Ultrafast elastocapillary fans control agile maneuvering in ripple bugs and robots

• 成果类型: Article
• 署名作者: Ortega-Jimenez, Victor M.; Kim, Dongjin; Kumar, Sunny; Kim, Changhwan; Koh, Je-Sung; Bhamla, Saad
• 署名单位: University of California System; University of California Berkeley; University of Maine System; University of Maine Orono; University System of Georgia; Georgia Institute of Technology; Ajou University
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-9303
• DOI: 10.1126/science.adv2792
• 发表日期: 2025-08-21
• 页码: 811-817
• 关键词: aquatic turning performance; whirligig beetle; water striders; walking; maneuverability; insect; lift

摘要

Rhagovelia ripple bugs use specialized middle-leg fans with a flat-ribbon architecture to navigate the surfaces of fast-moving streams. We show that the fan's directional stiffness enables fast, passive elastocapillary morphing, independent of muscle input. This flat-ribbon fan balances collapsibility during leg recovery with rigidity during drag-based propulsion, enabling full-body 96 degrees turns in 50 milliseconds, with forward speeds of up to 120 body lengths per second-on par with fruit fly saccades in air. Drawing from this morphofunctional architecture, we engineered a 1-milligram elastocapillary fan integrated into an insect-scale robot. Experiments with both insects and robots confirmed that self-morphing fans improve thrust, braking, and maneuverability. Our findings link fan microstructure to controlled interfacial propulsion and establish design principles for compact, elastocapillary actuators in agile aquatic microrobots.