مدل سازی و شبیه سازی سیستم های تولید انعطاف پذیر شی گرا: یک روش مبتنی بر قواعد

Simulation by a software model, is one of the most frequently used techniques for the analysis and design of manufacturing systems. In the software engineering research area, the object-oriented approach has fully demonstrated to be an effective technique with respect to the design and implementation phases of complex software projects. Even if object-oriented programming has proven to be a powerful technique, a systematic design method should also be used in order to implement reliable software, in particular in the development of simulation models. This paper presents a new procedure to develop flexible manufacturing system (FMS) simulation models, based on the UML analysis/design tools and on the ARENA® simulation language. The two main features of the proposed procedure are the definition of a systematic conceptual procedure to design FMS simulation models and of a set of rules for the conceptual model translation in a simulation language. The goal is to improve the software development efficiency through a rule-based approach and to add some of the fundamental object-oriented features to the ARENA® simulation environment.

A flexible manufacturing system (FMS) is an integrated production system composed by a set of independent machining centers (MCs). An automatic part handling system (PHS) interconnects the MCs to a group of part-storage locations such as loading/unloading positions and input/output buffers. An automatic tool handling system (THS) interconnects the MCs to a group of tool-storage locations as tool magazines, tool rooms, exchangers and spindles [10] and [16]. Either the PHS and THS mechanisms consist of one or more automated guided vehicles (AGVs) or transporters. A central supervisor (the FMS control software) monitors and manages the whole system. Three different kinds of object flows may be identified: the material flows (physical objects as parts, tools, pallets and fixtures), the information flows (abstract objects that describe the system status), and the decision flows (abstract objects that modify the system status) [12] and [22]. The FMSs are complex and expansive systems that require an accurate designing phase. In particular, it is important to examine closely the dynamic behavior of the different FMS components in order to predict the performance of the production system. The simulation is an essential tool for the design and the operational performance analysis of complex systems that cannot be easily described by analytical or mathematical models [19]. In particular, in the manufacturing field, the simulation can be used to configure the production system, or to select the more appropriate management rules [17].

In the field of FMS simulation, a need exists to develop a modeling procedure in which an object-oriented design phase is integrated to an implementation phase that is made with a common transaction-oriented simulation language [12]. In this paper, a new procedure to develop FMS simulator software (UMSIS) is presented. The object is to formulate a new procedure for developing reusable, modifiable and extendible discrete-event simulation-software using an object-oriented approach implemented in a transaction-oriented language. The work involved here includes the use of UML for specifying the system’s requirements, a set of concepts to model FMSs, and a procedure that can be used to automate the construction of ARENA® programs from UML specifications. The proposed procedure aims responding to the need of simulation developer by identifying the objectives of the model development and by guiding the modeler in the execution of the process to achieve those objectives. UMSIS includes methods, techniques to accomplish individual tasks, and it prescribes an order in which each task is made.