Control Research Of Hydraulic AGC System For Plate Mill

With the continuous development of the steel industry, the thickness is an important quality index of plate-strip, and the requirements of the thickness accuracy of the people are constantly improving. Hydraulic Automatic Gauge Control is one of the main methods of gauge control because it has the advantages of high precision, simple operation, safety and reliability, and so on. And it has been widely concerned by experts and scholars. Hydraulic AGC system combined the advantages of automatic gauge control technology and hydraulic servo technology, has made great progress than before. But hydraulic AGC system has characteristics of nonlinear and strong coupling, and the control process is influenced by many variables, so the traditional PID control cannot meet the requirements of high precision rolling. In order to improve the control precision of hydraulic AGC system, this article studies the control strategy of Hydraulic Automatic Gauge Control system.In this article, the hydraulic AGC position control system block diagram is built on the basis of analyzing the composition and control principle of hydraulic AGC system. Then use the mechanism modeling to establish mathematical model of hydraulic power components, respectively to servo amplifier, electro-hydraulic servo valve, and asymmetric cylinder. And determine the parameters of the model according to the actual process. Finally, on the basis of the mathematical model of each part, establish the mathematical model of the hydraulic AGC, and carry on the reduction then obtain the transfer function of the control system.Then aim at the shortcomings of the traditional PID controller, designing a fuzzy PID controller, can realize the adaptive setting of PID parameters, and using m language to write programs in MATLAB software then applied to hydraulic AGC position control system. The simulation results show that the fuzzy PID controller can improve the response speed and stability of the system, but when the system parameters change, its robustness is not very good. At the same time, in the process of designing fuzzy controller, need to write fuzzy rules item by item according to expert’s experience, so it has some limitations in the process of practical application. The fuzzy RBF neural network PID controller is designed for the problem of the fuzzy PID controller. The simulation results show that the proposed method can improve the speed and stability of the system and improve the robustness of the system when the system parameters change. So this method can better meet to the requirement of automatic thickness control system in modern metal rolling industry, has strong practicability.