Robust Control Of AGC System For Rolling Mill Based On Servo Compensation And LQR

The thickness accuracy is one of the most important indexes to measure the quality of the plate and strip,and one of the main objectives of improving the quality of the plate and strip.Therefore,Automatic gauge control system plays an important role in the process of plate and strip rolling.It becomes an indispensable part of the modem plate and strip production.The development of AGC system experiences from coarse to fine,from low to high development process,many advanced control theory are applied to AGC system of rolling mill where the thickness precision of the strip is improved to some extent,butthere are still many problems and shortcomings need to be solved and improved.By consulting a lot of literature,this thesis analyzes research background and the development present situation at home and abroad of the rolling mill AGC system,Aiming at the existing problems and shortcomings of rolling mill hydraulic AGC system to make improvements to the control method and the control method applies to position closed-loop control and rolling force closed-loop control of the mill hydraulic AGC system,the main work is as follows:Firstly,starting from the basic theory of the thickness control of rolling mill,summarizes the working principle of the rolled piece rolling,analysis the main causes of rolling piece thickness fluctuation,summarizes the mathernatical expression of mill hydraulic AGC system components.The nonlinear mathematical model of the hydraulic AGC system of rolling mill is established with the displacement of the valve core.The linear model of the system can be switched is obtained by the linearization processing of the mathematical model of the AGC system.And then analyzes the mode of the mill reference input signal and the disturbance input signal,the position control mode and rolling force control method of the rolling mill are studied respectively.Servo compensator is introduced to set up the augmented system model.Dynamic output feedback controller is designed.By using LMI,regional pole placement,LQR and other tools to solve the control parameters,to optimize its transient performance and achieve robust control.Finally,using MATLAB simulation to verify the controller of the dynamic performance and steady state performance and anti-interference ability.It is proved that the controller is designed with good performance,can meet the requirements of the hydraulic AGC system of strip rolling.