机械反馈式伺服阀流量测试动态缸参数选用分析

相比电反馈伺服阀动态特性可直接通过阀芯位移响应测试获得,机械反馈式流量伺服阀的动态特性,通常需利用动态缸作为流量传感器间接测量获得。测试结果受动态缸泄漏、阻尼、质量惯性等固有非理想化因素的影响,通常无法准确表达伺服阀本身的性能指标。基于一套实际阀控缸系统,建立Matlab-Simulink仿真模型,解析获得的频带宽结果相比实测结果误差小于0.5 %,由此建立了可准确表达阀与缸性能特性的仿真模型。在此基础上,理论给出了伺服阀本身的频率特性指标,即无泄漏无阻尼及无限刚度动态缸条件下的系统频率特性。以此为依据,分析了实际动态缸活塞质量、活塞粘性阻尼以及泄漏变化情况下,阀控缸系统频率特性偏离理想条件的变化规律。

Analysis and Selection of Dynamic Cylinder Parameters for Mechanical Feedback Servo Valve Flow Test

The dynamic characteristics of the electric feedback servo valve can be obtained directly through the spool displacement response test. But the dynamic characteristics of the mechanical feedback flow servo valve are usually measured indirectly by using the dynamic cylinder as a flow sensor. The test results are affected by inherent non-idealized factors such as dynamic cylinder leakage, damping, and mass inertia, and usually cannot accurately express the performance indicators of the servo valve. Based on a set of actual valve-controlled cylinder system, a Matlab-Simulink simulation model is established. The error of the analytically obtained frequency bandwidth is less than 0.5 % compared with the measured results. Thus, the simulation model can accurately express the performance characteristics of valves and cylinders. The frequency characteristic of the system under the condition of dynamic cylinder without piston mass, viscous damping and leakage is theoretically analyzed. Under the change of the piston mass, viscous damping and leakage, the variation law of the frequency characteristics of the valve-controlled cylinder system is analyzed.