  Event cameras are a promising candidate to enable high speed vision-based
control due to their low sensor latency and high temporal resolution. However,
purely event-based feedback has yet to be used in the control of drones. In
this work, a first step towards implementing low-latency high-bandwidth control
of quadrotors using event cameras is taken. In particular, this paper addresses
the problem of one-dimensional attitude tracking using a dualcopter platform
equipped with an event camera. The event-based state estimation consists of a
modified Hough transform algorithm combined with a Kalman filter that outputs
the roll angle and angular velocity of the dualcopter relative to a horizon
marked by a black-and-white disk. The estimated state is processed by a
proportional-derivative attitude control law that computes the rotor thrusts
required to track the desired attitude. The proposed attitude tracking scheme
shows promising results of event-camera-driven closed loop control: the state
estimator performs with an update rate of 1 kHz and a latency determined to be
12 ms, enabling attitude tracking at speeds of over 1600 deg/s.
