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

Abstract:

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.

Key words:hydraulic transmission;dynamic cylinder;mechanical feedback servo valve;flow test;dynamic characteristics