Performance Analysis Of Shuttle-based Storage And Retrieval System With Different Input/Output Point

Shuttle-based storage and retrieval system(SBS/RS),as a new type of warehousing system with vertical and horizontal movement separated,has a wide range of applications in the new retail environment.Because the system has a horizontal shuttle on each tier,at a higher utilization rate of the horizontal shuttle,the elevator lifting table in vertical direction becomes the bottleneck of the system and affects the performance of the system.So analyzing the system performance changes of SBS / RS under different number and location of input/output(I/O)points is of great significance for the design and utilization of this system.This thesis mainly studied the influence of the number and location of input/output(I/O)points on the performance of the entire system.Based on the exciting studies and considering the real operating characteristics of transportation equipment,such as acceleration and deceleration,this thesis established the model of the expected travel time under single and dual commands,respectively analyzing the influence of two cases on the efficiency and throughput capacity of the system.The first case was when the I/O point lay in the midpoint of system's left side and the second case was when there were two I/O points functioning.As compared with the existing model with single I/O point appearing in the lower left corner of the rack,we found through computation that the expected cycle time of both the single and dual-command was greatly improved when the system I/O point was located at the midpoint of the left side of rack under the configuration of the single I/O point,for the average expected travel time was improved by 31.55% and the average capacity was improved by 46.12%.As compared with single I/O point,dual I/O points' average expected travel time of the vertical elevator lifting table was improved by 25.9%,and the capacity was improved by 38.13%.