Research And Simulation Of Hydraulic Looper Control System In Hot Rolling Mill

With the development of modern industry technology, the requirement of steel quality,grade and production is higher and higher. The finish rolling of hot rolling is the most important part, and during the finish rolling, looper control is the key technology which determines the quality of strip. Currently, both at home and abroad, the study on looper control is active in development.Based on the background of a 1580 hot rolling production line, it takes the hydraulic looper control system of the finish rolling as the study project in this paper. As the looper control system is coupling, multi-variable and nonlinear, it established the mathematical model of the strip tension system, the looper height system, the hydraulic system of looper,then it set up the looper tension system. Aiming at the created mathematical model, it conducted the research and simulation of traditional control method by MATLAB/simulink, and the results showed its wonderful decoupling control, but in the disturbance fluctuation, it also responded slowly and presented a bad anti-jamming capability, and its response accuracy is poor when the parameters changed.In the traditional control method, it takes the looper system as a dependent system ignoring the interaction with other systems such as gauge system、temperature system, so it could not coordinate the coupling effects between systems. The automatic gauge system is the main factor causing the disturbance of looper system, therefore the independent looper system did not avoid the strip fluctuation radically. In view of the problems above,it established the gauge-looper system which contains strip tension control、looper height control and gauge control. A fuzzy controller is designed for the gauge-looper system due to the advantage that fuzzy control strategy is robust and is strong fault-tolerance.According to the results of the analysis and the simulation, this method can effectively eliminate the interaction between the looper system and the gauge system compared with the traditional method. It can restore stability quickly when disturbed. It shows good performance in robustness and stability.