Modeling the stability of wheeled agricultural tractors

O conhecimento do limite de estabilidade de tratores é fundamental à segurança das operações agrícolas. O objetivo deste trabalho foi desenvolver um modelo matemático para previsão da perda da estabilidade de tratores agrícolas. No modelo foram utilizadas as características geométricas e ponderais do trator e de sua condição numa pista de ensaio. Análises de balanço de forças e de momentos foram realizadas para determinar as equações que regem o comportamento estático e dinâmico do trator em superfície inclinada. Com base nos resultados da comparação entre os valores dos ângulos-limite de tombamento simulados e experimentais, conclui-se que o modelo matemático desenvolvido é capaz de prever a perda da estabilidade de trator 4x2 satisfatoriamente.The knowledge of the stability limit of tractors is fundamental to the safety of the agricultural operations in order to avoid accidents. The objective of this research was to develop a mathematical model to predict the loss of tractor stability. The model was verified under dynamic conditions on a standardized track, with no implement attached to the tractor. In order to predict the loss of tractor stability, the mathematical model was implemented based on the tractor geometry and weight and on some information about the tractor placement on the track. Forces and momentum analyses were accomplished to determine the equations that describe the static and dynamic tractor behavior on sloping terrain. It was used a 4x2 tractor. Comparing the experimental to the model estimated tractor-overturning angle, it was concluded that the developed model is capable to predict the stability loss