Study On Vibration Characteristics And Control Of Rolling Mill Roll System Under Nonlinear Binding Force Of Hydraulic Cylinder

Due to the progress of science and technology and the development of human society,people's demand for life products and quality of life is getting higher and higher,and then more and more attention is paid to the vibration problems existing in rolling production process.Because of the complexity of the mechanical structure of the rolling mill,the nonlinear phenomenon of the roll system is easy to occur during the rolling process,which results in the vertical vibration of the roll system.Therefore,researchers are eager to find out the vibration mechanism characteristics of the roll system,find the source of the roll system vibration phenomenon,so as to better solve the way to eliminate the rolling mill vibration and improve the accuracy of the rolling process.In this paper,the vibration characteristics of rolling mill roll system under the constraint of nonlinear spring force and friction force of rolling mill hydraulic cylinder and the control method of vibration absorber are studied in this paper.Firstly,the limitation of the research on the nonlinear binding force of vertical vibration of the roll system is studied.According to the characteristics of the four roll mill's mechanical mechanism and the nonlinear characteristics of the rolling mill's hydraulic cylinder,the expression of the nonlinear spring force and friction force of the hydraulic cylinder is obtained.Then the dynamic law of nonlinear spring force and nonlinear friction force of the hydraulic cylinder of rolling mill are studied respectively.The above results further promote the development of the research work on vertical vibration of rolling mill roll system under the nonlinear binding force of hydraulic cylinder.Secondly,referring to the mechanical characteristics of the roller system and the nonlinear characteristics of the hydraulic cylinder,considering the nonlinear spring force and friction force of the hydraulic cylinder of the rolling mill,a vertical vibration model of the rolling mill system under the nonlinear binding force is established.The average method is used to solve the rolling mill roll system vibration system under the nonlinear constraint of the hydraulic cylinder,and the dynamic amplitude frequency responseequation of the vibration system is obtained.The effects of rolling parameters on the time domain characteristics,amplitude frequency characteristics and bifurcation characteristics of rolling mill roll system vertical vibration are analyzed by simulation.This provides a theoretical reference for the suppression of plate rolling mill vibration.Finally,based on the vertical vibration model of rolling mill roll system,a control model of vibration absorber under the constraint of nonlinear spring force and friction force of hydraulic cylinder is constructed.Based on the model,the dynamic equilibrium equation of two degrees of freedom is established,and the balance point of the coupling system of the strip mill is analyzed.Then through the method of multiple scales of the two degree of freedom equation of the amplitude frequency response equation,then the main resonance is analyzed and Simulation of internal resonance absorber added before and after the vibration of rolling mill rolls of the time domain and frequency domain characteristics and different absorber parameters on vertical vibration amplitude and frequency characteristics of roll system influence.The control model of rolling mill vibration absorber provides a theoretical reference for further suppressing vertical vibration of the hydraulic cylinder under the nonlinear constraint of the mill by means of the mechanical structure of rolling mill.