Multi-objective optimization for draft scheduling of hot strip mill

LI Wei-gang(李维刚)^{1, 2}, LIU Xiang-hua(刘相华)³, GUO Zhao-hui(郭朝晖)^{1, 2}

(1. College of Information Science and Engineering, Northeastern University, Shenyang 110819, China;
2. Automation Division of Research Institute, Baosteel Group Corporation, Shanghai 201900, China;
3. Research Institute of Science and Technology, Northeastern University, Shenyang 110819, China)

Abstract:A multi-objective optimization model for draft scheduling of hot strip mill was presented, rolling power minimizing, rolling force ratio distribution and good strip shape as the objective functions. A multi-objective differential evolution algorithm based on decomposition (MODE/D). The two-objective and three-objective optimization experiments were performed respectively to demonstrate the optimal solutions of trade-off. The simulation results show that MODE/D can obtain a good Pareto-optimal front, which suggests a series of alternative solutions to draft scheduling. The extreme Pareto solutions are found feasible and the centres of the Pareto fronts give a good compromise. The conflict exists between each two ones of three objectives. The final optimal solution is selected from the Pareto-optimal front by the importance of objectives, and it can achieve a better performance in all objective dimensions than the empirical solutions. Finally, the practical application cases confirm the feasibility of the multi-objective approach, and the optimal solutions can gain a better rolling stability than the empirical solutions, and strip flatness decreases from (0±163) IU to (0±45) IU in industrial production.

Key words:hot strip mill; draft scheduling; multi-objective optimization; multi-objective differential evolution algorithm based on decomposition (MODE/D); Pareto-optimal front