Active noise reduction hearing conservation device

Abstract

The application discloses an active noise reduction protection device with hearing maintenance function, which comprises a wearing belt and a pair of ear muffs installed at both ends of the wearing belt, an active noise reduction protection module and a music maintenance module are installed in the ear muffs, the active noise reduction protection module is used for reducing environmental noise and residual noise in the ear muffs; the music maintenance module comprises a microcontroller, a decoding module, a display and control module and a music compensation module, is used for playing music to maintain hearing; the music compensation module is used for compensating low-frequency music attenuated due to noise reduction and playing real music in the working state of the active noise reduction protection module. The application can be applied to workers in a high-noise environment for a long time in a cabin of a ship or a helicopter, and helps to reduce the influence of noise on the workers and maintain hearing through the technology of listening to soothing music under the premise of noise protection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of noise governance, and more particularly to an active noise reduction protection device with auditory maintenance function. BACKGROUND

[0002] The ship and helicopter cabin workers work and live in the noise environment for a long time, and are greatly affected by the ship and aircraft power system and other equipment noise. Working in the high noise environment for a long time not only causes hearing loss, but also causes psychological restlessness, attention decline and the like. In some special positions, protective earmuffs are equipped to reduce the influence of noise on personnel, but the hearing damage is an accumulative process, which needs to be actively responded.

[0003] According to the actual measurement statistics, the noise of the ship is more than 60dB for a long time even when the ship is sailing at low speed, which does not meet the requirement of the fourth level of night rest required by the Standard for Urban Regional Noise of the People's Republic of China (GB3096-93); and the noise of the helicopter is even more than 101dB when the helicopter is working, which does not meet the noise standard (85dB, not more than 90dB) of the industrial enterprise production workshop and working place of the Industrial Enterprise Noise Control Design Specification (GB / T50087-2013). SUMMARY

[0004] 1. Technical problem to be solved

[0005] In view of the problems in the prior art, the purpose of the present application is to provide an active noise reduction protection device with auditory maintenance function, which can be applied to some workers in the ship and helicopter cabin who are in the high noise environment for a long time, and helps to reduce the influence of noise on the workers and maintain the hearing under the premise of noise protection through the technology of listening to soothing music.

[0006] 2. Technical scheme

[0007] In order to solve the above problems, the present application adopts the following technical scheme.

[0008] An active noise reduction protection device with auditory maintenance function comprises a wearing belt and a pair of earmuffs installed at both ends of the wearing belt, and an active noise reduction protection module and a music maintenance module are installed in the earmuffs. The active noise reduction protection module is used for reducing the environmental noise and the residual noise in the earmuffs. The music maintenance module comprises a microcontroller, a decoding module, a display and control module and a music compensation module, and is used for playing music for hearing maintenance. The music compensation module is used for power amplification of low-frequency music through a power amplification circuit in the working state of the active noise reduction protection module, so as to compensate for the low-frequency music attenuated due to noise reduction and play real music.

[0009] Further, the microcontroller is used for music storage, and is used for music reading, volume control, track switching, and playing control of playing stop;

[0010] The decoding module is used for decoding music, so that the microcontroller plays the music;

[0011] The display control module is used for controlling and displaying the playing state of the music.

[0012] Further, the music maintenance module is further provided with a shell which is detachably installed in the earmuff; the shell is provided with a power switch which is electrically connected with the active noise reduction protection module.

[0013] Further, the active noise reduction protection module comprises an error microphone, a reference microphone, a secondary sound source, a first preamplifier, a second preamplifier, an open-loop controller, a closed-loop controller, a power amplifier and an adder;

[0014] The reference microphone, the first preamplifier, the open-loop controller, the adder, the power amplifier and the secondary sound source are sequentially connected to form a feed-forward noise reduction system, and are used for reducing environmental noise;

[0015] The error microphone, the second preamplifier, the closed-loop controller, the adder, the power amplifier and the secondary sound source are sequentially connected to form a feedback noise reduction system, and are used for reducing residual noise in the earmuff.

[0016] Further, the open-loop controller is a first-order filter, and the closed-loop controller is a second-order filter.

[0017] Further, the secondary sound source microphone and the error microphone are horizontally arranged and arranged inside the earmuff; the reference microphone is arranged outside the earmuff.

[0018] Further, the wearing band is further provided with a processor module and a communication module; the processor module is connected with a cloud server and a user mobile device through the communication module.

[0019] Further, the earmuff comprises an outer cover, an inner cover and a fitting ring band, and the outer cover, the inner cover and the fitting ring band are sequentially installed from outside to inside and constitute a complete annular structure.

[0020] 3. Beneficial effects

[0021] Compared with the prior art, the application has the following advantages:

[0022] (1) The active noise reduction protection device with hearing maintenance function is adopted in the application, the hearing maintenance function is added to the protective earmuff, and the protective earmuff with specific type of music and the function of listening to music at any time is selected, so that the staff can help to relieve the tension of eardrum, reduce psychological pressure, improve work efficiency and perform hearing maintenance at any time during work intervals.

[0023] (2) This scheme can be applied to some workers in the high noise environment for a long time in the cabin of the ship and helicopter, and under the premise of noise protection, the influence of noise on the workers is reduced through the technology of listening to soothing music, and hearing conservation is carried out. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is an external structure schematic diagram of the active noise reduction protection device of the application;

[0025] Figure 2 It is a structure schematic diagram of the active noise reduction module of the application;

[0026] Figure 3 It is a structure schematic diagram of the music playing module of the application;

[0027] Figure 4 It is a network module schematic diagram of the active noise reduction protection device of the application;

[0028] Figure 5 It is a noise reduction circuit principle block diagram of the active noise reduction module of the active noise reduction protection device of the application;

[0029] Figure 6 It is a music compensation circuit principle block diagram of the music playing module of the active noise reduction protection device of the application.

[0030] Explanation of reference numerals in the drawing:

[0031] 1 wearing belt, 2 ear cover, 3 cloud server, 4 user mobile device, 5 error microphone, 6 reference microphone, 7 secondary sound source, 8 microcontroller, 9 conservation module, 10 decoding module, 11 display control module, 12 compensation module, 13 battery, 14 shell upper cover, 15 shell base. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the application; obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application, and all other embodiments obtained by those skilled in the art without creative labor on the basis of the embodiments in the application belong to the protection scope of the application.

[0033] In the description of the present application, it should be noted that the terms "upper", "lower", "inner", "outer", "top / bottom end" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0034] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "provided with", "sleeved / connected", "connected" and the like should be broadly understood, for example, "connected" can be fixedly connected, can also be detachably connected, or integrally connected; can be mechanically connected, can also be electrically connected; can be directly connected, can also be indirectly connected through an intermediate medium, can be internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0035] Embodiment:

[0036] Please refer to Figure 1 An active noise reduction protection device with hearing conservation function, comprising a wearing band 1 and a pair of ear covers 2 mounted at both ends of the wearing band 1, an active noise reduction protection module and a music conservation module are mounted in the ear cover 2, the active noise reduction protection module is used for noise reduction of environmental noise and residual noise in the ear cover; the music conservation module includes a microcontroller 8, a decoding module 10, a display and control module 11 and a music compensation module 12, which is used for playing music for hearing conservation; the music compensation module is used for power amplification of low-frequency music through a power amplifier circuit in the working state of the active noise reduction protection module, so as to compensate for the low-frequency music attenuated by noise reduction and play real music.

[0037] In the above embodiment, a wearing band 1 can be provided between the pair of ear covers 2 to fix the ear covers on the ears. Considering the working environment and safety, the wearing band 1 is used to increase the firmness and prevent the ear covers 2 from falling off. When the head does not need to move, the ear covers 2 can be directly worn.

[0038] In the above embodiment, please refer to Figure 2 The active noise reduction protection module adopts a composite active noise reduction control method, including a feedforward noise control system and a feedback noise control system, which is used for noise reduction of external noise and playing original music. Specifically, the active noise reduction module includes an error microphone 5, a reference microphone 6, a secondary sound source 7, a first preamplifier, a second preamplifier, an open-loop controller, a closed-loop controller, a power amplifier and an adder;

[0039] The reference microphone 6, the first preamplifier, the open-loop controller, the adder, the power amplifier and the secondary sound source are sequentially connected to form a feed-forward noise reduction system, which is used for reducing environmental noise; the feed-forward system is mainly characterized in that the noise elimination loop is open-loop, which is convenient for maintaining the stability of the system; the pickup microphone is far away from the secondary sound source 7 outside the earmuff 2, and the noise signal collected by the pickup microphone is less affected by the receiver, which is relatively easy to realize in circuit and convenient for system debugging;

[0040] The error microphone 5, the second preamplifier, the closed-loop controller, the adder, the power amplifier and the secondary sound source 7 are sequentially connected to form a feedback noise reduction system, which is used for reducing residual noise in the earmuff; the feedback noise control system automatically adjusts through a closed-loop feedback, and is more accurate in feedback of noise near the ear, and has a better noise reduction effect than the feed-forward system; for specific noise reduction circuit principle diagram, please refer to Figure 5 .

[0041] The preamplification circuit mainly amplifies the noise signals picked up by the reference microphone 6 and the error microphone 5 to the required amplitude, and inverts the picked-up noise signals after superposition with the phase shift network.

[0042] The control filter circuit mainly realizes a signal phase shift network; specifically, a second-order filter is used as a closed-loop controller, and a first-order filter is used as an open-loop controller.

[0043] The secondary sound source 7 circuit needs to power amplify the noise signals output by the microphone amplification circuit to drive the secondary sound source loudspeaker, so that the secondary sound source 7 generates a signal of sufficient size and opposite phase to the noise signal to cancel the noise signal.

[0044] In the above embodiment, please refer to Figure 3 , the music maintenance module further comprises a maintenance module 9 and a battery 13; wherein,

[0045] The microcontroller 8 is used for reading and controlling the playing of the maintenance music; the microcontroller 8 adopts an ARM microcontroller, which is a master control unit for music reading, volume control, track switching, playing stop and other functions of the maintenance module 9;

[0046] The maintenance module 9 is used for saving the pre-set maintenance music; the maintenance module 9 is used for storing music tracks; the selection of the tracks is set according to the identified maintenance listening tracks of the working environment, or can be set and saved according to the personal preference of the working staff;

[0047] The decoding module 10 is used for decoding the maintenance music, so that the microcontroller 8 plays; the decoding module 10 is an MP3 digital music decoding electronic module, which decodes the music files in the maintenance module 9 and transmits them to the ARM microcontroller 8 to play the maintenance music;

[0048] The display control module 11 is used to operate and display the playing state of the maintenance music; the display control module 11 is used to display the state of the music file, to set the volume control, to switch the track control, and to stop the music playing. In the non-operation state, the display control module 11 will make the liquid crystal display screen automatically sleep, and once there is a touch control, it will automatically light up for control;

[0049] The battery 13 is used for power supply of the hearing maintenance module;

[0050] The compensation module 12, in the working state of the active noise reduction protection module, performs power amplification on the low-frequency music through the power amplification circuit, realizes compensation for the low-frequency music attenuated due to noise reduction, plays real music, and enables the played music to be presented completely and accurately. The specific music compensation circuit principle diagram is referred to Figure 6 .

[0051] In the above embodiment, the power amplification circuit is determined according to the sound pressure loss of the active noise reduction protection module in the noise reduction process. The specific music compensation process is as follows:

[0052] 1) Determine the compensation coefficient:

[0053] The reference microphone 6 collects the noise source of a specific environment and converts it into noise data. The noise data is analyzed and processed. The processing basis is that the noise source is composed of a plurality of (or infinite) frequency components, and the data needs to be processed in the frequency domain. The time domain signal is converted into a frequency domain signal. The sound is divided into multiple frequency bands using 1 / 3 octave. The sound pressure level of each octave is calculated. The final sound pressure is weighted using the A rate coefficient to represent the noise source display, and the unit is d BA. The sound pressure calculation formula of each frequency band is:

[0054]

[0055] The A rate coefficient formula is:

[0056]

[0057] The final sound pressure calculation formula of all frequency bands is:

[0058]

[0059] Therefore, the A rate coefficient obtained is the correction coefficient of the active noise reduction, and is also the compensation coefficient of the music compensation.

[0060] 2) Perform active noise reduction:

[0061] The control filter adjusts the preset noise reduction weight coefficient according to the correction coefficient, and performs filter noise reduction by adaptive algorithm; the following formula is used for noise reduction:

[0062]

[0063] Wherein: x(n) is a reference signal; S(z) is an error channel; x'(n) is a filtered secondary signal; y(n) is a secondary signal; e(n) is an error signal.

[0064] 3) Perform music compensation

[0065] The music compensation module receives compensation coefficients, and corrects the compensation coefficients through the power amplification circuit to realize compensation for low-frequency music attenuated due to noise reduction, so that real music can be played.

[0066] Because in music maintenance, the selection of music is generally soothing music with generally low sound pressure, and the low-frequency music of the soothing music coincides with the frequency of the noise source in the noise reduction process, in order to compensate for the sound pressure of the music lost due to noise reduction, compensation is needed to obtain real maintenance music.

[0067] In the above embodiment, the music maintenance module further comprises a shell which is detachably mounted in the earmuff 2; the shell is provided with a power switch electrically connected with the active noise reduction protection module. The shell has a shell upper cover 14, a shell base 15 and a buckle. The shell upper cover 14 cooperates with the shell base 15 to assemble the microcontroller 8, the maintenance module 9, the decoding module 10, the display control module 11, the music compensation module 12 and the battery 13 in the interior, thereby achieving module installation. The buckle is used to realize quick installation and disassembly in the interior of the earmuff 2.

[0068] In the above embodiment, the frequency range of the low-frequency music is the same as that of the external noise and the residual noise. The frequency range of the low-frequency music is 100-3000 Hz.

[0069] In the above embodiment, referring to Figure 2 , the secondary sound source 7 microphone and the error microphone 5 are horizontally arranged and arranged in the interior of the earmuff 2; the reference microphone 6 is arranged outside the earmuff 2.

[0070] In the above embodiment, referring to Figure 4 , the processor module and the communication module are further mounted in the band 1; the processor module is connected with the cloud server 3 and the user mobile device 4 through the communication module; the cloud server 3 and the user mobile device 4 are connected through a big data networking mode, so that not only the music preferred by the user and the music suitable for the current noise environment can be provided more scientifically and accurately, but also the user can select and control the music through the user mobile device 4.

[0071] In the above embodiment, the earmuff 2 comprises an outer cover, an inner cover and a fitting ring, and the outer cover, the inner cover and the fitting ring are sequentially mounted from the outside to the inside and constitute a complete annular structure.

[0072] The present application introduces a secondary sound wave with the same amplitude and opposite phase of the original noise sound wave into the active noise reduction protective earmuff by applying electronic technology and electro-acoustic devices, so that the noise generated by the secondary sound wave and the original noise cancel each other out in a certain area, thereby achieving the purpose of reducing noise. In the implementation process, both feedforward noise control system and feedback noise control system are adopted. The main feature of the feedforward noise control system is that the noise elimination loop is open loop, which is convenient for maintaining the stability of the system; the pickup microphone is far away from the secondary sound source outside the earphone, so that the noise signal collected is less affected by the receiver, and the circuit implementation is relatively easy, and the system debugging is convenient; the feedback noise control system automatically adjusts through the closed loop feedback, which is more accurate in feedback of the noise near the ear, and the noise reduction effect is better than that of the feedforward type; the music playing module adopts a mature MP3 decoding module, and since the impedance of the equipment communication earphone on the ship and the helicopter is large, and the main sound frequency is mainly medium frequency, a power amplification circuit and an audio compensation circuit are designed to compensate the final output, so that the perfect reproduction of the real music is obtained.

[0073] The present application is applied to the workers in the high noise environment for a long time in the cabin of the ship and the helicopter, and helps to reduce the influence of the noise on the workers and maintain the hearing under the premise of noise protection by listening to the soothing music.

[0074] The above is only the preferred embodiment of the present application; however, the protection scope of the present application is not limited to this. Any skilled person in the art can make equivalent replacement or change according to the technical solution and the improvement concept of the present application within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. An active noise-canceling protective device with hearing protection function, comprising a wearing strap and a pair of earmuffs installed at both ends of the wearing strap, characterized in that: The earcups are equipped with an active noise cancellation module and a music maintenance module. The active noise reduction module is used to reduce ambient noise and residual noise inside the earcups; The music maintenance module includes a microcontroller, a decoding module, a display and control module, and a music compensation module, used to play music for hearing maintenance. The music compensation module compensates for low-frequency music attenuation caused by noise reduction when the active noise cancellation module is in operation, playing the true music. The low-frequency music is amplified using a power amplifier circuit. The music compensation process is as follows: The A-rate coefficient is determined to be the compensation coefficient for music compensation and also the correction coefficient for active noise reduction; the formula for the A-rate coefficient is: Where f is the frequency; The control filter of the active noise reduction and protection module adjusts the preset noise reduction weight coefficient according to the correction coefficient to perform adaptive algorithm filtering and noise reduction; The music compensation module receives the compensation coefficient and corrects the compensation coefficient through the power amplification circuit, thereby compensating for the low-frequency music that has been attenuated due to noise reduction and playing the true music.

2. The active noise reduction and protection device with hearing protection function according to claim 1, characterized in that: The microcontroller is used for music storage and for playback control, including music reading, volume control, track switching, and playback stop. The decoding module is used to decode the music, enabling the microcontroller to play the music; The display and control module is used to control and display the playback status of the music.

3. The active noise reduction and protection device with hearing protection function according to claim 1, characterized in that: The music maintenance module also has a housing that is detachably installed inside the earcups; the housing has a power switch that is electrically connected to the active noise cancellation module.

4. The active noise reduction and protection device with hearing protection function according to claim 1, characterized in that: The active noise reduction and protection module includes an error microphone, a reference microphone, a secondary sound source, a first preamplifier, a second preamplifier, an open-loop controller, a closed-loop controller, a power amplifier, and an adder. The reference microphone, the first preamplifier, the open-loop controller, the adder, the power amplifier, and the secondary sound source are sequentially connected to form a feedforward noise reduction system for reducing the ambient noise. The error microphone, the second preamplifier, the closed-loop controller, the adder, the power amplifier, and the secondary sound source are sequentially connected to form a feedback noise reduction system for reducing the residual noise inside the earmuffs.

5. An active noise reduction and protection device with hearing protection function according to claim 4, characterized in that: The open-loop controller is a first-order filter, and the closed-loop controller is a second-order filter.

6. The active noise reduction and protection device with hearing protection function according to claim 4, characterized in that: The secondary sound source microphone and the error microphone are horizontally positioned inside the earcup; the reference microphone is positioned outside the earcup.

7. The active noise reduction and protection device with hearing protection function according to claim 1, characterized in that: The wearable strap also contains a processor module and a communication module. The processor module connects to the cloud server and the user's mobile device through the communication module.

8. The active noise reduction and protection device with hearing protection function according to claim 1, characterized in that: The earmuffs include an outer cover, an inner cover, and a fitting ring band, and the outer cover, the inner cover, and the fitting ring band are installed sequentially from the outside to the inside to form a complete ring structure.

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