KR102651525B1 - Apparatus for active noise control and method thereof - Google Patents

Abstract

The active noise control device according to the present invention includes a noise collection unit that collects noise generated from a noise source, a boarding information generation unit that generates boarding information including the number of passengers on board the vehicle and the boarding location, and the noise collection unit. It includes a control signal generator that receives a signal from the boarding information generator, analyzes the size and frequency of the noise using an active noise control algorithm, and generates a control signal with an inverse phase of the noise. At this time, the control signal generator corrects the error of the control signal according to the change in the boarding information through a secondary path filter, and the secondary path filter selects by combining one or more of the secondary path data generated in advance. Correct the error of the control signal.

Description

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

The present invention relates to an active noise control device and method for noise control, and more specifically, to an active noise control device and method for a vehicle that can reduce noise that may be generated in a vehicle.

Methods for reducing noise include noise source control (NSC) and active noise control (ANC).

Among them, active noise control technology, which is a technology that cancels noise by sound interference by generating a control signal with an inverse phase of the first noise source to the second noise source, is being used in various ways to reduce interior noise of vehicles.

However, the conventional active noise control technology has a problem in that when the passenger's hearing area changes, the phase in which the control signal from the speaker arrives is not out of phase.

Conventional technology adjusts to specific areas (particularly around the headrest), but this makes it difficult to actively respond to situations that change depending on the occupant's position.

Therefore, noise control technology that can actively respond to changes in the occupant's position is needed.

An embodiment of the present invention provides an active noise control device and method that can increase the noise reduction effect by setting parameters according to the location of the occupant, tracking the location in real time even if the location of the occupant changes, and actively responding to it. The purpose is to provide

However, the technical challenge that this embodiment aims to achieve is not limited to the technical challenges described above, and other technical challenges may exist.

As a technical means for achieving the above-described technical problem, the active noise control device according to the first aspect of the present invention includes a noise collection unit that collects noise generated from a noise source, the number of passengers riding in the vehicle, and the riding position. A boarding information generation unit that generates boarding information receives signals from the noise collection unit and the boarding information generation unit, analyzes the size and frequency of the noise using an active noise control algorithm, and generates a control signal with an inverse phase of the noise. It includes a control signal generator that generates a control signal and a control signal output portion that outputs the control signal. At this time, the control signal generator corrects the error of the control signal by determining a combination of secondary path data stored for each seat location based on the boarding information and applying it to the active noise control algorithm.

The boarding information generator may generate the boarding information using image information captured through a camera and seat position information.

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

As the secondary path data is measured through a microphone installed at each candidate location of the passenger's hearing area, the control signal may be generated to converge to the anti-phase of the noise information.

The weight of the secondary path filter may be selected according to a candidate location of the passenger consisting of a combination of the boarding information and the secondary path 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 and the measured value of the microphone, and performs a second correction step using the boarding information and the secondary path filter. The weight of the secondary path filter can be corrected, and the weight of the control signal can be corrected in a third correction step 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 calculate the weight of the FxLMS filter based on the difference between the product of the input value of the kth noise and the weight of the FxLMS filter and the measured value of the kth noise input through the microphone. A first correction step may be performed to correct .

The control signal generator selects the secondary path weight by combining one or more of the secondary path data generated according to the location information and the location information of the passenger included in the boarding information using the secondary path filter, and , the passenger location candidate group may be applied to the selection to perform a second correction step of correcting the weight of the secondary path filter.

The control signal generator generates an output value that is the product of the input value of the k-th random noise and the weight of the control signal, the difference between the product of the weight of the secondary path filter and the measured value of the k-th random noise, and the first correction A third correction step may be performed in which the weight of the control signal is corrected based on the filter value multiplied by the weight of the FxLMS filter by updating the input value of the k-th random noise to the input value of the k-th noise in the step.

In addition, the active noise control method according to the second aspect of the present invention includes collecting noise generated from a noise source; Generating boarding information including the number of passengers in the vehicle and the boarding location; It includes 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, and outputting the control signal. At this time, in the step of generating the control signal, the error in the control signal is corrected by determining a combination of secondary path data stored for each seat location based on the boarding information and applying it to the active noise control algorithm.

At this time, the step of generating the control signal uses FxLMS as an active noise control algorithm, and can be used as a weight for the secondary path filter by combining and selecting one or more of the secondary path data generated in advance.

Generating the control signal includes comparing an actual input value of the noise information and a measured value of a microphone to correct the weight of the FxLMS filter; correcting the weight of the secondary path filter using the boarding information and the secondary path filter, and adjusting the weight of the control signal based on the weight of the corrected FxLMS filter and the weight of the corrected secondary path filter. It may include a correction step.

According to one of the means for solving the problems of the present invention described above, by setting parameters that can actively respond to changes in the occupant's position, errors in the noise control signal can be corrected and more effective noise control technology can be provided to the occupants. .

Figure 1 is a diagram for explaining the principle of generating secondary path data and setting the candidate listening area for the occupants.
Figure 2 is a block diagram of an active noise control device according to an embodiment of the present invention.
Figure 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.
Figure 4 is a flowchart of an active noise control method according to an embodiment of the present invention.
Figure 5 is a flowchart for explaining the first correction step of the active noise control algorithm.
Figure 6 is a flowchart for explaining the second and third correction steps of the active noise control algorithm.

Below, with reference to the attached drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts unrelated to the description are omitted.

Meanwhile, the terms used in this specification are for describing embodiments and are not intended to limit the present invention. As used herein, singular forms also include plural forms, unless specifically stated otherwise in the context. As used in the specification, “comprise” and/or “comprising” means that a referenced element, step, operation and/or element is dependent on the presence or absence of one or more other elements, steps, operations and/or elements. Addition is not ruled out.

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

Active Noise Control (ANC) is a technology that generates a control signal with the opposite phase of the first noise source to the second noise source and cancels out the target noise by interference between the two noise sources.

Here, the first noise source (hereinafter referred to as noise) refers to a control target that the user does not want.

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

However, the conventional active noise control technology has a problem in that when the passenger's listening area changes, the phase in which the control signal from the speaker arrives is not in anti-phase and an error occurs.

Figure 1(a) is a diagram showing the occurrence of errors in control signals according to changes in the passenger's hearing area, and Figure 1(b) is a diagram illustrating the setting of candidate listening areas for the occupants for generating secondary path data. .

In the case of existing active noise control technology, there is a difficulty in that the control signal for noise generated from the noise source does not actively respond to changes in the passenger's hearing area, as shown in Figure 1 (a).

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

Here, the secondary path refers to the compensation path from when the control signal is generated in the active noise control algorithm to deriving the comparison value, and the secondary path data refers to the phase of the control signal reaching the previously expected position of the occupant. This refers to data generated using measurements that cause this to be out of phase.

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

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

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

The noise collection unit 110 collects noise generated from the vehicle and transmits it to the control signal generator 130.

Here, “noise” refers to unwanted noise that may cause discomfort to passengers, and includes noise such as road friction or engine noise.

However, “noise” is not limited to road friction or engine sounds, and may include sounds that may be unpleasant to passengers.

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

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

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

Hereinafter, the 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 an operation to find a weight value suitable for the FxLMS filter 202 while tracking the opposite signal of the noise flowing into the microphone.

Figure 3 is a diagram for explaining functional blocks of an active noise control algorithm according to an embodiment of the present invention.

Referring to Figure 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 determines its state value according to Equation 1. Update.

[Equation 1]

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

Next, 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 kth noise signal output from the P(z) block 205 is compared with the output value according to Equation 2. The subtraction equation according to Equation 3 is performed.

[Equation 3]

Here, e _iden (k) refers to the comparison value of the two output values used in the equation, and y _iden (k) refers to the measured value of the kth 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 is performed according to Equation 4.

[Equation 4]

Here mu refers to the learning cycle (learning rate).

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

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

[Equation 5]

Here, x _cont (k) means the kth random noise value input into the microphone, and Cx means the state value of the C(z) block 204.

[Equation 6]

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

At this time, Cy is output as a control signal and is canceled out with the noise, and the remaining noise after canceling out the noise is input again through the microphone to correct the error.

Next, 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 the state value of the S(z) block 203.

Next, a combination equation is calculated by applying the secondary path data generated according to the passenger position value p of the boarding information. Equation 8 is performed according to the candidate location of the occupant.

[Equation 8]

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

[Equation 9]

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

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

[Equation 10]

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

Next, the state value of the FxLMS filter 202 is calculated and updated according to Equation 11 in the FxLMS filter 202.

[Equation 11]

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

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

[Equation 12]

Here, mu means the learning cycle (learning rate), and Cw means the weight of the control signal.

Meanwhile, the noise collection unit 110, the boarding information generation unit 120, the control signal generation unit 130, and the control signal output unit 140 of the active noise control device 100 according to an embodiment of the present invention are memory. (not shown) and a processor (not shown) that executes the program stored in the memory.

Here, memory is a general term for non-volatile storage devices and volatile storage devices that continue to retain stored information even when power is not supplied.

For example, memory can be found in compact flash (CF) cards, secure digital (SD) cards, memory sticks, solid-state drives (SSD), and micro SD cards. It may include magnetic computer storage devices such as NAND flash memory and hard disk drives (HDD), and optical disc drives such as CD-ROM and DVD-ROM.

For reference, the components shown in FIG. 2 according to an embodiment of the present invention may be implemented in the form of software or hardware such as FPGA (Field Programmable Gate Array) or ASIC (Application Specific Integrated Circuit), and perform certain roles. can do.

However, 'components' are not limited to software or hardware, and each component may be configured to reside on an addressable storage medium or may be configured to run on 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, processes, functions, properties, procedures, and sub-processes. Includes routines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables.

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

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

Figure 4 is a flowchart showing an active noise control method of the active noise control device 100 according to an embodiment of the present invention.

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

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

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

Finally, a 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 second and third correction steps.

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

As shown in Figure 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 input value of the actual noise is used as the updated status value.

Next, the Sh(z) block 201 calculates the weighted output of the FxLMS filter 202 (S1302).

At this time, referring to FIG. 4, the result value of step S1304 is reflected in step S1303, so the output value is fed back to the input to correct the error.

Referring again to FIG. 5, the measured value of the kth 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 result value of step S1303 and the current state value Shx (S1304).

The first correction step, which has gone through the above process, performs a process to correct the error between the input value of the actual noise and the measured value.

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, the kth random noise x _cont (k) value is sequentially inserted into the state value of the C(z) block 204, so the input value of the actual noise is input.

Next, the C(z) block 204 calculates the weighted output of the control signal (S1306).

Next, 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 created as a dummy state for applying secondary path data.

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

Meanwhile, since the specific details applied in step S1308 have been described in FIG. 3 and Equation 9 above, they will be omitted hereinafter.

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

Next, calculate the filter value This is updated (S1311).

Finally, the weight 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).

The second and third correction steps through the above process correct the error between the input value of the actual noise and the measured value, output control noise to control the noise, and correct the error of the calculated residual noise to produce a control signal. Perform the process of correcting the error.

At this time, the weight of the noise signal for controlling noise reflects the weight Sw of the secondary path filter 206 corresponding to the boarding information, thereby enabling active response to changes in the passenger's position, thereby increasing the noise reduction effect. .

An embodiment of the present invention may also be implemented in the form of a computer program stored on a medium executed by a computer or a recording medium containing instructions executable by a computer. Computer-readable media can be any available media that can be accessed by a computer and includes both volatile and non-volatile media, removable and non-removable media. Additionally, computer-readable media may include both computer storage media and communication media. Computer storage media includes both volatile and non-volatile, 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 medium.

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

The description of the present invention described above is for illustrative purposes, and those skilled in the art will understand that the present invention can be easily modified into other specific forms without changing the technical idea or essential features of the present invention. will be. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive. For example, each component described as unitary may be implemented in a distributed manner, and similarly, components described as distributed may also be implemented in a combined form.

The scope of the present invention is indicated by the claims described below rather than the detailed description above, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention. do.

100: active noise control device 110: noise collection unit
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 an active noise control device for controlling noise in a vehicle,
A noise collection unit that collects noise generated from the noise source,
A boarding information generator that generates boarding information including the number of passengers on board the vehicle and the boarding location;
A control signal generator that generates a control signal with an inverse phase of the noise using an active noise control algorithm based on the collected noise information and the boarding information, and
It includes a control signal output unit that outputs the control signal,
The control signal generator,
In the first correction step of comparing the actual input value of the noise information and the measured value of the microphone, the weight of the FxLMS filter of the active noise control algorithm is corrected,
In a second correction step using the boarding information and the secondary path filter, the weight of the secondary path filter is corrected,
An active noise control device that corrects the weight of the control signal in a third correction step using the weight of the corrected FxLMS filter and the weight of the corrected secondary path filter. According to clause 1,
The boarding information generator is an active noise control device that generates the boarding information using image information captured through a camera and seat position information. According to clause 1,
The control signal generator uses the FxLMS algorithm as the active noise control algorithm to generate the control signal,
Active noise control is used as a weight for a secondary path filter by combining and selecting one or more of the secondary path data generated in advance to actively change the characteristics of the secondary path of the FxLMS based on the boarding information. Device. According to clause 3,
As the secondary path data is measured through a microphone installed at each candidate location of the passenger's listening area, the control signal is generated to converge to the anti-phase of the noise information. delete delete According to clause 1,
The control signal generator uses the FxLMS filter to correct the weight of the FxLMS filter based on the difference between the product of the input value of the kth noise and the weight of the FxLMS filter and the measured value of the kth noise. An active noise control device that performs a correction step. According to clause 1,
The control signal generator uses the secondary path filter to select a weight of the secondary path filter by combining the passenger location information included in the boarding information and one or more of the secondary path data generated according to the location information. do,
The active noise control device performs a second correction step of correcting the weight of the secondary path filter by applying the occupant location candidate group to the selection.
delete Collecting noise generated from a noise source;
Generating boarding information including the number of passengers in the vehicle and the boarding location;
Generating a control signal with an inverse phase of the noise using an active noise control algorithm based on the collected noise information and the boarding information;
Including outputting the control signal,
The step of generating the control signal is,
Comparing the actual input value of the noise information and the measured value of the microphone to correct the weight of the FxLMS filter;
Correcting the weight of the secondary route filter using the boarding information and the secondary route filter; and
Active noise control method comprising correcting the weight of the control signal based on the weight of the corrected FxLMS filter and the weight of the corrected secondary path filter. According to clause 10,
The step of generating the control signal uses FxLMS as an active noise control algorithm,
An active noise control method that selects one or more of the pre-generated secondary path data in combination and uses them as weights for the secondary path filter. delete

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