Researchers from Swiss research institute EPFL have developed a crash resistant quad-copter design modelled on the dual stiffness properties seen in insect wings.
Insect wings are composed of sections made of cuticle, a stiff material that takes the load bearing portion of the wing, connected with flexible joints made of the protein resilin that have evolved to be shock absorbent and compliant. These two factors together allow insect wings to be both strong and load bearing, and compliant and durable.
The team’s drone is made of a central case and a thin fibreglass external frame with four arms held together by four magnetic joints.
As this fibreglass frame is only 0.3mm thick, it is soft and flexible, making it able to withstand collisions without permanent deformation.
The four magnetic joints connect the frame to the central case and rigidly hold the frame in place during flight. During a collision these magnetic joints break apart, meaning that the drone transitions to a soft state where the frame becomes disengaged and can safely deform without damaging itself or the inner core.
Soft elastic bands ensure that the frame is held close enough in place that the magnets snap back after the collision, allowing the frame to realign and thus ensuring that the drone is once again ready to fly.