Study On Control Systems Of Rolling Mill Vertical-Torsion Coupling Vibration

With the progress of modern steel rolling process,the quality of the requirements of rolling products and more stringent.It is urgent to solve the vibration problem of strip mill.Scholars have also changed from the mechanical parameters to design controller to solve mill vibration problems.Moreover,many scholars have found that there is coupling relationship between vertical vibration and torsional vibration of rolling mill,but little research has been done on how to solve the coupling problem.Therefore,the problem will be resolved from the plate rolling mill vertical vibration,vertical coupling decoupling of these two aspects of the study.Considering the dynamic rolling force,a vertical vibration model of two degrees of freedom and four degrees of freedom is established.Based on the single-mass vertical vibration and torsional vibration system,a two-input-two-output vertical-torsion coupling model is established.Aiming at the problem of vertical vibration of rolling mill,two kinds of control methods,auto-disturbance rejection and sliding mode reverse are designed.The inner loop and outer loop auto-disturbance rejection controller are designed for the work roll and back-up roller respectively.The nonlinear observer and the external disturbance are tracked and compensated by using the ESO to overcome the dependency of the system on the model parameters.Experiments show that the controller can track the target trajectory well,has the advantages of small overshoot and fast adjustment,and can be quickly restored to stability after external disturbance,and has strong robustness.The nonlinearity and external disturbance are regarded as the integrated perturbation term,and the extended state observer is used to observe,estimate and compensate the disturbance.The dependency of the system on the model parameters is overcome.Then,a robust sliding mode backstepping controller is designed for the two-degree-of-freedom vertical vibration system,and an improved reaching law is designed to weaken the buffeting phenomenon.The simulation results show that the controller can track the target trajectory well,and can recover quickly after being disturbed.It is robust and can effectively reduce the buffeting phenomenon.A robust decoupling control strategy is proposed for vertical-torsional coupling problems.First,the feasibility of the controller parameters is proved,and then a suitable weighting matrix is ??selected for the coupled system.The experimental results show that the robust decoupling controller can eliminate the coupling between vertical vibration and torsional vibration.Compared with diagonal matrix decoupling,the robustness of robust controller is better than that of diagonal matrix decoupling controller.