EP0615648A1 - Active noise control of an enclosure with multiple transducers - Google Patents
Active noise control of an enclosure with multiple transducersInfo
- Publication number
- EP0615648A1 EP0615648A1 EP92905531A EP92905531A EP0615648A1 EP 0615648 A1 EP0615648 A1 EP 0615648A1 EP 92905531 A EP92905531 A EP 92905531A EP 92905531 A EP92905531 A EP 92905531A EP 0615648 A1 EP0615648 A1 EP 0615648A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- noise
- enclosure
- noise source
- speaker
- openings
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
- G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
- G10K11/1783—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase handling or detecting of non-standard events or conditions, e.g. changing operating modes under specific operating conditions
- G10K11/17833—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase handling or detecting of non-standard events or conditions, e.g. changing operating modes under specific operating conditions by using a self-diagnostic function or a malfunction prevention function, e.g. detecting abnormal output levels
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
- G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
- G10K11/1785—Methods, e.g. algorithms; Devices
- G10K11/17857—Geometric disposition, e.g. placement of microphones
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
- G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
- G10K11/1785—Methods, e.g. algorithms; Devices
- G10K11/17861—Methods, e.g. algorithms; Devices using additional means for damping sound, e.g. using sound absorbing panels
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
- G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
- G10K11/1787—General system configurations
- G10K11/17879—General system configurations using both a reference signal and an error signal
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
- G10K2210/10—Applications
- G10K2210/105—Appliances, e.g. washing machines or dishwashers
- G10K2210/1054—Refrigerators
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
- G10K2210/10—Applications
- G10K2210/106—Boxes, i.e. active box covering a noise source; Enclosures
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
- G10K2210/30—Means
- G10K2210/321—Physical
- G10K2210/3216—Cancellation means disposed in the vicinity of the source
Definitions
- the present invention relates to the development of an improved arrangement for controlling repetitive phenomena cancellation in an arrangement wherein a plurality of residual repetitive phenomena sensors and a plurality of cancelling actuators are provided.
- the repetitive phenomena being cancelled in certain cases may be unwanted noise, with microphone sensors and loudspeaker as the repetitive phenomena sensors and cancelling actuators, respectively.
- the repetitive phenomena being cancelled in certain other cases may be unwanted physical vibrations, with vibration sensors and counter vibration actuators as the repetitive phenomena sensors and cancelling actuators, respectively.
- the system consists of a set of Na actuators driven by a controller that produces a signal C which is a Na x 1 column vector of complex numbers.
- a set of Ns sensors measures the sum of the actuator signals and undesired noise.
- V is a Ns x 1 column vector of noise components and H is the Ns x Na transfer function matrix between the actuators and sensors at the harmonic of interest.
- the problem addressed by the present invention is to choose the actuator signals to minimize the sum of the squared magnitudes of the residual components.
- the residual with Copt would be
- the present invention provides methods and arrangements for accommodating the interaction between the respective actuators and sensors without requiring a specific pairing of the sensors and actuators as in prior art single point cancellation techniques such as exemplified by U.S. Patent 4,473,906 to Warnaka r U.S. Patents 4,677,676 and 4,677,677 to Eriksson r and U.S. Patents 4,153,815, 4,417,098 and 4,490,841 to Chaplin.
- the present invention is also a departure from prior art techniques such as described in the above-mentioned Elliott et al. article and U.S. Patent 4,562,589 to Warnaka which handle interactions between multiple sensors and actuators by using time domain filters which to not provide means to cancel selected harmonics of a repetitive phenomena.
- Active noise control has been shown to be effective in reducing low frequency noise in applications such as mufflers, headsets, engine mounts, fans, etc.
- Adaptive control has proved to be an effective technique for the implementation of active noise attenuation.
- Most applications have focused on single channel ada. _ve control (one sensor and actuator pair) or multiple channels when the interactions between channels is negligible.
- Applications such as cabin quieting and active enclosures have made apparent the need for multiple channel control algorithms. In these applications beca- e of the complexity of the noise source, a single transduce- will not be able to provide attenuation at the required regions. Additionally, interactions on the multiple transducers can cause adaptive algorithms to become unstable unless the interactions are accounted for in the control process.
- University of Maryland has developed the MISACT algorithm. This invention considers the problem of controlling noise radiating from a enclosure with multiple openings and multiple transducers. Performance of the MISACT Algorithm will be shown both experimentally and using a simulation model.
- a primary object of this invention is to provide an enclosure having multiple means to quiet sounds therein.
- Another object of this invention is the provision of multiple transducers within an enclosure to allow for multiple openings in the enclosure so as to facilitate fluid flow.
- Still another object of this invention is the application of a multiple interacting actuators and sensors algorithm to the task of quieting an enclosure.
- Yet another object of this invention is the use of a multi-channel active noise cancellation system in the quieting by a noise cancellation system of an enclosure.
- Fig 1 is a diagrammatic view of a multi-channel active noise cancellation system showing the overall system
- Fig 2 shows a noise spectrum plot of frequency versus sound level
- Fig 3 shows a similar noise spectrum plot of frequency versus sound level at the residual microphone location
- Fig 4 shows a specific application of the multiple channel approach to silencing a refrigerator compressor
- Fig 5 is a block diagram of the algorithm frequency time domain approach to controlling the instant system.
- the application of active noise quieting suggests itself to the area of home appliances.
- Home appliances do not produce noise levels that are dangerous or very obnoxious.
- the purpose of quieting appliances falls under the goal of providing a kitchen with an overall sound power level not greater than 40 dBA or to provide an appliance quieter than the competition.
- refrigerators, microwaves, rangehoods and dishwashers are all candidates for quieting techniques.
- Fans, motors and fluid noise are all present in the appliances mentioned above.
- Quieting techniques will have to address all the noise sources in a particular appliance. Quieting one source may well make a previously masked source annoying.
- a typical kitchen refrigerator has two main sources of noise, the compressor and the freezer compartment fan.
- the compressor consists of an electric motor and compressor device such as a piston.
- the fan is usually an axial type mounted in the freezer compartment.
- the enclosure referred to in this application can be either of these compartments.
- the compressor motor turns at a rate slightly slower than the line frequency, e.g. 58.5 Hz instead of 60 Hz. This frequency is the fundamental rate of the noise heard from the compressor. Harmonics of this fundamental at varying amplitudes are then heard.
- the refrigeration system has other noise sources also. There is a tone around 1500 Hz that varies in amplitude as a function of time that is produced in the piston part of the compressor and is fluid borne into the cooling coils where it can be heard.
- the expansion valve in the freezer compartment produces noisy turbulent fluid flow in the return line to the compressor. This noise varies with time and is proportional to the amount of Freon in the system that is being moved by the compressor (much less noticeable if the Freon level is low) .
- a simulation of the MISACT algorithm was developed to assist in predicting the performance of the attenuator system.
- the simulator uses a model of the operating environment to reproduce the interactions between actuators and sensors and can either be user defined or experimentally measured.
- the simulator will accept up to four actuators and four sensors, along with user inputs for the noise type and frequency range, transfer functions type (measured or user defined) and sample rates.
- the transfer functions between all speakers and microphones were measured in real time by the NCT 2010 controller.
- Simulation runs were made with noise frequencies of 228 and 456 Hz.
- Results are tabulated in Table 1 for both noise frequencies.
- the simulation results show that when full interaction between sensors is used, the overall noise level of both noise frequencies is reduced. However, when the interactions are not used the algorithm becomes unstable at around 228 Hz.
- FIG. 1 For experimental measurements an enclosure as in Figure 1 was constructed. The sides of the enclosure were constructed of plywood. A speaker inside the enclosure served as the noise source. Two 6 inch ports were used as outlets. Speakers were mounted to inject the cancelling signal at each port. Microphone elements were mounted at the top of the cabinet to provide the feedback signal. Both microphones and speakers were connected to a NCT 2010 MISACT controller. A synthetic noise source was connected to the speaker inside the enclosure and provided a speed signal to the controller. A B&K type 2230 sound level meter was used to measure the overall noise reduction along with a Tektronix 2630 spectrum analyzer. The controller performed a calibration to determine the system response between the full matrix of speakers and microphones. A noise signal consisting of 228 and 456 Hz was then generated in the enclosure.
- the controller was then enabled and allowed to reach steady state operating condition.
- the noise spectrum measured at the monitor microphone is shown in Figure 2 for the controller both on and off.
- the overall noise level was reduced from 59.3 dBA to 45.5 dBA.
- the control was implemented with two independent channels.
- the response at the two error microphones is shown in Figure 3. While the 456 Hz tone is reduced, the level of the 228 Hz tone is increased. It should be noted that the signal level was prevented from increasing further by limiting logic in the software.
- Table 1 shows the simulation results for interacting versus independent control.
- a shell was constructed around the compressor compartment to take out the high frequency tones and random noise. This shell also had an input slit and output port to allow heat from the compressor to escape. The shell and port were designed to resonate at approximately 60 Hz. Testing showed that the compressor shell temperature stayed under manufacturer's guidelines even when subjected to an ambient temperature of 110 degrees F.
- the antinoise actuator was a speaker inside the shell.
- the speaker cabinet was optimized for the low frequency fundamental, 58.7 Hz, of the compressor.
- a microphone on the outside of the shell served as the residual sensor.
- the NCT control algorithm then calculated the impulse response from the speaker to the residual microphone and produced the correct cancelling signal.
- a reduction of 10 dBA rear and 5 dBA front over an identical unmodified refrigerator was obtained.
- the uniqueness of the solution is as follows:
- This invention shows control of low frequency noise from an enclosure with multiple transducers. It was shown that simulation can provide insight about performance of an active control system.
- the simulation model has been used as an analytical tool on electronic mufflers and vibration mounts. Furthermore it was demonstrated both through simulation and experiment that the MISACT algorithm will remain stable in situations where independent control channel may become unstable.
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Multimedia (AREA)
- Soundproofing, Sound Blocking, And Sound Damping (AREA)
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
- Transducers For Ultrasonic Waves (AREA)
- Amplifiers (AREA)
- Exhaust Silencers (AREA)
- Noise Elimination (AREA)
Abstract
Description
Claims
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/US1991/008772 WO1993011529A1 (en) | 1991-12-02 | 1991-12-02 | Active noise control of an enclosure with multiple transducers |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0615648A1 true EP0615648A1 (en) | 1994-09-21 |
EP0615648A4 EP0615648A4 (en) | 1995-04-19 |
EP0615648B1 EP0615648B1 (en) | 1999-04-21 |
Family
ID=22225986
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP92905531A Expired - Lifetime EP0615648B1 (en) | 1991-12-02 | 1991-12-02 | Active noise control of an enclosure with multiple transducers |
Country Status (7)
Country | Link |
---|---|
EP (1) | EP0615648B1 (en) |
JP (1) | JPH07504991A (en) |
AT (1) | ATE179273T1 (en) |
CA (1) | CA2124183C (en) |
DE (1) | DE69131170T2 (en) |
DK (1) | DK0615648T3 (en) |
WO (1) | WO1993011529A1 (en) |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0645004A4 (en) * | 1992-06-10 | 1996-05-08 | Noise Cancellation Tech | Active acoustical controlled enclosure. |
US8054984B2 (en) | 2006-10-16 | 2011-11-08 | Bsh Home Appliances Corporation | Sound altering apparatus |
CA2606442A1 (en) * | 2006-10-16 | 2008-04-16 | Bsh Home Appliances Corporation | Sound altering apparatus |
DE102008038751B3 (en) * | 2008-08-12 | 2010-04-15 | Fresenius Medical Care Deutschland Gmbh | Reverse osmosis system with a device for noise reduction and method for noise reduction of a reverse osmosis system |
DE102009024343A1 (en) | 2009-06-09 | 2010-12-16 | Rohde & Schwarz Gmbh & Co. Kg | Electronic device with noise suppression system |
CN105139861B (en) * | 2015-08-24 | 2018-08-17 | 昆明科林科技工程有限公司 | A kind of reduction method and device administered for man-made noise |
WO2018111233A1 (en) | 2016-12-13 | 2018-06-21 | Halliburton Energy Services, Inc. | Reducing far-field noise produced by well operations |
WO2018125116A1 (en) | 2016-12-29 | 2018-07-05 | Halliburton Energy Services, Inc. | Active noise control for hydraulic fracturing equipment |
EP4327322A1 (en) * | 2021-04-21 | 2024-02-28 | Sariaslan, Esra | Method for reducing noise in machines |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2204916A (en) * | 1987-05-19 | 1988-11-23 | British Gas Plc | Gaseous flow silencer |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4665549A (en) * | 1985-12-18 | 1987-05-12 | Nelson Industries Inc. | Hybrid active silencer |
DE68911112T2 (en) * | 1988-02-19 | 1994-05-26 | Noise Cancellation Tech | EXHAUST SILENCER SYSTEM FOR INTERNAL COMBUSTION ENGINE. |
JPH083395B2 (en) * | 1988-09-30 | 1996-01-17 | 株式会社東芝 | Silencer for cooling system |
-
1991
- 1991-12-02 DK DK92905531T patent/DK0615648T3/en active
- 1991-12-02 JP JP4505211A patent/JPH07504991A/en active Pending
- 1991-12-02 AT AT92905531T patent/ATE179273T1/en not_active IP Right Cessation
- 1991-12-02 EP EP92905531A patent/EP0615648B1/en not_active Expired - Lifetime
- 1991-12-02 CA CA002124183A patent/CA2124183C/en not_active Expired - Fee Related
- 1991-12-02 DE DE69131170T patent/DE69131170T2/en not_active Expired - Fee Related
- 1991-12-02 WO PCT/US1991/008772 patent/WO1993011529A1/en active IP Right Grant
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2204916A (en) * | 1987-05-19 | 1988-11-23 | British Gas Plc | Gaseous flow silencer |
Non-Patent Citations (2)
Title |
---|
CONFERENCE PROCEEDINGS: RECENT ADVANCES IN ACTIVE CONTROL OF SOUND AND VIBRATION, 1991, USA page 246-257 KH. EGHTESADI ET AL. 'Development of the simulation model of the multiple interacting sensors and actuators (MISACT) for an active control system' * |
See also references of WO9311529A1 * |
Also Published As
Publication number | Publication date |
---|---|
WO1993011529A1 (en) | 1993-06-10 |
ATE179273T1 (en) | 1999-05-15 |
EP0615648B1 (en) | 1999-04-21 |
DE69131170T2 (en) | 1999-11-18 |
DK0615648T3 (en) | 1999-11-01 |
CA2124183C (en) | 1996-08-27 |
EP0615648A4 (en) | 1995-04-19 |
JPH07504991A (en) | 1995-06-01 |
DE69131170D1 (en) | 1999-05-27 |
CA2124183A1 (en) | 1993-06-10 |
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