WO2003073415A1 - Dispositif efficace de calcul permettant d'effectuer un controle optimal au moyen de limitations de controle - Google Patents

Dispositif efficace de calcul permettant d'effectuer un controle optimal au moyen de limitations de controle Download PDF

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Publication number
WO2003073415A1
WO2003073415A1 PCT/US2002/005845 US0205845W WO03073415A1 WO 2003073415 A1 WO2003073415 A1 WO 2003073415A1 US 0205845 W US0205845 W US 0205845W WO 03073415 A1 WO03073415 A1 WO 03073415A1
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WO
WIPO (PCT)
Prior art keywords
control
weighting
control weighting
command
command signal
Prior art date
Application number
PCT/US2002/005845
Other languages
English (en)
Inventor
Thomas A. Millott
Douglas G. Macmartin
Robert K. Goodman
James W. Fuller
Original Assignee
Sikorsky Aircraft Corporation
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Sikorsky Aircraft Corporation filed Critical Sikorsky Aircraft Corporation
Priority to AU2002244172A priority Critical patent/AU2002244172A1/en
Publication of WO2003073415A1 publication Critical patent/WO2003073415A1/fr

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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
    • G10K11/1785—Methods, e.g. algorithms; Devices
    • G10K11/17853—Methods, e.g. algorithms; Devices of the filter
    • G10K11/17854—Methods, e.g. algorithms; Devices of the filter the filter being an adaptive filter
    • 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
    • G10K11/17855—Methods, e.g. algorithms; Devices for improving speed or power requirements
    • 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
    • G10K11/17881—General system configurations using both a reference signal and an error signal the reference signal being an acoustic signal, e.g. recorded with a microphone
    • 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
    • G10K11/17883—General system configurations using both a reference signal and an error signal the reference signal being derived from a machine operating condition, e.g. engine RPM or vehicle speed
    • 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
    • G10K2210/128—Vehicles
    • G10K2210/1281—Aircraft, e.g. spacecraft, airplane or helicopter
    • 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
    • G10K2210/301—Computational
    • G10K2210/3016—Control strategies, e.g. energy minimization or intensity measurements
    • 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
    • G10K2210/301—Computational
    • G10K2210/3039—Nonlinear, e.g. clipping, numerical truncation, thresholding or variable input and output gain

Definitions

  • This invention relates to optimal control of a system. More particularly, this invention relates to active vibration and active sound control systems for the interior of helicopters.
  • Conventional active control systems consist of a number of sensors that measure the ambient variables of interest (e.g. sound or vibration), a number of actuators capable of generating an effect on these variables (e.g. by producing sound or vibration), and a computer which processes the information received from the sensors and sends commands to the actuators so as to reduce the amplitude of the sensor signals.
  • the control algorithm is the scheme by which the decisions are made as to what commands to the actuators are appropriate.
  • a problem may arise in such a control scheme when the control decision yields a command that exceeds the physical capabilities of the system, for example, if the command to an actuator exceeds the actuator's physical limits.
  • the present invention utilizes a varying control weighting to provide improved performance while avoiding saturation of the actuators.
  • a control weighting For a least-squares or quadratic performance index, one typically includes a weighting on the control amplitudes to avoid actuator saturation.
  • a constant weighting that is sufficient to ensure that no actuator ever saturates results in less than optimal performance.
  • This invention therefore modifies the control weighting to ensure that the maximum possible performance is always obtained subject to the saturation constraints.
  • the ambient vibration is measured by a plurality of sensors.
  • a plurality of command signals are generated over time based upon the measured vibration and based upon a control weighting. By varying the control weighting over time, the maximum possible performance is always obtained subject to the saturation constraints.
  • the control weighting may be varied based upon the magnitude of the command signals.
  • FIG. 1 shows a block diagram of the noise control system of the present invention.
  • FIG. 2 shows a vehicle in which the present invention may be used.
  • Control systems consist of a number of sensors which measure ambient vibration (or sound), actuators capable of generating vibration at the sensor locations, and a computer which processes information received from the sensors and sends
  • the control algorithm is the scheme by which the decisions are made as to what the appropriate commands to the actuators are.
  • FIG. 1 shows a block diagram 10 of an active control system.
  • the system
  • a disturbance source 103 produces undesired response of the structure 102.
  • the undesired disturbances are typically due to vibratory aerodynamic loading of rotor blades, gear clash, or other source of vibrational noise.
  • sensors 128(a)...(n) measure the ambient variables of interest (e.g. sound or vibration).
  • the sensors generally 128, are typically microphones or accelerometers, or virtually any suitable sensors.
  • Sensors 128 generate an electrical signal that corresponds to sensed sound or vibration.
  • the electrical signals are transmitted to filter 112 via an associated interconnector 144(a)...(n) (generally 144).
  • Interconnector 144 is typically wires or wireless transmission means, as known to those skilled in the art.
  • Filter 112 receives the sensed vibration signals from sensors 128 and performs filtering on the signals, eliminating information that is not relevant to vibration or sound control. The output from the filter 112 is transmitted to control unit 106 via interconnector 142 respectively. The control circuit 106 generates control signals that
  • a plurality of force generators 104(a)...(n) are used to generate a force capable of affecting the sensed variables (e.g. by producing sound or vibration).
  • Force generators 104(a)...(n) are typically speakers, shakers, or virtually any suitable actuators.
  • Force actuators 104 receive commands from 10 the control unit 106 via interconnector 134 and output a force, as shown by lines 132(a)...(n) to compensate for the sensed vibration or sound produced by vibration or sound source 103.
  • the control unit 106 is typically a processing module, such as a microprocessor, with processing capabilities.
  • Control unit 106 stores control algorithms control memory 15 105, or other suitable memory location.
  • Memory module 105 is, for example, RAM, ROM, DVD, CD, a hard drive, or other electronic, optical, magnetic, or any other computer readable medium onto which is stored the control algorithms described herein.
  • the control algorithms are the scheme by which the decisions are made as to what commands to the actuators 104 are appropriate. 20 For a least-squares or quadratic performance index, one typically includes a weighting on the control amplitudes to avoid actuator saturation. However, a constant weighting that is sufficient to ensure that no actuator ever saturates results in less than optimal performance. This invention therefore modifies the control weighting to ensure that the maximum possible performance is always obtained subject to the saturation
  • the computation can be performed at an update rate lower than the sensor sampling rate as described in the copending application entitled “Computationally Efficient Means for Active Control of Tonal Sound or Vibration,” which is commonly assigned.
  • This approach involves demodulating the sensor signals
  • control computations are therefore performed on the sine and cosine components at the frequency of interest for each sensor signal. These can be represented as a complex variable where the real part is equal to the cosine term, and the imaginary part is equal to the sine term.
  • the same control algorithm can therefore be 5 used for either low frequency disturbances or tonal disturbances, provided that complex notation is used. The approach will be described for such a demodulated tonal problem, but is equally applicable to low frequency disturbances.
  • the number of sensors is given by n s and the number of actuators n a .
  • the complex harmonic estimator variables that are calculated from the measurements of o noise or vibration level can be assembled into a vector of length n s denoted Z k at each sample time k.
  • the control commands generated by the control algorithm can likewise be assembled into a vector of length n a denoted U k .
  • the commands sent to the actuators are generated by multiplying the real and imaginary parts of this vector by the cosine and sine of the desired frequency. 5
  • the transfer function between actuators and sensors is roughly constant, and thus, the system can be modeled as a single quasi-steady complex transfer function matrix, denoted T.
  • T y is the response at the reference frequency of sensor i due to a unit command at the reference frequency on5 actuator j.
  • Many algorithms may be used for making control decisions based on this model.
  • W z , W u and Wg u are weighting matrices that are typically diagonsal on the0 sensors, control inputs, and rate of change of control inputs respectively.
  • a larger control weighting on an actuator ill result in a control solution with smaller amplitude for that actuator.
  • the matrix Y determines the rate of convergence of different directions in the control space, but does not affect the steady state solution.
  • control weighting values are fixed to a predefined value (based on experience), and are sometimes scheduled versus operating condition.
  • the value of control weighting which results in optimal performance on one day may not yield the same performance on a different day, or evens later during the same flight (e.g., due to weight, temperature, or humidity changes). Based on the above discussion, it would be desirable to be able to actively vary the control weighting values to attempt to find the optimal values for the current operating condition.
  • One aspect of the present invention is to introduce a time-varying control o weighting. Another aspect is to improve the re-scaling of the actuator commands in the event of actuator saturation.
  • variable control weighting The approach used to achieve a time-varying control weighting in the noise and 5 vibration control algorithm, denoted as variable control weighting, is as follows.
  • the control weightings are set to some initial conservative values.
  • the algorithm slowly varies the control weighting on a channel-by-channel basis until optimal performance is achieved.
  • optimal performance is defined as achieving the o greatest reduction in the magnitude of the sensor signals z without saturating any of the actuator channels.
  • values of the actuator commands are used to actively adjust the control weighting values to maximize the reductions in the sensor signals while avoiding saturating any of the actuators.
  • variable control weighting approach In a steady-state condition, the variable control weighting approach actively seeks for each actuator channel the smallest value of control weighting required to prevent saturation. However, recognizing the fact that a helicopter in flight is never truly in a steady-state condition, the variable control weighting approach actively increases the value of the control weighting for any actuator channel that saturates.
  • the approach used in the noise and vibration control algorithm is to introduce various threshold levels, and multiply the control weighting (W U)1 ) k for each actuator i at each time step k by a scalar based on the magnitude of the control command (u,) k computed for that actuator.
  • W U control weighting
  • the actual numbers used would differ for each specific application and would depend upon many different factors, including the update rate and the control bandwidth.
  • the performance metric of interest is not the rms of all sensors, but rather the worst case.
  • the weighting matrix W z is used to place differential weighting on various sensors in which it is desired to produce reductions.
  • the relative values of the elements of W z can be actively adjusted such that all sensors are below their maximum allowable values.
  • the relative values in the (typically diagonal) W z matrix are adjusted such that the trace of the matrix remains unchanged but the element corresponding to the sensor which is above the desired specification is increased. This is done iteratively until all are below the desired specification.
  • the nominal updated control step is given by
  • u k+! u k - ⁇ (T k H W z T k + W u + W ⁇ uV'CWuUk + Tk H W z z k ) 5
  • the notation u(i) k indicates the i th element of the vector a at time step k.
  • the vector e ⁇ denotes a vector with all zero entries except for unity in the i th entry, so that the new control weighting matrix differs from the original matrix only in the i l diagonal entry. If there are multiple actuators at saturation (L>1), then additional terms are added to W u . 5 Solving for ⁇ k+ ⁇ for each actuator channel j yields
  • the scalar Y(j,i) refers to the (j,i) th element of the matrix Y defined earlier.
  • ⁇ being a real diagonal matrix of additional control weights, i representing a vector of indices corresponding to the saturated actuators, and Y(j,i) a lxL vector. From this equation, then given ⁇ , ⁇ (i)k+ ⁇ can be computed. From this, the remaining elements of ⁇ k+ ⁇ can be computed.
  • ⁇ Y(i,i):
  • a( ⁇ y) 2 + 2b( ⁇ y) + c 0
  • a (l- ⁇ ) 2
  • variable control weighting The scaling formulation described herein can be used in conjunction with the previously described variable control weighting approach.
  • the final line of the table given in the variable control weighting section is modified to use the updated control weighting based on ⁇ .
  • This approach results in optimal performance in the presence of actuator saturations. Without this additional modification, the variable control weighting described earlier will eventually converge to the optimal performance solution, however, the convergence may be poor. Note that if none of the actuators saturate in any conditions, then the actuators have more authority than they need. Hence, if the actuators must be designed so as to never saturate in order to ensure good performance, then the overall cost and weight of the system will be excessive.
  • the appropriate control weight for that actuator is computed and can be used in the next step. Also, for large n a , the computations required for the approach described below are substantially more than those required for the first approach.
  • the second approach is guaranteed to converge if there are multiple actuator saturations. Therefore, the most appropriate algorithm for a particular application depends on the number of actuators, the computation available, and the extent to which multiple actuators are frequently operating at their saturation limits. The second approach, described below, is described in more detail and claimed in copending U.S. Application Serial Number , filed , and also claims prior to U.S. Serial Number
  • a nominal updated control step is given by:
  • ⁇ is "a large number" (i.e., on the order of 10 6 times larger than the magnitude of a typical element of W ⁇ u .)
  • the vector e denotes a vector with all zero entries except for unity in the i th entry, so that the new control rate weighting matrix differs from the original matrix only in the i th diagonal entry.
  • FIG. 2 shows a perspective view 20 of a vehicle 118 in which the present invention can be used.
  • Vehicle 118 which is typically a helicopter, has rotor blades 119 (a)...(d).
  • Gearbox housing 110 is mounted at an upper portion of vehicle 118.
  • Gearbox mounting feet 140 (a)...(c) (generally 140) provide a mechanism for affixing gearbox housing 110 to vehicle airframe 142.
  • Sensors 128(a) through (d) (generally 128) are used to sense acoustic vibration produced by the vehicle, which can be from the rotorblades 119 or the gearbox housing 110. Although only four sensors are shown, there are typically any suitable number of sensors necessary to provide sufficient feedback to the controller (not shown).
  • the sensors 128 may be mounted in the vehicle cabin, on the gearbox mounting feet 140, or to the airframe 142, or to another location on the vehicle 118 that enables vehicle vibrations or acoustic noise to be sensed.
  • Sensors 128 are typically microphones, accelerometers or other sensing devices that are capable of sensing vibration produced by gear clash from the gearbox 110 and generating a signal as a function of the sensed vibration. These sensors generate electrical signals (voltages) that are proportional to the local noise or vibration.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Feedback Control In General (AREA)

Abstract

L'invention concerne un procédé et un système qui réduisent les bruits ou vibrations indésirables dans un véhicule. L'ambiance vibratoire est mesurée et des signaux de commande sont générés sur une certaine durée. Les signaux de commande sont générés en fonction de la vibration mesurée et en fonction d'une pondération du contrôle. La variation de la pondération du contrôle permet d'obtenir les meilleurs résultats possible soumis à des limitations de saturation.
PCT/US2002/005845 2002-02-27 2002-02-27 Dispositif efficace de calcul permettant d'effectuer un controle optimal au moyen de limitations de controle WO2003073415A1 (fr)

Priority Applications (1)

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AU2002244172A AU2002244172A1 (en) 2002-02-27 2002-02-27 Computationally efficient means for optimal control with control constraints

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US27179202P 2002-02-27 2002-02-27

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1837862A1 (fr) * 2006-03-24 2007-09-26 Eurocopter Procédé et dispositif de traitement du bruit à bord d'un aeronef
EP2667380A3 (fr) * 2012-05-22 2014-02-26 Honda Motor Co., Ltd. Appareil de contrôle de bruit actif
EP2725575A1 (fr) 2012-10-23 2014-04-30 Airbus Helicopters Procédé et dispositif actif de traitement de bruit à bord d'un véhicule, et véhicule muni d'un tel dispositif
US20150097074A1 (en) * 2013-10-03 2015-04-09 Sikorsky Aircraft Corporation Dual-frequency active vibration control

Citations (4)

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Publication number Priority date Publication date Assignee Title
US5386472A (en) * 1990-08-10 1995-01-31 General Motors Corporation Active noise control system
US5526292A (en) * 1994-11-30 1996-06-11 Lord Corporation Broadband noise and vibration reduction
EP0773531A2 (fr) * 1995-11-07 1997-05-14 DIGISONIX, Inc. Système de commande actif et adaptatif à sélection de fréquence
US6094601A (en) * 1997-10-01 2000-07-25 Digisonix, Inc. Adaptive control system with efficiently constrained adaptation

Patent Citations (4)

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Publication number Priority date Publication date Assignee Title
US5386472A (en) * 1990-08-10 1995-01-31 General Motors Corporation Active noise control system
US5526292A (en) * 1994-11-30 1996-06-11 Lord Corporation Broadband noise and vibration reduction
EP0773531A2 (fr) * 1995-11-07 1997-05-14 DIGISONIX, Inc. Système de commande actif et adaptatif à sélection de fréquence
US6094601A (en) * 1997-10-01 2000-07-25 Digisonix, Inc. Adaptive control system with efficiently constrained adaptation

Non-Patent Citations (1)

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Title
MELTON D E ET AL: "Adaptive feedforward multiple-input, multiple-output active noise control", DIGITAL SIGNAL PROCESSING 2, ESTIMATION, VLSI. SAN FRANCISCO, MAR. 23 - 26, 1992, PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH AND SIGNAL PROCESSING (ICASSP), NEW YORK, IEEE, US, vol. 5 CONF. 17, 23 March 1992 (1992-03-23), pages 229 - 232, XP010058818, ISBN: 0-7803-0532-9 *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1837862A1 (fr) * 2006-03-24 2007-09-26 Eurocopter Procédé et dispositif de traitement du bruit à bord d'un aeronef
FR2899011A1 (fr) * 2006-03-24 2007-09-28 Eurocopter France Procede et dispositif de traitement du bruit a bord d'un aeronef
EP2667380A3 (fr) * 2012-05-22 2014-02-26 Honda Motor Co., Ltd. Appareil de contrôle de bruit actif
EP2725575A1 (fr) 2012-10-23 2014-04-30 Airbus Helicopters Procédé et dispositif actif de traitement de bruit à bord d'un véhicule, et véhicule muni d'un tel dispositif
US9305541B2 (en) 2012-10-23 2016-04-05 Airbus Helicopters Method and an active device for treating noise on board a vehicle, and a vehicle provided with such a device
US20150097074A1 (en) * 2013-10-03 2015-04-09 Sikorsky Aircraft Corporation Dual-frequency active vibration control

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