Research On Scheduling Method Of Main And Accessorial Equipment For Steelmaking-Continuous Casting Production Under Lagrange Framework

Steelmaking-continuous casting production link is the bottleneck of the steel production process.With the improvement of the international competitiveness of the iron and steel industry,the demands of steelmaking-continuous casting production for the time dynamic balance adjustment of main equipment and the collaborative operation function of accessorial equipment are constantly increasing.The main and accessorial equipment for steelmakingcontinuous casting production scheduling can improve the utilization of main and accessorial equipment,reduce redundant waiting time between processes,reduce production costs,reduce energy consumption,and then to achieve the purpose of improving production efficiency and product quality,and shortening the product production cycle.Therefore,scientific and effective main and accessorial equipment for steelmaking-continuous casting production scheduling plays a vital role in the production of iron and steel enterprises.In the main and accessorial equipment for steelmaking-continuous casting production scheduling,not only the multiple performance indexes of the production process should be satisfied,but also the operation conflicts and operation constraints of main and accessorial equipment should be considered,which makes the scheduling problem difficult to be accurately described by mathematical model.At the same time,in the process of solving large-scale main and accessorial equipment for steelmaking-continuous casting production scheduling,the existing methods have difficulties such as large storage space and slow calculation time,which leads to the complexity of the solution process and makes it difficult to obtain the global approximate optimization feasible solution in a short time in the actual production scheduling.In view of the above difficulties,based on the National Natural Science Foundation of China “Research on Integrated Optimization Method of Steelmaking-Continuous Casting Batch Planning and Production Scheduling under Uncertain Environment”(61873174),research on scheduling method of main and accessorial equipment for steelmaking-continuous casting production under Lagrange framework is studied,the main content includes as follows:Firstly,through the analysis and description of main and accessorial equipment for steelmaking-continuous casting production scheduling,based on the three main stages of traditional steelmaking,refining and continuous casting,the accessorial equipment(crane and trolley)is considered in the process production stage,the overall main and accessorial equipment production process stage is defined.The performance indexes of “continuous casting uninterruption”,“the sum of waiting time of all charges in the main and accessorial equipment processes”,and “the sum of the difference between the ideal start casting time and the actual start casting time of all casts on the caster” are used as the optimization goal,the constraints such as main and accessorial equipment machine capacity,continuous casting,and safety distance of accessorial equipment are comprehensively considered,and a mixed integer programming model of the main and accessorial equipment for steelmaking-continuous casting production scheduling is established.Secondly,the surrogate absolute value Lagrange relaxation algorithm is proposed to solve the main and accessorial equipment for steelmaking-continuous casting production scheduling problem,the multiplier is introduced to relax the coupling constraints of “continuous casting uninterruption” and “main and accessorial equipment machine capacity constraints” in the optimization problem,and the absolute value penalty item is added to punish the violating behavior of the constraint.The algorithm can reduce the oscillation of the traditional Lagrangian multiplier and improve the convergence speed while ensuring the solution quality.Based on the separable structure of the mixed integer programming model of the main and accessorial equipment for steelmaking-continuous casting production scheduling,the subproblem in unit of charge is obtained,and the lower bound of the original scheduling problem is obtained through the backward dynamic programming solution strategy,and the feasible solution is constructed by heuristic algorithm.Finally,based on the production data of a large domestic iron and steel enterprise,the MATLAB simulation platform was used to carry out experimental simulation test.Experimental tests of different scales show that the proposed model and algorithm guarantee the feasible solution quality and solution efficiency of the main and Accessorial equipment for steelmaking-continuous casting production scheduling problem and prove the effectiveness of the proposed method.