Math Model For The Modern Strip Mill And Its Application

The integrated automation system for strip production is the most representative system of complex industrial process control.The control object in strip rolling production has the complex characteristics of multi-variable, strong coupling,nonlinear, large time-delay and time variation and so on.Furthermore, in which auto-control system is especially featured with high precision and high speed, then become the most complicated and difficult integrated automation system. Which level and scale are always highlighting development phase of a national industrialization, automation, informatization to a large extent.Compared with the traditional strip rolling mills, modern ones are characterized by hydraulic driven mechanical equipment. AC speed regulation of main and auxiliary electric drive, the complete three-level computer control system and all ready testing instruments etc.,their rolling process are supposed to rely on math models. Therefore, math model is becoming the key technology in modern strip mills’control. Establishing and applying high availability and high precision mathematical model are the fundamental technology to enhance an enterprise’s competitive strength with developing and producing satisfied steel products, improving the quality of products, maintaining the stability of making process, saving energy and reducing cost.Taking strip rolling process as the object, with the perspective of theory modeling and data-driven, this paper studied the complicated mechanism models and worked modeling method out which is based on knowledge and data-driven. It made full use of the historical and real time data made by industrial processes, adopted modeling method like artificial intelligence, statistics, finite element analysis with the goal of optimizing product quality and promoting product efficiency and established the key mathematical models of strip mill to fulfill the transformation from the advantages of data resource to productivity effect and product quality.The following 4 aspects are the main research work and innovation:1) A model including roll temperature field and thermal contour was put forward combining genetic algorithm and finite element analysis. The effective technical support for shape control was provided by analysizing the influence of rolling parameters on the temperature field as well as minimizing the impact of the heat roller on the flatness.2) A multiple RBF neural network model for rolling force was established by combing with methods of wavelet multi-resolution analysis and multiple RBF neural networks, where the rolling force is decomposed and reconstructed into sub signals which correspond to different influencing factors. The simulation results show that the model can truly reflect the intrinsic mechanism of the rolling force variation, and it is an effective method for rolling force modeling with the short network training time as well as the high prediction accuracy.3) The working roller flexibility, the key parameter on setting bending force, equation was deduced and then the roller bending force model for a four-roller mill was presented by adopting the method of explicit dynamic elastic FEM (Finite Element Method). The model can simulate the strip rolling process, study and analyze the influence law of the hydraulic bending roll on the flatness parameters during the rolling process as well as the working roll parameters. The work is fundamental for further model on flatness control and optimization.4) A flatness pattern recognition model was deduced based on Legendre polynomial. The model has less computation and clear physical meaning for its polynomial coefficients directly corresponding to the three basic means to shape control. It is easier and more flexible on project implementation. The results have been successfully applied in a 1850mm aluminum foil cold rolling production line, and got good control effect.The outcome further enriches the theory and method of optimization modeling based on knowledge and data-driven on complex industrial processes and promotes industrialization by informatization and optimization operation and control on modern strip mill.