Physics Practical Magic

Engineers built a drone with bendy arms that steers by literally morphing its own body while it's in mid-air.

April 2, 2026

Original Paper

The QuadSoft: Design, Construction, and Experimental Validation of a Soft and Actuated Quadrotor

Rodolfo Verdin, Hugo Moreno, Mark W. Spong, Gerardo Flores

arXiv · 2604.00496

The Takeaway

Most drones are rigid structures that rely entirely on spinning their propellers at different speeds to move. This 'soft' quadrotor uses tendon-driven arms that can curve and flex like a living creature, allowing it to change its aerodynamic profile and maneuver in ways that traditional, stiff drones cannot.

From the abstract

This paper presents QuadSoft, a novel fully actuated quadrotor equipped with continuous-curvature, tendon-driven soft robotic arms. The design combines a semi-rigid central frame with flexible arms, enabling controlled structural reconfiguration during flight without altering the propeller layout. Unlike existing soft aerial platforms that rely on discrete bending joints, QuadSoft utilizes a continuum deformation approach to modulate arm curvature, actively adjusting its thrust vector and aerody