Active Vibration Suppression Based On Hot Rolling Mill Coupling Vibration

Rolling mill vibration not only exists generally in the iron and steel production enterprises,but also limits the production capacity of rolling mill and becomes an obstacle to the production of thin and high value-added products.It is an urgent technical problem to be solved in the rolling field at home and abroad.Rolling strip is conducted through the mutual interaction between the mechanical system,hydraulic system,electrical system and strip.Any subsystem parameters change will have an effect on rolling mill vibration.So it is very significant to study the dynamic characteristic of mechanical-electrical-hydraulic coupling vibration through the effective mathematical model.It is well known that there are many factors influencing rolling mill vibration.However,the vibration suppression methods of tuning rolling mill parameters which are currently used in field are only effective for a certain kind of vibration.Therefore,it is of great significance to explore common active vibration suppression measures.Based on the mechanical-electrical-hydraulic coupling vibration and the control method the active vibration suppression method of the hot continuous rolling mill is proposed.The following research is carried out in this paper:For F2 and F3 of a 1580 hot continuous rolling mill,the online remote monitoring system is used to monitor the coupling vibration of entire rolling line.Vibration speed sensors are used to obtain the vibration information of rack,torque telemetry system is used to capture the torque vibration of main transmission system and the electrical,hydraulic and rolling process informations are obtained through ODG system.The mechanical-electrical-hydraulic coupling vibration characteristic is obtained.Based on the Sims rolling force model,a vertical vibration coupling model including rolling process,mechanical structure,hydraulic servo system and control system is established for numerical simulation.The validity of rolling force model,system dynamic response and coupling vibration model are verified by comparing with the data collected from 1580 hot continuous rolling mill.Through numerical simulation,the influence of the steaty state part of deformation resistance,rolling speed,piston side area of hydraulic cylinder and equivalent stiffness,as well as the dynamic part of entry thickness and deformation resistance on rolling mill vibration is analyzed,The analysis result shows that reducing the deformation resistance,rolling speed and equivalent stiffness,and increasing piston side area of hydraulic cylinder can decrease rolling mill vibration power;the dynamic part of deformation resistance and entry thickness can stimulate the harmonic-frequency vibration.Based on the dominant pole theory,the generalized frequency method and the amplitude-phase margin theory,a parameter tuning method which can guarantee both the desired closed-loop dynamic response and the closed-loop system stability is proposed for the single-degree-of-freedom PID controller.Based on the desired dynamic method and the generalized frequency method,a parameter tuning method(DDE-GFM)which can guarantee both the desired closed-loop dynamic response and the closed-loop system stability is proposed for the two-degree-of-freedom PID controller.DDE-GFM method is compared with the Panagopoulos method.The result shows that DDE-GFM method possesses smaller overshoot and shorter settling time when the two methods have the same stability margin.Based on the bandwidth method and the generalized frequency method,a parameter tuning method(BD-GFM)which can guarantee both the desired closed-loop dynamic response and the closed-loop system stability is proposed for linear active disturbance rejection controller(LADRC).Compared with PID,BD-GFM method possesses smaller overshoot and shorter settling time when these two methods have the same stability margin.Based on extended state observer(ESO),three active vibration suppression methods,high-order ESO compensation,low-order ESO with single channel compensation and low-order ESO with double channel compensation,are proposed for the vertical vibration of hot rolling mill.The simulation results show that the closer the setting vibration frequency of high-order ESO compensation is to the actual vibration frequency,the better the vibration suppression will be;the low-order ESO with single channel compensation which absorbs the work roll vibration to the backup roll vibration is similar to the dynamic vibration absorber;the low-order ESO with double channel compensation can reduce the work roll vibration and the backup roll vibration at the same time;three vibration suppression methods possess excellent robustness.Finally,the validity of high-order ESO compensation is verified by experiment.