Agility, as a property to provide a fast and exact response to dynamical changes in severe environments, is becoming a required feature to many applications of unmanned ground vehicles (UGV). This paper develops analytical fundamentals to model the interaction between stochastic correlated terrain properties with the entire small UGV with four independently driven pneumatic wheels.

Starting with stochastic modeling of major terramechanics-based characteristics by spatial distribution of geotechnical properties in soil, the paper derives stochastic longitudinal and lateral forces at all four wheels for the UGV while moving in a curvilinear motion. Modeling the spatial occurrence of soil properties within a probabilistic framework is necessary for accurate numerical modeling of terrain with heterogeneous properties. The kinematic, together with the force factors, determine the power that is supplied to the wheel and its part that is lost in the tire-soil interaction. It should be emphasized that these factors are highly affected by the properties of the surface of motion.

Moreover, the paper addresses the stochastic energy efficiency and stochastic slip power losses in the tire-soil interaction of the four tires of the UGV.