  Perching is a promising solution for a small unmanned aerial vehicle (UAV) to
save energy and extend operation time. This paper proposes a quadrotor that can
perch on planar structures using the ceiling effect. Compared with the existing
work, this perching method does not require any claws, hooks, or adhesive pads,
leading to a simpler system design. This method does not limit the perching by
surface angle or material either. The design of the quadrotor that only uses
its propeller guards for surface contact is presented in this paper. We also
discussed the automatic perching strategy including trajectory generation and
power management. Experiments are conducted to verify that the approach is
practical and the UAV can perch on planes with different angles. Energy
consumption in the perching state is assessed, showing that more than 30% of
power can be saved. Meanwhile, the quadrotor exhibits improved stability while
perching compared to when it is hovering.
