Applying relational database to simulate the reconfigurable manufacturing system

Abstract

The operation of reconfigurable manufacturing systems (RMS) involves frequent changes in the structure and properties of different sales items, which implies the need to store and use a large amount of data. In this paper, we present an original solution to manage this problem. Storing the data of a RPD3D Petri network that models a RMS (and concerning its components, the relations between them, commands concerning different products and related operations, the information about RMS resources) can be done through a MySQL database. The transfer of the mentioned data and of the schedules concerning the expert numerical system entitled SODRMS (System for Optimal Driving the RMS) and having the architecture of a web portal implemented in Java with Java3Dgraphical elements, can be also realized by using the same MySQL database. SODRMS addresses to managers, which have to evaluate the received orders in terms of performance and to control the entire manufacturing process, from client order up to products delivery. The data regarding each order (product) can be recorded from the database in a SQL-type file and reloaded when needed (e.g. if intending to replay the simulation of fulfilling that order, with modified input parameters). Another application for such a database refers to the use of the compacting algorithm applicable to RPD3D Petri networks. This is necessary because they deal with high amounts of data and it enables to reach a compact visualization of these networks having large dimensions, by giving a new perspective on the simulation of a RMS functioning. The use of MySQL database for optimal controlling RMS-s has also the advantage of enabling the diversification of characteristics concerning the constitutive elements of the RPD3D Petri networks, by specific means.