Industrial shape detecting system of cold rolling strip

A high-precision shape detecting system of cold rolling strip is developed to meet industrial application, which mainly consists of the shape detecting roller, the collecting ring, the digital signal processing (DSP) shape signal processing board and the shape control model. Based on the shape detecting principle, the shape detecting roller is designed with a new integral structure for improving the precision of shape detecting and avoiding scratching strip surface. Based on the DSP technology, the DSP shape signal processing circuit board is designed and embedded in the shape detecting system for the reliability and stability of shape signal processing. The shape detecting system was successfully used in Angang 1 250 mm HC 6-high reversible cold rolling mill. The precision of shape detecting is 0.2 I and the shape deviation is controlled within 6 I after the close loop shape control is input.     

适应变速轧制的精细化轧件温度计算和控制模型

针对因变速轧制和复合冷却带来的卷取温度模型预报精度降低的问题,以热输出辊道上的冷却设备布置信息和辊间冷却换热形式为出发点,采用Crank-Nicolson(C-N)六点格式有限差分方法构建轧件轧后冷却温度计算模型;以前馈为主、反馈为辅,不断进行自学习来对轧件冷却温度进行控制,在精轧出口按照固定时间周期对轧件进行分段采样和前馈设定,在卷取入口按照长度进行分段采样和周期性反馈控制;为使模型适应升速轧制和因终轧温度控制所带来的速度扰动叠加的速度变化,对轧件在冷却区的运动进行精确的位置跟踪,并在冷却区中增设速度补偿区,对设定的冷却规程进行更新以补偿升速带来的冷却不足或降速引起的过冷.新的卷取温度模型以辊间冷却为计算单元,可有效地集成不同的冷却形式,并对变速轧制过程进行有效适应.自现场应用以来,卷取温度设定精度和控制稳定性大幅度提高.     

Work roll thermal contour prediction model of nonoriented electrical steel sheets in hot strip mills

The demands for profile and flatness of nonoriented electrical steels are becoming more and more severe. The temperature field and thermal contour of work rolls are the key factors that affect the profile and flatness control in the finishing trains of the hot rolling. A theoretic mathematical model was built by a two-dimensional finite difference to calculate the temperature field and thermal contour at any time within the entire rolling campaign in the hot rolling process. To improve the calculating speed and precision, some special solutions were introduced, including the development of this model, the simplification of boundary conditions, the computation of heat transfer coefficient, and the narrower mesh along the edge of the strip. The effects of rolling pace and work roll shifting on the temperature field and thermal contour of work rolls in the hot rolling process were demonstrated. The calculated results of the prediction model are in good agreement with the measured ones and can be applied to guiding profile and flatness control of nonoriented electrical steel sheets in hot strip mills.     

热轧带钢层流冷却温度优化控制策略研究

在热轧带钢生产过程中,卷取温度是影响成品带钢性能的重要参数之一,其精度的高低对带钢质量至关重要.为保证产品具有良好的性能,采用层流冷却装置对热轧后的板带进行冷却控制,喷水系统的设定是层流冷却过程控制的关键.在冷却过程中带钢的温度不能在线连续检测,其过程具有强非线性和时变性,而且在冷却过程中存在相变,因此难以建立精确的数学模型去描述这一冷却过程.随着带钢厚度,精轧出口温度和轧制速度的变化,单独的前馈/反馈控制很难满足高精度的温度控制需要.在本文的研究中,一系列层流冷却控制策略被采用,包括前馈/反馈控制,自适应算法,以及控制带钢整体温度的均匀性策略.实践应用表明这些控制策略得到很好的检验,能有效地提高卷取温度的控制精度和均匀性.     

板带钢头部翘曲的有限元分析

为了减轻轧件头部翘曲给轧制过程带来的影响,根据现场轧制工艺,采用弹塑性有限元法建立了三维非对称轧制有限元模型。利用该模型分析热轧板带钢生产过程中轧件头部翘曲的产生机理,并研究了不同轧制工艺下的辊速比、上下表面温差、不同摩擦系数对轧件头部翘曲的影响规律。结果表明,随着压下量的增大,轧件头部翘曲量的增大趋势减缓,采用不同的配辊方案（异径比）可控制其头部翘曲的现象。     

升速轧制对热轧带钢层流冷却出口温度的影响

采用传热学原理建立了层流冷却温度有限差分模型,并用现场实测数据对水冷换热系数进行了自适应修正.对德盛1 150 mm热轧带钢层流冷却过程的温度变化进行了数值模拟,建立了一套层流冷却温度仿真系统,分析和研究升速轧制时带钢在层流冷却中温度变化的趋势.结果表明,层冷出口温度受带钢的速度影响较大,在升速过程中,如果不采用集管动态喷水调节,带钢温度出现前低后高的现象,并且随着加速度的增加带钢前后温差越大.以此为依据,现场过程自动化系统L2级硬件采用过程服务器,基础自动化系统L1级硬件采用西门子PLC,L2级和L1级软件分别在C++和Step7V5.4下编程实现,并采用了带钢头尾宏跟踪和过程自动化系统采用带钢样本微跟踪的控制策略,对处于变速及高速运动中的带钢沿长度方向逐点实施控制,用动态调节的冷却集管系统来保证在速度变化期间带钢层流冷却出口温度的稳定性.     

智能算法在双辊铸轧过程铸轧力计算中的应用

在双辊铸轧过程中,铸轧力的控制是铸轧过程稳定进行和提高薄带质量的关键.为了控制铸轧力,必须建立铸轧力计算数学模型,本文采用了一种基于贝叶斯方法的前向神经网络训练算法以提高网络的泛化能力,在网络的目标函数中引入了表示网络结构复杂性的惩罚项,融入“奥克姆剪刀”理论,避免了网络训练的过拟合.将上述网络应用于铸轧过程的铸轧力计算,具有很高的计算精度,同时在收敛速度、稳定性和泛化能力方面都优于传统的BP神经网络.     

Improvement of prediction model for work roll thermal contour in hot strip mill

Though high accuracy of the thermal contour was obtained while adopting finite element method, it could not meet the real-time requirement. One-dimensional finite difference method could realize real-time control in the case of neglecting both the circumferential and radical heat exchange, but the over-simplified modes resulted in poor accuracy. And two-dimensional full explicit difference was also limited in practical application since its time step was restricted to keep the model stable. Consequently, a new method of alternating direction finite difference was introduced and discussed in the model’s stability, calculating speed and precision. Specific work roll after one real rolling unit was researched, The result shows that error of temperature on work roll surface between measured and calculated values is within 5 °C. The influence of rolling rhythm and strip width on thermal crown was also studied. The conclusion is verified theoretically and practically that it can maintain absolutely stable and meet the online requirement.     

积分型线性综合最优控制原理及仿真实验

对发电机端电压偏移量施加积分控制时,考虑到发电机励磁系统、调速系统的控制, 推导出了发电机的积分型线性综合最优控制规律(ILIOC),并与只考虑发电机励磁系统、调速系统控制的发电机线性综合最优控制规(ILIOC)进行了比较。仿真结果表明:在提高系统稳定极限和改善系统动态特性方面,ILIOC与LIOC具有相同能力。同时ILIOC能消除发电机端电压的稳态误差,提高了控制精度,改善了系统运行水平。     

Lubrication in strip cold rolling process

A lubrication model was developed for explaining how to form an oil film in the deformation zone, predicting the film thickness and determining the characteristics of lubrication in the strip rolling process, combined with the knowledge of hydrodynamic lubrication and rolling theories. Various mineral oils with viscosities from 0.032 to 1.6 Pa.s were used to obtain different film thicknesses in the strip cold rolling. Results from the experiment and calculation show that the oil film forming in hydrodynamic lubrication is up to the bit angle and a higher rolling speed or a higher rolling oil viscosity. The mechanism of mechanical entrainment always affects the film thickness that increases with the rolling oil viscosity increasing or the reduction rate decreasing in rolling.     

一类非匹配不确定纯反馈非线性系统新型变幂次趋近律滑模控制

针对以熔化极气体保护焊（gas metal arc welding,GMAW）为代表的一类非匹配不确定纯反馈非线性系统的输出问题,提出一种基于变幂次趋近律的滑模控制方法。首先,采用滑模微分器得到含系统非匹配不确定性干扰的输出一阶导数。得益于终端滑模有限时间稳定的性能,该方法具有估计精度高、估计误差收敛速度快的优点。然后,提出一种新型的变幂次趋近律,并证明在相同增益下,其趋近速度均快于现有各种趋近律,且具有自适应调节趋近速度的能力,既保证了在全局范围内系统轨迹有限时间趋近滑模面,又避免了在滑模面附近出现抖振。最后,采用变幂次趋近律滑模变结构控制方法和传统趋近律滑模变结构控制方法分别对带有非匹配干扰的GMAW中的弧长进行控制仿真,并对比弧长跟踪效果,分析稳态误差。结果表明,变幂次趋近律滑模变结构方法能够有效的提高系统收敛的快速性,滑模控制方法对于非匹配不确定非线性系具有强鲁棒性。     

1420 mm轧机板形预设定计算仿真系统设计

为了提高板形预设定计算的精确度,针对某厂1420 mm冷连轧机板形控制系统的预设定计算模型进行仿真计算.将板形预设定模块从原Solaris系统移植到Windows模拟机上,建立数据信号输入和输出接口,实现板形预设定离线模拟计算,为板形设定计算提供研究和开发平台.其预计算结果的精确度与实际测量值十分相近,直接影响到基础自动化层(L1)的控制,最终提高了带钢板形的质量.     

数字定长裁断控制模型及算法

通过对瓦楞纸板横切机、印刷机的裁单张单元和型材锯切设备的分析,提出了2种类型定长裁断控制系统的模型和算法.其中横切机、印刷机的裁单张单元属圆周运动定长裁断,型材锯切设备属直线运动定长裁断.在对上述类型设备的工作原理分析建模的基础上总结并提出了以位置控制为中心的控制算法,相对传统基于模拟量控制的速度跟随系统算法有精度高、速度快、抗速度波动能力强和易维护等特点.为2种定长裁断控制系统的开发提供了控制流程,可直接采用数字伺服驱动器给予实现.实践证明,这一控制方法是可行的.     

基于MRAS磁链观测、转速估计的无速度传感器异步电机矢量控制系统

针对传统矢量控制系统磁链观测不准,且需要速度传感器的问题,提出了一种基于MRAS磁链观测、转速估计的无速度传感器异步电机矢量控制系统。介绍了磁链观测、转速估计的MRAS结构,并运用Popov超稳定理论推导出了其对应自适应律,建立了实验系统。实验结果表明,该矢量控制系统在启动、调速、稳态运行时具有良好的静、动态性能,是一种高性能的交流调速系统。     

Anti-Windup Control Strategy of Drive System for Humanoid Robot Arm Joint

To address the problems of torque limit and controller saturation in the control of robot arm joint,an anti-windup control strategy is proposed for a humanoid robot arm,which is based on the integral state prediction under the direct torque control system of brushless DC motor.First,the arm joint of the humanoid robot is modelled.Then the speed controller model and the influence of the initial value of the integral element on the system are analyzed.On the basis of the traditional anti-windup controller,an integral state estimator is set up.Under the condition of different load torques and the given speed,the integral steady-state value is estimated.Therefore the accumulation of the speed error terminates when the integrator reaches saturation.Then the predicted integral steady-state value is used as the initial value of the regulator to enter the linear region to make the system achieve the purpose of anti-windup.The simulation results demonstrate that the control strategy for the humanoid robot arm joint based on integral state prediction can play the role of anti-wind-up and suppress the overshoot of the system effectively.The system has a good dynamic performance.     

一种积分型切换函数的滑模控制算法在倒立摆系统中的仿真应用

针对实际控制系统的非线性和某种程度上存在扰动的特点,采用基于积分切换函数的滑模变结构控制算法不仅能减小由于扰动带来的稳态误差,同时对抑制抖振现象有很好的效果。另一方面为了使系统能够快速到达切换面,在指数趋近律的基础上增加变速部分保证整个趋近过程用时很短。将此算法应用到一级倒立摆系统中进行仿真验证,仿真结果显示了此算法克服抖振的效果。     

非对称轧制力能参数与带钢张应力分布规律

为深入了解带钢轧制过程中非对称因素对轧制力能参数与带钢张应力分布的影响,应用ABAQUS非线性有限元软件对轧制过程进行二维建模及仿真分析,以轧辊驱动方式非对称、上下工作辊与带钢间接触摩擦润滑条件非对称以及存在异步轧制等3种非对称因素作为研究对象,计算并分析上述非对称因素及其程度对于轧后带钢内部张应力分布、轧制力以及轧制扭矩的影响规律,进而定量分析与比较3种非对称轧制因素对于轧制过程中的力能参数和厚向张应力分布规律的影响程度. 仿真计算表明：3种非对称轧制状态都会导致轧后带钢厚向张应力分布的不对称;3种非对称轧制状态都会明显改变轧制过程力能参数大小;与相应对称轧制状态相比,有些非对称因素可以不同程度地降低轧制力和轧制扭矩. 轧制过程中的非对称因素从不同的角度来分析,是利弊共存的.     

无刷直流电机模糊PI控制系统

设计了模糊比例积分(Fuzzy-PI)控制器,用以实现对无刷直流电机的双闭环调速。给出无刷直流电机的数学模型,阐述了模糊PI控制器的构建过程,使用matlab软件搭建无刷直流电机的控制系统,分析重点模块,对控制系统进行仿真实验得到了仿真图形。仿真结果表明模糊PI控制器能够加快系统响应时间,减小超调,提高系统的控制精度,具有更好的应用价值。     

模糊积分控制在位置随动系统中的应用

位置随动系统要求具有较快的动态响应速度和较低的稳态误差。在模糊控制位置随动系统的基础上,引入积分控制方法,实现了位置随动系统的模糊积分控制。在系统的动态过程中,利用模糊控制的快速响应能力保证位置随动系统具有较快的动态响应速度;系统进入稳态以后引入积分控制,提高位置随动系统的稳态精度。将模糊积分控制方法应用于KSD-1型位置随动系统,实验结果表明该方法具有稳态精度高、响应速度快、超调量小的特点。     

模糊PID算法在回转窑的喂煤量—烧成带温度控制系统中的应用

喂煤量-烧成带温度控制系统是回转窑生产的一个重要组成部分,但其具有大惯性、纯滞后、非线性等特点,常规PID控制算法难以对其生产温度进行准确的控制。文章提出的模糊PID控制器是将模糊控制与传统PID控制相结合,用模糊控制理论在线整定PID控制器的比例、积分、微分系数。仿真结果表明,该控制器在响应速度、稳态精度等方面均优于常规PID控制器。