Study on the Influence of Dynamic Characteristics of Servo Valve on Coupling Vibration of Cold Rolling Mill

The cold rolling mills are complex electro-hydro-mechanical systems in which vibrations are usually detected as issues during production process. In the present work, the vibrations with frequencies of 80Hz were found at top of the rolling mill and the pressure behind servo valve during the production process. In order to understand the vibration mechanism and to explore the measurements for vibration suppression, the dynamic models were proposed to describe valve spool, 8-DOF cold rolling mill, and hydraulic system based on the dynamic characteristics of servo-valve. The analytical solutions and numerical solutions were obtained for the vibration rules for the valve spool displacement and the output flow rate under different working conditions. Moreover, the influence of dynamic characteristics of servo-valve on the vibrations and optimization of the servo-valve were discussed. The results suggest that the dynamic characteristics of servo-valve have a significant influence on the hydro-mechanical coupled vibration of rolling mill and the vibrations can be dampened by improving the dynamic characteristics of rolling mill. This work is expected to provide a new perspective to suppress the hydro-mechanical coupled vibrations.