Automatic control system of a rear-wheel drive vehicle moving on a sloped weak sandy terrain

The general mechanism of tractive performance of a four-wheel vehicle with rear-wheel drive moving up and down a sloped sandy soil has been considered theoretically. For the given vehicle dimensions and terrain-wheel system constants, the relationships among the effective tractive or braking effort of the vehicle, the amount of sinkage of the front and rear wheels, and the slip ratio were analysed by simulation. The optimum eccentricity of the vehicle's center of gravity and the optimum application height of the drawbar-pull for obtaining the largest value of maximum effective tractive or braking effort could be calculated by means of the analytical simulation program. For a 5.88 kN weight vehicle, it was found that the optimum eccentricity of the center of gravity e(opt) was 1/6 for the range of slope angle - 0 less than or equal to beta less than or equal to pi /24 rad during driving action of the rear wheel and e(opt) was also 1/6 for the range of slope angle-pi /24 less than or equal to beta less than or equal to0 rad during braking action of the rear wheel.: The optimum application height H-opt was found to be 35 cm for the range of slope angle 0 less than or equal to beta less than or equal to pi /24 rad during driving action of the rear wheel and H-opt was 0 cm for the range of slope angle-pi /24 less than or equal to beta less than or equal to0 rad during braking action of the rear wheel. (C) 1998 ISTVS. All rights reserved.