Prediction of tractor sideslipping behavior using a quasi-static model

Abstract

Tractor stability predominantly determines operator's safety. For a tractor parking on lateral slopes, overturning accidents have been frequently discussed using mathematical models. While the existing static models remarkably contribute tractor overturning mechanisms, few of them have considered the stability from the perspective of tractor sideslip. In our study, a relatively precise quasi-static model presented recently was adopted as the base model. We expanded it by introducing potential tractor sideslips. While the original model pointed out the lateral slope angle as the main factor influencing tractor overturns, we investigated tractor slipping stability under the influences of the slope angle and the coefficient of friction. The dimensional parameters of the example tractor for simulation were set the same as those in the original work. It was found that the allowable friction forces of both the front and rear tires primarily depended on the coefficient of friction rather than the slope angle. By comparing the surfaces of the allowable friction forces and the corresponding friction forces, tractor slipping thresholds for the front and rear tires were identified. Caution areas implying certain ground conditions that will definitely cause tractor sideslip were marked accordingly. The results shown in this study provide a relatively comprehensive way to understand tractor static stability when both tractor sideslip and overturn are concerned.