Modeling And Simulation Of Hydraulic AGC System For Tandem Cold Rolling Mill

With the rapid development of modern industry, the demand quantity of cold rolled strip is increasing. At the same time, the rolling method and rolling technology are developing rapidly. The hydraulic pressure control system is characterized by its fast response speed, and is widely used in the rolling control system. This paper relies on Shandong Guanzhou Group 1450 mm five stands tandem cold mill projects AGC(automatic gauge control) system and hydraulic AGC system as the research object, regarding 1st stand of hydraulic AGC system as the research object. After studying domestic and foreign relevant literature, model the tandem cold rolling mill hydraulic AGC system and do the simulation experiment based on theoretical analysis and field research.First of all, study the field production process and its automatic controlling system composition, which include the basic automation(Level 1), process automation(Level 2) and HMI interface. At the same time, the correlation thickness control theory and the mathematical model of various thickness control modes should be understood in order to prepare the establishment of the rolling model.Secondly, the open-loop transfer function of hydraulic AGC system is deduced by using the basic equation of hydraulic servo system. Then get the transfer function by analyzing each component used in the project. Do the system simulation with step signal of the unit as input signal. Study the time domain and frequency domain characteristics of the system, and analysis the result of the simulation. According to the problem of the system, the PID controller is added to the system, and the control system is optimized. Due to the PI parameters of traditional PID controller can not be verified according to the change of system parameters, meanwhile, hydraulic servo control system is required for the fast response speed. So it is proposed with fuzzy control theory to make the system improved. The simulation of the improved system is carried out with the MATLAB simulation software, and it is proved that the system has a better controlling effect on the response speed, anti-interference ability and on-line real-time adjustment of PI parameters.Finally, by using mathematical model, field data and cold rolling dynamic model of 1st stand hydraulic AGC system, I complete the simulation with MATLAB/Simulink software. The simulation results are consistent with the rolling theory. Analysis the exit thickness difference curve of conventional PID control and fuzzy PID control, and make a Comparison with the two control strategy. In addition, the accuracy of the rolling model and the accuracy of the simulation method are verified by comparing the simulation curves with the field measured curves.