Computer controlled galvanizing

In the galvanizing process zinc is coated onto the steel strip to inhibit rusting. Excess zinc is used to ensure that the finished product exceeds coating quality standards. Reducing the excess coating to a minimum while maintaining product quality can significantly reduce a company's zinc bill.A computer based coating-mass control system, installed on a galvanizing line, has reduced zinc consumption by thirteen percent, saving in excess of one million dollars annually. The same system has been installed in a zincalume line with similar results.The most significant time constant in the process is the transport delay between coatingmass control and measurement. Feedforward control, using a simple model and a table of adapted constants, compensate for this during major changes in process conditions. Feedback control, using a self-adapting linear incremental model, maintains the coating-mass within range during steady-state conditions.     

连续热镀锌线气刀吹锌过程中锌波纹产生的大涡模拟

为寻求连续热镀锌线气刀吹锌过程中带钢上出现锌波纹的原因,采用大涡模拟（Large Eddy Simulation,LES）方法数值求解三维非稳态气刀射流湍流流场,并结合带钢表面的镀锌层厚度的零维预测模型研究锌波纹产生的机理．结果表明,在气刀射流冲击区域两侧有交替成对出现的漩涡,造成带钢表面的压强和切应力周期性波动分布,从而产生锌波纹．     

Coating weight control on ArcelorMittal’s galvanizing line at Florange Works

ArcelorMittal’s hot dip galvanizing line at Florange has developed and commissioned its own coating weight control system. This system automatically controls air-knife pressure and position to give a constant and uniform zinc coating in accordance with customer-order specifications through a model-based feedforward controller and two feedback controllers. Moreover, continuous adaptation of the knife-to-strip distance allows a fast and accurate response to process fluctuations under the entire range of operating conditions. Due to speedy acceptance of this system by line operators, large and rapid benefits, i.e. quality improvement and zinc savings, have been achieved immediately after it was put into production.     

Coating mass control system design for a continuous galvanizing line

The structure of a typical computer-based coating mass control system is derived which incorporates feedback and feedforward controllers based on recently developed adaptive mathematical models for the jet stripping process. Using conventional design techniques, three alternative types of feedback control algorithm are invstigated. The ‘pulse-and-wait’ algorithm is recommended for computer control applications due to its ease of implementation. Typical simulation results are presented for a range of strip speeds with and without errors in the model parameters. Emphasis is placed on the need to adjust some of the controller settings as a function of process conditions. A computer control system based on the previously outlined concepts has been commissioned on a modern continuous galvanizing line operating at speeds up to 170 m/min. Typical results are given illustrating the improvements achieved from manual and automatic control after the installation of a coating mass gauge.     

基于核偏最小二乘的锌层重量预测模型

为了给带钢热镀锌生产的质量控制提供必要的决策支持和分析手段,针对气刀对锌层重量的控制工艺,提出了基于核偏最小二乘回归的锌层重量预测模型。利用核函数将低维空间的非线性回归转化为高维空间的线性回归,克服了实际生产工艺中非线性因素对预测模型的不利影响。应用鞍山钢铁集团公司带钢热镀锌的生产实际数据进行验证,结果表明,基于核偏最小二乘的锌层重量预测方法与线性偏最小二乘、BP神经网络等方法相比,具有更好的预测精度。     

Performance assessment of control systems in rolling mills – application to strip thickness and flatness control

This contribution takes the control performance monitoring (CPM) technology into a new industrial area, the metal processing, where not much work has been done before. It is shown how to explore not yet discovered opportunities for controller performance improvement in this industrially interesting field, where special aspects have to be considered. This includes online vs. batch-wise performance evaluation, time-based vs. length-based assessment, and oscillation diagnosis. The paper presents two industrial case studies of the performance evaluation of control systems in a tandem cold rolling mill: (1) a feedforward/feedback strip thickness controller; and (2) an internal model control of the strip flatness. Routine operating data are analysed to obtain the performance monitoring metrics in terms of minimum variance index, oscillation index, and to suggest improvement measures. A monitoring tool for calculating and displaying the performance indices has been developed, and tailored to the applications in this field. The results indicate that tuning the feedback thickness controller is suggested to better handle entry thickness disturbances for specific coils. The performance of the flatness controller is found to be satisfactory, thus no actions are needed.     

Real-Time Flatness Inspection System For Steel Strip Production Lines

This paper describes the development of a flatness inspection system, integrated in the control process of a hot strip mill in the steel industry. The objective of the system is to calculate flatness indexes for every strip, comparing the length of its lateral profiles with the central length. The reconstruction of the profiles is based on a nonlinear triangulation technique. Images of the steel strip, at high temperature and high speed, are sampled every 2 ms at five different points and are processed on-line in order to calculate height displacement values of the strip, which allows the calculation of final flatness indexes for the steel strip. The measurement method developed introduces an innovative geometry in the disposition of the optical elements which increases the measurement range without reducing precision. It also includes a tracking system to compensate for the effects of lateral displacements of the strip. The flatness inspection system has been implemented using a heterogeneous distributed computer system.     

带钢磁悬浮防抖系统的研究

在镀锌生产线中垂直带钢水平晃动会造成镀层不均。基于磁悬浮技术能够实现无接触稳定的特点,研制了用于带钢防抖的磁悬浮系统。分析建立了系统的数学模型,设计了PID控制器。研究设计了包括传感器、控制器、功率放大器的磁悬浮电控系统。在模拟试验台上对系统的性能进行了试验研究。通过试验证明了该磁悬浮系统能够稳定地悬浮带钢,减小带钢在外力扰动下的振幅和回到稳态所需的调节时间,并且在激振试验中成功地使带钢的振幅减小了71.4%。     

过程控制计算机的超薄热带板形控制模型

从机械设备配置和机电控制手段阐述超薄带钢生产的板形控制的特点,重点是板形过程控制系统的控制方法及最终的控制效果。板形控制数学模型的核心数学模型控制程序是PC和弯辊设定模型程序,即SAU数学模型程序。该模型通过五次预计算及三次设定PC角和弯辊力,实现控制板带产品的凸度和平直度,使其最终达到目标凸度及目标平直度值。     

基于递阶遗传算法的RBF神经元网络板形板厚综合控制

该文首先用递阶遗传算法（HGA）设计RBF神经网络，不仅可以同时确定网络参数（连接权、隐节点中心和宽度），而且解决了网络拓扑结构的优化训练问题，而后针对板带材轧制是一个复杂的非线性过程，板形控制（AFC）和板厚控制（AGC）又是相互耦合的一个综合系统等特点，建立了基于过程最优的权值在线自学习算法的RBF神经元网络的板形板厚多变量综合控制系统，仿真结果证明了此AFC－AGC控制系统具有良好的自适应跟随和抗扰性能，其控制效果优于传统的解耦PID控制。     

带钢连续热镀锌退火过程的模型化

针对大型冷轧带钢连续热镀锌退火过程的模型化和控制难题，本文以目前国内最先进的宝钢热镀锌生产线为对象，建立了用于实进控制的两类新疑数学模型，带温分布模型和带温跟踪模型，仿真和工业运行效果良好。     

宽带钢厚度模型的研究与优化

介绍莱钢宽带钢厚度模型的优化,以改善板形,提高控制精度.     

首钢京唐1580热连轧精轧机活套高度及张力控制

在带钢热连轧生产过程中,精轧机组的技术装备水平和控制水平是决定产品质量的关键因素。而精轧机架间活套控制和张力控制水平则直接影响了轧制能力的高低,对带钢宽度、厚度、平直度、板型等关键性能指标和力学性能有着至关重要的作用。     

RBF神经网络的板形预测控制

由于板带轧制的环境十分复杂,如温度的变化是无法避免的干扰,以及HC轧机液压弯辊系统的非线性和不确定性,使得按传统理论建立的模型和控制方法都难以达到理想的效果.针对这一问题,提出了一种基于径向基函数(RBF)神经网络的模型预测控制方案应用于带材控制中,以提高带材的成材率,充分发挥液压弯辊力对板形的调整作用,改善轧机系统的动态特性.仿真结果表明了该控制系统的性能良好,有较强的抗干扰能力和较好的鲁棒性和快速性.     

热轧带钢卷取温度联合控制算法设计与仿真

在热轧带钢生产线上,卷取温度的精确控制对带钢质量是至关重要的。详细研究了一个实际的热轧带钢卷取温度控制系统。建立了一种简化的动态控制模型,并用一个改进的遗传算法在线调整模型的参数。基于该模型提出了一个包括冷却反馈控制、前馈及自适应联合控制算法的控制器。通过建立一个更精确的仿真系统,达到指导现场生产的目的。实践结果证明提出的控制方法是有效的,仿真系统也具有较大的实际意义。     

唐钢2#镀锌线连续退火炉自动化控制系统

退火的主要目的是通过密闭的高温加热和无氧条件的冷却将钢带上的氧化层和各种杂质除掉,从而保证钢带镀锌的质量。为此,介绍了唐钢2#锌生产线连续退火炉的自动化控制系统组成及其功能。由于采用了先进的硬件、软件配置及自动化控制技术,退火炉的各项参数均达到了预定指标,为后工序的带钢镀锌提供了良好条件。     

一类轧机的板形最优化控制方法

分析了常规四辊CVC轧机板形控制的原理,结合生产实际给出了板形的最优化控制策略及其数学模型,该方法具有不需对板形缺陷进行识别,不用基于最小二乘法的曲线拟合的方法进行板形缺陷的识别的特点.对调节装置的调节量及多个调节装置的调节量采用联合求解方法,具有快速达到最佳优点,可推广到其它同类轧机的板形控制中去.     

热连轧机厚度最优前馈控制研究

热连轧机前馈控制是减小带钢厚度公差的有效方法。本文采用前机架带ＡＧＣ的厚差预报和贝尔曼动态规划最优控制方案，在本钢１７００ｍｍ热连轧机上实验成功。文中对交馈系统做了深入的分析研究，提出参数选择原则和方法。     

Precise piston trajectory control for a free piston engine

A free piston engine removes the mechanical constraint on the piston motion by eliminating the crankshaft. The extra degree of freedom offers many advantages for reducing fuel consumption and emissions. Nevertheless, stability and robustness of the engine operation has been affected in the meantime. To ensure smooth engine operation, an active motion controller, which utilizes robust repetitive control, was developed previously to regulate the piston motion of a hydraulic free piston engine to track pre-defined trajectories. However, the long piston stroke length, high operating frequency and system nonlinearity impose challenges to precise piston motion control. Therefore, feedforward controllers are investigated in this paper to complement the repetitive control to further improve the tracking performance. The first feedforward design involves the inversion of a linear plant model that describes the dynamics of the engine operation, and the second design is based on the flatness approach, which involves the inversion of a nonlinear model of the system. The two feedforward controllers are designed and implemented on the free piston engine. The experimental and simulation results demonstrate the effectiveness of the proposed control under various operating conditions and reference piston trajectories.     

连续热镀锌退火炉控制系统的设计与实现

针对大型冷轧带钢连续热镀锌退火过程模型化及控制这一技术难题，本文以某实际系统为背景，提出了一种具体的设计与实现方案。本系统的研制成功地填补了国内空白，具有显著的经济效益和社会效益，对于其它类似的大型引进项目的技术消化和技术改造也有一定的参考价值。