  Flying robots are usually rather delicate, and require protective enclosures
when facing the risk of collision. High complexity and reduced payload are
recurrent problems with collision-tolerant flying robots. Inspired by
arthropods' exoskeletons, we design a simple, easily manufactured, semi-rigid
structure with flexible joints that can withstand high-velocity impacts. With
an exoskeleton, the protective shell becomes part of the main robot structure,
thereby minimizing its loss in payload capacity. Our design is simple to build
and customize using cheap components and consumer-grade 3D printers. Our
results show we can build a sub-250g, autonomous quadcopter with visual
navigation that can survive multiple collisions at speeds up to 7m/s that is
also suitable for automated battery swapping, and with enough computing power
to run deep neural network models. This structure makes for an ideal platform
for high-risk activities (such as flying in a cluttered environment or
reinforcement learning training) without damage to the hardware or the
environment.
