Compensation noise reduction method and system for buffer block test bench

Abstract

The invention relates to a buffer block test bench compensation noise reduction method and system, and belongs to the field of noise control. The method comprises the following steps: synchronously capturing multi-physical field signals, and synchronously acquiring a buffer block dynamic load spectrum, a rack vibration acceleration signal and a sound pressure pulsation characteristic; establishing a mixed signal matrix based on the multi-physical field signal, obtaining a blind source separation matrix according to the mixed signal matrix, and deducing an independent noise source signal; constructing a self-adaptive compensation topology based on the independent noise source signals, and fusing transient errors to generate active noise reduction signals with time-varying step size constraints; a thermodynamic-signal coupling model is introduced, when the monitored temperature difference exceeds an allowable threshold value, an active noise reduction signal is regulated and controlled through a temperature difference time-lag 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. According to the method, the noise compensation process is regulated and controlled through the time-varying step size and the temperature difference time-lag parameters, the noise control efficiency is higher, and the effect is remarkable.

Description

Technical Field

[0001] The invention belongs to the technical field of noise control, and in particular 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 technology, the performance test requirements of automobile 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, and fatigue life) of the buffer block directly affects the NVH (noise, vibration, and harshness) performance of the vehicle. However, the traditional buffer block test bench faces the following key problems in noise reduction technology: Real-time defects of active noise reduction systems: Some high-end test benches have introduced active noise reduction technology based on the LMS (least mean square) algorithm, but there is an inherent contradiction in its fixed step size design. In order to maintain stability, the step size is usually small, resulting in a long convergence time for the algorithm, and the inability to track transient impact noise (such as noise with a pulse width of <5ms generated by the collision of the buffer block). In complex working conditions, the noise reduction effect is significantly attenuated as the test time increases. Blind spot identification of multi-physics field coupling noise: During the buffer block test, multi-physics 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 microphone) for noise analysis. Performance drift under environmental disturbance: When the test bench is running for a long time or the temperature difference changes, the thermal expansion / contraction of the mechanical structure will change the signal transmission path, causing the time delay parameter drift. The existing system lacks a dynamic compensation mechanism, which may cause the noise reduction performance to degrade. Summary of the invention

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

[0004] The purpose of the present invention can be achieved by the following technical solutions: A buffer block test bench compensation noise reduction method, the implementation of the buffer block test bench compensation noise reduction method comprises the following steps: Implement synchronous capture of multi-physics field signals to synchronously obtain 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 signal, obtaining a blind source separation matrix according to the mixed signal matrix, and deriving an independent noise source signal; Building an adaptive compensation topology based on the independent noise source signal, fusing the transient error to generate an active noise reduction signal with a time-varying step size constraint; A thermodynamic-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 hysteresis parameter to obtain a secondary active noise reduction signal. The buffer block test bench compensation noise reduction is performed based on the secondary active noise reduction signal.

[0005] Preferably, the derivation of the independent noise source signal includes: Construct blind source separation objective function; Iteratively optimize the blind source separation objective function to reach the minimum value, obtain the separation matrix, and obtain the blind source separation matrix Y=WX=[y1,y2,…,y n ], and n independent noise source signals are separated, where X is the mixed signal matrix and W is the separation matrix.

[0006] 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 ith noise source signal, y i is the signal of the ith noise source, and n is the number of noise sources.

[0007] Preferably, the generation of the active noise reduction signal includes: Capture the transient error signal e(n) and calculate the time-varying step size factor; According to the independent noise source signal, the modal vibration function is obtained by counting the noise-prone points, and the natural frequency is recorded. Based on the modal vibration function and the natural frequency, a structural compensation signal is generated. The mathematical description of the structural compensation signal is: , where M is the number of noisy bits, is the mth mode shape function at position x, is the mth mode shape function at position y, ω m is the mth order natural frequency, ω is the external excitation frequency, j is the imaginary unit, is the modal damping ratio; The active noise reduction signal is generated based on the structure compensation signal.

[0008] Preferably, the calculation formula of the time-varying step size factor is: ,in, is the minimum step length, is the maximum step size, α is the step size adjustment sensitivity coefficient, and the step size of the active noise reduction signal is constrained based on the time-varying step size factor.

[0009] Preferably, 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, The phase angle of the structure compensation signal.

[0010] Preferably, the acquisition of the secondary active noise reduction signal includes: Preset a reference temperature, obtain the real-time temperature, obtain the monitoring 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; Acquire the initial temperature difference hysteresis at the reference temperature, and calculate the temperature difference hysteresis parameter based on the initial temperature difference hysteresis and the linear temperature coefficient; The secondary active noise reduction signal is obtained by regulating the active noise reduction signal based on the temperature difference time lag parameter, which is mathematically described as ,in, is the secondary active noise reduction signal, is the temperature difference hysteresis parameter.

[0011] Preferably, the calculation formula of the linear temperature coefficient is: ,in, is the linear temperature coefficient, is the thermal expansion coefficient of the material, L0 is the length of the active noise reduction signal transmission path, and v is the signal propagation rate.

[0012] Preferably, the calculation formula of the temperature difference hysteresis parameter is: ,in, is the temperature difference hysteresis parameter, is the initial temperature difference lag, is the monitored temperature difference at time t.

[0013] A buffer block test bench compensation noise reduction system, used to execute the buffer block test bench compensation noise reduction method described above, comprising 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 synchronous capture of multi-physical field signals, and synchronously obtain the dynamic load spectrum of the buffer block, the vibration acceleration signal of the test bench, 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 signal, obtain a blind source separation matrix according to the mixed signal matrix, and derive an independent noise source signal; 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; The secondary compensation module is used to introduce a thermodynamic-signal coupling model. When the monitored temperature difference exceeds the allowable threshold, the active noise reduction signal is regulated by the temperature difference hysteresis parameter to obtain a secondary active noise reduction signal, and the buffer block test bench compensation noise reduction is performed based on the secondary active noise reduction signal.

[0014] The beneficial effects of the present invention are: (1) The step size of noise control is adjusted by a time-varying step size factor, achieving small step size anti-shake under impulse noise and large step size fast tracking under steady-state noise.

[0015] (2) Separate multiple mutually coupled multi-physical field noises such as mechanical vibration, hydraulic pulsation, and electromagnetic interference to improve noise reduction accuracy.

[0016] (3) The active noise reduction signal is regulated by the temperature difference hysteresis parameter to eliminate the influence of temperature difference in the noise reduction process, and the noise reduction effect is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0018] Figure 1 The present invention is a flowchart of the steps of a buffer block test bench compensation noise reduction method. DETAILED DESCRIPTION

[0019] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0020] The working principle and use process of the present invention: See also Figure 1 , a buffer block test bench compensation noise reduction method, comprising: S1: Implementing synchronous capture of multi-physical field signals through a heterogeneous sensor array, wherein the heterogeneous sensor array includes a piezoelectric force sensor, an accelerometer, and an acoustic array, and synchronously acquiring the dynamic load spectrum of the buffer block, the vibration acceleration signal of the bench, and the acoustic pressure pulsation characteristics; S2: Based on the multi-physical field signal, a mixed signal matrix X=[F, V, P] is established, 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 sound pressure pulsation characteristic. A blind source separation matrix is ​​obtained according to the mixed signal matrix to derive independent noise source signals; S3: constructing an adaptive compensation topology based on the independent noise source signal, fusing the transient error to generate an active noise reduction signal with a time-varying step size constraint; S4: In a mechanical system, temperature changes can cause thermal expansion / contraction of materials, thereby causing signal lag. Therefore, a thermodynamic-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 lag parameter to obtain a secondary active noise reduction signal. Based on the secondary active noise reduction signal, the buffer block test bench compensation noise reduction is performed to eliminate the influence of control delay.

[0021] In this embodiment, a blind source separation matrix is ​​obtained according to the mixed signal matrix to derive an independent noise source signal, which can be specifically implemented by the following steps: S201: Constructing blind source separation objective function , where W is the separation matrix, E is the expectation, P i is the probability density function of the ith noise source signal, y i is the signal of the ith noise source, and n is the number of noise sources; S202: Iteratively optimize the blind source separation objective function to reach a minimum value, obtain the separation matrix, and obtain the blind source separation matrix Y=WX=[y1,y2,…,y n ], and separate n independent noise source signals, such as mechanical gear meshing noise, background electromagnetic interference noise, hydraulic system cavitation noise, etc.

[0022] In this embodiment, an adaptive compensation topology is constructed based on the independent noise source signal, and a transient error is integrated to generate an active noise reduction signal with a time-varying step size constraint, which can be specifically implemented by the following steps: S301: Capture the transient error signal e(n) and calculate the time-varying step factor. The calculation formula is: ,in, is the minimum step size, the default value is 0.001, is the maximum step size, the default value is 0.1, which is used to accelerate convergence; α is the step size adjustment sensitivity coefficient, the default value is 0.5, based on the time-varying step size factor to constrain the step size of the active noise reduction signal, that is, when the noise is stable (e(n) is small), μ(n) takes a larger value, which can accelerate convergence; when the noise changes suddenly (e(n) is large), μ(n) takes a smaller value, which can prevent divergence; S302: Count the noise-prone points according to the independent noise source signal to obtain a modal vibration function (such as a displacement mode when the point vibration generates noise), and record the natural frequency. The noise-prone points are points in the buffer block test bench that are prone to generate noise. A structural compensation signal is generated based on the modal vibration function and the natural frequency. The mathematical description of the structural compensation signal is: , where M is the number of noisy bits, is the mth mode shape function at position x, is the mth mode shape function at position y, ω m is the mth order natural frequency, ω is the external excitation frequency, j is the imaginary unit, is the modal damping ratio; 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 Fcomp (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, The phase angle of the structure compensation signal.

[0023] In this embodiment, the buffer block test bench compensation noise reduction is performed based on the secondary active noise reduction signal, which can be specifically implemented by the following steps: S401: preset a reference temperature, obtain the real-time temperature, obtain the monitoring 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: ,in, is the linear temperature coefficient, is the thermal expansion coefficient of the material, L0 is the length of the active noise reduction signal transmission path, and v is the signal propagation rate; S402: Obtain the initial temperature difference hysteresis at the reference temperature, and calculate the temperature difference hysteresis parameter based on the initial temperature difference hysteresis and the linear temperature coefficient. The calculation formula is: ,in, is the temperature difference hysteresis parameter, is the initial temperature difference lag, is the monitored temperature difference at time t; S403: Based on the temperature difference hysteresis parameter, the active noise reduction signal is regulated to obtain the secondary active noise reduction signal, which is mathematically described as ,in, For example: if the reference temperature is set to 25°C and the real-time temperature is set to 60°C, the monitored temperature difference is 35°C, the active noise reduction signal transmission path length is 0.5m, the thermal expansion coefficient of steel is 12ppm / °C, and the mechanical signal propagation rate is 5000m / s, then the linear temperature coefficient is (12×10 -6 ×0.5) / 5000=0.0012ms / ℃. When the initial temperature difference lag is 0.2ms, the temperature difference lag parameter is 0.2+0.0012×35=0.242ms. That is, releasing the active noise reduction signal 0.242ms in advance can achieve a better noise reduction effect.

[0024] A buffer block test bench compensation noise reduction system, comprising 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 synchronous capture of multi-physical field signals through a heterogeneous sensor array, wherein the heterogeneous sensor array includes a piezoelectric force sensor, an accelerometer, and an acoustic array, and synchronously acquires a dynamic load spectrum of a buffer block, a vibration acceleration signal of a test bench, and acoustic pressure pulsation characteristics; The noise source separation module is used to establish a mixed signal matrix X=[F, V, P] based on the multi-physical field signal, 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 sound pressure pulsation characteristic. A blind source separation matrix is ​​obtained according to the mixed signal matrix to derive an independent noise source signal; 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; The secondary compensation module is used in mechanical systems. Temperature changes can cause thermal expansion / contraction of materials, thereby causing signal lag. Therefore, a thermodynamic-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 lag parameter to obtain a secondary active noise reduction signal. Based on the secondary active noise reduction signal, the buffer block test bench compensation noise reduction is performed to eliminate the influence of control delay.

[0025] The computer storage medium of the embodiment of the present invention may adopt any combination of one or more computer-readable media. The computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples (non-exhaustive list) of computer-readable storage media include: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In this document, a computer-readable storage medium may be any tangible medium containing or storing a program that may be used by or in combination with an instruction execution system, device or device.

[0026] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, which carry computer-readable program code. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. Computer-readable signal media may also be any computer-readable medium other than a computer-readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0027] The program code included on the computer readable medium can be transmitted with any appropriate medium, including but not limited to wireless, electric wire, optical cable, RF, etc., or any suitable combination of the above. The computer program code for performing the operation of the present invention can be written in one or more programming languages ​​or their combinations, and the programming language includes object-oriented programming languages-such as Java, Smalltalk, C++, and also includes conventional procedural programming languages-such as "C" language or similar programming languages. The program code can be executed completely on the user's computer, partially on the user's computer, as an independent software package, partially on the user's computer and partially on the remote computer, or completely on the 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 it can be connected to an external computer (for example, using an Internet service provider to connect through the Internet).

[0028] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A buffer block test bench compensation noise reduction method, characterized in that: The implementation of the buffer block test bench compensation noise reduction method includes the following steps: Implement synchronous capture of multi-physics field signals to synchronously obtain 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 signal, obtaining a blind source separation matrix according to the mixed signal matrix, and deriving an independent noise source signal; Building an adaptive compensation topology based on the independent noise source signal, fusing the transient error to generate an active noise reduction signal with a time-varying step size constraint; A thermodynamic-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 hysteresis parameter to obtain a secondary active noise reduction signal. The buffer block test bench compensation noise reduction is performed based on the secondary active noise reduction signal.

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

3. The buffer block test bench compensation noise reduction method according to claim 2, characterized in that: 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 ith noise source signal, y i is the ith noise source signal, and n is the number of noise sources.

4. The buffer block test bench compensation 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; According to the independent noise source signal, the modal vibration function is obtained by counting the noise-prone points, and the natural frequency is recorded. Based on the modal vibration function and the natural frequency, a structural compensation signal is generated. The mathematical description of the structural compensation signal is: , where M is the number of noisy bits, is the mth mode shape function at position x, is the mth mode shape function at position y, ω m is the mth order natural frequency, ω is the external excitation frequency, j is the imaginary unit, is the modal damping ratio; The active noise reduction signal is generated 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: ,in, is the minimum step length, is the maximum step size, α is the step size adjustment sensitivity coefficient, and the step size of the active noise reduction signal is constrained based on the time-varying step size factor.

6. The buffer block test bench compensation noise reduction method according to claim 5, characterized in that: 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, The phase angle of the structure compensation signal.

7. The buffer block test bench compensation noise reduction method according to claim 1, characterized in that: The acquisition of the secondary active noise reduction signal includes: Preset a reference temperature, obtain the real-time temperature, obtain the monitoring 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; Acquire the initial temperature difference hysteresis at the reference temperature, and calculate the temperature difference hysteresis parameter based on the initial temperature difference hysteresis and the linear temperature coefficient; The secondary active noise reduction signal is obtained by regulating the active noise reduction signal based on the temperature difference hysteresis parameter, which is mathematically described as ,in, is the secondary active noise reduction signal, is the temperature difference hysteresis parameter.

8. The buffer block test bench compensation noise reduction method according to claim 7, characterized in that: The calculation formula of the linear temperature coefficient is: ,in, is the linear temperature coefficient, is the thermal expansion coefficient of the material, L0 is the length of the active noise reduction 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 of the temperature difference hysteresis parameter is: ,in, is the temperature difference hysteresis parameter, is the initial temperature difference lag, is the monitored temperature difference at time t.

10. A buffer block test bench compensation noise reduction system, characterized in that: The system is applied to the buffer block test bench compensation noise reduction method as described in any one of claims 1 to 9, including 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 synchronous capture of multi-physical field signals, and synchronously obtain the dynamic load spectrum of the buffer block, the vibration acceleration signal of the test bench, 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 signal, obtain a blind source separation matrix according to the mixed signal matrix, and derive an independent noise source signal; 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; The secondary compensation module is used to introduce a thermodynamic-signal coupling model. When the monitored temperature difference exceeds the allowable threshold, the active noise reduction signal is regulated by the temperature difference hysteresis parameter to obtain a secondary active noise reduction signal, and the buffer block test bench compensation noise reduction is performed based on the secondary active noise reduction signal.

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