A novel assist-steering method with direct yaw moment for distributed-drive articulated heavy vehicle

This paper presents a novel assist-steering method for distributed-drive articulated heavy vehicles (DAHVs) to reduce its dependency on hydraulic steering method and improve the pressure characteristics of hydraulic struts. The objective is to realise the electrification of steering process for DAHVs, which is the basis of unmanned design with more stable control in the following studies. The theory and purpose of the proposed assist-steering method in this paper distinguishes it from the traditional direct yaw-moment control method or assist-steering methods in the previous studies, which easily produce interference with hydraulic steering method in DAHVs during steering process. In this paper, an accurate vehicle model is developed along with the field test for its satisfactory verification. Meanwhile, with the decoupling analyses of two different effects of steering methods on vehicle steering process, the assist-steering method is developed. In order to show the advantages brought on by this method, a case study is performed and analyzed. The results demonstrate that this proposed method can reduce the pressure of hydraulic steering system to about 41.2% without any changes of steering process, which is limited by the drive ability of wheel-side motor. Moreover, the pressure of inlet chamber in hydraulic struts is always reduced to about 40%–60% without any changes of the pressure in outlet chamber, which can improve the working performance of hydraulic steering system.