Engineers at Princeton University and the University of Illinois Urbana-Champaign have developed new insect-scale flying robots using a grasshopper-inspired gliding approach, potentially addressing persistent power limitations in tiny robots.
Research published January 7 in the Journal of the Royal Society Interface indicated that grasshopper-inspired wings could enable miniature robots to alternate between energy-intensive flapping and power-saving gliding. This contrasts with most existing insect-scale flying robots, which mimic bees or flies and rely on constant wing flapping, leading to rapid battery depletion due to high energy demands at small scales.
The collaboration began with field studies of American grasshoppers to analyze their flight mechanics. Researchers focused on the hindwings of Schistocerca americana, noting an accordion-style folding mechanism for retraction during ground mobility and deployment for flight. Aimy Wissa, associate professor of mechanical and aerospace engineering at Princeton and the study’s principal investigator, stated, “Gliding is a mode of cheap flight. When we want to produce thrust, we flap. When we want to conserve energy, we fully deploy the wings and glide.”
The team utilized CT scans to capture grasshopper wing geometry, then converted these scans into 3D-printable designs. They printed model wings, measuring between 2 and 4 inches wide, and tested their aerodynamic performance in a water channel before conducting flight experiments at the Princeton Robotics Laboratory.
Unexpectedly, while natural wing corrugations—sharp ridges—aided lift, smooth wings demonstrated improved gliding efficiency. Wissa suggested that corrugations might have evolved for other functions, such as wing folding or managing steep flight angles. Using advanced motion-capture cameras, researchers observed their grasshopper-inspired gliders performed comparably to actual grasshoppers. Paul Lee, a Princeton graduate student and the paper’s lead author, said the accordion-style wing design offers advantages over other insects, noting, “Dragonfly wings always stick straight out, and butterfly wings can only fold upward, which is limiting.”
The team is developing a system for automatic wing deployment and retraction, aiming to avoid heavy motors. Future research will focus on incorporating corrugations for wing folding while maintaining gliding efficiency and integrating the design with jumping capabilities. Lee stated, “This grasshopper research opens up new possibilities not only for flight, but also for multimodal locomotion.”
