Accurate posture control of hydraulic roof supports, which use pressurized water as their fluid power source, is an important part and research direction of intelligent fully mechanized mining face. At present, the large flow on/off directional valve used on the hydraulic roof support cannot meet the requirement of precise posture control of the roof support. To overcome the conundrum, a novel two-position three-way electro-hydraulic proportional directional flow valve for hydraulic roof support is proposed. The new valve contains two pilot stages and two main spools. The two pilot stages cooperate with each other to control the movement of the two main valve spools, which are the inlet valve spool and the outlet valve spool. The inlet valve spool adopts the Valvistor principle. The valve can realize manual pilot control and electro-hydraulic proportional flow control of the passage P-A, which has been verified by a simulation model. In this paper, the static and dynamic mathematical models of the new proportional valve are established, and the key parameters affecting the valve performances are analyzed and verified by the simulation model. An optimization control scheme is proposed to overcome the influence of supply pressure, P-A pressure difference, and nonlinear interference force on steady-state displacement and response speed of the valve. The results show that this optimization method can significantly improve the response speed of the spool and promote the linearity of spool displacement under a slope signal. In addition, the fluctuation of chamber pressure and spool displacement caused by the discontinuous flow of a fast switching valve is systematically analyzed. The analysis shows that increasing pulse-width modulation carrier frequency is an effective way to reduce fluctuation amplitude. The research provides a new design idea and control method for an electro-hydraulic proportional directional valve of hydraulic roof support.

以加压水为流体动力源的液压顶板支架姿态精确控制是智能综采工作面的重要组成部分和研究方向。目前，液压顶板支架上使用的大流量开/关换向阀不能满足顶板支架姿态精确控制的要求。为了克服这个难题，提出了一种用于液压顶板支架的新型两位三通电液比例方向流量阀。新阀门包含两个先导级和两个主阀芯。两个先导级相互配合，控制两个主阀芯的运动，即入口阀芯和出口阀芯。进口阀芯采用Valvistor原理。该阀可实现通道PA的手动先导控制和电液比例流量控制，经仿真模型验证。本文建立了新型比例阀的静态和动态数学模型，并通过仿真模型对影响阀门性能的关键参数进行了分析和验证。提出了一种优化控制方案，以克服供给压力、PA压差和非线性干扰力对阀门稳态位移和响应速度的影响。结果表明，该优化方法可以显着提高阀芯的响应速度，提升在斜率信号下阀芯位移的线性度。此外，系统分析了快速切换阀不连续流动引起的腔室压力和阀芯位移的波动。分析表明，提高脉宽调制载波频率是降低波动幅度的有效途径。该研究为液压顶板支架电液比例换向阀提供了一种新的设计思路和控制方法。