KR20190139618A - Apparatus for active noise control and method thereof - Google Patents

Abstract

An active noise control apparatus according to the present invention comprises: a noise collection unit configured to collect noise generated from a noise source; a boarding information generation unit configured to generate boarding information including a boarding position and a number of occupants in an automobile; and a control signal generation unit which receives a signal from the noise collection unit and the boarding information generation unit, analyzes the magnitude and frequency of the noise using an active noise control algorithm, and generates a control signal having an inverse phase of the noise. In this case, the control signal generation unit corrects an error of the control signal according to the change of the boarding information through a secondary path filter. The secondary path filter corrects the error of the control signal by selecting one or more of secondary path data generated in advance.

Description

Active noise control device and its method {APPARATUS FOR ACTIVE NOISE CONTROL AND METHOD THEREOF}

The present invention relates to an active noise control apparatus and method for controlling the noise, and more particularly, to an active noise control apparatus and method of the vehicle that can reduce the noise that can occur in the vehicle.

Noise reduction methods include Noise Source Control (NSC) and Active Noise Control (ANC).

Among them, active noise control technology, which is a technique of canceling noise by sound interference by generating a control signal having a reverse phase of a first noise source as a second noise source, has been variously used for reducing indoor noise of a vehicle.

However, in the conventional active noise control technology, when the listening area of the occupant changes, a phase in which the control signal generated from the speaker arrives does not become out of phase.

The prior art adjusts to a specific area (particularly around the headrest), which makes it difficult to actively respond to a situation that changes depending on the occupant's position.

Therefore, there is a need for a noise control technology that can actively respond to changes in the position of the occupant.

An embodiment of the present invention provides an active noise control apparatus and method for setting a parameter according to the position of the occupant to track the position in real time even if the occupant's position changes, and actively increase the noise reduction effect by correspondingly. It aims to provide.

However, the technical problem to be achieved by the present embodiment is not limited to the technical problem as described above, and other technical problems may exist.

As a technical means for achieving the above technical problem, the active noise control device according to the first aspect of the present invention includes a noise collecting unit for collecting the noise generated from the noise source, the number and the boarding position of the occupants in the vehicle The boarding information generating unit which generates boarding information, receives a signal from the noise collecting unit and the boarding information generating unit, analyzes the magnitude and frequency of the noise using an active noise control algorithm, and generates a control signal having the reverse phase of the noise. And a control signal output unit for outputting the control signal. In this case, the control signal generation unit corrects the error of the control signal by determining the combination of the secondary path data stored for each position of the seat based on the boarding information and applying it to the active noise control algorithm.

The boarding information generator may generate the boarding information by using image information and seat position information photographed by a camera.

The control signal generator uses an FxLMS algorithm as the active noise control algorithm to generate the control signal, and the pre-generated second path to actively change the secondary path characteristics of the FxLMS based on the boarding information. By selecting one or more of the data in combination, it can be used as the weight of the secondary path filter.

As the second path data is measured by a microphone installed at each candidate position of the listening area of the occupant, the second path data may be generated so that the control signal converges on the inverse of the noise information.

The weight of the secondary route filter may be selected according to a passenger position candidate group including a combination of the boarding information and the secondary route data generated according to the boarding information.

The control signal generator corrects the weight of the FxLMS filter in a first correction step of comparing the actual input value of the noise information with the measured value of the microphone, and in the second correction step of using the boarding information and the secondary path filter. The weight of the control signal may be corrected by a third correction step using correcting the weight of the secondary path filter and using the corrected weight of the FxLMS filter and the corrected weight of the secondary path filter.

The control signal generator uses the FxLMS filter to weight the FxLMS filter based on a difference between a k-th noise input value and a weight of the FxLMS filter and a measurement value of the k-th noise input through a microphone. A first correction step of correcting the correction may be performed.

The control signal generator selects the secondary route weight by combining one or more of the position information of the occupant included in the boarding information and the secondary route data generated according to the position information using the secondary route filter. The second position correction step may be performed to apply the occupant position candidate group to correct the weight of the secondary path filter.

The control signal generator may be configured to output an output value that is a product of an input value of a k-th random noise and a weight of the control signal, a difference between a product of a weight of the second path filter and a measured value of the k-th random noise, and the first correction. The third correction step may be performed to update the input value of the k-th random noise to the input value of the k-th noise and correct the weight of the control signal based on a filter value multiplied by the weight of the FxLMS filter.

In addition, the active noise control method according to the second aspect of the present invention comprises the steps of collecting the noise generated from the noise source; Generating boarding information including a number of passengers and a boarding position of the passenger in the vehicle; Generating a control signal having an inverse phase of the noise by using an active noise control algorithm based on the collected noise information and the boarding information, and outputting the control signal. In this case, the generating of the control signal corrects the error of the control signal by determining the combination of the secondary path data stored for each position of the seat based on the boarding information and applying it to the active noise control algorithm.

In this case, the generating of the control signal may be used as a weight of the secondary path filter by using FxLMS as an active noise control algorithm and selecting one or more of the previously generated secondary path data in combination.

The generating of the control signal may include correcting a weight of the FxLMS filter by comparing an actual input value of the noise information with a measured value of a microphone; Correcting the weight of the secondary path filter using the boarding information and the secondary path filter, and weighting the control signal based on the weight of the corrected FxLMS filter and the weight of the corrected secondary path filter. And correcting.

According to any one of the problem solving means of the present invention described above, by setting a parameter capable of active response according to the change in the position of the occupant, it is possible to correct the error of the noise control signal and to provide a more effective noise control technology to the occupant. .

1 is a view for explaining the principle of the generation of secondary route data and the setting of the passenger listening area candidate group.
2 is a block diagram of an active noise control apparatus according to an embodiment of the present invention.
3 is a diagram illustrating an active noise control algorithm applied to an active noise control device according to an embodiment of the present invention.
4 is a flowchart of an active noise control method according to an embodiment of the present invention.
5 is a flowchart illustrating a first correction step of an active noise control algorithm.
FIG. 6 is a flowchart illustrating second and third correction steps of an active noise control algorithm.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention.

Meanwhile, the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, “comprise” and / or “comprising” means that the stated components, steps, operations and / or elements are one or more of the other components, step operations and / or elements or It does not exclude the addition.

The present invention relates to an active noise control device (100) and a method thereof.

Active Noise Control (ANC) generates a control signal having a reverse phase of the first noise source as a second noise source to cancel the target noise by interference of the two noise sources.

Here, the first noise source (hereinafter referred to as noise) means a control object that is not desired by the user.

The second noise source (hereinafter referred to as a control signal) means a signal for canceling the first noise source.

However, in the conventional active noise control technology, when the passenger's listening area is changed, a phase in which a control signal generated from a speaker arrives does not become out of phase and an error occurs.

FIG. 1A is a diagram illustrating an error generation of a control signal according to a passenger's listening area change, and FIG. 1B is a view for explaining a passenger listening area candidate group setting for generating secondary route data. .

In the conventional active noise control technology, as shown in FIG. 1A, a control signal for noise generated from a noise source does not actively respond to a change in a passenger's listening area.

Therefore, as shown in (b) of FIG. 1, the passenger listening area candidate group is set, and the combination of the secondary path data stored for each seat position is determined based on the result of recognizing the occupant's position and applied to the FxLMS algorithm to determine the occupant's position. Actively respond to change

Here, the secondary path refers to a compensation path from which the control signal is generated by the active noise control algorithm to derive a comparison value, and the secondary path data is a phase of the control signal reaching the previously expected position of the passenger. Means the data generated by using the measured value to be in the reverse phase.

Hereinafter, an active noise control apparatus 100 according to an embodiment of the present invention will be described with reference to FIG. 2.

2 is a block diagram of an active noise control apparatus 100 according to an embodiment of the present invention.

As shown in FIG. 2, the active noise control device 100 includes a noise collector 110, a boarding information generator 120, a control signal generator 130, and a control signal output unit 140.

The noise collector 110 collects the noise generated by the vehicle and transmits the noise to the control signal generator 130.

Here, "noise" refers to unwanted noise that may cause inconvenience to the occupant, and corresponds to noise such as road friction noise or engine sound.

However, "noise" is not meant to be limited to road friction noise or engine sounds, and may include sounds that may be uncomfortable for the occupant.

The boarding information generator 120 generates boarding information including the number of boarding passengers and the boarding position of the boarding vehicle and transmits the boarding information to the control signal generator 130.

The control signal generator 130 generates a control signal having an inverse phase of the corresponding noise through the first correction step and the second and third correction steps of the active noise control algorithm based on the noise information and the boarding information.

The control signal output unit 140 outputs the control signal received from the control signal generator 130.

Hereinafter, an active noise control algorithm of the control signal generator 130 will be described with reference to FIG. 3. The first correction step of the active noise control algorithm is to find a weight value suitable for the FxLMS filter 202 while tracking the opposite signal of the noise coming into the microphone.

3 is a view for explaining a functional block of an active noise control algorithm according to an embodiment of the present invention.

3, first, as the noise signal x (k) is input to the Sh (z) block 201 of the FxLMS filter 202, the Sh (z) block 201 uses its state value according to Equation (1). Update.

[Equation 1]

Here x _iden (k) means the input value of the k-th noise, Shx means the state value of the Sh (z) block 201.

Subsequently, the calculated value according to Equation 2 is output using the updated state value of the Sh (z) block 201 and the weight of the FxLMS filter 202.

[Equation 2]

Here Shw means the weight of the adjusted FxLMS filter 202.

Next, the measured value of the k-th noise signal output from the P (z) block 205 and the output value according to equation (2) are compared. A subtraction equation by Equation 3 is performed.

[Equation 3]

Here, e _iden (k) means a comparison value between two output values used in the equation, and y _iden (k) means a measured value of the k-th noise signal output from the P (z) block 205.

Next, the weight Shw of the FxLMS filter 202 is corrected using the state value Shx of the Sh (z) block 201 updated by Equation 1 and the comparison value e _cont (k) calculated by Equation 3. do. The next order update by Equation 4 is made.

[Equation 4]

Where mu is the learning rate.

The second correction step of the active noise control algorithm corrects the weight Shw of the secondary path filter 206 by using the boarding information and the secondary path filter 206. The third correction step corrects the weight Cw of the control signal using the weight Shw of the FxLMS filter 202 of the first correction step and the weight Sw of the secondary path filter 206 of the second correction step.

As shown in FIG. 3, first, as the noise signal x (k) is input to the C (z) block 204, the C (z) block 204 updates its state value Cx by Equation 5.

[Equation 5]

Here, x _cont (k) means the micro-input k-th random noise value, and Cx means the state value of the C (z) block 204.

[Equation 6]

Here, Cy means an output value to which the adjusted control signal weight is applied, and Cw means a weight of the adjusted control signal.

At this time, Cy is canceled with noise while being output as a control signal, and the noise is canceled and the remaining residual noise is input again through a microphone to correct an error.

Subsequently, the state value of the C (z) block 204 of Equation 5 is updated to the first state value of the S block using Equation 7.

[Equation 7]

Here, Sx means a state value of the S (z) block 203.

Next, a combination equation is applied to the generated second route data according to the occupant position value p of the boarding information. Equation 8 according to the passenger position candidate group is performed.

[Equation 8]

Subsequently, the k-th random noise of the P (z) block 205 is measured using the state value of the S (z) block 203 updated by Equation 7 and the secondary path filter weight value according to Equation 8. Compare with the value. A subtraction equation by Equation 9 is performed.

[Equation 9]

Here, yd (k) means a measured value of the k-th random noise of the P (z) block 205, and econt (k) means a calculated value of the residual noise.

Subsequently, in the FxLMS filter 202, the input value x _cont (k) of the k-th random noise is updated to the state value of the FxLMS filter 202 by Equation 10.

[Equation 10]

Here, Shx is a state value of the FxLMS filter 202.

Subsequently, the state value of the FxLMS filter 202 is calculated and updated by Equation 11 in the FxLMS filter 202.

[Equation 11]

Here, Xhx means a state value of the FxLMS filter 202.

Next, in the C (z) block 204, the weight of the control signal is corrected by Equation 12 to update to the next order.

[Equation 12]

Here mu refers to a learning rate and Cw refers to a weight of a control signal.

On the other hand, the noise collector 110, the boarding information generator 120, the control signal generator 130 and the control signal output unit 140 of the active noise control device 100 according to an embodiment of the present invention is a memory (Not shown) and a processor (not shown) for executing a program stored in the memory.

Here, the term "memory" refers to a nonvolatile storage device and a volatile storage device that maintains stored information even when power is not supplied.

For example, the memory may be a compact flash (CF) card, a secure digital (SD) card, a memory stick, a solid-state drive (SSD), a micro SD card, or the like. Magnetic computer storage devices such as NAND flash memory, hard disk drive (HDD), and the like, optical disc drives such as CD-ROM, DVD-ROM, and the like.

For reference, the components shown in FIG. 2 according to an embodiment of the present invention may be implemented in software or hardware form such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC), and perform predetermined roles. can do.

However, 'components' are not meant to be limited to software or hardware, and each component may be configured to be in an addressable storage medium or may be configured to reproduce one or more processors.

Thus, as an example, a component may include components such as software components, object-oriented software components, class components, and task components, and processes, functions, properties, procedures, and subs. Routines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables.

Components and the functionality provided within those components may be combined into a smaller number of components or further separated into additional components.

Hereinafter, an active noise control method performed by the active noise control apparatus 100 according to an embodiment of the present invention will be described with reference to FIGS. 4 to 6.

4 is a flowchart illustrating an active noise control method of the active noise control apparatus 100 according to an embodiment of the present invention.

In the active noise control method with reference to FIG. 4, first, noise generated from a noise source is collected (S110).

Next, the boarding information including the number of passengers and the boarding position in the vehicle is generated (S120).

Subsequently, a control signal using an active noise control algorithm is generated based on the noise information of step S110 and the boarding information of step S120 (S130).

Finally, the control signal is output and the residual noise is fed back (S140).

The active noise control algorithm performed in the control signal generation step of step S130 of FIG. 4 includes a first correction step and a second and third correction steps.

5 is a flowchart illustrating a first correction step of the active noise control algorithm, and FIG. 6 is a flowchart illustrating the second and third correction steps.

As shown in FIG. 5, the first correction step of the active noise control method according to an embodiment of the present invention first updates the state value of the Sh (z) block 201 (S1301).

At this time, the actual noise input value is used as the updated state value.

Subsequently, in the Sh (z) block 201, an output obtained by applying the weight of the FxLMS filter 202 is calculated (S1302).

In this case, referring to FIG. 4, since the result value of step S1304 is reflected in step S1303, the error is corrected by feeding back the output value as an input.

Referring back to FIG. 5, the measured value of the k-th noise signal output from the p (z) block 205 is compared with the output value calculated in step S1302 (S1303).

Finally, the weight Shw of the FxLMS filter 202 is corrected using the resultant value and the current state value Shx of step S1303 (S1304).

The first correction step, which has undergone the above process, performs a process for correcting an error between an input value and a measured value of actual noise.

As shown in FIG. 6, the second and third correction steps of the active noise control method according to an embodiment of the present invention first update the state value Cx of the C (z) block 204 (S1305).

At this time, since the k-th random noise x _cont (k) is sequentially inserted into the state value of the C (z) block 204, the input value of the actual noise is input.

Next, the output obtained by applying the weight of the control signal is calculated in the C (z) block 204 (S1306).

Subsequently, the output calculated in step S1306 is updated to the state value Cx of the S (z) block 203 (S1307).

At this time, the state value Cx of the S (z) block 203 is generated as a dummy state for applying the secondary path data.

Next, the weight of the secondary path filter 206 is calculated (S1308).

On the other hand, since the detailed information applied in step S1308 has been described in Figure 3 and the equation (9), it will be omitted below.

Subsequently, the residual noise e _cont (k) is calculated by subtracting the output value Cy calculated in step S1306 from the measured value yd (k) (S1309).

Next, the k-th random noise is added to the state value Shx of the Sh (z) block 201 in order to correct an error between the input noise and the measured value of the actual noise generated as the residual noise calculated in step S1309 is again input into the microphone. Update the input value x _cont (k) (S1310).

Next, the filter value Xhx of the FxLMS filter 202 is calculated using the state value Shx of the Sh (z) block 201 updated in step S1310 and the weight Shw of the FxLMS filter 202 corrected in step S1304. It updates it (S1311).

Finally, the weight value Cw of the control signal is corrected using the filter value Xhx updated in step S1311 and the residual noise e _cont (k) calculated in step S1309 (S1312).

In the second and third correction steps, the control signal for controlling the noise is output at the same time as correcting the error between the input value and the measured value of the actual noise, and correcting the calculated residual noise. Perform the process of correcting the error.

At this time, since the weight Sw of the secondary path filter 206 corresponding to the boarding information is reflected in the weight of the noise signal for controlling the noise, it is possible to proactively respond to the change in the position of the occupant, thereby increasing the noise reduction effect. .

One embodiment of the present invention may also be embodied in the form of a computer program stored in a medium executed by a computer or a recording medium including instructions executable by the computer. Computer readable media can be any available media that can be accessed by a computer and includes both volatile and nonvolatile media, removable and non-removable media. In addition, computer readable media may include both computer storage media and communication media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Communication media typically includes computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave, or other transmission mechanism, and includes any information delivery media.

Although the methods and systems of the present invention have been described in connection with specific embodiments, some or all of their components or operations may be implemented using a computer system having a general purpose hardware architecture.

The foregoing description of the present invention is intended for illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present invention is shown by the following claims rather than the above description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

100: active noise control device 110: noise collector
120: boarding information generation unit 130: control signal generation unit
140: control signal output unit 201: Sh (z) block
202: FxLMS filter 203: S (z) block
204: C (z) block 205: P (z) block
206: secondary path filter

Claims (12)

In the active noise control device for the noise control of the vehicle,
Noise collection unit for collecting the noise generated from the noise source,
A boarding information generator for generating boarding information including a boarding position and a number of occupants in the vehicle;
A control signal generator for generating a control signal having an inverse phase of the noise by using an active noise control algorithm based on the collected noise information and the boarding information;
Including a control signal output unit for outputting the control signal,
The control signal generator is configured to correct the error of the control signal by determining the combination of the secondary path data stored for each position of the seat based on the boarding information to the active noise control algorithm. The method of claim 1,
The boarding information generation unit generates the boarding information by using image information and seat position information captured by a camera. The method of claim 1,
The control signal generator uses an FxLMS algorithm as the active noise control algorithm to generate the control signal,
Active noise control is used as a weight of the secondary path filter by selecting one or more of the secondary path data generated in advance in order to actively change the characteristics of the secondary path of the FxLMS based on the boarding information. Device. The method of claim 3, wherein
And the second path data is generated by a microphone installed at each candidate position of the listening area of the occupant so that the control signal is converged to an inverse phase of the noise information. The method of claim 3, wherein
And the second path data is generated by a microphone installed at each candidate position of the listening area of the occupant so that the control signal is converged to an inverse phase of the noise information. The method of claim 1,
The control signal generator corrects the weight of the FxLMS filter in a first correction step of comparing the actual input value of the noise information with the measured value of the microphone,
Correcting the weight of the secondary route filter in a second correction step using the boarding information and the secondary route filter,
And adjusting the weight of the control signal in a third correction step using the corrected weight of the FxLMS filter and the corrected weight of the secondary path filter. The method of claim 6,
The control signal generation unit uses the FxLMS filter to correct a weight of the FxLMS filter based on a difference between a product of a k-th noise input value and a weight of the FxLMS filter and a measured value of the k-th noise. Active noise control device to perform a correction step. The method of claim 6,
The control signal generator selects a weight of the secondary route filter by combining at least one of occupant position information included in the boarding information and the secondary route data generated according to the position information using the secondary route filter. and,
The selection of the passenger position candidate group is applied to the active noise control device for performing a second correction step for correcting the weight of the secondary path filter. The method of claim 6,
The control signal generator may include a difference between an output value, which is a product of an input value of a k-th random noise, a weight of the control signal, a weight of the second path filter, and a measurement value of the k-th random noise,
And performing a third correction step of updating the k-th noise value of the FxLMS filter to the k-th random noise value and correcting the weight of the control signal based on a filter value multiplied by the weight of the FxLMS filter. Device. Collecting noise generated from the noise source;
Generating boarding information including a number of passengers and a boarding position of the passenger in the vehicle;
Generating a control signal having an inverse phase of the noise using an active noise control algorithm based on the collected noise information and the boarding information;
Outputting the control signal;
In the generating of the control signal, the active noise control corrects the error of the control signal by determining a combination of secondary path data stored for each seat position based on the boarding information and applying the active signal to the active noise control algorithm. Way. The method of claim 10,
Generating the control signal using FxLMS as an active noise control algorithm,
Active noise control method using as a weight of the secondary path filter by selecting a combination of one or more of the pre-generated secondary path data. The method of claim 10,
Generating the control signal,
Correcting the weight of the FxLMS filter by comparing the actual input value of the noise information with the measured value of the microphone;
Correcting a weight of the secondary route filter using the boarding information and the secondary route filter; and
And correcting a weight of the control signal based on the weight of the corrected FxLMS filter and the weight of the corrected second path filter.

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