ESTIMATION OF THE PARAMETERS OF THE TRAJECTORY OF THE ENTRANCE TO THE TURN OF THE WHEELED VEHICLE DURING THE CORRECT AND ACTUAL TURN

The trajectory of a wheeled vehicle was estimated for the purpose of selecting rational operational characteristics of a wheeled vehicle during curvilinear motion. The current coordinates of the kinematic center of mass of a wheeled vehicle were determined in two ways using formulas for determining the minimum theoretical radius: of the correct and actual turn performed by a wheeled vehicle equipped with a four-link solid rear-mounted steering trapezoid. Dependencies for determining the current coordinates of the kinematic center of mass of a wheeled vehicle for the correct and actual turn, allowing for the selection of kinematic characteristics of the turn of a two-axle wheeled vehicle with front steered wheels, were presented. The basis was a comparison of the parameters of the curved trajectories of entering the correct and actual turn. When calculating the trajectory coordinates, it was assumed that there is no lateral slip of the wheels and no slip of the vehicle in the lateral direction, the forward motion speed and the angular velocity of rotation of the steered wheels are constant. The angle of rotation of the steered wheel is specified by a linear function of time. The calculation results showed that at the end of the turn entry section, the value of the trajectory curvature radius for the actual turn is greater than that for the correct turn (the discrepancy is 3.78%). On the one hand, this indicates a deterioration in maneuverability, on the other hand, it follows that the instantaneous turning center lies behind the wheelbase of the vehicle, which in real operating conditions leads to kinematic misalignment in turning of all wheels, lateral deformation of tires, lateral slip and wear. At the end of the turn entry section, the value of the trajectory inclination angle to the ordinate axis for the actual turn is greater than that for the correct turn. Consequently, during the actual turn, the vehicle is in more favorable conditions for entering the section of the established turn.