Control And Optimization Of Shape Set Model On Hot Strip Mill

Shape precision is not only an important quality index in hot strip rolling,but also decides market competitiveness of product.In the actual rolling process,the strip plate shape is affected by many factors,such as inlet convex,front and rear tension,rolling force,bending roll force,rolling speed and so on,which has strong nonlinearity and the shape control effect does not reach the ideal effect.Shape set control system is a very important part of the whole shape automatic control system,which determines the control precision of strip head plate shape.At present,the shape control technology has become one of the core technologies of hot strip rolling production,and it is also the frontier and hotspot of rolling technology research and development.In this paper,the basic theory of shape control and the shape set model of PC Mill are analyzed in depth,with the aim of improving the quality of hot rolled plate,the main research contents and achievements are as follows:1.Based on convex calculation model,the roll thermal convex model,through is created and the comparison between the roll system thermal convex theoretical analysis data and the measured roll system thermal convex data is analysed.The use of linear regression method is to analyze the heat parameters of the roll system,so that the mathematical model calculated in the roll thermal convex results and the actual thermal convex gap is the smallest.Finally,the purpose of thermal convex model optimization is achieved.2.Based on the exponential smoothing method,the convex self-learning function and straightness self-learning function are improved,and the bending roller force is continuously optimized in the shape set model,so as to achieving the goal of optimizing the bending roller force model,so that the convex and straightness of the plate shape can be more effective optimization control.3.Due to the time-varying and nonlinear factors in rolling process,the nonlinear PID control technology is introduced into the feedback shape control technology.Based on nonlinear PID,considering the change of the control amount ±(10-15)% which is given on the basis of the setting of the conventional PID control parameters,to determine the value of proportion,integral and differential.And then the corresponding change rate is determined,therefore,this control algorithm improves the anti-jamming ability of the system and obtains good control effect.4.Combining advanced shape control technology with model self-learning control technology,it not only ensures that the required convex and good straightness are obtained in the total length of strip,but also improves the control precision of the plate shape.Appling the comprehensive control theory technology to the 1780 production line,and comparing the input plate shape setting control with the non-input,founding that the hit rate of strip head convex and straightness can be found after the input plate shape setting control,the hit rate of strip head convex and straightness can be increased by 7% and 5% respectively.