Real-Time Modeling of Environmental Forces During Pushing in Granular Media Using S-RFT

Abstract

Modeling environmental forces remains a critical challenge in the design and control of robots operating on granular terrain. In pushing locomotion, propulsion is generated by displacing a large number of particles; however, the resulting terrain deformation complicates accurate real-time force prediction. Most existing resistive force models do not explicitly account for these deformation effects. To address this limitation, we develop a force model that incorporates motion-induced terrain deformation for pushing motions in granular media. A wheel lug is adopted as a representative element. We first investigate translational motion using the discrete element method (DEM) to characterize terrain deformation under different velocity directions. The analysis identifies dominant deformation patterns, which are embedded in the force model. Building on this analysis, we examine the rotational motion of a single lug through experiments, DEM simulations, and model predictions. The results demonstrate that the proposed model accurately captures force responses across varying velocity directions, exhibiting closer agreement with DEM and experiments than conventional approaches. This work advances real-time force modeling for robot-granular terrain interactions and highlights the potential of deformation-integrated models in deformable environments.