Scientific paper ID 1942 : 2020/3

The development of the steering system constructions of modern vehicles is aimed at increasing their adaptability and optimizing the dynamics of movement, i.e. the ability to change their parameters depending on the driver actions and road conditions. Earlier the presence of an actuator in the steering system was determined by the sanitary ments and norms for limiting the force applied to the steering wheel while turning the steered wheels with maximum resistance (turning in place). Recently the replacement of the traditional hydraulic actuators in the steering systems with electric ones was imposed by the increasing ments for driving adaptability, comfortability, and car safety.

The study proposes an algorithm for calculating some input parameters necessary to select the technical characteristics of an electric motor for an actuator in a car steering system. The essence of the method is to determine sequentially the resistances acting on the steered wheels of the vehicle when making a turn. In order to achieve this goal diagrams of a steerable wheel in a state of turning with the forces acting on it and accelerations have been shown. On the basis of the kinetic energy of the considered mechanical system, an equation of power balance has been obtained. Dependencies for determination of the torque of a stepper motor built as an actuator in a car steering systems with screw-and-nut and rack-and-pinion steering mechanisms have been derived. The presented approach herein could be applied in practice and in the process of learning the design of actuators as a part of the automotive steering system.