Research on energy saving and control characteristics of back pressure controllable variable speed pump controlled steering system for heavy vehicles

Steering system of heavy vehicle facing intelligent and green development needs to satisfy the requirements of high precision and energy-efficient dynamic steering. Traditional steering systems use valved servo systems, which offer high steering accuracy but result in significant energy dissipation at the valve ports. In contrast, the variable speed pump control system (VSPCS) realizes the precise servo of steering system through direct volume control, which basically eliminates the energy dissipation at the valve port. However, the VSPCS lacks sufficient system stiffness due to low back pressure, making it difficult to achieve precise steering. To address these limitations, this paper proposes a back pressure controllable variable speed pump controlled steering system scheme (BCVSPCSS), which combines the energy-efficient flow supply of the VSPCS with a servo-proportional valve is used for back pressure control to, improving the dynamic performance of the system. This integration allows for precise steering while maintaining energy efficiency; The design of a dual objective nonlinear control strategy for angle and back pressure is crucial to deal with uncertainty and nonlinearity in the system. The Lyapunov analysis shows that the closed-loop system has asymptotic stability. In this paper, the experimental bench of BCVSPCSS is built for experimental verification. The results show that back pressure control effectively enhances the system’s immunity. Under the same working conditions, the maximum angle error of the two systems is roughly the same, both around 1°, while the energy consumption of BCVSPCSS is reduced by about 84.6% compared to the valve controlled steering system.