基于Simulink模型的先导式溢流阀动态特性仿真方法

Simulation Method of Pilot Relief Valve Dynamic Characteristic Based on Simulink Model

以三节同心溢流阀为例研究先导式溢流阀动态特性的仿真方法,首先以反推(用p求q)法求解溢流阀静态特性方程组,计算出溢流阀工作点结构参数,然后以溢流阀动态特性方程组构建了Simulink模型。通过仿真得到了以流量为阶跃输入信号、以响应压力为输出信号的理论曲线。仿真结果表明溢流阀动态响应特性的决定因素不是阀芯和弹簧构成的二阶环节,而是主阀上、下腔的液容容积和固定阻尼器直径。上腔容积主要决定响应曲线的超调量,下腔容积主要决定响应曲线的时间;在仅减小固定阻尼器直径其它参数不变的情况下,超调量Mp降低和调整时间ts延长。实验结果证明,结构参数模型法仿真曲线和实验结果曲线基本一致,为液压系统性能研究提供了可行方法。

Taking the three stage homocentric pilot as an example, the method of a pilot relief valve dynamic characteristic simulation was researched. The equations set of dynamic characteristic were derived according to its feature in which the steady-state fluid force of valve core was considered in mathematical equations. Firstly structure parameters were computed by using reverse derivation fixed-point it- eration method to calculate pilot relief valve statistic property equations while setting the twenty percent working pressure as a starting point; secondly the simulation of pilot relief valve simulink model was built based on the pilot relief valve dynamic characteristic equations. The theoretical curve of the output pressure response was carried out by means of the simulation model with the flow step input signal. The simulation results indicated that the decisive factor of pilot relief valve dynamic characteristic is not two order oscillation element consisting of valve core and spring but the bulbs volume of valve cavity, and fixed damper diameter. The overshoot of pressure response curve was determined by upper chamber, and lower chamber influenced the response time. If only reducing the fixed damper diameter but other parameters not changed the overshoot Mp could be decreased and adjustment time ts could be extended. The experiment result was consistent with the structure parameters simulation results. This method provided a practical approach for hydraulic system research.