  Autonomous flight of flapping-wing robots is a major challenge for robot
perception. Most of the previous sense-and-avoid works have studied the problem
of obstacle avoidance for flapping-wing robots considering only static
obstacles. This paper presents a fully onboard dynamic sense-and-avoid scheme
for large-scale ornithopters using event cameras. These sensors trigger pixel
information due to changes of illumination in the scene such as those produced
by dynamic objects. The method performs event-by-event processing in low-cost
hardware such as those onboard small aerial vehicles. The proposed scheme
detects obstacles and evaluates possible collisions with the robot body. The
onboard controller actuates over the horizontal and vertical tail deflections
to execute the avoidance maneuver. The scheme is validated in both indoor and
outdoor scenarios using obstacles of different shapes and sizes. To the best of
the authors' knowledge, this is the first event-based method for dynamic
obstacle avoidance in a flapping-wing robot.
