Lateral attitude control of solar-powered UAV with high aspect ratio

大展弦比太阳能无人机横航向姿态控制研究

¹ School of Aeronautics, Northwestern Polytechnical University, Xi'an 710072, China
² The First Aircraft Institute, Xi'an 710089, China

Received: 26 February 2022

Abstract

A solar-powered UAV usually has a high-aspect-ratio and flexible structural design. Its aerodynamic and mass characteristics are different from those of a conventional aircraft. This paper compares the differences in lateral aerodynamic data with those of Class I and Class III aircrafts. Based on the rigid-body dynamics theory, the effects of flexible wing deformation on the stability of the UAV are analyzed. Then, by combining the structural deformation, inertia variation and aerodynamic derivative, the solar-powered UAV's lateral stability is analyzed based on the root locus method. The variation of eigenvalues with wing deformation is also investigated. The rolling moment equation is combined with the kinematic equation to reveal the roll attitude limitation envelope constrained by the kinematic coupling and aileron effects. Taking into account the aerodynamic characteristics of the solar-powered UAV, its wing deformation and roll attitude limitation problem, this paper proposes an adaptive back-stepping control method with strong robustness to achieve the accurate control of the roll attitude of the solar-powered UAV.

摘要

太阳能无人机多采用大展弦比和轻质结构设计, 其气动特性和质量特性与传统飞机显著不同。详细对比分析了太阳能无人机横航向气动数据与I类、III类飞机的差异。依据刚体动力学理论, 揭示了机翼静态变形对飞机稳定性的影响。进一步利用根轨迹法深入分析了太阳能无人机横航向稳定性, 研究了特征根随机翼变形的变化规律。将飞机稳定转弯时的力矩方程与动力学方程结合, 揭示了受运动耦合和副翼舵效约束的滚转姿态安全边界。针对太阳能无人机的气动特点、飞机特性受机翼上反变形影响较大以及滚转姿态限制问题, 提出了采用具有强鲁棒性的自适应反步法, 实现太阳能无人机滚转姿态的精确控制。