SPATIAL MODEL FOR DETERMINING THE STEERING GEAR RATIO

Abstract

The most important vehicle properties that are affected by the quality of steering design are agility, handling and stability. Maneuverability is characterized by curvilinear movement with small turning radii at low speed, while controllability and stability are manifested mainly during emergency maneuvers at high speed. High maneuverability is important in difficult urban conditions, when driving in heavy traffic and when parking. The maneuverability of special-purpose vehicles is characterized by such parameters as the minimum deviation of the trajectories of the main point of the tractor and the characteristic point of the semi-trailer, the minimum turning radius and the width of the lane. The controllability and stability of special-purpose articulated vehicles substantially depends on the law of steering the wheels of the trailer link. Steering angles also have a significant impact on handling. Prediction of the listed properties depends on the steering parameters, in particular, on its gear ratio. At the same time, the layout of special-purpose tractors assumes the location of the cab in front of the front axle, therefore, the steering drive includes a steering mechanism with an output link of a rotary type and a longitudinal rod connecting the bipod with the swivel arm of the front left wheel. Steering control design provides for kinematic, power, dynamic and strength types of calculation, as well as calculation of the amplifier, if available. Traditionally, the determination of the gear ratio is carried out within the framework of kinematic and dynamic calculations by the geometric, vector or analytical method. However, all three methods are rather laborious and have low accuracy, especially when solving a spatial problem. In this study, the author has developed a coordinate-iterative method for selecting the parameters of the steering drive and calculating the angles of rotation of the steered wheels in a three-dimensional coordinate system.