A squirrel-inspired drone with whole-body morphing

A gliding-mammal-inspired drone for studying stability, agility, and maneuverability through coordinated limb, tail, and membrane morphing.

Citation: Liming Zheng, Alexander van Zuijlen, and Salua Hamaza. “A squirrel-inspired drone with enhanced stability, agility and maneuverability via whole-body morphing.” Nature Communications, 2026.

This project investigates how gliding mammals, especially flying squirrels, coordinate their limbs, tail, and compliant flight membrane. Liming Zheng translated these biological features into a powered aerial robot whose complete aerodynamic shape can change during flight.

The research challenge

Conventional aircraft inherit a fixed balance between stability and manoeuvrability from their geometry. Gliding mammals can alter that balance continuously because their limbs tension and reshape a soft membrane. The central challenge was to build an aircraft that preserves this coupling between actuation, structural deformation, and aerodynamic response.

Robot and morphing architecture

SquirrelDrone uses five actuators to control its forelimbs, hindlimbs, and tail. Six passive ribs support a skin-like membrane, while twin front-mounted propellers provide powered flight. Limb motion changes camber, twist, dihedral, and effective angle of attack across the body. Aerodynamic pressure also deforms the passive ribs, so the final flight shape emerges from both actuation and airflow.

Experimental programme

Liming combined membrane-shape reconstruction, wind-tunnel force and moment measurements, and dynamic tests. Reflective markers recorded how the soft surface changed under aerodynamic loading. Balance measurements quantified lift, drag, and stability derivatives across limb and tail configurations. Tethered open-loop tests then measured roll and pitch responses, followed by pull-up manoeuvres and outdoor flights.

Main findings

• At 12 m/s, the passive ribs moved upward by about 10% to 13% of the local chord.
• Passive deformation increased the lift coefficient by more than 0.1 below 24° angle of attack compared with fixed ribs.
• The passive configuration remained longitudinally statically stable across the tested range, while the fixed-rib configuration was unstable below 10°.
• Differential forelimb and hindlimb actuation produced the strongest roll response, while the hindlimbs and tail supplied strong pitch authority because of their position behind the center of gravity.
• Whole-body morphing changed both aerodynamic forces and moments, enabling the vehicle to trade stability for agility and manoeuvrability in flight.

Why it matters

The work shows that a compliant body does not have to be treated as an uncertain disturbance. Its deformation can improve lift and stability, while active whole-body morphing provides control authority. This gives future morphing aircraft a physical mechanism for adapting their flight characteristics in real time.