Nature-inspired in-flight foldable rotorcraft.

In this paper, we introduce a novel rotary wing platform, that can fold and expand its wings during flight. The design of the rotorcraft is based on the monocopter platform, which are inspired from the flight of Samara seeds. The wings are constructed by applying origami technique to fold them in flight. Two configurations are presented where the folding of the wing is based on active and passive folding mechanisms. The two configurations can reduce their overall length by approximately 39% and 65% while in flight. A cyclic controller is implemented for controlling the translational motion, where the direction is controlled by pulsing the motors at specific instance during each cycle of rotation. We have presented experimental results to prove the control of our platform in different modes while in flight. The presented platforms enhances the practical uses of monocopter platform by providing it with the ability to reduce its footprint while in flight actively, and by allowing them to dive through the air without any additional actuator.