[论文解读] An Experimental Study of Wind Resistance and Power Consumption in MAVs with a Low-Speed Multi-Fan Wind System

Diana A. Olejnik, Sunyi Wang+5 more|arXiv (Cornell University)|Feb 14, 2022

Biomimetic flight and propulsion mechanisms被引用 4

一句话总结

本文提出一种开源、低成本、多风扇风洞系统，用于实验性微型飞行器（MAV）测试，可实现受控的稳定风和阵风条件。对扑翼飞行器和四旋翼机的实验表明，扑翼飞行器在高风速下需要更大的俯仰角并能从升力中受益，而CrazyFlie四旋翼机则表现出更稳定的功耗和更快的阵风响应，凸显了该系统在提升MAV抗风能力方面的价值。

ABSTRACT

This paper discusses a low-cost, open-source and open-hardware design and performance evaluation of a low-speed, multi-fan wind system dedicated to micro air vehicle (MAV) testing. In addition, a set of experiments with a flapping wing MAV and rotorcraft is presented, demonstrating the capabilities of the system and the properties of these different types of drones in response to various types of wind. We performed two sets of experiments where a MAV is flying into the wake of the fan system, gathering data about states, battery voltage and current. Firstly, we focus on steady wind conditions with wind speeds ranging from 0.5 m/s to 3.4 m/s. During the second set of experiments, we introduce wind gusts, by periodically modulating the wind speed from 1.3 m/s to 3.4 m/s with wind gust oscillations of 0.5 Hz, 0.25 Hz and 0.125 Hz. The "Flapper" flapping wing MAV requires much larger pitch angles to counter wind than the "CrazyFlie" quadrotor. This is due to the Flapper's larger wing surface. In forward flight, its wings do provide extra lift, considerably reducing the power consumption. In contrast, the CrazyFlie's power consumption stays more constant for different wind speeds. The experiments with the varying wind show a quicker gust response by the CrazyFlie compared with the Flapper drone, but both their responses could be further improved. We expect that the proposed wind gust system will provide a useful tool to the community to achieve such improvements.

研究动机与目标

• 开发一种低成本、开源且开放硬件的多风扇风洞系统，用于室内MAV测试。
• 在受控的稳定风和阵风条件下，评估扑翼飞行器和旋翼类MAV的抗风能力和功耗表现。
• 提供一个可扩展、易获取的实验平台，以提升MAV在真实风环境下的飞行控制能力。
• 比较生物仿生扑翼飞行器与传统四旋翼机在风扰动下的气动性能与能量效率。

提出的方法

• 系统由135个轴流风扇组成，划分为15个模块，每个模块配备基于AVR的微控制器，用于PWM控制和转速反馈。
• 风速通过Raspberry Pi独立控制各风扇实现调节，可精确调制以生成稳定风和周期性阵风。
• 系统可生成0.5 m/s至3.4 m/s的风速，并通过循环调节风扇转速，在0.125 Hz、0.25 Hz和0.5 Hz频率下引入阵风。
• 从两架MAV中采集飞行数据，包括电池电压、电流和状态估计值：扑翼飞行器‘Flapper’和四旋翼机‘CrazyFlie’。
• 实验分为两个阶段：在不同风速下的稳定风测试，以及具有受控振荡频率的周期性阵风测试。
• 数据分析包括对俯仰角、位置和功耗的时间序列追踪，采用三次样条平滑法拟合平均功耗趋势。

实验结果

研究问题

• RQ1 在稳定来流风条件下，扑翼飞行器与四旋翼飞行器在俯仰角响应上有哪些差异？
• RQ2 扑翼飞行器与旋翼类飞行器的功耗与风速之间存在何种关系？
• RQ3 MAV对不同频率（0.125 Hz、0.25 Hz、0.5 Hz）的周期性阵风如何响应？
• RQ4 所提出的多风扇风洞系统能否有效模拟真实风况以用于MAV测试？
• RQ5 哪些设计局限性会影响扑翼飞行器在高风速场景下的稳定性和控制性能？

主要发现

• 由于扑翼飞行器‘Flapper’的机翼表面积更大，其需要显著高于‘CrazyFlie’的俯仰角以抵抗风力影响。
• 当风速超过2.7 m/s时，‘Flapper’的功耗降至最低值12.7 W，表明其机翼能有效产生有益升力。
• ‘CrazyFlie’四旋翼机在不同风速下功耗保持约8.8 W的稳定水平，表现出对风速变化的较低敏感性。
• ‘CrazyFlie’对风阵风的响应速度明显快于‘Flapper’，后者甚至在3.4 m/s的稳定风中也难以维持位置。
• ‘Flapper’的姿态控制系统在俯仰角超过40°时性能受限，需依赖姿态相关的推力映射才能实现稳定水平飞行。
• 两类MAV在阵风响应方面均有改进空间，凸显了在所提出的开源硬件风洞系统上验证先进控制算法的必要性。