JP2007219262A - Active vibrating noise controlling apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an active vibrating noise controlling apparatus, capable of reducing only noise caused by vibration of a casing which is a control object, without reducing in-vehicle music and voice of an attendant which is not a control object. <P>SOLUTION: The active vibrating noise controlling apparatus comprises: a case 5 in which vibration propagates from outside to inside as noise; a sensor 7 for detecting the vibration of the casing 5; an actuator 8 for generating control vibration on the casing 5; a signal arithmetic means 31 for generating a control instructing signal to the actuator 8 so that the noise in the case may be reduced; and a noise estimating means 32 for estimating the noise inside the casing by using the output signal of the sensor 7 and the control instruction signal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an active vibration noise control device that reduces vibration or noise by superimposing control vibration on vibration or noise that enters the casing from the outside.

A noise control device that performs feedback control for the purpose of reducing vehicle interior noise is disclosed in Patent Document 1. Here, an object is to reduce road noise in a frequency band of 100 Hz or less using a microphone. The low frequency road noise is assumed to be caused by the acoustic mode of the vehicle interior sound field, and a feedback control is performed by installing a microphone on the belly of the acoustic mode.
JP 2000-322066 A

  However, in the above-described noise control device, vehicle interior noise is measured using a microphone, and therefore interior music that is not required to be controlled, passenger voices, and the like are also used as reference signals together with road noise, and are reduced by feedback control. There was a problem that it was.

  Further, since a large number of microphones are arranged in the vehicle interior, there is a problem that the cost of the microphone itself and the cost and weight of the harness increase.

  Furthermore, since the harness is realized by running around the vehicle interior, there is a problem that the harness length becomes long and the reliability of the system deteriorates.

  A feature of the present invention is that a housing that transmits vibration from outside to inside as noise, a sensor that detects vibration of the housing, an actuator that generates control vibration in the housing, and noise in the housing are reduced. The active vibration noise control device includes a signal calculation unit that generates a control command signal to the actuator, and a noise estimation unit that estimates the noise in the housing using the output signal of the sensor and the control command signal.

  According to the active vibration noise control device according to the present invention, by estimating the noise in the housing using the output signal of the sensor and the control command signal, it is possible to reduce vehicle interior music and occupant voice that are not controlled. Only the noise caused by the vibration of the casing to be controlled can be reduced.

  Embodiments of the present invention will be described below with reference to the drawings. In the description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

(First embodiment)
With reference to FIG. 1, the overall configuration of an active vibration noise control apparatus according to a first embodiment of the present invention will be described. An active vibration noise control device (AVC: Active Vibration Controller) according to the first embodiment detects vibrations of a casing (vehicle body 5) that transmits vibration from outside to inside as noise and a casing that is transmitted from the outside. A sensor (acceleration sensor 7), an actuator 8 that generates control vibration in the housing, and a signal that generates a control command signal to the actuator 8 so as to reduce noise transmitted to the inside of the housing (in-housing noise). Calculation means (controller 31) and noise estimation means (noise estimation unit 32) for estimating the noise in the housing using the output signal of the acceleration sensor 7 and the control command signal to the actuator 8 are provided.

  Any housing may be used as long as vibration is generated by a force applied from the outside and the vibration can be transmitted to the inside as noise. This includes, for example, human moving means such as airplanes, trains, cars, and elevators. In particular, since an automobile travels with a tire on a road surface with severe irregularities, control of vibration transmitted from the tire is an important technical issue. Therefore, in the embodiment, a case where the active vibration noise control device according to the present invention is applied to an automobile will be described as an example. That is, here, a vehicle body will be described as an example of a housing.

  The acceleration sensor 7 is a sensor having a function of measuring acceleration applied to itself, and by detecting the acceleration by fixing the acceleration sensor 7 on the vehicle body, the vibration of the vehicle body is detected from the change in the measured acceleration. Can do. In addition to the acceleration sensor 7, the sensor for detecting the vibration of the casing transmitted from the outside may be a sensor that directly detects the vibration from a change in the position (coordinates) at which the sensor is fixed, or transmitted from the tire. As long as vibration is detected, it may be a sensor that detects vibration of a tire or an axle to which the tire is connected. In the example of FIG. 1, the acceleration sensor 7 is fixed to the lower surface of the floor panel 6 that is closer to the tire 4 than the hood or roof panel in the vehicle body 5.

  The actuator 8 is fixed under the floor panel 6 in the vehicle body 5, and generates distortion in the floor panel 6 by receiving distortion in response to an electrical signal (control command signal). Thereby, the control vibration is generated in the vehicle body 5 to cancel the vibration or noise caused by the disturbance. As the actuator 8, a piezo-electric actuator utilizing a piezo effect (piezoelectric effect) that generates a strain proportional to the electric field when an electric field is applied to the crystal can be used. The actuator 8 is distorted by applying an electric field to both surfaces of the actuator 8.

  The controller 31 and the noise estimation unit 32 are included in the controller unit 30. The controller unit 30 calculates a control command value for reducing vehicle interior noise based on the signal obtained by the acceleration sensor 7. The controller unit 30 includes a signal amplification amplifier 33 a that amplifies the signal obtained by the acceleration sensor 7, and a noise estimation unit 32 that estimates vehicle interior noise based on the output signal of the acceleration sensor 7 and the control command signal to the actuator 8. And a controller 31 that calculates a control command value for the actuator 8 that reduces vehicle interior noise based on the estimated noise estimated by the noise estimation unit 32.

  Typical causes of vehicle interior noise are noise caused by the vibration of the engine 10, noise called road noise caused by road surface unevenness entering from tires during driving, and airflow during driving Wind noise, etc. In addition, road noise entering from the tire is transmitted to the vehicle interior via vibration of the tire and the floor panel. That is, the vibration of the floor panel 6 is transmitted as noise to the inside of the vehicle body 5 (vehicle interior). In the present embodiment, the noise estimation unit 32 mainly estimates the vehicle interior noise caused by the vibration of the floor panel 6. Therefore, the acceleration sensor 7 is disposed under the floor panel 6 to estimate the vehicle interior noise. To do. Therefore, control is performed mainly on road noise caused by floor panel vibration among the vehicle interior noise in the above example.

  As shown in FIG. 2, the four tires 4 of the vehicle vibrate due to the road surface unevenness, and the main component of road noise entering the vehicle body from the tire 4 is first attached to the axle and suspension. From a point, it enters a highly rigid beam-like member called a member. Thereafter, the transmission is transmitted to a plate-like member called a floor panel 6 surrounded by the members and having relatively low rigidity, and the floor panel 6 vibrates. Furthermore, the air vibration in the vehicle interior 9 is caused by the membrane vibration of the floor panel 6, causing a resonance phenomenon in the vehicle interior 9. For this reason, noise as road noise is heard in the passenger compartment 9. Although noise is generated when the roof panel and the window glass vibrate in addition to the floor panel 6, most of the road noise that mainly enters from the suspension mounting portion is caused by the vibration of the floor panel 6. I know it. The acceleration sensor 7 is disposed on the road noise intrusion path connecting the tire 4 and the vehicle interior 9.

  In addition to a road noise approach path from a general tire 4, there is a control vibration transmission path by an actuator 8 attached to the floor panel 6. The control vibration generated by the actuator 8 vibrates the floor panel 6 in the same way as road noise, and air vibration in the vehicle interior 9 occurs due to membrane vibration of the floor panel 6, and becomes control noise to the vehicle interior 9. On the other hand, vibration generated from the actuator 8 also propagates to the acceleration sensor 7. Therefore, the vibration of the floor panel 6 measured by the acceleration sensor 7 has the same position among the vibration that enters the vehicle body from the tire 4 and the component that passes through the mounting position of the acceleration sensor 7 and the control vibration that the piezo actuator 8 generates. It becomes a vibration that is superposed on the passing component.

  A range 9 in FIG. 2 indicates a spherical region including an occupant ear position as an example of a vehicle interior space. The noise in this space becomes vehicle interior noise in which noise input from the tire 4 to the vehicle body and control vibration generated by the actuator 8 are superimposed. The controller 31 supplies a control command signal for reducing noise in the vehicle interior region 9 to the actuator 8 to generate control vibration. Noise in the vehicle interior region 9 is reduced by superimposing the vibration of the floor panel 6 caused by the road surface unevenness and the control vibration generated by the actuator 8 so as to cancel each other.

  The controller 31 in FIG. 1 has a fixed coefficient having a function of calculating a control command signal that reduces the noise in the vehicle interior space 9 by using the sound pressure (vehicle interior noise) estimated by the noise estimation unit 32 as an input. FIR or IIR filter. For example, the controller 31 may be designed according to the following procedure.

First, modeling of “transfer characteristics from a control command signal to the actuator 8 to noise in the vehicle interior space 9” is performed. The modeling procedure is as follows. First, the actuator 8 and the microphone are installed in the floor panel 6 and the vehicle interior space 9, respectively. An M-sequence signal generated in advance is input to the actuator 8, and the input signal and the microphone signal are measured. By using the system identification method described in, for example, Lennart Ljung, “System Identification. Second edition. Thorough for the user”, Parent Hall PTR, 1999, for example, a state space model.
x (n + 1) = Ax (n) + Bu (n)
y (n) = Cx (n) + Du (n)
Is modeled in the form Here, x (t) is a model state variable, u (t) is an input signal to the piezoelectric actuator, y (t) is a sound pressure in the vehicle interior space 9, and matrices A, B, C, and D are Each is a model parameter. N represents the sample time.

Next, a control system design method will be described with reference to the block diagram shown in FIG. Here, the controller 34 receives the signal B and outputs a control command signal to the actuator 8. The control command signal is input to the transfer function model 35. The transfer function model 35 is a model indicating “transfer characteristics from the control command signal of the actuator 8 to the noise in the vehicle interior space 9” modeled in the above procedure. The signal output from the transfer function model 35 and the signal A (disturbance) are overlapped to form a signal B (vehicle interior noise). The controller 34 may be designed so that the transfer characteristic from the signal A to the signal B in FIG. 3 becomes small in a desired frequency band. As a design method, for example, PID control, H2 control, H∞ control, or the like can be used. Also,
Hosoe, Araki, “Control System Design, H∞ Control and its Applications”, Asakura Shoten, 1994
Suda, “PID Control”, Asakura Shoten, 1992
By using the design method described in the above, it is possible to design the I-order dynamic controller Ki, i = 1,.

  As shown in FIG. 4, the noise estimation unit 32 receives the floor panel vibration (output signal) obtained by the acceleration sensor 7 and the control command signal to the actuator 8. The noise estimation unit 32 includes a first transmission model 14 representing transmission characteristics from vibration at a position where the acceleration sensor 7 is attached to noise in the vehicle interior space 9, and a control command signal to the actuator 8 in the vehicle interior space 9. The second transfer model 15 representing the transfer characteristic up to noise and the third transfer model 16 representing the transfer characteristic from the control command signal to the actuator 8 to the vibration of the acceleration sensor 7 are stored as data. The first to third transmission models 14, 15, and 16 are mathematical models of the transmission paths 1, 2, and 3 in FIG. The first to third transfer models 14, 15, and 16 can be obtained by following the above modeling procedure.

  More specifically, the first transmission model 14 represents a transmission characteristic when the floor panel vibration at the position where the acceleration sensor 7 is attached is transmitted to the vehicle interior space 9. The second transfer model 15 represents a transfer characteristic when an input signal to the actuator 8 is input to the actuator 8 and a control vibration generated by the actuator is transmitted to the vehicle interior space 9. The third transmission model 16 represents a transmission characteristic when an input signal to the actuator 8 is input to the actuator 8 and a control vibration generated by the actuator is transmitted to a position where the acceleration sensor 7 is installed.

  Next, an example of an algorithm for estimating the vehicle interior noise by the noise estimation unit 32 will be described.

  First, in the first algorithm, the noise estimation unit 32 inputs the output signal of the acceleration sensor 7 “as is” to the first transmission model 14 and inputs the control command signal to the second transmission model 15. Then, the sum of output values obtained from both models 14 and 15 is output as vehicle interior noise (estimated sound pressure: SPL).

  In the second algorithm, the noise estimation unit 32 subtracts the vibration component generated by the actuator 8 from the output signal of the acceleration sensor 7 and inputs this to the first transmission model 14. Then, the sum of the output obtained from the first transmission model 14 and the output obtained by inputting the control command signal to the second transmission model 15 is output as vehicle interior noise. In this way, by subtracting the vibration component generated by the actuator 8 from the output signal of the acceleration sensor 7, the control vibration by the actuator 8 is removed from the output value of the acceleration sensor 7, and only road noise due to road surface unevenness is obtained. And the measurement accuracy of road noise (disturbance) is improved.

  The second algorithm will be described specifically. As shown in FIG. 4, the noise estimation unit 32 uses a signal obtained by subtracting the output of the third transfer model 16 from the output signal of the acceleration sensor 7 as the first transfer model 14. The sum of the output obtained by inputting to and the output obtained by inputting the control command signal to the second transfer model 15 is output as vehicle interior noise.

  Details of the noise estimation procedure (second algorithm) by the noise estimation unit 32 shown in FIG. 4 will be described with reference to the flowchart of FIG.

  (A) First, the output signal of the acceleration sensor 7 is input to the noise estimation unit 32 in step S101. This is signal C.

  (B) Proceeding to step S102, the control command signal for the actuator 8 is input to the noise estimation unit 32. This is signal D.

  (C) Proceeding to step S103, the signal D is multiplied by the third transfer model 16. This is signal E.

  (D) Proceeding to step S104, the signal E is subtracted from the signal C. This is signal F. In step S105, the signal F is multiplied by the first transfer model 14. This is a signal G.

  (E) Proceeding to step S106, the signal D is multiplied by the second transfer model 15. This is signal H.

  (F) Proceed to step S107, and the signal G and the signal H are added. This is signal J. Finally, in step S108, the signal J is output as the estimated sound pressure at the vehicle interior space position 9.

  Next, the effect by estimating vehicle interior noise using the noise estimation part 32 mentioned above is demonstrated. FIG. 6 is a diagram comparing the sound pressure at the driver's right ear position actually measured with the sound pressure at the same position estimated using the noise estimation device. The driver's seat right ear position is an example of the vehicle interior position 9. Here, the solid line 42 is the noise (actually measured sound pressure) actually measured by the microphone at the vehicle interior position 9, and the dotted line 43 is the estimated sound pressure by the noise estimating unit 32. As shown in FIG. 6, the estimated sound pressure has a value substantially equal to the actually measured sound pressure. Therefore, it can be seen that the vehicle interior noise can be accurately estimated by the noise estimation unit 32 without using a microphone.

FIG. 7 shows a change in coherence between the actually measured sound pressure and the estimated sound pressure due to the presence or absence of the third transfer model 16 of FIG. The solid line 46 shows the case where the third transmission model 16 is present in FIG. 4 (second algorithm), that is, the first transmission signal obtained by subtracting the vibration component generated by the actuator 8 from the output signal of the acceleration sensor 7. The case where it inputs to the model 14 is shown. A dotted line 47 indicates a case where there is no third transmission model 16 (first algorithm), that is, a case where the output signal of the acceleration sensor 7 is input to the first transmission model as it is. FIG. 7 shows a result of calculating a coherence function between the estimated sound pressure estimated by the noise estimation unit 32 and the actually measured sound pressure measured by the microphone. Here, the coherence function is a measure representing the correlation between two signals and representing the estimation accuracy, and the coherence function between the signals x (t) and y (t) is defined by Equation 2.

Here, C _xy is the coherence between the signal x (t) and the signal y (t), S _xy is the cross spectral density between the signal x (t) and the signal y (t), S _x , S _y Represents the spectral densities of the signal x (t) and the signal y (t), respectively. The value of the coherence function is 1 when the actually measured sound pressure and the estimated sound pressure completely match, and the value of the coherence function is 0 when the two signals are uncorrelated.

  As can be seen from FIG. 7, the coherence function is higher when the third transfer model 16 is inserted than when the third transfer model 16 is not inserted. Therefore, it can be seen that by inserting the third transmission model 16, more accurate sound pressure estimation is realized.

  As described above, according to the first embodiment of the present invention, the following operational effects can be obtained.

  Since the microphone is not installed in the vehicle interior 9 by providing the noise estimation unit 32, it is possible to perform control to reduce only vehicle interior noise caused by vibration entering from outside the vehicle without reducing the voice and music of the occupant. I can do it. In addition, the control effect is improved because the distance between the sensor and the actuator is short and the dead time is short as compared with the case of controlling using a microphone.

  In addition, by providing the first and second transfer models 14 and 15, estimation can be performed using the first and second transfer models 14 and 15, and a transient response is avoided and the estimation accuracy is good. Become. As a result, the effect of noise reduction control is enhanced.

  Specifically, by making the sum of the output values obtained by inputting to the first and second transfer models 14 and 15 into the vehicle interior noise, a transient response is avoided and the estimation accuracy is improved.

  In addition to the first and second transmission models 14 and 15, the third transmission model 16 is further provided, so that even when the control command signal of the actuator 8 becomes large, the output signal of the acceleration sensor 7 from outside the vehicle. Since the entering vibration component (disturbance) can be accurately measured, the estimation accuracy of the vehicle interior sound pressure is increased. Further, the degree of freedom of arrangement of the acceleration sensor 7 and the actuator 8 is increased. As a result, the effect of noise reduction control is enhanced.

  Since only the third transmission model 16 from the actuator 8 to the vibration is used, the vibration estimation unit 32 that is simpler and more accurate can be formed. As a result, the effect of noise reduction control is enhanced.

  By taking a vehicle body as an example of the case and disposing the acceleration sensor and the actuator on the floor panel of the vehicle body, it is possible to remove vehicle interior noise.

(Second Embodiment)
In the second embodiment, an example in which the present invention is applied to a feedforward active vibration control device will be described.

  First, a feedforward active vibration control apparatus using a generally known adaptive filter will be described with reference to FIGS. 8 to 10, and then the present embodiment will be described with reference to FIGS. 11 and 12. The feedforward active vibration control apparatus will be described.

  As shown in FIG. 8, a conventionally known feedforward active vibration control device using an adaptive filter includes an acceleration sensor 39 that measures the influence of road surface unevenness input to the vehicle body, and a vehicle interior space 9. Control the operation of the actuator 8 by calculating a control command signal to the actuator 8 in order to reduce the noise in the predetermined space 9 in the vehicle interior 40 and the microphone 8 that detects noise, the actuator 8 disposed on the floor panel. And a controller unit 36.

  The controller unit 36 includes an amplifier 33a that amplifies the signal from the microphone 54, an adaptive law calculation unit 37 that controls the adaptive filter 38 based on the signal from the microphone 54, and an amplifier 33c that amplifies the output signal of the acceleration sensor 39. And an amplifier 33b for amplifying the output of the adaptive filter 38.

  FIG. 9 is a block diagram of the entire system of FIG. The controller unit 36 is realized by a normal computer system or an electronic circuit. The first vibration propagation path 41 represents a transfer function from the output signal of the acceleration sensor 39 to the noise in the vehicle interior space 9, and the second vibration propagation path 42 is transmitted from the control command signal to the actuator 8 in the vehicle interior space 9. Represents the transfer function up to noise.

Hereinafter, a method of calculating a control command signal to the actuator 8 in the system of FIG. 8 will be described with reference to FIG. X (n) is a signal obtained by the acceleration sensor 39, y (n) is a noise generated in the vehicle interior space 9 by a disturbance input from the road surface to the vehicle body, u (n) is a control command signal to the piezoelectric actuator 8. The error signal obtained by the microphone 54 is set as e (n). Here, n represents the sample time. Further, the models of the adaptive filter 38, the first vibration propagation path 41, and the second vibration propagation path 42 are represented by Equation 3, Equation 4, and Equation 5, respectively.

Here, z ^-i represents an operator of Z conversion. The reason why w _i depends on the sampling time n is that a variable coefficient filter is used. The output of the adaptive filter 38 is calculated as an input signal to the actuator 8. At this time, the signals y (n) and u (n) are calculated as Equation 6 and Equation 7, respectively.

  U (n) calculated based on the above formula is input to the actuator 8.

On the other hand, the adaptive law calculation unit 37 updates the filter coefficient w _i (n) by the following calculation. First, the evaluation function J is defined as Equation 8.

In a generally known LMS (Least Mean Square) algorithm, the applied filter is updated so that the evaluation function J is minimized with respect to w _i (n). The update rule for w _i (n) is given by Equation 9. Here, Ke and Ky are design parameters.

Also, r (ni) is defined by Equation 10.

  The above update calculation is performed by the adaptive law calculation unit 37.

  Next, the calculation procedure performed by the adaptive filter 38 will be described with reference to the flowchart of FIG.

  (Ii) First, in step S201, output signals of the acceleration sensor 39 and the microphone 40 are acquired every sampling time n. Proceeding to step S202, a command signal u (n) to the actuator is obtained by calculating the output signal x (n) of the acceleration sensor 39 using the formula (7).

(B) Proceeding to step S203, using the output signal e (n) of the microphone and the output signal x (n) of the acceleration sensor 39, the updated filter coefficient w _i (n) is calculated according to Equations 9 and 10. calculate. Proceeding to step S204, the filter coefficient w _i (n) calculated at step S203 is updated.

  In step S205, the control command signal u (n) to the actuator calculated in step S202 is output. Feed forward control is performed by performing steps S201 to S205 every sample time n, and noise in the vehicle interior space 9 can be reduced.

  Next, the feedforward active vibration noise control apparatus according to this embodiment will be described.

  As shown in FIG. 11, in the feedforward type active vibration control apparatus according to the second embodiment, the second acceleration sensor 7 is a floor instead of the microphone arranged in the vehicle interior space 9 as compared with FIG. Affixed to a predetermined location on the panel. In addition, a noise estimation unit 32 is disposed between the amplifier 33 a and the adaptive law calculation unit 37, and an output signal from the adaptive filter 38 is input to the noise estimation unit 32. That is, the signal obtained from the second acceleration sensor 7 through the amplifier 33 a and the control command signal to the actuator 8 are input to the noise estimation unit 32. Here, the noise estimation unit 32 may use a device similar to the example shown in FIG. The output signal of the noise estimation unit 32 is an estimated sound pressure in the vehicle interior space 9. Therefore, the adaptive law calculating unit 37 receives the estimated sound pressure by the noise estimating unit 32 instead of the actually measured sound pressure by the microphone of FIG. The adaptive filter 38 calculates a control command signal for reducing noise in the vehicle interior space 9 based on the disturbance signal obtained from the acceleration sensor 39.

  With reference to FIG. 12, the calculation procedure of the controller unit 36 of FIG. 11 will be described.

  (A) First, in step S301, the output signal of the first acceleration sensor 39 used for measuring vibration transmitted from the outside of the vehicle via the tire to the vehicle body, and the second acceleration sensor used for estimating vehicle interior noise. 7 output signals are obtained.

  (B) Proceeding to step S302, the control command signal u (n) to the actuator 8 is obtained by performing the calculation of Expression 7 on the output signal x (n) of the first acceleration sensor 39. Proceeding to step S303, using the output signal of the second acceleration sensor 7 and the control command signal u (n) to the actuator 8 to perform noise estimation calculation by the algorithm shown in FIG. Calculate the estimated sound pressure (estimated noise).

(C) Proceeding to step S304, using the estimated noise calculated in step S303 and the output signal x (n) of the first acceleration sensor 39, the updated filter coefficients according to the mathematical expressions of Equations 9 and 10 Calculate w _i (n). Proceeding to step S305, the filter coefficient w _i (n) calculated at step S304 is updated.

  (D) Proceeding to step S306, the control command signal u (n) to the actuator 8 calculated at step S202 is output. Feed forward control is performed by performing steps S301 to S306 every sample time n, and noise in the vehicle interior space 9 is reduced.

  Thus, by estimating the noise in the vehicle interior space 9 by the noise estimation unit 32, it is not necessary to equip a microphone as compared with the conventional type shown in FIG. 8, and a feedforward type active vibration control device is realized. be able to. Therefore, as in the first embodiment, since no microphone is installed in the vehicle interior space 9, control is performed to reduce only vehicle interior noise caused by vibrations entering from outside the vehicle without reducing the voice and music of the occupant. Can be done. In addition, the control effect is improved because the distance between the acceleration sensor and the actuator is short and the dead time is short as compared with the case where control is performed using a microphone.

  In order to simplify the description, the number of acceleration sensors is one in the first embodiment, two in the second embodiment, and a system with one actuator is described as an example. The same discussion can be made for a system including a plurality of sensors and actuators, and the present invention can be applied. That is, the number of acceleration sensors and actuators does not narrow the scope of the claims of the present invention.

  Actually, when performing noise reduction control in t vehicle interior spaces using r acceleration sensors and s actuators, the noise estimation unit 32 in FIGS. 1 and 11 is changed to the configuration shown in FIG. That's fine. In FIG. 13, symbols r, s, and t beside a signal line indicate the number of channels of the signal line. The first transfer model 14 is a transfer function matrix of t rows and r columns from the output signal of the acceleration sensor to the noise in the vehicle interior space 9, and the second transfer model 15 is a vehicle interior space 9 from the control command signal to the actuator. The third transfer model 16 is an r row and s column transfer function matrix from a control command signal to the actuator to a vibration at the mounting position of the acceleration sensor. As described above, since there are a plurality of acceleration sensors and actuators, the signal lines for transmitting the output signal and the control command signal are made into a plurality of channels, and the first to third transmissions are held in advance in the noise estimation unit 32. The models 14 to 16 are made into a matrix form. Thus, the first and second embodiments can be easily expanded even in the case of a plurality of sensors and actuators.

(Third embodiment)
Before explaining the active vibration noise control apparatus according to the third embodiment, first, the active vibration noise control apparatus is mounted with reference to FIG. 14 (a), FIG. 14 (b) and FIG. The structure of the vehicle will be described.

  As shown in FIGS. 14A and 14B, the floor panel 6 of the vehicle body 5 to which the actuator is fixed can be divided into three main parts. Specifically, the floor panel 6 includes a flat cabin floor 17 positioned under a seat on which an occupant sits, a tank panel 18 to which a fuel tank is fixed, and a spare tire panel positioned under a spare tire and a trunk. 19. The cabin floor 17 is located between the engine room and the tank panel 18. The spare tire panel 19 is located between the tank panel 18 and the rear end of the vehicle body 5.

As shown in FIG. 15, on the floor panel 6 in FIG. 14B, there are vertical members 20 a to 20 d extending in the vertical direction toward the traveling direction of the vehicle, and horizontal members 21 a to 21 d extending in the horizontal direction. Has been placed. Since the floor panel 6 is formed in a thin flat plate shape to reduce the weight of the vehicle body, sufficient rigidity cannot be obtained with the floor panel 6 alone. The bar-shaped vertical members 20a to 20d and the horizontal members 21a to 21d having higher rigidity than the floor panel 6 are fixed on the floor panel 6 to increase the rigidity of the floor panel 6. The vertical members 20 a to 20 d and the horizontal members 21 a to 21 d are formed thicker than the floor panel 6. The vertical members 20a to 20d and the horizontal members 21a to 21d may be fixed to only one surface (front surface or back surface) side of the floor panel 6 or may be fixed to both surfaces (front and back surfaces). Next, an active vibration noise control apparatus according to the third embodiment of the present invention will be described. In general, vibration and noise propagating from the road surface to the vehicle body via the tire have properties as waves. Therefore, it takes a certain delay time for the vibration of the floor panel to be transmitted to the noise in the passenger compartment. . That is, vibration and noise are not transmitted instantaneously from the floor panel to the passenger's ears, but are transmitted with a certain delay time. The noise estimation performance of the noise estimation unit 32 is greatly influenced by this delay time. The noise estimation unit 32 estimates the noise in the vehicle interior space from the vibration at the mounting position of the acceleration sensor using the first transmission model, and uses the second transmission model to calculate the vehicle interior from the control command signal to the actuator. Estimates the noise in the space. Therefore, it is desirable that the delay time from the floor panel to the vehicle interior space is included in the noise estimation unit 32. In the third embodiment, an apparatus and method for estimating vehicle interior noise in consideration of vibration and noise delay times transmitted as waves from the floor panel to the vehicle interior space will be described.

  As shown in FIG. 16, a feedback type active vibration noise control device (NRC: Noise Reduction) that arranges a microphone 40 in a vehicle interior space, measures vehicle interior noise, and controls a control command signal to an actuator on the floor panel. Control) is generally known. This device uses the actuator 8 to generate control vibrations on the floor panel of the vehicle body so that noise (sound pressure level SPL: Sound Pressure Level [dB]) at one or more measurement points in the passenger compartment is reduced. The purpose is to do. One or more actuators 8 are installed at predetermined positions on the floor panel to generate a control vibration on the floor panel. Then, one or two or more microphones 40 are installed at predetermined positions in the vehicle interior, and vehicle interior noise is measured. The sound pressure level SPL measured by the microphone 40 is input to the feedback type controller 43. As the controller 43, for example, general H∞ control can be used. The vibration of the floor panel due to the disturbance and the control vibration by the actuator 8 are transmitted as vehicle interior noise over a predetermined delay time, and are measured by the microphone 40 as the sound pressure level. Therefore, the control system shown in FIG. 16 has a configuration including all physically existing delay times. Here, all delay times include the first delay time from disturbance (in this case, vibration and noise entering the vehicle body via the tire due to road surface irregularities) to the vehicle interior space, and from the actuator to the vehicle. And a second delay time to the indoor space.

  On the other hand, FIG. 17 shows an active vibration noise control apparatus that estimates vehicle interior noise using a transfer model from vehicle body vibration to vehicle interior noise without directly measuring room noise with a microphone. In the apparatus of FIG. 17, the noise estimation unit 32 is provided as a virtual microphone. If there is no error between the transfer function provided in the noise estimation unit 32 and the actual transfer system, the systems in FIG. 16 and FIG. 17 match exactly, and the microphone 40 can be replaced with the noise estimation unit 32.

As the controller 31, for example, general H∞ control can be used. An open-loop transfer model between the actuator control command signal V and the vehicle interior sound pressure SPL can be obtained in the form of a general transfer function. Further, as described above, the apparatus shown in FIGS. 16 and 17 can be easily applied to a system including a plurality of control command signals V and a plurality of vehicle interior sound pressures SPL. A system consisting of an open loop is expressed by Equation 11. Here, s is a variable in Laplace transform.

The controller 31 can perform the calculation using a loop shaping design procedure. This calculation method is described in D.A. McFarlane and K.M. Golver, IEEE Transactions on Automatic Control. vol. 37, no. 6, June 1992, pp. 759-769, “A Loop Shaping Design Procedure Using H∞ Synthesis”. Here, _C∞ is obtained by the calculation formula shown in Equation 12.

Here, Gs is a transfer function of the system weighted by W ₁ and W ₂ and is called a shaping function.

The controller C shown in FIG. 16 that satisfies such a conditional expression is expressed by Equation 14.

Here, W ₁ and W ₂ are usually transfer functions of a filter that can select a frequency band of vibration and noise to be controlled. [Ms] and Ns are standardized Gs coprime factors as shown in Equation 15. The parameter ε is called a stable allowable range, and 0.2 to 0.3 is usually appropriate.

  Next, the noise estimation unit 32 in FIG. 17 will be described. The noise estimation unit E is replaced with the microphone 40 in the transmission of the vehicle interior noise SPL. Since the noise estimation unit E actually estimates the in-cabin noise [SPL], it is desirable that the transmission model used by the noise estimation unit E is as accurate as possible. Hereinafter, the estimated in-cabin noise (sound pressure) is denoted as [SPL], and the cabin noise actually measured by the microphone is denoted as SPL.

  As shown in FIG. 18, the controller unit 30 according to the third embodiment includes a noise estimation unit 32 and a controller 31. The plant 5 shows a vehicle body as an example of a housing that transmits vibration and noise from disturbance d and actuator control vibration to vehicle interior noise SPLi. The noise estimation unit 32 receives the output signal 7 from the acceleration sensor and the control command signal transmitted from the controller 31 to the actuator 8 in the plant 5 as the disturbance d, and estimates the vehicle interior noise [SPL] i. Based on the vehicle interior noise [SPL] i, the controller 31 controls the control command signal to the actuator 8 so that the vehicle interior noise SPLi output from the plant is reduced.

  As shown in FIG. 19, the noise estimation unit 32 in FIG. 18 includes a first transfer model Gd representing transfer characteristics from a position where the acceleration sensor 7 in FIG. 17 is attached to a point for estimating the vehicle interior noise SPL, A second transfer model Ga indicating transfer characteristics from the control command signal to the actuator 8 to the vehicle interior noise SPL is provided as data. The noise estimation unit E adds the output value obtained by inputting the output signal of the acceleration sensor 7 to the first transfer model Gd and the output value obtained by inputting the control command signal to the second transfer model Ga. Is output as vehicle interior noise [SPL] i.

  Here, the second transmission model Ga may indicate a transmission characteristic from the floor panel position where the actuator 8 is disposed to a point where the vehicle interior noise is estimated.

  The first transmission model Gd and the second transmission model Ga are obtained by specifying the plant 5 to which the vibration is transmitted, and preferably include all the physical characteristics of the actual plant 5. Therefore, it is desirable that the first and second transmission models include time (delay time) necessary for transmitting noise and vibration as waves from the floor panel to the vehicle interior noise.

  As shown in FIG. 19, the noise estimation unit 32a receives a control command signal V to the actuator and a signal α indicating disturbance. As a result, the control command signal V corresponds to the vibration of the floor panel 6 at the position where the actuator 8 is installed. The signal α indicating the disturbance corresponds to the vibration of the floor panel measured by the acceleration sensor 7.

  When the noise estimation unit 32a estimates the vehicle interior noise [SPL] with sufficient accuracy, the active vibration control device shown in FIG. 17 is an active vibration control device of the type that actually measures the vehicle interior noise SPL with the microphone shown in FIG. Match exactly. The advantage of the system of FIG. 17 is that a microphone disposed in the passenger compartment is not required, and there is no risk that the radio noise, the occupant's voice, the wind noise, etc. will be drowned out by the control vibration as well as the road noise.

  However, since the noise estimation unit 32a includes the delay time that the actual plant 5 has, high control efficiency of the controller cannot be expected. Therefore, in the third embodiment, a new structure of the noise estimation unit E is proposed in order to realize better control efficiency, that is, noise removal efficiency. That is, better control efficiency is realized by compensating the delay time and estimating the vehicle interior noise SPL based on a delay time shorter than the delay time actually generated in the plant 5.

  A plant that does not include a time delay has a simpler structure than a plant that includes a delay time, and has high control efficiency and a large control gain. On the other hand, in the case of a plant including a delay time, noise control is difficult and the control gain cannot be increased, so that the control efficiency is usually low. Therefore, a different delay time of the plant is calculated and evaluated, and this is removed from the noise estimation unit E. The new noise estimation unit [E] obtained in this way can predict the estimated vehicle interior noise SPL rather than simply estimating the vehicle interior noise SPL.

  FIG. 20 shows a configuration of the noise estimation unit 32b in consideration of the delay time. The information α regarding the disturbance is first input to the first transmission model 14 b and then input to the delay time model 44. On the other hand, the control command signal V to the actuator is input to the second transmission model 15 b and then input to the delay time model 45.

A method for shortening (compensating) the delay times Ta and Td using the delay time compensation τ will be described. The noise estimation unit [E] includes Ga (s) and Gd (s) as shown in Equation 16.

  In Equation 16, the first transfer model [G] a (s) and the second transfer model [G] d (s) are obtained by removing the delay time terms of Ga (s) and Gd (s), respectively. It corresponds to. FIG. 21 shows a system including one actuator 8, one disturbance (acceleration sensor 7), and one vehicle interior noise SPL.

  Since the noise estimation unit [E] uses Ga (s) and Gd (s) shown in Equation 16, the delay times Ta and Td can be easily shortened using the delay time compensation τ without any hardware change. can do. This feature is an advantage of using a signal output from the noise estimation unit instead of the microphone. When the delay time Td is equal to or longer than the delay time Ta, the delay time compensation τ is equal to the delay time Ta. In this case, the actuator behaves as if there is no time delay. Here, [E] indicates a noise estimation unit that compensates for the delay time.

The controller unit C is calculated using the noise estimation unit [E]. The calculation of the controller unit C is as described above, but the equation 17 is used instead of the equation 11.

  FIG. 22 shows a configuration of the noise estimation unit 32c that compensates for the delay time. A signal related to the disturbance is first input to the first transfer model 14b, and then input to the delay time model 44b compensated for the delay time by τ. On the other hand, the control command signal V to the actuator is input to the second transmission model 15b and then input to the delay time model 45b compensated for the delay time by τ. Vehicle interior noise [SPL] can be estimated by superimposing the output signals of the delay time models 44b and 45b.

  FIG. 23 shows a system composed of one actuator 8, one disturbance (acceleration sensor 7) and one vehicle interior noise SPL, and only a delay time model compensated for the delay time is shown on the transmission path.

  There are three methods for calculating or estimating the delay times Ta and Td compensated for the delay time.

First, the delay time can be estimated by calculating the distance traveled. The time delay is essentially dependent on the speed of sound in the air. For example, when the actuator 8 is arranged at a location da away from the location where the vehicle interior noise SPL is measured, it can be expressed by Equation 18 using the sound velocity Vs in the air.

  Second, the delay time can be estimated from the speed of signal processing. The system can be specified by measuring the input signal and the output signal. Therefore, the time difference between the input signal and the output signal can be calculated.

  Third, after acquiring the transfer model G (s) by specifying the system, the delay time can be estimated together with the unstable zero of the transfer model G.

A general transfer function G (s) including the delay time T is obtained by Equation 19.

Since the transfer function G (s) includes a delay time T, the ideal transfer function N (s) / D (s) includes an unstable zero in N (s), resulting in a stable zero. Including. N (s) is decomposed as shown in Equation 20.

[N] represents a part of N (s) having a stable zero, and N ′ represents another part of N (s) including an unstable zero. Therefore, Equation 19 becomes Equation 21.

Equation 21 can be transformed into Equation 22.

[N] (s) is a stabilized [N] (-s), for example, the root of [N] (-s) is relative to the root of [N] (s).

[G] is a transfer function G (s) in which the numerator is stable, and the all-pass transfer function [N] (− s) / [N] (s) is a well-known Padé approximation used in the approximation of the delay term. (Pade approximation). The delay time term is shown in Equation 24.

  The poles of G ′ (s) and G (s) are the same. Since there is no unstable zero in the transfer function, G ′ (s) is a “minimum phase” and is different from G (s) called a non-minimum phase transfer function. .

  Next, the control efficiency of the controller having the noise estimation unit E compensated for the delay time is analyzed. First, the control efficiency is actually analyzed using a microphone. At this time, the noise estimation unit E is not used. Next, the control efficiency of the controller using the noise estimation unit E that is not compensated for the delay time is analyzed. Finally, the control efficiency of the controller using the noise estimation unit E for which the delay time compensation has been performed is analyzed. In addition, said analysis is implemented about the system which consists of one actuator, one disturbance (acceleration sensor), and one vehicle interior noise SPL.

First, the control efficiency of a system using a microphone is analyzed. FIG. 24 shows a configuration of an active vibration control apparatus including a microphone that actually measures the vehicle interior noise SPL. The vehicle interior noise SPL is obtained by Equation 25.

A control command signal V output for the controller C to drive the actuator is obtained by Equation 26.

Combining Equations 25 and 26, SPL becomes Equation 27.

Further deformation yields Equation 28.

  The above SPL (s) does not appear in the transfer function H (s). However, the denominator and numerator include delay times Ta and Td, respectively. This typical form is known to be difficult to control. Specifically, the gain of the controller C cannot be increased, and there is a high risk of divergence.

  Next, the control efficiency is analyzed for a system including a virtual microphone without delay time compensation.

FIG. 25 shows an active vibration control apparatus including a virtual microphone (noise estimation unit) without delay time compensation. The transmission models 14 and 15 in the noise estimation unit 32a are estimated by specifying the plant 5, for example. The vehicle interior noise SPL shown in Equation 27 is the same. However, the control command signal V for driving the actuator 8 output from the controller C is expressed by Equation 29.

Here, SPL is expressed by Equation 30.

Therefore, the control command signal V is expressed by Equation 31.

Then, SPL (s) in Expression 15 becomes Expression 32.

  Although no time delay appears in the transfer function H, delay times appear in the denominator and numerator, respectively. Further, since there is a problem in the system using the actual microphone as described above, the control efficiency of the controller C remains low. Therefore, a noise estimation unit E that is compensated for delay time is desired as shown below.

  Finally, control efficiency is analyzed for a system with a virtual microphone with delay time compensation.

FIG. 26 shows an active vibration control apparatus including a virtual microphone (noise estimation unit 32c) having a delay time compensation. The control command signal V here is expressed by Equation 33.

The estimated vehicle interior noise [SPL] is expressed by Equation 34.

SPL (s) in Expression 25 is expressed in Expression 35.

The denominator of [H] (s) has a delay time smaller than H (s) and H (s). When the delay time compensation τ and the delay time Ta are equal, the time delay is completely deleted, and SPL (s) is expressed by Equation 36.

<Modification of Third Embodiment>
In the third embodiment, the noise estimation unit E in the system including one actuator 8, one disturbance, and one vehicle interior noise SPL has been described. However, the active vibration control illustrated in FIGS. The apparatus is applicable to a system including two or more actuators, a disturbance, and a vehicle interior noise SPL. That is, it is possible to easily expand a system in which two or more actuators and acceleration sensors are arranged on the floor panel and noise estimation is performed for noise at a plurality of locations in the vehicle interior.

Specifically, when using Na actuators and Nd disturbances (acceleration sensors), the delay time-compensated j-th vehicle interior noise [SPL] j is given by Equation 37.

Here, Vi represents a control command signal to the i-th actuator, [G] a, ij represents a transfer function not including a delay time from the i-th actuator to the j-th vehicle interior noise SPL, and e ^{−. s (Ta, ij-τij)} represents a delay time from the i-th actuator to the j-th vehicle interior noise SPL, which is compensated by the delay time compensation τij. [G] d, kj represents a transfer function that does not include a delay time from the kth disturbance to the jth vehicle interior noise SPL, and e ^{−s (Td, kj−τij)} represents the jth disturbance from the kth disturbance. This is the delay time to the vehicle interior noise SPL and compensated by the delay time compensation τij. Dk (s) represents a kth disturbance signal, that is, a signal output from the acceleration sensor. FIG. 29 shows the configuration of the noise estimation unit E for obtaining the vehicle interior noise SPLij in a system including Nd disturbances.

<Experimental example of delay compensation efficiency>
The noise estimation unit E compensated for the delay time and the controller unit C including the same will be described.

  The position of the right ear of the driver of the vehicle is the noise control target. One piezo actuator 8 is placed on the tank panel 19 of the floor panel 6, and is formed by a shaker that vibrates a location where the disturbance is linked to the control target position. The disturbance signal forms a Gaussian distribution. The controller C is intended to remove noise in a frequency band having a center frequency of 110 Hz. The experimental results are shown in FIGS. 27 and 28 are obtained for the same system (plant 5), but the noise estimation unit E and the controller C are different from each other.

  First, in the experiment of FIG. 27, the noise estimation unit E has all the time delays and no delay time compensation. Noise removal efficiency reaches a maximum of 15 dB, and the frequency band in which noise removal is functioning effectively is approximately 107 to 120 Hz.

  Next, in the experiment shown in FIG. 28, the noise estimation unit [E] has a delay time when the delay time Ta is equal to the delay time compensation τ. The maximum value of noise removal is 18 dB, and the frequency band in which noise removal is functioning effectively is approximately 80 to 130 Hz.

  Such an experimental example showed the advantage of delay time compensation. In other words, by adding the delay time compensation, it is possible to widen the frequency band in which noise removal functions effectively, and to improve noise removal efficiency.

  As described above, according to the third embodiment of the present invention, the following operational effects can be obtained.

  The noise estimation unit 32 takes into account the first delay time Td from the vibration at the position where the sensor is attached to the vehicle interior noise, and the second delay time Ta from the control command signal to the vehicle interior noise. The vehicle interior noise after the first delay time and after the second delay time is estimated. As a result, the vehicle interior noise can be estimated more realistically.

  The second delay time Ta is the shortest delay time among the delay times from the control command signal to the vehicle interior noise. Thus, better control efficiency can be realized by compensating the delay time and estimating the vehicle interior noise SPL based on a delay time shorter than the delay time actually generated in the vehicle body.

  The first delay time Td is obtained by correcting the second delay time Ta. The calculation load of the delay time is reduced, and the delay time can be calculated by an easy algorithm.

  When there are a plurality of actuators, the second delay time Ta is individually set for each actuator. Thereby, the delay time about each of a plurality of vibration transmission paths can be set.

(Fourth embodiment)
According to the active vibration noise control apparatus according to the first to third embodiments, road noise can be separated from other sounds (radio, passenger voice, wind, rain, etc.). Inconsistency between the noise [SPL] estimated by the noise estimation unit E and the actual noise SPL may be a problem.

  Therefore, in the fourth embodiment, a technique for actually measuring the noise SPL using a microphone and updating the transmission model included in the noise estimation unit E will be described. The problem here is at what timing the transmission model is updated.

  When the transmission model included in the noise estimation unit E completely matches the actual transmission model, the estimated noise [SPL] exactly matches the actual noise SPL. However, for the following two reasons, they do not necessarily match.

  First, there are two types of errors that the noise estimator has. Road surface vibrations are not directly accessible and are approximated using floor panel vibrations. Furthermore, since the number of vibration measurement points on the floor panel is limited, the measured data does not include all information about road vibration. This is the first error. The second error is that the transmission model used in the noise estimation unit E is only a counterpart of the actual system, and there are limits to the number of transmission modes and the accuracy of the transmission model. .

  Since the actual noise SPL is mixed with other sounds (radio, occupant's voice, wind, rain, etc.) that have nothing to do with road vibration, there is a difference between the estimated noise and the actual noise. Relevance is low.

  Therefore, it is necessary to update the transmission model in the noise estimation unit E. Here, updating using coherence will be described. This update can be classified into two stages. The first stage is a stage in which it is determined to update the transfer model using the coherence function. The second stage is a stage where the transmission model is actually updated using the output of the noise estimation unit E and the output of the actual microphone.

  With respect to the first stage of determining the update, conventionally, the update time is determined based on an external event. For example, in Japanese Patent Application Laid-Open No. 2000-120768, the time before the door is closed is set as the update time. The transmission model is updated only when a predetermined external matter occurs.

  On the other hand, in this embodiment, the system automatically determines when to update and when not to update. Specifically, the vehicle interior noise [SPL] estimated by the noise estimation unit at a plurality of points is compared with the vehicle interior noise SPL actually measured using a microphone to determine the update time.

  A coherence function Cs (f) between the estimated sound pressure [SPL] and the measured sound pressure SPL in the frequency band to be controlled is calculated. When the coherence function is large, for example, 0.9 or more, ideally close to 1.0, the estimated sound pressure [SPL] and the actually measured sound pressure SPL are linearly related and mixed with road noise. It means that there is no other sound (wind, occupant's voice, etc.). Therefore, in this case, the transmission model of the noise estimation unit can be effectively updated.

  The discrepancy between the transfer model G of the noise estimation unit and the actual system does not affect the coherence function Cs (f), and only sounds other than road noise that can be included in the measured sound pressure SPL are included in the coherence function Cs (f). Influence. For example, the coherence function Cs (f) becomes lower than 1.0 and is almost close to 0. The fact that the estimated sound pressure [SPL] and the measured sound pressure SPL do not exactly match does not affect the coherence function Cs (f).

  One advantage of calculating the coherence function Cs (f) between the estimated sound pressure [SPL] and the measured sound pressure SPL is to measure the coherence function between the vibration αi and the measured sound pressure SPL at all points on the floor panel. Compared with the case where it does, the burden with respect to a calculation and the burden with respect to a storage capacity are reduced extremely.

  FIG. 30 illustrates a noise estimation unit 32 including n first transmission models 14-1 to 14-n and m second transmission models 15-1 to 15-m. n acceleration sensors measure vibrations α1 to αn, and m actuators (control command signals V1 to Vm) are used for active noise control.

One coherence function Cs (f) can be used when the estimated sound pressure [SPL] is used.

  Here, x represents an input signal (estimated sound pressure [SPL]), and y represents an output signal (measured sound pressure SPL). Pxx (f) is the self spectrum of the signal x (t), Pyy (f) is the self spectrum of the signal y (t), and Pxy (f) is the cross spectrum of the signal x (t) and the signal y (t) at the frequency f. Indicates. All these spectra can be calculated, for example, by the Welch method. The signal is measured for 1 second at a predetermined sampling frequency, for example.

When a plurality of input signals are used, a plurality of coherence functions Cm are required as shown in Equation 39. The computational burden and the required storage capacity are very large compared to a single coherence function.

Here, Sxy (f) and Sxx (f) are as shown in Equation 40.

  k indicates the number of input signals, and is n when control is not performed and only n acceleration sensors are used, and control is performed and n acceleration sensors and m actuators are used. N + m. Obviously, it is sufficient to calculate one coherence function Cs without calculating a plurality of coherence functions Cm. Therefore, one coherence function Cs (f) is calculated from the actually measured sound pressure SPL actually measured by the microphone and the estimated sound pressure [SPL] estimated by the virtual microphone (noise estimation unit).

Once the update decision is made, the update itself is done in a very common way. However, updating can be performed even when control is being performed. This is because part of the estimated sound pressure [SPL] corresponds to the control vibration by the actuator (this is referred to as SPLa), and this is included in the virtual microphone as shown in FIG. The estimated sound pressure [SPL] is expressed by Equation 41.

  When the control is not performed, the control command signals V1 to Vm to the actuator are all zero. Therefore, the SPLa term disappears. Updates can be made even when control is not being performed.

  The update model K (s) will be described. The update model K (s) is applied to SPLα corresponding to floor panel vibration in the estimated noise [SPL]. This is for the following two reasons.

  First, when no control is taking place, signal SPLa is approximately equal to zero. Therefore, the update of the portion corresponding to the signal SPLa is not appropriate.

  Second, SPLα represents an unreliable result among the estimated noise [SPL]. This part uses vibration αi at several points on the floor panel, and represents road vibration that becomes road noise in the passenger compartment. Further, the first transfer model Gαi is obtained from experimental data obtained by specifying the system. Thus, there is an unavoidable difference between the first transfer model Gαi and the actual system.

For these two reasons, the update model K (s) is applied to the part of the signal SPLα. Therefore, the estimated sound pressure [SPL] is expressed by Equation 42.

  FIG. 31 is a block diagram illustrating a configuration of the model update unit 61 that incorporates the update model 64.

Next, the calculation unit 63 that calculates the update model K will be described. When the determination unit 62 determines to update, the update model K is calculated using the measured sound pressure SPL as shown in Equation 43.

When this is transformed, the following equation 44 is obtained.

  The update model K can be viewed as a transfer function between the measured sound pressure SPL and the portion SPLα related to the road surface vibration of the noise estimation unit. The update model K (s) can be calculated by a well-known specification technique of single input-single output.

  As shown in FIG. 31, in the third embodiment, a model update unit 61 is added to the subsequent stage of the first transfer model Gα. The model update unit 61 includes a determination unit 62 and a calculation unit 63. The determination unit 62 determines whether or not to update the update model K by calculating a coherence function between the estimated sound pressure [SPL] and the actually measured sound pressure SPL. The calculation unit 63 calculates and updates the update model K when the determination unit 62 determines to update.

  The update algorithm is as follows. (1) First, the measured sound pressure SPL is measured using a microphone at every sampling time n. (2) The coherence function C between the measured sound pressure SPL and the estimated sound pressure [SPL] is calculated every T seconds. (3) The coherence function C is compared with a predetermined threshold Ct to determine whether to update. If C is larger than Ct, update is determined and the process proceeds to the next stage. If C is equal to or less than Ct, no update is performed. (4) When control is performed, the update model K (s) is updated using the measured sound pressures SPL, SPLα, and SPLa. Note that the update model K (s) is initialized to gain 1.

  A specific example of the above algorithm will be shown. Here, no control is performed. That is, SPLa is zero. The number of acceleration sensors is 1, and there is one SPL measurement point. Therefore, the system is represented by a single-input single-output model.

  A first transfer model Gα is calculated using one set of data and is installed in the noise estimation unit. The output signal α from the acceleration sensor is input to the first transmission model Gα, and the estimated sound pressure [SPL] is output.

  As shown in FIG. 32, the estimated sound pressure [SPL] is compared with the actually measured sound pressure SPL using another set of data. Even if the estimated sound pressure [SPL] and the actually measured sound pressure SPL are very close, the gains do not exactly match. Therefore, updating is performed to improve noise estimation, that is, control efficiency.

  As described above, when the coherence function C is larger than the predetermined threshold Ct in the frequency band to be controlled, the update model K is updated. The theoretical threshold Ct is approximately equal to 1.

  FIG. 33 shows an example of the calculation result of the coherence function C. Here, the frequency band to be controlled is 80 to 230 Hz. Since the coherence function C is very close to 1 in this control target frequency band, it can be seen that the update model K can be updated. Note that the coherence function at 0 to 80 Hz and 250 to 1000 Hz is very low. Therefore, the calculation of K can be performed by Equation 44.

  As described above, according to the fourth embodiment of the present invention, the following operational effects can be obtained.

  A microphone for measuring the noise in the housing is arranged, and the first transmission model is updated using the vehicle interior noise measured by the microphone and the vehicle interior noise estimated by the noise estimation unit 32. Thereby, the problem that the noise [SPL] estimated by the noise estimation unit E does not match the actual noise SPL can be solved.

  The first transfer model is updated only when the value of the coherence function C between the vehicle interior noise measured by the microphone and the vehicle interior noise estimated by the noise estimation unit 32 is greater than or equal to a predetermined value. Since the update is performed only when the update is necessary, the update can be performed efficiently.

  Only when the value of the coherence function C between the vehicle interior noise SPL measured by the microphone and the vehicle interior noise [SPL] estimated by the noise estimation unit 32 is a predetermined value or more in a predetermined frequency band. Update the first transmission model. By limiting the frequency band of the target coherence function C, more efficient updating can be performed.

  As described above, the present invention has been described with reference to the four embodiments. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art. That is, it should be understood that the present invention includes various embodiments not described herein. Therefore, the present invention is limited only by the invention specifying matters according to the scope of claims reasonable from this disclosure.

1 is a block diagram showing an overall configuration of an active vibration noise control apparatus according to a first embodiment of the present invention. It is a perspective view which shows the main propagation path | route of the vibration of the tire and vehicle body by the influence of the unevenness | corrugation of a road surface, and the noise in a vehicle interior. It is a block diagram for control system design. It is a block diagram which shows the structure of the noise estimation part 32 of FIG. It is a flowchart which shows the noise estimation procedure by the noise estimation part 32 of FIG. 6 is a graph comparing vehicle interior noise actually measured with vehicle interior noise estimated by the noise estimation unit 32. It is a graph which shows the change of the coherence of the measurement sound pressure by the presence or absence of the 3rd transmission model 16 in the noise estimation part 32 of FIG. It is a block diagram which shows the whole structure of the feedforward type | mold active vibration control apparatus using a general adaptive filter. It is a block diagram which shows the signal transmission system of the whole system of FIG. It is a flowchart which shows the calculation procedure performed with the adaptive filter 38 of FIG. It is a block diagram which shows the whole structure of the feedforward type | mold active vibration control apparatus concerning 2nd Embodiment. 12 is a flowchart showing a calculation procedure of the controller unit 36 of FIG. 11. It is a block diagram which shows the structure of the noise estimation part 32 at the time of using a some acceleration sensor and actuator. FIG. 14A is a cross-sectional view showing a vehicle on which the active vibration and noise control apparatus according to the third embodiment is mounted, and FIG. 14B is a plan view showing a floor panel portion of the vehicle. It is a top view which shows the member arrange | positioned on the floor panel of FIG.14 (b). It is a block diagram which shows the active vibration noise control apparatus of the type which arrange | positions a microphone in a vehicle interior and measures vehicle interior noise. It is a block diagram which shows the active vibration noise control apparatus of the type which estimates vehicle interior noise from the vibration of a floor panel. It is a block diagram which shows the structure of the controller unit 30 using the noise estimation part 32 concerning 3rd Embodiment. It is a block diagram which shows the internal structure of the noise estimation part 32 of FIG. It is a block diagram which shows the internal structure of the noise estimation part 32b which considered the time delay. It is a block diagram which shows the system which consists of one actuator 8, one disturbance (acceleration sensor 7), and one vehicle interior noise SPL. It is a block diagram which shows the internal structure of the noise estimation part 32c which compensated the time delay. It is a block diagram which shows the system which consists of one actuator 8, one disturbance (acceleration sensor 7), and one vehicle interior noise SPL. It is a block diagram which shows an active vibration control apparatus provided with an actual microphone. It is a block diagram which shows an active-vibration control apparatus provided with a virtual microphone (noise estimation part) without a delay time compensation. It is a block diagram which shows an active vibration control apparatus provided with what is a virtual microphone (noise estimation part) and has delay time compensation. It is a graph which shows the sound pressure level for every frequency when delay time compensation is not carried out, and shows the case where a solid line is performing active control, and the case where a dotted line is not performing active control. It is a graph which shows the sound pressure level for every frequency when delay time compensation is carried out, and the case where a solid line is performing active control, and the case where a dotted line is not performing active control are shown. The structure of the noise estimation part E which calculates | requires the vehicle interior noise SPLij in the system containing Nd disturbance is shown. It is a block diagram which shows the noise estimation part 32 provided with n 1st transmission models 14-1 to 14-n and m 2nd transmission models 15-1 to 15-m. It is a block diagram which shows the structure of the model update part 61 which took in the update model 64. FIG. It is a graph which compares estimated sound pressure [SPL] and measured sound pressure SPL. 6 is a graph illustrating an example of a calculation result of a coherence function C.

Explanation of symbols

4 ... Tire 5 ... Car body (housing)
6 ... Floor panel 7, 39 ... Acceleration sensor (sensor)
DESCRIPTION OF SYMBOLS 8 ... Actuator 9 ... Interior space 10 ... Engine 14, 14b ... 1st transmission model 15, 15b ... 2nd transmission model 16 ... 3rd transmission model 17 ... Cabin floor 18 ... Tank panel 19 ... Spare tire panel 20a ˜20d... Vertical member 21a to 21d .. Horizontal member 30, 36... Controller unit 31, 34, 43... Controller (signal calculation means)
32, 32, 32a, 32b, 32c ... noise estimation unit (noise estimation means)
33a, 33b, 33c ... Amplifier 35 ... Transfer function model 37 ... Adaptive law calculation unit 38 ... Adaptive filter 40,54 ... Microphone 41 ... First vibration propagation path 42 ... Second vibration propagation path 44,44b ... First Delay time model 45, 45b ... Second delay time model 61 ... Model update unit 62 ... Determination unit 63 ... Calculation unit 64 ... Update model

Claims (13)

A housing that transmits vibration from outside to inside as noise,
A sensor for detecting vibration of the housing;
An actuator that generates control vibration in the housing;
Signal calculation means for generating a control command signal to the actuator so as to reduce noise in the housing;
An active vibration noise control device comprising: noise estimation means for estimating the noise in the housing using the output signal of the sensor and the control command signal.   The noise estimation means includes a first transfer model representing a transfer characteristic from vibration to a noise in the casing at a position where the sensor is attached, and a second transfer characteristic from the control command signal to the noise in the casing. The active vibration and noise control apparatus according to claim 1, wherein a transmission model of the vibration is stored.   The noise estimation means is a sum of an output value obtained by inputting the output signal of the sensor to the first transfer model and an output value obtained by inputting the control command signal to the second transfer model. The active vibration noise control apparatus according to claim 2, wherein:   The noise estimation means outputs an output obtained by inputting a signal obtained by subtracting a vibration component generated by the actuator from the output signal of the sensor to the first transmission model, and the control command signal as the second control signal. 3. The active vibration noise control apparatus according to claim 2, wherein a sum of outputs obtained by inputting to the transmission model is output as the in-casing noise. The noise estimation means further includes a third transfer model indicating transfer characteristics from the control command signal to vibration at a position where the sensor is attached,
An output obtained by inputting a signal obtained by subtracting the output of the third transfer model from the output signal of the sensor to the first transfer model, and an input obtained by inputting the control command signal to the second transfer model. The active vibration noise control apparatus according to claim 2, wherein the sum of the output and the output is output as the noise in the housing.   The active vibration noise control device according to claim 1, wherein the housing is a vehicle body, and the sensor and the actuator are arranged on a floor panel of the vehicle body.   The noise estimation means takes into account a first delay time from vibration at the position where the sensor is mounted to noise in the housing, and a second delay time from the control command signal to noise in the housing. The active vibration noise control apparatus according to any one of claims 1 to 6, wherein the noise in the housing after the first delay time and after the second delay time is estimated.   8. The active vibration noise control device according to claim 7, wherein the second delay time is a shortest shortest delay time among delay times from the control command signal to the in-casing noise.   The active vibration noise control apparatus according to claim 7 or 8, wherein the first delay time is obtained by correcting the second delay time.   10. The active vibration noise control device according to claim 7, wherein when there are a plurality of actuators, the second delay time is individually set for each actuator. 11. A microphone for measuring the noise in the housing;
The apparatus further comprises: a model updating unit that updates the first transmission model using the in-casing noise measured by the microphone and the in-casing noise estimated by the noise estimation unit. The active vibration noise control apparatus according to any one of 1 to 10.   The model update unit is configured so that the first update is performed only when a value of a coherence function between the noise in the casing measured by the microphone and the noise in the casing estimated by the noise estimation unit is equal to or greater than a predetermined value. The active vibration and noise control apparatus according to claim 11, wherein the transmission model is updated.   The model updating unit has a coherence function value between the in-casing noise measured by the microphone and the in-casing noise estimated by the noise estimating means in a predetermined frequency band equal to or greater than a predetermined value. 12. The active vibration noise control device according to claim 11, wherein the first transmission model is updated only occasionally.

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