KR102535449B1 - Device and unit for active cancellation of acoustic reflection - Google Patents

Abstract

The present invention relates to a device for the active cancellation of acoustic reflection, comprising: a sensor unit for detecting an incident sound (p^+); and a transmission unit spaced apart from the sensor unit by d and canceling a radiated sound (p^-), wherein the sensor unit is formed as a single layer, and the radiated sound (p^-) is composed of the sum of an output sound (p_t) output from the transmission unit, and a reflected sound (p_r) generated by reflecting the incident sound (p^+) from the transmission part, and the sensor unit outputs the output sound (p_t) so that the radiated sound (p^-) can be 0. Therefore, provided is a device for the active cancellation of acoustic reflection, which can respond to various acoustic frequency domains.

Description

Active reflection sound shielding unit and device {DEVICE AND UNIT FOR ACTIVE CANCELLATION OF ACOUSTIC REFLECTION}

The following description relates to an active reflective sound shielding unit and device.

A conventional sound shielding tile is composed of a sensor unit and a sound generating device, and is implemented in such a way that the sound generating device inversely excites the sound received by the sensor unit to remove the reflected sound. This method requires that the sound generator units be placed over the entire area of the submersible. In addition, since a single sensor cannot distinguish incident sound from reflected sound, a feedback system was configured to separate the incident sound from the reflected sound through an additional external receiving device and finally control the reflected sound. In addition, in the conventional acoustic reflection control device, two sensors formed of two layers are located on the front side of a canceling actuator. Each sensor has the form of a thin film that transmits sound, and the controller (Electric Feedback Controller) controls the reflected sound of the incident sound (P+) through the processing of the sound received through the two sensor layers. serves as input.

That is, the conventional sound reflection control device implements the same function by miniaturizing the size of tile-type sound generators or sensors while maintaining a certain distance between them, and in this case, the miniaturized unit unit is It is composed of a single layer sound generator. According to this configuration, since an additional sensor for distinguishing incident sound must be disposed outside, it is difficult to implement in terms of structure, there is a limitation in the incident sound frequency range that can be responded to, and it is difficult to respond to incident sound that is not normally incident. There is a problem.

Japanese Patent Publication P2013-164423 A (published on August 22, 2013) discloses a sonar assembly with reduced interference.

The above background art is possessed or acquired by the inventor in the process of deriving the present invention, and cannot necessarily be said to be known art disclosed to the general public prior to filing the present invention.

According to an embodiment, it is possible to provide an active reflection sound shielding device in which one sensor layer is arranged side by side, capable of responding to various sound frequency regions and responding to incident sound that is not normally incident.

An active reflection sound shielding unit according to an embodiment includes a sensor unit that detects incident sound (p ⁺ ); and a transmitter spaced apart from the sensor unit by d and canceling the radiated sound (p ⁻ ), wherein the sensor unit is formed as a single layer, and the radiated sound (p ⁻ ) is an output sound output from the transmitter. (p _t ) and the incident sound (p ⁺ ) is composed of the sum of the reflected sound (p _r ) reflected from the transmission unit, and the output sound (p _t ) of the sensor unit is the radiated sound (p ⁻ ) can be 0

의 관계를 만족할 때, [수학식 5]의 관계가 성립할 수 있다.The pressure measurable through the sensor unit is referred to as p _A , and the reflected sound ( _pr ) is a relationship obtained by multiplying the incident sound (p ⁺ ) by the reflection coefficient R,

When the relationship of is satisfied, the relationship of [Equation 5] can be established.

[Equation 5]

The output sound p _t may satisfy [Equation 6].

[Equation 6]

The incident sound (p ⁺ ) may satisfy [Equation 7].

[Equation 7]

[Equation 8] may be satisfied when the wavefront of the incident sound (p ⁺ ) is incident on the sensor unit at an angle of θ.

[Equation 8]

The active reflective sound shielding device including the active reflective sound shielding unit may include a first amplifying unit configured to amplify a signal received from the sensor unit; a phase detection unit converting the negative phase difference received from the two adjacent sensor units into a signal; a second amplifier for amplifying the output sound; and a control unit calculating a frequency from the signal received from the first amplification unit and receiving a signal corresponding to an incident angle from the phase detection unit, wherein a plurality of the active reflection sound shielding units may be arranged side by side.

In an active reflection sound shielding unit and device according to an embodiment, one sensor layer is arranged side by side to correspond to various acoustic frequency regions and to respond to incident sound that is not normally incident.

1 is a view showing a conventional active reflection sound shielding unit.
2 is a diagram illustrating an active reflection sound shielding unit according to an exemplary embodiment.
3 is a diagram illustrating an active reflection sound shielding unit according to an exemplary embodiment.
4 is a diagram illustrating an active reflection sound shielding device according to an exemplary embodiment.
5 is a diagram illustrating an embodiment of an active reflection sound shielding device according to an embodiment.

Hereinafter, embodiments will be described in detail through exemplary drawings. In adding reference numerals to components of each drawing, it should be noted that the same components have the same numerals as much as possible even if they are displayed on different drawings. In addition, in describing the embodiment, if it is determined that a detailed description of a related known configuration or function hinders understanding of the embodiment, the detailed description will be omitted.

In addition, in describing the components of the embodiment, terms such as first, second, A, B, (a), and (b) may be used. These terms are only used to distinguish the component from other components, and the nature, order, or order of the corresponding component is not limited by the term. When an element is described as being “connected,” “coupled to,” or “connected” to another element, that element may be directly connected or connected to the other element, but there may be another element between the elements. It should be understood that may be "connected", "coupled" or "connected".

Components included in one embodiment and components having common functions will be described using the same names in other embodiments. Unless stated to the contrary, descriptions described in one embodiment may be applied to other embodiments, and detailed descriptions will be omitted to the extent of overlap.

1 is a view showing a conventional reflection sound shielding unit.

Referring to FIG. 1 , a conventional reflected sound shielding unit 10 may include a sensor unit 110 formed of two layers and a transmitter 120 disposed below the sensor unit 110 to control echoes. there is. The pressures (p _a , p _b ) detected by the first sensor 111 and the second sensor 112 of the sensor unit 110 detect the sum of the incident sound (p ⁺ ) and the emitted sound (p ⁻ ), respectively. do. In this case, the radiated sound (p ^- ) is composed of the sum of the reflected sound (p _r ) of the incident sound (p ⁺ ) reflected from the transmitter 120 and the output sound (p _t ) of the transmitter 120, expressed as a relational expression Then, it is as shown in [Equation 1] below.

[Equation 1]

Here, e ^jkd is calculated in the frequency domain to implement a time delay according to each position and corresponds to a coefficient. Through [Equation 1], incident sound (p ⁺ ) and emitted sound (p ^- ) can be distinguished through p _a and p _b detected by the first sensor 111 and the second sensor 112. there is. In addition, the emitted sound (p-) is the sum of the reflected sound and the transmitted sound, and has a relationship according to [Equation 2].

[Equation 2]

인 경우 방사음(p^-)을 0으로 만들 수 있다. 방사음(p^-)을 최소화하기 위해서 종래의 기술의 적용시에는, Feedback 시스템을 이용해서 그 오차를 줄이는 여러 가지 기술을 사용한다. 한편, 종래의 기술 한계점은 위 [수학식 1]에서 기술되어 있듯이, 수신된 신호로부터 입사음(p⁺) 및 방사음(p^-)을 계산할 때 e^ikd의 계수를 사용한다는 점이다. 여기서

이며 파장

이다. 따라서 제어기는 입사음의 주파수 f가 변경되어 있지 않다고 가정을 하고 구성이 되어 있다. 또한 d의 경우로 파장의 1/4인 경우 최적의 효과를 보여주기 때문에 주파수가 변경되게 되면 제어기의 성능이 떨어지게 된다. 연구 결과에 따르면, 설계 주파수인 5.5 kHz를 벗어난 입사음이 도달했을 때, 반사음 제거 성능은 40 dB에서 급격하게 떨어지는 것이 확인되었다. 또한 추가적인 한계점은 종래의 기술은 입사음(p⁺)의 수직 입사를 기본적으로 전제하고 있다. 만일 입사음(p⁺)이 수직이 아닌, 수직에 대해서 각도 θ만큼 어긋나게 입사했을 경우 [수학식 1]은 아래와 같이 [수학식 3]으로 변형된다.Here, R is the reflectance and is defined as the ratio between the incident sound (p ⁺ ) and the reflected sound (p _r ). The prior art aims to minimize the radiated sound (p ^- ) by properly designing the controller, and according to [Equation 2]

In case of , the emission sound (p ^- ) can be made to zero. When applying the conventional technology in order to minimize the radiated sound (p ^- ), various techniques are used to reduce the error using a feedback system. Meanwhile, a limitation of the prior art is that, as described in [Equation 1] above, the coefficient of e ^ikd is used when calculating the incident sound (p ⁺ ) and the emitted sound (p ^- ) from the received signal. here

and the wavelength

am. Therefore, the controller is configured assuming that the frequency f of the incident sound is not changed. In addition, in the case of d, since the optimal effect is shown when the wavelength is 1/4, the performance of the controller deteriorates when the frequency is changed. According to the research results, it was confirmed that when the incident sound outside the design frequency of 5.5 kHz arrives, the performance of removing the reflected sound drops sharply at 40 dB. In addition, an additional limitation is that the conventional technology basically assumes normal incidence of incident sound (p ⁺ ). [Equation 1] is transformed into [Equation 3] as follows when the incident sound (p ⁺ ) is incident at an angle θ offset from the vertical, not perpendicular.

[Equation 3]

Since it is difficult to reflect the angle θ by using a single controller, the effect of reducing reflected sound is reduced even for obliquely incident sound, similar to the case where the design frequency is out of range.

2 is a diagram illustrating an active reflection sound shielding unit according to an exemplary embodiment.

Referring to FIG. 2 , the active reflection sound shielding unit 1 according to an embodiment, unlike the prior art, may be based on a single-layer sensor unit 11, not a multi-layer, and has a fixed frequency and vertical It is not limited to incidence and can be operated to correspond to various angles of incidence. In addition, since the sensor unit 11 is formed of a single layer, the overall thickness can be reduced. For example, the active reflection sound shielding unit 1 may include the sensor unit 11 and the transmission unit 12, and may be based on an array type. [Equation 4] is obtained when the relational expression of the pressure is derived for the sound incident vertically to the active reflected sound shielding unit 1.

[Equation 4]

[Equation 4] is interpreted in the time domain, and when converted to the frequency domain, [Equation 5] is obtained.

[Equation 5]

Here, the reflected sound (p _r ) is expressed by multiplying the incident sound (p ⁺ ) by the reflection coefficient R, and p _t is the output sound of the transmitter 12 . In order for the total reflected sound (p ^- ) to be 0, the output sound (p _t ) of the transmitter 12 can be calculated from [Equation 5] according to [Equation 6].

[Equation 6]

p + represents the incident sound, but the actual measurable pressure in the sensor unit 11 is p _A in FIG. 2, and using [Equation 5], the incident sound (p ⁺ ) can be calculated from p _A and p _t there is.

[Equation 7]

이고, 이는 p_t에 지연 시간을 포함한 정보이므로, 이미 이전에 송신한 신호 (

)를 기반으로 p+의 산출이 가능하며, 이를 통해서 새로운 p_t의 계산이 가능하다. In practice, p ⁺ must be known to calculate p _t for reflected sound attenuation, and p _t is required to calculate p ⁺ . However, according to the above equation, the required components of p _t are

, and since this is information including the delay time in p _t , the previously transmitted signal (

), it is possible to calculate p+, and through this, a new calculation of p _t is possible.

3 is a diagram illustrating an active reflection sound shielding unit according to an exemplary embodiment.

Referring to FIG. 3 , when an incident angle exists, when p ⁺ is obliquely incident by θ, the emitted sound (p ⁻ ) may be calculated as the sum of the reflected sound ( _pr ) and the output sound (p _t ). When the distance b between the transmitters 12 is less than 1/2 of the wavelength, both p _r and p _t may have an omnidirectional component. In the case of FIG. 3 , the incident sound (p ⁺ ) may be calculated according to [Equation 8] below.

[Equation 8]

4 is a diagram illustrating an active reflection sound shielding device according to an exemplary embodiment.

Referring to FIG. 4 , the active reflected sound shielding device 2 may include a plurality of active reflected sound shielding units 1, and the plurality of active reflected sound shielding units 1 are arranged side by side to determine the angle and frequency of the incident sound. can be detected, and incident sound can be calculated without being affected by output sound or reflected sound. For example, the active reflected sound shielding device 2 includes a sensor unit 11, a transmission unit 12, a first amplification unit 13, a phase detection unit 14, a second amplification unit 15, and a control unit 16. can include

The first amplifier 13 may amplify the signal received from the sensor unit 11 .

The phase detection unit 14 may convert a negative phase difference received from two adjacent sensor units 11 into a signal. Since the angle of incidence (θ) determines the phase difference, the angle of incidence can be processed in real time through this. On the other hand, FIG. 4 shows the implementation of the active reflected sound shielding device 2 configured in a one-dimensional array, but in the case of a shielding device configured in a two-dimensional array, the phase detector calculates the direction vector of the incident sound through three or more sensor reception signals. can do.

The control unit 16 may calculate a frequency from the signal received from the first amplification unit 13 and receive a signal corresponding to the incident angle from the phase detection unit 14 . After that, the controller 16 can calculate p _t through [Equation 6] and [Equation 8].

The second amplifier 15 may amplify the output sound. For example, a signal corresponding to p _t calculated by the control unit 16 may be amplified by the second amplifier 15 and finally converted into sound pressure p _t through the transmission unit 12 . Through such a calculation process, it is possible to implement an active sound reflection shielding device 2 capable of responding to various angles of incidence and less affected by frequency fluctuations.

5 is a diagram illustrating an embodiment of an active reflection sound shielding device according to an embodiment.

Referring to FIG. 5, an active reflection shielding unit 1 (an active reflection shielding device 2 may be disposed) corresponds to an opponent surface ship or an underwater ship (d), a sonobuoy (c), and an underwater active sensor (a). It is possible to respond to a plurality of active signals by simultaneously emitting the signals that do. In addition, it is possible to effectively respond to multi-dimensional sound detection, such as a bi-static method in which the opponent underwater ship (d) transmits and the underwater sensor (a) receives, which was impossible to respond in the past.

As described above, although the embodiments have been described with limited drawings, those skilled in the art can make various modifications and variations from the above description. For example, the described techniques may be performed in an order different from the described method, and/or components of the described structure, device, etc. may be combined or combined in a different form from the described method, or other components or equivalents may be used. Appropriate results can be achieved even if substituted or substituted by

10: Conventional reflection sound shielding unit
110: sensor unit
111: first sensor
112: second sensor
120: transmitter
1: Active reflection shielding unit
11: sensor unit
12: transmitter
13: first amplifier
14: phase detection unit
15: second amplifier
16: control unit
2: Active reflective sound shielding device

Claims (6)

a sensor unit that detects an incident sound (p+); and
A transmission unit spaced apart from the sensor unit by d and canceling radiated sound (p-);
The sensor unit,
formed in a single layer,
The radiated sound (p-) is,
The output sound (pt) output from the transmission unit and the incident sound (p+) are composed of the sum of the reflected sound (pr) reflected from the transmission unit,
The sensor unit,
The output sound pt is output so that the radiation sound p- is 0,
The pressure measurable through the sensor unit is referred to as pA, and the reflected sound (pr) is a relationship obtained by multiplying the incident sound (p+) by the reflection coefficient R,

When the relationship of is satisfied, the relationship of [Equation 5] is established,
[Equation 5]

Active reflective sound shielding unit.
delete According to claim 1,
The output sound (p _t ) is characterized in that it satisfies [Equation 6],
[Equation 6]

Active reflective sound shielding unit.
According to claim 3,
Characterized in that the incident sound (p ⁺ ) satisfies [Equation 7],
[Equation 7]

Active reflective sound shielding unit.
According to claim 4,
Characterized in that when the wavefront of the incident sound (p ⁺ ) is incident at an angle θ with respect to the sensor unit, [Equation 8] is satisfied.
[Equation 8]

Active reflective sound shielding unit.
In the active reflective sound shielding device comprising the active reflective sound shielding unit according to claim 5,
a first amplifier for amplifying the signal received from the sensor unit;
a phase detection unit converting the negative phase difference received from the two adjacent sensor units into a signal;
a second amplifier for amplifying the output sound; and
Further comprising a control unit for calculating a frequency from the signal received from the first amplification unit and receiving a signal corresponding to the incident angle from the phase detection unit;
The active reflective sound shielding device, characterized in that a plurality of active reflective sound shielding units are arranged side by side.

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