Research On Looper And Shape Control Model Of Hot Tandem Rolling Based On ILQ

This paper takes the 1580 mm hot tandem rolling production line of a factory as the research object,based on the inverse linear quadratic(ILQ)theory,aiming at the looper and shape control system of hot tandem rolling,aiming at improving the quality of hot tandem rolling products as the starting point.Research in depth.A looper height and tension control model based on LQR,a looper height and tension control model based on ILQ and a coordinate control of strip thicknesscrown-tension based on ILQ in tandem hot rolling mill are proposed.The simulation and experimental results both show that the proposed control model has better control effect,and important theoretical guiding significance and practical application value for improving the performance of the hot continuous rolling looper and the shape control system and the product quality of continuous rolling.The main research contents of this paper are as follows:(1)The LQR theory and the design flow of its controller are introduced.A looper height and tension control model based on LQR is proposed.And compared with the traditional PI controller to test its anti-interference performance and response performance.The simulation results show that the overshoot of the tension and looper angle of the LQR controller is smaller than that of the PI controller,and the LQR control performance is better.(2)The ILQ control theory is introduced by analyzing the shortcomings of the LQR theory,such as the need for a lot of trial and error when selecting the weighting matrix,which makes the controller design workload heavy,not easy to adjust,and has a small scope of application.A looper height and tension control model based on ILQ is proposed,the controller parameters are tested by MATLAB,and the influence of each parameter on the performance of the controller is studied.Then,the response performance of the proposed ILQ controller is tested by comparing it with the LQR controller.Simulation results show that the proposed ILQ controller has better response performance.Finally,the proposed controller parameters are input into the PLC program and the steel rolling experiment is carried out.The actual rolling results show that the proposed ILQ controller has better control performance.It has a certain reference significance for improving the stability of the looper control system in hot tandem rolling and reducing the scrapping of strips caused by the jitter of the looper.(3)In order to further improve the control accuracy of thickness,crown and tension of hot strip finishing mill,a multi-variable optimization strategy based on ILQ control theory is proposed.Through the analysis and calculation of the field data,combined with the mechanism model and empirical formula of the rolling process,the state space model of the integrated control system for thickness,crown and tension is obtained,and a new ILQ controller is designed based on the ILQ theory and pole configuration combined with the state space model..The new ILQ controller is used to coordinately control the thickness,crown and tension of the strip.The control is simple and effective,and does not require a lot of trial and error.The control performance of the proposed ILQ controller is compared with that of the PI controller.The results show that the proposed ILQ control strategy has high control accuracy no matter when the thickness,crown and tension step signals are set separately or when the three step signals are set simultaneously.