展开式变体垂直起降飞行器气动布局与控制策略设计及飞行验证

Aerodynamic layout and control strategy design and flight verification of a wing-foldable variant VTOL aircraft

垂直起降飞行器具有固定翼飞行器飞行航程远、飞行速度快的性能优势,又同旋翼飞行器一样机动灵活,具有垂直起降的功能,近年来成为飞行器研究领域的研究热点之一。尤其是尾座式垂直起降飞行器由于其结构简单、重量利用率高等优点,受到了较多关注。本文提出了一种机翼可展开的尾座式变体垂直起降飞行器总体布局方案,为该布局设计了一种具有自锁功能的机翼变体驱动机构。利用风洞测力实验对飞行器固定翼巡航模态、四旋翼悬停模态及变体过渡过程的气动力进行研究,给出了飞行器在固定翼巡航模态下的配平能力与飞行性能,及前倾加速及变体过渡过程中的气动特性。并提出了一种升降副翼-旋翼协调航向增强控制策略,有效提升飞行器悬停模态的航向控制力矩。通过对飞行器变体转换过程的受力情况研究,为该构型飞行器设计了一种基于空速与俯仰姿态角的变体过渡控制策略。对该构型飞行器进行了飞行试验验证,结果表明飞行器在四旋翼悬停和固定翼巡航模态下表现出良好的操纵性和抗风能力,成功实现了平稳的无高度损失模态转换,验证了控制策略的有效性。

Vertical Takeoff and Landing(VTOL) aircraft combine the performance advantages of fixed-wing aircraft,such as long flight range and high speed,with the maneuverability and vertical takeoff and landing capabilities of rotorcraft.In recent years,VTOL aircraft have become a hot topic in the field of aircraft research.Tail-sitter VTOL aircraft,in particular,have garnered significant attention due to their simple structure and high weight efficiency.This article proposes a general layout scheme for a variable-wing tail-sitter VTOL aircraft,and designs a wing variant actuation mechanism with the self-locking function.Wind tunnel force measurements are conducted to study the aerodynamics of the aircraft in the fixed-wing cruise mode and quadcopter hover mode,and during the transition between these modes.The results offer valuable insights into the aircraft's trimming capabilities and its flight performance in the fixedwing cruise mode,as well as the aerodynamic characteristics during the forward transition phase.An elevon-rotor coordinated yaw enhancement control strategy is introduced to improve the yaw control effectiveness during the hover mode.By studying the aerodynamic forces acting on the aircraft during the transition process,a transition control strategy based on the airspeed and pitch attitude angle is developed.Flight tests are conducted to validate the aircraft's performance,demonstrating good maneuverability and wind resistance of the aircraft in the quadcopter hover and fixed-wing cruise modes.The successful and smooth mode transitions without altitude loss validate the effectiveness of the control strategies.