Two-stage directional valves usually employ proportional pilot control technology, which has the disadvantages of dead zones, leakage, and the large moving mass of the pilot valve. It is difficult, therefore, to achieve fast-response performance of the main valve. In order to overcome this problem, a switching pilot technology that employs two independent high-speed on/off valves (HSVs) is proposed to replace the traditional pilot proportional valve. Due to the rapid switching characteristics of HSVs, the dead zone of the pilot stage is avoided, and the dynamic response performance of the main valve is improved. The experiments indicate that the switching frequency of the pilot HSVs and supply pressure of the pilot stage have a very large effect on the dynamic performance and control accuracy of the main valve. Increasing the switching frequency of the pilot HSVs is helpful for improving main-valve control accuracy. The larger supply pressure of the pilot stage can achieve a faster dynamic performance of the main valve while causing larger static errors. The results show that the switching pilot technology can clearly improve the static and dynamic performances of the main valve. With the increase of pilot supply pressure, the step rise time is reduced from 21.4 ms to 16.8 ms, and the dynamic performance of the main valve is improved by 21.5％. With the increase of pilot switching frequency, the steady-state error decreases from 24 μm to 20 μm, and the control accuracy of the main valve is improved by 16.7％.

Qi ZHONG;En-guang XU;Ti-wei JIA;Hua-yong YANG;Bin ZHANG;Yan-biao LI

College of Mechanical Engineering,Zhejiang University of Technology,Hangzhou 310023,China;State Key Laboratory of Fluid Power and Mechatronic Systems,Zhejiang University,Hangzhou 310027,China;Key Laboratory of Special Purpose Equipment and Advanced Processing Technology,Ministry of Education and Zhejiang Province,Zhejiang University of Technology,Hangzhou 310023,China

浙江大学学报（英文版）（A辑：应用物理和工程）

[1]Qi ZHONG;En-guang XU;Ti-wei JIA;Hua-yong YANG;Bin ZHANG;Yan-biao LI-.Dynamic performance and control accuracy of a novel proportional valve with a switching technology-controlled pilot stage)[J].浙江大学学报（英文版）（A辑：应用物理和工程）,2022(04):272-285

HSVs

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