The structures of exposed propellers of multi-rotors may be damaged in collision and cause damage to bystanders. A new prototype UAV solves this problem, which imitates the practice of blowfish. When feeling the threat of being too close to other animals, the puffer will inflate like a balloon, making itself bigger. PufferBot, a “PufferBot” unmanned aerial vehicle designed by the engineering team of the University of Colorado at Boulder, also adopted a similar method.
In a conventional flight, an array consisting of linked and pre-tightened plastic rod is folded up, closely sticking to the fuselage of the quadrocopter. However, when proximity sensor of the UAV detects that someone (or something else) is too close, these poles will push outward. This will lead to the expansion of the array into a shield surrounding the UAV body.