Discoveries in geckos locomotion have advanced the bio-inspired robotics. However, the gecko-inspired robots still lag behind animals in attachments and maneuvers due to our failure to understand and implement gecko bionics thoroughly. Here, we studied the toe deployments that facilitate the upside-down motion of geckos by focusing on the directions and contact area of toes to offer inspirations for the design and control of feet of legged robots that must operate on inverted surfaces. Instead of clustering toes, geckos align toes in varying directions. They distribute adhesion to toes by controlling the magnitude of contact area, with one square millimeter setae generating ∼153.8 mN shear force and ∼39.5 mN attractive force on ceilings. Front feet deploy toes in a ∼190° span that centers on ∼16° from the motion direction. Toes distribute uniformly and contribute similarly. Whereas, hind feet deploy toes in a ∼220° span centering around ∼90° relative to the fore-aft direction. The last two toes point toward the rear and contribute most in hind feet while the first two toes adhere barely. Such deployments involving distributed control among toes not only provide insight into biological adhesion but will also deliver useful information to the next generation of climbing robotics.

中文翻译：

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壁虎在颠倒的跑步过程中向脚趾分配粘附力为机器人提供了生物灵感

壁虎运动的发现推动了受生物启发的机器人技术的发展。但是，由于我们无法完全理解和实施壁虎仿生，因此受到壁虎启发的机器人在附着和机动方面仍然落后于动物。在这里，我们通过关注脚趾的方向和接触区域研究了有助于壁虎上下颠倒运动的脚趾展开，从而为必须在倒置表面上操作的有腿机器人的脚的设计和控制提供了灵感。壁虎不是将脚趾聚类，而是将脚趾在不同的方向上对齐。他们通过控制接触面积的大小来分配对脚趾的附着力，一平方毫米的刚毛在天花板上产生约153.8 mN的剪切力和约39.5 mN的吸引力。前脚以约190°的跨度展开脚趾，该跨度从运动方向以约16°为中心。脚趾均匀分布，起着相似的作用。而后脚相对于前后方向以大约90°为中心在大约220°的范围内展开脚趾。后两个脚趾指向后方，后脚贡献最大，而前两个脚趾勉强附着。这种涉及脚趾间分布式控制的部署不仅可以洞悉生物附着力，还可以为下一代的攀爬机器人提供有用的信息。