Simulation & Research For The Control Algorithm Of Monitor AGC System In Eight Roller Mill

The function of the AGC system is to get the well-proportioned lengthways thickness of steel strip. Recently the AGC system has become the indispensable control system in the modern steel strip production. Therefore, it is necessary and importent to research AGC of rolling mill deeply and to apply intelligent control algorithms to it. This article relies on the subject of 1450 mm eight roller five stands continuous tandem cold mill, and the AGC systems of mill are studied.Firstly, based on the curve of mill elastic deformation and the curve of strip plastic deformation, the influence of various interference factors on the strip exit gauge is analyzed. The modes of the fundamental AGC systems are summarized. Based on 1450 mm eight roller five stands continuous tandem cold mill, which is a tandem cold strip production line researched by Chinese engineers. The equipments and the new specialties and the mathematical relationship between rack and roller gap are introduced , then applications of various automatic gauge control strategies are introduced.Afterward, because of the shortages of normal PID control method ,which is badness of parameter adjusting and poor performance, the structure and algorithm of BP-PID control are studied, which can efficiently overcome the limitations of normal PID.Finally, the monitor AGC system in 1450 mm eight roller mill was obtained, and its inner loop is the hydraulic APC system which is the core and perform institution of the monitor AGC and outer loop is the thickness gage monitor. The model of the equation between the thickness deviations and the gap deviations was set up through the least-square method which is in virtue of the software of MATLAB. Smith predictor can improve the condition of monitor AGC system, which also can solve the time-delay problem in monitor AGC system. Therefore, this paper designed a BP-PID & Smith predictor control strategies to control monitor AGC. The simulation resu1ts show good characteristic of BP-PID-Smith control method which has high robustness and fast response ability and the practicality of this method is quite good.