Development and experimental validation of an improved pressure-sinkage model for small-wheeled vehicles on dilative, deformable terrain

This paper presents a novel pressure-sinkage model for small-wheeled vehicles operating on dilative, deformable soils. Dilative soils, such as sand and Martian regolith, undergo negligible compaction during deformation. The proposed model takes both wheel diameter and width into account and is established using results from over 120 pressure-sinkage tests on two soils and 35 wheel geometries. The model builds on the authors’ previously established diameter dependent pressure-sinkage relationship, which has been shown to be more accurate for small wheels than classical models. X-ray images of the sub-surface strain field during soil indentation are used to visually validate the model. Using this model, an improved terramechanics framework is developed, which is subsequently implemented in an A∗ path planning algorithm. The algorithm determines the optimal route for an unmanned ground vehicle based on distance, energy consumption, and mobility. Field tests performed using a four-wheeled experimental UGV on moist, sandy terrain validate the modified terramechanics framework and its usefulness in field operations.