Design of a Spiny Foot with Fluid-filled Sacs for Climbing Robots

Abstract

This paper proposes a bioinspired spiny foot for wall-climbing robots. Inspired by the fluid-filled sac under the lamella in gecko's foot, a fluid-filled sac with soft membrane is designed to ensure that the contact force between spiny foot and the climbing surface are evenly distributed among all spines. Each spine has two degrees of freedom, and the tangential motion and normal motion of all spines are actuated by two fluid-filled sacs respectively. When the spiny foot tries to adhere on the rough surface, spines move along the surface to find a proper asperity and engage on it. Although the moving displacements of spines are different, the tangential forces as well as the normal forces acted on spines are almost the same due to the constant hydraulic pressure in sacs behind them. With this load-sharing capacity, the spiny foot's adhesion property is significantly improved, and it could be used in improving the climbing stability and load-capacity of climbing robots.