JP2010202081A - Active vibration and noise control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an active vibration and noise control device capable of continuing a noise reduction control without giving a sense of incongruity even if an environment around a structure such as the state of a road surface on which a vehicle travels is changed. <P>SOLUTION: A plurality of acceleration sensors 10a-10d and actuators 20a, 20b which apply wave motion into a cabin are installed in the cabin. A control instruction value calculation part 32 is provided to control the outputs of the actuators 20a, 20b so that the noise in the control space 100 inside the cabin can be reduced according to the output signals of the acceleration sensors 10a-10d. When the frequency characteristics of the output signals of the acceleration sensors 10a-10d are varied, the control instruction value calculation part 32 controls the outputs of the actuators 20a, 20b so that the noise in the control space nears desired frequency characteristics. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technique for reducing noise generated in a structure such as a vehicle by outputting a wave.

  Conventionally, a noise control device and a noise control method have been proposed that measure noise generated as a vehicle travels in a vehicle cabin and generate sound waves that cancel the noise to reduce noise. For example, a plurality of vibration detection means for detecting the vibration of the vehicle body of the vehicle are provided, and an actuator such as a speaker or a vibrator installed in the vehicle is operated based on the detected vibration of the vehicle body to reduce the noise in the vehicle interior. A noise control device has been proposed (see Patent Document 1).

Japanese Patent Laid-Open No. 8-2922771

  However, when the noise control device described in Patent Document 1 described above is used, since the control using the adaptive filter is performed, the frequency characteristics of the noise during the control cannot be freely designed. Therefore, when the road surface on which the vehicle travels changes, the effect of noise reduction control in a desired frequency band cannot be sufficiently obtained, and there is a possibility that the passenger may feel uncomfortable due to a change in noise quality. there were.

  The present invention has been made to solve such a conventional problem, and the object of the present invention is to feel uncomfortable even when the surrounding environment of the structure such as a road surface on which the vehicle travels changes. It is to continue noise reduction control.

  The present invention is based on a sensor disposed on a structure for detecting vibration of the structure, a wave applying means for applying a wave to a space or structure in the structure, and an output signal of the sensor. Control means for controlling the wave applying means so as to reduce noise in the control space. Then, when the reference noise corresponding to the frequency of the output signal of the sensor changes, the control means adjusts the output from the wave applying means so as to approach the reference noise.

  In the present invention, even when a change in the surrounding environment of a structure (for example, a vehicle) occurs and the frequency characteristic of the sensor signal changes, the wave application unit is driven by appropriately adjusting parameters used in the control unit. Therefore, the noise inside the structure can be reduced without a sense of incongruity.

It is explanatory drawing which shows the outline of the active vibration noise control apparatus which concerns on this invention, (a) shows the whole vehicle, (b) shows the tire periphery. It is a block diagram which shows the structure of the active vibration noise control apparatus which concerns on this invention. It is a block diagram which shows the detailed structure of the control command value calculation part of the active vibration noise control apparatus which concerns on 1st Embodiment of this invention. It is a flowchart which shows the process sequence by the control command value calculation part of the active vibration noise control apparatus which concerns on 1st Embodiment of this invention. It is a block diagram which shows the detailed structure of the switching instruction | indication part of the active vibration noise control apparatus which concerns on 1st Embodiment of this invention. It is a flowchart which shows the process sequence by the switching instruction | indication part of the active vibration noise control apparatus which concerns on 1st Embodiment of this invention. It is a flowchart which shows the process sequence by the controller of the active vibration noise control apparatus which concerns on 1st Embodiment of this invention. It is a block diagram which shows the structure which recalculates the filter coefficient used with a controller of the active vibration noise control apparatus which concerns on 1st Embodiment of this invention. FIG. 4 is a frequency characteristic diagram of noise generated when the vehicle travels on a road surface A according to the first embodiment of the present invention. FIG. 4 is a frequency characteristic diagram of noise generated when the vehicle travels on road surfaces A and B according to the first embodiment of the present invention. FIG. 5 is a frequency characteristic diagram of noise generated when the vehicle travels on a road surface B according to the first embodiment of the present invention. FIG. 5 is a frequency characteristic diagram of noise generated when the vehicle travels on a road surface B according to the first embodiment of the present invention. It is a block diagram which shows the detailed structure of a controller of the active vibration noise control apparatus which concerns on 2nd Embodiment of this invention. It is a flowchart which shows the process sequence by the controller of the active vibration noise control apparatus which concerns on 2nd Embodiment of this invention. It is a block diagram which shows the structure which recalculates the filter coefficient used with a controller of the active vibration noise control apparatus which concerns on 2nd Embodiment of this invention. It is a block diagram which shows the detailed structure of the switching instruction | indication part of the active vibration noise control apparatus which concerns on 3rd Embodiment of this invention. It is a flowchart which shows the process sequence by the switching instruction | indication part of the active vibration noise control apparatus which concerns on 3rd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Typical causes of vehicle interior noise entering from the outside of the vehicle (structure) are engine noise caused by engine vibration and noise caused by road surface unevenness entering from tires during driving ( Hereinafter, it is referred to as road noise), and there is a wind noise generated by the air flow during traveling. In the present embodiment, reduction of road noise will be mainly described from the above noises.

  FIG. 1 is an explanatory diagram schematically showing main propagation paths of vehicle body vibration and road noise caused by road surface unevenness when the vehicle is traveling. FIG. FIG. 1B is a side view of the tire 200. FIG.

  As shown in FIG. 1 (a), vibrations that are the main components of road noise entering the vehicle body from the four tires 200 are first attached to the axle 120 and suspension 130 shown in FIG. 1 (b) (not shown). The member 140 enters a highly rigid beam-like member called a member 140. Thereafter, the vibration propagates to the floor panel 110, which is a plate member having a relatively low rigidity and surrounded by the member 140, and the floor panel 110 vibrates.

  Furthermore, the vibration of the floor panel 110 causes air vibrations in the passenger compartment and causes a resonance phenomenon in the passenger compartment, so that road noise can be heard in a predetermined space 100 in the passenger compartment. In this embodiment, in order to avoid complexity, only the space 100 (control space in the structure) near the right ear of the driver's seat is handled as the noise reduction control space.

  When a plurality of seats or a plurality of ear spaces are used as the control space, the setting may be changed as appropriate. Although noise is also generated when the roof panel and window glass (both not shown) vibrate in addition to the floor panel 110, most of the road noise that enters mainly from the attachment portion of the suspension 130 is generated by the floor panel 110. It is known to be caused by vibration. For this reason, if noise control is performed so as to cancel road noise caused by vibration of the floor panel 110, road noise can be reduced.

  In the present invention, a sensor (acceleration sensor 10 to be described later) is arranged on the floor panel 110, vehicle interior noise is estimated based on the output signal of this sensor, and a control command value is generated by the control command value generating means. Based on this control command value, a method is adopted in which control sound generated by an actuator (wave application unit) provided on the floor panel 110 is input into the passenger compartment.

  Here, the present invention uses a method of estimating the noise of the control space 100 from the signal of the acceleration sensor 10 without using a microphone as a sensor. Since the acceleration sensor 10 installed on the floor panel 110 or the member 140 is used, road noise caused by the floor panel 110 is handled as a control target. Here, the reason why the floor panel 110 or the member 140 is selected as the installation location of the acceleration sensor 10 is that coherence with the vehicle interior noise (definition will be described later) is high.

  In addition, since all noises generated from the floor panel 110 and the member 140 are included as control targets, part of the engine noise and wind noise generated by the air flowing through the bottom of the vehicle body can be handled in the same manner.

  Further, the scope of the effect of the present invention is not limited to the category of noise reduction due to vibration of the floor panel 110, but is generated by the same mechanism such as a dash panel, a front glass, and a roof panel (both not shown). The same effect can be obtained for the noise generation source if the present invention is applied to the part concerned.

  FIG. 2 is an explanatory diagram schematically showing the configuration of the active vibration noise control device according to the first embodiment of the present invention. As shown in FIG. 2, the active vibration noise control apparatus according to the present embodiment includes four acceleration sensors 10a, 10b, 10c, 10d (hereinafter referred to as individual) for measuring vibrations of the floor panel 110 and the member 140. If there is no need to distinguish between the two actuators 20a and 20b (hereinafter referred to as "acceleration sensor 10") as two wave applying means for applying vibration to the floor panel 110 or the member 140 If there is no such signal, it is referred to as “actuator 20”.) Based on the acceleration signal detected by the acceleration sensor 10, a control command value for reducing vehicle interior noise is calculated, and the control device main body 30 that controls the actuator 20 is obtained. I have.

  Here, in this embodiment, a piezo-electric actuator is used as an example of the actuator 20. Moreover, it is also possible to use an actuator installed in a part such as a dash panel, a front glass, a door panel, and further a roof panel, without adopting a form installed on the floor panel 110 or the member 140. Furthermore, a speaker installed in the vehicle compartment can be used as an actuator.

  An input signal of the control device main body 30 is an output of each acceleration sensor 10, and an output signal is a control command signal output to the actuator 20.

  A sufficient number of actuators 20 are attached to appropriate positions on the floor panel 110 of the vehicle body in order to reduce noise in the control space 100.

Generally, the number of acceleration sensors 10 needs to be larger than the number of vibration sources. The specific number of acceleration sensors 10 and their installation positions are such that the coherence Cxy (ω) between each acceleration sensor 10 and the sound pressure of noise in the control space 100 expressed by the following equation (1) is sufficiently high. (For example, 0.9 or more).

  In the present embodiment, the number of acceleration sensors is four (10a, 10b, 10c, 10d), and the number of actuators is two (20a, 20b). In addition, the number of the acceleration sensors 10 and the actuators 20 can be appropriately set to an arbitrary number.

  In the above equation (1), Pxy (ω) represents a cross power spectrum between acceleration and sound pressure, and Pxx (ω) and Pyy (ω) represent auto power spectra of acceleration and sound pressure, respectively. PH represents a Hermitian transpose matrix of P.

  The control device body 30 includes an amplification unit 31 (31a to 31f) for signal amplification and a control command value calculation unit 32 that calculates and outputs a control command value for reducing vehicle interior noise.

  When the acceleration sensor 10 is a so-called charge type, the amplifying units 31a to 31f perform conversion between charge and voltage.

  FIG. 3 is a block diagram showing a detailed configuration of the control command value calculation unit 32 shown in FIG. As shown in FIG. 3, the control command value calculation unit 32 includes an A / D conversion unit 33, a switching instruction unit 34, a vibration propagation characteristic model 70, a controller 38, and a D / A conversion unit 39. .

  The A / D converter 33 converts the acceleration signals α1, α2, α3, and α4 detected by the acceleration sensor 10 (10a to 10d) and amplified by the amplifiers 31a to 31d into digital signals, and outputs them to the subtractor 35a. To do.

  The vibration propagation characteristic model 70 is a model of a transfer function when vibration generated by the actuator 20 goes around to the acceleration sensor 10. Usually kept in memory in the form of an IIR filter for online processing. When a plurality of sensors and actuators are provided (in this embodiment, four acceleration sensors and two actuators), a filter corresponding to the number is held. In the vibration propagation characteristic model 70, a vibration generated by the actuator 20 at the installation position of the acceleration sensor 10 is calculated by multiplying the control command signal u by a model from the actuator 20 to SPL * (noise level; Sound Pressure Level). .

  The subtractor 35 a subtracts vibration generated by the actuator 20 at the installation position of the acceleration sensor 10 from the acceleration signals α <b> 1 to α <b> 4 detected by the acceleration sensor 10. The signal obtained as a result is only the signal αd (hereinafter referred to as “subtraction signal”) which is a component entered from the outside of the vehicle among the vibrations detected by the acceleration sensor 10.

  Based on the subtraction signal αd output from the subtractor 35a, the switching instruction unit 34 generates a switching instruction signal δ for determining whether or not the parameter used for the calculation of the control command signal u is to be switched by the controller 38. To the controller 38. When the switching instruction signal δ is a signal indicating that the parameter is switched, the parameter after switching is output to the controller 38 together with the switching instruction signal δ.

  The controller 38 calculates a control command signal u to be output to the actuator 20 in order to reduce noise in the control space 100 based on the subtraction signal αd output from the subtractor 35a.

  The D / A conversion unit 39 converts the control command signal u calculated by the controller 38 into an analog signal, and outputs the control command signal u converted into the analog signal to the amplification units 31e and 31f shown in FIG. In the present embodiment, the control command value calculation unit 32 is mounted on a so-called CPU.

  Next, a processing procedure in the control command value calculation unit 32 will be described with reference to the flowchart shown in FIG.

  First, in step S11, acceleration signals α1 to α4 converted into digital signals by the A / D conversion unit 33 are input to the subtractor 35a. Thereafter, the flow proceeds to step S12.

  In step S12, the control command signal u output from the controller 38 one step before is multiplied by the filter of the vibration propagation characteristic model 70, and a signal obtained by the multiplication is output to the subtractor 35a. Thereafter, the flow proceeds to step S13.

  In step S13, the subtractor 35a subtracts the signal obtained in the process in step S12 from each acceleration signal α1 to α4 obtained in the process in step S11. Thereafter, the flow proceeds to step S14.

  In step S <b> 14, the switching instruction unit 34 determines whether or not to switch the parameter used by the controller 38, and further executes processing for calculating the parameter after switching. If it is determined that the parameter is to be switched, the parameter after switching is output. Details of this processing will be described later with reference to the flowchart shown in FIG. Thereafter, the flow proceeds to step S15.

  In step S15, the controller 38 uses the subtraction signal αd output from the subtractor 35a, the switching instruction signal δ and the parameter output from the switching instruction unit 34, and control for reducing noise in the control space 100. The command signal u is calculated. Details of this processing will be described later with reference to the flowchart shown in FIG. Thereafter, the flow proceeds to step S16.

  In step S16, the D / A converter 39 converts the control command signal u output from the controller 38 into an analog signal and outputs the analog signal to the outside.

  FIG. 5 is a block diagram showing a flow of processing of the switching instruction unit 34 shown in FIG. 3 (processing in step S14 of FIG. 4). As illustrated in FIG. 5, the switching instruction unit 34 includes a PS (power spectrum) calculation unit 51, a PS holding unit 52, an update determination unit 37, and a parameter update unit 41.

  The PS calculation unit 51 calculates the power spectrum Sα of the subtraction signal αd output from the subtractor 35a shown in FIG.

  The PS holding unit 52 stores the power spectrum Sα ′ of the subtraction signal αd output one step or more before. When the update determination unit 37 determines that the subtraction signal αd has changed (when the reference noise corresponding to the frequency of the sensor output signal fluctuates), it is stored in the PS calculation unit 51. The existing power spectrum Sα ′ is overwritten with new data. When it is determined that the subtraction signal αd does not change (when the reference noise corresponding to the frequency of the sensor output signal has not changed), the previous data is retained.

  The update determination unit 37 changes the parameter used by the controller 38 based on the current power spectrum Sα output from the PS calculation unit 51 and the power spectrum Sα ′ one step or more before output from the PS holding unit 52. It is determined whether to perform the determination, and the determination result is output to the parameter update unit 41.

  In the parameter update unit 41, the determination result in the update determination unit 37 is acquired, and when the parameter is updated, a new parameter is configured based on the current power spectrum Sα, and the reference corresponding to the frequency of the output signal of the sensor 3 is output to the controller 38 shown in FIG. On the other hand, when the parameter is not updated, a flag signal indicating that the parameter is not updated is output to the controller 38.

  Next, the calculation process of the switching instruction signal shown in step S14 of FIG. 4 will be described with reference to the flowchart shown in FIG.

  In step S21, the PS calculation unit 51 calculates the power spectrum Sα of the subtraction signal αd input to the switching instruction unit 34. For example, the power spectrum can be calculated using the periodogram method or the Welch method for the subtraction signal αd input at every calculation cycle. Thereafter, the flow proceeds to step S22.

  In step S22, the current power spectrum Sα calculated in the process of step S21 and the power spectrum Sα ′ of one or more steps held in the PS holding unit 52 are input to the update determination unit 37. And the update determination part 37 determines whether the parameter used with the controller 38 shown in FIG. 3 is updated by contrasting two power spectrum S (alpha) and S (alpha) '. For example, the correlation coefficient of these two power spectra Sα is obtained in a predetermined frequency band, and the parameter is updated when the correlation coefficient is not more than a predetermined value, and the parameter is not updated when the correlation coefficient is not less than the predetermined value. . That is, when the frequency of the output signal of the acceleration sensor 10 fluctuates, the parameters are updated so that the noise level in the control space 100 approaches a desired frequency. Further, a correlation coefficient between the frequency characteristic of each acceleration sensor 10 and the frequency characteristic of the acceleration signal actually detected by each acceleration sensor 10 is obtained, and when this correlation coefficient is a predetermined value or less, the controller 38 If the parameter is updated, the parameter can be changed quickly and the fluctuation of the noise level can be suppressed.

  Further, a correlation coefficient between the frequency characteristic of the estimated noise held in advance and the newly acquired estimated noise is obtained, and when the correlation coefficient becomes a predetermined value or less, the parameter of the controller 38 is updated. By performing the above, it is possible to discriminate with one index in the entire frequency band to be controlled, the parameter update is shortened, and the uncomfortable feeling due to the change in the noise reduction control can be reduced.

  In addition, since there are a plurality of acceleration signals, the above calculation is performed on the correlation coefficients of all the acceleration signals. If the parameter is updated, the flow proceeds to S24. If the parameter is not updated, the flow proceeds to S23.

  In step S23, a flag signal indicating that the parameter is not updated is output to the parameter updating unit 41. Thereafter, the parameter update unit 41 ends the flow without updating the parameters used by the controller 38.

  On the other hand, in step S24, the value of the data held in the PS holding unit 52 (power spectrum Sα ′ before one step or more) is updated to the latest value of the power spectrum Sα output from the PS calculation unit 51. Thereafter, the flow proceeds to S25.

  In step S <b> 25, the parameter update unit 41 updates parameters used by the controller 38. In the present embodiment, a transfer function representing an outline of the power spectrum Sα obtained by the PS calculation unit 51 is used as a parameter. In this process, a transfer function obtained by fitting the power spectrum Sα obtained by the PS calculation unit 51 with a predetermined order is calculated. For example, the method described in “Adachi,“ System Identification for Control ”, Tokyo Denki University Press, 1996” can be used to calculate the transfer function. When the parameters are updated, the updated parameters are output to the controller 38 shown in FIG. 3, and the flow is terminated.

  Here, in the process of step S22 described above, since it is determined whether or not the parameter is updated using the correlation coefficient, this determination is performed for the entire frequency band to be controlled and with one index. Can be adjusted online.

  In the present embodiment, in step S25, a transfer function representing the outline of the power spectrum Sα obtained by the PS calculation unit 51 is used as a parameter. In addition, it is also possible to determine the outline of the acceleration power spectrum in advance and use only the peak frequency and attenuation coefficient as parameters. In this case, it can obtain | require by estimating those parameters from the power spectrum data obtained now. That is, the parameter can be set so that the effect of the noise reduction control at the peak frequency is enhanced in accordance with the fluctuation of the peak frequency of the noise in the passenger compartment estimated based on the detection signal of the acceleration sensor 10. In this case, the noise reduction control can be performed following the fluctuation of the peak frequency of the noise.

  Further, according to the fluctuation of the noise level at the peak frequency of the noise in the passenger compartment estimated based on the detection signal of the acceleration sensor 10, it is possible to set the parameter so that the noise level at the peak frequency does not fluctuate. . In this case, noise reduction control can be performed following the peak level of noise.

  Furthermore, a band pass filter having a pass band in the control band can be used as a parameter. With this method, it is possible to change the frequency band to be controlled when the maximum frequency and the minimum frequency of the acceleration signal change. In this case, the upper and lower limits of the frequency band in which the power spectrum of the acceleration signal is equal to or greater than a predetermined value are examined, and the bandpass filter can be updated as a parameter by setting the value as the cutoff frequency of the bandpass filter. That is, the parameter can be set so that the noise level in the frequency band of the peak width does not fluctuate in accordance with the peak width of the noise in the passenger compartment estimated based on the detection signal of the acceleration sensor 10. In this case, even when the peak width of noise to be controlled fluctuates, the control frequency band of the control command value calculation unit 32 can be changed, and noise reduction control can be performed efficiently.

  Further, when the noise level in the passenger compartment estimated based on the acceleration signal α detected by each acceleration sensor 10 is different from a preset maximum frequency (a frequency higher than a predetermined noise level), the parameter of the controller 38 is set. Since the control frequency band of the controller 38 can be changed when the frequency band to be controlled fluctuates, the noise reduction control can be performed effectively.

  Next, the calculation process of the control command signal u by the controller 38 shown in step S15 of FIG. 4 will be described with reference to the flowchart shown in FIG.

  In step S31, the switching instruction signal δ, which is the output of the switching instruction unit 34, is input. Thereafter, the flow proceeds to S32.

  In step S32, it is determined whether or not the input switching instruction signal δ is a signal for instructing parameter switching. If it is a signal for instructing switching, the flow proceeds to step S33, and if it is not a signal for instructing switching, the flow proceeds to step S34.

  In step S33, a filter used in the controller 38 is updated by a method described later using the new parameter input as the switching instruction signal δ. Thereafter, the flow moves to step S34.

  In step S34, the subtraction signal αd output from the subtractor 35a is filtered to calculate the control command signal u. Thereafter, the flow proceeds to step S35.

  In step S35, the control command signal u obtained by the process of step S34 is output to the D / A conversion unit 39, and then the flow ends.

  FIG. 8 is a block diagram used for obtaining the filter used in the controller 38 (the processing in step S33 described above). A block 42 (denoted as C in FIG. 8) shown in FIG. 8 represents a control command value generation filter to be designed, and a block 50 (denoted as Gα in FIG. 8) represents noise in the control space 100 from the subtraction signal αd during traveling. It represents the transfer function up to the level (SPL *). A block 60 (indicated as Gp in FIG. 8) represents a transfer function from the control command signal u output to the actuator 20 to the noise level (SPL *) in the control space 100.

  In FIG. 8, a single signal line is shown, but when there are a plurality of accelerations, control spaces 100, and actuators 20, a plurality of signal lines corresponding to the number of the signal lines are shown. In that case, each block is a multi-input, multi-output block.

  Blocks 45a (denoted as Wc3 in FIG. 8) and 45b (denoted as Wc4 in FIG. 8) are weight functions used as design parameters. The weight function Wc3 of the block 45a has a frequency characteristic of acceleration input during traveling. As a result, the effect of noise reduction control can be further enhanced at a frequency with a large noise level.

  That is, a plurality of parameters corresponding to the frequency characteristics of each acceleration sensor 10 (10a to 10d) are stored in advance, and the frequency characteristics of the acceleration signal α (α1 to α4) actually detected by each acceleration sensor 10 are the most. If the configuration is such that the control command signal u is calculated by selecting a suitable parameter, the noise level can be reduced quickly in response to a change in frequency.

  The weight function Wc4 of the block 45b is used to limit the maximum voltage of the control command signal u. When the value of the weight function Wc4 is increased, the gain of the corresponding actuator 20 is decreased. This weight function Wc4 can also have frequency characteristics in the same manner as Wc3. In this case, the gain can be reduced only in a certain frequency band.

  The weight function Wc3, Wc4 of each block 45a, 45b uses a mathematical model expressed by differential equations or Laplace transform. This modeling may be performed as follows.

  The transfer function Gp of the block 60 is a system identification using a sound pressure signal and an input signal in the control space 100 determined according to the occupant position obtained by inputting white noise or an impulse signal to the actuator 20. Can be obtained. The method of system identification is, for example, a part described in “Structural Dynamical Toolbox” which is a tool box of the control system design tool MATLAB and the document “Adachi,“ System Identification for Control ”, Tokyo Denki University Press, 1996”. A spatial identification method may be used.

  The transfer function Gα shown in the block 50 can be obtained by measuring the acceleration signal and noise level during traveling and using the above method.

  At this time, a filter C (block 42) is designed to minimize the transfer function from the subtraction signal αd to the noise level SPL * and the norm of the transfer function from the subtraction signal αd to the control command signal u. Various design methods can be considered. For example, design using the H∞ control method or H2 control method described in “Hosoe, Araki,“ Control System Design—H∞ Control and its Applications ”, Asakura Shoten, 1994”. can do.

  In this embodiment, the filter C is designed using the two weight functions Wc3 and Wc4 shown in the blocks 45a and 45b. However, the filter C may be designed using a design parameter (weight function) other than the reference document.

  When the transfer function Gα shown in the block 50 and the transfer function Gp shown in the block 60 are modeled as a continuous time system, the obtained filter is discretized using a Tustin transform or the like. Alternatively, each transfer function Gα, Gp may be modeled as a discrete time system, and a digital controller may be designed using a design method for the discrete time system.

  In step S33 shown in FIG. 7, the filter C of the block 42 is updated by a parameter update signal obtained from the switching instruction unit 34 in accordance with a change in road surface condition.

  The update method may be performed as follows. First, a low-dimensional transfer function approximating the power spectrum Sα of the acceleration signal after fluctuation is used as a parameter, and this information is output from the switching instruction unit 34 to the controller 38.

  Next, the controller 38 reflects this information in the weighting function Wc3 shown in the block 45a, and recalculates the filter C of the block 42 shown in FIG. 8 by the above procedure along with the filtering process in each step. After recalculation, the noise reduction control adapted to the current road surface condition can be realized by updating the filter C by interruption processing.

  Further, by defining in advance the outline and order of the frequency characteristics of the acceleration signal α (α1 to α4) detected by the acceleration sensor 10, and using the peak frequency and attenuation coefficient as parameters, the parameter signal is obtained. It is also possible to redesign the filter C of the block 42 for these variations.

  That is, at least one of the peak frequency and the attenuation coefficient of the acceleration signal α (α1 to α4) detected by each acceleration sensor 10 is used as a feature amount, and a plurality of parameters corresponding to the feature amount are stored in advance. In addition, it is possible to select a parameter that matches the feature quantity of the acceleration signal actually detected by the acceleration sensor 10. In this case, the parameters of the controller 38 can be adjusted in a short time according to the peak frequency and the attenuation coefficient, and the noise felt by the occupant can be reduced. Further, parameters other than the peak frequency and the attenuation coefficient can be selected in some form as long as they are feature quantities of the acceleration signal α.

  Furthermore, when at least one of the peak frequency and the attenuation coefficient of the acceleration signal α (α1 to α4) detected by each acceleration sensor 10 is used as a feature value, and the feature value is different from a previously held value Furthermore, if the parameters of the controller 38 are adjusted, the noise reduction control can be promptly dealt with with respect to fluctuations in the peak frequency or attenuation coefficient, and the generation of unpleasant noise can be suppressed.

  Further, at least one of the noise peak frequency and the attenuation coefficient estimated based on the acceleration signal α (α1 to α4) detected by each acceleration sensor 10 is used as a feature amount, and the feature amount is If the parameter of the controller 38 is adjusted when the value is different from the value held in advance, the noise reduction control can be dealt with quickly with respect to the fluctuation of the estimated noise peak frequency or attenuation coefficient, which is uncomfortable. Generation of noise can be suppressed.

  Thus, when the control command value is redesigned, it is possible to redesign the controller 38 having the optimum parameters for the sensor signal having the frequency characteristics currently obtained. That is, noise reduction control can be performed more efficiently by redesigning the parameters of the controller 38 using the frequency characteristics of the acceleration signal α detected by each acceleration sensor 10.

  Next, changes in the noise level when the active vibration noise control device according to the present embodiment is used will be described with reference to the characteristic diagrams shown in FIGS.

  FIG. 9 is a characteristic diagram showing the frequency characteristics of the noise level in the control space 100 when the vehicle is traveling on a certain road surface (road surface A), and the curve S1 is when noise reduction control is not performed. The noise level and the curve S2 indicate the noise level when the noise reduction control is performed. The current desired frequency characteristic is assumed to be a substantially constant value in the control frequency band.

  FIG. 10 shows the frequency characteristics of the noise level in the control space 100 when the vehicle is traveling on the road surface A described above and the road surface B different from the road surface A, and the curve S11 is a noise reduction when traveling on the road surface A. This is the noise level when the control is not performed (that is, the same as S1 in FIG. 9), and the curve S12 shows the frequency characteristic of the noise level when the noise reduction control is not performed when traveling on the road surface B. As understood from the curves S11 and S12, when traveling on the road surface B, the noise level in the band of 100 to 200 Hz is lower than when traveling on the road surface A, and conversely, in the band of 300 to 400 Hz. The noise level is high. Here, let us consider a case where the traveling road surface changes from the road surface A to the road surface B while the vehicle is traveling.

  FIG. 11 shows the frequency characteristics of the noise level in the control space 100 when the vehicle is traveling on the road surface B, the curve S21 shows the noise level when the noise reduction control is not performed, and the curve S22 shows the road surface A. The noise level when the noise reduction control is performed using the control command value set for (i.e., without changing the control command value) is shown.

  As understood from the curves S21 and S22, a sufficient noise reduction control effect is not obtained in the frequency band of 300 to 400 Hz. This is because when the traveling road surface is the road surface A, the controller 38 with a frequency of 300 to 400 Hz is assumed on the assumption that the acceleration input is smaller than an acceleration signal input to a frequency band of 100 to 200 Hz. Although the parameters were designed, it is because the necessary noise reduction cannot be obtained because the traveling road surface is changed to the road surface B.

  FIG. 12 shows the frequency characteristics of the noise level in the control space 100 when the vehicle is traveling on the road surface B, and the curve S31 does not perform the noise reduction control (that is, similar to the curve S21 in FIG. 11). The curve S32 shows the noise level when the noise reduction control is performed using the control command value corresponding to the road surface B. As understood from the curves S41 and S42, the reduction in the effect of the noise reduction control in the frequency band of 300 Hz to 400 Hz, which is a problem in the characteristic diagram shown in FIG. 11, is solved, and the desired frequency band (100 It can be seen that a sufficient noise reduction control effect is obtained at ˜400 Hz.

  As described above, in the active vibration noise control apparatus according to the first embodiment, the frequency characteristics of the output signal of the acceleration sensor 10 are changed in accordance with changes in the road surface condition on which the vehicle travels and changes in tires, structural members, and the like. Even in this case, the parameters of the controller 38 are adjusted as appropriate to adapt to this frequency. Therefore, the change in the effect of the noise reduction control can be reduced, and the discomfort of the personnel present in the vehicle can be reduced. In addition, since the control command signal u output to the actuator 20 can be changed according to the change in the output signal of the acceleration sensor 10, the actuator 20 can be used efficiently. Furthermore, since the control command signal u to be output to the actuator 20 can be obtained with the minimum amount of computation required at that time, the computation load on the computer on which the controller 38 is mounted can be reduced.

  Also, by changing the desired frequency characteristic, for example, when it is desired to reduce a certain peak, the desired frequency characteristic may be created to lower the peak. When the peak level, frequency, and attenuation coefficient change, the parameter of the controller 38 can always be set to reduce the target peak by adjusting the parameter of the controller 38 so as to follow the value.

  Furthermore, if the amount of noise reduction due to the control of the noise generated in the passenger compartment is used as a feature amount, and the feature amount is reduced by a predetermined amount, the parameter of the controller 38 is adjusted. Since fluctuations can be used as timing for direct control, generation of unpleasant noise can be suppressed.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. Since the active vibration noise control apparatus according to the second embodiment is different from the first embodiment described above only in the configuration of the controller 38 provided in the control command value calculation unit 32 shown in FIG. The configuration of the controller 38 will be described below with reference to the block diagram shown in FIG.

  As shown in FIG. 13, the controller 38 includes a first filter 42a, a second filter 42b, and a third filter 42c to which the subtraction signal αd is input, respectively, and outputs of the filters 42a, 42b, and 42c. Addition weight multiplication units 43a, 43b, 43c provided on the side. A design method of each of the filters 42a, 42b, and 42c will be described later with reference to FIG.

  An addition weight ρ1 is set in the addition weight multiplication unit 43a, an addition weight ρ2 is set in the addition weight multiplication unit 43b, and an addition weight ρ3 is set in the addition weight multiplication unit 43c. Since the subtraction signal αd is a plurality of signals, each of the addition weights ρ1, ρ2, and ρ3 is a vector quantity, and multiplication with each of the filters 42a, 42b, and 42c is multiplication for each element.

  Further, an addition weight calculation unit 44 is provided, and the addition weight calculation unit 44 calculates the addition weights ρ1, ρ2, and ρ3 in the addition weight multiplication units 43a, 43b, and 43c based on the switching instruction signal δ.

  An adder 36 is provided on the output side of each of the addition weight multiplication units 43a, 43b, and 43c. In the adder 36, a linear sum of the control command values weighted by the respective addition weight multiplication units 43a, 43b, and 43c is obtained. The control command signal u is generated by calculation.

  The addition weight calculation unit 44 calculates the addition weights ρ1, ρ2, and ρ3 in each of the addition weight multiplication units 43a, 43b, and 43c based on the switching instruction signal δ. This calculation method will be described later. In the present embodiment, an example is shown in which three filters 42a, 42b, and 42c are used and three addition weights ρ1, ρ2, and ρ3 are used. However, the number is limited to three. is not.

  Next, the processing operation of the controller 38 shown in FIG. 13 will be described with reference to the flowchart shown in FIG.

  First, in step S41, the subtraction signal αd (acceleration component entered from the outside of the vehicle) obtained by the subtraction unit 35a is input. Thereafter, the flow proceeds to step S42.

  In step S42, the switching instruction signal δ calculated by the switching instruction unit 34 is input. Thereafter, the flow proceeds to step S43.

  In step S43, the weight function θ is calculated by the addition weight calculator 44 based on the switching instruction signal δ, and the calculated θ is updated as the addition weights ρ1, ρ2, and ρ3. Thereafter, the flow proceeds to step S44.

  In step S44, the coefficients of the first filter 42a, the second filter 42b, and the third filter 42c set in advance are multiplied for each input subtraction signal αd. That is, the subtraction signal αd is filtered by the first to third filters. Thereafter, the flow proceeds to step S45.

  In step S45, the filtered signals are multiplied by the respective addition weights ρ1, ρ2, and ρ3 obtained based on the weight function θ, and added by the adder 36. At this time, when the subtraction signal αd is a vector quantity, multiplication and addition are performed for each element. Thereafter, the flow moves to step S46.

  In step S46, the signal calculated in the process of step S45 (the output signal of the adder 36) is output, and the flow ends.

  FIG. 15 is a block diagram for designing the first to third filters 42a, 42b, 42c and the addition weights ρ1 to ρ3 used in the controller 38 shown in FIG. 13, and the design procedure will be described below. To do.

  The blocks 50, 42, 60, and 45b shown in FIG. 15 are the same as the block diagram shown in FIG. A block 45a shown in FIG. 15 is a weighting function (Wc3 (θ)) that takes into account the frequency characteristics of the acceleration signal, and is expressed as a function of the parameter θ. For example, the peak frequency or attenuation coefficient of the frequency characteristic may be held as θ. Or if (theta) is defined as an offset component on a frequency characteristic, it can show by following (2) Formula.

Wc3 (θ) = θ × Sα (2)
At this time, the parameter θ is always present in affine form in Wc3. In addition, if the feature quantity of the acceleration signal exists in an affine form with respect to Wc3, it can be used as a parameter. The control system thus created is called an LPV (Linear Parameter Variant) system. The gain schedule controller C (θ) depending on the parameter θ can be obtained by using the function “hinfgs” prepared in the MATLAB Robust Control toolbox for this system. In general, when the controller at the end of the range in which the parameter can move is Ci, when the parameter is θ, the controller C (θ) can be expressed by the following equation (3).

  Here, ρ is an appropriate addition weight function including θ in a linear form. Therefore, by using Ci of the expression (3) as the filter 42 and using ρ as the addition weight function, a controller including the filter 42, the addition weight multiplication units 43a to 43c, and the adder 36 can be configured. In addition, since θ varies from moment to moment, the addition weight ρ is obtained from the parameter θ, and the addition ratio of the controller can be changed to perform control corresponding to the road surface condition online.

  Further, if the peak level, frequency, and attenuation coefficient are held as parameters, control can be performed by following them online. That is, the peak frequency of the acceleration signal α (α1 to α4) detected by each acceleration sensor 10 (10a to 10d) and at least one of the feature amounts or the plurality of frequency characteristics stored in advance for each of the attenuation characteristics. Of the parameters, the control command signal u can be adjusted and the fluctuation of the noise level can be suppressed by calculating the linear sum of the parameters close to the feature amount or the frequency characteristic. In this case, the controller 38 can be adjusted online only by calculating a linear sum of preset parameters, and the noise reduction effect can be enhanced.

  In addition, when a moving vehicle is a target, if the speed signal is used as a parameter and the fluctuation of the sensor signal corresponding to the speed is held in advance, the control command signal u can be adjusted online following the speed. .

[Third Embodiment]
Next, a third embodiment of the present invention will be described. The active vibration noise control device according to the third embodiment is different from the first embodiment described above only in the configuration of the switching instruction unit 34 provided in the control command value calculation unit 32 shown in FIG. Therefore, the configuration of the switching instruction unit 34 will be described below with reference to the block diagram shown in FIG. The switching instruction unit 34 according to the third embodiment adjusts parameters used by the controller 38 so that the effect of vibration reduction control is always maintained.

  A block 90 shown in FIG. 16 is a model of the acoustic propagation transfer function (first acoustic propagation characteristic model) from the subtraction signal αd to the noise level SPL * in the control space 100, and a block 80 is a control command signal for the actuator 20. It is a model (second acoustic propagation characteristic model) of the acoustic propagation transfer function from u to the noise level SPL * in the control space 100. The output signals of the models 90 and 80 are output to the adder 36 and added.

  The overall control effect calculation unit 53 calculates a power spectrum of the output signal of the adder 36 and then calculates an overall value in a predetermined frequency band. The update determination unit 37 and the parameter update unit 41 have the same functions as those in FIG. 5 described in the first embodiment.

  Next, a processing procedure in the switching instruction unit 34 shown in FIG. 16 will be described with reference to a flowchart shown in FIG.

  In step S51 shown in FIG. 17, the subtracted signal αd output from the subtractor 35a is input to the first acoustic propagation characteristic model 90, and the subtracted signal αd is multiplied by the first acoustic propagation characteristic model. Thereafter, the flow proceeds to step S52.

  In step S52, the control command signal u one step before output from the controller 38 is input to the second acoustic propagation characteristic model 80, and the control instruction signal u is multiplied by the second acoustic propagation characteristic model. Thereafter, the flow proceeds to step S53.

  In step S53, the signal obtained by the process of step S51 and the process of step S52 is added by the adder 36, and the estimated noise level in the control space 100 in a state where the control is performed is calculated. Thereafter, the flow moves to step S54.

  In step S54, a power spectrum is calculated from the estimated noise level using the above-described method, and an overall noise level in a predetermined frequency band is further calculated. Thereafter, the flow proceeds to step S55.

  In step S55, the update determination unit 37 determines whether or not a predetermined overall control effect set in advance is obtained, and determines whether or not to update the parameter.

  If the parameter is updated in step S56, the flow proceeds to step S57, and if the parameter is not updated, the flow ends.

  In step S57, the parameter update unit 41 updates and outputs the parameters used by the controller 38, and the flow ends. As the updating method, the method shown in the process of step S25 in FIG. 6 or the method shown in the second embodiment may be used.

  Thus, in the active vibration noise control apparatus of the third embodiment, by using the above method, the overall control effect can be used as the parameter update criterion, and a stable overall control effect can be obtained.

  As mentioned above, although the active vibration noise control apparatus of this invention was demonstrated based on embodiment of illustration, this invention is not limited to this, The structure of each part is made into the thing of the arbitrary structures which have the same function. Can be replaced.

  For example, in each of the above-described embodiments, the example of reducing the noise in the vehicle has been described. However, the present invention is not limited to the vehicle, and can be used for noise reduction control in an arbitrary closed space. Further, the present invention is applicable not only to fluctuations in acceleration signals due to differences in road surfaces, but also to cases where, for example, spare tires are mounted or the vibration propagation path of the vehicle fluctuates due to deterioration over time.

  In addition, the above-described embodiments are combined, for example, initially, the gain schedule is adjusted by the method shown in the second embodiment, but after that, when the road surface changes significantly, the first embodiment is redesigned. It is also possible.

  The present invention is extremely useful for reducing noise generated in the vehicle when the road surface on which the vehicle travels changes.

10 (10a to 10d) Acceleration sensor 20 (20a, 20b) Actuator 30 Control device body 31 (31a to 31f) Amplifying unit 32 Control command value calculation unit 33 A / D conversion unit 34 Switching instruction unit 35a Subtractor 36 Adder 37 Update determination unit 38 Controller 39 D / A conversion unit 41 Parameter update unit 42 Filter 42a First filter 42b Second filter 42c Third filter 43 Addition weight multiplication unit 44 Addition weight calculation unit 45a, 45b Weight function 50 Transfer function (Gα)
51 PS Calculation Unit 52 PS Holding Unit 53 Overall Control Effect Calculation Unit 60 Transfer Function (Gp)
70 Vibration propagation model 80 Second acoustic propagation characteristic model 90 First acoustic propagation characteristic model 100 Control space (predetermined space)
110 Floor panel 120 Axle 130 Suspension 140 Member 200 Tire

Claims (15)

A sensor arranged on the structure to detect the vibration of the structure;
A wave applying means for applying a wave to a space in the structure or the structure;
Control means for controlling the wave applying means so as to reduce noise in a control space in the structure based on an output signal of the sensor,
The control means adjusts the output by the wave applying means so as to approach the reference noise when the reference noise corresponding to the frequency of the output signal of the sensor fluctuates. Noise control device. The active vibration noise control device according to claim 1,
The wave applying means so that the effect of noise reduction control at the peak frequency is enhanced in accordance with the fluctuation of the peak frequency of noise inside the structure estimated based on the output signal of the sensor. An active vibration and noise control device characterized by adjusting the output by the control unit. In the active vibration noise control device according to claim 1 or 2,
The said control means is the said wave application means so that the noise level in the said peak frequency does not change according to the fluctuation | variation of the noise level in the peak frequency of the noise inside the said structure estimated based on the output signal of the said sensor. An active vibration and noise control device characterized by adjusting the output by the control unit. In the active vibration noise control device according to any one of claims 1 to 3,
The control means includes the wave applying means so that the noise level in the frequency band of the peak width does not change in accordance with the fluctuation of the peak width of the noise inside the structure estimated based on the output signal of the sensor. An active vibration and noise control device characterized by adjusting the output by the control unit. In the active vibration noise control device according to any one of claims 1 to 4,
The control means uses at least one of a peak frequency and an attenuation coefficient of the output signal of the sensor as a feature amount, and holds a plurality of parameters corresponding to the feature amount in advance, and obtains it from the output signal of the sensor An active vibration noise control apparatus characterized by selecting the parameter most adapted to the feature quantity and adjusting the output of the wave applying means. In the active vibration noise control device according to any one of claims 1 to 4,
The control means holds in advance a plurality of parameters corresponding to the frequency characteristics of the output signal of the sensor, selects a parameter that is most suitable for the frequency characteristics acquired from the output signal of the sensor, and outputs by the wave applying means An active vibration noise control device characterized by adjusting the frequency. In the active vibration noise control device according to any one of claims 1 to 4,
The control unit is configured to set the feature amount or the frequency characteristic among a plurality of parameters stored in advance for at least one feature amount of the peak frequency and attenuation coefficient of the sensor output or for each frequency characteristic of the sensor output. An active vibration noise control apparatus characterized by adjusting an output from the wave applying means by calculating a linear sum of close parameters. In the active vibration noise control device according to any one of claims 1 to 4,
The control means redesigns a parameter using the frequency characteristic of the output signal acquired from the output signal of the sensor, and adjusts the output by the wave applying means using the redesigned parameter. Active vibration noise control device. In the active vibration noise control device according to any one of claims 1 to 8,
The control unit uses at least one of a peak frequency and an attenuation coefficient of the output signal of the sensor as a feature amount, and adjusts an output by the wave applying unit when the feature amount is different from a predetermined value held in advance. An active vibration noise control device characterized by the above. In the active vibration noise control device according to any one of claims 1 to 9,
The control means holds the frequency characteristic of the output signal of the sensor in advance, and obtains a correlation coefficient between the frequency characteristic and the frequency characteristic of the output signal newly acquired from the sensor, and this correlation An active vibration noise control device, wherein the output by the wave applying means is adjusted when the number becomes a predetermined value or less. In the active vibration noise control device according to any one of claims 1 to 10,
The control means uses the reduction amount of the internal noise of the structure by the noise reduction control as a feature amount, and adjusts the output by the wave applying means when the feature amount is reduced by a predetermined amount. Noise control device. In the active vibration noise control device according to any one of claims 1 to 11,
The control means uses a numerical value obtained based on one of a peak frequency of internal noise of the structure estimated based on an output signal of the sensor and an attenuation coefficient as a feature amount, and the feature amount is An active vibration and noise control apparatus, wherein an output from the wave applying means is adjusted when the predetermined value is different from a predetermined value. The active vibration noise control device according to any one of claims 1 to 12,
The control means obtains a correlation between a frequency characteristic of estimated noise generated inside the structure held in advance and a frequency characteristic of an output signal newly acquired from the sensor, and the correlation coefficient is An active vibration noise control apparatus, wherein an output from the wave applying means is adjusted when a predetermined value or less is reached. In the active vibration noise control device according to any one of claims 1 to 13,
The control means adjusts the output by the wave applying means when the internal noise of the structure estimated based on the output signal of the sensor is different from a preset maximum frequency. Noise control device. In the active vibration noise control device according to any one of claims 1 to 14,
The active vibration noise control apparatus characterized in that the structure is a moving body and estimates a change in frequency characteristics of an output signal of the sensor based on a change in speed of the moving body.

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