Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore.
Bioinspir Biomim. 2021 Nov 1;16(6). doi: 10.1088/1748-3190/ac253a.
The monocopter is a type of micro aerial vehicle largely inspired from the flight of botanical samaras (). A large section of its fuselage forms the single wing where all its useful aerodynamic forces are generated, making it achieve a highly efficient mode of flight. However, compared to a multi-rotor of similar weight, monocopters can be large and cumbersome for transport, mainly due to their large and rigid wing structure. In this work, a monocopter with a foldable, semi-rigid wing is proposed and its resulting flight performance is studied. The wing is non-rigid when not in flight and relies on centrifugal forces to become straightened during flight. The wing construction uses a special technique for its lightweight and semi-rigid design, and together with a purpose-designed autopilot board, the entire craft can be folded into a compact pocketable form factor, decreasing its footprint by 69%. Furthermore, the proposed craft accomplishes a controllable flight in 5 degrees of freedom by using only one thrust unit. It achieves altitude control by regulating the force generated from the thrust unit throughout multiple rotations. Lateral control is achieved by pulsing the thrust unit at specific instances during each cycle of rotation. A closed-loop feedback control is achieved using a motion-captured camera system, where a hybrid proportional stabilizer controller and proportional-integral position controller are applied. Waypoint tracking, trajectory tracking and flight time tests were performed and analyzed. Overall, the vehicle weighs 69 g, achieves a maximum lateral speed of about 2.37 m s, an average power draw of 9.78 W and a flight time of 16 min with its semi-rigid wing.
单旋翼直升机是一种微型飞行器，主要灵感来自植物翅果的飞行（）。其机身的大部分形成了单翼，所有有用的空气动力都产生于此，使其实现了高效的飞行模式。然而，与重量相似的多旋翼飞行器相比，单旋翼直升机在运输时可能会很大且笨重，主要是因为它们的机翼结构又大又硬。在这项工作中，提出了一种具有折叠式半刚性机翼的单旋翼直升机，并研究了其飞行性能。当不在飞行状态时，机翼是非刚性的，依靠离心力在飞行过程中变直。机翼结构采用特殊技术实现轻质和半刚性设计，再加上专门设计的自动驾驶仪板，整个飞行器可以折叠成紧凑的口袋式外形，将占地面积减少 69%。此外，该飞行器通过使用单个推力单元即可在 5 个自由度内实现可控飞行。它通过调节整个多个旋转周期中推力单元产生的力来实现高度控制。通过在每次旋转周期的特定时刻脉冲推力单元来实现横向控制。使用运动捕捉摄像头系统实现闭环反馈控制，其中应用了混合比例稳定器控制器和比例积分位置控制器。进行了航点跟踪、轨迹跟踪和飞行时间测试和分析。总体而言，该飞行器重 69 克，最大横向速度约为 2.37 米/秒，平均功耗为 9.78 瓦，半刚性机翼的飞行时间为 16 分钟。
