Journal of Zhejiang University-SCIENCE A

, Volume 20, Issue 3, pp 184–200 | Cite as

Analysis of pressure and flow compound control characteristics of an independent metering hydraulic system based on a two-level fuzzy controller

  • Qi Zhong
  • Bin ZhangEmail author
  • Hui-ming Bao
  • Hao-cen Hong
  • Ji-en Ma
  • Yan Ren
  • Hua-yong Yang
  • Rong-fong Fung


An independent metering valve control hydraulic system (IMVCHS) adopts two independent valves to separately control the meter-in and meter-out orifices. This structure increases the degree of freedom of the control, and improves its flexibility and energy-saving performance. In this study, an IMVCHS was established that applies a control system developed to research the pressure and flow compound control performance. A two-level fuzzy control algorithm based on the calculated flow rate feedback from the spool displacement was proposed to realize high precision flow control, and the two-level fuzzy control algorithm based on the pressure feedback was also adopted to enhance the pressure performance under a dynamic load. A simulation model was established, and its key parameters identified experimentally using the simulated load of a hydraulic bridge circuit. The experimental results show that the proposed flow controller has higher control accuracy with an error of less than 2%, and the flow adjustment time for 40 L/min step control is 320 ms. The pressure controller with a two-level closed-loop fuzzy algorithm can significantly improve these pressure dynamic and static performances, and achieve a step response time of less than 180 ms. Combining the pressure and flow controllers, the pressure and flow compound control of the IMVCHS is realized, and the capacity for coping with load fluctuations is also identified, with compound adjustment times of generally less than 200 ms, and occasionally less than 100 ms. This control system therefore achieves a good performance for pressure and flow compound control, and is able to widen the application of independent metering control technology.

Key words

Independent metering system Pressure and flow compound control Calculation flow rate feedback Fuzzy proportion integral differential (PID) Two-level closed-loop control 

基于两级模糊控制器的独立负载液压系统的压力 流量复合控制特性研究

概 要

目 的

常规负载口独立控制研究多采用商业阀进行, 因 其阀芯位移控制器为封闭式结构, 所以阀芯位移 的动态特性难以调整, 进而影响了系统的压力和 流量控制性能。本文旨在探讨负载口独立控制系 统中阀芯位移特性对系统压力和流量控制的影 响, 并研究提高系统压力和流量控制性能的方 法。


1. 设计基于两级模糊比例积分微分(PID)的压 力和流量控制器; 2. 设计基于阀芯位移反馈的流 量控制器; 3. 建立试验模型, 成功实现液压系统 高动态压力流量复合控制。

方 法

1. 通过理论分析得到影响系统压力和流量的关键 因素(公式(9)和(13)); 2. 提出位移控制为 内环、压力和流量控制为外环的两级模糊PID 控 制算法, 并开发相应的控制系统(图2~4); 3. 通 过仿真和实验分析, 验证本文提出的控制器所具 有的阀芯位移、系统压力和流量的控制效果(图 13~18)。

结 论

1. 两级模糊PID 控制器具有较好的系统压力和流 量控制效果; 2. 基于阀芯位移反馈的流量控制器 具有较高的流量控制精度; 3. 运用本文设计的可 编程控制系统进行液压系统的压力流量复合控 制, 稳定时间小于200 ms, 使系统动态特性得到 提高。


独立负载系统 压力流量复合控制 计算流量反 馈 模糊PID 两级闭环控制 

CLC number



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Copyright information

© Zhejiang University and Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.State Key Laboratory of Fluid Power and Mechatronic SystemsZhejiang UniversityHangzhouChina
  2. 2.Department of Mechanical and Automation EngineeringKaohsiung First University of Science and TechnologyKaohsiungChina
  3. 3.College of Mechanical and Electrical EngineeringWenzhou UniversityWenzhouChina

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