Abstract: A variety of soft wall-climbing robots have been developed that can move in certain patterns. Most of these soft robots can only move on conventional surfaces and lack adaptability to complex surfaces. Improving the adaptability of soft robots on complex surfaces is still a challenging problem. To this end, we study the layered structure of the starfish tube foot and the valve flap structure in the water vascular system, and use an ultrasonic stress detector to study the stiffness distribution of the arm structure. Inspired by the motion of the starfish, we present a bionic soft wall-climbing robot, which is driven by two groups of pneumatic feet and achieves body bending through active adaptation layers. We design the structure of the foot to flex to provide driving force, and there are suction cups at the end of the foot to provide suction. The soft foot has a simple structure design, adapts to a variety of surfaces, and does not damage the surface of the substrate. Variable stiffness layers achieve stiffness changes by the principle of line blocking. The Central Pattern Generator theory is introduced to coordinately control the multiple feet of the robot. After experiments, we verify the adaptability of the soft robot to curved surfaces. The research may provide a reference for the design and development of crawling soft robots on complex surfaces.

Key words: Starfsh , · Tube foot , · Biomimetic robot , · Soft robot , · Climbing robot