Determination of the Position of the Instantaneous Center of Rotation and the Turning Radius When Changing the Track Width of a Wheeled Tractor

Changing the tractor track width significantly expands its functionality and improves its performance properties, but at the same time the rolling conditions of the wheels are significantly disrupted. The relationship between the angles of rotation of the inner and outer steered wheels, which determine the correspondence of each of its values to the condition of ideal rotation, ensuring free rolling of the wheels without slipping, changes when adjusting the track width of a wheeled tractor. Kinematic analysis of the curvilinear movement of the machine when changing the track width allows you to determine the angles of rotation of the wheels corresponding to the actual and correct turn, select the parameters of the steering linkage, and also coordinate the geometry and kinematics of the turning options. Calculated dependencies for studying an ideal turn are widely known, but they are not suitable for a real turn, when the geometry of the steering trapezoid that performs the actual turn is violated. It is shown that the steering linkage can fulfill the conditions for correct rotation of the car only in one of its positions. Analytical dependencies were obtained to determine the position of the instantaneous center of rotation, the theoretical minimum radius and the turning radius of the center of gravity when changing the track width of a wheeled vehicle. The analysis and comparison of the calculation results for the Belarus-80.1 tractor showed, for example, that with an increase in the kingpin track by 0.4 m, the correct turning radii increase by 0.2 m over the entire range of wheel rotation angles. The calculation results proved the need to develop a steering trapezoid design that, when changing the track width, would have an optimal geometry that would allow maintaining kinematic parameters close to the correct turn.