The results of a theoretical analysis are presented to assess the influence of the longitudinal base and track of a tractor with all steerable wheels on its basic geometric and kinematic characteristics in curved motion, characterizing its maneuverability. The maximum abscissa and ordinate of the trajectory of the entrance to the turn and the minimum theoretical radius of the steady-state stage of a circular loop-free turn are taken as estimated indicators. A comparison is given with the calculation results obtained in the study of a tractor with front steerable wheels under identical design parameters and operating conditions. To determine the necessary desired parameters describing the trajectory of the curved movement of the tractor, parametric equations are obtained. Analysis of the calculation results showed that with an alternate increase in the length of the longitudinal base from 2.2 m to 3.0 m and the track width from 1.2 m to 2.2 m, with the remaining unchanged design and operational characteristics, the minimum radius increases, respectively, by 18.5% and 16.3%, and the maximum ordinate of the trajectory of entry into the turn – by 3.9% and 16.6 %, while the maximum abscissa of this section of the trajectory decreases by 20.4 % and 40.4%. A comparison of the turning method, which is the subject of research in this paper, with the method of turning the front steerable wheels, all other things being equal, showed the effectiveness of the first of them. An increase in the maximum abscissa by 1.75 times was revealed, but a decrease in the maximum ordinate by 1.05 times and the minimum turning radius by 1.69 times. This gives reason to talk about the best maneuverability of a tractor with all steerable wheels.
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