Strip Mill Pressure System Automatic Control Research

With the rapid development of science，our national economy has achievedrapid development, and the society calls increasing demands for the quality ofthe steel. As the thickness is one of the most important qualitative indicators,AGC (Automatic Gauge Control) plays an indispensable and important role inthe modern plate production，because its control performance will directlyaffect the quality of the product. With the roll speed and the automationtechnology developing, to control the strip’s thickness deviation and improveits quality, the hydraulic AGC method is now extensively used in the world.Because the hydraulic AGC can adjust the roller’s equivalent stiffnessaccording to work conditions, with quick response, can get high precisioncontrol result.This thesis is based on the national key project “the transformation ofNanJing MeiQing Technology Co., Ltd. composite production line”, havingstudied the refined composite roller in the line, the thesis proposed thetransformation of the rolling mill’s AGC. The main contents are as follows:Firstly, the thesis has researched the theory about the roller’s work process,analyzed the various factors affecting the rolling thickness accuracy anddescribed the roller’s AGC system. To improve the AGC’s control accuracy, weplan to change the AGC system into the combination of the EAPC and HAPC.The EAPC system is responsible for the coarse-tuning and the HAPC system is in charge of the fine-tuning. Secondly, this thesis established the dynamichydraulic AGC positional servo control system model and apply the Fuzzy PIDcontrol in the hydraulic AGC system.Finally, as the AMESIM software has the physical structure of themechanical and hydraulic elements, this thesis established the hydraulic AGCposition control system’s mechanical and hydraulic simulation model with thebasic elements modeling method using the AMESIM and designed the fuzzyPID controller using the powerful data processing software MATLAB. And takethe advantage of the AMESIM/Simulink interface to complete the servoposition control system co-simulation. The results of the co-simulation showthat the proposed control scheme has certain advantage, compared with theconventional PID, the fuzzy PID controller can get better performance, and theresearch in the thesis provides a way to improve the precision of rollingthickness.