先导流量压差变化-位移校正电液比例阀特性

Characteristics of Electro-hydraulic Proportional Valve with Pilot Pressure Variation-Displacement Adjustment

比例流量阀可根据设定信号连续比例控制执行器的速度或者转速,是重要的电液控制元件,广泛应用于各类电液系统。传统电液比例流量阀为消除负载压力变化对流量的影响,需要采用压差补偿器或流量传感器,增加了阀结构的复杂性和体积,并引起附加的节流损失。针对这些问题,根据Valvistor阀的流量放大特性,提出基于先导流量压差变化-位移校正、主阀流量放大的新型电液比例流量控制原理,该方法根据压力传感器检测的先导阀口压差实时校正先导阀芯位移,并通过主阀线性放大先导阀流量。研究中,建立新型比例流量阀的数学模型,推导得出基于补偿原理的控制策略;进一步建立阀的仿真模型,对比分析补偿前后比例流量阀的静动态特性;设计制造试验样机,通过试验验证了所提原理的可行性。测试结果表明,采用该原理可消除主阀口压差变化对输出流量的影响,动态响应快,特别适用于大流量的电液流量控制。

As an important electro-hydraulic control element,proportional flow valve can continually control the speed or rotation rate of actuators according to the setting signal,which has been widely used in all kinds of electro-hydraulic system.In order to eliminate the influence of variety of load pressure on the flow rate,the traditional electro-hydraulic proportional flow valve needs to use pressure difference compensator or flow sensor,which will increase the complexity of the valve and the volume of valve structure,and cause the additional throttling loss.In order to solve these problems,according to the flow amplification characteristics of Valvistor valve,a new-type proportional control principle based on pressure variation-displacement correction of pilot flow and flow amplification of main valve is proposed.The pilot valve spool displacement is adjusted in real time according to the pressure difference of the pilot valve detected by the pressure sensor according to the method.In this paper,the mathematical model of the new-type proportional flow valve is established,and the control strategy based on compensation principle is derived.Then the simulation model of the valve is established,and the static and dynamic characteristics with and without compensation of the proportional flow valve are analyzed.The test prototype is designed and manufactured,and the feasibility of the proposed method is validated by experiments.The test results show that the proposed principle can eliminate the influence of the variety of main valve port pressure difference on the output flow,the dynamic response is fast,which is especially suitable for the electro-hydraulic flow control in large flow conditions.