三芯随动式矿用高压大流量纯水比例阀特性及控制策略

Hydraulic roof support is the most critical support equipment in the coal mine. Its high pressure and large flow emulsion system, controlled by the on/off valve, has the problems such as the polluted groundwater, uncontrolled flow, inaccurate positioning of hydraulic cylinders and severe pressure shocks, which seriously threaten the environment and the safety of supporting. Realizing water transmission and proportional control of the hydraulic system is an urgent demand in this area. The water proportional valve is the key to achieving this goal. A high pressure and large flow two-position and three-way pure water electro-hydraulic proportional valve based on the three-core following mechanism is invented. However, the physical characteristics of the water, low viscosity, weak lubrication, easy to produce cavitation coupled with high pressure and large flow, make the valve difficult to response fast, stably and precisely. It faces two scientific problems, one is the friction characteristics of the contact seals lubricated by high pressure water, and the other one is the parameters coupling law under time-varying nonlinear disturbance. The intersection of mechanics, fluid, and control is applied to research the three contents of the proportional valve. The project researches the friction force characteristics of the high pressure water proportional valve and its control method, design and coupling of the structural parameter which matches the flow and the dynamic response, and the flow control strategy based on speed/position composite control. The project reveals the coupling law of the flow, pressure, water characteristics, structural parameters and the control parameters. The research results lay a theoretical foundation for the design and prototype development of the high pressure and large flow water proportional valve used in the coal mine.

液压支架是煤矿井下工作面最关键的移动式支护设备，现有的开关式高压大流量乳化液系统存在污染地下水、液压缸定位不准和压力冲击剧烈等突出问题，严重威胁环境和支护安全。实现液压系统纯水化和比例控制是行业迫切需求，水压比例控制阀是实现这一目标的关键，项目发明了一种三芯随动式矿用高压大流量纯水比例方向流量阀。然而，水介质黏性低、润滑性弱、易气化的物理特性及高压、大流量这三重因素的耦合作用，使比例阀在快速、平稳、精准控制方面面临两个科学难题：高压水润滑接触密封方式下的阀芯摩擦特性及控制方法、时变非线性干扰下的参数耦合规律。通过机械、流体、控制等学科交叉融合，研究纯水比例阀阀芯摩擦特性及控制方法、匹配流量和动态响应的结构参数设计与耦合规律、基于速度/位置复合控制的流量调控策略三个内容。揭示流量、压力、水介质特性、结构参数、控制参数之间的耦合规律，从而为矿用高压大流量纯水比例阀的设计和样机研制奠定理论基础。

煤矿综采工作面电液控制系统是以乳化液为传动介质的大流量开关控制系统，在实际使用中，卸载排放和泄漏的乳化液严重污染了地下水资源，大流量开关控制易造成压力冲击破坏及液压缸定位不准确。项目提出采用纯水比例控制技术来解决上述问题，对高压大流量纯水比例阀这一核心控制元件进行研究。发明了三芯随动式纯水比例控制阀，针对该新结构和原理及水介质润滑性弱、易气化等特性，利用理论、仿真与试验相结合的方法对纯水比例阀阀芯摩擦特性及控制方法、匹配流量和动态响应的结构参数与耦合规律、基于速度/位置复合控制的流量调控策略三个内容进行研究。. 首先针对阀芯常用O形、V形、U形圈进行摩擦力试验测试，建立并修正摩擦力理论模型，利用该模型对阀芯沟槽尺寸、粗糙度以及密封材料等参数进行了优化设计。其次，分别对先导阀和主阀阀口进行设计，在探明阀芯液动力、摩擦力等非线性特性的基础上，建立三芯随动式纯水比例阀数学及仿真模型，利用遗传算法对主阀阀口面积梯度、行程、控制腔面积、先导阀阀口面积、阀口压差、开口量及各弹簧、质量、阻尼进行了匹配优化。最后，制造了额定压力为31.5 MPa，流量为1000 L/min，响应频率为2.5 Hz的三芯随动式比例阀原理试验样机，利用试验研究三芯随动机构的位置跟随特性及整阀的流量控制策略，优化了启闭控制曲线。通过研究，项目揭示高压水润滑下的阀芯摩擦特性，获得相应的摩擦控制方法，降低了摩擦力对水压比例阀动静态特性的干扰；获得了阀口及关键结构参数的耦合规律，实现了阀芯的快速平稳运动；探明了先导阀控制速度与主阀动态响应之间的耦合关系及流量调控策略，降低了因阀门快速启闭及负载造成的冲击。项目为矿用高压大流量纯水比例阀的研制与工程应用提供了理论与技术储备，也拓展了水液压的应用场景，促进了水液压的发展与壮大。