Design and discrete event simulation of power and free handling systems

Effective manufacturing systems design and implementation has become increasingly critical, with the reduction in manufacturing product lead times, and the subsequent influence on engineering projects. Tools and methodologies that can assist the design team must be both manageable and efficient to be successful. Modelling, using analytical and mathematical models, or using computer assisted simulations, are used to accomplish design objectives. This thesis will review the use of analytical and discrete event computer simulation models, applied to the design of automated power and free handling systems, using actual case studies to create and support a practical approach to design and implementation of these types of systems. The IDEF process mapping approach is used to encompass these design tools and system requirements, to recommend a generic process methodology for power and free systems design. The case studies consisted of three actual installations within the Philips Components Ltd facility in Durham, a manufacturer of television tubes. Power and free conveyor systems at PCL have assumed increased functions from the standard conveyor systems, ranging from stock handling and buffering, to type sorting and flexible product routing. In order to meet the demands of this flexible manufacturing strategy, designing a system that can meet the production objectives is critical. Design process activities and engineering considerations for the three projects were reviewed and evaluated, to capture the generic methodologies necessary for future design success. Further, the studies were intended to identify both general and specific criteria for simulating power and free conveyor handling systems, and the ingredients necessary for successful discrete event simulation. The automated handling systems were used to prove certain aspects of building, using and analysing simulation models, in relation to their anticipated benefits, including an evaluation of the factors necessary to ensure their realisation. While there exists a multitude of designs for power and free conveyor systems based on user requirements and proprietary equipment technology, the principles of designing and implementing a system can remain generic. Although specific technology can influence detailed design, a common, consistent approach to design activities was a proven requirement In all cases. Additionally, it was observed that no one design tool was sufficient to ensure maximum system success. A combination of both analytical and simulation methods was necessary to adequately optimise the systems studied, given unique and varying project constraints. It followed that the level of application of the two approaches was directly dependent on the initial engineering project objectives, and the ability to accurately identify system requirements

Petri net approaches for modeling, controlling, and validating flexible manufacturing systems

In this dissertation, we introduce the fundamental ideas and constructs of Petri net models such as ordinary, timed, colored, stochastic, control, and neural, and present some studies that emphasize Petri nets theories and applications as extended research fields that provide suitable platforms in modeling, controlling, validating, and evaluating concurrent systems, information systems, and a versatile dynamic system and manufacturing systems;We then suggest some of extensions that help make Petri nets useful for modeling and analyzing discrete event systems and manufacturing systems models based on the context of a versatile manufacturing system, and applies extended Petri nets models to several manufacturing systems such as an assembly cell, an Automated Palletized Conveyor System, and a tooling machine to show increased modeling power and efficient analysis methods;Finally, Validation methods are presented for these models and results of a performance analysis from a deterministic and stochastic model are used to reorganize and re-evaluate a manufacturing system in order to increase its flexibility

Sustainable Living Factories for Next Generation Manufacturing

To be profitable and to generate sustainable value for all stakeholders, next generation manufacturers must develop capabilities to rapidly and economically respond to changing market needs while at the same time minimizing adverse impacts on the environment and benefiting society. 6R-based (Reduce, Reuse, Recycle, Recover, Redesign and Remanufacturing) sustainable manufacturing practices enable closed-loop and multi-life cycle material flow; they facilitate producing more sustainable products using manufacturing processes and systems that are more sustainable. Reconfigurable Manufacturing Systems (RMS) and its characteristics of scalability, convertibility, diagnosability, customization, modularity and integrability have emerged as a basis for living factories for next generation manufacturing that can significantly enhance the system sustainability by quickly adjusting system configuration and production processes to meet the market needs, and maintain the system values for generations of products. This paper examines the significance of developing such next generation manufacturing systems as the basis for futuristic sustainable living factories by adapting, integrating and implementing the RMS characteristics with the principles of sustainable manufacturing to achieve value creation for all stakeholders

Petri net modeling and analysis of an FMS cell

Petri nets have evolved into a powerful tool for the modeling, analysis and design of asynchronous, concurrent systems. This thesis presents the modeling and analysis of a flexible manufacturing system (FMS) cell using Petri nets. In order to improve the productivity of such systems, the building of mathematical models is a crucial step. In this thesis, the theory and application of Petri nets are presented with emphasis on their application to the modeling and analysis of practical automated manufacturing systems. The theory of Petri nets includes their basic notation and properties. In order to illustrate how a Petri net with desirable properties can be modeled, this thesis describes the detailed modeling process for an FMS cell. During the process, top-down refinement, system decomposition, and modular composition ideas are used to achieve the hierarchy and preservation of important system properties. These properties include liveness, boundedness, and reversibility. This thesis also presents two illustrations showing the method adopted to model any manufacturing systems using ordinary Petri nets. The first example deals with a typical resource sharing problem and the second the modeling of Fanuc Machining Center at New Jersey Institute of Technology. Furthermore, this thesis presents the analysis of a timed Petri net for cycle time, system throughput and equipment utilization. The timed (deterministic) Petri net is first converted into an equivalent timed marked graph. Then the standard procedure to find the cycle time for marked graphs is applied. Secondly, stochastic Petri net is analyzed using SPNP software package for obtaining the system throughput and equipment utilization. This thesis is of significance in the sense that it provides industrial engineers and academic researchers with a comprehensive real-life example of applying Petri net theory to modeling and analysis of FMS cells. This will help them develop their own applications

Component-based control system development for agile manufacturing machine systems

It is now a common sense that manufactures including machine suppliers and system integrators of the 21 st century will need to compete on global marketplaces, which are frequently shifting and fragmenting, with new technologies continuously emerging. Future production machines and manufacturing systems need to offer the "agility" required in providing responsiveness to product changes and the ability to reconfigure. The primary aim for this research is to advance studies in machine control system design, in the context of the European project VIR-ENG - "Integrated Design, Simulation and Distributed Control of Agile Modular Machinery"

Discrete Event Simulation Implemented in a Virtual Environment

Virtual reality (VR) technology provides a human-computer interface that allows participants to interact naturally with digital objects which are represented as three-dimensional images that occupy positions in a three-dimensional world. Related to problems of engineering design and manufacturing, this new technology offers engineers the ability to work with computer models in a three-dimensional, immersive environment. This paper describes a virtual reality application where the results of a discrete event simulation of a manufacturing cell are integrated with a virtual model of the cell to produce a virtual environment. The program described in this paper, the VRFactory, combines results from a commercial discrete event simulation program, SLAM II, with a virtual environment. This allows the user to investigate, using three-dimensional computer models, how various changes to the manufacturing cell affect part production. This investigation is performed while immersed in a computer-generated three-dimensional representation of the cell. Existing discrete event programming software allows only two-dimensional views of the factory as the parts progress through the simulation. Parts are shown only as primitive geometric shapes on the computer monitor and instantaneously move from one station to the next. The virtual environment implementation of the SLAM II results allows users to experience the simulation in a fully immersive three-dimensional digital environment. The virtual environment used here is a CAVE™-like projection screen-based facility called the C2, which is located at Iowa State University. This paper describes the creation of the VR model of the manufacturing cell, the animation of the environment and the implementation of the results of the discrete event simulation

Development of a reconfigurable assembly system with enhanced control capabilities and virtual commissioning

Thesis (M. Tech. (Engineering: Electrical)) -- Central University of technology, Free State, 2013The South African (SA) manufacturing industry requires developing similar levels of sophistication and expertise in automation as its international rivals to compete for global markets. To achieve this, manufacturing plants need to be managed extremely efficiently to ensure the quality of manufactured products and these plants must also have the relevant infrastructure. Furthermore, this industry must also compensate for rapid product introduction, product changes and short product lifespan. To support this need, this industry must engage in the current trend in automation known as reconfigurable manufacturing. The aim of the study is to develop a reconfigurable assembly system with enhanced control capabilities by utilizing virtual commissioning. In addition, this system must be capable of assembling multiple different products of a product range; reconfigure to accommodate the requirements of these products; autonomously reroute the product flow and distribute workload among assembly cells; handle erroneous products; and implement enhanced control methods. To achieve this, a literature study was done to confirm the type of components to be used, reveal design issues and what characteristics such a system must adhere to. Software named DELMIA was used to create a virtual simulation environment to verify the system and simultaneously scrutinize the methods of verification. On completion, simulations were conducted to verify software functions, device movements and operations, and the control software of the system. Based on simulation results, the physical system was built, and then verified with a multi agent system as overhead control to validate the entire system. The final results showed that the project objectives are achievable and it was also found that DELMIA is an excellent tool for system verification and will expedite the design of a system. By obtaining these results it is indicated that companies can design and verify their systems earlier through virtual commissioning. In addition, their systems will be more flexible, new products or product changes can be introduced more frequently, with minimum cost and downtime. This will enable SA manufacturing companies to be more competitive, ensure increased productivity, save time and so ensure them an advantage over their international competition