Table Of ContentInternational Series on
MICROPROCESSOR-BASED AND
INTELLIGENT SYSTEMS ENGINEERING
VOLUME 23
Editor
Professor S. G. Tzafestas, National Technical University of Athens, Greece
Editorial Advisory Board
Professor C. S. Chen, Unilersity ofA kron, Ohio, U.S.A.
Professor T. Fokuda, Nagoya University, Japan
Professor F. Harashima, Uiliversity of Tokyo, Tokyo, Japan
Professor G. Schmidt, Technical University of Munich, Germany
Professor N. K. Sinha, Mc.Master University, Hamilton, Ontario, Canada
Professor D. Tabak, Georg" Mason University, Fairfax, Virginia, U.S.A.
Professor K. Valavanis, Un.\ ersity of Southern Louisiana, Lafayette, U.S.A.
The titles published in this sedes are listed at the end of this volume.
An Introduction to Fuzzy Logic Applications
An Introduction to
Fuzzy Logic Applications
by
JOHN HARRIS
National University of Science & Technology, Zimbabwe
....
,~
KLUWER ACADEMIC PUBLISHERS
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ISBN-13 :978-1-4020-0395-0 e-ISBN-I 3 :978-94-0 I 0-9042-1
DOl: 10.1007/978-94-010-9042-1
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To
William John Maxwell Duckworth
AN INTRODUCTION TO FUZZY LOGIC APPLICAn ONS.
List of Contents.
Preface.
Chapter 1. Comments and definitions. 1
1. 1 Classical logic basics. 1
1.2 Fuzzy logic. 2
1.2.l Fuzzy Venn diagrams and sets. 2
1.2.2 Universe of discourse. 3
1.2.3 Fuzzy set shapes. 4
1.2.4 Propositions. 5
1.2.5 The complementary FL set. 6
1.3 Knowledge engineering. 6
1.3. 1 Planning an integrated system. 6
1.3.2 Process selection. 7
1.3.3 Creating a FL system. 7
1.3.4 Integration of the FL system. 8
1.3.5 Validation of the integrated system. 8
1.4 Information and intelligence. 8
1.5 Notation. 9
PART 1. PROCESSES AND MATERIALS.
Chapter 2. Flow processes. 10
2.1 Level control. 10
2.2 Non-Newtonian flow. 15
2.3 FL Pipe flow design. 18
2.4 Transport of solids. 22
2.5 Mixing and dispersion. 27
Chapter 3. Thermal processes. 37
3.1 Non-flow processes. 38
3.2 Otto, Diesel and compound cycles. 41
3.3 Engine characteristics. 44
3.4 Thermo-flow processes. 46
3.5 Joule cycle. 48
3.6 Rankine cycle. 50
3.7 Heat exchangers 54
3.8 Heat transfer coefficient. 58
3.9 Solar collectors. 61
vii
Chapter 4. Materials technology. 66
4.1 Elastic bending. 67
4.2 Elastic instability. 72
4.3 Failure of an assembly. 76
4.4. Polymeric solids. 78
4.5. Press brake bending. 84
4.6. Forging. and extrusion 88
PART 2. SYSTEMS APPLICAn ONS.
Chapter 5. Automatic control. 92
5.1 Second-order linear systems. 94
5.2 Controllers. 95
5.3 Non-linear systems. 100
5.4 Fuzzy logic control (FLC). 101
5.5 Second-order non-linear processes. 106
5.6 More general parameters. 110
5.7 Look-up tables. 111
5.8 Hierarchical and adaptive FLC. 113
5.9 Hierarchical or distributed FLC 114
5.10 Autoadaptive FLC. 115
5.11 Artificial neural networks (ANN). 119
Chapter 6. Industrial engineering. 122
6.1 Process and equipment evaluation. 122
6.2 Resource assignment. 126
6.3 Multiple resources and demands. 126
6.4 Clustered resources and demands. 129
6.5 Clustering very fuzzy systems. 132
6.6 Work study. 136
6.6.1 Method study. 137
6.6.2 Work measurement. 142
6.7 Process planning. 148
6.8 Inventory control. 150
6.9 Batch processing. 152
6.10 Cyclic batches. 154
6.11 Fuzzy batch processing. 155
6.12 GANTT charts. 157
6.13 Process and product quality. 159
6.14 Benchmarking for quality. 160
6.15 Quality control. 164
6.16 Process quality control. 165
viii
Chapter 7. Management science. 170
7.1 Life-cycle costs. 170
7.2 Plant amortisation. 176
7.3 Tender adjudication. 178
7.4 Staff selection process. ISO
7.5 Supplier selection. IS4
7.6 Product and service quality. IS7
7.7 Future outcomes. 191
7.S Fuzzy actions and fuzzy states. 194
7.9 Updating probabilities. 196
Appendix: A guide to fuzzy logic. 198
Al Notation. 198
Al Defuzzification. 199
A3 Cartesian product. 199
A4 Composition. 200
AS Extension principle. 201
A6 Principal sets. 202
A 7 Grouping by similitude. 203
AS Grouping by composition. 206
A9 Inter-group relations. 20S
AI0 Multiple antecedents. 20S
A 11 Adjectival processes. 210
A12 Correlation metric .. 210
Further reading list. 212
IndeL 214
ix
Preface Xl
AN INTRODUCTION TO FUZZY LOGIC APPLICATIONS
PREFACE
This text has its origins in the notes prepared for a number of short courses on the
same topic, delivered to industriat and other professional groups. Although the
principles of fuzzy logic have been known for more than three decades, they are not at
present as widely understood or applied as their importance and value would justify.
This is partly explained by the fact that most literate and numerate people are educated
from an early age, whichever direction their education takes, to think in a classical
logic way, that is to think in terms of true or false propositions. But fuzzy logic
requires us to think in other terms than the quasi-classical logical, which is usually
employed with the aid of various linguistic devices when the issues are not clear-cut.
With fuzzy logic one is freed from this dependency, though it is natural to feel
apprehensive in contemplating such a step because we are used, by long training, to
continually striving to maintain intellectual rigour based upon classical logic principles.
Relief is however found in recognising that classical logic appears as a special case, so
it is not infact eclipsed by fuzzy logic, but for the real world it no longer occupies its
pre-eminent position. To clarify the meaning, it is emphasised that it is not the logic
itself that is fuzzy, but rather it is the information to which it is applied, the logic is
actually multi-valued and therefore more flexible than classical logic, hence providing a
language environment which is not antagonistic to fundamentally vague or imprecise
information.
Through sufficient practise, articulation of problems in fuzzy logic terms becomes
more familiar and quite natural. It is then recognised as a valuable tool in the
expression and solution of cases where uncertainty, vagueness or ambiguity exist and
where approximations are the norm. But now the approximations take on an entirely
different character. Such cases abound in every profession and are the normal
experience of everyone.
The text speaks to those engineers and others who may be interested in extending their
ideas beyond the more usual deterministic treatments which pervade most current
engineering education. These deterministic treatments are limited by their dependency
upon a classical logic foundation. It is unlikely that a single text will suffice to cater
for all needs and interests at the introductory level, but enough material is included to
provide literacy in fuzzy logic. The methods are presented in symbiotic relationship
with a cross-section of topics to found in current engineering education and point to
the possibilities of wider integration into existing studies. There are many solved
examples in the text to illustrate applications and to provide prototypes for further
developments. The material presented is not exhaustive either in the methods
illustrated or in the range of applications and it is hoped that the reader will feel
encouraged to explore further than the boundaries of this text.
Physical systems, be they intelligent or not, all ultimately depend upon natural
phenomena and the rules governing their behaviour. These rules are normally framed
in classical logic form, though this is fundamentally incompatible with ambiguity or
Preface
Xll
vagueness which is so often present to some degree in real problems. Part 1 of the text
therefore illustrates fuzzy logic treatments of a representative selection of
technological topics in processes and materials involving the processing of physical
information. The resulting physical deductions in the form of fuzzy sets can be
incorporated into knowledge based intelligent systems, as indicated in Chapter 1. Part
2 of the text takes up a systems perspective where physical phenomena are not explicit,
though physical systems operations and organisation are all affected to some degree by
fuzziness which has its origins in the underlying associated physical or psychological
phenomena. In this part qualitative information and appropriate value judgements are
incorporated, these are usually present in systems design, organisation and operations
management.
It is possible that the reader will already have some acquaintence with the topics
selected for fuzzy logic applications, as they often feature in whole or in part in many
engineering and technology study programmes and it is partly with this in mind that
they have been selected. For an introductory text it was deemed preferrable to present
familiar types of material in unfamiliar terms rather than unfamiliar material in
unfamiliar terms. Each chapter commences with introductory comments to recall some
of the main features of the topic and to set the context for the following treatments.
The text will be suited to engineering and technology courses, though some of the
material covered later in the text may also be suited to business and commerce
postgraduate programmes. Alternative fuzzy logic solutions to some problems are
shown in the text and it is possible to compare the richer solutions obtained through
the application of fuzzy logic with the current conventional treatments. If a
deterministic model to a problems is available it is possible to fuzzif)r it to
accommodate vague data, it is also possible construct a solution where no model is
available provided only that an opinion is held about the nature of the system relation
to a stimulus. The relationship may be refined by supervised or unsupervised learning
using training data.
Programmes of study are subject to rapid development and the esoteric subject of
today can become the commonplace of tomorrow. At the present time, the text would
be suitable for special topics in related undergraduate courses in the engineering
curriculum as well as for postgraduate courses Professional development short
courses for the industrial, commercial, utilities, government and military sectors can
also be based on material in the text.
There are relatively few texts available in this field at the present time in which
problems are solved in fuzzy logic form, though technological applications are
becoming increasingly available in the market for consumer products, especially where
there is a control function. It will be readily appreciated that the field of application
extends far beyond the material presented in this text, not only in the area of
technology, but also in such divers areas as law, medicine, economics and sociology,
all are likely to be increasingly influenced by the concepts and methods of fuzzy logic.
This is surely just the beginning of what will ultimately become its widespread use in
many fields, not only confined to technology.
