Coordinated Control And Experimental Research For The Speed And Tension System Of 1422 Reversible Cold Strip Rolling Mill

This research is on the background of the reform project of hydraulic AGC and electric drive system in the Zhangjiagang 1422 reversible cold strip rolling mill, and is dedicated to the whole physical modeling, the analysis and controller design and partial experimental study for the speed and tension control system of the project.Recently, a new trend of rolling technology is fully continuous rolling, high-speed and high-precision, with more high-powered speed and tension control system to deliver the cold strip. However, due to the speed and tension system in reversible cold strip rolling mill is complex and coupled systems, which can be affected by uncertainties and disturbances, it is necessary to propose robust control and decentralized control for the speed and tension system in order to weaken the coupling between speed and tension and improve its robustness. These researches have become hot spots of steel rolling industry.Firstly, a nonlinear, multivariable and coupled mathematical model, describing the dynamic of the speed and tension system in reversible cold strip rolling mill, is established from tension model, DC motor model, front-back skidding model and the systematical structure.Then, based on the given mathematical model, indirect tension control strategy and tension controller are designed for the speed and tension system in the 1422 reversible cold rolling mill, respectively.Additionally, considering the uncertainties and disturbance of the system mentioned above, a robust controller is designed using mixed-sensitivity design method, improving the robustness and disturbance rejection of the system. Meanwhile, in view of the coupling between speed and tension, from the systematical structures, a decentralized linear quadratic optimal (LQ) controller is designed by applying inclusion principle, based on decentralized control method and optimal control method. The designed controller weakens the coupling and achieves perfect static error cancellation.Finally, combining with the reform project of hydraulic AGC and electric drive system in the Zhangjiagang 1422 reversible cold strip rolling mill, partial experimental research is given. Based on existed hardware and communication network, the overall debugging and parameter optimization is executed for both the speed control of mill and indirect tension control of coils. Experimental results show that the reformed speed and tension control system satisfies the requirement of production.