Wheel-legged In-pipe Robot with a Bioinspired Hook and Dry Adhesive Attachment Device

In-pipe robots have been widely used in pipes–with smooth inner walls. However, current in-pipe robots face challenges in terms of moving past obstacles and climbing in marine-vessel pipeline systems, which are affected by marine biofouling and electrochemical corrosion. This paper takes inspiration from the dual-hook structure of Trypoxylus dichotomus’s feet and gecko‑like dry adhesives, proposing an in-pipe robot that is capable of climbing on rough and smooth pipe inwalls. The combination of the bioinspired hook and dry adhesives allows the robot to stably attach to rough or smooth pipe inwalls, while the wheel-leg hybrid mechanism provides better conditions for obstacle traversal. The paper explores the attachment and obstacle-surmounting mechanisms of the robot. Moreover, motion strategies for the robot are devised based on different pipe structural features. The experiments showed that this robot can adapt to both smooth and rough pipe environments simultaneously, and its motion performance is superior to conventional driving mechanisms. The robot’s active turning actuators also enable it to navigate through horizontally or vertically oriented 90° bends.