In a world of rapid change, production companies are faced with major challenges. They have to deal quickly to an increase in competition and individual customer requests. New technologies and organizational structures like RFID or decentralized and real-time based production control can handle these challenges. The analysis of a production process and the selection of appropriate technical solutions often proves to be difficult and cost intensive. Previous simulation approaches are frequently combined with high effort in order to state credible propositions regarding suitability and economic efficiency. This paper presents a new opportunity towards overcoming these disadvantages. The approaches of computer-based simulation and model factories are combined into a new simulation approach with reduced effort. For the purpose of documentation of simulated processes the Value Stream Design method is extended towards the requirements resulting from autonomous production control. For this purpose additional symbolism, data dictionaries and key figures are introduced.
The last decade has revealed a profound paradigm change with respect to the organization and control of logistic systems. Forced by recent trends in the organization of enterprises and new market requirements, logistic systems are confronted with new prospects and challenges that do not fit with the paradigm of central planning. The involvement of several decision making units in one supply chain, the management of real-time data, the division of work and decision making, and a high market dynamic require innovative decision support and business information concepts. Additionally, wide-area-computer networks, ubiquitous computing, and 24-h-data availability provide a data basis as well as an infrastructure for a joint decision making among autonomous entities (e.g. agents). While the paradigm of a monolithic central control of all activities has been in the focus of research and application for several decades, the last years have revealed the intrusion of noncentralized approaches for designing, configuring, and deploying complex systems. More than in other disciplines, there is a paradigm shift in logistics from hierarchical systems to heterachical systems, especially concerning the design and control of compound systems. In order to explore and establish a base for using and exploring the capabilities of distributed decision making, fundamental research must be executed. In the Collaborative Research Centre 637 ââAutonomous Cooperating Logistic ProcessesâA Paradigm Shift and its Limitationsââ, funded by the German Research Foundation, an interdisciplinary group of scientists investigates the prospects and limitation of the interactive decision making among several components of a logistic system. The components of a hierarchically organized logistic system are externally controlled units, which have only limited decision rights. On the other hand, in heterarchical systems, the components constituting a compound system are autonomous units, which interact with each other on their own responsibility, and they are provided with local intelligence and emancipated decision authority. Heterarchical structures grant autonomy to the single system components in order to enable decentralized decision making. Autonomy of components presupposes that interactive units in non-deterministic systems are able to decide and act on their own authority. Autonomous units representing components of a complex logistic system can be found on different levels of appearance and in several contexts. At the lowest level, there are agents representing autonomous physical logistic units like parcels or containers, which are capable and allowed to decide on their handling. At the medium level, there are autonomous planning agents like human schedulers or software agents being responsible for the decisions in a delimited problem area and cooperating with agents responsible for adjacent areas. Finally, at the upper level, there are autonomous organizational units, e.g., profit centers of an enterprise or partners in a collaborative system constituting a coalition following at least one common goal. In practice, most complex logistics systems are built in a hierarchical manner. Currently, there is a tendency to redesign such systems in a heterarchical way by constituting a set of interrelated, partly autonomous, components for the construction of the total system. The objective of the redesign is to achieve a higher degree of robustness and a positive emergence of the total system [1] by increasing H. Kopfer (&) J. Schonberger Lehrstuhl fur Logistik, FB 7, Universitat Bremen, Wilhelm-Herbst-Strase 5, 28359 Bremen, Germany e-mail: kopfer@uni-bremen.de
The concept of holonics manufacturing systems (with divided intelligence) is the most intelligent, autonomous, elastic, units collaborating with each other. The idea takes as a starting point the fact that the today's environmental circumstances are exceptionally unsettled; there is need for companies with the ability to respond quickly to maintain competitiveness. Holonic manufacturing systems (HMS) have been recognized as a paradigm to accommodate changes and meet customersâ requirements flexibly based on the notion of the holon, flexible and decentralized manufacturing architecture. Koestler proposed the word âholonâ to describe a basic unit of organization in biological and social systems. A holon is an autonomous, co-operative and intelligent entity able to collaborate with other holons to process tasks. Autonomy and cooperation are two important characteristics of holons. In this study, we investigated a Holonic Manufacturing Systems for dry-working machine group.
This paper presents the concept of Autonomous Production Systems (APS), which are the organizational units upon which enterprises can be built and managed in order to better face the globalization challenges. We believe that companies organized as networks of APSs are better prepared to respond to the new economy challenges than organized in a hierarchical fashion. The way a traditional company can be reorganized in terms of a network of APSs using decentralized management is also explored in this article. We propose an approach to create and operate Virtual Enterprises either based on APSs or based on traditional companies. A Production Planning and Control system to operate Virtual Enterprises is also proposed in this paper using the concept of Bill of Materials and Movements.
Hans Kurt Tönshoff, Marcel Winkler, Jan C. Aurich
Holonic manufacturing is a new approach to the organization of decentralized autonomous and cooperative manufacturing systems. Such systems lead to new requirements for a product model, which can not be entirely fulfilled with today's product modelling techniques. This paper outlines the new requirements for product modelling and presents an approach to a solution based on the use of features technology.>
The development of a "Next Generation Manufacturing System" is currently an active area of research worldwide. The research described in this dissertation addresses one sub-element within this research area; namely, the demonstration of a decentralized, automated production architecture. The goal of the work is to increase the ability of a manufacturing enterprise to respond to rapid technological and market change in the post-2000 global economy. The research is comprised of three objectives; definition of a decentralized organizational structure of autonomous production activities, implementation of the defined organization in a real world manufacturing environment, and a comparison of historical (centralized architecture) performance data and decentralized performance data. To accomplish these objectives, the proposed production architecture is implemented at a real world manufacturing site and performance data are acquired and tested against a stated hypothesis. The research entails the modification of a selected electronics module assembly activity in the following ways: 1) comprehensive automation of assembly processes; 2) simplification of production practice through a minimization of operator interaction and a reduction of assembly transaction points requiring operator intervention; and 3) restructuring of organizational functions resulting in decentralization and operational autonomy. The null hypothesis was successfully rejected and it was shown that the implementation of automation, simplification, and decentralization resulted in an enhancement of production performance (i.e., a reduction in throughput time, labor cost, overhead cost, and total product cost) without degrading production quality. A test of the null hypothesis based on the data indicates a statistically significant (i.e., p less than or equal to 0.05) reduction in throughput time, labor cost, overhead cost, and total product cost while no statistically significant difference in the before and after production quality data was shown. A possible interpretation of these results is that the implementation of automation, simplification, and decentralization did result in a reduction in the labor cost, overhead cost, and total product cost and did not result in a degradation in production quality.