Abstract
The steering and wheel suspention system design should be customized for automated control action. In this case, the ability to create a carrying and propelling module as part of the wheel, wheel suspension and wheel turning system for nonlinear motion is of paramount importance. Among all the existing technical solutions, electro-hydraulic drives can best meet this requirement. Wheel steering issues involve active safety, improvement of vehicle running smoothness (vibration protection) and are priority areas of the vehicle theory [1-8]. Engineers and scientists exert a lot of efforts for construction and design of adaptive springing [8, 9] and steering systems [10]. It is proved that steering systems should be integrated with automatic suspension control. The paper [11] states, that these issues are related to functional problems of active vehicle safety. The paper [12] addresses integration of steering, active suspension and braking control systems. These are well-known ABS, PBS, EBD and ESP as well as EBS and RSP systems. Their modular concept enables a significant reduction of development and production costs and improved field maintenance efficiency. This results in improved engineered vehicle efficiency [13-15]. The papers [16-18] provide a general overview of the combined effect of steering and springing components of the follow-up control system on the wheel and vehicle dynamics. The selection of the electro-hydraulic drive executive elements (actuators) structural scheme is a challenging task for the designer. This topic has not been covered in scientific and technical papers as applied to the vehicle wheel module. The paper presents analysis results for several actuator options. It contains recommendations and basic calculations for an efficient scheme of hydraulic actuators of the vehicle steering system with vertical wheel loads from 50.9 kN to 70.0 kN. The system of hydraulic actuators should turn the wheel according to the control signal set by the driver or automatic driving system. The steering rate at 1.35 to 4.5 kNm torque in the wheel contact area shall be within 0.35 to 0.40 rad/s. This requirement is inherent in the road safety requirements. The paper considers four options of the vehicle wheel steering architecture.