环件径-轴双向轧制数值模拟及其多轧辊的联合控制

环件轧制过程是热力耦合作用下高度非线性、非稳态的热成形工艺,其工艺参数多,轧辊控制复杂,难变形材料的环件轧制技术还缺乏高效、便捷的数值研究手段。以轧制曲线为基本变量,建立了各轧辊之间的运动学和动力学关系,随后基于FORGE有限元软件平台,依据Φ3000 mm数控环轧机建立了环件轧制的有限元模型。模型采用力及力矩控制抱辊,通过多轧辊联合控制,能够成功实现对偏心、椭圆等弱刚度现象的预测。通过Inconel718合金全尺寸环件轧制实验,验证了所建有限元模型的可靠性。该模型预测结果的相对误差小于3%,并在机匣等典型薄壁件的研制中得到了工程化应用。

多分辨小波控制器在轧辊偏心控制中的应用

提出了一种用于轧辊偏心控制的多分辨小波控制器，它利用小波对轧制力信号进行多分辨分解．机架的轧制力中包含着许多潜在因素的累积影响，比如压下环节的动特性、轧辊偏心、测量噪声、外部干扰等，这些影响体现在不同的尺度上．通过小波的多分辨分解，这些不同尺度上的信息被区分开来，然后在控制中对轧辊偏心进行补偿．仿真实验表明该方法是有效的．

轧辊偏心的H_∞输出反馈鲁棒重复控制

针对轧辊偏心问题,用线性矩阵不等式(LMI)方法设计了用于轧辊偏心补偿控制的H∞输出反馈鲁棒重复控制器,首先引入动态输出反馈来保证闭环系统的鲁棒稳定性,把重复控制器设计问题转化为H∞动态反馈控制器的设计问题,采用变量替换法将非线性矩阵不等式转化为线性矩阵不等式并对其求解进而得到控制器参数.另外在采用上述控制器保证系统鲁棒稳定性的同时,通过在重复控制器中引入一个前向系数进一步改善和提高系统的动态性能与稳态控制精度.理论证明与仿真研究表明当系统对象参数存在摄动时,这种控制器仍能有效地补偿轧辊偏心对产品质量的影响.

神经网络自适应滤波在轧辊偏心控制中的应用

论述了一种具有偏心补偿能力的 AGC系统。它借助于神经网络自适应滤波提取偏心信号并以此信号为基础 ,消除偏心影响 。

关于轧机生产板材轧辊偏心控制优化研究

在板材的生产过程中,由于轧辊偏心扰动影响板材厚度的精度,而传统FFT算法在轧辊偏心控制中存在识别误差。针对上述问题,提出了一种基于单子带重构改进算法和比值校正法相结合的偏心信号重构新方法。首先采用单子带重构改进算法对偏心信号进行分频,并且有效的去除噪声,在信噪比低和频率相近时能够准确的提取偏心信号的频率及谐波个数,弥补了比值校正法对噪声敏感的弱点及对各谐波分量间隔大的要求。然后使用比值校正法对各次谐波幅值和相位进一步估计。仿真及实验结果表明,利用结合方法重构得到的轧辊偏心模型可以很大程度减小厚度波动,使轧辊偏心控制精度达到了补偿要求。

轧辊定位控制系统

简要介绍了轧辊定位系统的基本工作原理 ,论述了在大机械转动惯量、存在齿轮间隙。

轧辊修磨工序顺序安排的实践与探索

对于同一被修磨的轧辊,修磨工序的安排可以有多种。本文介绍了根据现有的生产条件,设备的性能、规格和精度等级,对轧辊修磨工序在一定范围内进行了讨论。通过对二条工艺路线的分析和比较,确定了一条适合自身条件和确保修磨质量、高效和低成本的最佳工艺路线。

铝冷连轧中的自动控制功能

本文介绍了在铝冷连轧机中的传动控制功能、成组控制功能和工艺控制功能,特别介绍了对最终质量影响较大的自动厚度控制和板型控制等控制功能。

Application of the Plate Crown Prediction

The program of the plate crown optimal prediction applied in the plate mill of Wuhan Iron and Steel(Group) Co. Ltd. is described. Optimal prediction is programmed in ALPHA 4000. The original profile, wear, expansion and deformation of work rolls are introduced into the program. The plate crown is controlled by the original profile of work rolls and the draft whose objective is the optimal plate crown. The run schedule is also optimized through the optimal prediction of the plate crown.

Modeling and identification of HAGC system of temper rolling mill

Including servo valve, hydraulic cylinder, mill and sensor and ignoring nonlinear factors, the linear dynamic model of hydraulic automatic gage control(HAGC) system of a temper rolling mill was theoretically derived. The order of the model is 4/4, and can be reduced to 2/2. Based on modulating functions method, utilizing numerical integration, we constructed the equivalent identification model of HAGC, and the least square estimation algorithm was established. The input and output data were acquired on line at temper rolling mill in Shangshai Baosteel Group Corporation, and the continuous time model of HAGC system was estimated with the proposed method. At different modulating window intervals, the estimated parameters changed remarkably. When the frequency bandwidth of modulating filter matches that of estimated system, the parameters can be estimated accurately. Finally, the dynamic model of the HAGC was obtained and validated based on the spectral analysis result.

Roll shifting strategy with varying stroke and step in hot strip mill

A new roll shifting strategy with varying stroke and varying step was investigated,Two characteristic parameters including cat ear height and gap contour smoothness were introduced to assess the effect of shifting strategy on roll wear,and the relation between characteristic parameters and shifting strategy was established.Both varying stroke and varying step can reduce cat ear height and gap contour smoothness,so the shifting strategy with varying stroke and varying step is better than the one with either varying stroke or varying step,Based on the effect of shifting control parameters on characteristic parameters of roll wear,the selection principle of these shifting control parameters was gained.A case study was conducted to validate the proposed roll shifting strategy,reducing uncontrollable quartic loading gap contour,improving strip profile and extending rolling length of a rolling campaign.

Numerical simulation and model of control-efficiency of thermal crown of work rolls in cold rolling

Aiming at accuracy control of the thermal crown of work rolls in cold rolling,new parameters such as regulation domain and control-efficiency factors were proposed and a numerical analysis model of the thermal crown of work rolls was established using finite difference method to study roll's thermal deformation.Based on simulation results,the influences of control-efficiency factors on thermal crown are presented and the thermal crown of work rolls is analyzed after taking sub-cooling of sprinkling beam into consideration.It has been found that the control-efficiency factor of any position on the roll's surface is linear function of the temperature and the control ability of water temperature is stronger than other control parameters.In addition,the verification of the model has been carried out based on the producing technology data in some factories and the numerical simulation results coincide well with the experimental data.Therefore,this work has important value for on-line control of roll's crown in cold rolling.

Identification and optimization for hydraulic roll gap control in strip rolling mill

In order to improve the control performance of strip rolling mill, theoretical model of the hydraulic gap control(HGC) system was established. HGC system offline identification scheme was designed for a tandem cold strip mill, the system model parameters were identified by ARX model, and the identified model was verified. Taking the offline identified parameters as the initial values, online identification using recursive least square was carried out with model parameters changing. For the purpose of improving system robustness and decreasing the sensitivity due to model errors, the HGC system based on generalized predictive control(GPC) was designed, and simulation experiments for traditional controller and GPC controller were conducted. The results show that both controllers acquire good control effect with model matching. When the model mismatches, for the traditional controller, the overshot will increase to 76.7% and the rising time will increase to 165.7 ms, which cannot be accepted by HGC system; for the GPC controller, the overshot is less than 8.5%, and the rising time is less than 26 ms in any case.