具有不确定性参数的轧机主传动系统自抗扰控制器设计

轧机主传动系统通常由直流电机驱动,其性能好坏直接影响板带材的产量和质量.针对轧机主传动系统存在不确定性负荷扰动和未建模动态的特点,首先建立了轧机主传动系统的模型,将不确定性负荷扰动和未建模动态视为一个综合扰动项,然后利用扩张状态观测器对综合扰动项进行观测和补偿,基于自抗扰控制技术设计了一个不依赖于对象模型的轧机速度鲁棒控制器.仿真结果表明:该控制器不仅有效地抑制了不确定负荷扰动的影响,同时对系统内部参数如电机转动惯量、电枢电阻等的摄动也具有较强的鲁棒性.     

Hamilton‐based adaptive robust control for the speed and tension system of reversible cold strip rolling mill

The adaptive robust control problem for the speed and tension system of reversible cold strip rolling mill is studied based on the Hamilton theory in this paper. First, the dissipative Hamilton model of the rolling mill system's speed and tension outside loop is built through pre‐feedback control, and then, dissipative Hamilton controllers are designed by utilizing the interconnection and damping assignment and the energy shaping method. Second, in order to realize tensiometer‐free control and adaptive robust control for the perturbation parameters and load disturbance, full‐order state observers and adaptive robust controllers are designed for the rolling mill system's speed and tension outside loop by using the “extended system + feedback” method. Third, robust controllers for the rolling mill system's current inside loop are designed based on the cascade control thought, so as to realize the tracking control for the speed and tension of reversible cold strip rolling mill. Theoretical analyses show that the resulting closed‐loop system is stable. Finally, simulation research is carried out on the speed and tension system of a 1422‐mm reversible cold strip rolling mill, and simulation results verify the validity of the proposed control strategy in comparison with the decentralized overlapping control strategy.     

模糊自适应PID反馈补偿控制在轧钢控制系统中的应用

由于轧机两侧液压压下系统的不一致导致带材横向厚度差分布不均匀,直接影响带材的板形质量,针对此问题,提出将模糊自适应PID控制器用于反馈回路中的补偿控制方案,提高轧机两侧压下动态同步的品质。仿真实验结果表明,此种方案能满足被控对象对高精度同步控制的要求。     

陷波滤波抑制轧机扭振

扭振是机械设备中普遍存在的问题,特别是在轧钢生产线的主轧机上体现得比较突出,破坏设备并对设备运行的稳定性造成较大影响.随着轧机的输出功率和转矩进一步增加,扭振问题显得更为重要.对轧机扭振的抑制是轧机控制系统的一个重要环节.结合日照钢铁1580mm热连轧工程,阐述和分析了轧机扭振的计算和运用陷波滤波抑制轧机扭振.     

Active compensation of roll eccentricity in rolling mills

This paper is concerned with the active compensation of the roll-eccentricity-induced periodic disturbances in the strip exit thickness of hot and cold rolling mills. The roll eccentricity may be caused by different reasons, e.g., inexact roll grinding or nonuniform thermal expansion of the rolls. The increasing demands on the thickness tolerances require new methods for the active compensation of the contribution of the roll eccentricity to the final thickness deviation. The presented method is based on the factorization approach over the set of stable transfer functions in combination with an adaptive least-mean-squares algorithm derived from the projection theorem. Here, the authors take advantage of the fact that the eccentricity-caused disturbance is periodic with a frequency proportional to the measured angular velocity of the rolls. Furthermore, it turns out that the presented concept fits the conventional control circuit of automatic gauge control in an optimal way. Simulation results for a cold rolling mill and measurement results for a hot strip mill demonstrate the feasibility and the excellent performance of the design     

1 800 mm铝箔冷轧机控制系统

采用全数字化、全网络化集散控制技术的1800mm铝箔冷轧机控制系统,实现速度、张力、厚度控制。介绍了卷径计算、线速度测量、张力控制、AGC系统的位置控制、压力控制、压力补偿控制的方法。采用高精度、快速响应的数字式速度控制,使该冷轧机的AGC系统具有先进、可靠、精度高的特点,可以将铝带的厚度控制在μm级,满足用户对冷轧铝带的高精度需求。     

20辊轧机板形辊驱动方案研究

可逆轧机板形辊与带材的不同步造成带材的表面划伤及卷径跳动,针对可逆轧机板形辊控制的工艺要求,在分析其原有控制原理的基础上,提出板形辊速度与带材速度不同步及张力波动的原因。通过对原有板形辊传动控制方案的改进及补偿转矩的优化,从而提高板形辊与带材的同步度,解决了卷径跳动及张力波动问题,提高了轧机运行的稳定性,从而有效地提高了带材的表面质量及产量。     

武钢一热轧改造后粗轧区控制系统

武钢一热轧的工艺布置方案为目前国内少有的3/4连轧方式,这种布置方案不仅使得轧线上粗轧区的长度大大超出半连轧布置方案,而且对粗轧区的自动化控制系统也提出了更多的要求,除了需具备一般热轧厂单机架粗轧机的所有功能之外,还必须具备连轧的功能.根据该厂的具体情况,设计了粗轧区控制系统.运行结果证明,控制系统稳定可靠、操作方便快...     

单机架可逆轧机轧制线调整系统的自动控制

深圳华美板材厂单架冷轧机轧制线调整系统采用了阶梯板和斜楔技术。通过应用轧制线标高调整系统的自动控制原理,建立一种轧制线标高调整系统的数学模型实现自动控制功能。使用该系统后,节省了电动压下电机及控制装置,缩短了换辊时间,改善了带钢板形,提高了轧制精度。     

Nonlinear control in rolling mills: a new perspective

This paper is concerned with the application of modern nonlinear control techniques to the thickness control in rolling mills. It turns out that the performance of the closed loop can be significantly improved by taking into account the essential nonlinearities of the plant to be controlled already in the controller design. These nonlinear control strategies totally differ from the common approach of linearizing the nonlinear system around a nominal operating point, because they are not limited to a more or less small neighborhood of the operating point, but are valid all over the operating range. Practically, these nonlinear control concepts are a possible answer to the trend of modern rolling mills toward tighter thickness tolerances, thinner final strip thicknesses, faster production rates and shorter off-gauge lengths. However, a straightforward application of the well established nonlinear control theory does not always lead to a control concept that is practically feasible. It is rather unavoidable to consider all the special features and properties of the plant. By means of the gap control of a mill stand with a hydraulic positioning system, the authors show in detail the advantages of a nonlinear control approach. Finally, simulation and measurement results demonstrate the feasibility and the excellent performance of the proposed design     

Feedforward Control of Plate Thickness in Reversing Plate Mills

As the plate thickness and temperature cannot be measured directly during rolling there is a strong need for well-adapted models. The product quality can be increased by making use of measured plate data that are available from a previous pass. A feedforward control strategy is proposed to improve the regularity of the plate thickness. An accurate forward slip model is used to track the current plate position even if no velocimeter signal is available. The performance of the controller is examined using an advanced simulation model of a finishing mill. The simulation studies are based on measured plate data     

A novel real-time fuzzy-based diagnostic system of rolleccentricity influence in finishing hot strip mills

This paper proposes a method for the diagnosis of the influence of roll eccentricity on the strip thickness at the exit of a finishing hot strip mill (FHSM). Each strip thickness defect on exit is related to a roll of the FHSM, allowing the implementation of an optimal policy for the substitution and maintenance of the rolls, thereby maintaining the required quality level of the strip. This policy allows the minimization of roll changes and the concentration of several changes at the same time, reducing production costs. Fuzzy logic is used to compare spectra, looking for common patterns, which allows for a totally automated diagnostic system. Moreover, an innovative estimate of roll eccentricity based on a least-squares algorithm has been developed, which provides higher accuracy than classical algorithms, as well as a drastic reduction in the time required to perform eccentricity tests     

Method for correction of gauge interference of the head-strip section in a system for automated controlling of the thickness of a broad-strip hot-rolling mill

To compensate for gauge interference caused by increased temperature of the head-strip section during milling on a broad-strip hot-rolling mill, a method for automated correction of thickness is proposed. Its essence lies in additional separation of the rolls during rolling of the head section with its subsequent return into the specified position for rolling the main strip length. The structure of the system for automated controlling, which implements this method, is considered. Rational parameters for correction of the roll space for the strips of diverse assembly are substantiated. The results of experiments performed at roll 2000 of the Magnitogorsk Iron and Steel Works are presented.     

High-Speed DC X-Ray Thickness Gauging of Metal Strip

With the progressively higher rolling speeds employed by manufacturers of metal strip and the requirements of closer gauge tolerance by the metal strip users, it has become increasingly important to have available a high-speed thickness-measuring device. Such a device can be a useful tool in analyzing high-speed mill variations as well as providing a low-noise high-accuracy signal for automatic control of thickness.     

The advanced set-up and control system for Dofasco's tandem coldmill

The new coupled pickle line and cold mill (CPCM) has been processing steel since December 1991 at Dofasco Inc. in Hamilton, Ontario, Canada. This mill rolls both sheet and tin plate. The work rolls for the last stand are often textured by grit blasting to roll “matte” finished strip. A new computer-targeted control system was developed for the roll speeds and gaps, specifically for matte rolling. The new set-up system uses Stone's model, which is more appropriate for the limited reductions evident with the rougher rolls. Conventional automatic gauge control (AGC) systems using thickness measurements after the last stand are limited in performance by the effect of long transport delays. These limitations are particularly critical during mill acceleration and deceleration. The use of a thickness gauge before the stand with matte rolls allows the development of AGC systems using shorter control loops for final gauge control. The AGC system uses a Smith predictor for transport lag, (phase shift), and compensation. The combination of the shorter AGC loop and the Smith predictor allows higher gains to be used in the control system. This set-up and control system has contributed to Dofasco's position as a market leader in thickness performance     

带钢表面粗糙度在线检测技术最新进展

表面粗糙度作为冷轧带钢重要的一项表面质量指标,其在线检测方法研究已成为高品质汽车板带产品生产的关键技术之一。传统的带钢表面粗糙度检测手段触针法存在离线测试、损伤表面、响应速度慢等问题,使得基于光学作用机理的光切法、光干涉法、散斑法、散射法等在线实时检测技术得到关注并发展迅速。近年来,带钢表面粗糙度的在线检测技术在原理推导、模型构建、样机实验、分析校准等方面取得了长足的进展,但冷轧带钢平整作业的轧辊控制(如辊形、运行速度等)与表面粗糙度在线检测精度之间的矛盾仍然是实时测控的难点问题。从带钢表面粗糙度在线检测的实际需求出发,分析理论研究成果,比较相应检测设备的特点和适应性,提出有效解决实时检测难点问题的可行方案,并对国内外带钢表面粗糙度在线检测的理论与实践发展趋势进行展望。     

Improved rolling mill automation by means of advanced controltechniques and dynamic simulation

This paper describes the simulation of a multiple-stand hot strip mill and its application for the development of complex control strategies. Both controlled system structure and control functions are explained. The application of advanced control techniques and dynamic simulation improves the thickness tolerances drastically. The results show that the major contribution stems from the feedforward system based on thickness and temperature identification. Extensive dynamic simulations enable the efficient realization of the theoretical concepts as practical solutions. Simulation results are shown     

State-dependent Riccati equation approach for optimal control of a tandem cold metal rolling process

The tandem cold rolling of metal strip is a large multiinput-multioutput process that presents a difficult challenge to the control designer because of the following factors: 1) the complex interactions between the process variables; 2) the nonlinearities; and 3) the interstand time delays that change significantly with the mill speed. Control systems using the present technology have produced an acceptable product but are limited in their capability for improvement in performance and robustness, and therefore, there is a need for a better approach. It is considered that the state-dependent algebraic Riccati equation technique for the control of nonlinear systems that has been quite successful in the aerospace industry might fulfil this need. This paper presents the results of an initial work performed to investigate the theoretical and applied aspects of this technique for the control of the tandem cold rolling mill. In this paper, nonlinear state space equations are derived from a mathematical model of the mill, and a controller using the state-dependent Riccati equation approach (with trims) is developed. By simulation of typical operating conditions, the controller, when coupled to the model, is shown to be effective in reducing the effects of disturbances in entry strip thickness and hardness.     

轧机液压伺服位置系统的自适应输出反馈控制

针对具有不可测状态、未知参数和非线性的轧机液压伺服位置系统,提出一种基于高增益观测器和参数估计器的自适应输出反馈控制算法.所构造的高增益观测器不依赖于系统输入和参数估计值,它只用于估计系统状态,所设计的动态反馈控制器包括:用于保证系统稳定性的主反馈部分和抵消外部扰动和一些不确定性的补偿部分.理论分析表明,所提出的控制算法能够保证闭环系统的所有信号有界,且系统状态及其估计误差的最终收敛边界依赖于观测器的高增益值.以某650 mm可逆冷带轧机液压伺服位置系统为例进行仿真,仿真结果验证了所提出算法的有效性.     

激光测厚仪在锂电池极片生产中的应用

介绍C架扫描方式激光在线测厚仪在锂电池极片涂布/滚压生产中的应用情况。该仪器可以实现稳定的对动态极片的测量精度±1.0μm(分辨率0.1μm)。极片生产厂通过建立在大量的实测厚度数据基础上的规律性总结,可以对涂布/滚压生产、设备、工艺乃至材料准备形成十分重要的指导意义,从而在很大程度上提高生产效率和效益。