| Automobile manufacturers are facing a fierce global competition.To improve the competitiveness of enterprises,the mixed-model manufacturing technology is adapted.It makes it possible to to produce a variety of different models,different quantities but basically similar products with the same production system or unit,without big change of the existing production conditions,with high flexibility.However,mixed-model manufacturing technology must meet higher requirements because of the more diversified product varieties and the more volatile product demand.Products manufactured with mixed-model assembly line of automobile manufacturing workshop are of multi varieties,frequently changed and with high fluctuation of quantities.In order to improve the workshop production efficiency and resource utilization rate,reduce the manufacturing cost and shorten the order completion time,the enterprises pay more and more attention to the continuous improvement of the assembly line and the production logistics in the automobile manufacturing workshop.It is difficult to meet the actual production needs for the traditional,manual improvement method depending on manufacturing experience.Automobile manufacturers urgently need scientific and efficient continuous improvement method for the actual mixed flow assembly line and production logistics.In this paper,the mixed-model production workshop of an automobile enterprise is taken as the research object,and the assembly line balancing problem and the workshop logistics optimization are studied with the intelligent optimization algorithm,in order to improve the efficiency and reduce the cost.(1)This paper summarizes the recent research situation of assembly line balancing problem and logistics optimization,and analyzes the characteristics and difficulties of mixed-flow workshop of automobile enterprises.Based on the research of the assembly line balancing problem,logistics layout problem and material storage location assignment problem,the paper puts forward the corresponding solution,and establishes the research objectives and methods.(2)In the study of the single-type two-sided assembly line balancing problem,the mathematical model of the problem is established.The "Multi-Neighborhood Path Relinking Algorithm"(MN-PR)is designed to solve the problem.The proposed MN-PR algorithm integrates a number of distinguishing features,such as a multi-neighborhood based local search procedure,a dedicated path relink operator to generate new solutions and a strategy to fix an infeasible solution generated by the path relink.Our proposed MN-PR algorithm is tested on a set of public instances widely used in the literature.Comparisons with other reference algorithms show the efficacy of the proposed algorithm in terms of the solution quality.For most cases,it can find the optimal or near optimal solution within a reasonable time.Particularly,the proposed MN-PR algorithm is able to improve the best upper bounds for one instance with 65 tasks and 326 cycle time.(3)Based on the math model of the single-type two-sided assembly line balancing problem,the math model of the mixed-model two-sided assembly lines problem is established,and the decoding method is improved.The MN-PR algorithm is used to solve the model and verified by a set of public instances.Furthermore,the mixed-model assembly line balancing problem of an actual engine sub-assembly line is studied.The objective function and the decoding method are modified for the practical problem.The MN-PR algorithm is used to solve the problem.The calculation result is reduced by two stations compared with the original layout.The station's work efficiency is generally improved,and more balanced.(4)This paper studies the storage location assignment problem of a mixed-flow workshop and two general mathematical models are proposed for different constraints.The MN-PR algorithm is improved by adding a new neighborhood to obtain better results.The storage location assignment problem of a mixed-flow workshop of a certain automobile enterprise is studied,it consists of two of the models mentioned before.A multi-stage MN-PR algorithm is designed and verified by the actual production data of the enterprise.The result satisfies the demand of the enterprise,because the production capacity is increased,and the workers utilization is more balanced.(5)This paper introduces the production logistics system and its operation flow of a mixed-flow automobile workshop,discusses some factors affecting the kitting efficiency,such as the rack layout,AGV walking route,material storage location assignment and picking path,and other various combination of them.By using program Plant Simulation,A total of four solutions are simulated including two actually used solutions and two new solutions proposed in this paper.The simulation model of automobile assembly line and kitting area(MV4)production logistics is established and the picking logic of different solutions are simulated.The simulation results of the original scheme of the enterprise are very close to the actual production situation.The simulation results of the two new schemes proposed in this paper are superior to the actual solutions,which have the advantages of reducing the cost and improving the efficiency,and providing theory and simulation data for the logistics decision.Finally,the paper summarizes the whole paper and points out the direction of further research. |
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