Disturbance Observer Based Hovering Control of Quadrotor Tail-Sitter VTOL UAVs Using H∞ Synthesis
Hybrid VTOL UAVs such as tail-sitters allow several key maneuvers such as vertical takeoff, landing, and hovering while at the same time maintaining superior aerodynamic efficiency at level flight. However, the large wing area of a tail-sitter at hovering makes it rather sensitive to the cross wind.