Studies on the Running of Tractor on the Slope (1)

Abstract

In order to clarify the behavior of tractor on the slope, the running loci on the slope were studied For the tractor running on the slope, the difference of the driving force between wheels on both side of axle can be found depending on the running resistance of wheel on the basis of the weight difference of wheel axis between wheels on both side of axle, consequently it leads to the
speed difference of wheels on both side of axle. Therefore, the turning center is formed on the turning center is formed on the valley side due to the speed difference, and the tractor turns downward. Therefore, the running locus when the actual steering angle δ is zero, namely in case of no steering, it is expressed by the following equation.
x=-FD²/2μWhsinθ∫^t_t0√1-sin²θsin²tdt
t=π/2-φ
y=FD²/2μWhsinθ(√1-u₀²-√1-u²-ln1+√1-u₀²/u₀+ln1+√1-u²/u)
u=sinθcosφ
In order to make the tractor run on a contour line, it is necessary to give the actual steering angle δ in which the turning center is formed on the mountain side of the tractor so that the speed difference between wheels on both side of axle is eliminated. The running locus in case of such a steering is expressed by the following equation.
x=∫^φ_φ0FD²cosφdφ/2μWhsinφcosφ/√1-sin²θcos²φ-FD²/1cotδ
y=∫^φ_φ0FD²sinφdφ/2μWhsinφcosφ/√1-sin²θcos²φ-FD²/1cotδ
Model test and actual vehicle test were carried out. For the actual vehicle test, a 14 PS tractor was used, and the running locus in case of no steering was investigated on a pastured slope. For the scale model test, the one-fifth model was used, and the running loci in case of steering or no steering were investigated when the model runs on a veneer board covered with vellum paper. Giving the same conditions as the experiment to the theoretical egtation, and using μ=0, 012, the theoretical running locus was determined. It was found that it almost agreed with the experimental running locus.