Numerical analysis of wheel locomotion on soft soil using the extended terramechanics model based on cellular automata

Abstract

The evaluation of the traveling performance of moon/planetary exploration rovers is the primary aspect of scientific missions and human exploration in space. However, conventional models lack the detailed description of mechanical interaction between the wheels and soft soil. Therefore, in this study, the effectiveness of an extended terramechanics (xTerramechanics) model was investigated by considering the soil deformation actions based on cellular automata for the evaluation of rover traveling performance. First, the results of single-wheel traveling analysis were compared with the experimental results under the forced-slip condition, and it was shown that drawbar-pull and sinkage were represented with good accuracy (mean absolute errors less than 5.5 N and 3.2 mm). Next, we applied the xTerramechanics model under the self-propelled traveling condition at a constant towing load and slope climbing. The model successfully reproduced the well-known “difference in traveling performance depending on traveling conditions.” Furthermore, we used the model for the multibody dynamics analysis of a simple rover, and its applicability to the examination of the overall vehicle performance and multipath effects was demonstrated.