板坯最优倒垛问题的有效启发式算法

Effective heuristic algorithm for optimal turned-out slab pile problem

板坯库用于存放由炼钢 -连铸工艺阶段产生的、供热轧生产阶段进一步轧制成带钢或钢板的板坯 .一个板坯库中可分为多个逻辑区域 ,每个逻辑区域又进一步分为多个垛位 .同一垛位的板坯之间是叠放的 .最优倒垛问题是如何从 M个相关的板坯垛位中选择 N个板坯 ,在满足相应的轧制单元计划所需要的板坯序列要求的条件下 ,保证总的板坯倒垛次数最少 .首先对倒垛问题进行了定义 ,在分析了问题的邻域结构基础上 ,构造了新的多回路启发式算法 .通过精选的随机产生的 2 0 0个问题例子的实验显示 ,提出的启发算法的性能在计算速度和最优性方面都明显优于原系统的启发式算法 ,在最优性方面平均改进率达到 2 0 % ,在计算时间方面 ,可降低一半以上 .新的多回路启发式算法不但提高了车间作业率 ,也大大降低了生产过程控制机 (FL S)

The slab yard can be used to store slabs produced in steelmaking continuous casting process and required to further form strips and plates by the hot rolling mill. A slab yard can be divided into a large number of logic sections each including many pile locations. Slabs are stacked in the slab yard according to the pile location. The optimal turned out slab pile (TOSP) problem is to determine N slabs from M related pile locations so that the total turned out slab pile number can be minimized while the corresponding slab sequence requirements of the rolling turn are satisfied. This paper first gives the definition of the optimal TOSP problem. Then, a new multiple loop heuristic algorithm is constructed and implemented. The computational experiments with 200 selected problem instances produced randomly show that the new proposed heuristic algorithm performs remarkably better than the old one. The average optimality of the algorithm is enhanced by 20 % and the computation time is reduced by about 50 %. The new algorithm not only increases the shop floor productivity, but also cuts down greatly the workload of FLS.