履带起重机装配线平衡研究及应用

发布时间：2018-03-07 11:51

本文选题：装配线平衡　切入点：遗传算法　出处：《上海交通大学》2012年硕士论文　论文类型：学位论文

【摘要】：履带起重机具有结构复杂、体积和重量庞大等特点，广泛采用定点装配的方式。但在定点装配过程中，会有装配效率低、配送复杂、待制品多等问题产生，随着市场竞争的加剧，，S公司为提高履带起重机的装配效率、缩短生产周期，提高产品竞争力，决定采用流水线装配。装配线平衡是规划高效装配线的重要问题之一。首先，结合履带起重机的构造，分析了履带起重机装配存在效率低、待制品过多，物流配送困难等问题。利用时间测量法测量各装配任务的作业时间，依据装配工艺建立了装配作业先序图，确定了装配线平衡目标。设计了履带起重机装配线平衡的遗传算法，包括编码、交叉算子、选择算子，变异算子和适应度函数等，优化装配任务的分配，得到工站数量及各作业内容在各工站的作业分配方案，并使平台、履带架及合车三条装配线的平衡率均超过90%。最后，考虑装配任务作业时间的随机波动，利用eM-Plant仿真软件建立了履带起重机的装配线仿真模型，并通过分析工位的负荷，确定瓶颈工位及潜在的瓶颈工位。提出基于邻域工位负荷差的装配任务调整规则对瓶颈工位进行改善，并对潜在的瓶颈工位进行机械化及自动化水平提升，进一步平衡工位负荷，确保装配线在作业时间随机波动情况下的可靠性。履带起重机装配线节拍为167min的情况下，年生产能力为1011台，可靠性达到97.12%；满足年产能900台和靠性95%的要求。有效解决了履带起重机的装配流水线平衡问题。
[Abstract]:Crawler crane has the characteristics of complex structure, huge volume and weight, and it is widely used in fixed-point assembly. However, in the process of fixed-point assembly, there will be problems such as low assembly efficiency, complicated distribution, and many products to be produced. In order to improve the assembly efficiency of crawler cranes, shorten the production cycle and improve the competitiveness of products, the company has decided to adopt pipeline to assemble the assembly line balance, which is one of the important problems in the planning of high-efficiency assembly line. First of all, combined with the construction of crawler crane, this paper analyzes the problems of low efficiency, too many products to be produced and difficulty of logistics distribution in assembly of crawler crane. The time measurement method is used to measure the working time of each assembly task. According to the assembly process, the first order diagram of assembly operation is established, and the balance target of assembly line is determined. The genetic algorithm of assembly line balance of crawler crane is designed, including coding, crossover operator, selection operator, mutation operator and fitness function, etc. The distribution of assembly tasks is optimized, and the distribution scheme of the number of stations and the contents of each operation in each station is obtained, and the balance rate of the three assembly lines of platform, track frame and vehicle is over 90%. Finally, considering the random fluctuation of assembly task time, the assembly line simulation model of crawler crane is established by using eM-Plant simulation software, and the load of work station is analyzed. The bottleneck station and the potential bottleneck station are determined. The assembly task adjustment rules based on the load difference of the neighborhood station are put forward to improve the bottleneck work station, and the mechanization and automation level of the potential bottleneck work station is improved. Further balancing the work load to ensure the reliability of assembly line under random fluctuation of working time. The annual production capacity of crawler crane assembly line is 1011 when the rhythm of assembly line is 167min. The reliability reaches 97.12 and meets the requirements of annual production capacity of 900 units and reliance of 95%. It effectively solves the balancing problem of pipeline for the assembly of crawler cranes.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH213.7

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