A simulation study of multiple-load-carrying automated guided vehicles in a flexible manufacturing system

Abstract

Although the technology exists for more advanced applications of automated guided vehicles in flexible manufacturing systems, the current employment of these vehicles in material handling generally subscribes to a simple mode of operation: single-load-carrying capacity for each vehicle and unidirectional traffic on each route of the system. Through a simulation programme, this study investigates the.effect of several key factors related to the automated guided vehicles on the overall performance of a flexible manufacturing system. These are the number of pallets allowed in the system, the number of vehicles used and the carrying capacity of each and the input and output queue capacities of the machining stations; finally bidirectional traffic is allowed in some routes. The results show that there is a strong interaction among these factors and reveal their combined effects on the throughput from a small flexible manufacturing system. Upon the user's request, the simulation program also provides the animated colour graphics of the system to view developments concurrently under the selected decision values through time.

FMS performance under balancing machine workload and minimizing part movement rules

“…Machine-tools are assumed to work without breakdowns. The manufacturing environment to be studied is consistent with respect to the hardware specifications and operational parameters [12,13,21,25,28]. This study addresses the research hypotheses listed in Table IV.…”

“…The input variables for this study and their associated distributions and parameters are presented in Table III and have been found in previous studies [11-13; 23-24]. Using a uniform distribution for parts inter-arrival with mean of 2.857 minutes, this research seeks 70 per cent average machine utilization over the simulation horizon, midway within the range from 52 to 88 per cent reported in the literature [12,13,25]. Time to load or unload an AGV is short as a result of automation.…”

“…Run lengths of the same magnitude or less were used in previous flexible manufacturing simulation studies [12,13,19,20,37]. The inter-arrival distribution generates a mean of 21 parts per hour, therefore it is estimated that approximately 3,500 parts enter the system over the one week time span.…”

An adaptive SVM-based real-time scheduling mechanism and simulation for multiple-load carriers in automobile assembly lines

“…Researches showed that aside from the increase of system throughput and decrease of operation costs, there are many advantages to use multiple-load carriers, such as smaller fleet size, better device utilization, less traffic congestions, etc. [33][34][35] However, the scheduling problem of multiple-load carriers is much more complicated than these of single-load ones. For a singleload carrier system, only one load needs to be handled at each time.…”

Flexible manufacturing systems modelling and performance evaluation using AutoMod

“…A heuristic was used and minimized the times by exploiting the critical path of an integrated operation network [8]. Ozden used simulation to investigate the effect of AGV design factors on the throughput and machine utilizations of an FMS [9]. Rajotia et al proposed a heuristic methodology for configuring a mixed (hybrid) uni/bi-directional flow path for an AGV material handling system.…”