【作者】 梁勋国；

【导师】 王国栋； 徐建忠；

【作者基本信息】 东北大学 ， 材料加工工程， 2009， 博士

【摘要】 本文以涟钢1720mm冷连轧机板形优化和唐钢1800mm冷连轧机工程项目为背景,对六辊冷连轧机板形控制系统进行了深入的研究,针对板形控制系统存在的不足,建立了薄带钢冷连轧板形预设定模型、板形前馈控制模型和基于最优化原理的板形闭环反馈控制模型。工业实验及现场应用结果表明,建立的模型具有良好的板形控制能力和可靠的板形控制稳定性。本文的主要工作包括：(1)对涟钢1720mm冷连轧机和唐钢1800mm冷连轧机板形控制系统进行了深入的研究分析,指出了这两套板形控制系统存在的不足。(2)分析了薄带钢轧制过程,带钢宽度以外工作辊边部接触对工作辊受力和变形的影响,采用修正的影响函数法建立了六辊轧机辊系弹性变形计算模型；利用实测轧辊温度计算了工作辊热凸度分布,与辊系弹性变形计算模型相耦合,建立了六辊轧机辊系变形整体计算模型。模型的计算结果与实测数据吻合较好,证明了该理论模型是实用可靠的。(3)建立了薄带钢冷连轧板形预设定控制模型。分析了带钢宽度、单位宽度轧制力、工作辊直径和工作辊凸度等因素对最佳中间辊横移位置的影响,建立了中间辊横移位置预设定模型；分析了带钢宽度、单位宽度轧制力、中间辊横移位置、带钢入口厚度、带钢凸度、轧辊直径和轧辊凸度等因素对最佳弯辊力的影响,建立了弯辊力预设定模型。(4)分析了各种因素对整体补偿板形前馈控制模型补偿系数的影响规律,建立了考虑带钢宽度、中间辊横移位置、轧辊直径和轧辊凸度等因素的补偿系数表格,计算了相应轧制工况下的补偿系数,在实际应用中,根据中间辊横移位置进行线性插值求解。(5)建立了采用工作辊弯辊和中间辊弯辊相配合以补偿轧制力变化的最优综合补偿板形前馈控制模型。将实测轧制力变化量转换成带钢宽度方向上轧制压力变化量的分布,根据工作辊弯辊和中间辊弯辊对有载辊缝压力分布的调控效果不同,采用了最优综合控制算法,从而得到了最优的弯辊力前馈修正量。(6)建立了基于多变量最优化的板形反馈控制模型和基于二分法的乳化液分段冷却控制模型。将板形误差转换为有载辊缝内压力分布的变化量,充分考虑了各板形调控机构的板形控制能力和相互之间的耦合关系,采用Frank-Wolfe最优化算法求解板形控制目标函数,从而获得了板形调控机构允许控制范围内的最优反馈修正量；基于二分排序法的乳化液分段冷却控制模型,对残余板形误差使用二分法进行降序排列,根据设定的喷嘴开启比例确定每个冷却喷嘴的控制状态。(7)进行了工业实验研究,对本文建立的模型板形控制效果进行了验证和分析。工业实验及现场应用结果表明,本文建立的控制模型克服了原模型的不足,提高了板形预设定精度,强化了板形前馈控制作用,改善了板形反馈控制效果,从而获得了良好的带钢板形质量。本文的研究内容,针对具体冷连轧机的板形控制模型进行了优化和改进,具有很强的实用性,对于六辊冷连轧机板形控制系统的开发也具有理论指导意义和实际应用价值。更多还原

【Abstract】 This paper was based on the strip shape optimization project of 1720mm tandem cold rolling mill(TCM) in Lianyuan Iron & Steel Corporation and the 1800mm TCM project of Tangshan Iron & Steel Corporation(TISCO). Flatness control systems of six high TCM have been thoroughly studied. Aiming at the defects of the two flatness control systems, shape preset model of thin strip cold rolling, flatness feedforward control model and flatness feedback control model which base on optimization theory have been built. Good flatness control ability and reliable control stability of these models were proven by industry experiments and online application. The main works are shown as follows:(1) Flatness control systems of 1720mm TCM in Lianyuan Iron & Steel Corporation and 1800mm TCM in TISCO have been studied and analyzed. Defects of the two flatness control systems were pointed out.(2) Rolls elastic deformation model of six high mill was developed by using modified influence function method. In this model, the effects of work roll edge contact out of the strip width on work roll’s load distribution and deformation have been considered in rolling thin strip. Work roll thermal camber has been calculated based on the measured temperature of roll’s surface. The total rolls deformation model of six high mill was developed by combining rolls elastic deformation model and work roll thermal camber model. The results of calculated data were in good agreement with the measured value. This verified that the theory model is reliable.(3) Flatness control preset model of thin strip was put forward. The relationship between optimum intermediate roll position and strip width, specific rolling force, work roll diameter and work roll crown has been discussed, and the intermediate roll position preset model was set up. The effects of strip width, specific rolling force, intermediate roll position, entry strip thickness, strip crown, roll diameter and roll crown on optimum bending force have been analyzed, and the bending force preset model was built up. (4) Effects of main factors on the gains in global flatness feedforward control model were discussed. Multidimensional lookup table that considered strip width, intermediate roll position, roll diameter and roll crown was created after many gain values of difference rolling conditions have been calculated. In practical application, linear interpolation method was employed to give the gain values.(5) An optimum flatness feedforward control model was put forward which intergrated work roll bender and intermediate roll bender to eliminate roll load disturbances. The roll load disturbance was transformed to the transverse specific force distribution, different regulate effects on specific force distribution in roll gap of work roll beneder and intermediate roll bender have been considered, and optimum corrections of the bending actuators were calculated by using a global approach.(6) A flatness feedback control model base on multivariable optimization theory and an emulsion multizone roll cooling model which using dichotomy method were built up. Flatness error was transformed to the variation of specific force distribution in roll gap, The flatness control cost function was solved by Frank-Wolfe algorithm and then the optimum corrections in flatness control actuators’regulatory range could be got. In this model, the flatness control abilities and effects among the flatness control actuators have been taken into account. In the emulsion multizone roll cooling control model, the cooling sprays control state decided by the sprays open ratio after the residual flatness error has been sorted in descending order by employing dichotomy method.(7) Industry experiments were carried out to validate and analyse the flatness control results of these models that have been built up in this paper. The industry experiments and practical application results showed that the precision of shape preset control was enhanced, the flatness control effects of feedforward control and feedback control were improved, and good strip shape was obtained by applying these models.The present paper was focused on the optimization of flatness control models for six high TCM. It can provide great help in theory and practical application to the development of flatness control system of six high TCM.更多还原