Tilt-rotor unmanned aerial vehicles combine the advantages of multirotor and fixed-wing aircraft, offering features like rapid takeoff and landing, extended endurance, and wide flight conditions. This article provides a summary of the design, modeling, and control of a composite tilt-rotor. During modeling process, aerodynamic modeling was performed on the tilting and non-tilting parts based on the subcomponent modeling method, and CFD simulation analysis was conducted on the entire unmanned aerial vehicle to obtain its accurate aerodynamic characteristics. In the process of modeling the motor propeller, the reduction of motor thrust and torque due to forward flow and tilt angle velocity is thoroughly examined, which is usually ignored in most tilt UAV propeller models. In the controller design, this paper proposes a fusion ADRC control strategy suitable for vertical takeoff and landing of this type of tiltrotor. The control system framework is built using Simulink, and the control algorithm’s efficiency has been verified through simulation testing. Through the proposed control scheme, it is possible for the composite tiltrotor unmanned aerial vehicle to smoothly transition between multirotor and fixed-wing flight modes.

A robust controller for the waypoint tracking of a quadrotor unmanned aerial vehicle (UAV) is proposed in this paper, in which position control and attitude control are effectively decoupled. Model predictive control (MPC) is employed in the position controller. The constraints of motors are imposed on the state and input variables of the optimization equation. This design effectively mitigates the nonlinearity of the attitude loop and enhances the planning efficiency of the position controller. The attitude controller is designed using a nonlinear and robust control law based on $SO(3)$ space, which enables continuous control on the $SO(3)$ manifold. By extending the differential flatness of the quadrotor-UAV to the angular acceleration level, the mapping of the control reference from the position controller to the attitude controller is achieved. Simulations are carried out to demonstrate the capability of the proposed controller. In the simulations, multiple aggressive flight trajectories and severe external disturbances are designed. The results show that the controller is robust, with superior accuracy in tracking aggressive trajectories.

As the size of tail-sitter electric vertical take-off and landing (eVTOL) aircraft increases, significant challenges have arisen due to a lower thrust-to-weight ratio, more nonlinear aerodynamics during transition, and slower control response. To support the design and implementation of the flight control system for the large-scale tail-sitter eVTOL Eagle of Taihu 100 (ET100), a one-third-scale, 13 kg subscale technology demonstrator, ET10, was developed. This paper presents the control framework tailored for ET series. In this framework, a refined state-error-based model predictive control (MPC) scheme is proposed. By reformulating the translational dynamics, the coupling between translation and rotation is explicitly captured. Aerodynamic feedforward and efficiency-aware control allocation are integrated to mitigate model uncertainties. A PX4 software-in-the-loop (SITL) platform was constructed by integrating data from computational fluid dynamics (CFD) simulations and experiments to ensure a high-fidelity aerodynamic modeling. Flight simulations were first conducted to evaluate the improved algorithm in terms of tracking performance across various tasks. Next, flight tests of the ET10 were conducted, demonstrating the reliability and robustness of the scheme across the full flight envelope.