Passive Expandable Foot Mechanism for Multi-Legged Locomotion Over Muddy Terrain

This paper proposes a new foot design for a multi-legged robot that enhances the capability of walking on muddy soil. The foot functions passively according to the movement of a leg, which allows it to attach to any existing multi-legged robot without modifying a built-in robot controller. The area-extension plates' passive opening and closing mechanism with round edges allow the foot to sustain the robot's weight and reduce the peeling-off force from the mud surface. We have conducted locomotion experiments on muddy soil by using a six-legged robot and compared the effectiveness of the proposed self-opening foot with the conventional foot and the foot that is always open. The results showed that the proposed foot achieved the longest distance locomotion, especially on soft muddy soil similar to a rice paddy's environment.