PREDICTION OF WHEEL TRACTION PERFORMANCE BY ANALYSIS OF TIRE-GROUND INTERACTION

摘要

The paper presents a traction model for the driving wheel of the U-650 romanian tractor. Tire deflection under load was taken into account by replacing the real wheel with an imaginary one, with a larger radius. The model was developed in order to calculate the net traction force and traction efficiency of the wheel, as defined by the ASAE S296 standard; the net traction coefficient was also evaluated. It was assumed that the maximum traction force of the tire was limited only by the soil maximum shear strength, as defined by the Mohr-Coulomb criterion. A variable shear area, depending upon wheel slip, was taken into account. The theoretical results were compared with the experimental data; the field experiments were developed using the U-650 tractor, equipped with the P2V plow. Variation of plow width and depth allowed different traction forces and drive wheel slip to be obtained. Drive wheel slip and net traction force were measured directly, while the gross traction force and traction efficiency were determined with a formula derived from ASAE S296 standard.