active noise control : study of the · pdf fileoutpass microphone signal micsig active output...

Event title (to be altered on title master)Presenter name – presenter job title (to be altered on title master)

Convergence speed, Latency time and Implementation on a boardActive Noise Control : Study of the algorithm

Paris – December, 15th 2009Marco Gallo – LMS International - [email protected]

Marco Gallo – Personal Presentation

� Born in Asti 26/06/1984

� B.Sc & M.Sc. in Automotive Engineering at Politecnico di Torino, 2008

� Several projects during M.Sc:

� Team member of Squadra Corse (2006-2008), Formula SAE team of Politecnico di Torino, as responsible of design and production of a dry sump system

� Internship @ University of Surrey, Guildford, Uk

� Marie Curie fellowship from July 2009 in the frame SMART STRUCTURES for LMS International (12 months)

� Main Research Topic: Active Car Noise Control

� Relational Skills: I enjoy team-working. I was 3 years responsible of the youth activities in San Damiano d’Asti, Asti, Italy. I played in many football team; my hobbies are football, reading, gardening, oenology.

2 - copyright LMS International - 2009

Agenda

2 Control Strategy - FxLMS

1 Introduction

3 FxLMS - Results

4

5

6

1 Introduction

Board - Processor

Control Strategy – NEX LMS

NEX LMS - Results


0 1 0 0 2 0 0 3 0 0 4 0 0 5 0 0 6 0 0 7 0 0 8 0 0 9 0 0 1 0 0 0- 1

- 0 . 5

0

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4

T i m e

Noi

se P

ress

ure

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U n w a n t e d N o is eA n t i - N o i s e S o u n dS u m m a t io n

• Sound reduction with destructive interference (Young’s principle)

• Obtained by the superposition of the original (primary) sound field with an artificially generated (secondary) sound field

Introduction – Young’s Principle


Introduction – Lueg Patent, 1936

Problem of cancelling sound in a duct

Problem of cancelling sound in an area

Noise attenuation in an open space


Agenda


1 Introduction

3 FxLMS - Results

4

5

6


Board - Processor


NEX LMS - Results


Control Strategy - Algorithm

Adaptive Feed Forward Strategy ( Fx-LMS)

• Aim : Achieve a pre-defined order level vs RPM profile, achieve a desired sound quality

• Controller should work with varying engine speeds, disturbance• Controller should have a fast convergence speed• The adaptive algorithm adjust the coefficients of the digital filter

w(n) = [w0(n) w1(n)….. wL-1(n)]T

• Steepest descent method, to minimize a quadratic cost function


W S-Function

FIR

Secondary PathModel

Sid

1

Secondary Path

y2'

1

Scope

S-Function

FXLMSReference

Signal

RefSig

Passive Output

OutPass

Microphone Signal

MicSig

Active Output

OutActDigital FilterSecondary Path

Adaptive Algorithm

Engine Sound

W S-Function

FIR

Secondary PathModel

Sid

1

Secondary Path

y2'

1

Scope

S-Function

FXLMSReference

Signal

RefSig

Passive Output

OutPass

Microphone Signal

MicSig

Active Output

OutAct

Adaptive Algorithm

Digital FilterSecondary Path

Control Strategy - Algorithm

)()()()1( nenxnwnw ⋅⋅+=+ µ

xx LPLP

1.001.0 << µ

• LMS algorithm for updating the coefficients of W:

• x(n): Reference Signal RPM

• e(n): Error Signal

• µ: Convergence Coefficient


Engine Sound

Agenda


1 Introduction

3 FxLMS - Results

4

5

6

3 FxLMS - Results

Board - Processor


NEX LMS - Results


FxLMS - Results

• Input: constant amplitude sinusoid

• Secondary path model : two poles

• Fast convergence near the secondarypath resonances

0 1 2 3 4 5 6 7 8 9 10-1

-0.8

-0.6

-0.4

-0.2

0

0.2

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1

Time [s]

Am

plitu

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66 Hz

83 Hz40 Hz

0 1 2 3 4 5 6 7 8 9 10-1

-0.8

-0.6

-0.4

-0.2

0

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1

Time [s]

Am

plitu

de

100 Hz

116 Hz133 Hz

0 1 2 3 4 5 6 7 8 9 10-1

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-0.6

-0.4

-0.2

0

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1

Time [s]

Am

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de

150 Hz

166 Hz200 Hz

FxLMS - Results


40

60

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160

180

200

0

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-1

-0.8

-0.6

-0.4

-0.2

0

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0.6

0.8

1

Time [s]

Freq [Hz]

Am

plitu

de

Agenda


1 Introduction

3 FxLMS - Results

4

5

6

4 Control Strategy – NEX LMS

Board - Processor


NEX LMS - Results



Reference Signal(Engine rpm)

Look up tableNormalization Filter

Engine sound

Equalization


Agenda


1 Introduction

3 FxLMS - Results

4

5

6

5 NEX LMS - Results

Board - Processor


NEX LMS - Results


NEX LMS - Results

0 1 2 3 4 5 6 7 8 9 10-2.5

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

Time [s]

Am

plitu

de

80 Hz

166 Hz

133 Hz

0 1 2 3 4 5 6 7 8 9 10-1.5

-1

-0.5

0

0.5

1

Time [s]

Am

plitu

de

200 Hz

233 Hz

266 Hz

0 1 2 3 4 5 6 7 8 9 10-1

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Time [s]

Am

plitu

de

266 Hz

333 Hz

400 Hz

Fast convergence for each frequencies!!


NEX LMS - Results

50

100

150

200

250

300

350

400

0

1

2

3

4

5

6

7

8

9

10

-3

-2

-1

0

1

2

3

Time [s]Freq [Hz]

Am

plitu

de


NEX LMS - Results

• For β=0 the residual noise is the unchanged primary disturbance

• For β=1: maximum reduction

• For β=+0.5: half reduction

• For β<0 the system amplifies the original disturbance.

)()()()()( * nyndnyndne β−=−=

0 1 2 3 4 5 6 7 8 9 10-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

Time [s]

Am

plitu

de

Beta = -1Beta = -0.5

Beta = 0

Beta = +0.5Beta = +1

)()1()( ndne β−≈

)()(

)()()(

wewd

wewdw

r

d

−−=β

)(

)(1)(

wd

wew d−≈β


Agenda


1 Introduction

3 FxLMS - Results

4

5

6

6 Board - Processor

Board - Processor


NEX LMS - Results


Latency time study


Latency time study

European Passenger CarDriver Front Passenger

Average Latency [ms] 16.50 16.70

Max Value [ms] 21.52 21.98

Min Value [ms] 9.89 10.64

Monovolume Car

Driver

Average Latency [ms] 12.64

Max Value [ms] 18.71

Min Value [ms] 9.17

American Passenger CarDriver Rear Passenger

Average Latency [ms] 11.87 11.79

Max Value [ms] 18.10 16.41

Min Value [ms] 7.05 8.73


Board for audio processing

PNX1005 Series- power and cost optimized- tm3282 350-400Mhz VLIW core- integrated USB2.0 OTG- 2x quad-multiplexed video input- HD 1080p/60 video in and out

Applications- 8 channel CIF H264 DVR

- 2xD1 H264 or 720p H264 encode

- H264 SD IP Camera with analytics

- Picture optimization


aNext Step

• Implementation of the algorithm (WIP)

• Test in the LMS research car

• MIMO implementation

• Implement adaptive feedforward control system in VCS

• Secondment @ VTT, Finland

• Based on :L. De Oliveira, 2009, “Active sound quality control: design tools and automotive applications”, Ph.D. thesis, K.U. Leuven, Fac. Eng., Dept. Mechanical Eng.


Event title (to be altered on title master)Presenter name – presenter job title (to be altered on title master)

Thank you

Paris – December, 15th 2009Marco Gallo – LMS International - [email protected]

active noise control : study of the · pdf fileoutpass microphone signal micsig active output...

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