Transition Analysis and Practical Flight Control for Ducted Fan Fixed-Wing Aerial Robot: Level Path Flight Mode Transition

For agile fixed-wing aerial robots, the vertical/horizontal flight mode transition is a fundamental requirement for high maneuverability. This letter focuses on a challenging implementation in which the aircraft conducts the transitional flight at fixed altitude along a straight path. Implemented on a small ducted fan fixed-wing, we propose a transition-corridor-based control strategy to conduct the flight transition neatly. The transition corridor is described as a region comprising all the admissible flight velocities, accelerations and attitudes, bounded by the capacity of both the propulsion and control system of the vehicle. By planning the transition trajectory in obedience with the identified transition corridor, as well as adopting a unified full envelope flight control scheme, the ducted fan fixed-wing successfully accomplishes the practical transitional flight. Experimental results are satisfactory in both flight mode transition and altitude stabilization.