Hybrid Steering Systems for Automotive Applications

The paper presents the results of the researches performed in order to find out the static and dynamic performances of some recent types of hybrid electrohydraulic servomechanisms. The new concept was generated by the needs of the modern aerospace technology called “flight by wire”, directed to the use of compact actuators composed mainly by a brushless motor driving a hydrostatic pump connected in a close loop with a hydraulic cylinder. The numerical simulations performed with Simcenter Amesim language pointed out the possibility of saving a lot of energy with this new concept, already used on civil airplanes and fighters. The new wave of autonomous driving generated a lot of combinations of electric and hydraulic components, according the peculiarities of applications. The authors studied the accuracy of the hybrid steering system of an articulated tractor based on a digital industrial servo valve combined with an ORBITROL standard unit. The structure of the last generation of the trucks hybrid steering systems was also studied, taking into account the real performances of each component. Finally, the effect of the strong penetration of the hybrid servo systems in the automotive manufacturing systems is assessed.