插装式二维(2D)伺服阀的理论分析与实验研究

Theoretical analysis and experimental study on two-dimensional cartridge servo valve

针对传统伺服阀导控级和功率级平行放置而无法实现插装的问题,研究了一种新型的插装式二维(2D)伺服阀,其特点在于:先导级和功率级集成在单个具有双自由度的阀芯上;力矩马达与阀芯同轴连接,并安装在阀芯末端。通过力矩马达直接驱动阀芯转动,然后利用伺服螺旋机构放大功率并驱动阀芯直线运动,从而控制输出流量。同时可以采用直线位移传感器(LVDT)进行检测阀芯位移,实现位置闭环控制以提高阀的控制性能。为了探究其开环特性,首先建立力矩马达和2D阀的数学模型,求得其开环传递函数;然后,通过仿真了解关键参数对系统动态响应的影响;最后,进行实验研究,验证该阀设计的可行性。实验表明,在满量程输入的情况下,该阀开环时滞环为5%,分辨率≤1%,响应时间为10ms,动态频响为35Hz;闭环下性能显著提高。插装式2D伺服阀结构简单,尺寸小,质量轻,响应快和控制精度高,在航空航天及军工领域有广阔的应用前景。

Since the conventional servo valve’s pilot stage and power stage are in parallel placement and could not realize cartridge,a new type of two-dimensional(2 D)cartridge servo valve is studied.Its pilot stage and power stage are integrated in the two degrees of freedom of the 2 Dspool and the torque motor is mounted coaxially with the spool at the end of the spool.To control the output flow of the servo valve,the rotational motion of the spool is driven directly by the torque motor,and then the power is amplified and the straight motion of the spool is driven by the servo screw mechanism.To improve valve’s control performance,the closed loop control of the spool is realized by detecting the displacement of the spool by Linear Variable Differential Transformer(LVDT).To explore its open-loop characteristics,the mathematical models for the torque motor and 2 Dvalve are established,computing their transfer function.Then the effects of the key parameters on the valve’s dynamic characteristics are simulated and analyzed.Finally,an experiment is carried out to verify the feasibility of the valve design.The experimental results show that under the open-loop control,the hysteresis loop of the valve is about5%;the resolution is not more than 1%;the rising time of step response is about 10 ms;and the frequency width is approximately 35 Hz at full-scale input,significantly improving the performance under close-loop condition.It is concluded that the2 Dcartridge servo valve has a simple structure,small size,light weight,fast response,and high control accuracy,showing broad applicability in aerospace and aeronautics industries.