In this paper we particularly look at the wheel-terrain contact pair; the basic building block for vehicle terrain models. We will analyze the possible ways to model and simulate this interaction pair. The main goal of terramechanics modelling is to determine the effect of the distributed ground reaction force system on the wheel, and through that, the effect on the vehicle. From the modelling point of view we can then consider the dynamic behaviour of the wheel as the main modelling objective, and analyze the motion of the wheel relative to an absolute frame of reference. This motion is affected by the ground force system. Terramechanics approaches generally implicitly assume that the wheel can be modelled as a rigid body from the point of view of its global motion behaviour. Only with such assumption can a distributed force system be replaced by its resultants as it is typically done in wheel-terrain models. These resultants represent the force and moment components related to traction, compaction, side force, and motion resistance, for example. We will describe and analyze a range of possibilities of how these resultants can be determined and interpreted to represent the distributed force system and include the information about the material constitution of the ground into the model. We will present detailed implementation studies and simulation results by using semi-empirical and experimental terramechanics models, and evaluate the different approaches.
展开▼
