Advanced Control Theory And Application In Rolling Process

The rolling process is one of the key processes in the metallurgical production,and the quality shape and thickness of the strip is the most concerned issue.In view of the implementation of control system,there existdifficulties,such as strong coupling,nonlinear and disturbance.Therefore,it is difficult to obtain a unified deterministic linear model and a classical theory which are satisfied with the requirement of the current high-precision and high-speed control.In this paper,some advanced control approaches are proposed.Moreover,the application level of control theory in the rolling process is improved.The organization and contributations of this dissertation are as follows.Firstly,the design of a robust decoupling controller for a multivariate control system with parameter uncertainties for the hot rolling mill process is proposed.The necessary and sufficient conditions for robust decoupling controller are also proposed.Then,a modified multivariate model is developed by analyzing the changes in the dynamic response resulting from perturbations in the tension and angle system parameters in the hot strip rolling process.Furthermore,the selection method for a practical weighting function is studied,so that the robust and decoupling performance can be simultaneously realized for the controller implementation.Finally,the effectiveness of the proposed control approach is demonstrated using a case study from an industrial hot rolling mill.Secondly,a pole placement method for multivariable decoupling control is proposed.This aims to achieve robustness between the strong coupling effect of convexity and thickness and the uncertainty of system model parameters.To realize robust and decoupling control at the same time.Theoretically,the sufficiency of decoupling simultaneous robust controller design is proved by the pole placement of non-singular diagonal matrix and matrix polynomial decomposition theory.The performance of proposed control algorithm is demonstrated by a case study on the convexity and thickness control system in rolling processes.Thirdly,a method for selecting analytical calculations of weighted function matrices is proposed.It is proved that the weighting matrix can be calculated and selected to achieve the guarantee of interference decoupling and robustness,which has an important impetus for the industrial application of robust decoupling controllers.Finally,a control system design method based on extended state observer SMVS(sliding mode variable structure)is proposed for the problem of tension control accuracy of AC motor in coiler rolling process.In order to deal with the nonlinear problem,improve the control performance,the feedback linearization theory is applied to solve the system model.A detailed description of the modeling methods,theoretical analysis,and simulated experiments of all the studies is given.