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Über dieses Buch

This book contains the results of an Advanced Research Workshop that took place in Grenoble, France, in June 1988. The objective of this NATO ARW on Advanced Information Technologies for Industrial Material Flow Systems (MFS) was to bring together eminent research professionals from academia, industry and government who specialize in the study and application of information technology for material flow contro!' The current world status was reviewed and an agenda for needed research was discussed and established. The workshop focused on the following subjects: The nature of information within the material flow domain. Status of contemporary databases for engineering and material flow. Distributed databases and information integration. Artificial intelligence techniques and models for material flow problem solving. Digital communications for material flow systems. Robotics, intelligent systems, and material flow contro!' Material handling and storage systems information and contro!' Implementation, organization, and economic research-issues as related to the above. Material flow control is as important as manufacturing and other process control in the computer integrated environment. Important developments have been occurring internationally in information technology, robotics, artificial intelligence and their application in material flow/material handling systems. In a traditional sense, material flow in manufacturing (and other industrial operations) consists of the independent movement of work-in-process between processing entities in order to fulfill the requirements of the appropriate production and process plans. Generally, information, in this environment, has been communicated from processors to movers.



Nature of Information in Material Flow Systems


Managing Information Complexity in Material Flow Systems

Few people seem to realize how extraordinarily complex the everyday activities involved in making products really are. Even those who are directly involved in these activities ordinarily see only a limited view of the entire process. In this paper, we would like to first call attention to some facts about the character of the information involved in manufacturing, emphasizing how difficult it is to manage This perspective is essential background to the real purpose of the paper, which is to examine alternative strategies for managing manufacturing information. Four strategies will be assessed, their merits and deficiencies will be compared, and a few comments will be added about hybrid methods.
James J. Solberg, Joseph A. Heim

Information Dynamics for Computer Integrated Product Realization

Shop floor disruptions are a major concern in today’s manufacturing environment. These disruptions can be minimized by a second generation system for computer aided product realization that integrates product development engineering activity with manufacturing engineering activity. The naturally occurring design changes, trade-offs, and iterations are kept in an information preparation environment where such instabilities can be managed and controlled. Stable information is then drawn onto the shop floor just when it is needed to drive shop processes. This is accomplished by managing and controlling the engineering information through a network of precedence controlled activities in a product realization process. Thus, product functionality can be maintained while manufacturing and marketing concerns are addressed. Data consistency is guaranteed through the management of the data generating process. Post-activity editing is not allowed and design iterations are controlled from a broad perspective of product development goals.
Charles A. Fritsch

Some Interactions of Information and Control in Integrated Automation Systems

The ready availability of inexpensive and standard communications hardware in the late 1980s, coupled with sufficient standardization of intermediate-layer protocols to make reliable machine-to-machine communication through any combination of standard devices a reality, has laid the groundwork for integrated automation on a grand scale. The contribution of the Manufacturing Automation Protocols (MAP) effort [MAP87], thus far, has been to speed delivery of this powerful communications capability to the industrial community. We must realize, however, that the delivery of the capability has now outstripped our ability to use it. On the factory floor, we have no devices which are prepared to control automation on a grand scale, and even worse, we have few controllers which are capable of contributing their local automation to any kind of integrated whole. The stumbling block is the lack of common languages or even a common experience base in which to communicate about automation tasks. We are now in the midst of a flurry of intellectual activity, on both sides of the Atlantic, developing languages, architectures, control techniques, data systems, communications systems and ultimately controllers to meet this challenge. In such a burst of activity, it is to be expected that experts in individual areas will hasten to solve the problems with which they are most conversant, and that certain interdisciplinary problems will fail to get timely attention. It is the purpose of this paper to draw attention to several such issues now, in the hope that they may get due consideration as the process advances. The issues discussed here are:
  • separation of data flow from control flow,
  • the impact of perfect communication on real-time control,
  • consistency of data with physical reality,
  • the significance of standard data models,
  • the identification of shared and private data.
Edward J. Barkmeyer

Data and Knowledge Methodologies in Material Flow Systems


Distributed, Intelligent Information System for Automated, Integrated Manufacturing Systems

As manufacturing systems have gravitated toward the Computer Integrated Manufacturing (CIM) ideal, they have become more dependent on capturing relevant data, storing it, operating on it and passing it between the members of the manufacturing system. As the systems become larger, this means increasing amounts of data to manage, higher complexity of operations on these data, higher number of requests and a need for significantly higher reliability and availability.
A model is presented here which strives to handle these highly demanding data management tasks for integrated manufacturing systems. A distributed system of cooperating, consistent, knowledge base sites is proposed that uses a semi-intelligent mechanism to predict the user processes in timing and data need. Data need is anticipated and the prepared information is stored in object frames, ready for quick access by the user. Test runs of a prototype version of this data storage and retrieval strategy demonstrate its utility.
Detlef M. Weber, Colin L. Moodie

Applying Distributed Artificial Intelligence to Flexible Manufacturing

The information system for flexible manufacturing has become increasingly intelligent and distributed, primarily due to the technological advancements in the areas of artificial intelligence and computer networking. This paper presents a framework applying a distributed artificial intelligence (DAI) method for flexible manufacturing, where a manufacturing cell is treated as a problem solving agent. We will show the application of this DAI approach to the dynamic scheduling and configuring/reconfiguring of the manufacturing system.
Michael J. Shaw, Andrew B. Whinston

Combining Predicate Transition Nets and Rule Based Systems for Planning, Programming and Exception Handling in Manufacturing Process Control

This paper presents a method which allows to specify, to program and to simulate the control behavior of flexible assembly systems. A hierarchical top down approach for planning and programming of a robot based assembly cell is discussed. The cell which consists of multiple units like stationary robots, mobile robots and peripherals is used for product assembly operations. Synchronization and exception handling for each of the assembly processes has to be considered. For specification of the cell program predicate transition nets are used. The predicate transition net of the cell can be broken down into subnets and into device specific local nets which define the operation of each specific device. The work is supported by an ESPRIT-CIM project.
R. Dillmann, U. Negretto

A Knowledge-Based System for Production Equipment Selection and Layout

In this paper, a knowledge-based system (KBSMD) for selection of machines and material handling equipment and determining a layout is discussed. The approach presented involves solving a model for the equipment selection problem. This results in a selection of the type and number of machines and material handling equipment. Next, the system selects a model for machine layout and solves it using an algorithm. It then uses the knowledge stored in the knowledge-base to incorporate qualitative aspects not considered in the equipment selection and layout models and modifies the solutions accordingly. Thus the system utilizes the optimization and knowledge-based approaches to solve the manufacturing system design problem.
Andrew Kusiak, Sunderesh S. Heragu

Specifications for Knowledge Representation in Intelligent Systems Layout Design Environments

Working in layout design may sometimes be a frustrating experience since it shares a basic attribute with riding a bicycle. Most six years old kids know how to ride a bike. The same way, most employees in the company, be they machine operator, intern student, or president, are able to draw a layout of the plant. They simply have to cut themselves some representative templates of the various cells in the shop, then lay them out over a grid paper, in a similar way as you do a 50-piece puzzle, being careful not to grossly violate the major flow patterns perceived in the system. However, companies have never, and especially not today, been embarked in a sunday afternoon country ride. They are engaged in a Tour-de-France like competition with the best in the business from all over the world.
Benoit Montreuil

Robotics and Communications


The Impact of Advances in Information Technology on Interactive Robotics

Automated knowledge-based machine interaction, or interactive robotics, is critical to the future development of robotic operations. Such interaction should include higher levels of intelligent behavior, as cooperation, substitution, context-driven response, and mutual error-recovery. This article details our recent and on-going research projects of such robotic machine interaction.
S. Y. Nof

The Karlsruhe Autonomous Mobile Assembly Robot

In this paper the architecture and functions of an autonomous mobile system are described. For the operation of such a system knowledge-based planning, execution and supervision modules are necessary which are supported by a multi-sensor system. The individual functions of such a vehicle are explained with the help of an autonomous mobile assembly robot which is being developed at the University of Karlsruhe. The vehicle contains a navigator, a docking module and an assembly planner. Navigation is done with the help of a road map under the direction of the navigator. The docking maneuver is controlled by sensors and the docking supervisor. The assembly of the two robot arms is prepared by the planner and controlled by a hierarchy of sensors. The robot actions are planned and controlled by several expert systems.
Ulrich Rembold

Knowledge Representation and Integration of Robot Assembly Applications

The knowledge representation and the design of data models are influenced by the various applications which are operating on these representation schemes. For the activities of design, planning, programming and simulation the same robot objects are referenced but different knowledge representations are used.
The requirements of automatic assembly planning, graphic supported offline programming, computer aided design and sensor integration for the representation of knowledge will be discussed in this paper. The results of this work will support the integration of complex systems like the KAMRO (Karlsruhe Autonomous Mobile Robot) into a CIM environment. The relevant objects of this research area are robots, parts, cell layouts, control programs etc. which are represented on various layers of abstraction with different data representations. This different data representations result from the special needs of the invidual activities. The merging of all separate activities into an integrated production systems working on common knowledge bases is necessary. For this purpose different knowledge representations like neutral CAD formats, various databases and Al tools have to be integrated. An object oriented representation of the most important objects is proposed as an approach to an integrated production system, because a homogen representation of all the specific knowledge lead to a inefficient data management effort. The management of the large data objects should be done by conventional means like databases or file management systems.
S. Schneider

Results of the Development of a Manipulator with a very large reach

The paper gives an overview of the work performed in a national project by the companies Putzmeister, AEG and Dornier together with the IPA-Stuttgart.
The principal hardware and software is now completed and tested. The first results show that the specifications of the system can be realized.
Martin-Christoph Wanner, Alexander Schließmann

Global Path Planning Approaches for Material Movements in a Worksite

In various environments (e.g., manufacturing shopfloors, civil engineering construction sites, space) there is an increasing need to efficiently transport objects from locations to other locations. Although most practical material transportation robotic system built so far have been quite primitive, we believe that in many areas one can significantly gain in efficiency, reliability and flexibility by automatically planning the motions of the transportation devices. While process planning provides a high-level ‘logical’ and possibly ‘temporal’ specification of material movements, motion planning says how these movements are to be ‘physically’ carried out. Thus, motion planning is the natural intermediate stage between process planning and task execution. In this paper, we survey techniques for planning mobile robot paths among obstacles, which have been developed over the last few years. We focus on the so-called ‘global’ techniques. We describe in detail the three most common approaches, which are based on the notions of cell decomposition, free space retraction, and visibility graph, respectively. Within the first two approaches, we survey both the so-called exact and approximate techniques. Although this paper is far from exploring all the facets of motion planning, it gives a fundamental and detailed presentation of issues, which are of general interest to all motion planning problems. These issues are likely to be of prime importance in future material transportation systems.
Jean-Claude Latombe

The Need for a Generic Framework for Systems Integration

This paper outlines the need for a widely accepted generic framework for systems integration within manufacturing enterprises. The provisions of this framework would form a basis for the specification of integration projects and sub-components such as software packages in order to permit the interchange, reconfiguration, expansion and transferability of the whole or part solutions so generated. The overall aim is to allow a logical mapping of integration tools, implementations and solutions to physical resources at all phases from manufacturing system inception to operation so enabling rapid and cost-effective response to changes in products, markets, enabling technologies and manufacturing methodologies.
The discussion is based on the findings of systems integration studies at Loughborough University of Technology aimed at a flexible and adaptable approach to product realisation in electronic industries. More specifically, research findings are reported with respect to:
the need to proceed from a position of existing installed bases of manufacturing machines and operations, both automated and manual,
the integration of the activities of contemporary proprietary software packages with specific reference to production planning and control, and
the provision of an environment for the definition and realisation of interaction, synchronisation and organisation between manufacturing entities.
The approaches studied incorporate OSI computer network methodologies and products in the role of an underlying communication “utility”.
R. H. Weston, J. D. Gascoigne, C. M. Sumpter, A. Hodgson

Modeling Issues of Specific Material Flow Systems Functions


Some Issues in Controlling Integrated WIP Material Handling Systems

In an automated factory, material handling will be but one element of a hierarchical control system. Experience shows, however, that the computer controls for some highly automated work-in-process (WIP) handling systems are not consistent with strictly hierarchical architectures. In this context, we propose an approach to integrating the control of automated WIP handling within hierarchical process control and explore some of implications for the design of interfaces and coordinating mechanisms.
Leon F. McGinnis

Tool Management and Its Implications for Material Flow

Tool Management is a topic receiving increased attention, although diverse and narrow concepts of what is involved are still current. This paper reviews the aspects of tool management and presents three brief cases. The first illustrates the complexity of the logistics problem; the second the difficulties in planning and support despite automated tool handling; the third the operational problems in achieving communication links. The paper identifies areas where further research is needed, namely, the tool management practices, communication standards and effective modelling of tool management systems.
A. S. Carrie, U. S. Bititci

Issues in Design and Control of AS/RS

In this paper we deal with issues of design and control of AS/RS. Specifically, we focus on some recent developments in this area, which were part of four different studies that may affect the design and control of AS/RS. The first issue is concerned with the problem of which items (and at what levels) should be allocated to the AS/RS. The second issue deals with the problem of using class-based storage policies and dividing the items into groups so that the expected one-way travel time is minimized. The third issue deals with the actual design of the AS/RS, studying the effects of having smaller number of cranes than aisles. The fourth issue is concerned with the best container size in a warehouse. Although each one of these issues can be viewed as a separate entity (study), they are all connected with the important problem of better designing and controlling AS/RS.
Meir J. Rosenblatt

Knowledge Models for the Design and Management of Automated Storage and Retrieval Systems

The successful operation of every manufacturing facility or distribution center depends to a large extent on the efficient hadling, storage and flow controls of materials. A key component in many material flow activities is the Automated Storage and Retrieval System (AS/RS) which serves as an unmanned warehouse for raw material, work in progress inventories and finished goods. In this paper a new design and management methodology for AS/RS’s is developed and examined. It is based on knowledge structures, mathematical models and on the state-operator framework for problem solving. An industrial case study is used to illustrate the applicability of these concepts to the operational controls of a unit-load AS/RS. The impacts of recent developments in related information technologies, data representation schemes and industrial communications are also examined.
Abraham Seidmann

Guided Vehicle Systems: Information/Control System Implications of Alternative Design and Operation Strategies

Automated Guided Vehicle (AGV) systems continue to be a viable and flexible handling alternative for many low to medium flow, discrete parts handling requirements. Today, in addition to the towing vehicle, AGVs can be configured as unit load carriers, automatic guided pallet trucks, automatic guided fork trucks, or light load carriers. The automatically positioned stock selector (used for in-the-aisle picking) is also generally accepted as an AGV.
In this paper, assuming a pick & drop system based on unit load carriers, we describe current control methods for vehicle dispatching, and we examine their relationship to various empty vehicle dispatching policies developed in the AGV literature. Subsequently, we discuss further work needed in the area along the following directions: developing standard problems for evaluation purposes; analyzing the interaction between the system layout and the dispatching rules; analyzing the impact of machine processing times and the routing matrix; integrating or interfacing the AGV control system with higher level information systems; and evaluating the impact of self-guided vehicles.
Yavuz A. Bozer

Integration Models and Techniques


Materials Handling and Storage in Logistics Systems

The aim of this paper is firstly (in Part A) to set AHS in the context of the overall logistic chain and to highlight some aspects which have not received much attention from researchers. It will then (in Part B) explore one particular aspect in more depth, the development of guidance systems for automated guided vehicles (AGVs) with special reference to free-ranging capability. The paper deals only with unit load systems and will stress the linkages necessary between the physical material and information flows.
R. H. Hollier

GRAI Approach to Designing and Controlling Advanced Manufacturing System in CIM Environment

The design of Advanced Manufacturing System (AMS) is today one of the most complex task in the field of Computer Integrated Manufacturing (CIM). This design must fit with several constraints (costs, quality, flexibility, time) and must allow the best efficiency in the control of Manufacturing System (MS). The choice of equipment and software depends strongly from the result of this design activity and the consequences of a wrong choice could have disastrous consequences if we consider the amount of investment. For fifteen years, GRAI Laboratory has been developing methods to design and to control AMS. The objectives of this paper is to give the progress of this research and to show the recent development. We will organize our presentation in four parts. The first one presents the problematic of the research work, the second details the GRAI Method, the third shows how we can use the approach on an experimental way and the last describes the new researches.
Guy Doumeingts

LLAMA: A Layered Logical Architecture for Material Administration

Material handling systems are an information bridge between high-level shop floor control and the sensors and actuators at the factory floor. When such systems are engineered as a monolith, each must be custom-built, and the cost of modification and maintenance is high. Drawing on parallels between communications (moving data) and material handling (moving material), we propose a layered architecture analogous to the ISO OSI reference model for communications. This article defines the problem, discusses layered architectures in general and previous layered systems in particular, and describes the functions and interfaces of the layers in our system. This is a working paper describing work in progress, not a finished specification.
H. V. D. Parunak, R. Judd

Simulation Technology for the Design and Scheduling of Material Handling and Storage Systems

The primary objective in acquiring material handling systems is usually the same: find the best system to meet objectives at the least cost. The design and operation of material handling systems is a complex and difficult task. Material handling is also not exactly a prestigeous focus for a career in U.S. industry. Our best talent is rarely assigned to manufacturing, much less material handling.
In Europe and Japan, material handling has long been recognized as a critical link in the manufacturing chain. In fact, it is the key element of integration in modern manufacturing systems.
This article will explore the use of simulation technology as one tool in the design and scheduling of material handling components of production systems. Material handling is examined as it is perceived in industry vis-a-vis its critical role in integrated manufacturing. Simulation and Scheduling is reviewed from a historical perspective and simulation-based tools for designing and scheduling production systems discussed. An overview of some important applications is provided followed by an overview of research needs regarding simulation and material handling.
F. Hank Grant

Knowledge Based Approaches for Production Control an Assessment

With increased automation in the manufacturing process, planning and control of material flow in a factory is being performed by computer based systems. Control of the material flow involves responding to unanticipated events. In this paper, we review the major activities associated with the control process, and then evaluate current efforts to apply knowledge based techniques in performing them. Our assessment is that, while such efforts have met with some success in generating corrective responses, there still remains considerable room for the application of such techniques in the detection of exception conditions. Furthermore, under a hierarchical view of factory operations, knowledge based methods appear to provide a basis for aggregation/disaggregation of information necessary to detect exceptions and take corrective actions.
Amitava Dutta

Implementation and Management Issues


Information Processing in Material Flow System Management

Production Management in a manufacturing plant requires to handle flows of two types of “entities”:
  • product order, which must be propagated backward from a work stage to the upstream ones, to assign the production orders to each stage;
  • material & components, which must be transferred forward, from a stage to the downstream ones, to assure availability of items to be processed at each stage.
The aim of any Production Management (PM) System is that of synchronizing production order flows with item flows.
Two alternative approaches can be adopted in order to solve the PM Problem:
planning of production orders for all work stages in the plant, and “pushing” of items to the input buffers of all stages, according to planned loading conditions;
planning the throughput of the final stages, and “pulling”items from upstream stages, according to item consumption.
Depending on the adopted PM approach, different PM Architectures can be designed. Obviously, each one of them should be tuned on the market situation of the factory to be managed. To this aim, the question asked to the PM Architecture designer by a Production Manager is always of the following type:
“is it possible to compare PM Architectures, in front of a given evolution of the product orders in the future, and of a given structure of the plant?”.
The problem underlying this question is particularly important in case of factories composed by a number of plants, often located in different towns, i.e. distributed industrial environments where the management of item flows assumes a relevant importance. This paper will try to offer a theoretical solution to the above question. First, to allow a comparison of existing PM Procedures, a common formulation of both PM approaches will be stated, in case of a single-plant factory. SADT representations of the necessary INFO Systems (for collecting and addressing necessary information and planning/control decisions), for each one of the resulting PM Architectures, will be derived. Then, the multiplant situation will be analyzed, to discuss the necessary generalizations (and, possibly, integration) of PM Architectures assuring a reasonable efficiency in front of variable demands.
Agostino Villa

CIM System Development for Small to Medium Size Discrete-Parts Manufacturing Companies

This paper discusses analysis and design tools for use by small and medium sized discrete-parts manufacturing companies for CIM system development. The development lifecycle consists of eight primary technical tasks: Problem Analysis, Requirements Definition, Preliminary Design, Detail Design, Construct & Verify, Integrate & Validate, Implementation & User Acceptance, and Maintenance & Support. The discussion is based upon experiences with the CIM/GEMS project, a DKr 15 million (US$ 2.3 million) project to develop Danish industry’s ability to manufacture the manufacturing system.
Robert E. Young

An Approach to Solve Workshop Real Time Scheduling Problems

Real time production scheduling problems are considered, when the items to be performed have release times and due dates. The real time scheduling decision process is based on an original approach, aiming at the search for characteristics of schedules compatible with the main manufacturing constraints to be satisfied (limit times, item routings, limited amount of available resources). At any time when a decision has to be made in real time, these characteristics allow to select actions which are coherent with the constraints. Two procedures to search for these characteristics and to use then for real time scheduling are described
Jacques Erschler, François Roubellat

Cybernetics Approach to Material Flow Control

The world of today is very often characterized as the beginning of the era of information. The value of information has never been so high in the past as nowadays. The problem we have to solve is not to have just any information, but the problem we need to tackle is to find the correct information at the right time out of the abundance of information which overflows us every day. The information networks we operate in companies, towns, states which function via telephones, mail or satellites enable us to be informed about incidents on the other side of the planet which have only happened a few seconds ago. — Thus information ties the elements of our world very close together. This entails that reciprocal relations of the world’s elements do not only exist, but that their importance in the daily life increases heavily.
Detlef F. Pape

Research Panel Reports

Research Panel Reports

An important objective of the advanced research workshop is to stimulate research panel discussions by the participating scientists. The participants were divided to four panels. Each panel had an assigned chairman or co-chairmen, and a provacator, who had all prepared in advance to lead the panel discussions. The panels met in parallel and focused on four main themes, which are significant to the workshop topic:
  • Material Flow Data and Knowledge
  • Communications and Intelligent Systems
  • Planning and Control Models
  • Implementation and Economics
Shimon Y. Nof, Colin L. Moodie


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