Research On Adaptive Gauge Control Algorithm For Four Rolling Finishing Mill And Software Development

Automatic gauge control (AGC) system play a key role in guarantying the quality of hotrolling steel products. Up to now there is still a large gap of domestic plate thickness accuracycompared to foreign countries’ technique, as well as the yield of the products. In order to obtainproducts with higher accuracy of thickness and to improve the yield of products, we need tostudy high-precision automatic gauge control technique.Based on the process and equipment of hot rolling strip production, as well as the rollingtheory, the basic method of thickness control in plate and strip rolling is discussed, besides amass-flow gauge control scheme with width compensation is presented. Then the mass-flowclosed-loop adaptive thickness control system is designed, based on mass-flow thickness controlalgorithm and the feedback AGC control model.The mechanism model of hydraulic APC system is established based on actual project data,and the simplified APC model was acquired by simulating the engineering tuning. Then thespread theory in the rolling process is studied, and the mass-flow predictor with widthcompensation is designed combined with Z.Wusatowski spread formula. After this, theparameters of mass-flow controller are obtained according to the parameters of simplifiedhydraulic APC system model and the characteristic of mass-flow AGC. In order to overcome theprediction error of mass-flow predictor, the thickness feedback AGC outer loop is designed,based on mass-flow inner loop. Then the adaptive integral controller is also designed toovercome the delay of feedback AGC loop. The relational expression between the best integraltime constant and rolling speed is obtained in the simulation environment, so as to provide theparameters design considerations to realize adaptive thickness control model. Afterwards, themass-flow closed-loop adaptive thickness control system model, based on mass-flow inner loopand adaptive thickness monitoring outer loop, is established in the Simulink environment. Theauthor also makes a comparative analysis of the performance of control system. According to thesimulation results, the paper draw the conclusion that the mass flow thickness control methodcan be used in hot rolling, and the performance would be much better than traditional thicknesscontrol methods. At last, the CFC function blocks are established to implement the function ofcontrol algorithm in TDC platform.