Design of Anti-Skid Foot With Passive Slip Detection Mechanism for Conditional Utilization of Heterogeneous Foot Pads

This letter introduces a novel anti-skid foot design consisting of two different types of foot pads, a cylindrical foot covered with rubber and a complementary foot with an array of spine mechanisms. The primary foot is designed to provide contact during movements that do not require excessive friction forces. On the other hand, the complementary foot is specialized to provide larger traction for dynamic motions. A passive slip detection and lock and release mechanisms are also designed to enable conditional switching to the complementary foot pad if slip occurs while the primary foot is in use. Experimental results demonstrated that the anti-skid foot can sustain 1.9 times of tangential load on a concrete block, compared with the maximum tangential load that a rubber foot pad can sustain on the same surface. Using this enhanced tangential load capability, a two-legged planar robot equipped with the novel foot was able to jump, land, and attach to the surface of a concrete block with a slope of 50°.