The results shown in Table 1 demonstrate that the optimized schedule 3 in Table 1 is the best of all four schedules, including the empirical schedule. The total cost is the lowest when an equal importance factor, i.e. weight coefficient, is considered. For industrial situations, the three weighting coefficients can be assigned on the basis of the current practical situation.
4. Conclusions
An optimal rolling scheduling method is introduced here, which aims at achieving uniform power distribution, maximum safe level of strip tension, and good flatness. The results generated from the case study show that the proposed GA-based optimization approach has the potential to significantly improve empirically derived scheduling parameters for tandem cold rolling mills. With the GA-based optimization procedure, a considerable cost reduction can be obtained. The numerical evaluation also shows that the GA-based evolutionary searching is efficient, and has the potential to handle on-line scheduling. The power distribution of the tandem cold rolling mill is more uniform than those generated from the experience-based scheduling. Moreover, the shape achieved by the optimized schedules is likely to be improved. The tension under the optimized schedules 2 and 3 in Table 1 is more likely to be kept midway between the upper and lower limits. The numerical experimental results show that the proposed approach is an efficient way of solving rolling scheduling problems.
Further work will focus on the on-line adaptation capability due to changes in rolling conditions such as threading, tailing out, and the passing of a weld through the mill, and of strip properties such as entry thickness, hardness, etc.
面向冷连轧机轧制规程的启发式优化设计
摘要:调度冷连轧机机架间的仪表,测定指定产品的压力和速度。最佳计划应该使吞吐量最大化和经营成本最小化。本文提出了一种基于遗传算法的优化过程中的冷连轧机的调度。启动优化程序,从逻辑上盯着D点的经验轧制附表D,达到成本的最佳时结束。基于功率分布,张力,带材平直度的考虑和轧制的制约,构造成本函数,引导启发式遗传算法的搜索。实验表明,所提出的方法比基于半经验公式更有前途。从一个案例研究表明,该方法可以显着提高冷连轧机的经验得出的设置。©2000爱思唯尔科技有限公司保留所有权利。
关键词:轧制计划;进化算法;冷连轧;工艺优化
一. 介绍
由于现在的高吞吐量,高质量和低废品损失的产品产品,使冷连轧机的自动化系统不断被提高。为了巩固在全球市场上的竞争优势,许多钢铁企业都进行最大限度地减少浪费,从而降低制造成本。冷连轧机的操作中的,轧制调度是一个重要的方面。它定义了支架减少,张力,轧制力,轧辊扭矩,轧机的最大速度和线程的调整。优化调度应该有改进厚度,表面光洁度和产品形状的性能。
在过去的二十年中,只有少数论文已经解决了的轧制调度问题,特别是对冷连轧。早期的工作,在冷连轧机轧制调度系统的发展中,实现了正确的输出和良好的形状。被描述为一个约束两点边界值问题就解决了使用共轭梯度和投影技术的问题。优化问题定义的成本函数包括条带形状成本,张力成本和热冠成本。虽然从优化的排程生成的结果都优于那些原始的经验排程,在不考虑电源的成本情况下,冷连轧机均匀的功率分布是可取。此外,计算的成本主要依赖于一些轧制参数的线性系数的线性方程组。虽然共轭梯度是在实践中经常使用的方法,即使成本函数的优化问题不是凸面的,有理由相信,此类计算导致一个局部最小值的计算。当时的计算设备的计算能力限制。厄兹索伊他们采用了称为爬山算法的非线性规划方法优化轧制的热轧过程的排程。结果表明:虽然在一个封闭的形式不能得到解决,因为定义方程和振幅上的系统变量的约束的非线性优化问题,它可以在数字计算机上数值求解非线性规划。然而,采用的非线性规划方法的收敛行为中是直接受初始搜索点所使用的。其他一些非线性规划方法,如连续二次规划,也有一些缺点,除了增加了复杂性(导数的计算等),如局部最小的问题,不保证收敛,和昂贵的计算成本。作为一个智能的搜索机制,遗传算法(GA)具有潜在的,足够灵活的克服上面提到的缺点。 冷连轧机轧制规程英文文献和翻译(9):http://www.youerw.com/fanyi/lunwen_1229.html