JPH0561487A - Active type noise controller - Google Patents

Abstract

PURPOSE:To form a comfortable acoustic space by improving a muffling effect in a position in which riding persons exist, in the case the number of riding persons is small. CONSTITUTION:In seats 8FL-8RR of a car room 2 of a vehicle 1, seating sensors 9FL-9RR are placed, and also, microphones 6FL-6RR being residual noise detecting means are placed so as to be opposed to each seat 8FL-8RR, and also, in the car room 2, loudspeakers 5a, 5b being control sound sources are placed. In such a state, by a controller 15, weight coefficients (a)-(d) to an evaluation function J of residual noise detecting signals e1-e4 of the microphones 6FL-6RR corresponding to a turn-off state of seating detecting signals SFL-SRR of the seating sensors 9FL-9RR, that is, the seat on which a person is not seated are made small, a muffling effect to the seat on which a person is seated is made larger than the case a muffling effect is displayed to the whole car room, and a comfortable separate acoustic space is formed.

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 the noise from the noise source is transmitted and the two are interfered with each other to attenuate the noise energy. Regarding the device.

[0002]

2. Description of the Related Art As conventional active noise control devices, for example, the devices described in Japanese Patent Publication No. 1-501344 and British Patent Publication No. 2149614 are known. These devices are applied to an aircraft cabin or a similar closed space, and include a plurality of loudspeakers (control sound sources) and microphones (residual noise detection means) arranged in the closed space, and a closed space. Frequency detection means for detecting the frequency of a single noise source such as an engine located outside, drive signals for the plurality of loudspeakers based on detection signals from the plurality of microphones, and detection signals from the frequency detection means. With a structure including a signal output device for controlling, the sum of squares of detection signals (sound pressures) of a plurality of microphones is used as an evaluation function, and adaptive control is performed so as to minimize this evaluation function. As a result, the control sound radiated from the loudspeaker interferes with the noise transmitted from the noise source to attenuate the noise energy, thereby minimizing the sound pressure level in the closed space.

[0003]

However, in the above-mentioned 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 combined into one. Although the control device controls the noise in the entire closed space, noise reduction control is not performed for each individual riding space, but because the noise level of the entire closed space is reduced, However, there is an unsolved problem that the noise can not be reduced to the sound pressure level according to the occupant's taste because there is a certain limit to the noise reduction in the passenger space.

The present invention has been made by paying attention to the unsolved problem of the above-mentioned conventional example, and by reducing the sound deadening effect in the region where the occupant is absent, a noise damping effect is provided 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 device according to a first aspect of the present invention, as shown in FIG. 1, responds to noise transmitted from a noise source in a predetermined space. A control sound source for generating 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 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 detection values of the detection means and the residual noise detection means. In the active noise control device, the boarding detection means for detecting the occupant's riding state, and the weight given to the evaluation function of the detection value of the residual noise detection means near the detection point when the occupant's absence is detected by the boarding detection means Small It is characterized in that a cost function weight changing means for change without.

Further, the active noise control device according to a second aspect of the present invention is characterized in that the evaluation function weight changing means is configured to change the weight only when the vehicle starts traveling. Further, the active noise control device according to claim 3 is
As shown in FIG. 2, a control sound source that generates a control sound that interferes with a noise transmitted from a noise source in a predetermined space, and a plurality of noise sources that individually detect residual noise above and below the seat in the predetermined space. Residual noise detection means, noise generation state detection means for detecting the noise generation state of the noise source, and detection of residual noise detection means as an evaluation function based on the detection values of the noise generation state detection means and residual noise detection means In an active noise control device including a control means for outputting a drive signal for driving the control sound source so as to minimize the sum of squares of values, a tilting state detecting means for detecting a tilting state of a seat, and the tilting state. An evaluation function weight changing means for changing the weight given to the evaluation function of the detection values of the upper and lower residual noise detecting means according to the detection value of the detecting means is provided.

Further, as shown in FIG. 3, an active noise control device according to a fourth aspect includes 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 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. A horizontal rotation of the seat in an active noise control device having 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. A rotation 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 front and rear residual noise detecting means according to a detection value of the rotation position detecting means. It is characterized in that was.

[0008]

In the active noise control device according to the first aspect, the occupant's seating position and other riding conditions are detected by the occupant detection means, and the evaluation function weight changing means detects residual noise in the vicinity of the detection point where the occupant is absent. By changing the weight given to the evaluation function of the detection value of the means to a small value, the noise attenuation effect near the detection point where the occupant is absent is reduced, and the noise attenuation effect at the position where the occupant is present is increased to provide a comfortable sound. Form a space.

Further, in the active noise control device according to the second aspect of the present invention, the evaluation function weight changing means changes the weight only when the vehicle starts to travel, so that the evaluation function changes while the vehicle is stopped and running. To prevent abnormal noise from being generated. Further, in the active noise control device according to the third aspect, the tilt detection means detects the tilt of the seat to estimate the head position of the seated person, and based on the result of the estimation, the residuals arranged above and below are retained. By changing the weight given to the evaluation function of the noise detecting means, a proper noise damping effect is exhibited at the head position of the occupant.

Further, in the active noise control device according to the fourth aspect, when the seat is horizontally rotatable like a box car, the rotational position of the seat is detected by the rotational position detecting means. By estimating the head position of the occupant and changing the weight given to the evaluation function of the residual noise detecting means arranged before and after based on this estimation result, an accurate noise attenuation effect can be obtained at the head position of the occupant. Bring out.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 4 is a schematic configuration diagram showing an embodiment when the present invention is applied to a vehicle equipped with a 4-cylinder engine. In FIG. 4, reference numeral 1 denotes a vehicle body, and a 4-cylinder engine 3 as a noise source is arranged in front of a vehicle interior 2 of the vehicle body. In the passenger compartment 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, are arranged on the floor panel under R with their vibrating membranes facing upward, and further on the seat back SB of each seat 8FL to 8RR on the ceiling. Microphones 6FL to 6 as residual noise detecting means are provided at corresponding positions, respectively.
RR is provided.

Further, a crank angle sensor 7 as a noise generation state detecting means is attached to the engine 3, and a reference consisting of a sinusoidal signal of one cycle is generated every time the crankshaft rotates 180 degrees from the crank angle sensor 7, for example. A crank angle detection signal X as a signal is output. Further, seating sensors 9FL to 9RR as a passenger detecting means configured by, for example, a pressure-sensitive element that detects seating of an occupant are embedded in the seat cushions SC of the seats 8FL to 8RR. The seating detection signal S _FL is turned on when seated, and turned off when seated
~ S _RR is output.

The residual noise detection signals e _{1 to} e ₄ output from the microphones 6FL to 6RR are input to the controller 15, and the crank angle detection signal X of the crank angle sensor 7 and the seating detection of the seating sensors 9FL to 9RR are detected. The signals S _{FL to} S _RR are also input to the controller 15.
As shown in FIG. 5, the controller 15 performs A / D conversion on the crank angle detection signal X and outputs the A / D conversion circuit 21.
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 And the conversion outputs of the A / D conversion circuits 21, 23FL to 23RR and the seating detection signals S _{FL to} S of the seating sensors 9FL to 9RR.
Microcomputer 26 to which _RR is input, and 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 is always in sequence.
Filter coefficient W to be updated_miAs a reference signal based on
The crank angle detection signal X of
Drive signal y for speaker 5a, 5b_1,y₂Calculate
Adaptive digital filter processing and crank angle detection signal
Space transmission between microphone and speaker based on No. X
Model space transfer modeled according to the number of function combinations
Criterion filtered by the filter coefficients corresponding to the function
Signal r_kmDigital to generate (see equation (6) below)
Filtering and this filtered reference signal r_km
And residual noise detection signal e₁ ~ E_FourAdaptive digitizer based on
Filter coefficient W in the filter processing _miLMS (Lea
st MeanSquare) file to update using the algorithm
The seating sensor 9FL
~ 9RR seating detection signal S_FL~ S_RRFilter based on
Change the weighting coefficient of the evaluation function J when updating the coefficient
The noise attenuation effect at the position where the occupant is present compared to other areas.
Control to be larger than that.

Here, the control principle of the microcomputer 26 will be described using a general formula. Now, the residual noise detection signal detected by the kth microphone 6FL to 6RR is e _k (n), and the kth microphone 6F when there is no control sound (secondary sound) from the loudspeakers 5a and 5b.
The residual noise detection signal detected by L to 6RR is e _pt (n), and the transfer function H _km between the mth loudspeakers 5a and 5b and the kth microphone 6FL to 6RR is FI.
The filter coefficient corresponding to the j-th (j = 0, 1, 2, ──I _c -1) term when expressed by the R (finite impulse response) function is C _kmj ′, and the crank angle detection signal is X ( n), the i-th (i = 0,1,2, -I _F -1) coefficient of the adaptive digital filter which inputs the crank angle detection signal X (n) and drives the m-th loudspeakers 5a and 5b. To W _mi
Then, the following equation (1) is established.

[0016] Here, the terms with (n) are all sample values at the sampling time n, and K is the microphone 6F.
L to 6RR (4 in this embodiment), M is the number of loudspeakers 5a and 5b (2 in this embodiment), and I _C is F
The number of taps (filter order) of the filter coefficient C _km ′ represented by the IR digital filter, and I _F are the number of taps (filter order) of the filter coefficient W _mi represented by the adaptive digital filter.

[{ΣW _mi · X (nj
-i)} "(= the section y _m) represents the output when the adaptive digital filter crank angle detection signal X," Σ
The term “C _{km j} · {ΣW _mi · X (nji)}” means that the signal energy input to the mth loudspeakers 5a and 5b is output as acoustic energy from these loudspeakers 5a and 5b, and the spatial transfer function in the vehicle interior is calculated. The signal when reaching the k-th microphone 6FL to 6RR via C _km ,
Furthermore, the entire second term on the right side of “ΣΣC _kmj · {ΣW _mi · X (nji)}” is the kth microphone 6FL to 6R.
Since the arrival signals to R are added up for all the speakers, the sum of the secondary sounds that reach the k-th microphone 6FL to 6RR is shown.

Next, the evaluation function J is set as in the following equation (2). Then, in this embodiment, the LMS algorithm is adopted,
The filter coefficient W _mi that minimizes the evaluation function J is obtained, and each filter coefficient W _mi of the adaptive digital filter process 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.
The gradient ∂J / ∂W _mi of the mean squared error is calculated using _mi (n), multiplied by α to obtain the (n + 1) th value W _mi (n + 1), and the value of the evaluation function J is reduced. To perform the operation.

The calculation formula for this gradient ∂J / ∂W _mi is And from the above equation (1), Therefore, Where the right side of equation (4) is Then, the gradient of the evaluation function with respect to the filter coefficient ∂J /
∂W _mi is Can be expressed as

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

In this way, the filter coefficient W _mi (n + 1) in the adaptive digital filter processing is calculated by the microphone 6
Residual noise detection signal e ₁ (n) output from FL to 6RR
e ₄ (n) and the crank angle detection signal X (n) from the crank angle sensor 7 are sequentially updated according to the LMS algorithm to input the residual noise detection signal e ₁ (n)
Drive signals y ₁ (n) and y ₂ (n) that minimize e ₄ (n) to e ₄ (n) are formed, and these are supplied to the loudspeakers 5 a and 5 b, and the control sound output from them produces the vehicle interior 2. The noise inside is canceled out.

Next, the operation of the above embodiment will be described with reference to the flowchart of FIG. 6 showing the processing procedure of the microcomputer 26. In the entire system, when the key switch is turned on, the power is turned on and the microcomputer 26 executes the timer interrupt process shown in FIG. 6 every predetermined time (for example, 1 msec). First, in step S1, the seating detection signals S _{FL to} S _RR of the seating sensors 9FL to 9RR are read, and then the process proceeds to step S2 to determine whether or not the seating detection signal S _FL is in the on state, and this is the on state. If so, the process proceeds to step S3 and the weighting coefficient a of the evaluation function described later is set to "1", and then step S5.
If it is in the off state, the process proceeds to step S4 to set the weighting coefficient a to "0", and then to step S5.
Move to.

In step S5, it is determined whether or not the seating detection signal S _FR is in the on state, and if it is in the on state, the process proceeds to step S6 and the weighting coefficient b of the evaluation function described later is set to "1". Then, the process proceeds to step S8, and when it is in the off state, the process proceeds to step S7 to set the weighting coefficient b to "0" and then proceeds to step S8.

In step S8, it is determined whether or not the seating detection signal S _RL is in the on state, and if it is in the on state, the process proceeds to step S9 and the weighting coefficient c of the evaluation function described later is set to "1". Then, the process proceeds to step S11, and when 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 S _RR is in the on state, and if it is in the on state, the process proceeds to step S12 and the weighting coefficient c of the evaluation function described later is set to "1". After that, the process proceeds to step S14, and if it is in the off state, the process proceeds to step S13 to set the weighting coefficient d to "0" and then to step S1.
Go to 4.

In step S14, the residual noise detection signal e
_{1 to} e ₄ and the reference signal X (n) are read, and then the process proceeds to step S15 to perform the calculation of the following equation (9) to evaluate the evaluation function J.
To calculate. J = ae ₁ (n) ² + be ₂ (n) ² + ce ₃ (n) ² + de ₄ (n) ² (9) where a to d are “1” or “0” as described above. Is a weighting coefficient set to ".

Then, the process proceeds to step S16, in which
Digital filter processing corresponding to Eq. (6) is applied to
Filtered reference signal r_kmAnd then step
The filtered reference signal calculated in S17.
Issue r_kmAnd residual noise detection signal e ₁~ E₃And based on the above
Filter by updating the filter coefficient according to Eq. (8).
Coefficient W_miCalculate (n + 1), then move to step S18
Then, the equation (7) is calculated to obtain the filter coefficient W of the evaluation function J.
The gradient ∂J / ∂W with respect to is less than or equal to a preset threshold ΔJ
It is determined whether or not, and when ∂J / ∂W> ΔJ,
Is the target filter coefficient W that minimizes the evaluation function J_optReached
If it is determined that it has not been performed, the process returns to step S14,
When ∂J / ∂W ≦ ΔJ, the evaluation function J is the minimum.
Target filter coefficient W_optIt is judged that it has come close enough to
Then, the process proceeds to step S19.

In this step S19, step S18
The adaptive digital filter process is executed based on the filter coefficient W _mi (n + 1) calculated in
The drive signals y _{1 and} y ₂ for b are calculated, and then the process proceeds to step S20 to output the calculated drive signals y _{1 and} y ₂ to the D / A conversion circuits 27a and 27b, and then the timer interrupt processing is ended. To return to the specified main program.

Here, the processing of steps S1 to S13 of FIG. 6 corresponds to the evaluation function weight changing means, and steps S14 to S14.
The process of step S20 corresponds to the control means. Therefore, assuming that the key switch is on and the engine 3 is stopped in the idling state, noise corresponding to the rotation speed N of the engine 3 is transmitted to the vehicle interior 2. At this time, there are four passengers in the vehicle, and each seat 8FL to 8FL.
Assuming that all the seating detection signals S _{FL to} S _RR of the seating sensors 9FL to 9RR are seated in the RR and the seating detection signals S _{FL to} S _RR are in the ON state, when the processing of FIG.
The weighting factors a to d are set to "1" in the process of S13.

Therefore, the evaluation function J calculated according to the equation (9) in step S15 is the seats 8FL to 8R.
It 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, and
Based on these residual noise detection signals e _{1 to} e ₄ , the filter coefficients in the adaptive digital filter processing are sequentially updated according to the LMS algorithm, and each residual noise detection signal e ₁
Drive signals y _{1 and} y ₂ for the loudspeakers 5a and 5b are calculated so that the evaluation function J with which e ₄ is approximately the same evaluation weight is minimized, and this is calculated as the D / A conversion circuits 27a and 2a.
It is supplied to the loudspeakers 5a and 5b via 7b.
Therefore, the drive signals y _1, from the loudspeakers 5 a and 5 b are
A control sound corresponding to y ₂ is emitted and interferes with noise so that the residual noise detection signals e _{1 to} e ₄ of the microphones 6FL to 6RR are minimized, that is, noise is attenuated at all seats 8FL to 8RR positions. The effect is demonstrated.

However, when the occupant is seated only in the driver's seat 8FR, the seating sensor 9 in the driver's seat 8FR is used.
Only the seating detection signal S _{FR of the FR} is turned on, and the seating sensors 9FL, 8FL, 8RL, 8RR of the other seats
The seating detection signals S _FL, S _{RL, and} S _RR of 9 _{RL and 9 RR} are kept off. Therefore, when the process of FIG. 6 is executed, the process proceeds from step S2 to step S4 to set the weighting coefficient a to "0", and then from step S5 to step S6 to set the weighting 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 above the driver seat 8FR. Only the residual noise detection signal e ₂ (n) of the microphone 6FR is set.

Therefore, the seat 8F other than the driver seat 8FR
Even if the noise at L, 8RL, 8RR becomes large and the residual noise detection signals e _1, e _3, e ₄ of the corresponding microphones 6FL, 6RL, 6RR become large values,
These do not affect the evaluation function J. Therefore, 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 it becomes possible to concentrate the noise suppression energy only on the driver's seat 8FR, and the noise damping effect in the driver's seat 8FR. Can be made larger to form a comfortable acoustic space.

Similarly, when an 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 squares of the residual noise detection signals e ₁ and e ₂ of the corresponding microphones 6FR and 6FL. By setting, the large noise damping effect is preferentially exerted on the front seats 8FL and 8FR, and the noise damping effect is reduced on the remaining rear seats 8RL and 8RR.

Although the seat sensors 9FL to 9RR are used as the occupant detecting means in the first embodiment, the present invention is not limited to this.
It is also possible to apply passenger detection means such as an infrared sensor,
Alternatively, when the door close to the microphone is opened, it may be determined that the passenger 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 weighting factors a to d in the first embodiment are changed only when the vehicle starts traveling. That is, as shown in FIG. 7, step S0 is added before step S1 in FIG. 6 to determine whether or not the vehicle has started running from the stopped state. In step S0, the vehicle is stopped or the vehicle is running. If it is, the process directly goes to the step S14, except that the process goes to the step S1 only when the vehicle starts traveling from the stopped state.
Processing similar to that in FIG. 6 in the embodiment is executed. It should be noted that the weighting factors a to d are all set to, for example, "1" by the initialization at the start of execution of the predetermined main program.

According to the second embodiment, when the vehicle is stopped and the key switch is turned on, the weighting factors a to d are all initialized to "1" by a predetermined main program. When continuing, the process proceeds from step S0 to step S14, so that the residual noise detection signals e ₁ to e of all the microphones 6FL to 6RR are
Noise suppression control is performed using the sum of squares of e ₄ as the evaluation function J,
When the vehicle starts traveling from the stopped state, step S0
By shifting from step S1 to step S1, it is possible to exert an effective noise suppressing effect according to the sitting position of the occupant.

Therefore, when the vehicle is stopped,
Changes in occupants are expected due to passengers getting on and off.
The seating detection signal S of the seating sensors 9FL to 9RR_FL
~ S _RRFluctuates, the evaluation function J also fluctuates and
When it becomes a generation factor and cannot effectively exhibit the noise suppression effect
May occur, but the weighting factors a to d are changed while the vehicle is stopped.
Prevent fluctuation of the evaluation function J by prohibiting
More accurate noise suppression control can be performed. Similarly, car
Changing the weighting factors a to d is prohibited even when both are running
If you lift your hip from the seated condition of the occupant,
The seating detection signals S of the seating sensors 9FL to 9RR_FL~
S_RREven if is temporarily changed, the fluctuation of the evaluation function J
It is possible to prevent and maintain a good acoustic space.

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 is made to follow in accordance with the head movement of the occupant when the tilting angle of the reclining seat of the vehicle is changed. That is, as shown in FIG. 8, the seat cushions SC of the reclining seats 31F and 31R of the vehicle.
And a reclining mechanism 3 provided between the seat back SB
2 is provided with tilt angle sensors 33F and 33R that detect the tilt angle θ of the seat back SB, and a pair of upper and lower microphones 34F _{U and} 34F are provided on the rear side of the seat back SB _{, respectively.
L} and 34R _U, 34R _L are provided, and each tilt angle sensor 33
The tilt angle detection values θ _{F and} θ _{R of} F and 33R are determined by the controller 15.
Has been entered in.

Then, the controller 15 executes the noise suppressing process shown in FIG. That is, step S21
The tilt angle detection values θ _F, θ _R of the tilt angle sensors 33F, 33R
Is read, and then the process proceeds to step S22, in which the tilt angle detection value θ _F, which is set in advance based on the tilt angle detection values θ _F, θ _{R ,}
The weighting factors a _{U and} b _U are calculated with reference to the map shown in FIG. 10 which shows the relationship between θ _R and the weighting factors a _{U and} b _U with respect to the residual noise detection values e _1U and e _2U of the microphones 34F _{U and} 34R _U. Then, in step S23, the residual noise detection values e _1L and e _{2L of the} microphones 34F _{L and} 34R _L are calculated from the calculated weighting factors a _{U and} b _U according to the following formulas (10) and (11).
Calculate the weighting factors a _L, b _L for.

A _L = 1−a _u (10) b _L = 1−b _U (11) Then, the process proceeds to step S24 and step S in FIG.
As with 14, each microphone 34F _U, 34F _L and 3
4R _U, 34R _L residual noise detection value e _1U, e _1L, e _2U, e
_2L and the crank angle detection value X of the crank angle sensor 7 are read, then the process proceeds to step S25, and the evaluation function is calculated according to the following equation (12) based on the calculated weighting factors a _U, a _L, b _{U, and} b _L. Calculate J.

J = a _U e _1U ² + a _L e _1L ² + b _U e _1U ² + b _L e _1L ² (12) Thereafter, the same processing as steps S16 to S20 of FIG. 6 is performed at steps S26 to S30. Done in. According to this third embodiment, for example, the seat back SB is
At a tilt angle θ _{0 that} makes the state close to the vertical state, as shown in FIG. 10, the weighting factors a _U, b _U corresponding to the upper microphones 34F _U, 34R _U are set to “1”, and conversely the lower side. Weighting coefficient a corresponding to the microphones 34F _{L and} 34R _{L
Since L and} b _L are set to “0”, the evaluation function J calculated in step S25 is e _1U ² + e _1U ² , and the residual noise detection of the microphones 34F _{U and} 34R _U closest to the head of the seated person is detected. Since only the signals e _1U and e _2U are to be controlled, the position above the seat back SB where the occupant's head is present is set as the noise attenuation target space.

From this state, when the reclining mechanism 32 is operated 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 becomes smaller, and conversely the lower microphone 34F
By gradually increasing the weighting factors a _{L and} b _L for the residual noise detection signals e _{1L and} e _2L of _{L and} 34R _L , the noise attenuation target space can be tracked as the passenger head moves due to the tilt of the seat back SB. It is possible to gradually move downward and maintain a good acoustic space.

Next, a fourth embodiment of the present invention will be described with reference to FIGS.
12 will be described. This fourth embodiment is a boxcar.
-For example, when the seat is rotatable in a horizontal plane
Follow the movement of the seated person's head position as the seat rotates.
Then, the noise attenuation space is moved.
That is, as shown in FIG.
Seat 4 in the middle of seats 41F, 41M, 41R in a row
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,
For the front and rear fixed seats 41F and 41R,
Microphone at the ceiling position facing the SB from above.
43F and 43R are provided, and the seat 41M in the middle is
As for the seat back SB, the seat back SB faces 180 degrees on the front-back direction line.
Above the seat back SB when in the rotating position
Microphone 43M at the ceiling position facing toward_F,43M
_RIs installed, and the rotation angle detection value δ of the rotation angle sensor 42 and the
Icrophone 43F, 43M _F,43M_R,43R residual noise
Sound detection value e_1,e_2F,e_2RAnd e₃To the controller 15
Is entered.

Then, the controller 15 executes the 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 from the set weighting factor b _F to the weighting factor b _R (= 1−
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
Perform the same processing as.

J = e ₁ ² + b _F e _2F ² + b _R e _2R ² + e ₃ ² (13) According to the fourth embodiment, the seat 41M in the middle portion has the seat back SB as the rear side. In the forward seated state, the rotation angle detection value δ of the rotation angle sensor 42 becomes 0 degrees,
Therefore, the weighting coefficient b _R for the residual noise detection signal e _2R of the rear microphone 43M _R calculated in step S32 becomes “1”, and conversely the weight for the residual noise detection signal e _2F of the front microphone 43M _F. Coefficient b _F
Is 0, the evaluation function J is e ₁ ² + e _2R ² + e ₃ ²
Therefore, for the seat 41M in the middle part, only the microphone 43M _R on the rear side affects the evaluation function J, and for the seat 41M, the position of the microphone 43M _R is the noise attenuation target space. , Seat 41M
It is possible to form a noise attenuation target space corresponding to the head of the seated person.

When the seat 41M is gradually rotated clockwise or counterclockwise by 180 degrees from this state, the weighting coefficient b _R is decreased in accordance with the increase of the rotation angle δ, and the weighting coefficient b is increased.
_{Since F} increases, the noise attenuation target space gradually moves forward following the movement of the passenger's 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, but the present invention is not limited to this, and the engine speed is equal to or lower than the predetermined speed. When, there is no seated person, that is, when the seating detection signals S _{FL to} S _{RR of the} seating sensors 9FL to 9RR are all off, and the door is open, the noise suppression control process may be stopped. In such an absence of an occupant, the occupant's ear position is expected to be in a position different from the normal noise attenuation target space as when cleaning the passenger compartment floor panel, etc. Can be prevented.

In each of the above embodiments, the case where the loudspeaker is applied as the control sound source has been described. However, the present invention is not limited to this, and a vibrator may be applied, and a microphone for detecting residual noise is also applicable. Alternatively, an acceleration vibration sensor may be applied. Furthermore, the number of installed loudspeakers and microphones is not limited to the above-mentioned embodiments, and may be any number of 2 or more.

Furthermore, in each of the above embodiments, the case where engine noise is suppressed has been described, but the present invention is not limited to this, and vibration input from the road surface is detected in the wheels to suppress road noise and to reduce window noise. The vibration of the glass can be detected to suppress the wind noise, and the composite sound of these can also be suppressed. Further, in each of the above-described embodiments, the case where the microcomputer 26 performs the adaptive digital filter processing and the digital filter processing of the filter coefficient according 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
An algorithm other than the MS algorithm may be applied and updated.

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

[0050]

As described above, according to the active noise control device of the first aspect, the occupant detecting means detects the presence of the occupant, and the evaluation function weight changing means responds to the occupant's absent position. Since the weight for the evaluation function of the residual noise detection signal is changed to be small compared to other positions, when the occupant is small, compared to the case where the noise damping effect is exerted on the entire predetermined space, The noise damping energy can be enhanced by concentrating the noise damping energy at the position where the occupant is present, and a comfortable acoustic space can be formed.

According to the active noise control device of the second aspect, the weight change by the evaluation function weight changing means is limited to only when the vehicle starts to travel. Therefore, the vehicle is in a stopped state or a running state. Thus, it is possible to prevent the fluctuation of the evaluation function due to the movement of the occupant and to exert a good noise suppressing effect. Further, according to the active noise control device of the third aspect, when the seat is tiltable, the residual noise detection signals of the pair of upper and lower residual noise detecting means arranged according to the tilted state. Since the weight given to the evaluation function of is changed, it is possible to move the noise attenuation target space by following the vertical movement of the occupant's head due to tilting of the seat back, and form a comfortable acoustic space. The effect that can be obtained is obtained.

Further, according to the active type noise control device of the fourth aspect, when the seat is configured to be rotatable in the horizontal plane, the residual noise detection disposed in front and rear according to the rotational position thereof. Since the weight given to the evaluation function of the residual noise detection signal of the means is changed, the noise attenuation target space can be moved by following the movement of the head of the occupant in the front-back direction due to the rotation of the seat, which is comfortable. An effect that an acoustic space can be formed is obtained.

[Brief description of 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 showing an example of a controller.

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

FIG. 7 is a flow chart showing an example of a processing procedure of the microcomputer in the 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 showing an example of a processing procedure of a microcomputer in the third embodiment.

FIG. 10 is an explanatory diagram showing a map showing a relationship between a tilt angle detection value 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 showing an example of a processing procedure of a microcomputer in the fourth embodiment.

FIG. 13 is an explanatory diagram showing a map showing a relationship between a rotation angle detection value δ and a weighting coefficient b _F in the fourth embodiment.

[Explanation of symbols]

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

Claims (4)

[Claims] 1. 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 detecting means for detecting residual noise in the predetermined space, and the noise. Noise generating state detecting means for detecting the noise generating state of the source, and minimizing the sum of squares of the detected values of the residual noise detecting means as an evaluation function based on the detected values of the noise generating state detecting means and the residual noise detecting means. In the active noise control device having the control means for outputting the drive signal for driving the control sound source as described above, when the passenger detection means for detecting the occupant's boarding state and the absence of the passenger are detected by the boarding 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 detecting means near the detection point to a small value. 2. The active noise control device according to claim 1, wherein the evaluation function weight changing means is configured to change the weight only when the vehicle starts traveling. 3. 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. A detection means, a noise generation state detection means for detecting the 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. In an active noise control device provided with a control means for outputting a drive signal for driving the control sound source so as to minimize the sum of squares, a tilting state detecting means for detecting a tilting state of a seat, and the tilting state detecting means. And an evaluation function weight changing means for changing the weight given to the evaluation function of the detection values of the upper and lower residual noise detecting means in accordance with the detected value of the active noise control apparatus. 4. 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 detecting means for detecting residual noise in the predetermined space, and the noise. Noise generating state detecting means for detecting the noise generating state of the source, and minimizing the sum of squares of the detected values of the residual noise detecting means as an evaluation function based on the detected values of the noise generating state detecting means and the residual noise detecting means. In the active noise control device having the control means for outputting the drive signal for driving the control sound source, the rotational position detecting means for detecting the horizontal rotational position of the seat and the detected value of the rotational position detecting means And an evaluation function weight changing means for changing the weight given to the evaluation function of the detection value of the front and rear residual noise detecting means.