| Looper is driven by a hydraulic system in the strip hot rolling system,but the time of its use is not long in domestic application.In the design process of the hydraulic system,static index of hydraulic components are single considered,this is not perfect.Becomes hydraulic control system is composed of kinds of components,including control components,implementation components,auxiliary components and so on;the effect of their combination can not be ignored,which has a great influence on the dynamic characteristics of the hydraulic system and affecting the tension control directly.In this paper,the hot rolling strip tension control hydraulic system in an iron and steel enterprise is as the research subject,and its dynamic characteristics is studied.The aim of this study is to improve the stability of hydraulic system on controlling steel strip in the production process of steel strip rolling,so that the system can be further improved in improving the precision of steel strip rolling.In addition,in the process of controlling the steel strip tension,instantaneous switch of servo valve will cause hydraulic shocking,which has a great influence on the service life of hydraulic components and the safety of system.The study of this paper will put forward the further improvement scheme,which provides reference for the design and optimization of domestic hydraulic system.The research contents are as follows:(1)the mathematical model of the servo valve,accumulator,hydraulic cylinder,pipeline and so on is established,and the main parameters of the components are analyzed.The conclusion is obtained by main parameters analysis,Proofing of the pre-charging pressure and volume of storage,the diameter,length of the pipe between hydraulic cylinder and servo valve,oil pressure,servo valve flow coefficient have great influence for hydraulic system dynamic characteristics and directly affect the stability of the hydraulic system.This chapter lays a theoretical foundation for the following simulation analysis.(2)the working principle and function of the looper device are introduced,and the simplified structure of the looper is obtained;then the force analysis of looper is carried out,and the relationship between the total load of hydraulic cylinder piston rod and the displacement of the piston rod is calculated according to the actual structure size and position value;In order to reduce the complexity of the model,the relationship between the total load of hydraulic cylinder piston rod and the displacement of the piston rod is linearized,and the fitting straight line is obtained,which lays the foundation for the following establishment of simulation model.(3)The simulation model of tension control hydraulic servo system is established by using Hy Pneu software,and the main simulation parameters of the system are calculated.Then the pre-charging pressure and volume of storage,the diameter,length and elastic modulus of the pipe between hydraulic cylinder and servo valve,oil pressure,servo valve flow coefficient,oil elastic modulus and other related parameters is simulation analysed,and some qualitative results are obtained,which provide theoretical guidance for the design and optimization of the system. |
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