A New Class Of Analysis For Production And Logistics Scheduling

The iron and steel industry is one of the mainstay industries of the national economy. In recent years, along with the rapid development of China’s economic construction, there will be higher requirements for the quantity and quality of the steel. The production process of iron and steel industry is very complicated, the relation among the stages of production is compact, and the logistics with intersection and network structure. These features determine that there are requirements about the production schedule on the operations, the transportation schedule between the operations, and the coordination schedule of production and transportation. A reseasonable schedule for production and logistics can be propitious to raise the equipment utilization rate and management, and reduce the unnecessary waiting times. Accordingly, a reseasonable schedule can contribute to decrease the energy consumption and such that it may reduce the production and transportation cost, improve the quality of the products, and boosting steel industry competitiveness.Based on the actual production process of annealing and allocation planning of strip coils for ships in the iron and steel industry, From the two operations, we refine the production and transportation scheduling problems with machine capacity constraints, conversion costs, and three dimensional distribution. Adopting variety technology, such as complexity analysis, heuristic algorithms, worst-case performance ratio analysis, MILP, we investigate the problems from the following three aspects: scheduling problems with machine capacity constraints, the loading program of river steamship, the loading program of seagoing vessel. The content is summarized as follows.1) The scheduling with machine capacity constraints, conversion costs.Based on the actual production process of annealing in the iron and steel industry, according to actual requirements and constraints of annealing, this paper refines a new batch scheduling problem:when works are processed on parallel machine, The machine requires maintenance, and it brings setup cost and setup time. In addition, the transformation of the continuous processed coils causes the cost. The objective is minimizing the makespan and the total transformation cost. We build the mathematical linear programming model for it. We can prove the problem is strongly NP hard by induction. We propose a heuristic algorithm for solving this problem and analyze its worst case performance. Meanwhile, we propose a heuristic algorithm for the specific situations. Besides, we analyze its worst case performance and average case performance for the performance evaluation of the heuristic algorithm.2) The loading program of ships.This paper is based on allocation planning of strip coils for ships. We refine the logistics problem for strip coils. In the paper, we consider the coil weight constraint, coil width constraint and coil diameter constraint between the upper and lower layers, distance constraint, the balance constraint of the side of a ship, the balance constraint of the fore and aft, the port balance constraint and so on. The objective is to minimize the port balance punishment, the dispersion and the number of lifting. We need to consider the full-precision positions of the strip coils in the three-dimensional space. For the problem, we build river steamship mathematical linear programming model. According to the strip coils’regulations of the finished coils, we can load the coils safely and reasonably and make the objective function minimize. Finally, numerical simulations are carried out to verify the validity of the two models.In the end, on the base of the actual problem of transportations in the two processes of production and logistics, we refine transport coordination problem model for multiple machines and ships, constraint problem model for production and logistics coordination order, transport coordination problem model for capacity constraints and so on. We make an elementary analysis for the further study.