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This paper deals with the aerodynamic modeling of a ducted fan Vertical TakeOff and Landing (VTOL) Unmanned Aerial Vehicle (UAV) and the problem of attitude stabilization when the vehicle is remotely controlled by a human pilot in presence of crosswind. The main aerodynamic elements, which are inherent to the presence of the duct and explain the flight dynamics of this kind of vehicle, are first presented. Then, an attitude control is designed from a linearization of the dynamic model around the hovering flight equilibrium. As the vehicle is axis-symmetric, the pitch and the roll dynamics have a similar expression. For this reason, the presentation is focused on the design of the pitch controller. Similar results can be directly deduced for the roll. Experiments, led on the HoverEye platform designed by Bertin Technologies, show that the proposed attitude control is sufficient to open a large secure flight envelope.

This paper considers the problem of obtaining high quality attitude extraction and gyros bias estimation from typical low cost intertial measurement units for applications in control of unmanned aerial vehiccles. Two different non-linear complementary filters are proposed: Direct complementary filter and Passive non-linear complementary filter. Both filters evolve explicity on the special orthogonal group SO(3) and can be expressed in quaternion form for easy implementation. An extension to the passive ocmplementary filter is proposed to provide adaptive gyro bias estimation.