Advances in Industrial Control
Other titles published in this series:
Digital Controller Implementation Modelling and Control of Mini-Flying
and Fragility Machines
Robert S.H. Istepanian and James F. Pedro Castillo, Rogelio Lozano and
Whidborne (Eds.) Alejandro Dzul
Optimisation of Industrial Processes
Ship Motion Control
at Supervisory Level
Tristan Perez
Doris Sáez, Aldo Cipriano and Andrzej W.
Ordys Hard Disk Drive Servo Systems (2nd Ed.)
Ben M. Chen, Tong H. Lee, Kemao Peng
Robust Control of Diesel Ship Propulsion
and Venkatakrishnan Venkataramanan
Nikolaos Xiros
Measurement, Control, and
Hydraulic Servo-systems
Communication Using IEEE 1588
Mohieddine Jelali and Andreas Kroll
John C. Eidson
Model-based Fault Diagnosis in Dynamic
Systems Using Identification Techniques Piezoelectric Transducers for Vibration
Silvio Simani, Cesare Fantuzzi and Ron J. Control and Damping
Patton S.O. Reza Moheimani and Andrew J.
Fleming
Strategies for Feedback Linearisation
Freddy Garces, Victor M. Becerra,
Manufacturing Systems Control Design
Chandrasekhar Kambhampati and
Stjepan Bogdan, Frank L. Lewis, Zdenko
Kevin Warwick
Kova%0Å„ić and José Mireles Jr.
Robust Autonomous Guidance
Windup in Control
Alberto Isidori, Lorenzo Marconi and
Peter Hippe
Andrea Serrani
Nonlinear H2/H" Constrained Feedback
Dynamic Modelling of Gas Turbines
Control
Gennady G. Kulikov and Haydn A.
Murad Abu-Khalaf, Jie Huang and
Thompson (Eds.)
Frank L. Lewis
Control of Fuel Cell Power Systems
Practical Grey-box Process Identification
Jay T. Pukrushpan, Anna G. Stefanopoulou
and Huei Peng Torsten Bohlin
Fuzzy Logic, Identification and Predictive
Control of Traffic Systems in Buildings
Control
Sandor Markon, Hajime Kita, Hiroshi Kise
Jairo Espinosa, Joos Vandewalle and
and Thomas Bartz-Beielstein
Vincent Wertz
Wind Turbine Control Systems
Optimal Real-time Control of Sewer
Fernando D. Bianchi, Hernán De Battista
Networks
and Ricardo J. Mantz
Magdalene Marinaki and Markos
Papageorgiou
Advanced Fuzzy Logic Technologies in
Industrial Applications
Process Modelling for Control
Ying Bai, Hanqi Zhuang and Dali Wang
Benoît Codrons
(Eds.)
Computational Intelligence in Time Series
Practical PID Control
Forecasting
Antonio Visioli
Ajoy K. Palit and Dobrivoje Popovic
Tan Kok Kiong " Lee Tong Heng " Huang Sunan
Precision Motion Control
Design and Implementation
Second Edition
123
Tan Kok Kiong, PhD
Lee Tong Heng, PhD
Huang Sunan, PhD
Department of Electrical and Computer Engineering
National University of Singapore
4 Engineering Drive 3
Singapore 117576
Singapore
ISBN 978-1-84800-020-9 e-ISBN 978-1-84800-021-6
DOI 10.1007/978-1-84800-021-6
Advances in Industrial Control series ISSN 1430-9491
British Library Cataloguing in Publication Data
Tan, Kok Kiong, 1967-
Precision motion control : design and implementation. - 2nd
ed. - (Advances in industrial control)
1. Motion control devices 2. Automatic control
I. Title II. Lee, Tong Heng, 1958- III. Huang, Sunan, 1962-
629.8
ISBN-13: 9781848000209
Library of Congress Control Number: 2007939805
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Advances in Industrial Control
Series Editors
Professor Michael J. Grimble, Professor of Industrial Systems and Director
Professor Michael A. Johnson, Professor (Emeritus) of Control Systems and Deputy Director
Industrial Control Centre
Department of Electronic and Electrical Engineering
University of Strathclyde
Graham Hills Building
50 George Street
Glasgow G1 1QE
United Kingdom
Series Advisory Board
Professor E.F. Camacho
Escuela Superior de Ingenieros
Universidad de Sevilla
Camino de los Descubrimientos s/n
41092 Sevilla
Spain
Professor S. Engell
Lehrstuhl für Anlagensteuerungstechnik
Fachbereich Chemietechnik
Universität Dortmund
44221 Dortmund
Germany
Professor G. Goodwin
Department of Electrical and Computer Engineering
The University of Newcastle
Callaghan
NSW 2308
Australia
Professor T.J. Harris
Department of Chemical Engineering
Queen s University
Kingston, Ontario
K7L 3N6
Canada
Professor T.H. Lee
Department of Electrical Engineering
National University of Singapore
4 Engineering Drive 3
Singapore 117576
Professor Emeritus O.P. Malik
Department of Electrical and Computer Engineering
University of Calgary
2500, University Drive, NW
Calgary
Alberta
T2N 1N4
Canada
Professor K.-F. Man
Electronic Engineering Department
City University of Hong Kong
Tat Chee Avenue
Kowloon
Hong Kong
Professor G. Olsson
Department of Industrial Electrical Engineering and Automation
Lund Institute of Technology
Box 118
S-221 00 Lund
Sweden
Professor A. Ray
Pennsylvania State University
Department of Mechanical Engineering
0329 Reber Building
University Park
PA 16802
USA
Professor D.E. Seborg
Chemical Engineering
3335 Engineering II
University of California Santa Barbara
Santa Barbara
CA 93106
USA
Doctor K.K. Tan
Department of Electrical Engineering
National University of Singapore
4 Engineering Drive 3
Singapore 117576
Professor Ikuo Yamamoto
The University of Kitakyushu
Department of Mechanical Systems and Environmental Engineering
Faculty of Environmental Engineering
1-1, Hibikino,Wakamatsu-ku, Kitakyushu, Fukuoka, 808-0135
Japan
Series Editors Foreword
The series Advances in Industrial Control aims to report and encourage technology
transfer in control engineering. The rapid development of control technology has
an impact on all areas of the control discipline. New theory, new controllers,
actuators, sensors, new industrial processes, computer methods, new applications,
new philosophies& , new challenges. Much of this development work resides in
industrial reports, feasibility study papers and the reports of advanced collaborative
projects. The series offers an opportunity for researchers to present an extended
exposition of such new work in all aspects of industrial control for wider and rapid
dissemination.
A striking development in the Advances in Industrial Control series that has
occurred over the last few years have been the appearance in the series of highly
authoritative volumes that are more comprehensive than the usual monograph for a
particular technical area in industrial control. The Editors believe these volumes
have set new standards for the presentation of knowledge and industrial control
research in their specific fields. Typical examples are: Hydraulic Servo-systems by
Mohieddine Jelali and Andreas Kroll, Control of Fuel Cell Power Systems by Jay
Pukrushpan, Anna Stephanopoulou and Huei Peng, Hard Disk Drive Servo Systems
(now in its second edition) by Ben Chen, Tong Heng Lee, Kemao Peng and
Venkatakrishnan Venkataramanan, Piezoelectric Transducers for Vibration Control
and Damping by Reza Moheimani and Andrew Fleming, and finally Wind Turbine
Control Systems by Fernando Bianchi, Hernán De Battista and Ricardo Mantz.
These and other volumes like them in the series all seemed to capture the  spirit of
the age in the field of individual control in the new millennium. To these volumes,
the Editors are very pleased to add a second edition of Precision Motion Control
by Kok Kiong Tan, Tong Heng Lee and Sunan Huang; this is a revision of a
volume that was first published in the Advances in Industrial Control series in
2001.
The new volume presents a revised and systematic coverage of many of the
theoretical and practical aspects of precision motion control. A strong feature of
the volume is its presentation and integration of industrial control methods with
new advanced control solutions in this field. This is often illustrated by presenting
experimental results that span the full range of hardware implementations, from
viii Series Editors Foreword
classical control through to new control solutions advanced by the authors. The
authors often approach the control engineering problems by starting with standard
industrial control solutions (usually PID) and go on to show how system
performance can be enhanced by the addition of advanced control features. In
some cases completely new advanced control approaches are proposed. Models,
too, are sufficiently complex to capture important nonlinear system effects like
friction and ripple.
An example of the authors approach can be found in their treatment of the
control for permanent magnet linear motors. The system model is basically linear
in structure with additional nonlinear loops to represent the debilitating physical
effects of friction and force ripple. The control system design begins from classical
PID control which is then augmented by feed-forward control and adaptive radial-
basis-function (RBF) compensation to achieve enhanced system performance in
the presence of nonlinear disturbances.
As well as being a compendium of the technology used in state-of-the-art
precision motion control  and indeed there are many excellent descriptions of
equipment, hardware, software and techniques used in this field  the volume has
interesting reports of new approaches to real problems in precision motion control.
Three examples illustrate the types of approach taken. In Chapter 3, new
applications are described for the relay experiment; in this particular case, it is used
to identify a friction model to enhance the control design. In Chapter 4, the co-
ordinated control of a gantry system is investigated, and the performance of PID
compared with that of an adaptive controller; however, real performance
enhancements are shown to accrue to those control strategies that overcome the
multivariable interactions that are present in the system. Finally, Chapter 7 reports
on a mechatronics approach to control design where the structural design of the
machine is seamlessly integrated with the control system design.
This second edition of Precision Motion Control is likely to become a source
book for a very wide range of readers. It has industrial perspectives, current state-
of-the-art hardware descriptions, academic perspectives and advanced control
system solutions often explained from initial conception right through to results
from laboratory rigs and prototype tests. Thus, the volume makes a very welcome
and appropriate contribution to the Advances in Industrial Control series.
Industrial Control Centre M.J. Grimble
Glasgow M.A. Johnson
Scotland, UK
2007
Preface
Precision manufacturing has been steadily gathering momentum and attention
over the last century in terms of research, development, and application to
product innovation. The driving force in this development appears to arise
from requirements for much higher performance of products, higher reliability,
longer life, lower cost, and miniaturisation. This development is also widely
known as precision engineering and, today, it can be generally defined as
manufacturing to tolerances which are better than one part in 105.
The historical roots of precision engineering are arguably in the field of
horology, the development of chronometers, watches and optics, e.g., the man-
ufacture of mirrors and lenses for telescopes and microscopes. Major contri-
butions were made to the development of high-precision machine tools and
instruments in the late 1800s and early 1900s by ruling engines for the man-
ufacture of scales, reticules and spectrographic diffraction gratings. Today,
ultra-precision machine tools under computer control can position the tool
relative to the workpiece to a resolution and positioning accuracy in an order
better than micrometers. It must be noted that achievable  machining accu-
racy includes the use of not only machine tools and abrasive techniques, but
also energy beam processes such as ion beam and electron beam machining, as
well as scanning probe systems for surface measurement and pick-and-place
types of manipulation.
In the new millenium, ultra-precision manufacture is poised to progress
further and to enter the nanometer scale regime (nanotechnology). Increasing
packing density on integrated circuits and sustained breakthrough in min-
imum feature dimensions of semiconductors set the pace in the electronics
industry. Emerging technologies such as Micro-electro-mechanical Systems
(MEMS), otherwise known as Micro-systems Technology (MST) in Europe
further expands the scope of miniaturisation and integration of electrical and
mechanical components.
This book is focused on the enabling technologies in the realisation of pre-
cision motion positioning systems. It is a compilation of the major results
and publications from projects set out to develop state-of-the-art high-speed,
x Preface
ultra-precision robotic systems. A comprehensive and thorough treatment of
the subject matter is provided in a manner amenable to a broad base of
readers, ranging from academics to practitioners, by providing detailed ex-
perimental verifications of the developed materials.
The book begins with an introduction to precision engineering, and pro-
vides a brief survey of its development and applications. Chapter 2 addresses
the control system technology to achieve high-precision motion control in mo-
tion systems. Intelligent control schemes are presented which can yield high
performance in terms of tracking accuracy. These control schemes use different
combinations of advanced control theory and artificial intelligence according
to the information available and the nature of operations. These include an
adaptive control scheme, a composite control scheme comprising linear and
non-linear control components, an adaptive ripple compensation scheme, a
disturbance observer and compensation scheme, and a learning control strat-
egy. Experimental results are duly provided for comparison and verification of
the performance and improvement achievable over standard controllers. The
use of a high grade accelerometer in providing direct acceleration measure-
ments and an illustration of the possible enhancement in tracking performance
achievable with additional state feedback are clearly elaborated. While the
materials are applied to the subject matter, they are sufficiently generic to
interest general control specialists and practitioners.
Chapter 3 presents relay feedback configurations and techniques which
are suitable to produce nominal models for the motion systems, based on
sustained small amplitude oscillations induced in the closed-loop. In this way,
the control systems as presented in Chapter 2 can be automatically tuned and
commissioned, and yet satisfactory performance can be achieved. A variation
of the basic configuration to facilitate the automatic modelling of the frictional
effects is also given. These models can be used to commission feedforward and
feedback controllers, and they are also useful for the initialisation of adaptive
control. A scheme is provided for optimal features extraction from possibly
noisy relay oscillations.
Chapter 4 addresses a popular configuration of precision Cartesian robotic
systems, the moving gantry stage, which is frequently employed in wafer step-
pers and fine resolution assembly machines. Apart from individual servo track-
ing requirements, it is also necessary that the parallel servo systems move in
tandem to minimise the inter-axis offsets. Different control configurations are
presented and compared in terms of their performance. These include control
schemes used in existing industrial control systems, as well as more recent
developments.
Chapter 5 presents a comprehensive treatment of the topic of geometrical
error calibration and compensation. The sources of geometrical errors, the
calibration equipment used in their measurement, treatment and modelling
from the raw data set to the final compensation via the control system are
among the topics which will be delivered systematically in this chapter. Recent
and refreshing advances in geometrical calibration and compensation are also
Preface xi
presented in the chapter, which include the use of Artificial Intelligence (AI)
approaches in geometrical error modelling. Possible probabilistic approaches,
formulated to reduce the influence of random errors from affecting the sys-
tematic error compensation, are also presented in the chapter.
Chapter 6 addresses explicitly the measurement system. Precision motion
control can only be possible with precision motion measurements. Encoder
interpolation is a cost effective way to derive fine resolution position mea-
surements using only devices and instruments at moderate costs. Techniques
are presented to correct for imperfections in encoder signals and to derive
fractional resolution from the corrected signals to fulfil high-resolution re-
quirements in the input signals for the control system.
Chapter 7 will touch on the topic of vibration monitoring and control.
Three approaches are presented. The first focuses on a proper mechanical
design, based on the determinacy of machine structure, to reduce the me-
chanical vibration to a minimum. The second approach is based on the notch
filter and its application as part of the control system to suppress frequencies
which may excite undesirable mechanical resonance. An adaptive technique
based on Fast Fourier Transform (FFT) tracks the resonant frequency and
adapts the filter accordingly. The third approach uses a technique based on
sensor fusion to monitor and analyse the vibration of precision machines. A
DSP device is used to learn and capture the vibration signature of the ma-
chine under normal operational circumstances. When the machine deviates
from its normal operational condition, the device can detect the abnormality
and activates appropriate fault diagnostic and maintenance measures.
Finally, in Chapter 8, other important engineering aspects behind the con-
struction of a high-precision motion control system are discussed. These in-
clude the considerations behind selection of components, hardware architec-
ture, software development platform, user interface design, evaluation tests
which are crucial in determining the final success of the system, and digital
communication protocols.
This book provides extensive and up-to-date coverage of the methodology
and algorithms of precision motion control considered mainly in the context
of control engineering and soft computing.
Compared to the first edition, the new edition has incorporated a series of
modifications, updates and extensions. Some six years after publication of the
first edition, precision engineering has remained an important area in control
engineering and new results have emerged. The first edition has been updated
with new contents, including piezo actuator modelling and control (Chapter
2), adaptive co-ordinated control scheme (Chapter 4), parametric model for
interpolation (Chapter 6), mechanical design to minimise vibration (Chapter
7), and digital communication protocols (Chapter 8). The introductory chap-
ter has been substantially revised to reflect the state-of-the-art of precision
motion control.
This book would not be possible without the generous assistance of the
following colleagues and friends: Dr Lim Ser Yong, Mr Andi Sudjana, Mr
xii Preface
Teo Chek Sing, Dr Tang Kok Zuea, Dr Zhou Huixing and Mr Jiang Xi. The
authors would like to express their sincere appreciation of their kind assis-
tance provided in the writing of the book. They would also like to thank the
National University of Singapore (NUS) and Singapore Institute of Manufac-
turing Technology for co-funding the projects from which most of the infor-
mation and results reported in the book have originated. The authors also
acknowledge the kind permission from Hewlett Packard for the reproduction
of figures relating to laser measurement systems.
Finally, the authors would like to dedicate the book to our families for
their love and support.
Singapore, Kok Kiong Tan
May 2007 Tong Heng Lee
Sunan Huang
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Fields Requiring Precision Control . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1.1 Precision Engineering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1.2 Micromanufacturing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1.3 Biotechnology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.1.4 Nanotechnology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.2 Precision Machines and Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.3 Applications of Precision Motion Control Systems . . . . . . . . . . . 9
1.3.1 Semiconductor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.3.2 Magnetic and Optical Memory Manufacturing . . . . . . . . 9
1.3.3 Optical Manufacturing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.3.4 High-resolution Imaging. . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.3.5 Precision Metrology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
1.4 Scope of the Book . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2 Precision Tracking Motion Control . . . . . . . . . . . . . . . . . . . . . . . . 11
2.1 Piezoelectric Actuators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.1.1 Types of Piezoelectric Actuator Configuration . . . . . . . . 11
2.1.2 Mathematical Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.1.3 Adaptive Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.2 Permanent Magnet Linear Motors (PMLM) . . . . . . . . . . . . . . . . . 24
2.2.1 Types of PMLM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
2.2.2 Mathematical Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
2.2.3 Force Ripples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
2.2.4 Friction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
2.2.5 Composite Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
2.2.6 Control Enhancement with Accelerometers . . . . . . . . . . . 44
2.2.7 Ripple Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
2.2.8 Disturbance Observation and Cancellation. . . . . . . . . . . . 54
2.2.9 Robust Adaptive Control . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
2.2.10 Iterative Learning Control . . . . . . . . . . . . . . . . . . . . . . . . . . 72
xiv Contents
3 Automatic Tuning of Control Parameters . . . . . . . . . . . . . . . . . . 83
3.1 Relay Auto-tuning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
3.1.1 Relay with Delay. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
3.1.2 Two-channel Relay Tuning . . . . . . . . . . . . . . . . . . . . . . . . . 87
3.2 Friction Modelling Using Relay Feedback . . . . . . . . . . . . . . . . . . . 87
3.2.1 Friction Identification Method . . . . . . . . . . . . . . . . . . . . . . 88
3.2.2 Simulation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
3.2.3 Initialisation of Adaptive Control . . . . . . . . . . . . . . . . . . . . 92
3.3 Optimal Features Extraction from Relay Oscillations . . . . . . . . . 92
3.4 Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
4 Co-ordinated Motion Control of Gantry Systems . . . . . . . . . . 101
4.1 Co-ordinated Control Schemes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
4.1.1 Classical Master/Slave Approach . . . . . . . . . . . . . . . . . . . . 103
4.1.2 Set-point Co-ordinated Control . . . . . . . . . . . . . . . . . . . . . 104
4.1.3 Fully Co-ordinated Control . . . . . . . . . . . . . . . . . . . . . . . . . 105
4.2 Simulation Study. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
4.2.1 Control Task . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
4.2.2 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
4.3 Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
4.3.1 XY Table ConfigurationI . . . . . . . . . . . . . . . . . . . . . . . . . . 110
4.3.2 XY Table-Configuration II . . . . . . . . . . . . . . . . . . . . . . . . . . 112
4.4 Adaptive Co-ordinated Control Scheme . . . . . . . . . . . . . . . . . . . . 114
4.4.1 Dynamic Modelling of Gantry Stage . . . . . . . . . . . . . . . . . 116
4.4.2 Model-based Adaptive Control Design . . . . . . . . . . . . . . . 121
4.4.3 Stability Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
4.4.4 Software Simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
4.4.5 Implementation Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
5 Geometrical Error Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . 129
5.1 Overview of the Laser Measurement System . . . . . . . . . . . . . . . . 130
5.2 Components of the Laser Measurement System. . . . . . . . . . . . . . 131
5.2.1 Laser Head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
5.2.2 Interferometer and Reflector . . . . . . . . . . . . . . . . . . . . . . . . 133
5.2.3 Measurement Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
5.2.4 Measurement and Control Electronics . . . . . . . . . . . . . . . . 134
5.3 Overviewof Laser Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
5.3.1 Linear Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
5.3.2 Angular Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
5.3.3 Straightness Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . 136
5.3.4 Squareness Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
5.4 Roll Measurement Using a Level-sensitive Device . . . . . . . . . . . . 139
5.5 Accuracy Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
5.6 Factors Affecting Measurement Accuracy . . . . . . . . . . . . . . . . . . . 140
5.6.1 Linear Measurement Errors . . . . . . . . . . . . . . . . . . . . . . . . . 140
Contents xv
5.6.2 Angular Measurement Errors . . . . . . . . . . . . . . . . . . . . . . . 143
5.6.3 Straightness Measurement Errors . . . . . . . . . . . . . . . . . . . . 143
5.6.4 Environmental Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . 143
5.7 Overall Error Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
5.8 Look-up Table for Geometrical Errors . . . . . . . . . . . . . . . . . . . . . . 146
5.9 Parametric Model for Geometrical Errors . . . . . . . . . . . . . . . . . . . 148
5.9.1 Error Modelling with Radial Basis Functions . . . . . . . . . . 148
5.9.2 Parameter Error Approximations . . . . . . . . . . . . . . . . . . . . 149
5.9.3 Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
5.9.4 Error Modelling with Multi-layer Neural Networks . . . . . 156
5.10 Compensation of Machines with Random Errors . . . . . . . . . . . . . 161
5.10.1 Probabilistic Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . 162
5.10.2 Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
6 Electronic Interpolation Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
6.1 Heydemann Interpolation Method . . . . . . . . . . . . . . . . . . . . . . . . . 172
6.1.1 Interpolation Bounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174
6.1.2 Calibration and Compensation . . . . . . . . . . . . . . . . . . . . . . 175
6.2 Enhanced Interpolation Method . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
6.2.1 Principle of Enhanced Interpolation Method . . . . . . . . . . 176
6.2.2 Construction of a Look-up Table . . . . . . . . . . . . . . . . . . . . 177
6.2.3 Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
6.3 Parametric Model for Interpolation . . . . . . . . . . . . . . . . . . . . . . . . 184
6.3.1 Principles of Interpolation Approach. . . . . . . . . . . . . . . . . 185
6.3.2 Precompensation Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
6.3.3 Interpolation Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
6.3.4 Experimental Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
7 Vibration Monitoring and Control . . . . . . . . . . . . . . . . . . . . . . . . . 195
7.1 Mechanical Design to Minimise Vibration . . . . . . . . . . . . . . . . . . . 196
7.1.1 Stability and Static Determinacy of Machine Structures 196
7.1.2 Two-dimensional Structures . . . . . . . . . . . . . . . . . . . . . . . . 197
7.1.3 Three-dimensional Structures . . . . . . . . . . . . . . . . . . . . . . . 201
7.2 Adaptive Notch Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207
7.2.1 Fast Fourier Transform. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209
7.2.2 Simulation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209
7.2.3 Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209
7.3 Real-time Vibration Analyser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210
7.3.1 Learning Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212
7.3.2 Monitoring Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
7.3.3 Diagnostic Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217
7.3.4 Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218
7.3.5 Remote Monitoring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
7.3.6 Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225
xvi Contents
8 Other Engineering Aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
8.1 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232
8.2 Selection of Motors and Drives . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232
8.3 Selection of Encoders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232
8.4 Control Platform. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233
8.4.1 Hardware Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233
8.4.2 Software Development Platform. . . . . . . . . . . . . . . . . . . . . 236
8.4.3 User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
8.5 Accuracy Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
8.6 Digital Communication Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . 241
8.6.1 Fieldbus Protocol Stack . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
8.6.2 Common Fieldbuses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245
A Laser Calibration Optics, Accessories and Set-up . . . . . . . . . . 253
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271