Analysis of Overturning Stability of Small off-Road Vehicle

Purpose: Vehicles are in danger of overturning during field operations because of variations in the terrain slope. Ensuring the stability of such agricultural vehicles can contribute to the safety, reducing the occurrence of accidents in farm operations. Active research on the overturning of tractors is being conducted; however, research on the overturning of small off-road vehicles, and the manufacturing and usage guidelines for such vehicles is limited. The purpose of this study is to conduct a theoretical analysis of the overturning stability of small off-road vehicles. Methods: The characteristics of the backward roll-over and lateral overturning of a small off-road vehicle were summarized using an equation and performed assuming three situations. The backward roll-over stability analysis yielded the critical angular velocity of the vehicle that caused backward roll-over, depending on the angle at which the front wheel is lifted. The lateral overturning stability analysis yielded the critical traveling speed that induced lateral overturn as a result of a change in the steering angle of the vehicle. Results: The analysis showed that when the center of gravity of the vehicle moved forward, it also moved vertically downward and that when the width of the vehicle increased, the stability with respect to backward roll-over and lateral overturning increased. Conclusions: The results demonstrate how geometric features of small off-road vehicles can be designed to achieve stability movement around narrow round ridges or open fields of orchards. In addition, this research on vehicle driving stability lays the groundwork for related research on other types of field agricultural machines.