Noise control method, device, system and program product

Abstract

The invention relates to a noise control method, device and system and a program product, and relates to the technical field of noise reduction. The noise control method comprises the following steps: determining a second original noise signal of a target position according to a first original noise signal of a sound receiving position of the mechanical equipment and a first signal transfer function between the sound receiving position and the target position of the mechanical equipment; determining an error noise signal of the target position according to the second original noise signal of the target position and the noise control signal of the target position; according to the error noise signal of the target position, the coefficient of a noise reduction filter is updated until the error noise signal of the target position is zero, and the noise reduction filter is used for generating a noise control signal, corresponding to a source noise signal, of a sound loudspeaker position of the mechanical equipment according to the source noise signal of the mechanical equipment.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of noise reduction technology, and in particular, to a noise control method, device, system and program product. BACKGROUND

[0002] With the development of mechanical equipment, various types of mechanical equipment have appeared on the market. Meanwhile, as the working environment of mechanical equipment becomes more diversified, the comfort of the operating personnel during the operation of mechanical equipment is increasingly valued. Among them, the noise problem in the cab of the mechanical equipment has become a key factor for comfort. SUMMARY

[0003] One of the technical problems to be solved by the present disclosure is how to realize adaptive adjustment of the noise control process of the mechanical equipment and guarantee the noise reduction accuracy of the noise control process.

[0004] According to some embodiments of the first aspect of the present disclosure, a noise control method is provided, comprising: determining a second original noise signal of a target position according to a first original noise signal of a sound receiving position of a mechanical equipment and a first signal transfer function between the sound receiving position and the target position; determining an error noise signal of the target position according to the second original noise signal of the target position and a noise control signal of the target position; updating a coefficient of a noise reduction filter according to the error noise signal of the target position until the error noise signal of the target position is zero, wherein the noise reduction filter is used to generate a noise control signal corresponding to a source noise signal of the mechanical equipment at a sound output position of the mechanical equipment according to the source noise signal of the mechanical equipment.

[0005] In some embodiments, before determining the second original noise signal of the target position, the noise control method further comprises: monitoring a first original noise training signal of the sound receiving position and a second original noise training signal of the target position in real time; performing delay processing on the first original noise training signal to obtain a delayed first original noise training signal; and determining the first signal transfer function according to the delayed first original noise training signal and the second original noise training signal.

[0006] In some embodiments, the delay processing on the first original noise training signal to obtain the delayed first original noise training signal comprises: determining the first original noise training signal at a first time as the first original noise training signal at a second time to obtain the delayed first original noise training signal, wherein the first time is earlier than the second time.

[0007] In some embodiments, the delaying the first original noise training signal to obtain the delayed first original noise training signal further comprises: in a case that the first time is an initial time, determining the first original noise signal between the first time and the second time as a zero signal after determining the first original noise training signal at the first time as the first original noise training signal at the second time.

[0008] In some embodiments, the determining the error noise signal at the target position according to the second original noise signal at the target position and the noise control signal at the target position comprises: determining the noise control signal at the target position according to the noise control signal at the sound emitting position of the mechanical equipment and a second signal transfer function between the sound emitting position and the target position; and determining the error noise signal at the target position according to a sum of the second original noise signal at the target position and the noise control signal at the target position.

[0009] In some embodiments, the determining the error noise signal at the target position according to the second original noise signal at the target position and the noise control signal at the target position further comprises: obtaining a source noise signal of the mechanical equipment; and inputting the source noise signal into a noise reduction filter to determine the noise control signal at the sound emitting position.

[0010] In some embodiments, the determining the second original noise signal at the target position according to the first original noise signal at the sound receiving position of the mechanical equipment and a first signal transfer function between the sound receiving position and the target position comprises: obtaining an actual noise signal at the sound receiving position; determining the first original noise signal at the sound receiving position according to a difference between a noise control signal at the sound receiving position and the actual noise signal at the sound receiving position; and determining the second original noise signal at the target position according to the first original noise signal at the sound receiving position and the first signal transfer function.

[0011] In some embodiments, the determining the second original noise signal at the target position according to the first original noise signal at the sound receiving position of the mechanical equipment and a first signal transfer function between the sound receiving position and the target position further comprises: obtaining a noise control signal at a sound emitting position; and determining the noise control signal at the sound receiving position according to the noise control signal at the sound emitting position and a third signal transfer function between the sound emitting position and the sound receiving position.

[0012] In some embodiments, the updating the coefficient of the noise reduction filter according to the error noise signal at the target position comprises: determining a next-time coefficient of the noise reduction filter according to the error noise signal at a current time at the target position and a current-time coefficient of the noise reduction filter; and updating the coefficient of the noise reduction filter according to the next-time coefficient of the noise reduction filter.

[0013] In some embodiments, determining the first signal transfer function according to the time-delayed first original noise training signal and the time-delayed second original noise training signal comprises: determining a cross-spectral density matrix between the time-delayed first original noise training signal and the time-delayed second original noise training signal according to the time-delayed first original noise training signal and the time-delayed second original noise training signal; and determining the first signal transfer function according to the cross-spectral density matrix, a power spectral density matrix of the time-delayed first original noise training signal, and a stability factor.

[0014] In some embodiments, the sound receiving position is one or more, the sound playing-out position is one or more, and the target position is one or more.

[0015] In some embodiments, the time difference between the second time and the first time is a preset threshold.

[0016] According to some embodiments of the second aspect of the present disclosure, a noise control device is provided, comprising: a first determining unit configured to determine a second original noise signal of a target position according to a first original noise signal of a sound receiving position of a mechanical device and a first signal transfer function between the sound receiving position and the target position of the mechanical device; a second determining unit configured to determine an error noise signal of the target position according to the second original noise signal of the target position and a noise control signal of the target position; and an updating unit configured to update a coefficient of a noise reduction filter according to the error noise signal of the target position until the error noise signal of the target position is zero, wherein the noise reduction filter is used to generate a noise control signal corresponding to a source noise signal of the mechanical device at a sound playing-out position of the mechanical device according to the source noise signal of the mechanical device.

[0017] According to some embodiments of the third aspect of the present disclosure, a noise control device is provided, comprising: a memory and a processor coupled to the memory, the processor being configured to execute a noise control method in any of the above embodiments based on instructions stored in the memory.

[0018] According to some embodiments of the fourth aspect of the present disclosure, a noise control system is provided, comprising: the noise control device in any of the above embodiments; and a noise reduction filter configured to receive a source noise signal of a mechanical device sent by the noise control device and generate a noise control signal corresponding to the source noise signal at a sound playing-out position.

[0019] In some embodiments, the noise control system further comprises: a sound playing-out device configured to receive and play out the noise control signal.

[0020] According to some embodiments of the fifth aspect of the present disclosure, a computer readable storage medium is provided, having computer instructions stored thereon, the instructions being executed by a processor to implement the noise control method in any of the above embodiments.

[0021] According to some embodiments of the sixth aspect of the present disclosure, a computer program product is provided, comprising computer instructions which, when executed by a processor, implement the noise control method in any of the above embodiments.

[0022] In the above embodiments, the relationship between the first original noise signal at the sound receiving position and the second original noise signal at the target position can be determined according to the first signal transfer function, which to some extent overcomes the limitations of the sound receiving position determination, reduces the influence of the sound receiving position on the noise reduction effect, enables quick selection of the sound receiving position, reduces the simulation cost, reduces the development cost, improves the efficiency of the noise control process, and enables more accurate estimation and prediction of the second original noise signal at the target position (i.e., the noise signal at the target position). By using the second original noise signal at the target position and the noise control signal at the target position, the error noise signal at the target position is determined, and the coefficients of the noise reduction filter are updated according to the error noise signal (or the characteristics of the noise in the feedback path), which realizes adaptive adjustment of the noise control process of the mechanical equipment, enables timely adjustment of the coefficients of the noise reduction filter according to the error noise signal to adapt to changes in the environment and the target position, and ensures the stability and accuracy of the noise control process of the mechanical equipment. By realizing adaptive adjustment of the noise control process of the mechanical equipment and ensuring the accuracy and stability of the noise control process, the noise level inside the cab of the mechanical equipment is reduced, and the experience and ride comfort of the operator or passenger of the mechanical equipment are significantly improved. In addition, the existing sound receiving device and sound externalizing device of the mechanical equipment are fully utilized, without the need for additional special hardware, which reduces the risk of increasing the manufacturing cost of the mechanical equipment and also reduces the risk of increasing the weight of the mechanical equipment, and better meets the development demands of the mechanical equipment industry (i.e., lightweight and low energy consumption). Furthermore, the noise control method directly processes the source noise signal through the noise reduction filter, which can be applied to noise reduction of noise at various frequencies, and can make up for the limitations of passive noise control in low-frequency noise reduction. BRIEF DESCRIPTION OF DRAWINGS

[0023] The accompanying drawings, which form a part of the specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0024] The present disclosure can be understood more readily by reference to the following detailed description, when taken in connection with the accompanying drawings, and wherein:

[0025] Figure 1 Schematic diagrams showing some embodiments of the noise control method of the present disclosure.

[0026] Figure 2 Schematic diagrams showing some embodiments of the simulation noise reduction results of the noise control method without delay under normal noise reduction of the present disclosure.

[0027] Figure 3 A schematic diagram showing some embodiments of the simulated noise reduction result of the noise control method under divergence noise reduction without time delay of the present disclosure.

[0028] Figure 4 A schematic diagram showing some embodiments of the comparison between the determined value and the measured value of the time domain signal of the second original noise signal of the target position of the present disclosure.

[0029] Figure 5 A schematic diagram showing some embodiments of the comparison between the determined value and the measured value of the frequency domain signal of the second original noise signal of the target position of the present disclosure.

[0030] Figure 6 A schematic diagram showing some embodiments of the cross-correlation coefficient between the first original noise training signal and the second original noise training signal of the present disclosure.

[0031] Figure 7 A schematic diagram showing some embodiments of the simulated noise reduction result of the noise control method under divergence noise reduction with time delay of the present disclosure.

[0032] Figure 8 A schematic diagram showing some embodiments of the measured noise reduction result of the noise control method under divergence noise reduction with time delay of the present disclosure.

[0033] Figure 9 A schematic diagram showing some embodiments of the noise control device of the present disclosure.

[0034] Figure 10 A schematic diagram showing some other embodiments of the noise control device of the present disclosure.

[0035] Figure 11 A schematic diagram showing some embodiments of the noise control system of the present disclosure. DETAILED DESCRIPTION

[0036] Various exemplary embodiments of the present disclosure will now be described in detail by referring to the drawings. It should be noted that the relative arrangement, numerical expressions, and values of the components and steps set forth in these embodiments do not limit the scope of the present disclosure unless specifically stated otherwise.

[0037] At the same time, it should be understood that the sizes of the various parts shown in the drawings are not drawn in accordance with the actual proportional relationship for the convenience of description.

[0038] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way limiting of the disclosure, its application or uses.

[0039] Techniques, methods, and apparatus known to those of ordinary skill in the relevant art(s) can not be discussed in detail in this document, but should be considered as part of the specification.

[0040] In all of the examples shown and discussed herein, any specific values should be interpreted as merely exemplary, and not as a limitation. Thus, other examples of the exemplary embodiments can have different values.

[0041] It should be noted that like reference numerals and letters in the various figures indicate like elements, and thus, discussions of some items in one figure can also apply to like items in another figure.

[0042] During the operation process of the mechanical equipment (for example, when the working vehicle is working), the roar of the engine of the mechanical equipment, the high-frequency whistling of the hydraulic system of the mechanical equipment, and the vibration noise generated by the contact between the mechanical equipment and the ground are all transmitted into the cab of the mechanical equipment. The operator of the mechanical equipment is in such a high-noise environment for a long time, which not only makes the operator feel annoyed and tired, reduces work efficiency, and even causes hearing loss of the operator in severe cases. In addition, during the operation process of the mechanical equipment, excessive noise can mask the abnormal sound during the operation of the mechanical equipment, making it difficult for the operator to detect potential faults of the mechanical equipment, which poses a great safety risk.

[0043] In the related art, the noise control of the mechanical equipment mainly includes two control methods, one is passive noise control (PNC, Passive Noise Control), and the other is active noise control. As for passive noise control, it is a relatively mature technology, and the cost of passive noise control is relatively low, such as laying sound-absorbing and sound-insulating materials or using vibration isolators, etc. However, because low-frequency noise often has the characteristics of long wavelength, long propagation distance, and strong penetration, the absorption and isolation effect of traditional acoustic wrapping materials is limited, so passive noise control has certain limitations in low-frequency noise reduction. Moreover, laying a large amount of acoustic wrapping materials inside the mechanical equipment and installing various vibration isolation devices will inevitably increase the additional weight of the mechanical equipment. However, in the context of pursuing lightweight of the mechanical equipment to improve fuel efficiency, reduce energy consumption, and improve maneuverability, passive noise control has certain limitations in lightweight.

[0044] As for active noise control, its core principle is based on the principle of acoustic destructive interference. Through the control system in the cab of the mechanical equipment, the noise control signal (also known as anti-noise) with equal amplitude and opposite phase to the noise is accurately calculated and played. Through the mutual superposition and cancellation of noise and noise control signal, the effect of noise reduction is achieved.

[0045] The current active noise control (ANC) mainly relies on a noise microphone to collect and process a noise signal, and then the arrangement position of the noise microphone in the cab of the mechanical equipment plays a decisive role in the final noise reduction effect, wherein the noise microphone refers to a device for obtaining a noise signal at the position of the noise microphone. Considering that the internal space acoustic environment of the cab of the mechanical equipment is relatively complex, sound propagation will be affected by reflection, scattering and the like of many articles such as seats, interiors and the like. Because once the position of the noise microphone is far away from the position of the human ear of the operator, there will be a large deviation between the noise signal collected by the noise microphone and the noise signal actually heard by the operator, and if the noise control signal with opposite phase is generated based on the noise signal with deviation, the final noise reduction effect will be greatly reduced, and even a worse situation of greater noise may occur, for example, the noise detected at the noise microphone is reduced, but the actual noise at the human ear is increased.

[0046] However, in addition to the influence of the position of the noise microphone on the noise reduction effect, the effective range of the active noise control in space is small, and generally only a sphere with the noise microphone as the center and the tenth of the wavelength corresponding to the noise frequency as the radius can obviously perceive the noise reduction effect, so if the noise microphone is far away from the human ear, the effective noise reduction effect cannot be achieved, and the actual demand for improving the work comfort of the operator cannot be met.

[0047] Therefore, how to realize adaptive adjustment of the noise control process of the mechanical equipment and guarantee the noise reduction accuracy of the noise control process is a problem to be solved. In order to solve the problem of how to realize adaptive adjustment of the noise control process of the mechanical equipment and guarantee the noise reduction accuracy of the noise control process, the present disclosure proposes a noise control method, which is specifically as follows.

[0048] Figure 1 A schematic diagram showing some embodiments of the noise control method of the present disclosure.

[0049] As Figure 1 shown, the noise control method includes steps 110 to 130, and the noise control method is executed by a noise control device.

[0050] In step 110, a second original noise signal of a target position is determined according to a first original noise signal of the target position and a first signal transfer function between the target position and a target position of the mechanical equipment.

[0051] For example, the sound receiving position in the mechanical equipment can be one or more, and the sound receiving device corresponding to the sound receiving position in the mechanical equipment can be a sound receiving microphone.

[0052] For example, the first original noise signal is detected by a sound receiving device at a sound receiving position of the mechanical equipment, and the sound receiving device can be a microphone (also referred to as a monitoring microphone).

[0053] In step 120, an error noise signal of the target position is determined according to the second original noise signal of the target position and a noise control signal of the target position.

[0054] For example, the noise control signal of the target position refers to a signal used to cancel out the source noise signal at the target position, and the phase of the noise control signal and the source noise signal is as opposite as possible, and the amplitude is as equal as possible.

[0055] In step 130, the coefficients of the noise reduction filter are updated according to the error noise signal of the target position until the error noise signal of the target position is zero, wherein the noise reduction filter is used to generate a noise control signal corresponding to the source noise signal at a sound output position of the mechanical equipment according to the source noise signal of the mechanical equipment.

[0056] By updating the coefficients of the noise reduction filter, the noise reduction filter can generate a noise control signal that cancels out the source noise signal as much as possible. For example, the source noise signal can be at least one of the roar of the engine, the high-frequency whistling of the hydraulic system, and the vibration noise generated by the mechanical equipment in contact with the ground.

[0057] The error noise signal of the target position being zero means that the second original noise signal of the target position and the noise control signal of the target position are signals with opposite phases and the same amplitudes, i.e., the noise control signal of the target position can completely cancel out the second original noise signal of the target position.

[0058] For example, the sound output position of the mechanical equipment can be one or more, and the sound output position can be the position of a loudspeaker in the mechanical equipment. For example, the noise reduction filter can be a filter with multiple inputs and multiple outputs, and noise control can be achieved by a feedforward adaptive algorithm (for example, a filter x least mean square algorithm).

[0059] Through the cooperation of multiple sound output devices and multiple sound receiving devices, the noise reduction effect of the noise control method is improved, and in addition, the noise is reduced by a multi-channel noise reduction filter, which reduces the computational complexity of the noise control method and improves the efficiency of noise control.

[0060] The noise control signal corresponding to the source noise signal at the sound emitting position of the mechanical equipment is generated by the noise reduction filter, if the noise reduction filter is a single-channel filter, the process is shown in formula (1), if the noise reduction filter is a multi-channel filter, the input signal and the output signal of each channel are coupled with each other, the process is shown in formula (2).

[0061] (1)

[0062] Wherein, x(n) is the source noise signal, x(n-i) is the source noise signal at n-i time, y(n) is the noise control signal at the sound emitting position, w i (n) is the coefficient of the noise reduction filter, L represents the length of the noise reduction filter (that is, the noise reduction filter takes the nearest L sampling points of the source noise signal at each sampling time), i represents the index of the L sampling points, and n is the time sequence number of the source noise signal.

[0063] (2)

[0064] Wherein, is the noise control signal at the sound emitting position of the source noise signal output by the dth channel of the noise reduction filter, the value range of d is 1 to D, and there are D noise control signals in total, is the mth source noise signal, is the mth source noise signal at n-i time, the value range of m is 1 to M, and there are M source noise signals in total, is the coefficient of the noise reduction filter of the mth source noise signal corresponding to the ith sampling point to the dth noise control signal channel, the filter coefficient here is a matrix, which can be a square matrix or not, and each noise control signal channel corresponds to a noise control signal.

[0065] In the above embodiment, the relationship between the first original noise signal of the sound receiving position and the second original noise signal of the target position can be determined according to the first signal transfer function, which to some extent overcomes the limitations of the sound receiving position determination, reduces the influence of the sound receiving position on the noise reduction effect, can quickly select the sound receiving position, reduces the simulation cost, reduces the development cost, improves the efficiency of the noise control process, and can more accurately estimate and predict the second original noise signal of the target position (i.e., the noise signal at the target position). By the second original noise signal of the target position and the noise control signal of the target position, the error noise signal of the target position is determined, and the coefficients of the noise reduction filter are updated according to the error noise signal (or the characteristics of the noise in the feedback path), which realizes the adaptive adjustment of the noise control process of the mechanical equipment, can adjust the coefficients of the noise reduction filter in time according to the error noise signal to adapt to the changes of the environment and the target position, and ensures the stability and accuracy of the noise control process of the mechanical equipment. By realizing the adaptive adjustment of the noise control process of the mechanical equipment and ensuring the accuracy and stability of the noise control process, the noise level inside the cab of the mechanical equipment is reduced, and the experience and riding comfort of the operator or passenger of the mechanical equipment are significantly improved. In addition, the existing sound receiving device and sound external device of the mechanical equipment are fully utilized, without the need for additional special hardware, which reduces the risk of increasing the manufacturing cost of the mechanical equipment and also reduces the risk of increasing the weight of the mechanical equipment, and can better meet the development demands of the mechanical equipment industry (i.e., lightweight and low energy consumption). In addition, the noise control method directly processes the source noise signal through the noise reduction filter, which can be applied to noise reduction of each frequency, and can make up for the limitations of passive noise control in low-frequency noise reduction. By making up for the limitations of passive noise control in low-frequency noise reduction, the common low-frequency engine noise and hydraulic system noise in the mechanical equipment can be effectively suppressed.

[0066] In addition, the noise control method can adaptively adjust the coefficients of the noise reduction filter in real time to make the noise reduction filter generate a more appropriate noise control signal, so that the noise control method can be applied to various different working conditions and noise environments, and has strong adaptability and practicality.

[0067] The noise control method guarantees the accuracy of the second original noise signal of the determined target position, the noise control signal of the target position, and the noise control signal of the receiving position by introducing a secondary path (i.e., a first signal transfer function). In addition, the noise control method realizes adaptive adjustment by introducing a feedback path (i.e., updating the coefficients of the noise reduction filter according to the error noise signal of the target position). However, the feedback path causes delay, phase shift, and other interference, which affects the stability and convergence speed of the noise control method. Therefore, by introducing a noise reduction filter, the influence of such interference can be compensated for, thereby optimizing the noise control signal and guaranteeing effective noise control.

[0068] The following describes how the first signal transfer function is determined in combination with the following embodiments.

[0069] In some embodiments, the first signal transfer function is determined according to the first original noise training signal of the receiving position after time delay processing and the second original noise training signal of the target position.

[0070] In some embodiments, the first original noise training signal of the receiving position and the second original noise training signal of the target position are monitored in real time before the second original noise signal of the target position is determined; the first original noise training signal is processed by time delay to obtain a time-delayed first original noise training signal; and the first signal transfer function is determined according to the time-delayed first original noise training signal and the second original noise training signal.

[0071] For example, the first original noise training signal of the receiving position and the second original noise training signal of the target position are monitored in real time by a receiving device (e.g., a microphone). Specifically, two receiving devices can be installed at the receiving position and the target position to facilitate real-time monitoring of the first original noise training signal of the receiving position and the second original noise training signal of the target position by the receiving device.

[0072] Regarding time delay processing, in some embodiments, the first original noise training signal at a first time is determined as the first original noise training signal at a second time to obtain a time-delayed first original noise training signal, where the first time is earlier than the second time.

[0073] For example, the time difference between the second time and the first time is a preset threshold. For example, the preset threshold can be 10 time points.

[0074] By determining the first original noise training signal at the first time of the sound receiving position as the first original noise training signal at the second time of the sound receiving position, the first time being earlier than the second time, the delay processing of the first original noise signal is realized, the causality between the first original noise signal and the second original noise signal is met, that is, the first original noise signal at a certain time is earlier than the second original noise signal at the time, because the sound receiving position is located at the "upstream" position of the target position (or both are co-located), the risk of divergence noise reduction caused by the non-causality between the first original noise signal and the second original noise signal is reduced, and the accuracy and stability of the noise control process of the mechanical equipment are ensured.

[0075] In addition, by adjusting the time sequence of the first original noise signal at the sound receiving position, the possibility of divergence noise reduction is reduced, the time cost of finding the reason of divergence noise reduction problem is reduced, the time cost of the noise control process is reduced, and the efficiency of noise control is improved.

[0076] In some embodiments, after determining the first original noise training signal at the first time as the first original noise training signal at the second time, in the case that the first time is the initial time, the first original noise signal between the first time and the second time is determined as a zero signal.

[0077] By determining the first original noise signal between the first time and the second time as a zero signal, in the process of determining the first signal transfer function, the interference of the first original noise signal between the first time and the second time after delay to the first signal transfer function is reduced, and the accuracy of the first signal transfer function is ensured.

[0078] Regarding how to determine the first signal transfer function according to the delayed first original noise training signal and the second original noise signal, in some embodiments, the cross-spectral density matrix between the delayed first original noise training signal and the second original noise training signal is determined according to the delayed first original noise training signal and the second original noise training signal; the first signal transfer function is determined according to the cross-spectral density matrix, the power spectral density matrix of the delayed first original noise training signal and the stability factor.

[0079] Regarding the determination of the first signal transfer function, it can be determined by formula (3) and inverse Fourier transform of formula (3).

[0080] (3)

[0081] Wherein, f represents the frequency sequence number, is the cross-spectral density matrix between the delayed first original noise training signal and the second original noise training signal, is a power spectral density matrix between the second original noise training signals, I is an identity matrix, and the size of the identity matrix is consistent with , is a stability factor, used to suppress numerical stability problems caused by inversion of the ,

[0082] The specific determination method of the error noise signal of the target position is described in combination with the following embodiments, and is specifically as follows.

[0083] In some embodiments, the noise control signal of the target position is determined according to the noise control signal of the sound emitting position of the mechanical equipment and the second signal transfer function between the sound emitting position and the target position; and the error noise signal of the target position is determined according to the sum of the second original noise signal of the target position and the noise control signal of the target position.

[0084] The noise control signal of the target position is determined through the noise control signal of the sound emitting position and the second signal transfer function, and the error noise signal of the target position is determined according to the sum of the noise control signal of the target position and the second original noise signal of the target position (the error noise signal is determined through the sum because the second original noise signal and the noise control signal are signals with opposite phases), which can obtain an accurate noise control signal of the target position, thereby obtaining an accurate error noise signal of the target position, so as to update the coefficients of the noise reduction filter according to the error noise signal of the target position in the subsequent process, improve the accuracy of the noise control signal generated by the noise reduction filter, and ensure the stability and accuracy of the noise control process.

[0085] Regarding the noise control signal of the sound emitting position, in some embodiments, a source noise signal of the mechanical equipment is obtained; the source noise signal is input into a noise reduction filter to determine the noise control signal of the sound emitting position.

[0086] The error noise signal of the target position is determined according to the second original noise signal of the target position and the noise control signal of the target position, as shown in formula (4) or formula (5).

[0087] (4)

[0088] wherein, is the error noise signal of the pth target position at the n time, is the second original noise signal of the pth target position at the n time, is the noise control signal of the target position, is the noise control signal of the qth sound emitting position at the n time, The second signal transfer function, i.e., the second signal transfer function from the qth sound playing position (or sound playing device) to the pth target position, can also be referred to as a sound playing position to target position impulse response (or a secondary path transfer function), and is used to describe the complete physical process of the noise control signal being played (or played out) and propagating in space (from the sound playing position to the target position), represents a convolution operation, and Q represents the number of noise control signals, and can also represent the number of sound playing positions.

[0089] (5)

[0090] wherein, represents an error noise signal of the target position, represents a second original noise signal (which can also be referred to as a fluctuation signal of the source noise signal at the target position) of the target position, represents a noise control signal of the target position, represents a noise control signal of the sound playing position, represents a second signal transfer function (which can also be referred to as a secondary path transfer function between the noise control signal of the sound playing position and the noise control signal of the target position), and formula (5) omits the time index.

[0091] The specific determination method of the second original noise signal of the target position is described in combination with the following embodiments, and is as follows.

[0092] In some embodiments, an actual noise signal of the sound receiving position is obtained; a first original noise signal of the sound receiving position is determined according to a difference between the noise control signal of the sound receiving position and the actual noise signal of the sound receiving position; and a second original noise signal of the target position is determined according to the first original noise signal of the sound receiving position and the first signal transfer function.

[0093] In the determination of the first original noise signal of the sound receiving position, the influence of the noise control signal of the sound receiving position on the actual noise signal of the sound receiving position is considered, the accuracy of the determined first original noise signal of the sound receiving position is improved, and thus the accuracy of the determined second original noise signal of the target position is improved, which helps to ensure the accuracy of the noise control process.

[0094] Regarding the noise control signal of the sound receiving position, in some embodiments, a noise control signal of a sound playing position is obtained; and the noise control signal of the sound receiving position is determined according to the noise control signal of the sound playing position and a third signal transfer function between the sound playing position and the sound receiving position.

[0095] In the determination of the noise control signal at the sound receiving position, the loss of sound propagation from the sound emitting position to the sound receiving position is considered, and an accurate noise control signal at the sound receiving position can be obtained.

[0096] The determination of the second original noise signal at the target position is shown in formula (6) and formula (7).

[0097] (6)

[0098] (7)

[0099] In formula (6), denotes the actual noise signal at the sound receiving position, denotes the first original noise signal at the sound receiving position (also referred to as the fluctuation signal of the source noise signal at the sound receiving position), denotes the noise control signal at the sound receiving position, denotes the noise control signal at the sound emitting position, denotes the third signal transfer function between the sound emitting position and the sound receiving position (also referred to as the secondary path transfer function between the noise control signal at the sound emitting position and the noise control signal at the sound receiving position), and formula (6) omits the time index. In formula (7), denotes the convolution operation, denotes the first signal transfer function (also referred to as the observation filter), and the mapping relationship between the first original noise signal at the sound receiving position and the second original noise signal at the target position is established through the observation filter, so as to subsequently determine the second original noise signal at the target position according to the first original noise signal at the sound receiving position and the first signal transfer function.

[0100] The specific steps of updating the coefficients of the noise reduction filter are described in combination with the following embodiments.

[0101] In some embodiments, the coefficients of the noise reduction filter at the next time are determined according to the error noise signal at the current time of the target position and the coefficients of the noise reduction filter at the current time; and the coefficients of the noise reduction filter are updated according to the coefficients of the noise reduction filter at the next time.

[0102] The coefficients of the noise reduction filter are updated, as shown in formula (8) or formula (9).

[0103] (8)

[0104] wherein, is the coefficient of the noise reduction filter of the mth source noise signal to the noise control signal channel of the dth noise control signal at the next time (n+1 time), is a coefficient of a noise reduction filter for a current moment (n moment) of the mth source noise signal to the dth noise control signal channel, is a step factor for determining an updating speed of the coefficient of the noise reduction filter, is an error noise signal of a target position for a current moment, is a source noise signal of the mth source noise signal to the dth noise control signal channel after forward filtering for a current moment, for considering an influence of a secondary path on noise control.

[0105] (9)

[0106] wherein, is a coefficient of a noise reduction filter for a next moment (n+1 moment), is a coefficient of a noise reduction filter for a current moment (n moment), is a step factor, is an error noise signal of a target position for a current moment, is a source noise signal after forward filtering for a current moment, and n represents a time sequence number.

[0107] The noise control method mainly includes two parts, a development part and a debugging part. In the development part, a first original noise training signal of a sound receiving position and a second original noise training signal of a target position are detected by a sound receiving device, and the first original noise training signal is processed by time delay. A first signal transfer function is determined according to the first original noise training signal after time delay and the second original noise training signal. In the debugging part, a second original noise signal of the target position is determined according to the first original noise signal of the sound receiving position and the first signal transfer function determined in the development part. An error noise signal of the target position is determined according to the second original noise signal of the target position and a noise control signal of the target position. The coefficient of the noise reduction filter is updated by the error noise signal of the target position, so that the error noise signal of the target position is zero. At the same time, the noise control signal corresponding to the source noise signal is generated by the noise reduction filter, so as to offset the source noise signal as much as possible and realize noise reduction.

[0108] The noise reduction effect of the noise control method will be described below in combination with Figures 2 to 8 , which assumes that the mechanical equipment is a working vehicle, an artificial head is placed at a seat of the working vehicle, and five sound receiving positions (i.e. monitoring microphone positions) are arranged at positions such as an operating handle, a ceiling and a seat back of the working vehicle. Meanwhile, it is assumed that the cab also includes a plurality of sound emitting positions (i.e. loudspeaker positions), wherein a sound emitting device at the sound emitting position is used to play a noise control signal, and the specific implementation is as follows.

[0109] Figure 2Figures showing simulation results of the noise control method of the present disclosure without time delay under normal noise reduction. In the figures, the step factor in the process of updating the coefficients of the noise reduction filter is 1, and the target positions are two, which are the left ear position and the right ear position of the artificial head, respectively.

[0110] Figure 2 (a) in the figures is the noise spectrum before and after noise reduction at the left ear position (target position), Figure 2 (b) in the figures is the noise spectrum before and after noise reduction at the right ear position (target position), Figure 2 The dotted line in (a) and (b) in the figures represents the noise spectrum before noise reduction (i.e., without processing by the noise control method), Figure 2 The solid line with dots in (a) and (b) in the figures represents the noise spectrum after noise reduction (i.e., with processing by the noise control method). Figure 2 The horizontal axis in (a) and (b) in the figures represents frequency in Hz, and the vertical axis represents sound pressure level (SPL) in dB (A). Figure 2 RNC (Road Noise Cancellation) off in (a) and (b) in the figures represents road noise active noise reduction off, and RNC on represents road noise active noise reduction on.

[0111] As shown in Figure 2 , the left ear position and the right ear position have relatively ideal noise reduction effects in the frequency range of 70 Hz to 500 Hz. The noise generated by the working vehicle during operation that belongs to this frequency range is the part that has a greater impact on the operator, so by effectively reducing the noise in this frequency range, the acoustic comfort of the cab of the working vehicle can be significantly improved.

[0112] The noise control system cannot directly analogize the noise reduction effect to other active noise reduction systems (such as noise reduction earphones) due to the existence of the secondary path. The noise reduction amount of the former noise control system is generally a few dB, and the noise reduction amount of the noise reduction earphone is generally a few tens of dB, so Figure 2 , the noise control method can effectively reduce the noise of the mechanical equipment.

[0113] For Figure 2, the target positions are just the left ear position and the right ear position, the noise reduction effect of the noise control method not involving the delay processing is in a stable state (i.e. normal noise reduction), but when the target positions do not change and the left ear position and the right ear position change (for example, the left ear position and the right ear position (or the artificial head) are moved 10 cm forward from the original position, and the original position can be the position close to the headrest), that is, the two target positions are located around the left ear position and the right ear position, in this case, if the noise reduction is performed by the noise control method not involving the delay processing, the noise reduction result will be in a divergent state (i.e. divergent noise reduction), as shown in Figure 3 .

[0114] Figure 3 Some embodiments of the simulation noise reduction result of the noise control method not involving the delay processing under the divergent noise reduction of the present disclosure are shown in the schematic diagram.

[0115] In the simulation noise reduction result shown in Figure 3 , the step factor in the process of updating the coefficients of the noise reduction filter is still 1, and the target positions are two, which are around the left ear position and the right ear position of the artificial head.

[0116] Figure 3 (a) in (a) and (b) in (b) of FIG. 13 is the noise spectrum before and after noise reduction at the left ear position (around the target position), Figure 3 (b) in (a) and (b) of FIG. 13 is the noise spectrum before and after noise reduction at the right ear position (around the target position), Figure 3 the dotted line in (a) and (b) in (a) and (b) of FIG. 13 represents the noise spectrum before noise reduction (i.e. not processed by the noise control method), Figure 3 the dotted line in (a) and (b) in (a) and (b) of FIG. 13 represents the noise spectrum after noise reduction (i.e. processed by the noise control method). Figure 3 the horizontal axis in (a) and (b) in (a) and (b) of FIG. 13 represents the frequency, and the unit is Hz, and the vertical axis represents the sound pressure level (SPL, Sound Pressure Level), and the unit is dB (A). Figure 3 RNC (Road Noise Cancellation, road noise active noise reduction) off in (a) and (b) in (a) and (b) of FIG. 13 represents that the road noise active noise reduction is off, and RNC on represents that the road noise active noise reduction is on.

[0117] As shown in Figure 3 (a) and (b), the noise spectrum after noise reduction is obviously higher than the noise spectrum before noise reduction, that is, the noise after noise reduction is more obvious than the noise before noise reduction, and it can be known that in the case that the environment in the cab of the working vehicle changes slightly (for example, the change of the position of the head of the operator), the normal noise reduction will be seriously affected, the normal noise reduction will become divergent noise reduction, thereby causing the noise reduction failure or the noise to be larger by the noise control method not involving the delay processing.

[0118] In order to determine the cause of the occurrence of the divergent noise reduction, the determined value and the measured value of the time-domain signal of the second original noise signal at the target position are compared first, as shown in Figure 4 and Figure 5 Figure 4 The comparison is of the time-domain signal of the second original noise signal. Figure 5 The comparison is of the frequency-domain signal of the second original noise signal, and the target positions are two, one being around the left ear position and the other being around the right ear position. Figure 4 FIG. 1 shows a schematic diagram of some embodiments of the comparison between the determined value and the measured value of the time-domain signal of the second original noise signal at the target position of the present disclosure, Figure 5 FIG. 2 shows a schematic diagram of some embodiments of the comparison between the determined value and the measured value of the frequency-domain signal of the second original noise signal at the target position of the present disclosure, Figure 4 The time length of the time-domain signal shown in FIG. 1 is 180 seconds.

[0119] Figure 4 The red solid line in (a) and (b) of FIG. 1 represents the determined value (i.e., the estimated value), and the blue solid line represents the measured value. Figure 4 The horizontal axis of (a) and (b) of FIG. 1 represents time (t) in seconds (s), and the vertical axis represents the amplitude of the time-domain signal. Figure 4 (a) of FIG. 1 represents the time-domain signal of the second original noise signal at the target position around the left ear position. Figure 4 (b) of FIG. 1 represents the time-domain signal of the second original noise signal at the target position around the right ear position.

[0120] As shown in Figure 4 (a) and (b) of FIG. 1, the determined value and the measured value of the time-domain signal of the second original noise signal at the target position are highly consistent, i.e., the determination (or estimation) of the second original noise signal at the target position in the time domain is accurate, and the measured value is very close.

[0121] Figure 5 The dotted solid line in (a) and (b) of FIG. 2 represents the determined value (i.e., the estimated value), and the non-dotted solid line represents the measured value. Figure 5 The horizontal axis of (a) and (b) of FIG. 2 represents frequency in Hz, and the vertical axis represents SPL in dB(A). Figure 5 (a) of FIG. 2 represents the frequency-domain signal of the second original noise signal at the target position around the left ear position. Figure 5 (b) of FIG. 2 represents the frequency-domain signal of the second original noise signal at the target position around the right ear position. Figure 5 ​As shown in (a) and (b), taking a sampling time of 10 seconds as an example, the average value of the estimated frequency domain signal of the second original noise signal at the target position around the left ear position is 61.41 dB(A), the average value of the estimated frequency domain signal of the second original noise signal at the target position around the left ear position is 61.28 dB(A), the average value of the estimated frequency domain signal of the second original noise signal at the target position around the right ear position is 58.8 dB(A), and the average value of the measured frequency domain signal of the second original noise signal at the target position around the right ear position is 59.27 dB(A).

[0122] like Figure 5 As shown in (a) and (b), the determined value of the second original noise signal at the target location in the frequency domain is in high agreement with the measured value, which means that the determination (or estimation) of the second original noise signal at the target location in the frequency domain is accurate and very close to the measured value.

[0123] Combination Figure 4 and Figure 5 It is known that even if the target position is not the same as the left or right ear position, the accurate second original noise signal at the target position can be determined based on the first signal transfer function (i.e., the observation filter) without time delay processing and the first original noise signal at the receiving position. However, this does not mean that the first signal transfer function (i.e., the observation filter) accurately reflects the mapping relationship between the first original noise signal at the receiving position and the second original noise signal at the target position. Further calculation of the cross-correlation coefficient between the first original noise signal at the receiving position and the second original noise signal at the target position (e.g., ...) is still required. Figure 6 As shown, the causality between the first original noise signal at the receiving position and the second original noise signal at the target position is determined by the cross-correlation coefficient between them.

[0124] Since the receiving position is located "upstream" of the target position in the noise transmission path (or both are located upstream), the noise control method needs to determine the second original noise signal of the target position through the first original noise signal of the receiving position. That is, the first original noise signal of the receiving position is the "cause" and the second original noise signal of the target position is the "effect". Therefore, the causality between the first original noise signal of the receiving position and the second original noise signal of the target position means that the first original noise signal of the receiving position needs to be earlier than the second original noise signal of the target position.

[0125] Figure 6 Schematic diagrams illustrating some embodiments of the cross-correlation coefficients between the first and second original noise training signals of this disclosure.

[0126] likeFigure 6 The cross-correlation coefficients include C11, C12, C13, C14, C15, C21, C22, C23, C24, and C25, as shown. Figure 6 Taking a mechanical device including two target positions and five sound receiving positions as an example, the two targets are a first target position and a second target position, and the five sound receiving positions are a first sound receiving position, a second sound receiving position, a third sound receiving position, a fourth sound receiving position, and a fifth sound receiving position. C11 represents the cross-correlation number between the second original noise training signal of the first target position and the first original noise training signal of the first sound receiving position, C12 represents the cross-correlation number between the second original noise training signal of the first target position and the first original noise training signal of the second sound receiving position, C13 represents the cross-correlation number between the second original noise training signal of the first target position and the first original noise training signal of the third sound receiving position, C14 represents the cross-correlation number between the second original noise training signal of the first target position and the first original noise training signal of the fourth sound receiving position, C15 represents the cross-correlation number between the second original noise training signal of the first target position and the first original noise training signal of the fifth sound receiving position, C21 represents the cross-correlation number between the second original noise training signal of the second target position and the first original noise training signal of the first sound receiving position, C22 represents the cross-correlation number between the second original noise training signal of the second target position and the first original noise training signal of the second sound receiving position, C23 represents the cross-correlation number between the second original noise training signal of the second target position and the first original noise training signal of the third sound receiving position, C24 represents the cross-correlation number between the second original noise training signal of the second target position and the first original noise training signal of the fourth sound receiving position, and C25 represents the cross-correlation number between the second original noise training signal of the second target position and the first original noise training signal of the fifth sound receiving position. The first original noise training signal is detected by the sound receiving device at the sound receiving position, and the second original noise training signal is detected by the sound receiving device at the target position.

[0127] As Figure 6If the maximum value of the cross-correlation number appears at the zero point or positive half of the abscissa axis, it indicates that the causality between the first original noise training signal and the second original noise training signal is satisfied, however, the maximum values of C12 and C22 both appear on the negative half of the abscissa axis (wherein the abscissa represents the time difference between the second original noise training signal and the first original noise training signal, and the ordinate represents the cross-correlation number between the second original noise training signal and the first original noise training signal), indicating that the second original noise training signal arrives at the target position first, and then the first original noise training signal arrives at the sound receiving position, which violates the causality between the first original noise training signal and the second original noise training signal. However, causality is an important principle to guarantee the noise reduction effect in the noise processing process, and any violation of causality may cause the noise reduction effect to deteriorate.

[0128] In order to meet the requirement of causality between the first original noise training signal and the second original noise training signal, the first original noise training signal is subjected to delay processing to adjust the timing of the first original noise training signal and the second original noise training signal, so as to meet the causality between the first original noise training signal and the second original noise training signal. The first signal transfer function is determined by the first original noise training signal and the second original noise training signal after delay processing, which guarantees the accuracy and stability of the determined first signal transfer function, improves the accuracy and stability of the determined second original noise signal, and thus guarantees the accuracy and stability of the noise control process, reducing the risk of violating causality on the noise reduction effect.

[0129] The second original noise signal at the target position is determined by the first signal transfer function determined after the delay processing of the first original noise training signal, and subsequent noise control is performed. The following explains the noise reduction effect after overcoming the causality problem from simulation and actual measurement.

[0130] Figure 7 Some embodiments of the simulation noise reduction results of the noise control method with delay under the divergent noise reduction of the present disclosure are shown in the schematic diagram. Figure 8 Some embodiments of the actual measurement noise reduction results of the noise control method with delay under the divergent noise reduction of the present disclosure are shown in the schematic diagram. Among them, Figure 7 and Figure 8 There are two target positions of the mechanical equipment, which are the surroundings of the left ear position and the right ear position.

[0131] Figure 7 (a) in (a) is the noise spectrum before and after noise reduction at the left ear position (around the target position), Figure 7 (b) in (b) is the noise spectrum before and after noise reduction at the right ear position (around the target position), Figure 7In (a) and (b), the solid lines without dots represent the noise spectrum before noise reduction (i.e., before noise control methods are applied). Figure 7 In (a) and (b), the dotted solid lines represent the noise spectrum after noise reduction (i.e., after processing by noise control methods). Figure 7 In (a) and (b), the horizontal axis represents frequency in Hz, and the vertical axis represents sound pressure level (SPL) in dB (A).

[0132] like Figure 7 As shown, during the simulation, the second original noise signal at the target position is determined by the first signal transfer function after delaying the first original noise training signal, and subsequent noise control is performed. This ensures the stability of the noise control process and achieves good noise reduction. It can be seen that by overcoming the causality problem through delaying the first original noise training signal, the divergent noise reduction problem can be overcome, ensuring the stability and accuracy of the noise control process. Furthermore, Figure 7 The results also verify that the cause of divergent noise reduction is due to the causal relationship of the training signal timing, and also demonstrate that by adjusting the timing of the first and second original noise training signals, the stability and accuracy of the noise control process can be effectively achieved.

[0133] Based on the simulation, in order to verify the performance of the noise control method in real-world scenarios, actual measurements were conducted based on the noise control method, as detailed below.

[0134] Figure 8 (a) shows the noise spectrum before and after noise reduction at the left ear location (around the target location). Figure 8 (b) shows the noise spectrum before and after noise reduction at the right ear location (around the target location). Figure 8 In (a) and (b), the solid lines without dots represent the noise spectrum before noise reduction (i.e., before noise control methods are applied). Figure 8 In (a) and (b), the dotted solid lines represent the noise spectrum after noise reduction (i.e., after processing by noise control methods). Figure 8 In (a) and (b), the horizontal axis represents frequency in Hz, and the vertical axis represents sound pressure level (SPL) in dB (A).

[0135] like Figure 8As shown, in the actual measurement process, the second original noise signal of the target position is determined by the first signal transfer function determined after the time delay processing of the first original noise training signal, and subsequent noise control is performed, which guarantees the stability of the noise control process and achieves good noise reduction effect. It can be seen that after overcoming the causality problem by time delay processing of the first original noise training signal, the problem of divergence noise reduction can be overcome, which guarantees the stability and accuracy of the noise control process.

[0136] Figure 9 A schematic diagram showing some embodiments of the noise control device of the present disclosure.

[0137] As Figure 9 shown, the noise control device 90 includes a first determination unit 91, a second determination unit 92, and an update unit 93.

[0138] The first determination unit 91 is configured to determine a second original noise signal of a target position according to a first original noise signal of a sound receiving position of a mechanical device and a first signal transfer function between the sound receiving position and the target position of the mechanical device.

[0139] The second determination unit 92 is configured to determine an error noise signal of the target position according to the second original noise signal of the target position and a noise control signal of the target position.

[0140] The update unit 93 is configured to update a coefficient of a noise reduction filter according to the error noise signal of the target position until the error noise signal of the target position is zero, wherein the noise reduction filter is used to generate a noise control signal corresponding to a source noise signal of the mechanical device at a sound playing position of the mechanical device according to the source noise signal of the mechanical device.

[0141] For example, the sound receiving position is one or more, the sound playing position is one or more, and the target position is one or more.

[0142] In the above embodiment, the relationship between the first original noise signal of the sound collecting position and the second original noise signal of the target position can be determined according to the first signal transfer function, which to some extent overcomes the limitation of the sound collecting position determination, reduces the influence of the sound collecting position on the noise reduction effect, enables quick selection of the sound collecting position, reduces the simulation cost, reduces the development cost, improves the efficiency of the noise control process, and more accurately estimates and predicts the second original noise signal of the target position (i.e., the noise signal at the target position). By using the second original noise signal of the target position and the noise control signal of the target position, the error noise signal of the target position is determined, and the coefficients of the noise reduction filter are updated according to the error noise signal (or the characteristics of the noise in the feedback path), which realizes adaptive adjustment of the noise control process of the mechanical equipment, enables timely adjustment of the coefficients of the noise reduction filter according to the error noise signal to adapt to changes in the environment and the target position, and ensures the stability and accuracy of the noise control process of the mechanical equipment. By realizing adaptive adjustment of the noise control process of the mechanical equipment and ensuring the accuracy and stability of the noise control process, the noise level inside the cab of the mechanical equipment is reduced, and the experience and ride comfort of the operator or passenger of the mechanical equipment are significantly improved. In addition, the existing sound collecting device and sound external device of the mechanical equipment are fully utilized, without the need for additional special hardware, which reduces the risk of increasing the manufacturing cost of the mechanical equipment and also reduces the risk of increasing the weight of the mechanical equipment, and better meets the development demands of the mechanical equipment industry (i.e., lightweight and low energy consumption). In addition, the noise control method directly processes the source noise signal through the noise reduction filter, which can be applied to noise reduction of noise at various frequencies, and can make up for the limitations of passive noise control in low-frequency noise reduction.

[0143] In some embodiments, the noise control device 90 further comprises a third determination unit configured to, before determining the second original noise signal of the target position, monitor the first original noise training signal of the sound collecting position and the second original noise training signal of the target position in real time; delay processing the first original noise training signal to obtain a delayed first original noise training signal; and determine the first signal transfer function according to the delayed first original noise training signal and the second original noise training signal.

[0144] In some embodiments, the third determination unit is further configured to determine the first original noise training signal at the first time as the first original noise training signal at the second time to obtain the delayed first original noise training signal, wherein the first time is earlier than the second time.

[0145] In some embodiments, the third determining unit is further configured to, in a case that the first time is an initial time, determine the first original noise signal between the first time and the second time as a zero signal after determining the first original noise signal at the first time as the first original noise signal at the second time.

[0146] In some embodiments, the time difference between the second time and the first time is a preset threshold.

[0147] In some embodiments, the third determining unit is further configured to determine a cross-spectral density matrix between the delayed first original noise signal and the delayed second original noise signal according to the delayed first original noise signal and the delayed second original noise signal; and determine the first signal transfer function according to the cross-spectral density matrix, a power spectral density matrix of the delayed first original noise signal, and a stability factor.

[0148] In some embodiments, the second determining unit 92 is further configured to determine a noise control signal at the target position according to a noise control signal at a sound emitting position of the mechanical equipment and a second signal transfer function between the sound emitting position and the target position; and determine an error noise signal at the target position according to a sum of a second original noise signal at the target position and the noise control signal at the target position.

[0149] In some embodiments, the second determining unit 92 is further configured to obtain a source noise signal of the mechanical equipment; and input the source noise signal to a noise reduction filter to determine the noise control signal at the sound emitting position.

[0150] In some embodiments, the first determining unit 91 is further configured to obtain an actual noise signal at the sound receiving position; determine a first original noise signal at the sound receiving position according to a difference between a noise control signal at the sound receiving position and the actual noise signal at the sound receiving position; and determine a second original noise signal at the target position according to the first original noise signal at the sound receiving position and the first signal transfer function.

[0151] In some embodiments, the first determining unit 91 is further configured to obtain a noise control signal at the sound emitting position; and determine a noise control signal at the sound receiving position according to the noise control signal at the sound emitting position and a third signal transfer function between the sound emitting position and the sound receiving position.

[0152] In some embodiments, the updating unit 93 is further configured to determine a coefficient of the noise reduction filter at a next time according to an error noise signal at a current time at the target position and a coefficient of the noise reduction filter at the current time; and update the coefficient of the noise reduction filter according to the coefficient of the noise reduction filter at the next time.

[0153] Figure 10 Schematic diagrams showing other embodiments of the noise control device of the present disclosure.

[0154] As shown in Figure 10 The noise control device 90 of this embodiment includes a memory 1001 and a processor 1002 coupled to the memory 1001, and the processor 1002 is configured to execute the noise control method in any one of the foregoing embodiments based on instructions stored in the memory 1001.

[0155] The memory 1001 may, for example, include a system memory, a fixed nonvolatile storage medium, etc. The system memory, for example, stores an operating system, an application program, a Boot Loader, and other programs, etc.

[0156] The noise control device 90 can also include an input / output interface 1003, a network interface 1004, a storage interface 1005, etc. These interfaces 1003, 1004, 1005, and the memory 1001 and the processor 1002 may, for example, be connected through a bus 1006. Among them, the input / output interface 1003 provides a connection interface for display, mouse, keyboard, touch screen, microphone, speaker, and other input / output devices. The network interface 1004 provides a connection interface for various networking devices. The storage interface 1005 provides a connection interface for external storage devices such as SD cards and U disks.

[0157] In the above embodiment, the relationship between the first original noise signal of the sound receiving position and the second original noise signal of the target position can be determined according to the first signal transfer function, which to some extent overcomes the limitations of the sound receiving position determination, reduces the influence of the sound receiving position on the noise reduction effect, can quickly select the sound receiving position, reduces the simulation cost, reduces the development cost, improves the efficiency of the noise control process, and can more accurately estimate and predict the second original noise signal of the target position (i.e., the noise signal at the target position). By the second original noise signal of the target position and the noise control signal of the target position, the error noise signal of the target position is determined, and the coefficients of the noise reduction filter are updated according to the error noise signal (or the characteristics of the noise in the feedback path), which realizes the adaptive adjustment of the noise control process of the mechanical equipment, can adjust the coefficients of the noise reduction filter in time according to the error noise signal to adapt to the changes of the environment and the target position, and ensures the stability and accuracy of the noise control process of the mechanical equipment. By realizing the adaptive adjustment of the noise control process of the mechanical equipment and ensuring the accuracy and stability of the noise control process, the noise level inside the cab of the mechanical equipment is reduced, and the experience and riding comfort of the operator or passenger of the mechanical equipment are significantly improved. In addition, the existing sound receiving device and sound externalizing device of the mechanical equipment are fully utilized, without the need for additional special hardware, which reduces the risk of increasing the manufacturing cost of the mechanical equipment and also reduces the risk of increasing the weight of the mechanical equipment, and can better meet the development demands of the mechanical equipment industry (i.e., lightweight and low energy consumption). In addition, the noise control method directly processes the source noise signal through the noise reduction filter, which can be applied to noise reduction of noise of various frequencies, and can make up for the limitations of passive noise control in low-frequency noise reduction.

[0158] Figure 11 A schematic diagram showing some embodiments of the noise control system of the present disclosure.

[0159] As Figure 11 shown, the noise control system 1100 includes the noise control device 90 in any of the above embodiments and a noise reduction filter 1101.

[0160] The noise reduction filter 1101 is configured to receive the source noise signal of the mechanical equipment sent by the noise control device, and generate a noise control signal corresponding to the source noise signal at the sound externalizing position.

[0161] In the above embodiment, the relationship between the first original noise signal of the sound receiving position and the second original noise signal of the target position can be determined according to the first signal transfer function, which to some extent overcomes the limitation of the sound receiving position determination, reduces the influence of the sound receiving position on the noise reduction effect, enables quick selection of the sound receiving position, reduces the simulation cost, reduces the development cost, improves the efficiency of the noise control process, and more accurately estimates and predicts the second original noise signal of the target position (i.e., the noise signal at the target position). By using the second original noise signal of the target position and the noise control signal of the target position, the error noise signal of the target position is determined, and the coefficients of the noise reduction filter are updated according to the error noise signal (or the characteristics of the noise in the feedback path), which realizes adaptive adjustment of the noise control process of the mechanical equipment, enables timely adjustment of the coefficients of the noise reduction filter according to the error noise signal to adapt to changes in the environment and the target position, and ensures the stability and accuracy of the noise control process of the mechanical equipment. By realizing adaptive adjustment of the noise control process of the mechanical equipment and ensuring the accuracy and stability of the noise control process, the noise level inside the cab of the mechanical equipment is reduced, and the experience and comfort of the operator or passenger of the mechanical equipment are significantly improved. In addition, the existing sound receiving device and sound external device of the mechanical equipment are fully utilized, without the need for additional special hardware, which reduces the risk of increasing the manufacturing cost of the mechanical equipment and the risk of increasing the weight of the mechanical equipment, and better meets the development demands of the mechanical equipment industry (i.e., lightweight and low energy consumption). In addition, the noise control method directly processes the source noise signal through the noise reduction filter, which can be applied to noise reduction of noise at various frequencies, and can make up for the limitations of passive noise control in low-frequency noise reduction.

[0162] In some embodiments, the noise control system 1100 further includes a sound external device configured to receive the noise control signal and externalize.

[0163] In some embodiments, the noise control system 1100 further includes a sound receiving device configured to detect the first original noise signal of the sound receiving position and send the first original noise signal of the sound receiving position to the noise control device 90.

[0164] In some embodiments, the sound receiving device is further configured to detect the first original noise training signal of the sound receiving position and the second original noise training signal of the target position, and send the first original noise training signal and the second original noise training signal to the noise control device 90, so that the noise control device 90 performs delay processing on the first original noise training signal, and determines the first signal transfer function according to the first original noise training signal after delay processing and the second original noise training signal.

[0165] In some embodiments, a computer program product is protected, comprising a computer program or instructions that, when executed by a processor, implement the noise control method described above. The computer program product includes a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowchart. In such embodiments, the computer program can be downloaded and installed from a network, installed from a storage device, or installed from ROM via a noise control device. When the computer program is executed by a CPU, it performs the functions defined in the methods of embodiments of this disclosure.

[0166] Those skilled in the art will understand that embodiments of this disclosure can be provided as methods, systems, or computer program products. Therefore, this disclosure can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this disclosure can take the form of a computer program product embodied on one or more computer-usable non-transitory storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0167] The noise control methods, apparatus, systems, and procedures of this disclosure have now been described in detail. To avoid obscuring the concept of this disclosure, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0168] The methods and systems of this disclosure may be implemented in many ways. For example, they may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above-described order of steps for the methods is for illustrative purposes only, and the steps of the methods of this disclosure are not limited to the order specifically described above, unless otherwise specifically stated. Furthermore, in some embodiments, this disclosure may also be implemented as a program recorded on a recording medium, the program including machine-readable instructions for implementing the methods according to this disclosure. Thus, this disclosure also covers recording media storing programs for performing the methods according to this disclosure.

[0169] While specific embodiments of this disclosure have been described in detail by way of example, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of this disclosure. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this disclosure. The scope of this disclosure is defined by the appended claims.

Claims

1. A noise control method, comprising: Based on the first original noise signal of the sound receiving position of the mechanical equipment and the first signal transfer function between the sound receiving position and the target position of the mechanical equipment, the second original noise signal of the target position is determined; Based on the second original noise signal of the target location and the noise control signal of the target location, the error noise signal of the target location is determined; The coefficients of the noise reduction filter are updated based on the error noise signal at the target position until the error noise signal at the target position is zero. The noise reduction filter is used to generate a noise control signal corresponding to the source noise signal of the mechanical equipment at the sound output position of the mechanical equipment.

2. The noise control method according to claim 1, further comprising, before determining the second original noise signal at the target location: Real-time monitoring of the first original noise training signal at the sound receiving position and the second original noise training signal at the target position; The first original noise training signal is delayed to obtain a delayed first original noise training signal. The first signal transfer function is determined based on the first original noise training signal and the second original noise training signal with the delay.

3. The noise control method according to claim 2, wherein, The first original noise training signal is delayed to obtain a delayed first original noise training signal, which includes: The first original noise training signal at the first moment is determined as the first original noise training signal at the second moment to obtain the delayed first original noise training signal, wherein the first moment is earlier than the second moment.

4. The noise control method according to claim 3, wherein, The process of delaying the first original noise training signal to obtain a delayed first original noise training signal further includes: After determining the first original noise training signal at the first time point as the first original noise training signal at the second time point, and if the first time point is the initial time point, the first original noise signal between the first time point and the second time point is determined as the zero signal.

5. The noise control method according to any one of claims 1 to 4, wherein, The error noise signal of the target location is determined based on the second original noise signal of the target location and the noise control signal of the target location, including: Based on the noise control signal of the sound output position of the mechanical equipment and the second signal transfer function between the sound output position and the target position, the noise control signal of the target position is determined; The error noise signal of the target location is determined by summing the second original noise signal of the target location and the noise control signal of the target location.

6. The noise control method according to claim 5, wherein, Determining the error noise signal of the target location based on the second original noise signal of the target location and the noise control signal of the target location further includes: Acquire the source noise signal of the mechanical equipment; The source noise signal is input to the noise reduction filter to determine the noise control signal at the sound amplification position.

7. The noise control method according to any one of claims 1 to 4, wherein, Determining the second original noise signal of the target position based on the first original noise signal of the receiving position of the mechanical equipment and the first signal transfer function between the receiving position and the target position of the mechanical equipment includes: Obtain the actual noise signal at the sound receiving location; The first original noise signal at the receiving position is determined based on the difference between the noise control signal at the receiving position and the actual noise signal at the receiving position. The second original noise signal at the target location is determined based on the first original noise signal at the receiving location and the first signal transfer function.

8. The noise control signal according to claim 7, wherein, The determination of the second original noise signal for the target position, based on the first original noise signal from the receiving position of the mechanical equipment and the first signal transfer function between the receiving position and the target position of the mechanical equipment, further includes: Obtain the noise control signal for the sound amplification position; The noise control signal for the sound receiving position is determined based on the noise control signal at the sound output position and the third signal transfer function between the sound output position and the sound receiving position.

9. The noise control method according to any one of claims 1 to 4, wherein, The coefficients of the noise reduction filter are updated based on the error noise signal at the target location, including: Based on the error noise signal at the current time of the target location and the coefficients of the noise reduction filter at the current time, determine the coefficients of the noise reduction filter at the next time. The coefficients of the noise reduction filter are updated based on the coefficients of the noise reduction filter at the next moment.

10. The noise control method according to any one of claims 2 to 4, wherein, Determining the first signal transfer function based on the delayed first original noise training signal and the second original noise training signal includes: Based on the delayed first original noise training signal and the second original noise training signal, determine the cross-spectral density matrix between the delayed first original noise training signal and the second original noise training signal; The first signal transfer function is determined based on the cross-spectral density matrix, the power spectral density matrix of the delayed first original noise training signal, and the stability factor.

11. The noise control method according to any one of claims 1 to 4, wherein, The sound receiving position can be one or more, the sound amplification position can be one or more, and the target position can be one or more.

12. The noise control method according to claim 4, wherein, The time difference between the second time point and the first time point is a preset threshold value.

13. A noise control device, comprising: The first determining unit is configured to determine the second original noise signal of the target position based on a first original noise signal of the sound receiving position of the mechanical device and a first signal transfer function between the sound receiving position and the target position of the mechanical device. The second determining unit is configured to determine an error noise signal of the target location based on a second original noise signal of the target location and a noise control signal of the target location; The updating unit is configured to update the coefficients of the noise reduction filter according to the error noise signal of the target position until the error noise signal of the target position is zero. The noise reduction filter is used to generate a noise control signal corresponding to the source noise signal of the mechanical equipment's sound output position based on the source noise signal of the mechanical equipment.

14. A noise control device, comprising: Memory; and A processor coupled to the memory, the processor being configured to execute the noise control method of any one of claims 1 to 12 based on instructions stored in the memory.

15. A noise control system, comprising: The noise control device as described in claim 13 or 14; A noise reduction filter is configured to receive the source noise signal of the mechanical equipment sent by the noise control device, and generate a noise control signal corresponding to the source noise signal at the sound amplification position.

16. The noise control system according to claim 15, further comprising: An external sound output device is configured to receive the noise control signal and output it externally.

17. A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the noise control method of any one of claims 1 to 12.

18. A computer program product comprising a computer program that, when executed by a processor, implements the noise control method of any one of claims 1 to 12.

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