Retractable cleat mechanism of legged robots' foot on various terrain

Many locomotive robots aim to work reliably and quickly on various terrain. However, It is difficult to control the robot because the terrain is sometimes bumpy, slippery, and muddy. This paper presents a solution for slippery terrain. Slip is an event caused by a lack of friction force. The key research question of this study was whether a relationship between friction force and cleat of a cat's. If legged robots have foot structure for various terrain, such as claws, then the traction force would be increased and slip would not happen. Moreover, the foot structure was designed as a retractable claw to that can be applied to various ground conditions. The change of the friction force with the ground was demonstrated by experiments. The experiments compared with the coefficient of friction in case with or without the cleat on the three terrain conditions: asphalt, ice and soil. As a result, in case with the cleat, the friction force was increased than without.