Abstract—This paper presents a robust position controller
for a tilt-wing quadrotor to track desired trajectories under
external wind and aerodynamic disturbances. Wind effects
are modeled using Dryden model and are included in the
dynamic model of the vehicle. Robust position control is
achieved by introducing a disturbance observer which estimates
the total disturbance acting on the system. In the design of
the disturbance observer, the nonlinear terms which appear
in the dynamics of the aerial vehicle are also treated as
disturbances and included in the total disturbance. Utilization
of the disturbance observer implies a linear model with nominal
parameters. Since the resulting dynamics are linear, only PID
type simple controllers are designed for position and attitude
control. Simulations and experimental results show that the
performance of the observer based position control system is
quite satisfactory.