Analysis and comparison of dynamic characteristics of hydraulic leveler servo system

A hydraulic servo system was designed for the full hydraulic hot leveler according to the straightening principle and the processing requirements.The straightening of plate was realized by control of the displacement of the unsymmetrical cylinder with application of the unsymmetrical servo valve and the displacement sensor.By solving the transfer functions of the unsymmetrical valve to control the unsymmetrical hydraulic cylinder and the constant back-pressure cylinder system,both position control effects of the hydraulic cylinder were analyzed by the simulation software Hyvos.It was found that the former control is obviously better than latter.The hydraulic cylinder position control precision and the plate workpiece straightness obtained in the production prototype validated the designed system.The results provide a guide for the design,simulation and control of the unsymmetrical hydraulic cylinder controlled by the unsymmetrical valve.