Study on longitudinal stability of ducted vertical take-off and landing fixed-wing UAV

涵道式垂直起降固定翼无人机纵向稳定性研究

School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072, China

Received: 17 November 2020

Abstract

The longitudinal flight stability of the ducted vertical take-off and landing fixed-wing UAV during the flight state of hovering and transition is studied. Firstly, based on the Blade-Element Momentum Theory (BEMT) and experimental data, a coaxial dual-rotor ducted aerodynamic model and a thrust ducted aerodynamic model based on characteristic cross-section calculations are established. The model parameters are identified according to the experimental data. Secondly, a UAV flight dynamics model with thrust duct deflection is established according to the six-degree-of-freedom equations. Finally, the case UAV was used to solve the longitudinal balance and stability analysis of hovering and transition state with the established model method, and compared with the hovering experimental results. The results show that the UAV flight dynamics model combined with the ducted dynamic model established in the article can accurately describe the longitudinal flight stability characteristics of this type of aircraft.

摘要

针对涵道式垂直起降固定翼无人机飞行过程中的悬停和过渡2个飞行状态，进行了纵向飞行稳定性研究。根据叶素动量理论结合实验数据，建立了基于特征截面计算的共轴双旋翼涵道气动力模型和推力涵道气动力模型，模型参数依照实验数据进行辨识；根据六自由度方程建立带推力涵道偏转的无人机飞行动力学模型；以建立的模型方法对案例无人机进行了悬停和过渡状态的纵向平衡求解和稳定性分析，并与悬停实验结果进行了比较。结果显示所建结合涵道动力模型的无人机飞行动力学模型能够准确地描述此类飞行器的纵向飞行稳定性。