High performance motor-pressing control system of Hot Plate Leveler based on model Predictive Control
This paper introduced the configuration of Hot Plate Level system, and built the mathematic model of pressing device which is driven by two asynchronous motors. As we known from the model, the pressing system was a classic low gain, non-linear and high-coupling system. Rising the speed gain of asynchronous motor system, expanding the band width of close-loop speed system and increasing speed response of pressing system were the core methods of reducing the disturbance of speed close-loop system. The keys of controlling close-loop position system were eliminating the non-linearity of speed-loop and hysteretic position-circle which is caused by the backlash of worm wheel and gear. The structure of the pressing system based on two motors, by which the rudimental plastic deformation can be removed, produced the high-coupling characteristic, which reduced the position precision and dynamic performance. By simplifying pressing system according to the system mechanical structure and using the controller based on Predictive Control Theory, the four pressing position of the pressing system is adjusted and balanced, and the linearity and decoupling were realized. The complex controlling system for motor-pressing hot plate leveler was successfully used in Tang Shan Heavy Plate Mill Line 2, which increased the production capability of the rolling line. Further study and solution is made to overcome the choke point of the precise positioning in most Plate Level machine. It is proved via matlab simulations that high performance and strong robusticity can be achieved.