Study on the performance of robot feet on sand with varying saturation levels

Details

Supervisors

Legat, Vincent ; Lambrechts, Jonathan

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil mécanicien, à finalité spécialisée

Abstract

enLocomotion in granular media, such as dry or wet sand, presents significant challenges for legged robots due to the variability in the soil’s response to intrusion at different saturation levels. This study aims to evaluate the performance of various foot geometries, including concave shapes, in dry and low-saturation sand, with the goal of improving robotic mobility in such environments. Experiments were conducted using controlled intrusion tests in sand at various saturation levels, supported by 2D Discrete Element Method (DEM) simulations and analytical modeling using Resistive Force Theory (RFT). The results show that convex foot geometry generates the lowest vertical resistive force, while the flat foot exhibits the highest. Concave foot geometry demonstrates improved resistive force performance at greater intrusion depths, particularly under low-saturation conditions. Implementation of cohesion in the DEM solver enables the observation of granular structures and underlying physical mechanisms that link intruder shape to resistive force in both dry and wet granular media. These findings offer design insights for engineers developing legged robots for locomotion in challenging granular terrains.