A flapping-wing robot from Northwestern Polytechnical University uses a movable tail to balance stable cruising with sharp maneuvers. The NPU-Sparrow combines a linkage-driven morphing tail with control over the angle at which its wings meet the oncoming air.
The design addresses a trade-off in small flapping aircraft: a configuration that stays stable in forward flight can resist quick turns, while adding separate actuators for each flight mode increases mechanical and control complexity. The researchers instead coordinate the tail and wing incidence angle, a measure of how the wing is tilted relative to the airflow.
In aerodynamic models and wind-tunnel measurements, the tail changes roles with flight condition. At lower angles of attack, it produces negative lift that helps stabilize the robot’s pitch. Above 13 degrees, it contributes lift instead. The linkage lets the same tail support both regimes without adding a separate actuator for each role.
Outdoor tests showed level flight across a reported speed range of 4.5 to 13.2 meters per second. The prototype reached a peak roll rate of 375 degrees per second and performed loops and barrel rolls.
The results demonstrate a model-guided control strategy on one flapping-wing prototype. Whether it can sustain useful flight times and repeat the maneuvers reliably under varied conditions remains a practical test for future work.
Sources
- Nature Communications: “Wing-tail coordination balances efficient cruising and maneuvering flight in an avian-inspired flapping robot” (24 September 2026), doi:10.1038/s41467-026-78005-x.
- Illustrative photograph, not the robot: Giles Laurent, “Ringed kingfisher flying with a fish”, CC BY-SA 4.0. © Giles Laurent, gileslaurent.com, License CC BY-SA. Image used unchanged.
