| The accuracy of strip gauge and strip flatness are two quality targets of strip production. At present, they have huge advancement with the development of rolling theory, control theory, and artificial intelligence theory and with their application in the rolling process. However, It's still one of researching hotspot problems in strip gauge control accuracy.a full digital thickness closed loop control system is developed for 650mm cold strip reversing mill, and its basic construction and functional characteristics are introduced. The system's functions including closed loop monitoring control, pressure or displacement inner loop control, tilt roll adjustment, displacement inner loop with gauge outer loop, pre-control, and so on. In addition, a new control scheme which connects the pressure inner loop with the gauge outer loop is designed and applied in the AGC system of cold strip reversing mill, thus the effects of import strip thickness fluctuation and roll eccentricity on the export strip thickness are restrained. The real application results in Zhengzhou Second Steel Plant show that this control system can achieve a high precision of ± 3μm, and the maximum rolling velocity is 7.6m/s. And two indexes related to quality and quantity are better than the MINO 650 cold strip reversing mill which was imported from Italy. And remarkable economic and social benefits have been achieved.In this paper ,the model and parameters of hydraulic servo position system are set up and computed, basic theories used in the process of designing the robust controller are introduced: robustness of control system, lower LFT and output feedback H_∞ control, and so on. then output feedback H_∞ controller of hydraulic servo position system is designed .finally a respectively better controller is acquired by Matlab program, and simulation is proceeded.To the question that the gain of controlled object of gauge control outer loop slowly time-variety when the mill conditions change, Online adaptive...
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