Application research of electro-hydraulic servo steering system based on independent metering system

Abstract

Electro-hydraulic servo steering system (EHSSS) is a key technology for heavy vehicles. The traditional EHSSS has high control accuracy but low energy efficiency. Therefore, this paper proposes a novel EHSSS based on independent metering system, which can combine high steering accuracy with high energy efficiency. Firstly, two servo-proportional valves are used to reduce the throttling loss at the meter-out orifice. The servo motor pump is used to keep the pump supply pressure at a low value. Then, to ensure high steering accuracy, a position-velocity-pressure combined control strategy is proposed for easy engineering practice. And a smooth switching strategy is proposed to achieve smooth mode switching at high frequency. Finally, the effectiveness of the proposed method is verified by experiments. The experimental comparison results show that the proposed method can achieve the same accuracy as the valve-controlled steering system with less energy, and can realize smooth mode switching.

Active Disturbance Rejection Decoupling Control for Independent-Metering Electro-Hydraulic System With Online Compensation Information

“…Eq. (11) reveals that the first term on the right side of the equation is the cylinder dynamic change caused by the calculated flow rate of the nominal valve of pressure drop, the second term is the cylinder dynamic change caused by the deviation of nominal calculated flow rate from actual calculated flow rate, the third term is the cylinder dynamic change caused by the flow rate into the rodless chamber of the cylinder, and the fourth term is the cylinder dynamic change caused by the pressure control subsystem, the unmodeled part and the load disturbance. If the second to fourth terms are treated as the total disturbance, which is observed and compensated by ESO, it significantly increases the amount of total disturbance that the ESO needs to estimate.…”

“…Ziqi Liu designed a independentmetering system for hydraulic hexapod robot, and developed a sliding mode repetitive controller for it to get better control performance and energy-saving effect [10]. Aiming at independent metering hydraulic steering system, Qihui Liu designed a combined control strategy based on the position, velocity and pressure of the system to ensure the steering accuracy and achieve the purpose of energy saving [11]. Although some scholars have already studied IMEHS and achieved some results, many advanced control algorithms based on mathematical models are difficult to be widely used in industry which is due to the fact that the hydraulic system is nonlinear and time-varying, and the system is difficult to be represented by an accurate mathematical model [12].…”

Research on Design and Control Strategy of Novel Independent Metering System

“…Abuowd et al [3] designed a stepped rotary flow control valve and proposed the use of four flow control valves to form an independent metering system, and investigated its system char acteristics. Liu et al [4] proposed the independent metering system composed of two The research on the independent metering system by domestic and foreign researchers has placed a major focus on the hydraulic system and different control strategies of the combination design of multiple hydraulic valves to improve the energy-saving characteristics of the system.…”

“…Abuowda et al [3] designed a stepped rotary flow control valve and proposed the use of four flow control valves to form an independent metering system, and investigated its system characteristics. Liu et al [4] proposed the independent metering system composed of two servo valves and applied it to the electro-hydraulic steering system (EHSS). The energy saving and response characteristics of the system were proved by experimental research.…”