A wing inspired by those of birds and bats can overcome collisions with obstacles, and might allow the development of flying robots that have improved energy efficiency.

Credit: IOP Publishing

Amanda Stowers and David Lentink of Stanford University, California, built a robotic flapping wing consisting of an 'arm' attached to the body and a hinged 'hand' attached to that. The design naturally unfolds when the wing beats during flight. Modelling revealed that flapping generates acceleration, unfolding the wing.

The researchers showed in the lab that when the wing's hand hits a branch (pictured, left), it compensates by furling in (middle) and then unfurling (right), surviving impacts of up to 5 metres per second. This design could help future flapping robots to deal with tricky flight paths without the need for complicated algorithms, say the authors, because collisions could be survived rather than avoided.

Bioinspir. Biomim. 10, 025001 (2015)