Table Of ContentProgress in Materials Handling and Logistics
Editors: John A. White, Ira W Pence
-=--
Material Handling Research Center
- Georgia Institute of Technology
Progress in Materials
Handling and Logistics
Volume 1
Springer-Verlag
Berlin Heidelberg GmbH
Prof. John A. White
Regents' Professor and Eugene C.
Gwaltney Professor
School of Industrial and Systems Engineering
Georgia Institute ofTechnology
Atlanta, GA 30332-0206
USA
Dr. Ira W Pence, Jr.
Director
Material Handling Research Center
Georgia Institute ofTechnology
Atlanta, GA 30332-0206
USA
ISBN 978-3-662-09514-0
Library ofCongress Cataloging-in-Publication Data
Progress in materials handling and logistics / J.White, I.W. Pence, eds.
ISBN 978-3-662-09514-0 ISBN 978-3-662-09512-6 (eBook)
DOI 10.1007/978-3-662-09512-6
1. Materials handling--Automation. 2. Flexible manufacturing systems.
1. White, John A.ll. Pence, I.w. (Ira w.)
TS180.P74 1989
658.T81--dc 20 89-26085
This work is subject to copyright. AII rights are reserved, whetherthe whole orpart ofthe material is
concerned, specifically the rights of translation, reprinting, re-use of illustrations, broadcasting,
reproduction on microfilms orin otherways,and storage in data banks. Duplication ofthis publicatian
or parts thereofis anly permitted underthe provisions ofthe German Copyright LawofSeptember9,
1965, in its version of June 24, 1985,and a copyright fee must always be paid. Violations fali underthe
prosecution act of the German Copyright Law.
© Springer-Verlag Berlin Heidelberg 1989
Originally published by Springer-Verlag Berlin Heidelberg New York in 1989
Softcover reprint ofthe hardcover Ist edition 1989
The use of registered names, trademarks, etc. in this publication does nat imply, even in the absence
of a specific statement, that such names are exempt from the relevant protective laws and regulations
and therefore free for general use.
2161130205432\0 -Printed on acid-free paper
ACKNOWLEDGEMENTS
The Editors would like to thank the staff of the Material Handling Research Center for
their support. Freida Breazeal co-ordinated the correspondence with the several
authors while Joene Owen did most ofthe typing and proofing of the several versions
of each chapter. We would also like to thank the Program Managers, Dr. R. Bohlan
der, Dr. S. Dickerson, Dr. M. Goetschalckx, Dr. L. McGinnis, and Dr. G. Sharp for
reviewing the many papers submitted and selecting those for inclusion in each area.
The graduate students conducting the research within the Center deserve a special
thank you for checking the technical accuracy of each chapter including the appropri
ateness of references, accuracy of equations, etc. The quality of the text owes much
to their devotion and attention to detail. The editors are especially indebted to several
of these students, Orner Bakkalbasi, Brett Peters, Dah-Chuan Gong, Steve Weber and
Eric Seeyave for preparing the many figures.
The editors wish to express its acknowledgement and appreciation to Elsevier
Science Publishers B.V. for their permission to reprint material originally appearing
in Material Flow, 2, (1985) within this book.
We wish to acknowledge the help and guidance of Dr. Brian Rooks of IFS
(Publication) Ltd in establishing the Topics in Material Handling and Logistics series
and for his assistance and patience in the preparation of this volume.
PREFACE
Material handling and logistics have become especially important to industrialists
because of the competitive advantage that results from using the right methods to
provide the right amount of the right material at the right place, at the right time, in
the right condition, in the right sequence, in the right orientation, and at the right cost.
But, what are the right methods? The emergence ofs ophisticated control systems,
coupled with advances in hardware design, has resulted in a wide variety oftechno
logical alternatives availablefor practically any application. Yet, with the emergence
ofj ust-in-time methods and the apparent success of the firms that have relied on the
use ofp eople and" simple" rules, rather than technology, the proper role ofh ardware
and software in material handling and logistics is open to debate. Despite all that has
been accomplished to date, the design of material handling and logistics systems
remains an art as well as a science.
Regardless of whether it is people, conveyors, lift trucks, robots, guided vehicles,
laser scanners, storage/retrieval machines, carousels, voice encoding, machine
vision, automatic palletizers, or other methods that are appropriate, selecting the
right methods for moving, storing, and controlling material is vital. It is important that
the selection decision be made after consideration is given to the requirements for
amount, material, place, time, condition, sequence, orientation, and cost.
Too often, material handling method decisions are either made without knowing
the real requirements, or are just allowed to happen. It is critical that the material
handling system be requirements-driven, rather than solution-driven. Seldom does
force-fitting a solution on an incompatible set of requirements result in anything but
dissatisfaction.
Providing the right amount ofm aterial has become particularly important, due to
the emphasis on inventory reduction andjust-in-time manufacturing. Many situations
exist in manufacturing and distribution in which the wrong amount of material is
moved, stored, and/or controlled. Particularly prevalent is the mismatch of issue
quantities and stocking quantities. A typical example is the issuance of parts in
multiples of ten, when they are stocked in cartons containing multiples of a dozen.
Many firms would realize substantial reductions in inventories by standardizing issue
quantities and stocking quantities.
The principle mistakes made in order picking are picking the wrong quantities and
picking the wrong merchandise. Not only must the right amount be provided, but also
it must be the right material. To facilitate correct item selection, labels are used on
cartons and containers. Automatic identification systems have become popular due
to their accuracy and speed in entering data into a control system. One of the most
important features of automatic identification systems is the ability to verify that the
right material is being picked.
Too frequently, material is put in the wrong place. Considerable amounts oft ime
are often consumed by personnel looking for material that has been misplaced. It is
important to have clearly identified locations for materials, whether in storage, in
transit, or in the process of being received, inspected, or shipped. Knowing the
location of material is just as critical to an efficient material handling system as
knowing the amount.
Providing material at the right time is another essential ingredient of a well
designed material handling and logistics system. The use ofj ust-in-time has reduced
the measurement system for time from days, weeks, and months to seconds, minutes,
and hours. Rather than measuring inventories in terms ofd ays, at the best firms it is
being measured in terms of hours. Because of the dependence of all "downstream"
elements on "upstream" performance, it has become extremely critical that the
material handling system be timely. For many firms, if material cannot be delivered
on time, it is better not delivered at all: being late is unacceptable!
The condition of material when it arrives at it point of use is highly dependent on
the quality of the handling system. Material handling is a major (if not the major)
contributor to damaged material. As a result, the methods used to move, store, and
control material must be selected carefully to minimize the potentialfor damaging the
material.
The earliest efforts to improve the efficiency of human activity resulted in the
advice to evaluate opportunities to eliminate, combine, simplify, and change se
quence! The sequence used to perform material handling and logistics operations can
likewise have a major impact on the efficiency and effectiveness of the activity.
Although it might appear redundant to focus on sequencing the delivery of material,
since the timing of delivery will take care of some of the sequencing aspects, it is
separately identified in order to ensure that consideration is given to the sequence of
material handling events. Few scheduling and sequencing algorithms used for
production planning incorporate material handling considerations. As a result, large
queues and buffers often occur.
Too frequently, little consideration is given to the orientation or position of
material. As a result, a high percentage of a person's time at a workstation is
consumed re-orienting or re-positioning material for the next operation. A number
off irms are investigating the use of robots with machine vision to perform picking
operations. The primary goal is to overcome the random orientation ofp arts. Before
investing large amounts of money to develop a means of coping with random
orientation, one should first attempt to maintain order. Two options are available
relative to the orientation of material: retain orientation or regain orientation.
Orientation is expensive to regain whether by the use of vibratory bowl feeders,
guides, or people; orientation can often be retained easily by the use offixtures and
packaging. Rather than automatically conclude that either option is the most
economical, it is recommended that careful attention be given to the cost ofr egaining
vs. the cost of retaining the orientation of material.
The cost ofm oving, storing and controlling material should be consideredfrom a
systems perspective, rather than in isolation. The objective in using material handling
is to reduce overall cost, not reduce the cost of performing the material handling
activity. What is the right cost of material handling? The answer depends on the
material characteristics and flow requirements. For some firms, material handling
may properly be the largest component of cost; for others it should be negligible.
During the past century, material handling and logistics have evolvedfromfirst
generation to fifth-generation approaches. The five generations are manual, me
chanical, automated, integrated, and intelligent material handling and logistics.
Today, all five generations simultaneously exist to some degree in practically all
organizations. However, considerable investments are being made in the develop
ment of intelligent systems.
The purpose of this series of books is to provide a contemporary collection of
papers that contribute to an increased understanding of the status of intelligent
material handling and logistics. Both artificial and natural intelligence are essential;
likewise, both the design and operation of material handling and logistics systems
must be performed more intelligently. Leading-edge research results and technologi
calforecasts allow those who are designing future-generation material handling and
logistics systems to anticipate advances in technology.
The first volume is organized into five sections. The first three sections treat three
classes of technologies that have found increased application in material handling
and logistics; guided vehicles, robots, and storage and retrieval equipment. Design,
control, and application oft hese technologies, as well as anticipatedfuture develop
ments, are addressed. Current limitations of the technologies are reviewed. Ernest
L. Hall provides an assessment ofm achine vision; William T. Rhodes provides insight
into the potential computing speeds that will be available for automated technologies
when optical computing becomes available and affordable. In the first volume, we
focus especially on advances in manufacturing. Due to its emergence and importance,
flexible manufacturing systems is the subject of Section Four. Design, control, and
operating aspects off lexible manufacturing are addressed in the papers provided.
This section includes chapters on simulation and queueing networks showing their
contribution to the design of manufacturing systems.
The volume concludes with a section on logistics. In the section, a single paper
focuses on the classical linehaul-backhaul problem. It provides a simple, but
powerful, method of solving this complex problem.
In this first volume, all papers were selected from among those presented in a
sequence ofr esearch forums organized by the Material Handling Research Center at
the Georgia Institute of Technology in Atlanta, GA (USA). Subsequent volumes will
draw from a variety of sources, including specially commissioned papers.
Dr. Ira W. Pence, Jr. Dr. John A. White
CONTENTS
SECTION ONE: GUIDED VEmCLE TECHNOLOGY
Guided Vehicle Technology: From Automated to Autonomous.............. 3
Larry E. Banta
The Design and Construction of Three Autonomous Vehicles................. 15
Kevin J. Dowling
Evaluation of Heuristic Control Strategies for AGVs Under
Varying Demand Arrival Patterns.............................................................. 35
Russell E. King. ThomJ. Hodgson. Steve K. Monteith
Towards a Free-Roving Vision-Guided AGV........................................... 41
Madeline HE. Larcombe
SECTION TWO: ROBOT TECHNOLOGY
Algorithms and Architectures for Machine Vision.................................... 59
Ernest L. Hall. Juha Roning
Increasing the Speed of Computers Using Optics...................................... 75
William T. Rhodes
Control of High-Speed Material Handling Manipulators.......................... 85
Stephen A. Dickerson
Experiments on the Control of a Satellite Manipulator............................. 93
Harold L. Alexander. Robert H. Cannon. Jr.
SECTION THREE: AUTOMATED STORAGE AND
RETRIEVAL TECHNOLOGY
Control Design Issues for Material Handling Systems.............................. 109
Stephen L. Parsley
The Automation of Material Handling System's Control Software.......... 121
George K. Hutchinson. A. T. Clementson
The Analysis of AS/RS Performance......................................................... 133
Ernest Koenigsberg
An Empirical Evaluation of a General Purpose Automated Order
Accumulation and Sortation System Used in Batch Picking..................... 151
Yavuz A. Bozer. Gunter P. Sharp
SECTION FOUR: MODELING TECHNOLOGY
Simulating Material Handling Systems..................................................... 181
C. Dennis Pegden
Networks of Queues with Blocking and Load Balancing.......................... 199
Ke-Tsai Edward Chin. Richard F. Serfozo
Manufacturing Systems Modelling: Its Role and Current Issues.............. 209
RajanSuri
Modeling Flexible Manufacturing Systems Using Product-Form
Queueing Networks.................................................................................... 223
DavidD. Yao
Validation of Manufacturing System Models............................................ 237
John A. Buzacott
SECTION FIVE: FLEXIBLE MANUFACTURING
Real-Time Adaptive Scheduling in Flexible Manufacturing Systems....... 249
John R. Birge
Real-Time Optimization in the Automated Manufacturing
Research Facility........................................................................................ 257
Wayne J. Davis. Richard H. F. Jackson. Albert T. Jones
Machine Configuration for Flexible Assembly Systems........................... 275
Christopher B. Lofgren
Design and Operating Issues in Flexible Manufacturing........................... 281
Kathryn E. Stecke
SECTION SIX: TRANSPORTATION
Linehaul-Backhaul: Solutions with Spaceftlling Curves.......................... 303
Charlotte (Horsley) Jacobs-Blecha. Marc Goetschalckx
SECTION ONE
GUIDED VEHICLE TECHNOLOGY
As aflexible computer-controlledfactory-wide transporter, the AGV has become a
popular topic. Like all new technologies, it has had its successes and failures.
Certainly the AGV is not the solution to all of our current material handling needs.
However, because its inherent flexibility fits so well with current trends in manufac
turing, it is likely to become an increasingly appropriate choice.
To use the flexibility of the AGV requires an understanding of the issues in
scheduling and controlling a guided vehicle . Fortunately these subjects have recently
become ofi nterest to the research community. The four chapters in this section, taken
together, give an excellent overview of both the general state-of-the-art, and some
intriguing specifics.
The first two chapters address the fundamental questions that arise in material
handling automation. First, how can we plan or schedule material movement in a
dynamic way with a minimum of human intervention. Second, once we can develop
appropriate plans, how can we reliably move the material.
The King, Hodgson, and Monteith chapter reviews the alternatives for planning
AGV motions. They provide a good reference to various heuristics. (The true
optimal combinatorial problem is beyond current practicality.) A particular heu
ristic, RULE, is examined in detail with simulation.
The Banta chapter reviews the range ofa lternativesfor actually making the moves,
i.e., the actual automatic guidance. He takes usfrom the conventional wire or stripe
following technology, through self-guided (where we still structure the plant for
AGVs), to the autonomous, where he considers the possibility of guidance without
special arrangements for the AGVs in the as-built plant environment.
The last two chapters deal with particular technologies useful infree-ranging and
autonomous vehicles. Dowling reviews three successive research vehicles that have
been built and tested at Carnegie-Mellon. The last two of these are aimed primarily
at outdoor, rather unstructured, environments. (Outdoor application of AGVs is
probably one that industry needs to consider more strongly.)
Larcombe discusses a relatively simple, yet effective, vision approach to guiding
vehicles where some structure is provided in terms of visual clues.
Dr. Stephen 1. Dickerson
