This Ph.D. thesis is focused on tensile forces measurement process of modern tillage machines for bigger working width. There is a limited amount of measuring devices for tensile forces higher than 100 kN.To eliminate tensile rod disadvantages (need of use of two tractors is complicated for measuring operation during the headlands turns) the new measuring frame was developed to measure the tensile forces. To characterize the physical attributes of the soil, before the new developed measurement, the samples of unbroken soil where taken (Kopecky cylinders. The penetration resistance of soil was measured in a horizontal and vertical profile by use of penetrometer.The measuring made on specific lands proven the new developed measuring device to be able to measure the tensile force up to 200 kN and more. The practical use of the measuring device was comparable to the measuring by a tensile rod during the measuring process.The considerable influence of the soil moisture was proven by the penetration measurements of the soil. The vertical and horizontal penetrometer measurements showed a similarity of the measuring method. The horizontal penetrometer might be a useful measuring method for a quick analysis of soil physical character considering accurate soil moisture measuring. Accurate instant soil moisture measuring and precise measurement of chisel plough working depth is a current theme for a future research.

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The numerical simulation of the tree pulling test was carried out in the thesis. ANSYS Parametric Design Language was used for the simulation. The parametric design enables use of simulation for variations of tree dimensions, material properties and device positions. Results from numerical solution were compared with a field experiment and analytical solution in cases of three oaks. To found significant influence of input parameters probabilistic analysis was carried out. The analysis found that there is a significant correlation among stem diameter, root volume and tree inclination and nodes displacement on the tree stem. The influence of stem defect and root-plate damage on ability of devices was found as well. Numerical model can be used for the simulation of tree pulling test in wide variety of different configurations, for example change of geometry, material properties and defects extension and position of stem and root-plate system. The practical impact of results and further development of numerical simulation are discussed at the end.

The aim of this PhD thesis was to analysis laboratory and field measurements tractors with different chassis designs. For the measurements were used John Deere tractors with name 8320R if a wheel and if 8320RT crawler tractor, possessing the same engine power. Before the field measurements were conducted laboratory tests of tractors, which resulted was the compilation of the full speed characteristics. The field measurements were focused on identifying characteristics of tensile test tractors. For wheeled tractor were also measured differences tensile characteristics when changing inflation pressure. Subsequent comprehensive part of a field measurement looked at the analysis of data obtained from measurements of performance and energy parameters of tractor kits depending on the operating mode of the engine. From the experimental measurements show that the tractor equipped with a belt chassis design has a higher tensile strength and also has a lower specific consumption and slippage than wheeled tractor. When comparing the measured data with different wheeled tractor tire inflation pressure, we find that reducing inflation pressure has a positive effect on the change of the tensile characteristics. In the practical part of the measurements we have identified that tracked tractor achieves higher performance and lower energy intensity than the wheeled tractor. It was also shown that by adjusting the engine speed into so called economic areas can improve performance while reducing fuel consumption tractor sets.

The aim of the thesis was to prepare a list of structures, used in tractors, with a focus on the chassis and axle types.Another point was to characterize the methodology for measuring the tensile properties of the concrete surface, which carries out the state testing laboratory in Nebraska.Further develop methodologies terrain measurement of tensile properties.After this, tabular and graphical data obtained from the state testing laboratory, which concerned wheeled and caterpillar tractor Challenger, where the issue of tensile properties was solved, have been processed. The terrain measurements on the stubble were chosen two tractors John Deere 8320R wheeled and caterpillar 8320RT. The measurement was focused on differences in tensile properties depending on the kind of the tractor chassis. From the analysis of the measured values shows that the caterpillar tractor has higher values of tensile properties in the measurement of on the concrete surface and on the stubble. The difference is caused by different contact surface of the chassis unit. On soft stubble there are differences in tensile properties pronounced because of deformation of the base. It is proven that we can achieve higher efficiencies of work with tracked tractor and with the fact lower fuel consumption because of better transmission of engine power.

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