Study On Modeling And Optimization Method For Crane Scheduling In Casting Workshop

For the manufacture enterprises,as an important part of CIMS(Computer Integrated Manufacturing System),production scheduling is the key technology of production operation control and production management.And it is of great significance to optimizing the allocation of resources,reducing production costs,improving production efficiency and the competitiveness of enterprises.Crane scheduling is an important part of production scheduling,which lays a foundation for the implement of production scheduling scheme,the logistics connection among processes smoothly and the production operating safely and stably.Differ from the crane scheduling in general manufacturing shop,the crane scheduling in casting workshop of steel plant is more difficult to solve due to the characteristics of multi-machines multi-tasks,spatio-temporal constraints and crane collisions.This paper aims at exploring an effective solving algorithm for crane scheduling problem in casting workshop of steel plant,which can provide guidance for the actual production process,and offer reference for crane scheduling in general manufacturing shop.The research work aimed at the casting workshop of steel plant,firstly the elements of crane scheduling system were analyzed,then a simulation model was established to solve a feasible crane scheduling scheme.Furthermore a mathematical model was built to describe the problem,and a hybrid method of integrating simulation model and genetic algorithm was designed to solve this model.At last some experiments were conducted by using the production data in the casting span of a steel plant.A feasible and optimized crane scheduling scheme was obtained.The main work are as follows:(1)The elements of crane scheduling system include transportation tasks,cranes and workstation.The basic thought of this paper to solve a feasible crane scheduling scheme includes the matching rule which is designed for choosing crane according to the relationship between the position of crane and the transportation task in the crane selection process,the updating rule which is designed for describing the evolution of state and position of cranes in the running process,the priority rule of transportation task which is designed for choosing collision avoidance crane according to the category and estimated transportation time of task in the collision resolution process.(2)A mathematical programming model was built to minimize the total waitingtime of tasks,the total transportation time of tasks and the difference among the transportation time of cranes by considering full ladles,empty ladles and assistant tasks as transportation tasks.And then a hybrid method of integrating simulation model and genetic algorithm was formulated : the crane sequence was designed as chromosome coding,and the crane scheduling schemes includes crane sequence and crane running process were generated through running simulation model.And then these crane sequences were evolved optimized through genetic algorithm.These new crane scheduling schemes could be generated through running simulation model based on these new species.Therefore,more excellent individuals will be produced along with the evolutionary process.Thus a better crane scheduling scheme could be obtained finally.(3)To validate the hybrid method,the slab continuous casting span in Panzhihua Iron and Steel was taken as application background.Firstly,the transportation tasks in 4hours were taken as raw data,and the crane scheduling scheme obtained by using simulation model was compared with the scheme obtained by using hybrid method,the feasibility and efficiency of hybrid method was verified.Then the type of predicting the assist task before formulating crane scheduling scheme was compared with the type of carrying out the formulated crane scheduling scheme,the result show that the hybrid method could be used in dealing with the emergency.At last the tabu search algorithm was designed to comparing with the hybrid method,through taking the tasks of five different scale as the input data,the efficiency of hybrid method was verified further.The research shows that: The hybrid method of integrating simulation model and genetic algorithm could be used to formulate the reasonable and optimized crane scheduling scheme.The crane scheduling model and the solving method designed in this paper could provide guidance for the actual production process in steel plant and offer reference for crane scheduling in general manufacturing enterprise.