A buffering block test bench compensation and noise reduction method and system

Abstract

The present invention relates to a method and system for compensating and reducing noise of a buffer block test bench, belonging to the field of noise control. Among them, the method includes implementing synchronous capture of multi-physical field signals, synchronously obtaining the dynamic load spectrum of the buffer block, the vibration acceleration signal of the test bench, and the sound pressure pulsation characteristics; establishing a mixed signal matrix based on the multi-physical field signals, obtaining a blind source separation matrix according to the mixed signal matrix, and deriving the independent noise source signals; constructing an adaptive compensation topology based on the independent noise source signals, fusing the transient error to generate an active noise reduction signal with a time-varying step size constraint; introducing a thermodynamics-signal coupling model, when the monitored temperature difference exceeds the allowable threshold, regulating the active noise reduction signal through the temperature difference time-delay parameter to obtain a secondary active noise reduction signal, and performing compensation and noise reduction on the buffer block test bench based on the secondary active noise reduction signal. The present invention realizes the regulation of the noise compensation process through the time-varying step size and the temperature difference time-delay parameter, with higher noise control efficiency and remarkable effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of noise control, and particularly relates to a compensation noise reduction method and system for a buffer block test bench. Background Art

[0002] With the rapid development of new energy vehicles and intelligent driving technologies, the performance test requirements for automotive suspension systems are becoming increasingly stringent. As a key component in the suspension system, the test accuracy of the dynamic characteristics (such as stiffness, damping, fatigue life) of the buffer block directly affects the NVH (Noise, Vibration, and Harshness) performance of the whole vehicle. However, traditional buffer block test benches face the following key problems in noise reduction technology: Real-time defect of the active noise reduction system: Some high-end test benches introduce active noise reduction technology based on the LMS (Least Mean Square) algorithm, but its fixed step size design has an inherent contradiction. To maintain stability, the step size is usually small, resulting in a long algorithm convergence time, unable to track transient impact noise (such as noise with a pulse width <5ms generated by the collision of the buffer block), and in complex working conditions, the noise reduction effect significantly decays with the extension of the test time. Identification blind area of multi-physical field coupled noise: During the buffer block test process, multi-physical field noises such as mechanical vibration, hydraulic pulsation, and electromagnetic interference are coupled with each other, and existing systems often use a single sensor (such as only an accelerometer or a microphone) for noise analysis. Performance drift under environmental disturbances: When the test bench runs for a long time or the temperature difference changes, the thermal expansion / contraction of the mechanical structure will change the signal transmission path, resulting in the drift of time-delay parameters. Existing systems lack a dynamic compensation mechanism, which may lead to the attenuation of noise reduction performance. Summary of the Invention

[0003] To solve the above problems existing in the prior art, the present invention provides a compensation noise reduction method and system for a buffer block test bench.

[0004] The object of the present invention can be achieved by the following technical solutions:

[0005] A compensation noise reduction method for a buffer block test bench, the implementation of the compensation noise reduction method for the buffer block test bench includes the following steps:

[0006] Implement multi-physical field signal synchronous capture, and synchronously obtain the buffer block dynamic load spectrum, the bench vibration acceleration signal, and the sound pressure pulsation characteristics;

[0007] Based on the multi-physical field signals, establish a mixed signal matrix, obtain a blind source separation matrix according to the mixed signal matrix, and deduce the independent noise source signals;

[0008] Based on the independent noise source signals, construct an adaptive compensation topology, and fuse transient errors to generate an active noise reduction signal with a time-varying step size constraint;

[0009] Introduce a thermodynamics-signal coupling model. When the monitored temperature difference exceeds the allowable threshold, the active noise reduction signal is regulated through the temperature difference time-delay parameter to obtain a secondary active noise reduction signal, and buffer block test bench compensation noise reduction is performed based on the secondary active noise reduction signal.

[0010] Preferably, the derivation of the independent noise source signal includes:

[0011] Construct a blind source separation objective function;

[0012] Iteratively optimize the blind source separation objective function to reach the minimum value, obtain the separation matrix, and based on the separation matrix and the mixed signal matrix, obtain the blind source separation matrix Y = WX = [y1, y2, …, y n , and separate n independent noise source signals, where X is the mixed signal matrix and W is the separation matrix.

[0013] Preferably, the expression of the blind source separation objective function is , where W is the separation matrix, E is the expectation, P i is the probability density function of the i-th noise source signal, y i is the i-th noise source signal, and n is the number of noise sources.

[0014] Preferably, the generation of the active noise reduction signal includes:

[0015] Capture the transient error signal e(n) and calculate the time-varying step size factor;

[0016] According to the independent noise source signals, statistically obtain the modal shape function of the noise-prone points and record the natural frequency. Generate a structure compensation signal based on the modal shape function and the natural frequency. The mathematical description of the structure compensation signal is , where M is the number of noise-prone points, is the m-th order modal shape function at position x, is the m-th order modal shape function at position y, ω m is the m-th order natural frequency, ω is the external excitation frequency, j is the imaginary unit, is the modal damping ratio;

[0017] Generate the active noise reduction signal based on the structure compensation signal.

[0018] Preferably, the calculation formula of the time-varying step size factor is , where, is the minimum step size, is the maximum step size, and α is the step size adjustment sensitivity coefficient. Constrain the step size of the active noise reduction signal based on the time-varying step size factor.

[0019] Preferably, the expression of the active noise reduction signal is , where F comp (t) is the active noise cancellation signal at time t, φ is the angular frequency of the noise signal, is the amplitude of the structural compensation signal, is the phase angle of the structural compensation signal.

[0020] Preferably, the acquisition of the secondary active noise cancellation signal includes:

[0021] Preset a reference temperature, obtain the real-time temperature, obtain the monitored temperature difference based on the difference between the real-time temperature and the reference temperature, obtain the length of the active noise cancellation signal transmission path, the coefficient of thermal expansion of the material, and the signal propagation rate, and calculate the linear temperature coefficient;

[0022] Obtain the initial temperature difference time lag at the reference temperature, and calculate the temperature difference time lag parameter based on the initial temperature difference time lag and the linear temperature coefficient;

[0023] Regulate the active noise cancellation signal based on the temperature difference time lag parameter to obtain the secondary active noise cancellation signal, and the mathematical description is , where is the secondary active noise cancellation signal, is the temperature difference time lag parameter.

[0024] Preferably, the calculation formula of the linear temperature coefficient is , where is the linear temperature coefficient, is the coefficient of thermal expansion of the material, L0 is the length of the active noise cancellation signal transmission path, and v is the signal propagation rate.

[0025] Preferably, the calculation formula of the temperature difference time lag parameter is , where is the temperature difference time lag parameter, is the initial temperature difference time lag, is the monitored temperature difference at time t.

[0026] A buffer block test bench compensation noise reduction system for implementing the buffer block test bench compensation noise reduction method described above, including a signal capture module, a noise source separation module, an active noise cancellation module, and a secondary compensation module;

[0027] The signal capture module is used to synchronously capture multi-physical field signals, and synchronously obtain the buffer block dynamic load spectrum, the bench vibration acceleration signal, and the sound pressure pulsation characteristics;

[0028] The noise source separation module is used to establish a mixed signal matrix based on the multi-physical field signals, obtain a blind source separation matrix according to the mixed signal matrix, and deduce the independent noise source signal;

[0029] The active noise reduction module is used to construct an adaptive compensation topology based on the independent noise source signal, and fuse the transient error to generate an active noise reduction signal with a time-varying step size constraint.

[0030] The secondary compensation module is used to introduce a thermodynamics-signal coupling model. When the monitored temperature difference exceeds the allowable threshold, the active noise reduction signal is regulated by the temperature difference time-delay parameter to obtain a secondary active noise reduction signal, and buffer block test bench compensation noise reduction is performed based on the secondary active noise reduction signal.

[0031] The beneficial effects of the present invention are as follows:

[0032] (1) The step size of noise control is adjusted by a time-varying step size factor, realizing small-step anti-shake under impact noise and large-step fast tracking under steady-state noise.

[0033] (2) Multiple mutually coupled multi-physical field noises such as mechanical vibration, hydraulic pulsation, and electromagnetic interference are separated to improve the noise reduction accuracy.

[0034] (3) The active noise reduction signal is regulated by the temperature difference time-delay parameter to eliminate the influence of temperature difference during the noise reduction process, and the noise reduction effect is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] For the convenience of those skilled in the art to understand, the present invention will be further described below with reference to the accompanying drawings.

[0036] Figure 1 It is a flowchart of the steps of a buffer block test bench compensation noise reduction method of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0037] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following will, with reference to the accompanying drawings and preferred embodiments, describe in detail the specific embodiments, structures, features and their effects according to the present invention.

[0038] The working principle and usage process of the present invention:

[0039] Please refer to Figure 1 , a buffer block test bench compensation noise reduction method, including:

[0040] S1: Synchronously capture multi-physical field signals through a heterogeneous sensor array, and the heterogeneous sensor array includes a piezoelectric force sensor, an accelerometer, and an acoustic array, and synchronously obtain the buffer block dynamic load spectrum, the test bench vibration acceleration signal, and the sound pressure pulsation characteristics.

[0041] S2: Based on the multi-physical field signals, establish a mixed signal matrix X = [F, V, P], where F is the dynamic load spectrum of the buffer block, V is the vibration acceleration signal of the test bench, and P is the characteristic of the acoustic pressure pulsation. Obtain the blind source separation matrix according to the mixed signal matrix, and deduce the independent noise source signals;

[0042] S3: Based on the independent noise source signals, construct an adaptive compensation topology, and fuse the transient error to generate an active noise reduction signal with a time-varying step size constraint;

[0043] S4: In a mechanical system, temperature changes can cause thermal expansion / contraction of materials, resulting in signal time delay. Therefore, a thermodynamics-signal coupling model is introduced. When the monitored temperature difference exceeds the allowable threshold, the active noise reduction signal is regulated by the temperature difference time delay parameter to obtain a secondary active noise reduction signal. Based on the secondary active noise reduction signal, buffer block test bench compensation noise reduction is carried out to eliminate the influence of control delay.

[0044] In this embodiment, obtaining the blind source separation matrix according to the mixed signal matrix and deducing the independent noise source signals can be specifically implemented through the following steps:

[0045] S201: Construct a blind source separation objective function , where W is the separation matrix, E is the expectation, P i is the probability density function of the i-th noise source signal, y i is the i-th noise source signal, and n is the number of noise sources;

[0046] S202: Iteratively optimize the blind source separation objective function to reach the minimum value, obtain the separation matrix, and based on the separation matrix and the mixed signal matrix, obtain the blind source separation matrix Y = WX = [y1, y2,..., y n , and separate out n independent noise source signals, such as mechanical gear meshing noise, background electromagnetic interference noise, hydraulic system cavitation noise, etc.

[0047] In this embodiment, constructing an adaptive compensation topology based on the independent noise source signals and fusing the transient error to generate an active noise reduction signal with a time-varying step size constraint can be specifically implemented through the following steps:

[0048] S301: Capture the transient error signal e(n) and calculate the time-varying step size factor. The calculation formula is , where is the minimum step size, and the default value is 0.001, is the maximum step size, with a default value of 0.1, which is used to accelerate convergence. α is the step size adjustment sensitivity coefficient, with a default value of 0.5. The step size of the active noise reduction signal is constrained based on the time-varying step size factor. That is, when the noise is stationary (e(n) is small), μ(n) takes a larger value, which can accelerate convergence. When the noise changes abruptly (e(n) is large), μ(n) takes a smaller value, which can prevent divergence;

[0049] S302: Obtain the modal shape function (such as the displacement mode when the point vibration generates noise) according to the independent noise source signal statistics of the noise-prone points, and record the natural frequency. The noise-prone points are the points in the buffer block test bench that are prone to generating noise. Generate a structural compensation signal based on the modal shape function and the natural frequency. The mathematical description of the structural compensation signal is , where M is the number of noise-prone points, is the m-th order modal shape function at position x, is the m-th order modal shape function at position y, ω m is the m-th order natural frequency, ω is the external excitation frequency, and j is the imaginary unit, is the modal damping ratio;

[0050] S303: Generate the active noise reduction signal based on the structural compensation signal to achieve compensation noise reduction of the buffer block test bench. The expression of the active noise reduction signal is , where, F comp (t) is the active noise reduction signal at time t, φ is the angular frequency of the noise signal, is the amplitude of the structural compensation signal, is the phase angle of the structural compensation signal.

[0051] In this embodiment, based on the secondary active noise reduction signal, compensation noise reduction of the buffer block test bench is carried out. Specifically, it can be implemented through the following steps:

[0052] S401: Preset a reference temperature, obtain the real-time temperature, obtain the monitored temperature difference based on the difference between the real-time temperature and the reference temperature, obtain the active noise reduction signal transmission path length, material thermal expansion coefficient, and signal propagation rate, and calculate the linear temperature coefficient. The calculation formula is , where, is the linear temperature coefficient, is the material thermal expansion coefficient, L0 is the active noise reduction signal transmission path length, and v is the signal propagation rate;

[0053] S402: Obtain the initial temperature difference time lag at the reference temperature, and calculate the temperature difference time lag parameter based on the initial temperature difference time lag and the linear temperature coefficient. The calculation formula is , where, is the temperature difference time lag parameter, is the initial temperature difference time delay, is the monitored temperature difference at time t;

[0054] S403: Based on the temperature difference time delay parameter, adjust the active noise cancellation signal to obtain the secondary active noise cancellation signal, and the mathematical description is , where is the secondary active noise cancellation signal. Example: Set the reference temperature to 25°C and the real-time temperature to 60°C, then the monitored temperature difference is 35°C, the transmission path length of the active noise cancellation signal is 0.5m, the thermal expansion coefficient of steel is 12ppm / °C, and the mechanical signal propagation speed is 5000m / s. Then the linear temperature coefficient is (12×10 -6 ×0.5) / 5000 = 0.0012ms / °C. When the initial temperature difference time delay is 0.2ms, the temperature difference time delay parameter can be obtained as 0.2 + 0.0012×35 = 0.242ms, that is, releasing the active noise cancellation signal 0.242ms in advance can obtain better noise cancellation effect.

[0055] A buffer block test bench compensation noise cancellation system includes a signal capture module, a noise source separation module, an active noise cancellation module, and a secondary compensation module;

[0056] The signal capture module is used to synchronously capture multi-physical field signals through a heterogeneous sensor array. The heterogeneous sensor array includes a piezoelectric force sensor, an accelerometer, and an acoustic array, and synchronously obtains the buffer block dynamic load spectrum, the test bench vibration acceleration signal, and the sound pressure pulsation characteristics;

[0057] The noise source separation module is used to establish a mixed signal matrix X = [F, V, P] based on the multi-physical field signals, where F is the buffer block dynamic load spectrum, V is the test bench vibration acceleration signal, and P is the sound pressure pulsation characteristic. According to the mixed signal matrix, obtain the blind source separation matrix and deduce the independent noise source signal;

[0058] The active noise cancellation module is used to construct an adaptive compensation topology based on the independent noise source signal, and fuse the transient error to generate an active noise cancellation signal with a time-varying step size constraint;

[0059] The secondary compensation module is used in a mechanical system. Temperature changes will cause the material to thermally expand / contract, resulting in signal time delay. Therefore, a thermodynamics-signal coupling model is introduced. When the monitored temperature difference exceeds the allowable threshold, the active noise cancellation signal is adjusted by the temperature difference time delay parameter to obtain the secondary active noise cancellation signal, and buffer block test bench compensation noise cancellation is performed based on the secondary active noise cancellation signal to eliminate the influence of control delay.

[0060] The computer storage medium of the embodiments of the present invention may adopt any combination of one or more computer-readable media. The computer-readable media may be computer-readable signal media or computer-readable storage media. The computer-readable storage media may, for example, but are not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or components, or any combination of the above. More specific examples (non-exhaustive list) of the computer-readable storage media include: electrical connections with one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the above. In this document, the computer-readable storage media may be any tangible medium that contains or stores a program, and this program can be used by or in combination with an instruction execution system, device, or component.

[0061] The computer-readable signal media may include data signals propagated in a baseband or as part of a carrier wave, which carry computer-readable program codes. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The computer-readable signal media may also be any computer-readable medium other than the computer-readable storage media, and this computer-readable medium can send, propagate, or transmit a program for use by or in combination with an instruction execution system, device, or component.

[0062] The program codes contained on the computer-readable media can be transmitted by any appropriate medium, including but not limited to wireless, wire, optical cable, RF, etc., or any suitable combination of the above. The computer program codes for performing the operations of the present invention can be written in one or more programming languages or combinations thereof. The programming languages include object-oriented programming languages such as Java, Smalltalk, C++, and also include conventional procedural programming languages such as the "C" language or similar programming languages. The program codes can be executed entirely on the user's computer, partially on the user's computer, executed as an independent software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer can be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computer (for example, by using an Internet service provider to connect through the Internet).

[0063] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments by using the above-disclosed technical content within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A compensation and noise reduction method for a buffer block test bench, characterized in that The implementation of the buffer block test bench compensation and noise reduction method includes the following steps: Implement multi-physical field signal synchronous capture to synchronously obtain the buffer block dynamic load spectrum, the test bench vibration acceleration signal, and the sound pressure pulsation characteristics; Based on the multi-physical field signals, establish a mixed signal matrix, obtain a blind source separation matrix according to the mixed signal matrix, and deduce the independent noise source signals; Based on the independent noise source signals, construct an adaptive compensation topology, and fuse the transient error to generate an active noise reduction signal with a time-varying step size constraint; Introduce a thermodynamics-signal coupling model. When the monitored temperature difference exceeds the allowable threshold, regulate the active noise reduction signal through the temperature difference time delay parameter to obtain a secondary active noise reduction signal, and perform buffer block test bench compensation and noise reduction based on the secondary active noise reduction signal.

2. The buffer block test bench compensation and noise reduction method according to claim 1, wherein The deduction of the independent noise source signals includes: Construct a blind source separation objective function; Iteratively optimize the blind source separation objective function to reach the minimum value, obtain the separation matrix, and based on the separation matrix and the mixed signal matrix, obtain the blind source separation matrix Y = WX = [y1, y2, …, y n , and separate n independent noise source signals, where X is the mixed signal matrix and W is the separation matrix.

3. The buffer block test bench compensation and noise reduction method according to claim 2, wherein, The expression of the blind source separation objective function is , where W is the separation matrix, E is the expectation, and P i is the probability density function of the i-th noise source signal, y i is the i-th noise source signal, and n is the number of noise sources.

4. The buffer block test bench compensation and noise reduction method according to claim 1, characterized in that The generation of the active noise reduction signal includes: Capture the transient error signal e(n) and calculate the time-varying step size factor; The modal shape function is obtained according to the noise-prone point positions of the independent noise source signals, and the natural frequencies are recorded. A structural compensation signal is generated based on the modal shape function and the natural frequencies. The mathematical description of the structural compensation signal is , where M is the number of noise-prone point positions, is the m-th order modal shape function at position x, is the m-th order modal shape function at position y, ω m is the m-th order natural frequency, ω is the external excitation frequency, j is the imaginary unit, is the modal damping ratio; Generate the active noise reduction signal based on the structure compensation signal.

5. The buffer block test bench compensation noise reduction method according to claim 4, characterized in that, The calculation formula of the time-varying step size factor is , where is the minimum step size, is the maximum step size, and α is the step size adjustment sensitivity coefficient. The step size of the active noise cancellation signal is constrained based on the time-varying step size factor.

6. The buffer block test bench compensation and noise reduction method according to claim 5, characterized in that, The expression of the active noise cancellation signal is , where F comp (t) is the active noise cancellation signal at time t, φ is the angular frequency of the noise signal, is the amplitude of the structural compensation signal, is the phase angle of the structural compensation signal.

7. The buffer block test bench compensation and noise reduction method according to claim 6, characterized in that The acquisition of the secondary active noise reduction signal includes: Preset a reference temperature, obtain the real-time temperature, obtain the monitored temperature difference based on the difference between the real-time temperature and the reference temperature, obtain the active noise reduction signal transmission path length, the material thermal expansion coefficient, and the signal propagation rate, and calculate the linear temperature coefficient; Obtain the initial temperature difference time delay at the reference temperature, and calculate the temperature difference time delay parameter based on the initial temperature difference time delay and the linear temperature coefficient; Adjust the active noise cancellation signal based on the temperature difference time delay parameter to obtain the secondary active noise cancellation signal, and the mathematical description is , where is the secondary active noise cancellation signal, is the temperature difference time delay parameter.

8. The buffer block test bench compensation noise reduction method according to claim 7, characterized in that The calculation formula for the linear temperature coefficient is , where is the linear temperature coefficient, is the coefficient of thermal expansion of the material, L0 is the length of the active noise cancellation signal transmission path, and v is the signal propagation rate.

9. The buffer block test bench compensation noise reduction method according to claim 8, characterized in that, The calculation formula for the temperature difference time lag parameter is , where is the temperature difference time lag parameter,[ is the initial temperature difference time lag,[ is the monitored temperature difference at time t.[ 10. A compensation and noise reduction system for a buffer block test bench, characterized in that, The system is applied to the buffer block test bench compensation and noise reduction method as described in any one of claims 1-9, and includes a signal capture module, a noise source separation module, an active noise reduction module, and a secondary compensation module; The signal capture module is used to implement multi-physical field signal synchronous capture to synchronously obtain the buffer block dynamic load spectrum, the test bench vibration acceleration signal, and the sound pressure pulsation characteristics; The noise source separation module is used to establish a mixed signal matrix based on the multi-physical field signals, obtain a blind source separation matrix according to the mixed signal matrix, and deduce the independent noise source signals; The active noise reduction module is used to construct an adaptive compensation topology based on the independent noise source signals, and fuse the transient error to generate an active noise reduction signal with a time-varying step size constraint; The secondary compensation module is used to introduce a thermodynamics-signal coupling model. When the monitored temperature difference exceeds the allowable threshold, regulate the active noise reduction signal through the temperature difference time delay parameter to obtain a secondary active noise reduction signal, and perform buffer block test bench compensation and noise reduction based on the secondary active noise reduction signal.

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