Active Sound and Vibration Control: theory and applications Volume 31 || Front Matter

Active Sound and Vibration Controltheory and applications

Edited by

Osman Tokhi and Sandor Veres

Control EnginEEring sEriEs 62

The Istitution of Electrical Engineers

Active Sound

and V

ibration Control

theory and applications

Downloaded 23 Aug 2012 to 128.59.62.83. Term of Use: http://digital-library.theiet.org/journals/doc/IEEDRL-home/info/subscriptions/terms.jsp

IEE CONTROL ENGINEERING SERIES 62

Series Editors: Professor D. P. AthertonProfessor G. W. IrwinProfessor S. Spurgeon

Active Soundand Vibration Controltheory and applications


Other volumes in print in this series:

Volume 2 Elevator traffic analysis, design and control G. C. Barney and S. M. dos SantosVolume 8 A history of control engineering, 1800-1930 S. BennettVolume 14 Optimal relay and saturating control system synthesis E. P. RyanVolume 15 Self-tuning and adaptive control: theory and application

C. J. Harris and S. A. Billings (Editors)Volume 16 Systems modelling and optimisation P. NashVolume 18 Applied control theory J. R. LeighVolume 19 Stepping motors: a guide to modern theory and practice P. P. AcamleyVolume 20 Design of modern control systems D. J. Bell, P. A. Cook and N. Munro (Editors)Volume 21 Computer control of industrial processes S. Bennett and D. A. Linkens (Editors)Volume 23 Robotic technology A. Pugh (Editor)Volume 26 Measurement and instrumentation for control M. G. Mylroi and G. Calvert

(Editors)Volume 27 Process dynamics estimation and control A. JohnsonVolume 28 Robots and automated manufacture J. Billingsley (Editor)Volume 30 Electromagnetic suspension—dynamics and control P. K. SlnhaVolume 31 Modelling and control of fermentation processes J. R. Leigh (Editor)Volume 32 Multivariable control for industrial applications J. O'Reilly (Editor)Volume 34 Singular perturbation methodology in control systems D. S. NaiduVolume 35 Implementation of self-tuning controllers K. Warwick (Editor)Volume 36 Robot control K. Warwick and A. Pugh (Editors)Volume 37 Industrial digital control systems (revised edition) K. Warwick and D. Rees

(Editors)Volume 38 Parallel processing in control P. J. Fleming (Editor)Volume 39 Continuous time controller design R. BalasubramanianVolume 40 Deterministic control of uncertain systems A. S. I. Zinober (Editor)Volume 41 Computer control of real-time processes S. Bennett and G. S. Virk (Editors)Volume 42 Digital signal processing: principles, devices and applications

N. B. Jones and J. D. McK. Watson (Editors)Volume 43 Trends in information technology D. A. Linkens and R. I. Nicolson (Editors)Volume 44 Knowledge-based systems for industrial control J. McGhee, M. J. Grimble and

A. Mowforth (Editors)Volume 45 Control theory—a guided tour J. R. LeighVolume 46 Neural networks for control and systems K. Warwick, G. W. Irwin and K. J. Hunt

(Editors)Volume 47 A history of control engineering, 1930-1956 S. BennettVolume 48 MATLAB toolboxes and applications for control A. J. Chipperfield and

P. J. Fleming (Editors)Volume 49 Polynomial methods in optimal control and filtering K. J. Hunt (Editor)Volume 50 Programming industrial control systems using IEC 1131-3 R. W. LewisVolume 51 Advanced robotics and intelligent machines J. O. Gray and D. G. Caldwel!

(Editors)Volume 52 Adaptive prediction and predictive control P. P. KanjilalVolume 53 Neural network applications in control G. W. Irwin, K. Warwick and K. J. Hunt

(Editors)Volume 54 Control engineering solutions: a practical approach P. Albedos, R. Strietzel

and N. Mort (Editors)Volume 55 Genetic algorithms in engineering systems A. M. S. Zaizaia and P. J. Fleming

(Editors)Volume 56 Symbolic methods in control system analysis and design N. Munro (Editor)Volume 57 Flight control systems R. W. Pratt (Editor)Volume 58 Power-plant control and instrumentation D. LindsleyVolume 59 Modelling control systems using IEC 61499 R. LewisVolume 61 Nonlinear predictive control: theory and practice B. Kouvaritakis and

M. Cannon (Editors)Volume 63 Stepping motors: a guide to theory and practice, 4th edition P. Acarnley


Active Soundand Vibration Controltheory and applications

Edited byOsman Tokhi andSandor Veres

The Institution of Electrical Engineers


Published by: The Institution of Electrical Engineers, London,United Kingdom

©2002: The Institution of Electrical Engineers.

This publication is copyright under the Berne Convention and the UniversalCopyright Convention. All rights reserved. Apart from any fair dealing for thepurposes of research or private study, or criticism or review, as permitted underthe Copyright, Designs and Patents Act, 1988, this publication may bereproduced, stored or transmitted, in any forms or by any means, only with theprior permission in writing of the publishers, or in the case of reprographicreproduction in accordance with the terms of licences issued by the CopyrightLicensing Agency. Inquiries concerning reproduction outside those terms shouldbe sent to the publishers at the undermentioned address:

The Institution of Electrical Engineers,Michael Faraday House,Six Hills Way, Stevenage,Herts. SG1 2AY, United Kingdomwww.iee.org

While the authors and the publishers believe that the information and guidancegiven in this work are correct, all parties must rely upon their own skill andjudgment when making use of them. Neither the authors nor the publishersassume any liability to anyone for any loss or damage caused by any error oromission in the work, whether such error or omission is the result of negligenceor any other cause. Any and all such liability is disclaimed.

The moral rights of the authors to be identified as authors of this work have beenasserted by them in accordance with the Copyright, Designs and Patents Act1988.

British Library Cataloguing in Publication Data

Active sound and vibration control.—(IEE control engineeringseries; no.62)1. Vibration 2. Acoustical engineeringI. Tokhi, M. O. II. Veres, Sandor M.,1956- III Institution of Electrical Engineers620.3' 7

ISBN 0 85296 038 7

Printed from authors' CRCPrinted in the UK by Bookcraft Ltd, Bath


Contents

Foreword xiii

Authors xix

I Review of fundamentals 1

1 An overview of ASVC: from laboratory curiosity to commer-cial products 31.1 Introduction 31.2 Active Noise Control 4

1.2.1 Early investigations 41.2.2 The energy objection 41.2.3 The JMC theory 51.2.4 One-dimensional sound propagation, algorithms 61.2.5 Interaction of primary and secondary sources 101.2.6 Waveform synthesis for (quasi)periodic noise 121.2.7 Small volumes - personal noise protection 131.2.8 Local cancellation 131.2.9 Three-dimensional sound fields in enclosures 141.2.10 Free-field active noise control 16

1.3 Active Control of Vibrations 171.3.1 Early applications 171.3.2 AVC for beams, plates and structures 171.3.3 Active mounts 191.3.4 Civil engineering structures 201.3.5 Active and adaptive optics 20


vi Contents

1.3.6 Noise reduction by active structural control 211.4 Active Flow Control 221.5 Conclusions 23

2 ANC in three-dimensional propagation 252.1 Introduction 252.2 Active noise control structure 272.3 Physical extent of cancellation 30

2.3.1 The field cancellation factor 302.3.2 Three-dimensional description of cancellation 33

2.4 Limitations in the controller design 402.4.1 Single-input single-output structure 402.4.2 Single-input multi-output structure 44

2.5 System stability 472.5.1 Gain margin 492.5.2 Phase margin 52

2.6 Conclusions 54

3 Adaptive methods in active control 573.1 Introduction 573.2 Feedforward control 59

3.2.1 Single-channel feedforward control 593.3 Feedback control 65

3.3.1 Fixed feedback controllers 653.4 Internal model control 66

3.4.1 Adaptive feedback control 693.5 Conclusions 70

II Recent algorithmic developments 73

4 Multichannel active noise control: stable adaptive algorithms 754.1 Introduction 754.2 Multichannel active noise control problems 764.3 Structure and Algorithms 78

4.3.1 Error system description in Case 1 784.3.2 Robust adaptive algorithm 804.3.3 Error system description in Case 2 82

4.4 Identification-based adaptive control in case 1 83


Contents vii

4.4.1 Identification of equivalent primary and secondary chan-nel matrices 83

4.4.2 Identification-based adaptive controller 844.5 Experimental results using the proposed adaptive algorithms 854.6 Conclusions 894.7 Appendix: proof of the theorem 90

5 Adaptive harmonic control: tuning in the frequency domain 975.1 Introduction 975.2 Problem formulation 1005.3 A frequency selective RLS solution 1035.4 A frequency selective LMS solution 1075.5 Simulation example 1105.6 Conclusions 115

6 Model-free iterative tuning 1176.1 Introduction to iterative controller tuning 1176.2 The online tuning scheme 1216.3 The online FSF tuning scheme 1246.4 Simulations 1266.5 Conclusions 132

7 Model-based control design for AVC 1357.1 Introduction 1357.2 Problem description 1377.3 HQO controller optimisation under model uncertainty 1437.4 Examples 145

7.4.1 Glass plate attenuation 1457.4.2 Active mounts 1487.4.3 Instrument base plate/enclosure attenuation 150

7.5 Identification of empirical models for control 1517.6 Conclusions 154

8 ANVC using neural networks 1598.1 Introduction 1598.2 Neural networks 161

8.2.1 Neural network models 1618.2.2 Multilayered perceptron networks 1618.2.3 Radial basis function networks 1638.2.4 Structure validation 166


viii Contents

8.3 Nemo-active noise control 1678.3.1 Frequency-response measurement scheme 1698.3.2 Decoupled linear/nonlinear system scheme 1708.3.3 Direct neuro-modelling and control scheme 173

8.4 Implementations and results 1758.4.1 Frequency-response measurement scheme 1768.4.2 Decoupled linear/nonlinear system scheme 1768.4.3 Direct neuro-modelling and control scheme 179

8.5 Conclusions 182

9 Genetic algorithms for ASVC systems 1859.1 Introduction 1869.2 The genetic algorithm 187

9.2.1 Coding selection for search variables 1919.2.2 Parent selection 1939.2.3 Crossover 1979.2.4 Mutation 2009.2.5 Sharing 201

9.3 Control source location optimisationexample 2039.3.1 Analytical model 2039.3.2 Genetic algorithm formulation 2069.3.3 Results 208

9.4 Example of control filter weightoptimisation 214

9.5 Conclusions 2209.6 Acknowledgments 220

III Applications 221

10 ANC Around a human's head 22310.1 Introduction 22310.2 Outline of the system 22410.3 Simulation 228

10.3.1 Purpose of simulation 22810.3.2 ANC for a single primary source propagation 22910.3.3 Diffuse sound field 230

10.4 Conclusions 237


Contents ix

11 Active Control of Microvibrations 24111.1 Introduction 24211.2 System description and modelling 244

11.2.1 Mass loaded panel 24411.2.2 Modelling of equipment loaded panels 251

11.3 Model verification 25611.4 Control systems design 26011.5 Robustness analysis 26711.6 Conclusions 271

12 Vibration control of manipulators 27512.1 Introduction 27512.2 The flexible manipulator system 278

12.2.1 Dynamic formulation 27812.2.2 The flexible manipulator test rig 281

12.3 Open-loop control 28212.3.1 Filtered torque input 28312.3.2 Gaussian-shaped torque input 287

12.4 Switching surface and variable structure control 29312.4.1 Switching surface design 29612.4.2 Stability analysis of the switching surface 29812.4.3 Adaptive variable structure control scheme 30012.4.4 Simulations 302

12.5 Adaptive joint-based collocated control 31012.6 Adaptive inverse-dynamic active control 31212.7 Conclusions 316

13 ANC in an electric locomotive 31913.1 Introduction 31913.2 Noise sources in electric trains 320

13.2.1 Aerodynamic noise 32013.2.2 Wheel-rail noise 32113.2.3 Equipment on the locomotive 32113.2.4 Electric motors 321

13.3 Locomotive noise characterisation 32213.3.1 Noise measurements inside the locomotive 32313.3.2 Noise characterisation 32313.3.3 Cabin noise analysis (microphones 1, 2, 3) 32413.3.4 Fan compressor noise (microphone 4) 32513.3.5 Air conditioner noise (microphone 5) 326


x Contents

13.3.6 Aerodynamic noise (microphone 6) 32613.3.7 Wheel-rail noise (microphone 7) 326

13.4 Generalities of active control approaches for cabin noise reduction32713.5 Noise control at source 32713.6 A target noise control strategy 33313.7 Main results of the field experimentation 33813.8 Conclusions 33913.9 Acknowledgements 34013.10Appendix 341

13.10.1 Introduction 34113.10.2 Digital processing circuit 34113.10.3 Analogue interface board 34313.10.4 Software environments 344

14 ANC for road noise attenuation 34514.1 Introdution 34514.2 Constraint multiple filtered-x LMS algorithm 34714.3 Constraint XLMS algorithm using an IIR-based filter 34814.4 Experimental results 34914.5 Conclusions 35314.6 Acknowledgments 353

15 Techniques for real-time processing 35515.1 Introduction 35515.2 The cantilever beam system 35915.3 Active vibration control 36015.4 Hardware architectures 363

15.4.1 Uniprocessor architectures 36315.4.2 Homogeneous architectures 36415.4.3 Heterogeneous architectures 364

15.5 Software support 36615.6 Partitioning and mapping of algorithms 36615.7 Implementations and results 368

15.7.1 Interprocessor communication 36815.7.2 Compiler efficiency 37415.7.3 Code optimisation 37415.7.4 Simulation algorithm 37715.7.5 The identification algorithm 37915.7.6 The control algorithm 379


Contents xi

15.7.7 The combined simulation, identification and control al-gorithm 380

15.7.8 Comparative performance of the architectures 38015.8 Conclusions 382

Bibliography 389

Index 421



Foreword

Active control of sound and vibration has emerged as an important area ofscientific and technological development in recent years. The general theoryof wave interference, which is used as the basis of active control of sound andvibration, reportedly emerged in the 17th century. Initial principles of ac-tive control, on the other hand, have been reported in the late 1870s and theearly 1930s. Since then, considerable effort has been devoted to the develop-ment and realisation of methodologies for the control of sound and vibrationin various application areas. These have included analyses and reformulationsof Huygen's principle of wave interference, parametric and nonparametric in-terpretations of the process of cancellation, performance assessment methodsand fixed and adaptive/intelligent techniques within signal processing and con-trol frameworks. These efforts have also identified and, to some extent, haveaddressed important issues of theoretical and practical significance, such asthe nature of the sound/vibration (disturbance), system complexity, stability,causality, and implementation-related factors.

The type and nature of the source of disturbance has provided the mainmotivation for exploring different control structures and design criteria. Thetype of source, whether considered as compact or distributed, provides anopportunity to investigate single-input and multi-input types of control struc-ture, accordingly. Similarly, the performance requirements at the system out-put level, whether cancellation is required at a specific point or over an ex-tended region within the propagating medium, has stimulated investigationsinto single-output and multi-output types of control structure. Permutationsof such options at the input and output levels thus provide considerable roomfor design flexibility. In either case, two distinct categories of control struc-ture, namely, feedback and feedforward, have emerged over the years. Amongthese, the feedback control structure corresponding to a standard classic feed-back control system has attracted considerable attention. However, the main


xiv Foreword

difficulty arising in the design and realisation of active control systems basedon such a control structure has been due to large controller gain requirementsand the resulting implications on the stability of the system. This controlstructure does offer a great deal of potential in that a vast number of standardcontrol system design methods and criteria can be utilised without too muchdifficulty. However, the design of active control systems based on this typeof control structure will inevitably require a compromise between system per-formance and system stability. Feedforward control structures, on the otherhand, offer a great deal of flexibility because they include feedback controlstructures as special cases. Moreover the problem of controller readabilitydue to large gains is resolved with this control structure. However, the issue ofnonminimum phase characteristics, commonly exhibited by sound/vibrationsystems, is of relevance and forms an important design consideration whenmaintaining controller and system stability.

The nature of the source of disturbance is an influential factor in the choiceof control strategy. A simple control mechanism may suffice to deal effectivelywith tonal disturbances. However, if the disturbance is of a broadband na-ture, the control mechanism has to produce a required set of characteristicsover a broad frequency range. Further levels of complexity become necessary,depending on whether the disturbance is stationary, time varying or randomin nature. Previous work has established that with time-varying or randomphenomena in the system, the control mechanism is required to incorporatean adaptive capability to track variations in system characteristics and mod-ify the control signal accordingly so that the desired performance is achievedand maintained. This has formed the motivation for much of the research intoadaptive methods such as adaptive filtering techniques, self-tuning control andmodel-reference adaptive control. These have mainly incorporated traditionalparameter estimation techniques such as least mean squares (LMS), recursiveleast squares (RLS) and their variants. Moreover, these methods have com-monly used linear parametric models. This is largely due to the simplicitywhich such models provide in the analysis and design process. However, newmethodologies, which make use of the optimisation capabilities of genetic algo-rithms (GAs) and the learning capabilities of neural networks, are finding theirway into the area of active control. In parallel with these, investigations anddevelopment of non-linear modelling and control techniques for active controlare currently in progress. The design of active control systems incorporatingsoft computing methods such as neural networks, GAs and fuzzy logic tech-niques provide a further level of development in the area of active control, andsome of the recent developments are reported in this book.

Intelligent control methods provide opportunities for developing new con-


Foreword xv

trol strategies. Neural networks, for example, have successfully been used in anumber of engineering applications, including modelling and control of linearand nonlinear dynamic systems. The potential of neural networks can be ex-ploited in devising suitable active control techniques. Similarly, GAs provideefficient nonlinear search methods resulting in accurate solutions. Accordingly,an opportunity is provided with GAs to explore, establish and optimise thegeometrical arrangement of components in an active control system for en-hanced performance as well as to identify the system model. The exploitationof the potentials of neural networks and GAs is evidenced in the literature,to some extent, in relation to the design of active control systems, and someof the recent developments are reported in this book. However, further de-velopments in the analysis and design of active control systems based on softcomputing methods are still emerging.

Stability has formed an important design issue in active control systems.This issue has been addressed in the case of airborne noise in ducts, for ex-ample, by developing multi sensor/multi source systems, so as to isolate thedetector sensor from the secondary source radiation. Moreover, analyses basedon relative stability measures have been provided for active noise control sys-tems in three-dimensional sound fields. Design methods such as H-infinity andinternal model control have been used to further address this issue, and someof these developments are reported in this book.

Owing to the advantages that digital implementation of controllers pro-vide over corresponding analogue implementations, active control algorithmsare commonly implemented using digital computing techniques. As the per-formance demands and hence the design complexity of the system increase, sodo the computing power requirements of the computation domain utilised forthe application. Such a trend has motivated the utilisation of special-purposedigital signal processing (DSP) devices, in either sequential or parallel forms,in active control applications. In either case, owing to a mismatch betweenthe computation requirements of the algorithm and the computing resourcesof the processors, efficient real-time performance may not be achieved. Thishas economic implications on the design and development of such systems.Thus, investigations into efficient computing methods involving a variety ofprocessor types to allow close matching of algorithms to processors, usingDSP and parallel processing methods, can lead to favourable developmentsin the realisation of active control systems. Some of the recent developmentsin high-performance computing for real-time implementation of active controlalgorithms are reported in this book.

Developments in active control have allowed successful application of theconcept in numerous industrial areas. Some of these include control of noise


xvi Foreword

in ventilation systems, aircraft, automobiles and refrigerators and vibrationcontrol in vehicle driver/passenger seats and helicopters. Several companiessell headsets for the cancellation of noise in a variety of environments. Otherapplications include the control of flexible structures such as flexible robotmanipulators and rotating machines, and in building engineering.

This book is an attempt to address some of the issues highlighted above.Accordingly, the purpose of this book is to report on established fundamentaland new knowledge in the area of active sound and vibration control. Thisincludes theoretical developments, algorithmic developments and practical ap-plications. The book is divided into 15 chapters. The opening Chapter 1provides a comprehensive review of previous developments in active controltechniques, from the initial principles to the current state. The process ofnoise cancellation in a three-dimensional propagation medium, design assess-ment of active noise control systems using to the zones of cancellation andreinforcement, and additionally geometrical design considerations to achieverobust and stable performance are presented in Chapter 2. Methodologies andissues surrounding adaptive and iterative control techniques are addressed inChapters 3—7. Among these, Chapter 3 reviews a number of adaptive con-trol techniques, followed by specific methodologies and treatments in Chap-ters 4—7. Chapter 4 proposes stability-assured adaptive algorithms to updateadaptive feedforward controllers. Chapter 5 discusses adaptive control basedon control at individual harmonics for cancellation of periodic disturbances.In Chapter 6 a model-free time-domain iterative controller tuning method isintroduced and extended for periodic noise cancellation using a two-degree-of-freedom controller. Chapter 7 summarises the main ideas of controller tuningvia iterative refinement of models and controller redesign. Some of the newand recent developments in the areas of neuro and genetic modelling and con-trol adopted for active control are presented in Chapters 8 and 9. In thesechapters, the optimisation capabilities of GAs and the learning capabilities ofneural networks are demostrated in terms of their exploitation and utilisationfor active control solutions. Chapters 10—14 are essentially addressing the ap-plications domain of active control, where specific methodologies are adoptedand applied to relevant applications. Chapter 15 discusses digital computingtechniques and demonstrates how these techniques can be utilised and adoptedfor practical realisation of active control methodologies.


Foreword xvii

The editors would like to thank Thomas Meurers, Galina Veres, Alfred Tanat Southampton University and Takatoshi Okuno at Sheffield University fortheir assistance in correcting the proofs and to Roland Harwood and DianaLevy at the IEE for their encouragement throughout the preparation of thisbook.

M O TokhiUniversity of SheffieldS M VeresUniversity of SouthamptonMarch 2002



Authors

S. J. ElliottInstitute of Sound and Vibration Research, University of Southampton,Southampton, UK, Email: [email protected]^

M. Font anaUniversity of Naples, Federico II, Italy, Email: [email protected]

D. GuickingDrittes Physikalisches Institut, University of Gottingen,Gottingen, Germany, Email: [email protected]

S. Honda and H. HamadaDepartment of Information and Communication Engineering,Tokio Denki University, Tokio, Japan, Email: [email protected]

M. A. HossainSchool of EngineeringSheffield Hallam University, Sheffield, UK

1 email addresses of corresponding authors are indicated


xx Authors

C. H. Hansen, M. T. Simpson and B. S. Cazzo-latoDepartment of Mechanical Engineering, University of Adelaide,Adelaide, South Australia, Email: [email protected]

Y. Park, H. S. Kim and S.H. OhDepartment of Mechanical EngineeringKorea Advanced Institute of Science and TechnologyScience Town, Taejon, Email: [email protected]

R. S. LangleyDepartment of Engineering, University of Cambridge, UK

B. MocerinoAnsaldo Transporti, Napoli, Italy

E. RogersDepartment of Electronics and Computer Science, University of Southampton,UK, Email: [email protected]

A. Sano, T. Shimizu, T. Kohno, H. OhmoriDepartment of System Design Engineering, Keio University,Keio, Japan, Email: [email protected]

J. StoustrupDepartment of Control Engineering, Aalborg University, Denmark

M. O. Tokhi, R. Wood, K. Mamour, Wen-JimCao, Jian-Xin Xu, H. PoerwantoDepartment of Automatic Control and Systems Engineering,University of Sheffield, UK, Email:[email protected]


Authors xxi

S- M. Veres, G. S. Aglietti, T. Meurers, S. B.GabrielSchool of Engineering Sciences, University of Southampton,Southampton, UK, Email: [email protected]

A. Vecchio, L. LecceUniversita di Napoli, Napoli, Italy

M. ViscardiActive S.r.L, Napoli, Italy, Email: [email protected]



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Active Sound and Vibration Control: theory and applications Volume 31 || Front Matter

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