New drone design uses flexible frame to survive collisions

Researchers at ETH Zürich have developed a drone prototype, known as FlexiQuad, capable of surviving head-on collisions by utilizing a flexible, hollow, ring-shaped frame. The design allows the drone to absorb impact energy, enabling it to continue flying after hitting obstacles that would typically damage traditional quadcopters.

The project was led by engineer Luca Girardi and Stefano Mintchev, a professor of Agricultural Robotics at the University of Bonn. The team drew inspiration from the wings of birds and insects to implement a concept called anisotropic stiffness. This allows the drone's frame to flex laterally to withstand impacts while maintaining vertical rigidity to support flight thrust.

In laboratory testing, the FlexiQuad demonstrated the ability to withstand head-on collisions at speeds of approximately 25 km/h without sustaining damage. Despite its flexible structure, the prototype can reach flight speeds of up to 80 km/h. Additionally, the drone is designed to be portable, capable of folding to fit into a medium-sized suitcase, and has shown it can carry payloads heavier than its own weight.

The invention has been nominated for the 2026 ETH Zürich Spark Award, and a patent application has been filed. While the prototype has performed well in controlled laboratory environments, the researchers noted that further development is necessary to improve obstacle perception and autonomous navigation for use outside of the lab.