快速分拣线中自动补货系统的建模与优化

发布时间：2018-04-29 01:12

本文选题：自动补货 + M/G/1排队模型　；参考：《山东大学》2014年硕士论文

【摘要】：随着产业结构的调整,劳动力成本的上涨,物流系统自动化建设的步伐不断加快。2012年国内物流自动化分拣设备市场增长在20%以上。自动分拣系统具有分拣速度快、准确率高等特点,在医药、烟草、食品、汽车等行业应用尤为突出。自动补货系统保证了自动分拣系统的正常运行,是系统高效分拣的前提。但是目前对于自动补货系统的设计和改进,往往只停留在根据设备的性能按照经验参数进行配置的阶段。没有结合实际的分拣情况和品项分配等进行精确的定量分析,缺少准确的理论依据和衡量指标。因此,如何用定量的方法,衡量各个补货指标,对自动补货系统的设计和改进有十分重要的意义。本文应用排队系统理论对自动补货系统进行建模,得出了最大补货效率、平均补货周期、待执行的任务数三个补货指标与分拣效率、补货设备的速度、服务时间、品项分配等变量的数量关系,为系统的配置提供数值依据。同时,对数量关系进行分析,在成本不变的情况下,通过优化品项分配提高补货效率。本文对两种常用的补货模式分别进行了建模和仿真验证,并对备货系统在实际运作过程中因分拣线发生故障而引起的阻塞问题提供了解决方案。往复式补货模式的建模与优化：首先将补货命令到达的过程和补货服务时间利用卡方分布进行模型拟合,由于其分别近似服从Poisson分布和指数分布,因此将其抽象为M/G/1排队系统；结合实际的补货流程,根据分析出的两种具有实际意义的补货服务时间改进了的三个补货指标。其次以平均补货周期为目标,利用遗传算法进行品项分配优化；最后通过实例仿真,验证了模型的适用性和优化算法的有效性,优化后的补货效率提高了7.2%,并分析了最大补货效率、分拣效率与各个补货指标的关系。环形补货模式的建模与仿真：首先将其抽象为M/D/c排队系统,根据两种服务时间求出改进的三个补货指标；其次对模型进行实例仿真,结果表明该模型可以很好的计算出环形补货的运行参数,为优化自动补货系统提供了依据；最后对两种补货模式在占用空间、成本、效率、可扩展性等方面进行了对比和分析。本文最后通过设置最优的故障缓存长度解决了因某条分拣线发生故障而引起的补货阻塞问题,保证了其他分拣线的正常分拣；通过二分查找算法实现了故障缓存长度的求解；然后分析随着补货量、补货效率的变化而呈现的规律,综合考虑空间、设备成本、服务质量等指标,确定最优的故障缓存长度。实例仿真显示,比服务时间按照定长节约5%。
[Abstract]:With the adjustment of industrial structure, the rise of labor cost and the pace of automation of logistics system, the market of automatic sorting equipment of domestic logistics is increasing more than 20% in.2012 years. The automatic sorting system has the characteristics of fast sorting speed and high accuracy, especially in the fields of medicine, tobacco, food and automobile.
The automatic replenishment system ensures the normal operation of the automatic sorting system and is the precondition for the efficient sorting of the system. However, the design and improvement of the automatic replenishment system at present is usually only in the stage of configuration according to the performance of the equipment according to the experience parameters. The accurate quantitative analysis is not combined with the actual sorting and item allocation. Therefore, it is of great significance for the design and improvement of the automatic replenishment system to measure the index of each replenishment by quantitative method.
This paper uses the queuing system theory to model the automatic replenishment system, and obtains the maximum replenishment efficiency, the average replenishment cycle, the number relation of the number of replenishment indexes and sorting efficiency, the speed of the replenishment equipment, the time of the replenishment equipment, the service time and the distribution of items, so as to provide the numerical basis for the configuration of the system. In the case of the constant cost, the restocking efficiency is improved by optimizing the item allocation. This paper carries out modeling and simulation verification on two kinds of common replenishment modes, and provides a solution to the blocking problem caused by the failure of the sorting line during the actual operation of the stock system.
The modeling and optimization of reciprocating replenishment mode: first, the process of replenishment orders and the time of replenishment service are fitted by the chi square distribution. Because of their approximate obeying the Poisson distribution and exponential distribution, they are abstracted as M/G/1 queuing system, and two kinds of analysis are combined with actual replenishment flow. The meaning of the replenishment service time improved three replenishment indexes. Secondly, using the average replenishment cycle as the goal, the genetic algorithm is used to optimize the item allocation. Finally, the applicability of the model and the effectiveness of the optimization algorithm are verified by the example simulation. The efficiency of the replenishment is raised by 7.2% after the optimization, and the maximum replenishment efficiency and sorting efficiency are analyzed. The relationship between the rate and the replenishment index.
The modeling and Simulation of ring replenishment model: firstly, it is abstracted as M/D/c queuing system, and the improved three replenishment indexes are obtained according to two service times. Secondly, the model is simulated by example. The results show that the model can calculate the operating parameters of ring replenishment well, and provide the basis for optimizing the automatic replenishment system. Finally, the model is provided. The two replenishment models are compared and analyzed in terms of occupancy space, cost, efficiency and scalability.
At the end of this paper, the problem of replenishment congestion caused by the failure of a certain sorting line is solved by setting the optimal fault caching length, and the normal sorting of other sorting lines is guaranteed. The solution of the length of the fault caching is realized by the two point search algorithm, and then the regularity with the amount of replenishment and the change of the replenishment efficiency is analyzed. Considering the space, equipment cost, service quality and other indicators, the optimal fault caching length is determined. The example simulation shows that the service time is saved by fixed length 5%..

【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：O226;F259.23

【参考文献】