  This paper presents a geometric adaptive control scheme for a quadrotor
unmanned aerial vehicle, where the effects of unknown, unstructured
disturbances are mitigated by a multilayer neural network that is adjusted
online. The stability of the proposed controller is analyzed with Lyapunov
stability theory on the special Euclidean group, and it is shown that the
tracking errors are uniformly ultimately bounded with an ultimate bound that
can be abridged arbitrarily. A mathematical model of wind disturbance on the
quadrotor dynamics is presented, and it is shown that the proposed adaptive
controller is capable of rejecting the effects of wind disturbances
successfully. These are illustrated by numerical examples.
