Enhancing Tractor Safety over rough Terrains: A Numerical Study of Steering Instability

Tractor overturn accidents pose a significant safety concern in agriculture, particularly in Korea where small tractors navigate challenging terrains like slippery fields and steep slopes. The risk stems from steering instability induced by bouncing and sliding, impacting both tractor safety and trajectory tracking precision in autonomous driving. The agricultural industry is shifting towards alternative energy sources such as electric and hydrogen tractors, necessitating a reevaluation of safety concerns due to changes in the tractor's center of gravity. This study focuses on a numerical investigation of tractor steering instability, combining bouncing and sliding models based on Coulomb's friction theory. Numerical experiments are conducted, varying parameters like travel velocity, static friction coefficient, bump length, and turning radius. A turning test evaluates the fundamental steering performance. Simulation results demonstrate that bouncing and sliding reduce cornering force, deviating from the desired trajectory. Operating the tractor on steep slopes exacerbates steering instability, potentially leading to overturn accidents under unfavorable conditions. These findings provide crucial insights for improving tractor safety in challenging agricultural settings.