Device for suppressing and compensating noise in vehicle cab

Abstract

The invention relates to the technical field of noise balance control technologies, in particular to a vehicle cab noise suppression and compensation device which comprises a sealing box, a battery bin, a signal acquisition module, a signal processing module and a signal output module. An engine rotating speed signal and a microphone signal are collected; processing and analyzing the acquired data; according to the noise control device, the sound pressure level of noise in the vehicle can be reduced, the noise can be compensated, the overall sound quality in the vehicle can be improved, the miniaturized noise control device can be placed in a vehicle cab, installation is convenient, the use method is simple, and the noise control device is suitable for popularization and application. Therefore, the problem that the noise control device in the commercial vehicle cab is single in function is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of noise equalization control technology, and particularly to a device for suppressing and compensating noise in a vehicle cab. Background Art

[0002] With the continuous increase in the power of modern automobile engines and the average vehicle speed, the problem of vehicle interior noise has become increasingly prominent. The noise control in the vehicle cab has become an important indicator for evaluating the ride comfort of commercial vehicles. Installing an active noise control device in the vehicle cab can suppress low-frequency noise, effectively control the sound pressure level in the commercial vehicle cab, and improve the ride comfort of the vehicle.

[0003] However, most of the noise control devices in commercial vehicle cabs on the market have a single function and only reduce the sound pressure level. A simple sound pressure level reduction device cannot completely solve the annoyance problem in the cab and ignores the improvement of the sound quality inside the vehicle. Summary of the Invention

[0004] The purpose of the present invention is to provide a device for suppressing and compensating noise in a vehicle cab, aiming to solve the problem of the single function of the noise control device in the commercial vehicle cab.

[0005] To achieve the above purpose, the present invention provides a device for suppressing and compensating noise in a vehicle cab, including a sealed box, a battery compartment, a signal acquisition module, a signal processing module, and a signal output module;

[0006] The battery compartment is installed in the sealed box and is connected to the signal acquisition module. The signal acquisition module, the signal processing module, and the signal output module are connected in sequence and are all installed in the sealed box;

[0007] The sealed box is used for installing the battery compartment, the signal acquisition module, the signal processing module, and the signal output module;

[0008] The battery compartment is used for supplying power to the entire device;

[0009] The signal acquisition module is used for acquiring the engine speed signal and the noise signal in the cab;

[0010] The signal processing module is used for processing and analyzing the acquired signals, and generating a cancellation noise signal with a phase opposite to that of the noise, the same frequency and amplitude, and an enhancement signal for compensating the noise;

[0011] The signal output module is used for outputting the cancellation noise signal and the enhancement signal.

[0012] Among them, the signal acquisition module includes a microphone drive circuit, an electret microphone body, an engine speed sensor, and an audio power amplifier circuit; the microphone drive circuit is connected to the electret microphone body;

[0013] The microphone drive circuit is used to drive the microphone to work;

[0014] The electret microphone body is used to collect the noise signal in the cab;

[0015] The engine speed sensor is used to collect the engine speed signal;

[0016] The audio power amplifier circuit is used to amplify the collected noise signal.

[0017] Among them, the signal processing module includes an engine speed acquisition unit, a microcontroller, and an audio decoding unit, and the engine speed acquisition unit, the microcontroller, and the audio decoding unit are connected in sequence.

[0018] The engine speed acquisition unit is used to acquire the engine speed signal and transmit it to the microcontroller through CAN communication;

[0019] The microcontroller is used for the operation of the noise equalization control algorithm;

[0020] The audio decoding unit is used to decode the collected audio signal.

[0021] Among them, the signal output module includes a power amplifier and a speaker, and the power amplifier is connected to the speaker;

[0022] The power amplifier is used to amplify the processed noise signal and output it to the speaker;

[0023] The speaker is used to convert the noise cancellation signal into a sound wave with a phase opposite to that of the primary signal.

[0024] Among them, the microcontroller uses ADSP-21489, the audio decoding unit uses an AD1939 chip, and the engine speed acquisition unit uses an STM32F407 chip.

[0025] A device for suppressing and compensating noise in a vehicle cab according to the present invention includes a sealed box, a battery compartment, a signal acquisition module, a signal processing module, and a signal output module. The battery compartment is installed inside the sealed box and is connected to the signal acquisition module. The signal acquisition module, the signal processing module, and the signal output module are connected in sequence and are all installed inside the sealed box. The sealed box is used for installing the battery compartment, the signal acquisition module, the signal processing module, and the signal output module. The battery compartment is used for supplying power to the entire device. The signal acquisition module is used for acquiring the engine speed signal and the noise signal inside the cab. The signal processing module is used for processing and analyzing the acquired signals, and generating a cancellation noise signal with a phase opposite to that of the noise, the same frequency and amplitude, and an enhancement signal for compensating the noise. The signal output module is used for outputting the cancellation noise signal and the enhancement signal. By acquiring the engine speed signal and the microphone signal, processing and analyzing the acquired data, and amplifying and outputting the processed noise signal to the speaker, the present invention can reduce the sound pressure level of the noise inside the vehicle, and can also compensate for the noise and improve the overall sound quality inside the vehicle, thereby solving the problem of the single function of the noise control device in the commercial vehicle cab. Brief Description of the Drawings

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts.

[0027] Figure 1 FIG. is a schematic structural diagram of a device for suppressing and compensating noise in a vehicle cab provided by the present invention.

[0028] Figure 2 FIG. is a schematic structural diagram of a device for suppressing and compensating noise in a vehicle cab after removing the upper cover.

[0029] Figure 3 FIG. is a schematic structural diagram of the signal acquisition module.

[0030] Figure 4 FIG. is a schematic structural diagram of the signal processing module.

[0031] Figure 5 FIG. is a schematic structural diagram of the signal output module.

[0032] Figure 6 FIG. is a block diagram of the hybrid ANE algorithm.

[0033] Figures 7 to 9 FIG. is the noise spectrum under the condition of 60 - 80 KM / h.

[0034] Figures 10 to 11 It is a schematic diagram showing the change in sound quality before and after compensation on the driver's side and the co-driver's side.

[0035] In the figure: 1 - sealed box, 2 - battery compartment, 3 - signal acquisition module, 4 - signal processing module, 5 - signal output module, 11 - reserved hole, 12 - portable handle, 21 - main power switch, 22 - charging port, 31 - microphone drive circuit, 32 - electret microphone body, 33 - engine speed sensor, 34 - audio power amplifier circuit, 41 - engine speed acquisition unit, 42 - microcontroller, 43 - audio decoding unit, 51 - power amplifier, 52 - speaker; 101 - connecting wire 1, 102 - connection port, 103 - power supply wire, 104 - signal wire 1, 105 - power supply wire 1, 106 - power supply wire 2, 107 - signal wire 2, 108 - microphone extension head, 109 - microphone extension wire, 110 - power supply wire 3, 111 - signal wire 3. Specific embodiments

[0036] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements with the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0037] Please refer to Figures 1 to 11 , the present invention provides a device for suppressing and compensating noise in a vehicle cab, including a sealed box 1, a battery compartment 2, a signal acquisition module 3, a signal processing module 4 and a signal output module 5;

[0038] The battery compartment 2 is installed in the sealed box 1 and is connected to the signal acquisition module 3. The signal acquisition module 3, the signal processing module 4 and the signal output module 5 are connected in sequence and are all installed in the sealed box 1;

[0039] The sealed box 1 is used to install the battery compartment 2, the signal acquisition module 3, the signal processing module 4 and the signal output module 5;

[0040] The battery compartment 2 is used to supply power to the overall device;

[0041] The signal acquisition module 3 is used to acquire the engine speed signal and the noise signal in the cab;

[0042] The signal processing module 4 is used to process and analyze the acquired signals, and generate a cancellation noise signal with the opposite phase, the same frequency and amplitude as the noise, and an enhancement signal for compensating the noise;

[0043] The signal output module 5 is used to output a noise cancellation signal and an enhancement signal.

[0044] In this embodiment, the electret microphone body 32 has a microphone extension head 108, a microphone extension wire 109, a power supply wire III 110, and a signal wire III 111; the sealed box 1 has a reserved hole 11 and a portable handle 12; the battery compartment 2 has a main power switch 21 and a charging port 22; the speaker 52 has two connection wires I 101, two connection ports 102, a power supply wire 103, and a signal wire I 104; the signal acquisition module 3 has a power supply wire I 105; the signal processing module 4 has a power supply wire II 106 and a signal wire II 107. By collecting the engine speed signal and the microphone signal, processing and analyzing the collected data, and amplifying the processed noise signal and outputting it to the speaker 52, the present invention can reduce the in-vehicle noise sound pressure level, and can also compensate for the noise and improve the overall sound quality in the vehicle, thereby solving the problem of the single function of the noise control device in the commercial vehicle cab.

[0045] Further, the signal acquisition module 3 includes a microphone drive circuit 31, an electret microphone body 32, an engine speed sensor 33, and an audio power amplifier circuit 34; the microphone drive circuit 31 is connected to the electret microphone body 32;

[0046] The microphone drive circuit 31 is used to drive the microphone to work;

[0047] The electret microphone body 32 is used to collect the noise signal in the cab;

[0048] The engine speed sensor 33 is used to collect the engine speed signal;

[0049] The audio power amplifier circuit 34 is used to amplify the collected noise signal.

[0050] In this embodiment, the signal acquisition module 3 is powered by a 24V power supply, integrates the microphone drive circuit 31 and the audio power amplifier circuit 34, and can realize the control of four microphones and four speakers. The power amplifier chip uses a TDA7850 power amplifier chip, which is a class-AB audio power amplifier chip based on MOSFET technology, specially designed for high-power car radios, and is also responsible for driving the microphone. In addition, the signal acquisition module 3 is also responsible for DC-DC conversion and power interface expansion work, so as to realize the multi-channel power supply requirements, such as the signal processing module 4, the power supply of 5V voltage, the speaker microphone. The error sensor is responsible for monitoring the error signal in the control area and providing feedback to the controller immediately, and plays a key role in adjusting the weight coefficient of the filter of the noise control algorithm; an electret microphone with a sensitivity of -10dV is selected.

[0051] Further, the signal processing module 4 includes an engine speed acquisition unit 41, a microcontroller 42, and an audio decoding unit 43, and the engine speed acquisition unit 41, the microcontroller 42, and the audio decoding unit 43 are connected in sequence.

[0052] The engine speed acquisition unit 41 is configured to acquire an engine speed signal and transmit it to the microcontroller 42 through CAN communication;

[0053] The microcontroller 42 is used for the operation of the noise equalization control algorithm;

[0054] The audio decoding unit 43 is configured to decode the collected audio signal.

[0055] The microcontroller 42 uses an ADSP-21489, the audio decoding unit 43 uses an AD1939 chip, and the engine speed acquisition unit 41 uses an STM32F407 chip.

[0056] In this embodiment, the signal processing module 4 is powered by a 5V power supply, integrates the signal processing module 4, the audio decoding module, and the engine speed acquisition module, and simultaneously reserves a microphone input interface and a noise cancellation output interface. This patent uses an ADSP-21489 chip as the microcontroller 42, which is responsible for the operation of the noise equalization control algorithm, involving a large number of multiplication and addition operations, convolution shifting, and floating-point calculations; uses an AD1939 chip to implement audio signal processing, which has a 24-bit precision, can process a sampling rate of 8 to 192 kHz, and has a differential chip with 4 inputs and 8 outputs; uses an STM32F407 chip to acquire the engine speed and transmits the speed signal to the ADSP-21489 chip through CAN communication.

[0057] Hybrid ANE algorithm, the block diagram of which is as Figure 1 shown.

[0058] In the algorithm, s(n) is the cancellation noise signal after passing through the secondary channel, and z′(n) is the compensation enhancement signal after passing through the secondary channel. Its expression is:

[0059] s(n) = y(n) * h m (n)

[0060] = [x(n) w a (n)] * h m (n) (2.9)

[0061] z′(n) = z(n) * h m (n)

[0062] = [x(n) wb (n)]*h m (n) (2.10)

[0063] where w a (n) and w b (n) are filter coefficients for canceling and compensating noise, respectively updating the filter weight coefficients of both. h m (n) is the impulse response coefficient of the actual secondary channel H m (z).

[0064] The residual noise e(n) of the hybrid ANE algorithm can be expressed as:

[0065] e(n) = d(n) + s(n) + z′(n) (2.11)

[0066] In the algorithm block diagram, G(n) is the gain noise signal, and its expression is:

[0067] G(n) = g(n)x(n) (2.12)

[0068] According to equation (2.12), the enhanced signal e g (n) can be obtained, and its expression is:

[0069] e g (n) = G(n) + z′(n)

[0070] = e(n)g(n) + z′(n) (2.13)

[0071] x(n) is the current ambient noise signal. Let G be the maximum gain ability, and the formula for its gain coefficient g(n) can be expressed as:

[0072]

[0073] In the formula, A(n) is the target output level, and can also be regarded as the gain value after signal transmission adjustment. Then it can be deduced that A(n - 1) is the gain value before adjustment, and its expression of A(n) is:

[0074] A(n) = A(n - 1) + α(env(n) - A(n - 1)) (2.15)

[0075] In the above formula, α is the dynamic adjustment rate, and env(n) is the formula of the Dynamic Equalization Shaping (DES) filter, and is also the envelope value of the current input signal. Its expression is:

[0076] env(n) = max(|x(n)|, 0.999env(n - 1)) (2.16)

[0077] In the formula, 0.999 is the smoothing coefficient, which is used to control the smoothness of the envelope of the input signal. The closer the smoothing coefficient is to 1, the smoother the signal envelope; conversely, the closer it is to 0, the more sensitive the signal envelope is.

[0078] Finally, according to the NALMS algorithm filter weight coefficient iteration equation, the update expressions of the cancellation filter coefficient and the enhancement filter coefficient can be obtained:

[0079]

[0080] Furthermore, the signal output module 5 includes a power amplifier 51 and a speaker 52, and the power amplifier 51 is connected to the speaker 52;

[0081] The power amplifier 51 is used to amplify the processed noise signal and output it to the speaker 52;

[0082] The speaker 52 is used to convert the cancellation noise signal into sound waves with a phase opposite to that of the primary signal.

[0083] In this embodiment, the secondary speaker 52 is used as the sound generating unit, which mainly converts the cancellation noise signal generated by the controller into sound waves with a phase opposite to that of the primary signal. The Guanyin CAD653 type speaker 52 is selected. At the same time, in order to reduce the interference between the back sound waves and the front sound waves and achieve better sound effects, the speaker 52 is subjected to a cabinet enclosure treatment.

[0084] In a complete set of devices, the signal processing module 4, the signal acquisition module 3, the electret microphone main body 32, and the battery compartment 2 are enclosed in a rectangular box with dimensions not exceeding 400*200*150. The device only needs to expose the speaker 52, the electret microphone extension head 108, the overall battery switch, and the charging port 22.

[0085] As Figures 7 to 9 shown: In terms of in-vehicle testing, a domestic commercial vehicle is used as the test object. This type of commercial vehicle is equipped with a 6-cylinder engine and is a heavy-duty truck. It is also equipped with a high-precision IEPE type sound pressure sensor, a mobile high-performance high-precision multi-channel data acquisition system, a computer, etc. After collecting a large amount of noise and obtaining its noise frequency spectra under various working conditions as Figure 9 shown, it can be found that the noise energy is mainly concentrated in three orders: the 3rd order, the 4.5th order, and the 6th order. Therefore, simultaneously controlling these three orders of 3, 4.5, and 6 can achieve the best noise reduction effect inside the vehicle.

[0086] In terms of noise compensation, the real vehicle test introduced the Zwicker psychoacoustic annoyance model, which integrates psychoacoustic parameters such as loudness, sharpness, roughness, and fluctuation to construct a comprehensive and objective sound quality evaluation system. Through the comprehensive evaluation system and real vehicle test, it can be found that compensating the 4th-order noise and 8.2nd-order noise can maximize the improvement of the in-vehicle sound quality. Figure 10 and Figure 11 It reflects the changes in the in-vehicle sound quality before and after compensating the 4th-order and 8.2nd-order noise under various working conditions on the driver's side and the co-driver's side.

[0087] Beneficial effects

[0088] 1. The overall device is miniaturized, with a relatively simple structure and is very convenient to use.

[0089] 2. In addition to reducing the in-vehicle noise sound pressure level, it can also compensate for noise and improve the overall in-vehicle sound quality.

[0090] The above-disclosed is only a preferred embodiment of a device for suppressing and compensating noise in a vehicle cab of the present invention. Of course, it cannot be used to limit the scope of the rights of the present invention. Those of ordinary skill in the art can understand all or part of the processes of implementing the above embodiments, and the equivalent changes made according to the claims of the present invention still fall within the scope covered by the invention.

Claims

1. A device for suppressing and compensating noise in a vehicle cab, characterized in that it includes a sealed box, a battery compartment, a signal acquisition module, a signal processing module, and a signal output module; the battery compartment is installed in the sealed box and connected to the signal acquisition module, and the signal acquisition module, the signal processing module, and the signal output module are connected in sequence and all installed in the sealed box; the sealed box is used to install the battery compartment, the signal acquisition module, the signal processing module, and the signal output module; the battery compartment is used to supply power to the overall device; the signal acquisition module is used to acquire the engine speed signal and the noise signal in the cab; the signal processing module is used to process and analyze the acquired signals, and generate a cancellation noise signal with a phase opposite to that of the noise, the same frequency and amplitude, and an enhancement signal for compensating the noise; the signal output module is used to output the cancellation noise signal and the enhancement signal.

2. The device for suppressing and compensating noise in a vehicle cab according to claim 1, characterized in that the signal acquisition module includes a microphone drive circuit, an electret microphone body, an engine speed sensor, and an audio power amplifier circuit; the microphone drive circuit is connected to the electret microphone body; the microphone drive circuit is used to drive the microphone to work; the electret microphone body is used to acquire the noise signal in the cab; the engine speed sensor is used to acquire the engine speed signal; the audio power amplifier circuit is used to amplify the acquired noise signal.

3. The device for suppressing and compensating noise in a vehicle cab according to claim 1, characterized in that the signal processing module includes an engine speed acquisition unit, a microcontroller, and an audio decoding unit, and the engine speed acquisition unit, the microcontroller, and the audio decoding unit are connected in sequence. the engine speed acquisition unit is used to acquire the engine speed signal and transmit it to the microcontroller through CAN communication; the microcontroller is used for the operation of the noise equalization control algorithm; the audio decoding unit is used to decode the acquired audio signal.

4. The device for suppressing and compensating noise in a vehicle cab according to claim 1, characterized in that the signal output module includes a power amplifier and a speaker, and the power amplifier is connected to the speaker; the power amplifier is used to amplify the processed noise signal and output it to the speaker; the speaker is used to convert the cancellation noise signal into a sound wave with a phase opposite to that of the primary signal.

5. The device for suppressing and compensating noise in a vehicle cab according to claim 3, characterized in that the microcontroller uses ADSP-21489, the audio decoding unit uses AD1939 chip, and the engine speed acquisition unit uses STM32F407 chip.

Images