A new hydraulic synchronous scheme in open-loop control: Load-sensing synchronous control

Haigang Ding,Yanbin Zhao,Yongzhuang Liu

doi:10.1177/0020294019896000

Haigang Ding, Yanbin Zhao + Show 1 more

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https://doi.org/10.1177/0020294019896000

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Abstract

At present, open-loop synchronous control for hydraulic systems widely using synchronous valves has low synchronous accuracy due to weak anti-bias capacity, and is hard to adjust synchronization velocity, so it could not meet the requirements of accurate synchronization under severe conditions. In this paper, a load-sensing synchronous control is developed to obtain accurate synchronization in open-loop control, which is made up of a load-sensing unit and a synchronous valve. In the load-sensing loop, a load-sensing pump supplies pressure and flow required by the system through pressure closed-loop control, and a load-sensing valve could improve the capability of anti-offset loads by pressure compensation. The synchronous valve is between the load-sensing pump and load-sensing valve, to achieve equal distribution of flow supplied by the pump, which could improve the divider accuracy of the load-sensing system. A test system within load-sensing synchronous control is established, and then comparison experiments under different partial loads are carried out. The experimental results show that, compared with the traditional synchronous valve control, the load-sensing synchronous control has the advantages of higher synchronous precision, higher energy efficiency and also the ability of velocity regulation. Load-sensing synchronous control has the potential of high precision synchronization control in server environments.

Highlights

Synchronization drive[1,2] refers to two or more actuators driving a load at the same speed
In order to overcome above shortcomings of openloop synchronous control, we propose a new synchronous control scheme, load-sensing synchronous control (LSSC) and explain its structure and principle in detail, and establish a test system to test its synchronous performances, and the comparison experimental results verify the new control scheme
Experimental results show that, for both LSSC and synchronous valve control (SVC), larger offset load will lead larger synchronous deviation; compared with SVC, LSSC has higher synchronous accuracy under partial loads, and its deviation is less than 1%, because LSSC has stronger ability to resist partial loads due to the pressure compensation function of LS valves

Summary

Introduction

Synchronization drive[1,2] refers to two or more actuators driving a load at the same speed. The LS pump supplies pressure and flow according to load demand by pressure closed-loop control, which could improve the system efficiency;[20,21] the LS valve is used to regulate the velocity of actuators by adjusting its opening. The synchronous valve establishes the dynamic relationship between two load-sensing branches, which can improve the synchronization accuracy This control scheme integrates the advantages of synchronous valve control (SVC) and load-sensitive control, and has following advantages: strong anti-bias ability under open-loop control, high synchronization accuracy, high efficiency and the capacity of velocity regulation. There is no synchronous valve in excavators, but a synchronous valve is mounted between the LS pump and LS valves in LSSC system; the synchronous valve establishes a flow relationship of two branches, which could improve the synchronization accuracy of two actuators.

Experiments and analysis

Findings

Conclusion