A Basic Study on a Highly Distributed Simulation of Manufacturing Systems Under the Ubiquitous Environment

Abstract

This study reports a new simulation paradigm devised to simulate manufacturing systems in its real operational stage. The objective manufacturing system is supposed to be under ubiquitous environment; in other words, all machines and equipments constituting a real manufacturing system are all equipped with intelligent devices and are connected to an information network. In the framework of the proposed simulation method, the simulation model is not built on one computer as is done in the conventional simulation, but is built on the network by integrating the intelligent devices. Each devise with properly embedded simulation functions plays as a simulation agent representing a resource or an entity in the conventional simulation model. This paper discusses the simulation functions required to each device to form a discrete event simulation system. The time management of the simulation and the event processes in the new simulation paradigm are described.

A Distributed Production Scheduling Method for Highly-Distributed Manufacturing Systems

“…In the new discrete event simulation paradigm for HDMSs [7], the following simple algorithm was proposed for sorting events to be simulated in each simulation model implemented on each facility. Let assume that there are N computerized facilities (agents) each of which has its own simulation model.…”

“…This point has been discussed in the field of manufacturing simulation, and a new discrete event simulation paradigm for HDMSs was proposed [7]. In this paradigm, events, each of which is simulated in one of the facilities, are sorted by their occurrence time and this sorting is performed by exchanging messages about the occurrence times among the facilities.…”

A Method of Flexible Job-Shop Scheduling for Highly-Distributed Manufacturing Systems

“…Machine selection was performed by the PT rule [17] by which highest priority is given to the MC with the highest performance. The distributed FJS method was developed by applying the sequencing algorithm proposed for DDES for HDMSs [13] to driving occurrence of events and performing machine selection based on the PT rule. Figure 2 shows an example of priority sequencing of 4 agents.…”

“…DDES has a potential for being used in the operational stage, since it is not necessary to construct a model of the whole manufacturing system. Based on this expectation, a simple algorithm for priority sequencing concerning to events in the set of sub-models by communication among facilities has been developed [13]. This concept and algorithm can be applied to production scheduling based on simulation by dispatching rules, and distributed methods for flexible flow-shop scheduling [14], job-shop scheduling [15] and flexible job-shop scheduling (FJS) [16] were proposed.…”

Basic study on production scheduling method for highly-distributed manufacturing systems

“…This point has been discussed in the field of manufacturing simulation, and a new discrete event simulation paradigm was proposed (Fujii, et al, 2012). In this paradigm, events, each of which is simulated in one of the facilities, are sorted by their occurrence time and then the first event is simulated by the facility which the event belongs to.…”