Toward the Smooth Mesh Climbing of a Miniature Robot Using Bioinspired Soft and Expandable Claws

Unlike most micro robots that struggle to navigate rugged and uneven terrain, beetles exhibit remarkable agility, traversing complex substrates with ease. This remarkable locomotion is attributed to their unique adaptations, including stiffness-variable tarsi and expandable hooks at the tip of their tarsi, which prevent slipping and ensure a secure grip on the surface. In this study, we found that beetles actively bent and expanded their claws regularly to crawl freely on mesh surfaces. Inspired by the crawling mechanism of the beetles, a micro cable-and-pully-driven mechanism was designed and demonstrated to be most effective among four several different climbing strategies. After that, an 8-cm miniature climbing robot was assembled, equipping artificial claws to open and bend in the same cyclic manner as natural beetles. The robot can climb freely with a controllable gait on the mesh surface, steep incline of the angle of 60°, and even transition surface. To our best knowledge, this is the first micro-scale robot that can climb both the mesh surface and cliffy incline.