Longitudinal leveling analysis and transition corridor study for tilt-rotor UAVs

Tilt-rotor UAVs have the compound advantages of agile vertical takeoff and landing and high range time cruise, but also have the technical challenges of complex maneuver distribution and difficult flight control in transition mode. In this paper, a transition corridor calculation method based on steady-state leveling conditions for tilt-rotor UAVs is proposed, and the quantitative modeling and influencing factors of the transition corridor are investigated. First, a quadrotor tiltrotor UAV model is introduced, and then a longitudinal three-degree-of-freedom dynamics model is established. The transition corridor is defined as a safe velocity interval that satisfies the balance of force and moment under different rotor tilt angles. By introducing the least squares iterative algorithm to solve the constrained optimization problem containing parameters such as angle of attack, thrust distribution, rudder deflection, etc., the numerical computation flow of the transition corridor is constructed. In turn, the parameter sensitivity analysis is completed. The results of this paper provide a theoretical basis for the design of the transition control law and the optimization of the overall parameters of the tilt-rotor UAV. Future research can further improve the corridor’s robustness by combining the dynamic disturbance analysis and intelligent control strategy.