MASTER "MECANIQUE, PHYSIQUE ET INGENIERIE" ,Spécialité Recherche "Acoustique" (M2)
Deuxième phase: Modules spécialisésS5 : Contrôle actif et milieux poreux (Cédric MAURY)S5 : Contrôle actif et milieux poreux (Cédric MAURY)
Teresa Bravo MaríaTeresa Bravo Marí[email protected]
Contrôle Actif Acoustique
Schedule
I. Wednesday 8:30 – 12:30Theory of Active Noise Control (ANC)Exercises
II Thursday 8:30 – 10:30II. Thursday 8:30 10:30Theory of ANC
Thursday 10:30 12:30Thursday 10:30 – 12:30Real-life applications of ANC
III. Thursday 13:30 – 15:30Firts practical exercise ANCp
Thursday 15:30 – 17:30Second practical exercise ANC
Contrôle Actif Acoustique
Seco d p act ca e e c se NC
Real-life applications of Active Noise Control
Direct ApplicationsA i N i C l i f fi ldActive Noise Control in free fieldActive Headset (ear defender)Active Noise control in ducted systemsActive Noise control in ducted systemsActive Noise Control inside planes, vans and cars
Further applications of active control techniquesE i t l th i f d fi ld iExperimental synthesis of random pressure fields in laboratory conditionsThe reproduction of a random pressure field in aThe reproduction of a random pressure field in a transmission suite for the determination of the TL of a partition
Contrôle Actif Acoustique
Active Control of Transformer Noise, Conover 1956
Contrôle Actif Acoustique
Active Headset, (Carme 1988)
Contrôle Actif Acoustique
Active Headset (deAlba and Cobo, 1999)
15
20
5
10
Ate
nuac
ión
(dB
)
-5
050 63 80 10
0
125
160
200
250
315
400
500
630
800
1000
Frecuencia (Hz)
Contrôle Actif Acoustique
The design of near field acoustic arrays for audio applications
Institute of Sound and Vibration ResearchUniversity of Southampton, UK
Minimisation of interference between two people listening to different audio signals using loudspeakers in the headrests of adjacent seats.audio signals using loudspeakers in the headrests of adjacent seats.
Listening to channel 2 Listening to channel 1Listening to channel 2 Listening to channel 1
Dark zone Bright zone
Acoustic array
Contrôle Actif Acoustique
Active control in ducted systems
Sin CAR
Con CAR
Contrôle Actif Acoustique
Active control in ducted systems
-40
-20
0
100
-80
-60
SP
L(dB
)
0 100 200 300 400 500 600 700-140
-120
-100
f(H )
Contrôle Actif Acoustique
f(Hz)
Active Control of the noise transmitted through a windowwindow
(Kaiser et al, 2001)
Contrôle Actif Acoustique
Implementation of a multi-channel Active Noise Control System
Identify the dominant noise sources and the propagation paths.
Id tif th t f i t ti l t d i t b ti
y
Identify the type of noise: stationary, correlated, main perturbation frequency range
.
Determine the coherence between the noise and the reference signals.Place the sensors so the coherence would be the closest to unity.
Determine the sound pressure levels. Choose the actuator type. Place the optimal positions for control sources and error sensors.
Use the electronic control system to select a feedback or a feedforward control system, the sampling frequencies, the filters to apply…y , p g q , pp y
Select different types of algorithms, different coupled control systems, different control parameters etc
Contrôle Actif Acoustique
different control parameters, etc.
Active Sound Control in a propeller aircraft
System is standard fit onSystem is standard fit on the Dash 8 Q400(Stothers et al., 2002) P i di it ti f( , ) Periodic excitation of
fuselage by propeller(www.bombardier.com)
Contrôle Actif Acoustique
(www.bombardier.com)
Active Sound Control in a propeller aircraft(Stothers et al., 2002)( , )
Contrôle Actif Acoustique
Typical performance of an Active Sound System(Stothers et al 2002)(Stothers et al., 2002)
Contrôle Actif Acoustique
Active system with structural actuators
Contrôle Actif Acoustique
Active Control of Sound inside a van
Design and physical implementation of an active noise control system for control of the engine booming in a cabin vanfor control of the engine booming in a cabin van
Contrôle Actif Acoustique
Active Control of Sound inside a van
Contrôle Actif Acoustique
Experimental results at the error sensor positions100
80
90
(dB
)
50
60
70
SP
L (
2000 2500 3000 3500 400040
50
R.P.M
What is the effect of the control 76
78
80
82
)What is the effect of the control system out of the error sensor positions ?
70
72
74
76
SP
L (d
BA
)
Is the system robust to disturbances in the plant and the excitation ?
2000 2500 3000 3500 4000 4500
66
68
70
Contrôle Actif Acoustique
RPM
Local active control system inside a car (Elliott et al, 1986 )
Contrôle Actif Acoustique
Robust optimisation of the active system12 19 26 33 40 47 54
4
5
10
11
12
17
18
19
24
25
26
31
32
33
38
39
40
45
46
47
52
53
54
2
3
8
9
15
16
22
23
29
30
36
37
43
44
50
51
1
6
7
13
14
20
21
27
28
34
35
41
42
48
49
A2A4
A6A8
A9 A10
A1
A5
A3 A7
Contrôle Actif Acoustique
Optimisation of the physical part by means of natural algorithms
Classical optimisation methods: steepest descent algorithmsteepest descent algorithm
For the cost function in our problem (attenuation values) weproblem (attenuation values) we obtain a non-linear problem that cannot be solved by classical algorithms
Contrôle Actif Acoustique
Exhaustive search
dB 1 2 3 4 5 6 7 829 0 0 0 0 0 0 0 028 0 0 0 0 0 0 0 027 0 0 0 0 0 0 0 026 0 0 0 0 0 0 0 325 0 0 0 0 0 0 4 6324 0 0 0 0 0 1 29 20323 0 0 0 0 0 13 114 39222 0 0 0 0 2 26 221 74721 0 0 0 0 11 117 444 93320 0 0 0 1 29 200 517 76319 0 0 0 7 64 189 445 73518 0 0 1 18 55 131 372 83517 0 0 1 0 17 153 554 99317 0 0 1 0 17 153 554 99316 0 0 0 2 49 344 939 128615 0 0 0 17 130 408 772 96314 0 0 3 22 100 378 875 112313 0 0 1 19 146 480 880 88112 0 0 0 14 109 465 950 82811 0 0 1 34 219 662 982 74010 0 0 3 56 292 802 1050 6619 0 1 15 87 431 986 975 3828 0 0 10 163 671 1016 629 1888 0 0 10 163 671 1016 629 1887 0 1 40 291 685 695 344 916 0 9 90 304 496 432 204 535 0 13 101 266 348 271 100 74 2 20 62 163 222 137 35 0
Contrôle Actif Acoustique
3 1 18 86 174 181 87 5 02 2 11 68 140 105 15 0 01 3 38 77 42 6 0 0 00 8 9 1 0 0 0 0 0
Selection of the optimal configuration
Selection of the optimal positions by using the simulated annealing algorithm
Contrôle Actif Acoustique
Experimental resultsRobust optimisation for global control at the head heights
Active Control
Original field
Robust optimisation
Contrôle Actif Acoustique
Feedback Control System for Narrowband Control of Boom in a Car(Honda, 2001)
Contrôle Actif Acoustique
Other applications of active control techniques
The experimental synthesis of random pressure fields in laboratory conditions with an array of near-field loudspeakers:
Diffuse fieldDiffuse field
Plane Wave field
Turbulent Boundary Layer pressure fieldpressure field
Contrôle Actif Acoustique
Synthesis of a Turbulent Boundary Layer
Contrôle Actif Acoustique
Synthesis of a diffuse pressure field
(ωΠ
)
Sound Transmission Testing at Low Frequencies
(dB)(ωΠ
(ωΠlog10R(ωtrans
inc10
)))
Diffuse field (theory)
0.8
1
Diffuse field (theory)Diffuse field (model)
)cossinsincossin( zyxjktjeP
0.4
0.6
n fu
nctio
n
)( yjjinceP
0
0.2
Spa
tial c
orre
latio
0 0 5 1 1 5 2 2 5 3 3 5 4
-0.4
-0.2
Contrôle Actif Acoustique
0 0.5 1 1.5 2 2.5 3 3.5 4Distance divided by acoustic wavelenght (d/)
Experimental set-up
R i i
Z2
Z1
Receiving roomSource room
Y1
Y2
XOX1
X2O2
O1
s
rec
p10recsource A
slog10LLR
Contrôle Actif Acoustique
Sound reduction index with the sound intensity method
Source room Receiving room
p2source
Sound Intensity Microphone Probe
Contrôle Actif Acoustique
The reproduction of a diffuse field with an array of loudspeakersof loudspeakers
dD
ex
yW G yW G
x)WGD(yde
DGDG]GG[W †1 HHopt
Contrôle Actif Acoustique
Experimental verification
45
50
B)
30
35
40
on In
dex
(dB
15
20
25
und
Red
uctio
14 22.4 35.5 56 90 140 224 355 561 9005
10
15
F (H )
Sou
Contrôle Actif Acoustique
Frequency (Hz)
Th kThank youy
Contrôle Actif Acoustique
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