Active Control of Noise and Vibration, Second Edition

1559 Pages·2012·28.808 MB·English

by  Colin Hansen, Scott Snyder, Xiaojun Qiu, Laura Brooks, Danielle Moreau

Active Control of
Noise and Vibration
S e C o N d e d i t i o N
V o l u m e I
© 2012 by Taylor & Francis Group, LLC
K15995_FM.indd 1 9/25/12 9:41 AM
Active Control of
Noise and Vibration
S e C o N d e d i t i o N
V o l u m e I
Colin Hansen Scott Snyder Xiaojun Qiu
n n
Laura Brooks Danielle Moreau
n

Boca Raton London New York
CRC Press is an imprint of the
Taylor & Francis Group, an informa business
© 2012 by Taylor & Francis Group, LLC
K15995_FM.indd 3 9/25/12 9:41 AM
Active Control of
Noise and Vibration
S e C o N d e d i t i o N
V o l u m e I I
Colin Hansen Scott Snyder Xiaojun Qiu
n n
Laura Brooks Danielle Moreau
n

Boca Raton London New York
CRC Press is an imprint of the
Taylor & Francis Group, an informa business
© 2012 by Taylor & Francis Group, LLC
K15996_FM.indd 3 9/25/12 10:10 AM
CRC Press
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© 2012 by Taylor & Francis Group, LLC
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This book is dedicated
to
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Gillian
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Kristy
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© 2012 by Taylor & Francis Group, LLC
xvii
PREFACE TO FIRST EDITION
Active control of sound and vibration is a relatively new and fast growing field of
research and application. The numbers of papers published on the subject have been more
than doubling every year for the past ten years and each year more researchers are
becoming involved in this fascinating subject. Because of this rapid growth and
continuing new developments, it is difficult for any book to claim to cover the subject
completely. However, in this book we have attempted to include the most recent
theoretical and practical developments, while at the same time devoting considerable
space to fundamental principles which will not become outdated with time. We have also
devoted considerable space to explaining how active control systems may be designed and
implemented in practice and the practical pitfalls which one must avoid to ensure a
reliable and stable system.
We have treated the active control of noise and the active control of vibration in a
unified way, even though later on in the book some noise and vibration control topics are
treated separately. The reason for the unified treatment is that it is becoming increasingly
difficult to keep the two disciplines separate, as one depends so much on the other. For
example, the treatment of the active control of sound radiated by vibrating structures
would be incomplete if either active control of the radiated acoustic field or active control
of the structural vibration were omitted. Thus, in the first part of the book, which is
concerned entirely with fundamental concepts of relevance to active noise and vibration
control, an attempt has been made to combine the two subjects so that it can be seen how
they are related and how they share many common concepts.
One interesting topic which we have omitted from this book is a discussion of
patents. Not only is the subject a large one (with hundreds of patents already granted), it
is rapidly growing and it is difficult to do justice to it in a book of this type. One gem of
wisdom which we would like to share with our readers is that some of the patent holders
are only too willing to sue for patent infringement, even though it can be shown that prior
knowledge existed before many of the patents. Thus, any company preparing to market

any products containing active noise or vibration control should be prepared to fight a
legal battle for their right to do so unless they have obtained a licence to use the
technology from the patent owners. So far, it seems that lawyers and judges have made
more money from active control than any engineering company and they do not even own
any patents! It is also of interest to ponder upon the number of patents which are granted
that closely describe an aspect of active noise and vibration control which has been
patented previously. All we can do here is try to appeal to some sense of reason as the
results of too much litigation of this type will stifle research, slow down new product
development and create a wealthy legal profession, all of which we would be better off
without.
© 2012 by Taylor & Francis Group, LLC
xix
PREFACE TO SECOND EDITION
Over the fourteen years since publication of the first edition, considerable progress has
been made in the development and application of ANC systems, particularly in the
propeller aircraft industry. Inroads have also been made in the automotive industry with
several vehicles boasting ANC systems but none providing any performance data. In fact,
it is very difficult to find performance data for any commercial systems. The development
of a universal ANC system that can be installed and operated by non-expert personnel in a
range of applications remains an elusive goal. There is no doubt that this goal will be
achieved some day but we may need even more processing power than is currently
available in DSP technology to enable this to happen. In parallel, we will also need the
investment of considerable funds to support the labour needed for this development.
The intention of this book is the same as the first edition: that is, to include the most
recent theoretical and practical developments, while at the same time devoting
considerable space to fundamental principles that will not become outdated with time.
Thus, much of the book is similar to the first edition but a considerable amount of new
material has been added to reflect the advances that have been made in algorithms, DSP
hardware and applications.
The Chapter 1 overview has been updated to reflect the current state of the art at the
time of writing. The fundamentals material in Chapter 2 is largely unchanged, although
the section on acoustic intensity has been updated. The spectral analysis material of
Chapter 3 has been updated in a minor way, and the modal analysis material of Chapter 4
has been updated in line with advances in this field. Chapter 5 is largely unchanged but
Chapter 6 has a considerable number of additions, including multi-channel waveform
synthesis, nine variations of the FXLMS algorithm for various applications, new methods
for determining the cancellation path impulse response or transfer function, a more
comprehensive discussion of adaptive filtering in the frequency domain, the lattice form
of the IIR filter, a wider ranging discussion of the use of IIR filters, and performance
estimation procedures for a particular arrangement of control sources and error sensors.
Chapter 7 now includes some practical application examples, including active/passive
mufflers and a discussion of practical problems that are associated with industrial

installations. Chapter 8 now includes material on the use of a sound intensity cost
function, model reference control, sensing radiation modes, modal filtering and a
comparison of the effectiveness of various error sensing strategies. Chapter 9 includes
new material on feedback control of sound transmission into enclosed spaces with
particular application to launch vehicles and material on the use of active vibration control
to reduce sound transmission into flexible-walled enclosures. Chapter 10 has been slightly
updated but remains largely unchanged. Chapter 11 includes a considerable amount of
new material on model uncertainty, experimental determination of the system model,
optimisation of the truncated model, collocated actuators and sensors, biologically
inspired control and a discussion of centralised versus de-centralised control. Chapter 12
has been updated with new material and Chapter 13 has been completely rewritten.
Chapter 14 has been considerably expanded to include new material on parametric array
loudspeakers, turbulence filtering and virtual sensing. The smart structures part of
Chapter 15 has been considerably expanded to reflect the considerable amount of work
that has been published recently in this area.
© 2012 by Taylor & Francis Group, LLC
xxi
AUTHOR BIOGRAPHIES
Colin H Hansen
Colin Hansen is professor emeritus in the School of Mechanical Engineering at the
University of Adelaide in Australia. He has been researching and consulting in active
noise and vibration control since joining the academic staff in the School of Mechanical
Engineering at the University of Adelaide in 1987, following seven years as a noise and
vibration consultant in the United States (with Bolt Beranek and Newman) and Australia.
He established the ANVC group at the University of Adelaide in 1987 and led the group
until his retirement from academe at the end of 2011. The group is internationally
recognised for its extensive contributions to the advancement of scientific knowledge in
many aspects of active noise and vibration control. Hansen's research has led to him
authoring or co-authoring over 250 papers on active noise and vibration control in
international journals and conference proceedings, the co-development of a commercial
multi-channel ANC system that has users from six different countries and with the help of
his colleagues, the installation of two successful industrial ANC systems that involved the
control of higher-order mode propagation in ducts under extreme environmental
conditions.
In addition to his work on active noise and vibration control, Hansen has authored or
co-authored 9 other books, edited two books and contributed seven chapters to various
books on noise and vibration control. He co-developed a suite of noise control software
(ENC) based on his Engineering Noise Control textbook, and this has more than 100
users worldwide.
Hansen served for two years (2000–2002) as president of the International Institute
of Acoustics and Vibration (IIAV) and since 1997 has also served in a number of other
executive positions in the organisation. In 2012 he was made the 15th honorary fellow of
IIAV in recognition of his “outstanding contributions to scientific knowledge in acoustics,
noise and vibration” and in 2009 he was awarded the Rayleigh Medal by the British
Institute of Acoustics for “outstanding contributions to acoustics”. He is a fellow of the
Australian Acoustical Society and Engineers Australia and is a chartered professional

engineer. He was also head of the School of Mechanical Engineering at the University of
Adelaide for the fourteen years prior to 2010.
Scott D Snyder
As the pro vice-chancellor for strategy and planning, Scott Snyder coordinates and is
responsible for strategic initiatives on behalf of Charles Darwin University (CDU). His
role is to oversee the implementation of the university's strategic plan, development and
direction of major projects, initiatives and reviews, management of activities supporting
expansion of university student load, and response to major stakeholders, including
government.
Prior to his position at CDU, Snyder was head of the IT Department at the University
of Adelaide. However, his PhD was in the area of active noise and vibration control and
he spent a number of years following his PhD undertaking further research on ANVC in
© 2012 by Taylor & Francis Group, LLC
xxii Active Control of Noise and Vibration
Japan and at the University of Adelaide after which he was appointed to the academic
staff in the School of Mechanical Engineering at the University of Adelaide. As an
academic staff member, Snyder supervised a number of research projects and PhD
students in the area of active noise and vibration control and co-authored the first edition
of this book with Colin Hansen. He also co-developed a commercial multi-channel ANC
system and wrote a basic active noise control “primer” to assist users of the ANC system.
Xiaojun Qiu
Xiaojun Qiu graduated in electronics from Peking University, China, in 1989 and
received his PhD degree from Nanjing University, China, in 1995 for a dissertation on
active noise control. He worked with Professor Hansen in the School of Mechanical
Engineering at the University of Adelaide, Australia, as a research fellow from 1997 to
2002. He has been working in the Institute of Acoustics, Nanjing University, as a
professor in acoustics and signal processing since 2002 and now is the head of the
Institute. He visited Germany as a Humboldt Research Fellow in 2008. His main research
areas include noise and vibration control, room acoustics, electro-acoustics and audio
signal processing. He is a member of the Audio Engineering Society and the International
Institute of Acoustics and Vibration. He has authored and co-authored 2 books, more than
250 technical papers and holds more than 70 patents on audio acoustics and audio signal
processing.
Laura A Brooks
Laura Brooks was awarded a bachelor of mechanical engineering with first class honours
in 2003 and a PhD in mechanical engineering in 2008, both from the University of
Adelaide. She was selected by Engineers Australia for inclusion in the list of Australia's
Most Inspiring Young Engineers in 2005 and was awarded the 2006 Fulbright
Postgraduate Award in Engineering, enabling her to spend two years as a visiting scholar
at the Scripps Institution of Oceanography in the United States. From 2008 through 2009
Laura worked as a postdoctoral fellow at Victoria University in Wellington, New
Zealand. She was a lecturer in the School of Mechanical Engineering at the University of
Adelaide from 2010 through 2012, and currently retains an adjunct position with the
university. Her research interests span a broad range of fields including aeroacoustics,
ocean acoustics, seismic noise, vibrations, active control, signal processing and
engineering education.
Danielle J Moreau
Danielle Moreau is a postdoctoral research associate at the School of Mechanical
Engineering at the University of Adelaide. She completed her PhD on virtual sensing
methods for active noise control at the University of Adelaide in 2010 and received a
University Postdoctoral Research Medal for her PhD research. In her current role as
research associate, the focus of Dr Moreau’s work is on the understanding and control of
flow-induced noise. Dr Moreau has over 20 publications in leading outlets and has also
© 2012 by Taylor & Francis Group, LLC
xxiii
been invited to give seminars to research groups at Tokyo Metropolitan University
(Tokyo, Japan), Stanford University (California, United States) and the National Energy
Renewable Energy Laboratory (Colorado, United States).

© 2012 by Taylor & Francis Group, LLC