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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)
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)
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Ate
nuac
ión
(dB
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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
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SP
L(dB
)
0 100 200 300 400 500 600 700-140
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f(H )
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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 ?
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SP
L (d
BA
)
Is the system robust to disturbances in the plant and the excitation ?
2000 2500 3000 3500 4000 4500
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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
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A2A4
A6A8
A9 A10
A1
A5
A3 A7
Contrôle Actif Acoustique
Optimisation of the physical part by means of natural algorithms
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