Modeling and Trajectory Control of a Transitioning Quadrotor Biplane Tailsitter

A comparison study between modeling approaches of a quadrotor biplane tailsitter aircraft is conducted. A blade element theory model with dynamic inflow is used to validate a reduced order model that incorperates a simple interference model for trajectory planning and dynamic simulation. With an appropriate interference model, the predicted power requirement through transition from hover to forward flight drops by 30-45% as the interference velocity reduces the effective angle of attack for the wing. A trajectory generation scheme is developed, which shows the importance of accurate stall modeling for the transition maneuver. Without interference modeling all transition trajectories are expected to violate the installed motor power limit or pass through an excessively stalled wing state (> 60%). The interference model dynamics are used to design a trajectory that avoids stall of the aircraft by adding a vertical climb element to the transition maneuver. A transition controller is linear dynamic inversion transition controller is described for inner loop stability over the entire flight regime.