Modular machine tools: Design and barriers to industrial implementation

The Reconfigurable Manufacturing System (RMS) paradigm has been developed to address challenges in the design of manufacturing systems and equipment that will meet the demands of modern manufacturing. This research involved the development of Modular Reconfigurable Machines (MRMs); as an emerging technology in reconfigurable manufacturing. MRMs are mechanically modular machines. The modularity permits the kinematic architecture and processing functions of the machine to be reconfigured to meet changing production requirements. This paper will focus on aspects of the mechanical design and the development of a control system that supported the modularity and reconfigurability of the mechanical platform. A modular electronic system is presented that is characterized by a plug and play approach to control scalability. This is complemented by a software architecture that has been developed with a focus on hardware abstraction for the management of an augmented mechanical and electronic architecture. The implications of MRMs for RMSs are discussed and key inhibitors to industrial implementation are identified.     

Domain-specific application analysis for customized instruction identification

With the increasing importance of Application Domain Specific Processor (ADSP) design, a significant challenge is to identify special-purpose operations for implementation as a customized instruction. While many methodologies have been proposed for this purpose, they all work for a single algorithm chosen from the target application domain. Such algorithm-specific approaches are not suitable for designing instruction sets applicable to a whole family of related algorithms. For an entire range of related algorithms, this paper develops a methodology for identifying compound operations, as a basis for designing “domain-specific” Instruction Set Architectures (ISAs) that can efficiently run most of the algorithms in a given domain. Our methodology combines three different static analysis techniques to identify instruction sequences common to several related algorithms: identification of (non-branching) instruction sequences that occur commonly across the algorithms; identification of instruction sequences nested within iterative constructs that are thus executed frequently; and identification of commonly-occurring instruction sequences that span basic blocks. Choosing different combinations of these results enables us to design domain-specific special operations with different desired characteristics, such as performance or suitability as a library function. To demonstrate our approach, case studies are carried out for a family of thirteen string matching algorithms. Finally, the validity of our static analysis results is confirmed through independent dynamic analysis experiments and performance improvement measurements.     

基于流密码的可重构处理结构及其专用指令集研究

在对多种流密码算法生成结构进行分析的基础上,提出一种基于流密码的可重构处理结构,并在总结重构流密码算法使用频率较高的基本操作类型的基础上,为该流密码可重构处理结构设计了一种专用指令集。描述了指令的具体格式,并对指令性能进行了评估。结果表明,该指令集作用在该流密码可重构结构上可灵活高效地实现多种流密码算法。     

Technical investment planning of flexible manufacturing systems—The application of practice-oriented methods

Flexible manufacturing systems (FMS) exhibit a high degree of automation of the machining system and of the workpiece, and for the information flow systems. Therefore, these systems are amongst the most complex production installations and their technical investment planning must be undertaken with great care.This paper introduces a strategic planning procedure and describes auxiliary aids for the selection of the components and for structuring of the overall system. Computer programs for the selection of machine tools and for the simulation of the manufacturing process sequence are part of this procedure. The application of the methods is illustrated by means of several problem situations arising from industrial production companies; the examples show the practical usefulness of the developed auxiliary techniques. The planning accuracy possible by these methods reduces the investment risk associated with the use of these complex manufacturing systems.Also described is an integrated system for the technical investment planning of flexible manufacturing systems which comprises both existing methods and new auxiliary means for planning the machining systems and the technical/organizational overall concept.     

Technology of the unmanned operation of flexible manufacturing systems

In this paper the hardware structure of a flexible manufacturing system and the information flow for operation of the system are reviewed first. Then the technology required for the unmanned operation of the system, especially monitoring the machining state, control of the geometrical accuracy of a workpiece and monitoring the machine operation are described in detail. Finally the technical and social tasks required for development of a flexible manufacturing system in the future are discussed.     

Hardware accelerator for molecular dynamics: MDGRAPE-2

We developed MDGRAPE-2, a hardware accelerator that calculates forces at high speed in molecular dynamics (MD) simulations. MDGRAPE-2 is connected to a PC or a workstation as an extension board. The sustained performance of one MDGRAPE-2 board is 15 Gflops, roughly equivalent to the peak performance of the fastest supercomputer processing element. One board is able to calculate all forces between 10 000 particles in 0.28 s (i.e. 310000 time steps per day). If 16 boards are connected to one computer and operated in parallel, this calculation speed becomes ∼10 times faster. In addition to MD, MDGRAPE-2 can be applied to gravitational N-body simulations, the vortex method and smoothed particle hydrodynamics in computational fluid dynamics.     

The evolving factory of the future: Integrating manufacturing and information systems

In recent years there have been rapid developments in both manufacturing and information technologies and their systems. Advances have occured so rapidly that often the results has been “islands” of automation and information subsystems, such as CAD/CAM, robotics, group technology, and office automation. Some recent developments, however, provide capabilities for integrating these “islands” into systems which both improve manufacturing productivity and produce more meaningful management information. Integrated systems seem imminent. Suggestions that could help ensure a smooth evolution toward these systems are made and some conclusions are drawn.     

可重构制造系统的合弄结构研究

可重构制造系统在激烈的市场竞争和产品品种、产品数量陡变的环境中,能够快速重构制造系统环境。该文采用合弄结构对制造系统的基本结构框架进行了分析,建立了基于合弄结构的可重构制造系统的结构框架。     

The human element: Its impact on the productivity of advanced batch manufacturing systems

Introducing highly automated machinery combining direct numerical control capabilities with automated material handling could potentially revolutionize batch production. However, experience suggests that projected uptime or utilization is not being achieved. Increased attention must be paid to employee satisfaction, motivation, incentive programs, and work group design.     

Human-computer interaction in manufacturing

The introduction of computers into the manufacturing environment has resulted in a significant impact on productivity and quality of manufactured products. Computers in manufacturing can be used to perform information processing, to control and monitor the manufacturing process, and to support the production operations in the plant. The use of computers does not, by itself, improve or degrade the skill levels required by operators. This is, in fact, a management function. Managers, product designers, and manufacturing personnel make choices to determine how machines and people will interact. When applied in the proper environment, computer-integrated manufacturing systems will increase machine utilization, reduce production cost, and improve productivity. The effective use of computers in manufacturing can be achieved by defining three major needs: manufacturing education, training, and research and development. This paper will study the elements of human-computer interactive systems and define requirements for proper use of computers in manufacturing.     

Recent trends in flexible automated manufacturing

In recent years, an important change in developing and implementing manufacturing systems can be observed in all industrialized countries. Due to intense international competition and the growth of personnel costs, companies are forced to use systems with a higher level of automation. At the same time, an increasing number of product variation—caused by adapting the products to customer requirements—demand more flexibility of machine tools and manufacturing systems.Basic types of computer-controlled flexible automated manufacturing systems will be shown and characterized by their special ranges of application. A planning procedure is presented which includes selecting a suitable systems structure such as; transfer line or flexible manufacturing system or automated manufacturing cell, and for determinating every single machine tool within the system. Examples of several new computer-controlled manufacturing systems which have been planned by the above planning procedure are presented with special regard to the evaluation of the system's economic performance.Finally, some rules are given for measuring the economic performance of automated manufacturing or assembly systems including automation of the handling functions.     

A survey of flexible manufacturing systems

In this report, the different flexible manufacturing systems used for machining and assembling in the following countries are reviewed: the United States, Japan, the Federal Republic of Germany, the German Democratic Republic, Italy, Great Britain, Sweden, Norway, France, Czechoslovakia and Hungary.Three categories of systems discussed are (1) flexible modules and units, (2) flexible transfer lines, and (3) “unaligned” flexible systems. Within each category are several sub-groups, divided up mainly according to the conveyor system and operating mode. This classification shows the effective French position in this field.     

Quantum Comparison Machines with One-Sided Error

It is always possible to decide, with one-sided error, whether two quantum states are the same under a specific unitary transformation. However we show here that it is impossible to do so if the transformation is anti-linear and non-singular. This result implies that unitary and anti-unitary operations exist on an unequal footing in quantum information theory. PACS: 03.67.-a     

Event rates and aggregation in hierarchical discrete event systems

A discrete event system (DES) is a dynamical system whose evolution in time develops as the result of the occurrence of physical events at possibly irregular time intervals. Although many DES's operation is asynchronous, others have dynamics which depend on a clock or some other complex timing schedule. Here we provide a formal representation of the advancement of time for logical DES via interpretations of time. We show that the interpretations of time along with a timing structure provide a framework to study principles of the advancement of time for hierarchical DES (HDES). In particular, it is shown that for a wide class of HDES the event rate is higher for DES at the lower levels of the hierarchy than at the higher levels of the hierarchy. Relationships between event rate and event aggregation are shown. We define a measure for event aggregation and show that there exists an inverse relationship between the amount of event aggregation and the event rate at any two successive levels in a class of HDES. Next, we study how to design the timing structure to ensure that there will be a decrease in the event rate (by some constant factor) between any two levels of a wide class of HDES. It is shown that if the communications between the various DES in the HDES satisfy a certain admissibility condition then there will be a decrease in the event rate. These results for HDES constitute the main results of this paper, since they provide the first mathematical characterization of the relationship between event aggregation and event rates of the HDES and show how to design the interconnections in a HDES to achieve event rate reduction. Several examples are provided to illustrate the results.The authors gratefully acknowledge the partial support of the Jet Propulsion Laboratory. Please address all correspondence to K. Passino (email: passino@eagle.eng.ohio-state.edu).     

A performance evaluation model for FMS based on RAM and LCC using FACTOR/AIM

The objective of this study is to develop a general design and performance evaluation model for the system designers in the initial design phase of the integrated manufacturing system based on the RAM(Reliability, Availability and Maintainability) and life cycle cost(LCC). The methodology proposed in this research includes the following three-step generative approach. First, a deterministic approach to find the optimal system configuration for the initial system configuration is considered under the assumption that the system availability is one(no failure and maintenance), and in second step a stochastic simulation model based on RAM and LCC is developed. Using the results of this two-stage simulation, a system performance index(SPI) was developed for the performance evaluation of the system. In the last step we developed a simulation model using FACTOR/AIM to consider a variety of performance factors and compared the results through a sample example.     

Harnessing agile concepts for the development of Intelligent Systems

Traditional and current approaches to intelligent systems design, have led to the creation of sophisticated and computationally-intensive packages and environments, for a wide range of applications. This paper proposes methods with which to extend the functionality of such systems, borrowing knowledge management concepts from the field of Agile Manufacturing. As such, this paper proposes that the future of intelligent systems design should be based not only upon the continuing development of artificial intelligence techniques, but also effective methods for harnessing human skills and core competencies to achieve these aims. Amir M. Sharif: He obtained his BEng (Hons) in Aeronautical Engineering from City University (London) in 1994 and is a research student in the Department of Information Systems and Computing, Brunel University (UK) currently completing his Ph.D in artificial intelligence. Amir maitains close links with both industry and academia and research interests include Evolutionary and Knowledge Based Systems, IT/IS investment evaluation, Information Management and E-commerce/Supply Chain Management. He has published in internationally refereed journals and spoken at conferences world-wide and is a member of numerours computer science-related journal and conference program committee boards. He is an Associate Member of the Institute of Electrical Engineers (AMIEE) and also has student membership of the Association for Computing Machinery (ACM) and Institute of Electrical and Electronic Engineers.