John A Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.
Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA.
Nature. 2019 Jun;570(7762):491-495. doi: 10.1038/s41586-019-1322-0. Epub 2019 Jun 26.
Heavier-than-air flight at any scale is energetically expensive. This is greatly exacerbated at small scales and has so far presented an insurmountable obstacle for untethered flight in insect-sized (mass less than 500 milligrams and wingspan less than 5 centimetres) robots. These vehicles thus need to fly tethered to an offboard power supply and signal generator owing to the challenges associated with integrating onboard electronics within a limited payload capacity. Here we address these challenges to demonstrate sustained untethered flight of an insect-sized flapping-wing microscale aerial vehicle. The 90-milligram vehicle uses four wings driven by two alumina-reinforced piezoelectric actuators to increase aerodynamic efficiency (by up to 29 per cent relative to similar two-wing vehicles) and achieve a peak lift-to-weight ratio of 4.1 to 1, demonstrating greater thrust per muscle mass than typical biological counterparts. The integrated system of the vehicle together with the electronics required for untethered flight (a photovoltaic array and a signal generator) weighs 259 milligrams, with an additional payload capacity allowing for additional onboard devices. Consuming only 110-120 milliwatts of power, the system matches the thrust efficiency of similarly sized insects such as bees. This insect-scale aerial vehicle is the lightest thus far to achieve sustained untethered flight (as opposed to impulsive jumping or liftoff).
任何规模的重于空气的飞行在能量上都是昂贵的。在小尺度上，这一点被极大地放大了，迄今为止，对于无绳飞行在昆虫大小（质量小于 500 毫克，翼展小于 5 厘米）的机器人来说，这仍然是一个无法克服的障碍。由于在有限的有效载荷能力内集成机载电子设备所带来的挑战，这些飞行器因此需要与外部电源和信号发生器连接才能飞行。在这里，我们解决了这些挑战，展示了一种昆虫大小的扑翼微型空中飞行器的持续无绳飞行。这款 90 毫克重的飞行器使用四个由两个氧化铝增强型压电致动器驱动的机翼，以提高空气动力学效率（相对于类似的双翼飞行器提高了 29%），并实现了 4.1 比 1 的峰值升力重量比，展示出比典型生物对应物更大的每肌肉质量推力。该飞行器的集成系统以及无绳飞行所需的电子设备（光伏阵列和信号发生器）重 259 毫克，还有额外的有效载荷能力，可以容纳额外的机载设备。该系统仅消耗 110-120 毫瓦的功率，其推力效率与类似大小的昆虫（如蜜蜂）相当。与类似大小的昆虫相比，这种昆虫大小的空中飞行器是迄今为止实现持续无绳飞行（而不是脉冲式跳跃或起飞）的最轻飞行器。
