روش مدل سازی جدید هیبریدی پویا برای برنامه ریزی عملیات

Today's highly competitive market places a great emphasis on improving efficiency and reducing costs. Simulation modelling is being widely used as a successful tool to design and analyze manufacturing systems. Enhancing the product design is an important issue. In addition, generating efficient simulation models with shorter lead times has become equally important to winning customer satisfaction. To meet these criteria, a new hybrid modelling approach for generating a simulation model and virtual environment from a process plan is presented. The proposed approach integrates simulation and virtual reality in order to render a dynamic shop floor model automatically using the basic process configurations. This is accomplished using an input database. The model interface is user-friendly so that the new users of simulation and administration can use the model easily once the input database requirement is fulfilled. Moreover, the model allows the user to trace the performance criteria of any process on the shop floor level at any instant as well as to experiment any production scenario. The virtual environment is used to verify through visualization the simulation model and also to provide a better understanding of the activities of the shop floor.

Simulation modelling is being widely used in areas, such as manufacturing, health, network communications, training, education, and military. Such popularity of simulation has resulted in a large number of simulation software tools available on the market [1], some of them are general-purpose simulators and some are designed specifically to model and analyze manufacturing systems. Manufacturing simulation has been one of the primary application areas of simulation technology. It has been widely used to improve and validate the designs of a wide range of manufacturing systems [2]. Virtual reality (VR) may play very significant rule to support the simulation tools to understand the results and the dynamic behaviour of the model [3]. Virtual reality offers the opportunity to visualize, explore, manipulate, and interact with objects within a computer generated environment, and is a useful tool to enhance process planning involved in design, development, evaluation, and validation [4]. Layout planning is not a new problem in the manufacturing environment. Virtual factories help in evaluating plant layout before actually building them and it assists in avoiding the costs involved in doing a physical re-layout. It also allows the user to get a better perspective than what could be achieved in 2D solutions [5]. Lee et al. [6] have presented the techniques, which are used in applying virtual reality in manufacturing applications. The problem with the simulation packages available on the market today, it requires good knowledge about programming and modelling techniques. Also, it is very time and money consuming to develop a simulation model for a manufacturing system [1]. This paper is devoted to the development of software with Graphic User Interface (GUI) using Visual Basic programming language that provides non-expert users with a flexible tool to develop simulation model dynamically of real shop floor activities. Virtual environment of the shop floor is generated automatically based on the input data, which is given by the user. The Graphic User Interface has three main options, which include input, process, and output. The input options are used to construct the process model of the manufacturing system that generates the process plan of the shop floor. The process options are used to generate the simulation model of the shop floor as well as the virtual model. The process options are also used to run the simulation model. Finally, the output option is used to display the statistics of the shop floor.

Simulation is a key technology to support manufacturing in the 21st century, and no other technology offers more potential than simulation and modelling for improving products, perfecting processes, reducing design-to-manufacturing cycle time, and reducing product realization costs [9]. 9VR is becoming an important method to solve engineering problems because of its special simulation features, such as immersion, real-time interaction, and 3D graphics. Its further application will not only depend on the development of VR technology, but more on its capability to provide cost effective solutions to real industrial problems [4]. This paper has discussed the development of software that integrates simulation and virtual reality technology to allow non-expert users to build simulation model and virtual model automatically through Graphic User Interface. The developed software has been tested with a real case study to build simulation model and virtual model of shop floor that consists of a number of Ovens, which does treatments operations. The software is developed to be user-friendly that allows users who does not have good knowledge about simulation modelling techniques and programming to develop dynamically simulation model of a manufacturing system and create virtual environment to simulate the activities of the manufacturing system in three-dimensional presentation in real time. The developed software can be used as tool to use some of the capabilities of Witness simulation software without a need to learn the modelling techniques of this software.