Analysis of Bearing Characteristics of Legged Robot's Flexible Sole in Soft Soil

Aiming at the sinking problem of the robot during walking in soft soil, an elastomer is used to robot foot, and the load-bearing characteristics are analyzed by simulation. The correction models of Drucker-Prager cap and Mooney-Rivlin are used as the constitutive models of soft soil and the elastomer respectively, and the ALE method is taken to carry out the numeric simulation of the sinking process of the flexible robot foot in soft soil. The bearing mechanism of the robot sole with a solid rubber body and pressure airbag in soft soil is studied. The results show that the load-bearing capacity of the robot foot with pressure airbag is improved under heavy loads. This is because the bottom of the pressure airbag gradually becomes a stable bow shape during the sinking process, which increases the load-bearing areas, and produces a certain effect of soil consolidation. The influence of airbag internal pressure on the bearing capacity of the robot foot is analyzed, and it is found that the larger the airbag internal pressure is, the greater the bearing capacity of the robot foot is. However, with the increase of the sinkage, the influence of the airbag internal pressure gradually decreases. The results show that the large deformation characteristics of elastomer have a positive influence on the bearing capacity of robot feet.