考虑气穴影响的2D压力伺服阀稳定性

为研究双自由度（2D）压力伺服阀工作时的气穴现象对阀芯稳定性的影响，利用AMESim中的基本库和HCD库建立2D压力伺服阀各组件仿真模型。理论分析得出气穴现象会降低阀体中含气油液的有效体积弹性模量，得出考虑气穴影响的阀芯稳定性条件。仿真结果表明气穴现象会导致主阀芯到达稳定位置后出现振荡现象，影响主阀芯的穿越频率从21 Hz降低至6 Hz，限制主阀芯的频宽，适当增加主阀芯阻尼比能提高主阀芯工作稳定性。提出一种新型阻尼活塞结构，建立模型分析得出其能在不影响伺服阀频响、阀芯位移和抗污染能力情况下提高主阀芯阻尼比以提高阀芯工作稳定性，并且设计实验进行验证。实验结果表明，应用阻尼活塞将2D压力伺服阀压力输出波动从9%降低至2%，能够提高飞行器制动时刹车阀工作稳定性。

Stability of 2D pressure servo valve considering cavitation effect

To study the effect of cavitation on the stability of the spool of a two-degree-of-freedom (2D) pressure servo valve, the simulation models of the components of the 2D pressure servo valve are established by using the basic library and HCD Library of AMESim. The theoretical analysis shows that the cavitation phenomenon will reduce the effective bulk modulus of the gas-containing oil in the valve body, and the condition for the stability of the spool considering the influence of cavitation is obtained. The simulation results show that the cavitation phenomenon will lead to oscillation when the main spool reaches the stable position, which will affect the main spool's crossing frequency from 21 Hz to 6 Hz, limiting the width of the main spool. The proper increase of the damping ratio of the main spool can improve the working stability of the main spool. To solve this problem, a damping piston structure is proposed. The model analysis shows that by improving the damping ratio of the main spool, it can improve the stability of the spool without affecting the frequency response, displacement, and anti-pollution ability of the servo valve. The experimental results show that the the damping piston can reduce the output pressure fluctuation of the 2D pressure servo valve from 9% to 2%, improving the working stability of brake valve during aircraft braking.