A decomposition-based hierarchical optimization algorithm for hot rolling batch scheduling problem

Abstract

In this paper, the hot rolling batch scheduling problem is formulated as a multi-objective vehicle routing problem with double time windows model, in which the first time window deals with the surface grade constraint and the second one is for the linkage modes. In view of the complexity of the proposed model and the priority of considered objectives in practical production, a decomposition-based hierarchical optimization algorithm is proposed to solve the model. Firstly, the model is decomposed into two sub-problems: vehicle routing problem with time windows (VRPTW) and single vehicle routing problem with time windows (SVRPTW). Secondly, MACS-VRPTW is used to optimize the VRPTW sub-problem, in which the first objective is prior to the second one. Then, dynamic programming and genetic algorithm are used to optimize the SVRPTW sub-problem so as to reach a higher hot charge temperature. Experimental results based on the practical production instances have indicated that the proposed model and algorithm are effective and efficient.

A GRASP heuristic for the hot strip mill scheduling problem under consideration of energy consumption

“…The second literature branch assumes instead that the order portfolio is exogenously given (Chen X et al 1998;Kosiba et al 1992;Ning and Wang 2006;Tang et al 2000;Xiong and Qidi 2002). Further, the issue of virtual orders is rarely addressed so far (Jia et al 2012;Wang and Tang 2008;Zhao et al 2009). …”

“…To this end the penalty costs evaluate jumps in width as well as rolling thickness, hardness or rolling temperature between adjacent orders. Thus, they address the width profile as well as the adjacent order characteristics (Chen X et al 1998;Chen Y et al 2012;Jia et al 2012;Kosiba et al 1992;Liu 2010;Lopez et al 1998;Ning and Wang 2006;Tang et al 2000;Tu et al 2011;Wang and Tang 2008;Xiong and Qidi 2002;Yadollahpour et al 2009;Zhao et al 2009). …”

“…Thus, sequence dependent time line modelling is missing. Jia et al (2012) purpose to maximize the charging temperature level of slabs processed in hot charge rolling mode. To that end the slab age of those slabs is minimized.…”

“…Second, relating to the order portfolio, two literature branches can be distinguished with respect to the selection of orders: The first assumes that the portfolio of orders to be scheduled has to be selected initially from a set of available orders (Chen Y et al 2012;Jia et al 2012;Liu 2010;Lopez et al 1998;Tu et al 2011;Wang and Tang 2008;Yadollahpour et al 2009;Zhao et al 2009). The second literature branch assumes instead that the order portfolio is exogenously given (Chen X et al 1998;Kosiba et al 1992;Ning and Wang 2006;Tang et al 2000;Xiong and Qidi 2002).…”

“…The idea behind the minimization of the rolling turn number is to minimize setup costs (Jia et al 2012;Liu 2010;Tu et al 2011;Wang and Tang 2008;Yadollahpour et al 2009;Zhao et al 2009). The background of penalty cost minimization is to maximize quality and/or to minimize equipment wear.…”