Bipedal-Walking-Dynamics Model on Granular Terrains

TL;DR

This paper introduces a new dynamics model for bipedal walking on granular terrains like sand, incorporating foot sinkage and slip to improve prediction and control of robot locomotion.

Contribution

A novel granular dynamics model with additional degrees of freedom for sinkage and slip, validated through experiments on a sand-walking robot.

Findings

Model accurately predicts ground reaction forces on sand.

Incorporating sinkage and slip improves gait stability predictions.

Model enables better control strategies for walking on granular media.

Abstract

Bipeds have demonstrated high agility and mobility in unstructured environments such as sand. The yielding of such granular media brings significant sinkage and slip of the bipedal feet, leading to uncertainty and instability of walking locomotion. We present a new dynamics-modeling approach to capture and predict bipedal-walking locomotion on granular media. A dynamic foot-terrain interaction model is integrated to compute the ground reaction force (GRF). The proposed granular dynamic model has three additional degree-of-freedom (DoF) to estimate foot sinkage and slip that are critical to capturing robot-walking kinematics and kinetics such as cost of transport (CoT). Using the new model, we analyze bipedal kinetics, CoT, and foot-terrain rolling and intrusion affects. Experiments are conducted using a biped robotic walker on sand to validate the proposed dynamic model with robot-gait profiles, media-intrusion prediction, and GRF estimations. This new dynamics model can further serve as an enabling tool for locomotion control and optimization of bipedal robots to efficiently walk on granular terrains.