Shengping Yu

Complete Modification Rescheduling Method and Its Application for Steelmaking and Continuous Casting

Abstract Delayed processing time and machine failures upset the plan in steelmaking-continuous casting (SCC) production, which make production plan infeasible. The manual repairing cannot satisfy objectives of quick response and optimal scheduling. The practical rescheduling with 1-4 refining stages cannot abstract as three stages hybrid flow shop (HFS). A method is presented for the rescheduling problem, which includes two steps. Firstly, the assigning machine strategy and its computing algorithm are given. Secondly, the mathematical models are developed as multi-objective model based on practical production constraints, so as to solve machine conflicts. The dynamic scheduling system for SCC with the rescheduling method has been successfully applied to Shanghai Baoshan steel plant, and realizes rapidly optimal rescheduling.

Production planning simulating system for tire vulcanization based on heuristic algorithm

In the process of tire production, vulcanization process is the last process and core process in the total production. The vulcanization process becomes the main bottleneck of the whole tire production process because of the processs long manufacture time, manufacture centralizing, energy sources large consume. Its plan quality is the key function of improving the utilization of vulcanization equipments and reducing the production cost. Production planning simulating system for vulcanization process based on heuristic algorithm was developed on the basis of studying planning strategy. The system integrates production planning, adjusting production starting time, adjusting the number of devices, inserting orders and withdrawing orders. The software system was tested by online data. Results show that the planning method can quickly workout the optimal production planning of vulcanization. The method will lay the firm groundwork for application to production process in the future.

A two-stage heuristic method for vulcanization production scheduling

There are more product specifications, great production and much equipment over the whole process of rubber tire vulcanization. Aiming at rubber tire vulcanization production scheduling single-process, parallel machines scheduling problem with special process constraint, a two-stage scheduling strategy of vulcanization production, the load distribution of equipment and operation plans sequencing, is proposed. Equipment load distribution model of vulcanization machine based on 0–1 integer programming is built and improved maximum elimination algorithm is proposed. Operative plan sorting model based on 0–1 integer programming is built and an optimal algorithm based on minimum delay time is proposed. The algorithm was tested by online data. Results show that the two-stage scheduling method can quickly workout the optimal scheduling planning of vulcanization, reduce the production cost, and improve productivity. The method will lay the firm groundwork for application to production process in the future.

Cast Batch Planning for Steelmaking and Continuous Casting Based on Ant Colony Algorithm

A multi-objective 0-1 integer programming model is established in order to solve the complex problem of cast batch planning for steelmaking and continuous casting which is considered as vehicle routing problem. To solve the complex multi-constrained, multi-objective cast batch planning model for steelmaking and continuous casting, a method is proposed which combines rules with ant colony algorithm. The algorithm is tested by online data. Results show that the proposed algorithm can quickly workout the optimal cast batch planning for steelmaking and continuous casting, and can lay the firm groundwork for application to production process in the future.

Simulation system for logistics in steelmaking process based on Flexsim

Because of the complexity, dynamicity and uncertainty of the steelmaking process, it is difficult to establish the simulation model to express most characteristics of the mixed production system for mathematical method. This paper researches the steelmaking logistics model which includes production equipment and production process, and establishes the simulation system for logistics in steelmaking process based on Flexsim which includes the process simulation, human-computer interaction and decision-making. The simulation results have shown the efficiency of the simulation system by practical production data. The simulation system supplies the object experimental platform for the study of steelmaking scheduling methods which are suitable for practice.

Steelmaking-Casting of Molten Steel by Decarburization Ladle Matching

Steelmaking–continuous casting is a complex process. The method of selecting a ladle, which also functions as a storage device, follows a specific process of the production plan. In ladle matching, several ladle attributes are considered. However, matching objectives are difficult to achieve simultaneously. Different molten steel properties have contributed to the complexity of matching constraints, and, thus, matching optimization is regarded a multiconflict goal problem. In the process of optimization, the first-order rule learning method is first used to extract key ladle attributes (performance indicators), including highest temperature, usage frequency, lowest-level material, and outlet. On the basis of a number of indicators, such as ladle temperature, quantity, material, and usage frequency, as well as skateboard quantity, the ladle matching model is established. Second, the rule of ladle selection is determined by the method of least-generalization rule learning. Third, a simulation experiment is carried out according to various scheduling order strategies and matching priority combinations. Finally, the heuristic ladle matching method based on the rule priority (RP) is determined for possible industrial applications. Results show that the accuracy of ladle selection can be improved. In particular, the numbers of ladles and maintenance times are reduced. Consequently, furnace production efficiency is also enhanced.

Dynamic scheduling system for steelmaking-refining-continuous casting production

Because of different refining route of every charge, its difficult to make a static scheduling plan for steelmaking-refining-continuous casting (SRCC) production. There are many types of disturbances that upset the scheduling plan including processing time variation, temperature variation, quality variation, flow speed variation of cater, machine failures, and which could cause the static scheduling to become inefficient and even infeasible. It is necessary to adjust the schedule or generate a new executable schedule upon the occurrence of unanticipated disruptions and changes. An optimization scheduling strategy framework is proposed including static scheduling, dynamic scheduling, assistant equipment scheduling. The static scheduling plan is made by using expert systems, programming method, fuzzy evaluation. The dynamic scheduling is including the partial rescheduling and complete rescheduling by using heuristic and programming methods. The assistant equipment scheduling plan is made based on heuristic method. The dynamic intelligent scheduling system was developed with the optimization scheduling strategy, and has been applied to a large steel enterprise steelmaking-refining-continuous casting production.

Intelligent Rescheduling System for Steelmaking and Continuous Casting Production

There are many types of disturbances that upset the plan in steelmaking and continuous casting (SCC) production, including processing time variation, temperature variation, quality variation, machine failures, which could cause the static schedule to become inefficient and even infeasible. It is necessary to adjust the schedule or generate a new executable schedule upon the occurrence of unanticipated disruptions and changes. Two rescheduling methods are presented: the partial rescheduling and complete rescheduling. The former refers to the right shift partial rescheduling based on continuous casting, the partial rescheduling based on case-based reasoning and man-computer interaction. The latter refers to the complete rescheduling considering changeable processing time, the complete rescheduling considering changeable processing time and production path. The mathematical models of two class complete rescheduling are formulated, and the solving methods are also given. The intelligent rescheduling system for SCC production with these methods is successfully applied to one large steel plant, and rapidly optimal rescheduling is achieved when disturbances occur.

Scheduling method for tire building based on heuristic algorithm

There are more product specifications, great production and much equipment over the whole process of tire building. The actual complex scheduling problem of tire building is described in detail. To solve the complex multi-objective, large-scale production scheduling problem of tire building, a heuristic algorithm is proposed from the experience of the experts. The algorithm was tested by online data. Results show that the heuristic algorithm can quickly workout the optimal production scheduling of tire building, reduce the production cost, and improve productivity. The algorithm will lay the firm groundwork for application to production process in the future.

Dynamic Optimal Scheduling Method and Its Application for Converter Fault in Steelmaking and Continuous Casting Production Process

In steelmaking and continuous casting (SMCC) production process, converter fault can lead to unexpected changes to the pre-specified converter-continuous caster production mode so that the original scheduling plan becomes unrealizable. In this paper, the dynamic scheduling problem in response to converter fault is firstly analyzed. This is then followed by the establishment of a novel multi-objective nonlinear programming model (MONPM) by introducing the production mode parameter I±, production schedule parameter I² and I�. The proposed method considers changes in production mode, production schedule of charge, the interval characteristics of processing time. In specific, a two-stage dynamic optimal scheduling method is proposed including the production path planning of charges (PPP) and the production time scheduling (PTS). As a result, a dynamic optimal scheduling software system (DOSSS) is developed and is successfully applied to the scheduling of the largest iron and steel company (BaoSteel) in China. The real-time application shows that the proposed method can efficiently reduce scheduling time, significantly increase the outputs of converters and dramatically shorten the redundant waiting time for molten steel.