The complex nonlinear dynamics of tilt-rotor aircraft has consistently limited their applications due to substantial challenges in transition flight safety. The aerodynamic characteristics of tilt-rotor aircraft wings are studied in this paper. Systematic wind tunnel tests focused on the coupling propeller, angle of attack, aileron, and flap are first conducted. Important aerodynamic forces, moments, and coefficients are derived through the distributed engagement of multiple measuring balances. The results show that although the amplitudes of the aerodynamic coefficients of the wings are affected by the nacelle and propeller slipstream, their evolution trends are similar to those of a basic airfoil. Based on this finding, a simple but effective aerodynamic characterization method is proposed based on wind tunnel test data, which achieves a straightforward polynomial approximation of the aerodynamic coefficients under high angles of attack in full transition processes. This work provides a solid foundation for future control law design and the simulation of tilt-rotor aircraft.

The continuous configuration changes and velocity variations of tilt-rotor UAVs during the transition phase pose significant challenges to flight safety. Hence, the transition phase trajectory must be specially designed. The transition corridor is an effective means of characterizing the controllable flight state and safe flight boundary of the tilt-rotor UAV transition phase. However, the conventional transition corridor is established based on the trim criterion, which cannot fully characterize the dynamic characteristics of the transition phase, resulting in deviations in the delineation of the flight boundary. This paper proposes a method that characterizes the dynamic transition corridor of a tilt-rotor UAV during the transition phase. A three-dimensional transition corridor considering the nacelle angle, velocity, and angle of attack is established by relaxing the force constraints and introducing angle of attack variables, allowing the dynamic characteristics of acceleration and deceleration in the transition phase to be characterized. On this basis, a transition trajectory optimization method based on the three-dimensional dynamic transition corridor is established using pigeon-inspired optimization with an objective that considers the smooth transition of tilt-rotor UAVs. Numerical simulations show that, compared with the transition trajectory obtained using a two-dimensional transition corridor, the proposed method ensures smoother changes in the velocity, nacelle angle, and expected angle of attack during the transition phase, resulting in stronger engineering practicality.

Tilt-rotor uncrewed aerial vehicles (UAVs) combine vertical takeoff and landing capability with efficient, long-endurance forward flight. However, transition maneuvers between hover and cruise are particularly challenging due to complex aerodynamic coupling. This article proposes a control method that enables stable flight across the full range of nacelle tilt angles, treating transition not merely as a transient phase but as a robust and controllable flight regime. A velocity-based attitude compensation system combined with a control augmentation strategy is developed to suppress pitching moments caused by longitudinal asymmetry. Additionally, a linear fade-in and fade-out actuator weight optimization strategy is introduced to maximize transition control capability while considering control efficiency and coupling constraints. On this basis, a weighted pseudoinverse control allocation strategy is employed to achieve smooth and accurate actuator coordination in transition flights. Extensive flight experiments are conducted on a newly developed tilt-rotor UAV equipped with tiltable outer wings and inward-inclined tail propellers. The results demonstrate that the proposed method enables stable flight across all nacelle tilt angles and flight speeds, representing a significant advancement in improving the maneuverability of tilt-rotor UAVs.