Loading flexible manufacturing systems: a heuristic approach

In this study, heuristic algorithms are developed for loading Flexible Manufacturing Systems. The heuristic approach is an efficient way of planning the FMS with multiple nonlinear loading objectives.     

Modular production systems: a new manufacturing paradigm

It is well recognized that manufacturers of consumer goods throughout the world are facing major new demands, including shorter product life-cycles and increasing competition. In response, companies are restructuring and moving away from traditional process-centred work practices in favour of concurrent engineering methods. In particular, design for manufacture has gained widespread recognition as a means of reducing production costs and lead times. However, optimal design for manufacture is difficult to achieve using current-day work organization and business structures. An underlying problem is the lack of a scientific framework for production. To address this need, this paper proposes a radical and far-reaching new manufacturing paradigm based upon on building production systems from standardized modular machines. The manufacturing concept, termed modular production systems (MPS), is aimed specifically at hard low- to medium-technology consumer products, as typified by goods such as childrens toys and kitchen appliances. The rationale for MPS as a means of enabling concurrent product and production system design is put forward, and the long-term implications and work required to establish the concept are discussed.     

Reconfigurable manufacturing systems: Key to future manufacturing

Presented in this article is a review of manufacturing techniques and introduction of reconfigurable manufacturing systems; a new paradigm in manufacturing which is designed for rapid adjustment of production capacity and functionality, in response to new market conditions. A definition of reconfigurable manufacturing systems is outlined and an overview of available manufacturing techniques, their key drivers and enablers, and their impacts, achievements and limitations is presented. A historical review of manufacturing from the point-of-view of the major developments in the market, technology and sciences issues affecting manufacturing is provided. The new requirements for manufacturing are discussed and characteristics of reconfigurable manufacturing systems and their key role in future manufacturing are explained. The paper is concluded with a brief review of specific technologies and research issues related to RMSs.     

Performance evaluation of manufacturing systems: a spreadsheet model

In this paper, we describe the spreadsheet modeling of manufacturing systems which are represented by multi-server and multi-product open networks. The spreadsheet software is characterized by easy data manipulation, on-screen numerical and visual feedback, fast calculation (what-if analysis), and its availability. So far, most spreadsheet models of this type have been used to solve static and deterministic problems in manufacturing systems, ignoring most of the uncertainties. We propose here that a spreadsheet can be implemented for capturing not only static features but also stochastic behaviour of manufacturing systems. The experiments show that the results from the spreadsheet model are reasonably close to those from the other existing approaches. The proposed spreadsheet model could be applied by an engineer to the modeling of manufacturing systems, especially for a first-cut design stage, utilizing his/her own spreadsheet software.     

Nonlinear measures: a new approach to exponential stabilityanalysis for Hopfield-type neural networks

In this paper, a new concept called nonlinear measure is introduced to quantify stability of nonlinear systems in the way similar to the matrix measure for stability of linear systems. Based on the new concept, a novel approach for stability analysis of neural networks is developed. With this approach, a series of new sufficient conditions for global and local exponential stability of Hopfield type neural networks is presented, which generalizes those existing results. By means of the introduced nonlinear measure, the exponential convergence rate of the neural networks to stable equilibrium point is estimated, and, for local stability, the attraction region of the stable equilibrium point is characterized. The developed approach can be generalized to stability analysis of other general nonlinear systems.     

Production control of manufacturing systems: a multiple time scaleapproach

In this note, a stochastic production model containing processes with different time scales is developed. It is shown that if the time scales of the processes are very different, some hierarchical algorithms that are much more efficient than the standard policy iteration method can be developed to find the optimal production control. Moreover, if the time scales fall far apart, the optimal control of a deterministic limiting problem depending only on the mean characteristics of the processes can be used to approximate the optimal control of the original problem. The limiting problem has much lower dimension than its original counterpart and thus is much easier to solve. A numerical example is used to illustrate the potential of the proposed approach     

Flexible manufacturing systems

Flexible manufacturing is an important new technology. The article explains the concept of flexible manufacturing, outlines its worldwide use, and comments on development trends.     

Modelling manufacturing systems

The traditional approach of extrapolating past experience in order to predict the performance of manufacturing facilities has been found to be quite inadequate for automated manufacturing systems. The need to identify the key factors influencing performance has led to the development of both simulation and analytical models to help in design, operation and control. The basic approaches to the development of such models will be outlined and illustrated with examples pertaining to assembly lines, automatic transfer lines, and flexible manufacturing systems. The value of formal models will be demonstrated by examples of the insights which can be gained through their use. The paper will conclude with a discussion of current research needs in both model development and model application.     

Model-based manufacturing integration: A paradigm for virtual manufacturing systems engineering

Current manufacturing system design methodologies produce multiple models of the eventual manufacturing system. These models reflect either the designers view of some subsystem, like materials handling, some level of abstraction, or some developmental stage in the design of the system. These models serve to break the complex system design into smaller, more manageable sized problems. This paper makes a case for the need to integrate these models before the physical system is constructed.     

Modelling manufacturing systems: A birth-death approach

An approximation method for modelling a manufacturing system is introduced. The system is considered as a queueing network, where each queue is limited in size, and interarrival and processing times are exponentially distributed. The birth-death approach is considered and an approximation method to reduce the dimension of the model is developed. The results are the marginal probability distribution of the number of units in each queue; other performance indices, such as mean queue lengths, utilizations of the working stations, and throughput can be easily obtained. The general procedure is applied to model, for example, queues in tandem, a split node, and a more complex network of queues. Simulation and, when possible, comparison with the exact solution show an acceptable error level of the proposed method.     

Appropriate technology for manufacturing: Some management issues

This paper introduces the idea of appropriate technology and applies it to the choices organisations make when designing, implementing and managing advanced manufacturing technologies. Five sets of choices are considered: the type and level of technology; the allocation of functions between humans and machines; the role of humans in advanced systems; the organisation structures to support them; and the ways in which people participate in their design. The paper concludes that most organisations are not effective at developing and implementing appropriate technologies, and that ergonomists have failed to meet the needs of technologies and managers in these areas.     

Designing Holonic manufacturing systems

This paper discusses the design of Holonic manufacturing systems (HMS), with emphasis on manufacturing control. First, it discusses the concept of a Holonic system. Second, it presents the HMS reference architecture for manufacturing control. Third, it addresses the overall design problem, i.e. designing both the holonic control system and the underlying manufacturing system. Finally, the paper addresses the design and development of the control software itself.     

Bio-inspired multi-agent systems for reconfigurable manufacturing systems

The current market's demand for customization and responsiveness is a major challenge for producing intelligent, adaptive manufacturing systems. The Multi-Agent System (MAS) paradigm offers an alternative way to design this kind of system based on decentralized control using distributed, autonomous agents, thus replacing the traditional centralized control approach. The MAS solutions provide modularity, flexibility and robustness, thus addressing the responsiveness property, but usually do not consider true adaptation and re-configuration. Understanding how, in nature, complex things are performed in a simple and effective way allows us to mimic nature's insights and develop powerful adaptive systems that able to evolve, thus dealing with the current challenges imposed on manufacturing systems. The paper provides an overview of some of the principles found in nature and biology and analyses the effectiveness of bio-inspired methods, which are used to enhance multi-agent systems to solve complex engineering problems, especially in the manufacturing field. An industrial automation case study is used to illustrate a bio-inspired method based on potential fields to dynamically route pallets.     

ManufAg: a multi-agent-system framework for production control of complex manufacturing systems

In this paper, we present a framework for the implementation of multi-agent-systems for production control of complex manufacturing systems. We present the results of a requirement analysis for production control systems for complex manufacturing systems; then we describe the framework design criteria. Our framework supports the inclusion of distributed hierarchical decision-making schemes into the production control. Furthermore, in order to increase the coordination abilities of multi-agent-systems, we follow the decision-making and staff agent architecture suggested in the PROSA reference architecture. We indicate the usage of the framework for designing and implementing an agent-based production control system for semiconductor manufacturing processes in a case study.