Academic literature on the topic 'Simulation for manufacturing systems'

Manufacturing is the largest single contributor to the global economy. The evolution of consumer demands has pressurised companies into producing a larger variety of products, with improved specifications, reduced costs, and shorter lead times. In this context, companies have found simulation techniques useful in their manufacturing systems design processes; simulation based on Discrete Event Simulation (DES) is the preferred technique. The complexity of manufacturing systems, and the mechanisms of DES, means that the simulation task often consumes excessive time and resources, such as data, software, and training. Evidence suggests that an alternative modelling technique, named System Dynamics (SD), is also appropriate for conducting this task. SD has been applied successfully in other fields, where its graphical notation is considered beneficial. However, the lack of an SD tool that is tailored toward manufacturing systems has prevented industry from adopting this technique more extensively. This thesis determines the extent to which SD can provide a credible alternative to DES in the manufacturing system design process. Information concerning DES, SD and practitioners' needs was gathered from published literature and from an interview survey. A functional prototype of a tool based on the SD principles, but tailored to model manufacturing systems was then developed. Three case studies then provided valuable information concerning the requirements of industry and the capabilities of the SD technique. This research programme has found SD to be sufficiently accurate and quicker than DES tools under certain conditions, requiring less data and skills. In addition, the user interface appears to have had a significant impact on the lack of adoption of SD techniques within the manufacturing sector. Simp1ifications made by this technique can reduce both model building and model execution time, and thus, experimentation time. However, evidence suggests that DES is still more prevalent, and that further work is required to develop SD based tools tailored to manufacturing systems. Therefore, this thesis provides a much improved understanding of the capabilities of SD as an aid to manufacturing systems design.

This dissertation research explores a reconfigurable hardware-based parallel simulation mechanism that can dramatically improve the speed of simulating the operations of flexible manufacturing systems (FMS). Here reconfigurable hardware-based simulation refers to running simulation on a reconfigurable hardware platform, realized by Field Programmable Gate Array (FPGA). The hardware model, also called simulator, is specifically designed for mimicking a small desktop FMS. It is composed of several micro-emulators, which are capable of mimicking operations of equipment in FMS, such as machine centers, transporters, and load/unload stations. To design possible architectures for the simulator, a mapping technology is applied using the physical layout information of an FMS. Under such a mapping method, the simulation model is decomposed into a cluster of micro emulators on the board where each machine center is represented by one micro emulator. To exploit the advantage of massive parallelism, a kind of star network architecture is proposed, with the robot sitting at the center. As a pilot effort, a prototype simulator has been successfully built. A new simulation modeling technology named synchronous real-time simulation (SRS) is proposed. Instead of running conventional programs on a microprocessor, this new technology adopts several concepts from electronic area, such as using electronic signals to mimic the behavior of entities and using specifically designed circuits to mimic system resources. Besides, a time-scaling simulation method is employed. The method uses an on-board global clock to synchronize all activities performed on different emulators, and by this way tremendous overhead on synchronization can be avoided. Experiments on the prototype simulator demonstrate the validity of the new modeling technology, and also show that tremendous speedup compared to conventional software-based simulation methods can be achieved.<br>Ph. D.

The use of simulation has been said to be a useful tool to analyze manufacturing systems, Discrete Event Simulation - DES for instance under the occurrence of different events. Information management in Manufacturing Systems is an important issue and so it is insimulation studies because some of the difficulties in building, reusing and integratingsimulation models with other applications used in manufacturing systems are related withthe data. In this context different efforts have been made to facilitate the use of simulationand overcome interoperability problems through improving the information management,one of this is the Core Manufacturing Simulation Data Information Model - CMSDIMdeveloped by The National Institute of Standards and Technology - NIST. The objective of this thesis is to contribute to the use of the CMSDIM in ExtendSim V8. A method to import databases structured based on the CMSDIM into the Simulation softwareExtendSim V8 is developed and applied in a case study in a production line of SCANIA.

This research explores a hardware-based parallel simulation mechanism that can dramatically improve the speed of simulating flexible manufacturing systems (FMS) by applying appropriate enabling hardware technologies. The hardware-based parallel simulation refers to running a simulation on a multi-microprocessor integrated circuit board, called the simulator, which is specifically designed for the purpose of simulating a specific FMS. The board is composed of a collection of micro-emulators capable of mimicking the operation of equipment in FMS such as machining centers, transporters, and load/unload stations. To design possible architectures for the board, a mapping technology is applied by making use of the physical layout information of an FMS. Under such a mapping method, the simulation model is decomposed into a cluster of micro emulator on the board where each workstation is represented by one micro emulator. Three potential architectures for the proposed simulator, namely, the bus-based architecture, the shared-memory based architecture, and the parallel I/O port based architecture, are studied. To provide a suitable parallel computing platform, a prototype simulator based on the combination of the shared-memory and the parallel I/O port architecture is physically built. Besides the development of the hardware simulator, a time scaling simulation method is also developed for execution on the proposed simulator. The method uses the on-board digital clock to synchronize the parallel simulation being performed on different microprocessors. The advantage of the time scaling technology is that the sequence of simulation events is sorted naturally in consistent with the real events. In this way, no entangled waiting is needed as in the conservative parallel simulation methods so as to reduce the synchronization overhead and the danger of having deadlock. Experiments on the prototype simulator show that the time scaling simulation method, combined with the unique hardware features of the FMS specific simulator, achieves a large speedup compared to conventional software-based simulation methods.<br>Ph. D.

Thesis (Ph. D.)--School of Computing and Engineering and Dept. of Mathematics. University of Missouri--Kansas City, 2005.<br>"A dissertation in engineering and mathematics." Advisor: Ghulam Chaudhry. Typescript. Vita. Title from "catalog record" of the print edition Description based on contents viewed June 26, 2006. Includes bibliographical references (leaves 341-346 ). Online version of the print edition.