###### Abstract  
Traditional construction machinery's full hydraulic steering system has high energy consumption. An electro-hydraulic flow matching steering system for electric wheel loaders based on closed-circuit pump control is proposed to solve the problem. The transfer function of the electro-hydraulic system is established, and the system is stable according to analysis via Routh matrix. A test platform is built to verify the effectiveness of the system and the control strategy. Taking a 1.6T wheel loader as an example, the energy consumption of the traditional steering system and the new steering system under zero-load, positive-load (shovel loaded with 600 kg gravel), and offset-load (the center of gravity of the gravel is off the center of the bucket) conditions is compared. The results show that the energy consumption of the proposed steering system is greatly reduced compared to the traditional system. Under the condition of zero-load with medium steering speed, compared to the traditional system, consumption is reduced by 22.8%. electric construction machinery; energy saving; steering system; closed-circuit pump-control 2022  
information by combining a linear vehicle model with a steering system model, designing a simple observer to estimate the sideslip during transverse sway rate and steering angle measurements, and developing a state feedback control based on the estimation of sideslip angle to effectively change the vehicle handling characteristics through active steering intervention [13]. The steer-by-wire system cancels the mechanical connection between the steering wheel and the steering actuator, so the driver cannot feel the real road conditions. To solve this problem, scholars had carried out in-depth research and analysis of road sense control theory [14; 15; 16]. [PERSON] et al. studied and designed the fusion algorithm for road feeling control. This is a comprehensive road feeling control strategy including main control and auxiliary control, damping control, and limit control that is proposed based on the direct measurement of steering motor current and vehicle speed, steering handle angle, and other state variables, but no real vehicle detection experiment was carried out [17]. Other scholars have studied the reliability and safety problems of steering-by-wire systems due to structural changes compared to the traditional steering system [18; 19; 20]. However, in the field of construction machinery, the research on steer-by-wire systems is very limited. According to the classification of the hydraulic circuit, the electro-hydraulic steering system of construction machinery can be divided into the open steering system and the closed steering system. To reduce the energy consumption of open systems, several scholars have studied the control of hydraulic valves and hydraulic pumps in the circuit. [PERSON] et al. used pulse-coded modulation to control the low-cost on/off valve group to achieve step-by-step control of the actuator inflow and outflow. An important advantage of this system is its ability to control both the pressure level and speed of the actuator, and the optimization of the pressure level allows the use of lower supply pressures and increases efficiency, but the system still suffers from overflow losses, and the stability or robustness of the system is not analyzed in the paper [21]. [PERSON] et al., proposed a flow-matched steering control method using a servo motor to independently drive a dosing pump, which eliminated overflow losses and reduced the standby energy consumption of the steering system, saving about 16% compared with a load-sensitive steering system, but the system still had a small number of throttling losses [22]. [PERSON] et al., proposed a closed-center electro-hydraulic open steering system, which uses a constant pressure source to independently supply oil to the steering cylinders through four electronically controlled proportional throttle valves.