An untethered sub-gram flapping-wing flight system achieves sustained self-stabilizing and controllable flight

Insect-scale flapping-wing micro aerial vehicles (FWMAVs) offer great potential for applications like search and rescue, but face severe power and payload constraints at sub-gram scales, precluding sustained untethered flight. This study presents a cross-shaped four-piezoelectric-drive V-wing micro aerial vehicle (FVW-Fly), weighing 389 mg with a 6.8 cm wingspan, which achieves a lift-to-weight ratio of 4.75. Waveform modulation boosts the driving efficiency of a 173 mg circuit to 45%, while mechanical self-stabilization enhances flight stability. Integrated with a 350 mg battery, the 984 mg system achieves the first untethered, sustained, stable flight for a sub-gram FWMAV. Its maximum flight altitude exceeds 10 meters, and the low-power single-cycle continuous flight time exceeds 240 seconds, demonstrating untethered controlled altitude and disturbance resilience flight, marking a groundbreaking milestone.