Application of a dynamic pressure-sinkage relationship for lightweight mobile robots

This paper investigates a dynamic pressure-sinkage relationship which can be used in a wheel-soil model to better capture periodic variations observed in sinkage, drawbar pull and normal force as a rigid wheel interacts with loose sandy soil. The dynamic wheel-soil model can be used for wheels with or without grousers. Several case studies are presented to demonstrate the usefulness and applicability of this dynamic pressure-sinkage relationship. Hill climbing experiments were carried out using a smooth-wheel micro rover with a fixed suspension to confirm operational regions of the dynamic pressure-sinkage relationship. Single wheel testbed experiments were carried out to determine how well the model can predict changes in the number and length of the grousers on the wheel. It was concluded that dynamic pressure-sinkage relationship can predict the observed oscillations in the sinkage, drawbar pull and normal force with a single tuning case as the slip ratio and the configuration of the wheel changes.