile fabrication. The bilayer film considered herein represents a simple, general, and effective strategy for preparing photoelectric-driven flexible actuators with target performances and informs the standardization and industrial application of flexible actuators in the future.

Soft Actuators for Soft Robotic Applications: A Review

“…It should be noted that a frequency of 2.7 Hz is enough to achieve a flying motion similar to that of butterflies. [ 209 ]…”

“…Reproduced with permission. [ 209 ] Copyright 2020, ACS. b) Schematic of the fabrication process of the LIG‐based soft actuators.…”

“…It should be noted that a frequency of 2.7 Hz is enough to achieve a flying motion similar to that of butterflies. [209] Inspired by botanical systems where the microstructures are concurrently created and aligned in a single bottom-up process, Deng et al reported self-morphing soft actuators using laserinduced graphene (LIG) structures developed in a bottom-up approach and which resemble the aligned microstructures of plant cellulose fibrils. The LIG structures are used to dictate the shape of the soft actuator, based on LIG layers and a polymer, Figure 12.…”

Bio-inspired life-like motile materials systems: Changing the boundaries between living and technical systems in the Anthropocene

“…The smallest systems are based on liquid crystal elastomers and are only a few millimeters in size (Kohlmeyer and Chen, 2013;Wani et al, 2017). Amongst other systems, these were driven by photo-thermally produced heat (Dong et al, 2020;Lim et al, 2017) or via joule heating (Kim et al, 2014;Lim et al, 2017) (Figure 6b). Furthermore, AVFT systems exist, in which the "trap" closure movements are actuated via magnetism (Esser et al, 2019;Schmied et al, 2017;Zhang et al, 2016) (Figure 6c), electricity (Shahinpoor, 2011;Shahinpoor and Thompson, 1995), pressurized air (Esser et al, 2019;Pal et al, 2020;Temirel et al, 2016;Wang et al, 2020) (Figure 6d), temperature changes (Esser et al, 2019;Riley et al, 2020) (Figure 6b), or hydrogel swelling or shrinking activated via enzymes (Athas et al, 2016) or moisture (Esser et al,.…”

Design optimization and wind tunnel investigation of a flapping system based on the flapping wing trajectories of a beetle's hindwings

“…Miniaturization is an important goal in micro air vehicle (MAV) design and has received increasing attention [1][2][3]. In recent years, insects such as dragonflies [4], fruit flies [2], butterflies [5], and hawkmoths [6] have been used as biological prototypes for insect-like MAVs. Coleoptera (beetles) are also agile natural flyers, with forewings (also called elytra) that are not membranous but rather are thick chitinous protective shields.…”