1. A vector sensor correction method based on standing wave tube and sound absorption material is characterized in that: the method comprises the following steps:

step 1: building a correction device:

the correction device comprises a standing wave tube, wherein a loudspeaker is installed at one end of the standing wave tube, a sound absorption material is placed at the other end of the standing wave tube, a vector sensor and a sound pressure sensor No. 2 are installed at the position l, away from the surface of the sound absorption material, of the wall of the standing wave tube, and a sound pressure sensor No. 1 is installed at the position l + d, away from the surface of the sound absorption material, of the wall of the standing wave tube;

step 2: generating a white noise signal through a loudspeaker, and measuring acoustic impedance Z at the position of a vector sensor by using two sound pressure sensors;

and step 3: according to the impedance value Z and the sound pressure value p measured by the No. 2 sound pressure sensor_ref2Calculating the vibration velocity u of the reference particle at the position of the vector sensor_ref：

And 4, step 4: sound pressure value p measured by vector sensor_puSound pressure value p obtained from 2 sound pressure sensor_ref2Calculating sound pressure amplitude sensitivity S_pDrawing a sound pressure sensitivity curve:

according to the vibration velocity u of the reference particle at the position of the vector sensor_refAnd the particle vibration velocity value u obtained by the test of the vector sensor_puCalculating particle vibration velocity amplitude sensitivity S_uDrawing a particle vibration velocity sensitivity curve:

and 5: from p_ref2And u_refCalculating to obtain relative phase value of theoretical sound pressure and particle vibration velocity

From p_puAnd u_puCalculating the relative phase of the tested sound pressure and the particle vibration velocity

ByAndcalculating to obtain the relative phase calibration value of the vector sensorDrawing a relative phase sensitivity curve:

2. the vector sensor correction method based on standing wave tube and sound absorption material as claimed in claim 1, wherein: the process of measuring the acoustic impedance Z at the position of the vector sensor by using the two sound pressure sensors in the step 2 is as follows:

calculating to obtain transfer functions H of incident waves in the two sound pressure sensors according to the installation position information and the sound wave number k of the two sound pressure sensors_IAnd the reflected wave transfer function H_R：

H_I＝e^-jkd,H_R＝e^jkd

From the measured values p of two sound pressure sensors_ref1、p_ref2Calculating to obtain the transfer function H of the total sound field₁₂：

According to H_I、H_pAnd H₁₂Calculating the reflection coefficient r of the sound absorption material:

calculating the acoustic impedance Z at the position of the vector sensor according to the reflection coefficient r and the characteristic impedance rho c of the air:

Background

The vector sensor is a novel sensor, and can measure the sound pressure and the particle vibration velocity at the same point, so that comprehensive sound field information is obtained. In acoustic measurements based on vector sensors to obtain correct sound field information, one key factor is the calibration of the vector sensor. The current sensitivity correction technology of the vector sensor is generally based on anechoic chamber measurement and standing wave tube test. Based on a measurement method of an anechoic chamber, an expensive acoustic measurement chamber is needed, and the low-frequency sensitivity obtained by measurement is poor in precision, so that the material cannot be quickly and conveniently tested and calibrated.

In a known standing wave tube calibration method, in an invention patent with application publication number CN 110312196 a entitled acoustic vector sensor sensitivity measurement device and system, sound pressure, particle vibration velocity and relative phase sensitivity curve graphs of the two are calculated by using data measured at different position holes, and in the method, a sound pressure sensitivity calculation formula is as follows:the particle vibration velocity sensitivity is calculated by the formulaWhere k is the wavenumber, frequency dependent, resulting in singular value points for the sensitivity curve thus measured.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a vector sensor correction method based on standing wave tubes and sound absorbing materials, wherein a smooth curve graph of the surface impedance of the materials relative to the frequency is obtained by calculation by utilizing two sound pressure sensors and the sound absorbing materials, and the surface impedance can be obtained only by converting the data obtained by the test of the vector sensors through the sensitivity, so that the sound pressure amplitude sensitivity, the particle vibration velocity amplitude sensitivity and the relative phase sensitivity curve of the vector sensors can be rapidly measured through the smooth surface impedance curve graph calculated by the sound pressure sensors, and the problem that the sensitivity curve obtained by the existing method can generate singular value points is solved.

The technical scheme of the invention is as follows:

the vector sensor correction method based on the standing wave tube and the sound absorption material comprises the following steps:

step 1: building a correction device:

the correction device comprises a standing wave tube, wherein a loudspeaker is installed at one end of the standing wave tube, a sound absorption material is placed at the other end of the standing wave tube, a vector sensor and a sound pressure sensor No. 2 are installed at the position l, away from the surface of the sound absorption material, of the wall of the standing wave tube, and a sound pressure sensor No. 1 is installed at the position l + d, away from the surface of the sound absorption material, of the wall of the standing wave tube;

step 2: generating a white noise signal through a loudspeaker, and measuring acoustic impedance Z at the position of a vector sensor by using two sound pressure sensors;

and step 3: according to the impedance value Z and the sound pressure value p measured by the No. 2 sound pressure sensor_ref2Calculating the vibration velocity u of the reference particle at the position of the vector sensor_ref：

And 4, step 4: sound pressure value p measured by vector sensor_puSound pressure value p obtained from 2 sound pressure sensor_ref2Calculating sound pressure amplitude sensitivity S_pDrawing a sound pressure sensitivity curve:

according to the vibration velocity u of the reference particle at the position of the vector sensor_refAnd the particle vibration velocity value u obtained by the test of the vector sensor_puCalculating particle vibration velocity amplitude sensitivity S_uDrawing a particle vibration velocity sensitivity curve:

and 5: from p_ref2And u_refCalculating to obtain relative phase value of theoretical sound pressure and particle vibration velocity

From p_puAnd u_puCalculating the relative phase of the tested sound pressure and the particle vibration velocity

ByAndcalculating to obtain the relative phase calibration value of the vector sensorDrawing a relative phase sensitivity curve:

further, the process of measuring the acoustic impedance Z at the position of the vector sensor by using the two sound pressure sensors in the step 2 is as follows:

calculating to obtain transfer functions H of incident waves in the two sound pressure sensors according to the installation position information and the sound wave number k of the two sound pressure sensors_IAnd the reflected wave transfer function H_R：

H_I＝e^-jkd,H_R＝e^jkd

From the measured values p of two sound pressure sensors_ref1、p_ref2The transfer of the total sound field is calculatedFunction H₁₂：

According to H_I、H_pAnd H₁₂Calculating the reflection coefficient r of the sound absorption material:

calculating the acoustic impedance Z at the position of the vector sensor according to the reflection coefficient r and the characteristic impedance rho c of the air:

advantageous effects

The method has the advantages that the vector sensor is calibrated without using professional anechoic chamber equipment; compared with the known standing wave tube calibration technology, by taking the sound absorption material as a test medium, singular points cannot be generated on certain frequency points in the measurement result, and a complete sound pressure amplitude sensitivity, particle vibration velocity amplitude sensitivity and relative phase sensitivity curve can be obtained.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1: schematic of the process of the invention;

FIG. 2: a field test layout;

FIG. 3: a vector sensor collects sound pressure (a) and particle vibration velocity (b);

FIG. 4: a first sound pressure sensor (a) and a second sound pressure sensor (b);

FIG. 5: the reflection coefficient r of the sound absorbing material;

FIG. 6: the surface impedance Z of the sound absorbing material;

FIG. 7: sound pressure sensitivity Sp;

FIG. 8: particle vibration velocity sensitivity Su;

FIG. 9: relative phase sensitivity

Detailed Description

The invention provides a vector sensor correction method based on a standing wave tube and a sound absorption material, aiming at the problems that an expensive anechoic chamber is needed in anechoic chamber measurement and a high-precision sensitivity correction curve cannot be obtained.

As shown in FIG. 1, the standing wave tube has a radius D and a material thickness L. The loudspeaker is placed at one end of the standing wave tube, sound absorption materials are placed at the other end of the standing wave tube, a one-dimensional vector sensor and a No. 2 sound pressure sensor are placed at a position l away from the surface of the sound absorption materials, a No. 1 sound pressure sensor is placed at a position l + d away from the surface of the sound absorption materials, and the two sound pressure sensors measure the surface impedance of the materials. The one-dimensional vector sensor measures the response values of sound pressure and particle vibration speed.

By using the device, the sensitivity is measured, and the flow for correcting the vector sensor is as follows:

1. the loudspeaker sends out a white noise signal, and the one-dimensional vector sensor and the two sound pressure sensors simultaneously record the white noise signal obtained by measurement.

2. Calculating the incident wave transfer function H of the two sound pressure sensors according to the position information and the sound wave number k_IAnd the reflected wave transfer function H_R：

H_I＝e^-jkd,H_R＝e^jkd

3. From the measured values p of two sound pressure sensors_ref1、p_ref2Solving the transfer function H of the total sound field₁₂：

4. By the transfer function H of the incident wave_IThe reflected wave transfer function H_pAnd the transfer function H of the total sound field₁₂Calculating the reflection coefficient r of the sound absorption material:

5. calculating the acoustic impedance Z at the position of the vector sensor according to the reflection coefficient r and the characteristic impedance rho c of the air:

6. according to the impedance value Z and the sound pressure value p measured by the No. 2 sound pressure sensor_ref2Obtaining the vibration velocity u of the reference particle at the position of the vector sensor_ref：

7. Sound pressure value p measured by vector sensor_puSound pressure value p obtained from 2 sound pressure sensor_ref2Calculating sound pressure amplitude sensitivity S_pDrawing a sound pressure sensitivity curve:

8. from the reference particle vibration velocity u_refAnd the particle vibration velocity value u obtained by the test of the vector sensor_puCalculating particle vibration velocity amplitude sensitivity S_uDrawing a particle vibration velocity sensitivity curve:

9. sound pressure value p measured by number 2 sound pressure sensor_ref2Phase value ofThe vibration velocity u of the reference particle at the position of the vector sensor_refPhase value ofCalculating to obtain relative phase value of theoretical sound pressure and particle vibration velocity

10. Sound pressure value p measured by vector sensor_puPhase value ofAnd the particle vibration velocity value u obtained by the test of the vector sensor_puPhase value ofCalculating the relative phase of the tested sound pressure and the particle vibration velocity

11. ByAndcalculating to obtain the relative phase calibration value of the vector sensorThus, a relative phase sensitivity curve is plotted:

the field test layout of this embodiment is shown in fig. 2, where the diameter of the standing wave tube is 10cm, the speaker is placed at the right end of the standing wave tube, seven pieces of glass fiber cotton with the thickness of 5cm are placed at the left end, the distance l between the one-dimensional vector sensor and the second acoustic pressure sensor from the surface of the material is 10cm, and the distance d between the first acoustic pressure sensor and the second acoustic pressure sensor is 5 cm.

The loudspeaker selects a white noise signal to sound for 30s, the data acquired by the three sensors is intercepted, and the data between 15s and 25s is shown in figures 3 and 4. The reflection coefficient r of the glass fiber wool calculated by the first and second acoustic pressure sensors is shown in fig. 5, the surface impedance Z is shown in fig. 6, the calculated acoustic pressure sensitivity curve is shown in fig. 7, the calculated particle vibration velocity sensitivity curve is shown in fig. 8, and the calculated relative phase sensitivity curve is shown in fig. 9. It can be seen that the complete sound pressure amplitude sensitivity, particle vibration velocity amplitude sensitivity and relative phase sensitivity curve of the vector sensor can be rapidly measured by the smooth surface impedance curve calculated by the sound pressure sensor.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made in the above embodiments by those of ordinary skill in the art without departing from the principle and spirit of the present invention.