【作者】 赵旭亮；

【导师】 张殿华； 徐建忠；

【作者基本信息】 东北大学 ， 材料加工工程， 2009， 博士

【摘要】 本文以本钢热轧厂的“提高1700mm热轧带钢板形控制精度的研究”项目、唐山港陆的“港陆1250mm板形控制系统开发”项目以及首钢迁钢的“迁钢2160mm热轧控制系统的消化吸收”项目为背景,系统研究了板形控制系统的理论、数学模型、控制策略以及辊型曲线优化设计。主要研究内容如下：(1)研究了板形控制理论中的辊系变形理论。采用影响函数法建立了辊系弹性变形数学模型,完善了辊间压扁和工作辊压扁的影响函数,编制了辊系弹性变形解析软件。在考虑轧辊磨损主要影响因素的前提下,建立了轧辊磨损预报模型,编制了轧辊磨损预报软件。建立了轧辊热膨胀计算的二维有限差分数学模型,采用热平衡法处理了边界条件,编制了轧辊热凸度预报软件。(2)建立了物理意义清晰的板形控制数学模型。采用空载辊缝凸度模型将影响辊缝的辊型因素综合为工作辊间辊缝凸度和支撑辊与工作辊间辊缝凸度,简化了板形控制模型结构；建立了描述单位宽轧制力、弯辊力、带钢宽度、轧辊弹性模量、轧辊直径以及空载辊缝凸度等影响因素和辊系弹性变形之间关系的均载辊缝凸度模型,给出了模型系数的确定方法；基于体积不变条件推导了考虑横向流动和二次变形影响的带钢板形预报模型；建立了考虑机架间张力和来料潜在板形不良影响的板形判别模型。(3)研究了板形控制系统的控制策略。指出传统凸度分配策略忽略了潜在板形不良的影响,且下游机架未参与凸度控制降低了轧机板凸度的命中率。提出了一种新型的板形控制策略,该策略在保证带钢板形良好的前提下,提高了目标板凸度的命中率,有利于最大程度发挥轧机的板形控制能力。建立了各板形控制手段设定计算的数学模型。根据工作辊横移位置与工作辊间辊缝凸度的关系,建立了一种确定工作辊横移位置的迭代计算方法。(4)开发了适用于常规轧机、CVC轧机和PC轧机的在线板形控制系统。为消除传统平直度反馈控制中存在的时间滞后和速度波动的影响,将Smith预估控制方法引入到平直度反馈控制中,选取调节器为积分形式,且采用带钢样本长度跟踪作为事件触发中断进行反馈控制。(5)研究了热带轧机CVC-plus工作辊和支撑辊辊型曲线的优化设计方法。根据CVC-plus辊型曲线的特点,以轴向力最小为目标函数,推导了其辊型曲线的设计方法,编制了CVC-plus工作辊辊型曲线优化设计软件。研究了支撑辊辊型曲线及轧辊热磨损对辊间压力分布和带钢出口凸度的影响。在对带钢凸度在机架间进行合理分配的前提下,建立了以辊间压力均匀化和保证机架间板形良好为目标的支撑辊辊型曲线优化设计算法。本文的研究内容面向热轧带钢在线控制,改进了平直度反馈控制系统,建立了包括物理意义清晰数学模型和新型控制策略的板形控制系统,提出了CVC-plus工作辊和支撑辊辊型曲线优化设计方法,具有很高的实际应用价值。支撑辊辊型曲线优化设计和板形控制系统已应用于唐山港陆1250mm热带轧机：辊型曲线优化后,支撑辊的轧制重量得到了提高；板形控制系统投入后,轧辊磨损和热凸度预报精度较高,板形质量有了较大的提高。更多还原

【Abstract】 Based on the project of "Research on Improving Shape Control Accuracy of 1700mm Hot Rolling Mill" in Ben Steel Hot Rolling Plant, the project of "Development of Strip Shape Control System for Ganglu 1250mm Hot Rolling Mill" and the project of "Digestion and Absorption of Control System for Shougang 2160mm Hot Rolling Mill", the theory, mathematical model, control strategy of the strip shape control system and the roll contour optimization were researched systematically in the paper. The main works are shown as follows:(1) The roll deformation theory of the shape control was studied. The mathematical model of roll elastic deformation was set up by the influence function method, the influence functions of work roll flattening and flattening between rolls were improved, and the analytical software on roll elastic deformation was developed. The roll wear model was established by taking into account the main influential factors, and the forecast program of roll wear was complied. The roll thermal expansion model was set up by the two-dimensional finite-difference method, the boundary condition was handled by the heat balance method, and the forecast software of roll thermal crown was complied.(2) The shape control mathematical model of specific physical meaning was set up. Roll contour factors which impacting the roll gap were summarized into two parameters through the unload roll gap crown model to simplify the shape control model structure. The uniform load gap crown was influenced by rolling force, roll bending force, strip width, elastic modulus of the roll, roll diameter and unload roll gap crown. The uniform load distribution roll gap model was developed to describe the relationship between the roll elastic deformation and the influencing factors. The method was provided for determining the uniform load distribution roll gap model coefficient. Based on the volume conservation, the strip shape forecast model was deduced by considering the material transverse flow and secondary deformation between mills. The shape discriminant model was set up by considering the effect of the potential shape defect and the tension. (3) The control strategy of the shape control system was researched. Due to ignoring of the potential shape defect and the absence of strip crown control by the downstream stands, the traditional crown strategy had reduced the hit rate of the strip crown. A new kind of shape control strategy was proposed to enhance the hit rate of the target strip crown under the condition of guaranteeing the strip flatness quality. The new strategy can increase the shape control capability to utmost extent. The setup calculation mathematical model of each shape control actuator was established. According to the relationship between the shifting position of the work roll and the roll gap crown, the iterative calculation method was established to determine the shifting position of the work roll.(4) The on-line shape control system was developed. Smith prediction control method, whose regulator employs the integral form, was introduced to the flatness feedback control in order to eliminate the influence of time lag and velocity fluctuation in traditional flatness feedback control; the sample length tracking of the strip was acted as the event-triggered interruption in the feedback control.(5) The optimum design methods of the CVC-plus work roll shape curve and the backup roll contour were studied. Taking the minimum of the axial force as the objective function, the design method of the CVC-plus roll shape curve was deduced, and the optimum design software was developed. The effect of the backup roll contour and the roll thermal wear on the load distribution between rolls and the exit strip crown was studied. Taking the uniform load distribution between the rolls and the fine shape between the stands as the target, the optimum design method of the backup roll contour was developed by distributing the strip crown reasonably in every stand.The main research content of the paper, which was of great practical application value, was focused on the online control of hot strip mill. The flatness feedback control system was improved; the shape control system, which contained the mathematical model of specific physical meaning and the new kind of control strategy, was established; and the optimum design methods of the CVC-plus shape curve and the backup roll contour were introduced. The backup roll contour optimum design method and the shape control system have been employed in Tangshan Ganglu 1250mm hot strip mill. The application results show that the rolling weight was increased, and the shape quality was enhanced.更多还原