Given the crossing-obstacle problems of wheeled vehicle on soft beaches, the changing rules with driving speeds of the crossing-obstacle ability of wheeled vehicle, soil moisture content, and soil type on soft beach ground were innovatively studied in this paper, with the hook traction force taken as the evaluating index. It showed that the RMS values of wheeled vehicle hook traction force, which was 9484N at 5 km/h and 8859N at 20 km/h, decreased with the increase in driving speed when the wheeled vehicle crossed the horizontal ditch. It collected soft beach ground soil samples and tested the parameters of mechanical properties. By considering specific structural parameters of the wheeled vehicle, this paper constructed the simulating model of the crossing obstacle ability of wheeled vehicle on the soft beach, analyzed the differences between the simulation and test result through full-scale vehicle tests. It discussed the influential factors of the crossing obstacle ability of wheeled vehicle on soft beach ground, indicated that the crossing obstacle ability of wheeled vehicle on soft beach increased with the increase of equipment's driving speed and soil moisture content. This paper creatively proposed a method to evaluate the equipment's off-road trafficability based on the combination of soil in-situ collection, soil tank test, dynamic simulation and experimental verification, and proposed the influencing factors and changing rules of equipment's off-road trafficability on soft beach ground, which laid a theoretical foundation for the research on the off-road trafficability of wheeled vehicle.

The development of restoration technology and meadows, improvement of run-down pastures, and productivity improvement of old crops of perennial grasses is an urgent problem in agriculture. The tillage traction force in seeder designing and manufacturing is an important indicator of energy efficiency. The objective of this work is to reduce traction force and ensure seeding depth uniformity by justifying the optimal chisel parameters of a grain-fertilizer-grass seeder for direct seeding in sod. The Box-Behnken method was applied to investigate the traction force dependence on the seeder velocity, seed embedding depth, chisel width, and mounting angle. The obtained optimal parameters of coulters were justified by the finite element method. Structural and technological parameters were checked using the smoothed-particle hydrodynamics method on the deformation and wear of the seeder working body. The revealed optimal coulter parameters were as follows: chisel width was 20-20.97 mm, chisel length was 145-148.9 mm, mounting angle was 75 degrees-81.6 degrees, and achieved minimum traction force was 720 N. These parameters ensure the quality of grass seed embedding in the sod. The theoretical data of traction force (8.27-8.39 kN) are in accordance with the experimental (8.28-8.63 kN) data under field conditions. These findings are efficient in agrotechnical and mechanical predictions regarding the occurrence of chisel residual stresses and the working lifetime of the part.

Determination of the traction forces between the tractor and its implement is important due to optimal utilization of tractor power and its connected implement, estimation of soil properties or strength, and fatigue studies. The working width of agriculture implements is increasing, which demands higher traction forces. The article presents the design and test in-field measurement of a double-frame dynamometer for the three-point hitch of the tractors, which can measure forces up to 400 kN. The dynamometer is equipped with six force transducers positioned so that force measurement on all axes is possible. The connection of the dynamometer follows the standard ISO 730. The design of the dynamometer and force calculations are presented. The in-field measurement was performed using disc and chisel tillage implements at different tillage depths. The increasing magnitude of the resultant traction force with increasing tillage depth and the effect of the geometry of tillage machines were found.