Trajectory tracking control of tilt-propulsion UAV vertical take-off and landing mode based on NLESO

Aiming at the vertical take-off and landing mode of tilt-propulsion UAV with uncertainties such as external environment disturbance and internal parameter perturbation, this paper studies the trajectory tracking control, and proposes an internal and external double loop sliding mode control scheme based on nonlinear extended state observer (NLESO). Firstly, according to the characteristics of tilt-propulsion UAV, the dynamic model of propulsion system, aerodynamic model of fuselage/wing and yaw rudder, and dynamic equation are established in turn to complete the dynamic modeling work. Then, the internal and external uncertainties are regarded as lumped disturbances, and NLESO is designed to estimate them and compensate the control system. Afterwards, based on NLESO and sliding mode control method, the position and attitude double loop controller of VTOL mode is designed. Finally, the Lyapunov function is designed to analyze the stability of NLESO and the whole control system. Simulation results show that the proposed method significantly improves the trajectory tracking response speed and the ability to suppress uncertainties of vertical take-off and landing mode of tilt dynamic UAV.