Research On Rolling Force Model And Elongation Control System For Cold Strip Skin Pass Mill

Temper is the final critical process in ensuring the finished quality of cold rolling strip. It is very important to ensure the interior structure property of strip and meet the user's requirement. This thesis is based on the technology assimilation project on a single stand skin pass mill which is being used in a cold-rolled stainless steel production line. A lot of research has been done on the rolling force model and the elongation control system through a lot of field research, data collection and simulation.Firstly, introduce the composition of the skin pass mill from the mechanical and electrical sections briefly. Meanwhile, analyze the primary elongation control theory and the three main control methods. Then, the thesis focuses on the study of the automatic control system in which the elongation is controlled by adjusting the rolling force.And then, some problems effecting on accuracy of the elongation control system are present. According to these problems, the mainly studies in this thesis are given as follow:(1) Found an integrated model of temper rolling force. The accuracy of the rolling force calculation will directly affect the accuracy of the elongation control precision. According to the rolling theory and research on the factors that influence the rolling force, the traditional mathematical model of rolling force and the Bland-Ford-Hill model which is suitable for engineering calculation are derived in detail. To get higher accuracy, use the exponential smoothing algorithm to achieve the model adaptive correction. Then an integrated temper rolling force model is obtained by combining the traditional model and RBF neural networks model. After studying, training and simulation of the model using practical production data, the results indicates that integrated model of temper rolling force has higher accuracy compared with the traditional mathematical model.(2) Design of optimized elongation control system based on DMC. According to the characteristics of cold rolling temper mill, use the Dynamic Matrix Control algorithm to optimize the elongation control system, and then design an optimized elongation control system based on DMC. Simulation is made to compare the two systems from their tracking performance and anti-jamming performance through Simulink. The result shows that the DMC-based elongation control system has more favorable dynamic characteristics and higher tracking and anti-jamming performance.