JP2789876B2 - Active noise control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active noise control in which a control sound from a control sound source is generated in a predetermined space where noise from a noise source is transmitted, and the noise is attenuated by interfering the two. Related to the device.

[0002]

2. Description of the Related Art As a conventional active noise control device, for example, a device described in Japanese Patent Application Laid-Open Publication No. 1-501344 and British Patent Publication No. 2149614 is known. These devices are applied to a cabin of an aircraft or a similar closed space, and include a plurality of loudspeakers (control sound sources) and microphones (residual noise detecting means) disposed in the closed space and a closed space. Frequency detecting means for detecting the frequency of a single noise source such as an engine located outside; detecting signals from the plurality of microphones; and driving the plurality of loudspeakers based on the detecting signals from the frequency detecting means. It has a signal output device for controlling, and performs adaptive control so as to minimize the evaluation function using, for example, a sum of squares of detection signals (sound pressures) of a plurality of microphones as an evaluation function. As a result, the control sound emitted from the loudspeaker and the noise transmitted from the noise source interfere with each other to attenuate the noise energy, thereby minimizing the sound pressure level in the closed space.

[0003]

However, in the conventional active vibration control device, a plurality of control sound sources (loudspeakers) and a plurality of microphones are arranged in one closed space, and these are connected to one Although the control unit controls the noise to reduce the noise in the entire closed space, it is not a noise attenuation control for each individual boarding space, but to reduce the overall noise level in the closed space. However, there is an unsolved problem that there is a certain limit to the reduction of noise in a passenger space, and the noise cannot be reduced to a sound pressure level according to the occupant's preference.

The present invention has been made in view of the above-mentioned unsolved problems of the prior art. By reducing the noise reduction effect in the region where the occupant is absent, the noise attenuation effect is reduced in the region where the occupant is present. It is an object of the present invention to provide an active noise control device capable of forming a more comfortable acoustic space by concentrating.

[0005]

In order to achieve the above object, an active noise control apparatus according to the first aspect of the present invention, as shown in FIG. 1, reduces noise transmitted from a noise source in a predetermined space. A control sound source that generates an interfering control sound, a plurality of residual noise detecting means for detecting residual noise in the predetermined space, a noise generating state detecting means for detecting a noise generating state of the noise source, and the noise generating state Control means for outputting a drive signal for driving the control sound source so as to minimize the sum of squares of the detection values of the residual noise detection means as an evaluation function based on the detection values of the detection means and the residual noise detection means. in the active noise control system, the detection of the boarding detection means and the residual noise detecting means those該検outlet point near came to have detected the occupant away on the boarding detection unit only when the vehicle starts running to detect the occupant riding condition Rating of value It is characterized in that a cost function weight changing means for changing reduced weight to be given to the function.

The active noise control device according to the second aspect of the present invention includes , as shown in FIG. 2, a control sound source that generates a control sound that interferes with noise transmitted from a noise source in a predetermined space; A plurality of residual noise detecting means for individually detecting residual noise above and below a seat in a predetermined space; a noise generating state detecting means for detecting a noise generating state of the noise source; a noise generating state detecting means and a residual noise detecting means Control means for outputting a drive signal for driving the control sound source so as to minimize the sum of squares of the detection value of the residual noise detection means as an evaluation function based on the detection value of the means. A tilt state detecting means for detecting a tilt state of a seat, and an evaluation function weight changing means for changing a weight given to an evaluation function of a detection value of the upper and lower residual noise detecting means in accordance with a detection value of the tilt state detecting means. It is characterized by comprising and.

[0007] Furthermore, the active noise control apparatus according to claim 3, as shown in FIG. 3, a control sound source for generating the interfering control sound with respect to the noise transmitted from the noise source within a predetermined space, A plurality of residual noise detecting means for detecting residual noise in the predetermined space; a noise generating state detecting means for detecting a noise generating state of the noise source; and a detection value of the noise generating state detecting means and the residual noise detecting means. And a control means for outputting a drive signal for driving the control sound source so as to minimize the sum of squares of the detection values of the residual noise detection means as an evaluation function based on the horizontal rotation of the seat. A rotational position detecting means for detecting a position; and an evaluation function weight changing means for changing a weight given to an evaluation function of a detection value of the preceding and following residual noise detecting means in accordance with a detection value of the rotational position detecting means. It is characterized by a door.

[0008]

In the active noise control apparatus according to the first aspect, the occupant state such as the seating position of the occupant is detected by the occupant detection means, and the occupant is only detected by the evaluation function weight changing means when the vehicle starts running. By reducing the weight given to the evaluation function of the detection value of the residual noise detection means near the detection point where is absent,
The noise attenuation effect near the detection point where the occupant is absent is reduced, the noise attenuation effect at the position where the occupant is present is increased to create a comfortable acoustic space , and the vehicle is stopped and running.
The generation of abnormal sounds due to the fluctuation of the evaluation function during the line is prevented .

Further, in the active noise control apparatus according to claim 2 detects the tilt of the seat seats tilt detecting means to estimate the head position of the seated person, distribution vertically based on the estimated result By changing the weight given to the evaluation function of the provided residual noise detecting means, an appropriate noise attenuation effect is exerted at the position of the occupant's head.

[0010] Furthermore, the active noise control apparatus according to claim 3, as a boxcar, when the seat is possible horizontal rotation, by detecting the rotational position of the seat at the rotational position detection means, By estimating the head position of the occupant and changing the weight given to the evaluation function of the residual noise detection means arranged before and after based on the estimation result, an accurate noise attenuation effect can be obtained at the head position of the occupant. To demonstrate.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 4 is a schematic configuration diagram showing one embodiment when the present invention is applied to a vehicle equipped with a four-cylinder engine. In FIG. 4, reference numeral 1 denotes a vehicle body, and a four-cylinder engine 3 as a noise source is disposed in front of a vehicle compartment 2. Inside the cabin 2, for example, the front left seat 8FL and the front right seat 8F
Loudspeakers 5a and 5b, which also serve as control sound sources for outputting audio signals, respectively, are disposed on the floor panel below R with their vibrating membranes directed upward, and are further provided on the seat back SB of each of the ceiling seats 8FL to 8RR. Microphones 6FL-6 as residual noise detection means at corresponding positions
An RR is provided.

The engine 3 is provided with a crank angle sensor 7 as noise generation state detecting means. The crank angle sensor 7 outputs a reference signal consisting of a sine wave signal of one cycle every time the crankshaft rotates 180 degrees, for example. A crank angle detection signal X is output as a signal. Further, seat sensors 9FL to 9RR as occupant detection means configured by, for example, pressure-sensitive elements for detecting the occupant's seat are embedded in the seat cushion SC of each of the seats 8FL to 8RR. A seating detection signal S _FL that is turned on, for example, when seated, and turned off when not seated.
ＳS _RR is output.

Then, the residual noise detection signals e _{1 to} e ₄ output from the microphones 6FL to 6RR are input to the controller 15, the crank angle detection signal X of the crank angle sensor 7 and the seating detection of the seating sensors 9FL to 9RR. The signals S _{FL to} S _RR are also input to the controller 15.
As shown in FIG. 5, the controller 15 converts the crank angle detection signal X from analog to digital and outputs it.
When an amplifier 22FL-22RR for amplifying the residual noise detecting signals e ₁ to e ₄ microphones 6FL to 6RR, A / D converter to an amplified output is A / D converted outputs of these amplifiers 22FL-22RR 23FL～23RR When the seating detection signal S _FL to S conversion output and the seating sensors 9FL~9RR of each a / D conversion circuit 21,23FL~23RR
A microcomputer 26 to which _RR is input, and a loudspeaker 5 output from this microcomputer 26
a, loud amplifies 5b of the drive signals y _1, y ₂ and D / A converted and output to D / A conversion circuit 27a, and 27b, these D / A conversion circuit 27a, an analog signal output from 27b An amplifier 29a that supplies the speakers 5a and 5b,
29b.

The microcomputer 26 always operates sequentially.
Filter coefficient W to be updated_miAs a reference signal based on
Convolution operation of the crank angle detection signal X of
Drive signal y for speaker 5a, 5b_1,y_TwoCalculate
Adaptive digital filter processing and crank angle detection signal
Space transmission between microphone and speaker based on signal X
Model space transfer modeled according to the number of function combinations
Criteria filtered by the filter coefficients corresponding to the function
Signal r_km(See equation (6) below)
Filtering and the filtered reference signal r_km
And residual noise detection signal e₁ ~ E_FourAnd adaptive digital based on
Filter coefficient W in filter processing _miTo LMS (Lea
st MeanSquare)
Data updating process and the seating sensor 9FL.
To 9RR seating detection signal S_FL~ S_RRFilter based on
Change the weight coefficient of the evaluation function J when updating the coefficient
Therefore, the noise attenuation effect at the position where the occupant is located is
It is controlled so as to be larger than that.

Here, the control principle of the microcomputer 26 will be described using a general formula. Now, the residual noise detecting signals the k-th microphone 6FL~6RR detects e _k (n), the k-th microphone 6F when the control sound from the loudspeakers 5a and 5b (secondary sound) is not
The residual noise detection signals detected by the L to 6RRs are represented by e _pt (n), and the transfer function H _km between the mth loudspeakers 5a and 5b and the kth microphones 6FL to 6RR is represented by FI.
The filter coefficient corresponding to the j-th (j = 0, 1, 2, ──I _c -1) term represented by an R (finite impulse response) function is C _kmj ′, and the crank angle detection signal is X ( n), the coefficient of this type the crank angle detection signal X (n) i-th adaptive digital filter for driving the m-th loudspeaker 5a and _{5b (i = 0,1,2, ─I F} -1) To W _mi
Then, the following equation (1) is established.

[0016] Here, each term with (n) is a sample value at sampling time n, and K is the microphone 6F
The numbers L to 6RR (four in this embodiment), M is the number of loudspeakers 5a and 5b (two in this embodiment), and I _C is F
Tap number of IR digital filter coefficients C _miles expressed in the filter '(filter order), a I _F is the number of taps of the filter coefficient W _mi represented in the adaptive digital filter (filter order).

In the above equation (1), “｛ΣW _mi · X (nj
-i) The term “｝” (= y _m ) represents the output when the crank angle detection signal X is subjected to the adaptive digital filter processing.
Section _{C km j · {ΣW mi ·} X (nji)} "is the signal energy input to the m-th speaker 5a and 5b is output as the acoustic energy from these speakers 5a and 5b, spatial transfer function of the vehicle interior Represents a signal at the time of reaching the k-th microphone 6FL to 6RR via C _km ,
Further, the entire second term on the right side of “{C _kmj · {W _mi · X (nji)}] is the k-th microphone 6FL to 6R.
Since the signals reaching R are added for all the speakers, the sum of the secondary sounds reaching the k-th microphones 6FL to 6RR is shown.

Next, an evaluation function J is placed as shown in the following equation (2). In this embodiment, the LMS algorithm is adopted,
A filter coefficient W _mi that minimizes the evaluation function J is obtained, and each filter coefficient W _mi of the adaptive digital filter processing is updated. The LMS algorithm, which is the steepest descent method, uses an n-th value W as a filter coefficient for adaptive digital filtering.
with _mi (n), calculates the gradient ∂J / ∂W _mi of mean square error, which was α multiplied seeking (n + 1) th value W _mi (n + 1), to reduce the value of the evaluation function J Calculation is performed as follows.

The equation for calculating the gradient ∂J / ∂W _{mi is given by} the following equation (2). Then, from the above equation (1), So, Here, the right side of equation (4) is In other words, the gradient of the evaluation function for the filter coefficient ∂J /
∂W _mi is Can be represented by

Therefore, the updating equation of the filter coefficient is given by the following equation (8) including the weight coefficient γ _k . Here, α is a convergence coefficient, which is related to the speed at which the adaptive digital filter processing converges optimally and the stability at that time.

As described above, the filter coefficient W _mi (n + 1) in the adaptive digital filter processing is determined by the microphone 6
FL to residual noise detection signal e ₁ (n) output from 6RR
The residual noise detection signal e ₁ (n) is sequentially updated according to the LMS algorithm based on e ₄ (n) and the crank angle detection signal X (n) from the crank angle sensor 7.
Drive signals y ₁ (n) and y ₂ (n) minimizing ｅe ₄ (n) are formed, and these are supplied to the loudspeakers 5a and 5b, and the cabin 2 is controlled by the control sound output from these speakers. The noise inside is canceled out.

Next, the operation of the above embodiment will be described with reference to the flowchart of FIG. When the key switch is turned on, the power of the entire system is turned on, and the microcomputer 26 executes the timer interrupt processing shown in FIG. 6 every predetermined time (for example, 1 msec). First, read the seating detection signal S _FL to S _RR of the seating sensors 9FL~9RR in step S1, then the processing proceeds to step S2, the seating detection signal S _FL is determined whether the ON state, which is turned on Is satisfied, the process proceeds to step S3 to set a weighting coefficient a of an evaluation function, which will be described later, to "1".
When it is in the off state, the process proceeds to step S4, where the weight coefficient a is set to "0", and then the process proceeds to step S5.
Move to

In step S5, it is determined whether or not the seating detection signal _SFR is in the ON state. When the signal is in the ON state, the flow advances to step S6 to set a weighting coefficient b of an evaluation function described later to "1". Then, the process proceeds to step S8, and if it is in the off state, the process proceeds to step S7, where the weight coefficient b is set to "0", and then the process proceeds to step S8.

In step S8, it is determined whether or not the seating detection signal _SRL is in the ON state. When the signal is in the ON state, the flow shifts to step S9 to set a weight coefficient c of an evaluation function described later to "1". Then, the process proceeds to step S11, and if it is in the off state, the process proceeds to step S10 to set the weighting coefficient c to "0", and then proceeds to step S11.

In step S11, it is determined whether or not the seating detection signal _SRR is in the ON state. When the signal is in the ON state, the flow shifts to step S12 to set a weight coefficient c of an evaluation function described later to "1". After that, the process proceeds to step S14, and when it is in the off state, the process proceeds to step S13 to set the weight coefficient d to "0" and then to step S1.
Move to 4.

In step S14, the residual noise detection signal e
₁ to e ₄ and the reference signal X (n) reads, then evaluated by the following calculation equation (9) the process proceeds to step S15 function J
Is calculated. J = ae ₁ (n) ² + be ₂ (n) ² + ce ₃ (n) ² + de ₄ (n) ² where a to d are “1” or “0” as described above. Is a weight coefficient set to "".

Next, the process proceeds to step S16,
Perform digital filter processing corresponding to Eq. (6) and filter
The reference signal r that has been filtered_km, Then step
Proceeding to S17, the calculated filtered reference signal
Number r_kmAnd residual noise detection signal e ₁~ E_ThreeAnd based on said
Perform filter coefficient update processing according to equation (8) to filter
Coefficient W_mi(n + 1) is calculated, and then the process proceeds to step S18.
Then, the calculation of the equation (7) is performed to obtain the filter coefficient W of the evaluation function J.
And the gradient に 対 す る J / ∂W with respect to
It is determined whether or not it has become, and when ∂J / ∂W> ΔJ,
Is the target filter coefficient W that minimizes the evaluation function J._optReached
It is determined that it has not been performed, and the process returns to step S14.
When ∂J / ∂W ≦ ΔJ, the evaluation function J is
Target filter coefficient W_optIs judged to be close enough to
Then, control is passed to step S19.

In step S19, step S18
Adaptive digital filter processing is executed based on the filter coefficient W _mi (n + 1) calculated by
calculating a drive signal y _1, y ₂ with respect to b, then proceeds to the drive signal y ₁ that is _calculated, y ₂ and D / A conversion circuit 27a, and outputs the 27b terminates the timer interrupt processing in step S20 To return to the predetermined main program.

Here, the processing of steps S1 to S13 in FIG.
The processing in step S20 corresponds to the control means. Therefore, assuming that the key switch is turned on and the engine 3 is stopped in an idling state, a noise corresponding to the rotation speed N of the engine 3 is transmitted into the vehicle interior 2. At this time, the vehicle has four occupants, and each seat 8FL to 8
Assuming that all of the seating detection signals S _{FL to} S _RR of each of the seating sensors 9FL to 9RR are in the ON state, when the processing of FIG.
In the process of S13, each of the weight coefficients a to d is set to "1".

For this reason, the evaluation function J calculated in step S15 according to the equation (9) is calculated for each of the seats 8FL to 8R.
R is calculated as the sum of squares of the residual noise detection signals e _{1 to} e ₄ of the microphones 6FL to 6RR corresponding to R,
Based on the residual noise detection signals e _{1 to} e ₄ , the filter coefficients in the adaptive digital filter processing are sequentially updated in accordance with the LMS algorithm, and each residual noise detection signal e ₁
Loudspeaker 5a as evaluation function J to e ₄ are approximately the same evaluation weight is minimized, the drive signal y ₁ for _5b, y ₂ are calculated, which D / A conversion circuit 27a, 2
The signal is supplied to the loudspeakers 5a and 5b via the switch 7b.
Therefore, the drive signals y _1,
control sound corresponding to y ₂ is issued, which by interfering with the noise, noise attenuation in the words all seats 8FL~8RR position as the residual noise detecting signals e ₁ to e ₄ of the microphone 6FL~6RR is minimized The effect is exhibited.

However, when the occupant is sitting only in the driver's seat 8FR, the seating sensor 9 in the driver's seat 8FR
Only the seating detection signal SFR of _FR is turned on, and the seating sensors 9FL, 9FL,
The seat detection signals S _FL, S _{RL, and} S _RR of 9RL and 9RR maintain the off state. Therefore, when the process of FIG. 6 is executed, the process proceeds from step S2 to step S4 to set the weight coefficient a to “0”, and then proceeds from step S5 to step S6 to set the weight coefficient b to “1”. And the remaining weighting factors c and d are set to “0”, and the evaluation function J calculated based on the equation (9) in step S15 faces the driver's seat 8FR. Only the residual noise detection signal e ₂ (n) of the microphone 6FR is set.

Therefore, the seats 8F other than the driver's seat 8FR
L, 8RL, microphone corresponding to these increases noise in 8RR 6FL, 6RL, even a residual noise detection signal e _1, e _3, e ₄ is greater value of 6RR,
These do not affect the evaluation function J. For this reason, the positions of the seats 8FL, 8RL, and 8RR other than the driver's seat 8FR are excluded from the noise suppression control target, and the noise reduction energy can be concentrated on only the driver's seat 8FR and the noise attenuation effect in the driver's seat 8FR. And a comfortable acoustic space can be formed.

Similarly, when the occupant is seated in the driver's seat 8FR and the passenger's seat 8FL, the evaluation function J is calculated by the sum of the squares of the residual noise detection signals e ₁ and e ₂ of the microphones 6FR and 6FL corresponding to these. By setting, a large noise attenuation effect is exerted preferentially on the front seats 8FL and 8FR, and the noise attenuation effect is reduced on the remaining rear seats 8RL and 8RR.

In the first embodiment, the case where the seating sensors 9FL to 9RR are applied as the occupant detecting means has been described. However, the present invention is not limited to this.
Occupant detection means such as an infrared sensor can also be applied,
In addition, when the door close to the microphone is open, it may be determined that the occupant in the vicinity is absent.

Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the weight coefficients a to d in the first embodiment are changed only when the vehicle starts running. That is, as shown in FIG. 7, a step S0 for determining whether or not the vehicle has started running from a stopped state is added before step S1 in FIG. 6. In this step S0, the vehicle is stopped or the vehicle is running. , The process directly proceeds to step S14, except that the process proceeds to step S1 only when the vehicle starts traveling from a stopped state.
The same processing as in FIG. 6 in the embodiment is executed. The weighting coefficients a to d are all set to, for example, “1” by initialization at the start of execution of a predetermined main program.

According to the second embodiment, when the key switch is turned on while the vehicle is stopped, the weighting factors a to d are all initially set to "1" by a predetermined main program. when continues, so the program proceeds from step S0 to step S14, the residual noise detecting signals e ₁ ~ of all microphones 6FL~6RR
e Perform noise suppression control using the sum of squares of ₄ as the evaluation function J,
When the vehicle starts running from a stopped state, step S0
By shifting from step S1 to step S1, an effective noise suppression effect according to the occupant's seating position can be exhibited.

For this reason, when the vehicle is stopped,
The occupant is expected to fluctuate due to getting on and off the passenger, and this fluctuation
The seating detection signals S of the seating sensors 9FL to 9RR_FL
~ S _RRFluctuates, the evaluation function J also fluctuates, and
When it becomes a cause of noise and the noise suppression effect cannot be exhibited effectively
Change of weighting factors a to d while the vehicle is stopped
To prevent the fluctuation of the evaluation function J
More accurate noise suppression control can be performed. Similarly, car
Changes of weighting factors a to d are prohibited even when both are running.
When the occupant sits down and sits down.
The seat detection signals S of the seat sensors 9FL to 9RR_FL~
S_RREven if is temporarily changed, the fluctuation of the evaluation function J
It is possible to maintain a good acoustic space by preventing the sound.

Next, a third embodiment of the present invention will be described with reference to FIGS.
Will be described. In the third embodiment, the noise attenuation target space follows the movement of the occupant's head when the tilt angle of the reclining seat of the vehicle is changed. That is, as shown in FIG. 8, the seat cushion SC of the reclining seats 31F and 31R of the vehicle is provided.
And reclining mechanism 3 provided between seat back SB
2 is provided with tilt angle sensors 33F and 33R for detecting the tilt angle θ of the seat back SB, and a pair of upper and lower microphones 34F _{U and} 34F respectively on the rear side of the seat back SB.
_L and 34R _U, the 34R _L disposed, the tilt angle sensor 33
F, tilt angle detection value theta _F of _33R, theta _R is controller 15
Has been entered.

Then, the noise suppression processing shown in FIG. 9 is executed by the controller 15. That is, step S21
And the tilt angle detection values θ _{F and} θ _R of the tilt angle sensors 33F and 33R.
Is read, and then the process proceeds to step S22, where a tilt angle detection value θ _F, set in advance based on the tilt angle detection values θ _F, θ _{R ,}
theta _R a microphone 34F _U, the weighting factor for the residual noise detecting value e _1U and e _2U of 34R _U a _U, the weight with reference to the map shown in FIG. 10 showing the relationship of b _U coefficient a _U, calculates b _U , and then the process proceeds to step S23, the calculated weighting factor a _U, b below (10) and the _U (11) microphones 34F L _according to formula residual noise detecting value e _1L of 34R _L, e _2L
, Weighting coefficients a _{L and} b _L are calculated.

A _L = 1−a _u (10) b _L = 1−b _U (11) Next, the process proceeds to step S24, and the process proceeds to step S24 in FIG.
14 similarly to the microphone 34F _U, 34F _L and 3
4R _U, the residual noise detecting value e _1U of _{34R L, e 1L, e 2U} , e
_2L and the crank angle detection value X of the crank angle sensor 7 are read, and then the process proceeds to step S25, where the evaluation function is calculated according to the following equation (12) based on the calculated weighting coefficients a _U, a _L, b _{U, and} b _L. Calculate J.

[0041] ^{_{J = a U e 1U 2 +}} a L e 1L 2 + b U e 1U 2 + b L e 1L 2 ............ (12) Thereafter, steps similar to steps S16~S20 in FIG 6 S26 to S30 Do with. According to the third embodiment, for example, the seat back SB is
In the tilt angle theta ₀ is a state close to a vertical state, as shown in FIG. 10, the upper microphone 34F _U, the weighting factor a _U corresponding to 34R _U, b _U is set to "1", the lower the opposite side Weight coefficient a corresponding to microphones 34F _{L and} 34R _L
L, since it is set to b _L is "0", the evaluation is calculated in step S25 function J e _1U ² + e _1U ^2, and the nearest microphone 34F _U seated person's head, the 34R _U residual noise detecting Since only the signals e _1U and e _2U are to be controlled, the position above the seatback SB where the occupant's head is located is set as the noise attenuation target space.

When the reclining mechanism 32 is operated from this state to tilt the seat back SB clockwise,
Upper microphone 34F _U accordingly, the residual noise detecting signal e _1U of 34R _U, the weighting factor for the e _{2U a U,} b _U
Gradually decreases, and conversely, the lower microphone 34F
_L, the residual noise detecting signal e _1L of 34R _L, the weighting factor a _L for e _2L, by b _L gradually increases, following the movement of the passenger's head by tilting of the seat back SB is noise attenuation target space By gradually moving downward, a good acoustic space can be maintained.

Next, a fourth embodiment of the present invention will be described with reference to FIGS.
12 will be described. This fourth embodiment is a
-When the seat is rotatable in a horizontal plane as in
Follows the movement of the occupant's head position as the seat rotates
Thus, the noise attenuation space is moved.
That is, as shown in FIG.
Intermediate seat 4 among the rows of seats 41F, 41M, 41R
When only 1M is configured to be rotatable in the horizontal plane,
Is provided with a rotation angle sensor 42 for detecting the rotation angle δ,
The front and rear fixed seats 41F and 41R have their seat bars.
Microphone at the ceiling position facing the computer SB from above
43F and 43R are provided, and the seat 41M in the middle is provided.
The seat back SB faces 180 degrees on the front-back direction line
When in each of the rotational positions, above the seat back SB
Microphone 43M at the ceiling position facing_F,43M
_RAnd the rotation angle detection value δ of the rotation angle sensor 42 and the
Icrophone 43F, 43M _F,43M_R,The residual noise of 43R
Sound detection value e_1,e_2F,e_2RAnd e_ThreeTo controller 15
Is entered.

Then, the controller 15 executes a noise suppression control process shown in FIG. This noise suppression control process is the same as the noise suppression control process of FIG.
Process 21 is changing the rotation angle detection value δ of the rotational angle sensor 42 to read no step S32, preset rotation angle δ and the residual noise detecting microphone 43M _F step S22 is based on the rotation angle detection value δ Weighting factor b for value e _2F
By referring to a map shown in FIG. 13 in which the relationship between the _F to step S32 to set the weighting factor b _F, step S2
3 is the weight coefficient b _R (= 1−1) from the set weight coefficient b _F.
to step S33 of calculating the b _F), except that the processing of the step S25 is changed to step S35 for calculating an evaluation function J performs the following operation (13) 11
The same processing is performed.

[0045] According to ^{_{J = e 1 2 + b F}} e 2F 2 + b R e 2R 2 + e 3 2 ............ (13) The fourth embodiment, and the seat 41M of middle portion the seat back SB behind When the vehicle is in the forward sitting state, the rotation angle detection value δ of the rotation angle sensor 42 becomes 0 degree,
Therefore, the weight for the residual noise detecting signal e _2F of the front side of the microphone 43M _F rear side of the microphone 43M _R residual noise detecting signal weighting coefficients b _R becomes "1" for the e _2R of which is calculated in step S32, conversely Coefficient b _F
Becomes “0”, so that the evaluation function J is e ₁ ² + e _2R ² + e ₃ ²
Thus, only the rear microphone 43M _R affects the evaluation function J for the middle seat 41M, and the microphone 43M _R position becomes the noise attenuation target space for the seat 41M. , Seat 41M
The noise attenuation target space corresponding to the head of the seated person can be formed.

When the seat 41M is gradually rotated clockwise or counterclockwise up to 180 degrees from this state, the weight coefficient b _R decreases as the rotation angle δ increases, and the weight coefficient b _{R
Since F} increases, the noise attenuation target space gradually moves forward following the movement of the occupant head due to the rotation of the seat 41M, and a good acoustic space can be maintained. In each of the above embodiments, the case where the noise suppression control process is executed by turning on the key switch has been described. However, the present invention is not limited to this, and the engine speed is equal to or less than the predetermined speed. , The noise suppression control processing may be stopped when there is no occupant, that is, when all of the seating detection signals S _{FL to} S _{RR of the} seating sensors 9FL to 9RR are in the off state, and when the door is opened. However, in such a state where the occupant is absent, the occupant's ear position is expected to be different from the normal noise attenuation target space, such as when cleaning the passenger compartment floor panel, etc. Can be prevented.

In each of the above embodiments, a case where a loudspeaker is used as a control sound source has been described. However, the present invention is not limited to this, and a vibrator can be used, and a microphone for detecting residual noise can be used. Instead, an acceleration vibration sensor can be applied. Furthermore, the number of loudspeakers and microphones to be installed is not limited to each of the above embodiments, but may be an arbitrary number of two or more.

Further, in each of the embodiments described above, the case where the engine noise is suppressed has been described. However, the present invention is not limited to this, and the road noise is suppressed by detecting the vibration input from the road surface to the wheel, or the window noise is suppressed. Wind noise can be suppressed by detecting the vibration of the glass, and these complex sounds can also be suppressed. In each of the above embodiments, the case where the microcomputer 26 performs the adaptive digital filter processing and the digital filter processing of the filter coefficient corresponding to the spatial transfer function between the loudspeaker and the microphone has been described. An adaptive digital filter and a digital filter can be applied, and the filter coefficient of the adaptive filter is L
The update may be performed by applying an algorithm other than the MS algorithm.

Further, in each of the above embodiments, the case where the present invention is applied to a vehicle has been described. However, the present invention is not limited to this, and may be applied to a case where vibration including noise in a room such as an aircraft is attenuated.

[0050]

As described above, according to the active noise control device of the first aspect, the presence of the occupant is detected by the occupant detecting means, and the evaluation function weight changing means is used when the vehicle starts running.
The weight for the evaluation function of the residual noise detection signal corresponding to the occupant's absent position is changed to be smaller than that of other positions. As compared to the case where the vehicle exhibits the noise reduction effect, the noise attenuation energy can be concentrated at the position where the occupant is present to enhance the noise attenuation effect. Thus, the effect of preventing the fluctuation of the evaluation function due to the movement of the occupant in the stopped state or the running state can be obtained, and a good noise suppression effect can be exhibited.

Further, according to the active noise control apparatus according to claim 2, when the seat's seat is configured to be tilted, the residual noise detecting means provided in the upper and lower depending on the tilt state Since the weight given to the evaluation function of the residual noise detection signal is changed, it is possible to move the noise attenuation target space by following the vertical movement of the occupant's head due to the tilt of the seat back, providing comfortable sound. The effect that a space can be formed is obtained.

[0052] Furthermore, according to the active noise control apparatus according to claim 3, when the seat is configured to be rotatable in a horizontal plane, the residual noise detecting disposed back and forth in response to the rotational position Since the weight given to the evaluation function of the residual noise detection signal of the means is changed, it is possible to move the noise attenuation target space by following the movement of the occupant's head in the front-rear direction due to the rotation of the seat, which is comfortable. The effect that an acoustic space can be formed is obtained.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram corresponding to claim 1 of the present invention.

FIG. 2 is a basic configuration diagram corresponding to claim 3 of the present invention.

FIG. 3 is a basic configuration diagram corresponding to claim 4 of the present invention.

FIG. 4 is a schematic configuration diagram of a first embodiment of the present invention.

FIG. 5 is a block diagram illustrating an example of a controller.

FIG. 6 is a flowchart illustrating an example of a processing procedure of a microcomputer.

FIG. 7 is a flowchart illustrating an example of a processing procedure of a microcomputer according to a second embodiment of the present invention.

FIG. 8 is a schematic configuration diagram of a third embodiment of the present invention.

FIG. 9 is a flowchart illustrating an example of a processing procedure of a microcomputer according to the third embodiment.

FIG. 10 is an explanatory diagram showing a map representing a relationship between a detected tilt angle θ and weighting coefficients a _{U and} b _U in the third embodiment.

FIG. 11 is a schematic configuration diagram of a fourth embodiment.

FIG. 12 is a flowchart illustrating an example of a processing procedure of a microcomputer according to a fourth embodiment.

13 is an explanatory view showing a map representing the relationship between the rotation angle detection value δ and the weighting factor b _F of the fourth embodiment.

[Explanation of symbols]

2 cabin 3 engine 5a, 5b loudspeaker 6FL~6FR microphone 7 crank angle sensor 8FL~8RR seat 9FL~9RR seating sensor 15 controller 26 microcomputer 31F, 31R seat 32 the reclining mechanism 33F, 33R tilt sensor 34F _U, 34F _L, 34R _U, 34R _L microphone 41F, 41M, 41R Seat 42 Rotation angle sensor 43F, 43MF _, 43M _R, 43R Microphone

Claims (3)

(57) [Claims] 1. A control sound source that generates a control sound that interferes with noise transmitted from a noise source in a predetermined space, a plurality of residual noise detection units detecting residual noise in the predetermined space, and the noise Noise generation state detection means for detecting the noise generation state of the source, and minimizing the sum of squares of the detection values of the residual noise detection means as an evaluation function based on the detection values of the noise generation state detection means and the residual noise detection means An active noise control device including a control means for outputting a drive signal for driving the control sound source, wherein the occupant detection means detects an occupant's riding state, and the occupant detects the occupant only when the vehicle starts running. active noise control instrumentation, characterized in that a cost function weight changing means for changing the weights or give away the evaluation function of the detected value of the residual noise detecting means those該検outlet point near came to have detected small Place. 2. A control sound source that generates a control sound that interferes with noise transmitted from a noise source in a predetermined space, and a plurality of residual noises that individually detect residual noise above and below a seat in the predetermined space. Detection means, a noise generation state detection means for detecting a noise generation state of the noise source, and a detection value of the residual noise detection means as an evaluation function based on the detection values of the noise generation state detection means and the residual noise detection means. An active noise control device including a control unit that outputs a drive signal for driving the control sound source so as to minimize the sum of squares, wherein a tilt state detection unit that detects a tilt state of a seat; and the tilt state detection unit. And an evaluation function weight changing means for changing the weight given to the evaluation function of the detection value of the upper and lower residual noise detection means according to the detection value of the active noise control means. 3. A control sound source for generating a control sound that interferes with noise transmitted from a noise source in a predetermined space, a plurality of residual noise detection means for detecting residual noise in the predetermined space, and the noise Noise generation state detection means for detecting the noise generation state of the source, and minimizing the sum of squares of the detection values of the residual noise detection means as an evaluation function based on the detection values of the noise generation state detection means and the residual noise detection means And a control means for outputting a drive signal for driving the control sound source, a rotation position detection means for detecting a horizontal rotation position of a seat, and a control signal according to a detection value of the rotation position detection means. And an evaluation function weight changing means for changing the weight given to the evaluation function of the detection value of the residual noise detection means before and after.