Model for wheel traction prediction on agricultural soils

The paper presents a model for the tractor drive wheel-terrain interaction, which enables the prediction of the net traction force and traction efficiency; the model assumes that traction is limited by the maximum soil shear stress, according to the Mohr-Coulomb criterion. In order to validate the model, traction experiments were made using the U 650 tractor -P2V plough; the variable working width of the plough has allowed the tractor to develop different traction forces. The experimental results were in accordance with the values predicted by our model.