Commercial vehicle steering wheel NVH transfer function test method and device and storage medium

Abstract

The invention relates to a commercial vehicle steering wheel NVH transfer function test method and device and a storage medium. The method comprises the following steps: determining a target structure having a nonlinear influence on a transfer function in a commercial vehicle steering system, and preprocessing the target structure to eliminate the nonlinear influence of the target structure on the transfer function when a steering wheel transfer function test is carried out; the method comprises the following steps of: testing a transfer function of a steering wheel of a steering system: arranging an acceleration sensor on the steering wheel of a vehicle which is preset according to conditions; vibration excitation source parameters are set, vibration excitation is carried out, acceleration sensor signals are used as output, and vibration excitation signals are used as input; in the transfer function fitting process, Fourier transform is carried out on input and output signals, time domain signals are converted into frequency domain signals, cross spectrum of the input and output signals is calculated, self spectrum of the input signals is calculated, frequency response function is calculated by using the cross spectrum and the self spectrum, and the transfer function is fitted through a least square method; and acquiring the NVH property of the steering wheel of the commercial vehicle based on the transfer function.

Description

Technical Field

[0001] The present invention relates to the field of vehicle steering wheel NVH technology, and in particular to a commercial vehicle steering wheel NVH transfer function testing method, device and storage medium. Background Art

[0002] As an important system of the automobile chassis, the performance of the steering system directly affects the smoothness, handling stability and comfort of the entire vehicle, and its impact on the NVH (Noise, Vibration, Harshness) performance of the vehicle is particularly obvious. The vibration of the steering system is mostly reflected in the steering wheel, and the research on the vibration of the steering system is mainly the analysis of the steering wheel vibration. The jitter of the steering wheel not only directly reflects the vibration of the steering system components, but also directly affects the driver to cause fatigue driving, improper operation, traffic accidents and other problems, threatening the driving safety of the car. The vibration test of the steering wheel is an effective means to evaluate the NVH performance of the steering system and determine the natural frequency of the steering system. However, for some models, due to the structural contact uncertainty and damping uncertainty in the steering system, the transfer function amplitude and frequency of the steering wheel in the NVH transfer function test fluctuate irregularly. It is impossible to judge the pros and cons of the steering wheel structure and to support the effect of the optimization plan. For example Figure 2 Even if the same vehicle is tested under the same conditions, the transfer function will have large differences in the location and magnitude of the amplitude. Summary of the invention

[0003] In order to solve the above technical problem or at least partially solve the above technical problem, the present invention provides a commercial vehicle steering wheel NVH transfer function testing method, device and storage medium.

[0004] In a first aspect, the present invention provides a method for testing the NVH transfer function of a commercial vehicle steering wheel, comprising:

[0005] Determine the target structure in the commercial vehicle steering system that has a nonlinear effect on the transfer function, and pre-process the target structure when testing the steering wheel transfer function to eliminate the nonlinear effect of the target structure on the transfer function;

[0006] After eliminating the nonlinear influence of the target structure through preprocessing, the transfer function test of the steering wheel of the steering system is carried out, including: setting an acceleration sensor on the steering wheel of the vehicle pre-set according to conditions; setting the excitation source parameters, performing excitation, with the acceleration sensor signal as the output and the excitation signal as the input; in the transfer function fitting process, Fourier transform is performed on the input and output signals, the time domain signal is converted into a frequency domain signal, the cross-spectrum Y(ω) of the input and output signals is calculated, the auto-spectrum X(ω) of the input signal is calculated, and the frequency response function is calculated using the cross-spectrum and auto-spectrum: H(ω)=Y(ω) / X(ω), and finally the transfer function is fitted by the least squares method; the NVH properties of the commercial vehicle steering wheel are obtained based on the transfer function.

[0007] Furthermore, during the test, the vehicle is parked in advance in a horizontal field where noise and vibration are controlled, the engine is turned off, the steering wheel is returned to the center position, and the vehicle is parked in P gear; the acceleration sensor is pasted to the 9 o'clock and 12 o'clock positions of the steering wheel; a force hammer is used as an excitation source, the force hammer adopts a rubber hammer head, the excitation frequency band range is 1-200Hz, a counterweight block is applied to the end of the force hammer, and the force hammer sensitivity is 2.224N / mv; the force hammer strikes the 3 o'clock and 12 o'clock positions of the steering wheel surface according to the set number of times, at the set interval, and with the set force, wherein at the 3 o'clock position, the force direction of the force hammer is the horizontal direction, and at the 12 o'clock position, the force direction of the force hammer is the normal direction of the steering wheel surface.

[0008] Furthermore, during the test, the vehicle is parked in advance in a horizontal field where noise and vibration are controlled, the engine is turned off, the steering wheel is returned to the center, and the vehicle is parked in P gear; the acceleration sensor is pasted to the 12 o'clock position, 3 o'clock position, 6 o'clock position, 9 o'clock position and the center of the steering wheel; a force hammer is used as an excitation source, the force hammer adopts a rubber hammer head, the excitation frequency band range is 1-200Hz, a counterweight block is applied to the end of the force hammer, and the force hammer sensitivity is 2.224N / mv; the force hammer strikes the steering wheel surface at 11 o'clock, 10 o'clock and 7 o'clock positions according to the set number of times, at the set interval, and with the set force, wherein at the 11 o'clock and 10 o'clock positions, the force direction of the force hammer is the horizontal direction, and at the 7 o'clock position, the force direction of the force hammer is the normal direction of the steering wheel surface.

[0009] Furthermore, the NVH properties of commercial vehicle steering wheels are obtained based on the transfer function, including:

[0010] Determine the peak points of the transfer function, which correspond to the natural frequencies of the steering system;

[0011] The poles and residues of the transfer function are fitted as follows:

[0012]

[0013] Where N is the modal order, Ri is the residue, λ i It is the extreme point;

[0014] The pole λ obtained by fitting i Calculate damping ratio and natural frequency;

[0015] By residue R i and measured response data to estimate the mode shape vectors.

[0016] Furthermore, the extreme point λ i The form is jω i -ζ i ω i , where ζ i represents the damping ratio, ω i represents the corresponding order natural frequency, then the pole λ i The imaginary part is the corresponding order natural frequency, and the pole λ i The ratio of the real part to the imaginary part is the damping ratio.

[0017] Furthermore, through the residue R i The measured response data is used to estimate the vibration mode vector, which includes: measuring each measuring point j at the natural frequency ω i The response data y at j (ω i );

[0018] Based on the residue R obtained from the fitting i , write the following equation:

[0019] y j (ω i )=A(ω i )q ij ;

[0020] Among them, A(ω i ) is the vibration mode participation factor, q ij is the vibration mode vector q i The value at the measuring point j;

[0021] The y values ​​of all the measuring points are j (ω i )=A(ω i )q ij The combined equations are:

[0022] Y(ω i )=A(ω i )q i ;

[0023] Among them, Y(ω i ) is the natural frequency ω of all measuring points i The response vector at ;

[0024] Solve for the vibration mode vector q using the least squares method i :

[0025] q i =(A(ω i )) -1 Y(ω i );

[0026] Because the remainder is the vibration mode vector q i The conjugate transpose of, F is the natural frequency ω i The force vector at i =Y(ω i ) / R i , and regularize the obtained vibration mode vector.

[0027] Furthermore, after preprocessing the target structure, the steering wheel NVH transfer function test is first used to verify whether the steering wheel NVH properties are stable. If stable, the steering wheel NVH transfer function test is continued. Otherwise, it is detected whether the target structure with nonlinear effects is omitted and not processed.

[0028] Furthermore, the steering system defects are identified based on the obtained NVH properties of the commercial vehicle steering wheel, and the steering system design is improved.

[0029] In a second aspect, the present invention provides a commercial vehicle steering wheel NVH transfer function testing device, comprising: at least one processing unit, the processing unit, the storage unit, and the acquisition unit are interconnected through a bus unit, the storage unit stores a computer program, and when the computer program is executed by the processing unit, the commercial vehicle steering wheel NVH transfer function testing method is implemented.

[0030] In a third aspect, the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the commercial vehicle steering wheel NVH transfer function test method is implemented.

[0031] The above technical solution provided by the embodiment of the present invention has the following advantages compared with the prior art:

[0032] The present application determines the target structure with nonlinear influence on the transfer function in the steering system of a commercial vehicle, and pre-processes the target structure when testing the transfer function of the steering wheel to eliminate the nonlinear influence of the target structure on the transfer function; the transfer function test of the steering wheel of the steering system is carried out, including: setting an acceleration sensor on the steering wheel of the vehicle pre-set according to the conditions; setting the excitation source parameters, excitation, with the acceleration sensor signal as the output and the excitation signal as the input; in the transfer function fitting process, Fourier transform is performed on the input and output signals, the time domain signal is converted into a frequency domain signal, the cross-spectrum Y(ω) of the input and output signals is calculated, the auto-spectrum X(ω) of the input signal is calculated, and the frequency response function is calculated using the cross-spectrum and the auto-spectrum: H(ω)=Y(ω) / X(ω), and the transfer function is fitted by the least squares method; the NVH properties of the steering wheel of the commercial vehicle are obtained based on the transfer function. Since the target structure with nonlinear influence is eliminated, the position and amplitude of the transfer function amplitude under the same state are relatively consistent, and a stable transfer function can be effectively obtained, which provides a basis for judging the influence of the steering system structure on the NVH performance and the effectiveness of the optimization scheme. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0035] Figure 1 A flow chart of a commercial vehicle steering wheel NVH transfer function testing method provided by an embodiment of the present invention;

[0036] Figure 2 It is a schematic diagram of acceleration data measured twice in the same state when the influence of nonlinear factors is not eliminated;

[0037] Figure 3 A schematic diagram of the orientation of a steering wheel provided in an embodiment of the present invention;

[0038] Figure 4 A flow chart for obtaining the NVH properties of a commercial vehicle steering wheel based on a transfer function provided in an embodiment of the present invention;

[0039] Figure 5 A schematic diagram of a commercial vehicle steering wheel NVH transfer function testing device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0042] Example 1

[0043] like Figure 1 As shown, the technology of the present invention realizes a commercial vehicle steering wheel NVH transfer function test method, including:

[0044] Determine the target structure in the commercial vehicle steering system that has a nonlinear effect on the transfer function. When performing the steering wheel transfer function test, preprocess the target structure to eliminate the nonlinear effect of the target structure on the transfer function.

[0045] In one example, in order to meet the requirements of commercial vehicle cab flipping, the steering wheel plate system structure needs to have a telescopic structure. Usually, a telescopic shaft is designed under the steering wheel column. The telescopic shaft is a spline structure, and grease is filled in the spline groove. In the steering system, the spline structure of the shaft brings contact uncertainty, and the grease filled in the spline groove brings damping uncertainty. Figure 2 As shown in the figure, when the influence of nonlinear factors is not eliminated, even if the same vehicle is tested under the same conditions, the acceleration data will show a large difference in the location and magnitude of the amplitude. The pretreatment method for the telescopic shaft is to remove the bolts between the telescopic shaft and the universal joint of the steering system, thereby eliminating the nonlinear influence factors caused by the spline and grease of the telescopic shaft.

[0046] After eliminating the nonlinear influence of the target structure through preprocessing, the transfer function test of the steering wheel of the steering system is carried out to obtain the NVH transfer function. In one example, the transfer function test is divided into two stages. First, after preprocessing the target structure, the steering wheel NVH transfer function test is used to verify whether the NVH property of the steering wheel is stable. If it is stable, the steering wheel NVH transfer function test is continued. Otherwise, it is detected whether the target structure with nonlinear influence is omitted and not processed.

[0047] The process of transfer function testing includes:

[0048] An acceleration sensor is installed on the steering wheel of a vehicle that is pre-set according to the conditions; in the specific implementation process, the vehicle is parked in a horizontal field with controlled noise and vibration, the engine is turned off, the steering wheel is returned to the center position, and the vehicle is parked in gear P. The excitation source parameters are set, and excitation is performed, with the acceleration sensor signal as the output and the excitation signal as the input.

[0049] like Figure 3 As shown, in one example, during the test, the vehicle is parked in advance in a horizontal field with controlled noise and vibration, the engine is turned off, the steering wheel is returned to the center position, and the vehicle is parked in P gear; the acceleration sensor is pasted to the 9 o'clock and 12 o'clock positions of the steering wheel; a force hammer is used as an excitation source, the force hammer adopts a rubber hammer head, the excitation frequency band range is 1-200Hz, a counterweight block is applied to the end of the force hammer, and the force hammer sensitivity is 2.224N / mv; the force hammer strikes the 3 o'clock and 12 o'clock positions of the steering wheel surface according to the set number of times, the set interval, and the set force, wherein at the 3 o'clock position, the force direction of the force hammer is the horizontal direction, and at the 12 o'clock position, the force direction of the force hammer is the normal direction of the steering wheel surface.

[0050] In one example, during the test, the vehicle is parked in advance in a horizontal field where noise and vibration are controlled, the engine is turned off, the steering wheel is returned to the center, and the vehicle is parked in P gear; acceleration sensors are pasted to the 12 o'clock, 3 o'clock, 6 o'clock, 9 o'clock and center of the steering wheel; a force hammer is used as an excitation source, the force hammer uses a rubber hammer head, the excitation frequency band range is 1-200Hz, a counterweight block is applied to the end of the force hammer, and the force hammer sensitivity is 2.224N / mv; the force hammer strikes the steering wheel surface at 11 o'clock, 10 o'clock and 7 o'clock positions according to the set number of times, at the set interval, and with the set force, wherein at the 11 o'clock and 10 o'clock positions, the force direction of the force hammer is the horizontal direction, and at the 7 o'clock position, the force direction of the force hammer is the normal direction of the steering wheel surface.

[0051] In the above two examples, testlab is used to analyze the data. During the analysis, the direction of the accelerometer is configured according to the vehicle coordinate system, the sensitivity of the accelerometer is read, the sensitivity of the hammer is configured to 2.224N / mv, the bandwidth is set to 1024Hz, the number of spectral lines is set to 2048, and the frequency resolution is set to 0.5Hz.

[0052] The NVH transfer function is obtained by fitting the test data. During the transfer function fitting process, Fourier transform is performed on the input and output signals, the time domain signal is converted into a frequency domain signal, the cross-spectrum Y(ω) of the input and output signals is calculated, and the auto-spectrum X(ω) of the input signal is calculated. The frequency response function is calculated using the cross-spectrum and auto-spectrum: H(ω)=Y(ω) / X(ω), and finally the transfer function is fitted by the least squares method.

[0053] Obtain the NVH properties of commercial vehicle steering wheels based on transfer functions. Figure 4 As shown, the process includes:

[0054] Determine the peak points of the transfer function, which correspond to the natural frequencies of the steering system;

[0055] The poles and residues of the transfer function are fitted as follows:

[0056]

[0057] Where N is the modal order, R i is the residue, λ i It is the extreme point;

[0058] The pole λ obtained by fitting i Calculate the damping ratio and natural frequency; in the specific implementation process, the pole λ i The form is jω i -ζ i ω i , where ζ i represents the damping ratio, ω i represents the corresponding order natural frequency, then the pole λ i The imaginary part is the natural frequency of the corresponding order, and the pole λ i The ratio of the real part to the imaginary part is the damping ratio.

[0059] By residue R i The measured response data is used to estimate the vibration mode vector. i The measured response data is used to estimate the vibration mode vector, which includes: measuring each measuring point j at the natural frequency ω i The response data y at j (ω i );

[0060] Based on the residue R obtained from the fittingi , write the following equation:

[0061] y j (ω i )=A(ω i )q ij ;

[0062] Among them, A(ω i ) is the vibration mode participation factor, q ij is the vibration mode vector q i The value at the measuring point j;

[0063] The y values ​​of all the measuring points are j (ω i )=A(ω i )q ij The combined equations are:

[0064] Y(ω i )=A(ω i )q i ;

[0065] Among them, Y(ω i ) is the natural frequency ω of all measuring points i The response vector at ;

[0066] Solve for the vibration mode vector q using the least squares method i :

[0067] q i =(A(ω i )) -1 Y(ω i );

[0068] Because the remainder is the vibration mode vector q i The conjugate transpose of, F is the natural frequency ω i The force vector at q i =Y(ω i ) / R i , and regularize the obtained vibration mode vector.

[0069] The transfer function test above tests the yaw and vibration transfer functions of the steering wheel. Since the target structure with nonlinear effects is eliminated, the position and amplitude of the transfer function amplitude are relatively consistent under the same state, providing a basis for judging the impact of the steering system structure on NVH performance and providing a basis for the effectiveness of the optimization plan.

[0070] Based on the NVH properties of commercial vehicle steering wheels, steering system defects are identified and steering system design is improved. For example, when the damping ratio of the steering system is lower than the set target, some parts of the steering system are targeted to use materials with greater damping or design structures with greater damping. If the natural frequency of any order of the steering system is close to the natural frequency of the main vibration source of the commercial vehicle, such as the engine, the steering system structure is changed to change the natural frequency to avoid resonance.

[0071] Example 2

[0072] See also Figure 5 As shown, an embodiment of the present invention provides a commercial vehicle steering wheel NVH transfer function test device, including: at least one processing unit, the processing unit, the storage unit, and the acquisition unit are interconnected through a bus unit, and the storage unit is a computer-readable storage medium, which can be used to store software programs, computer executable programs, and modules, such as the software programs, computer executable programs, and modules corresponding to a commercial vehicle steering wheel NVH transfer function test method in an embodiment of the present invention. The processing unit implements the above-mentioned commercial vehicle steering wheel NVH transfer function test method by running the software programs, computer executable programs, and modules stored in the storage unit, including:

[0073] Determine the target structure in the commercial vehicle steering system that has a nonlinear effect on the transfer function, and pre-process the target structure when testing the steering wheel transfer function to eliminate the nonlinear effect of the target structure on the transfer function;

[0074] After eliminating the nonlinear influence of the target structure through preprocessing, the transfer function test of the steering wheel of the steering system is carried out, including: setting an acceleration sensor on the steering wheel of the vehicle pre-set according to conditions; setting the excitation source parameters, performing excitation, with the acceleration sensor signal as the output and the excitation signal as the input; in the transfer function fitting process, Fourier transform is performed on the input and output signals, the time domain signal is converted into a frequency domain signal, the cross-spectrum Y(ω) of the input and output signals is calculated, the auto-spectrum X(ω) of the input signal is calculated, and the frequency response function is calculated using the cross-spectrum and auto-spectrum: H(ω)=Y(ω) / X(ω), and finally the transfer function is fitted by the least squares method; the NVH properties of the commercial vehicle steering wheel are obtained based on the transfer function.

[0075] Of course, the computer program stored in the storage unit of the commercial vehicle steering wheel NVH transfer function test device provided by an embodiment of the present invention is not limited to the method operations described above, and can also execute related operations in the commercial vehicle steering wheel NVH transfer function test method provided by any embodiment of the present invention.

[0076] Example 3

[0077] An embodiment of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program. When the computer program is executed, the commercial vehicle steering wheel NVH transfer function test method is implemented, including:

[0078] Determine the target structure in the commercial vehicle steering system that has a nonlinear effect on the transfer function, and pre-process the target structure when testing the steering wheel transfer function to eliminate the nonlinear effect of the target structure on the transfer function;

[0079] After eliminating the nonlinear influence of the target structure through preprocessing, the transfer function test of the steering wheel of the steering system is carried out, including: setting an acceleration sensor on the steering wheel of the vehicle pre-set according to conditions; setting the excitation source parameters, performing excitation, with the acceleration sensor signal as the output and the excitation signal as the input; in the transfer function fitting process, Fourier transform is performed on the input and output signals, the time domain signal is converted into a frequency domain signal, the cross-spectrum Y(ω) of the input and output signals is calculated, the auto-spectrum X(ω) of the input signal is calculated, and the frequency response function is calculated using the cross-spectrum and auto-spectrum: H(ω)=Y(ω) / X(ω), and finally the transfer function is fitted by the least squares method; the NVH properties of the commercial vehicle steering wheel are obtained based on the transfer function.

[0080] A computer-readable storage medium provided in an embodiment of the present invention stores a computer program which is not limited to the method operations described above, but can also execute related operations in a commercial vehicle steering wheel NVH transfer function test method provided in any embodiment of the present invention.

[0081] In the embodiments provided by the present invention, it should be understood that the disclosed structures and methods can be implemented in other ways. For example, the structural embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, structures or units, which can be electrical, mechanical or other forms.

[0082] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0083] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0084] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A commercial vehicle steering wheel NVH transfer function test method, characterized in that: include: Determine the target structure in the commercial vehicle steering system that has a nonlinear effect on the transfer function, and pre-process the target structure when testing the steering wheel transfer function to eliminate the nonlinear effect of the target structure on the transfer function; After eliminating the nonlinear influence of the target structure through preprocessing, the transfer function test of the steering wheel of the steering system is carried out, including: setting an acceleration sensor on the steering wheel of the vehicle pre-set according to conditions; setting the excitation source parameters, performing excitation, with the acceleration sensor signal as the output and the excitation signal as the input; in the transfer function fitting process, Fourier transform is performed on the input and output signals, the time domain signal is converted into a frequency domain signal, the cross-spectrum Y(ω) of the input and output signals is calculated, the auto-spectrum X(ω) of the input signal is calculated, and the frequency response function is calculated using the cross-spectrum and auto-spectrum: H(ω)=Y(ω) / X(ω), and finally the transfer function is fitted by the least squares method; the NVH properties of the commercial vehicle steering wheel are obtained based on the transfer function.

2. The commercial vehicle steering wheel NVH transfer function test method according to claim 1, characterized in that: During the test, the vehicle is parked in advance in a horizontal field with controlled noise and vibration, the engine is turned off, the steering wheel is returned to the center, and the vehicle is parked in P gear; the acceleration sensor is pasted to the 9 o'clock and 12 o'clock positions of the steering wheel; a force hammer is used as an excitation source, the force hammer adopts a rubber hammer head, the excitation frequency band range is 1-200Hz, a counterweight block is applied to the end of the force hammer, and the force hammer sensitivity is 2.224N / mv; the force hammer strikes the 3 o'clock and 12 o'clock positions of the steering wheel surface according to the set number of times, the set interval, and the set force, wherein at the 3 o'clock position, the force direction of the force hammer is the horizontal direction, and at the 12 o'clock position, the force direction of the force hammer is the normal direction of the steering wheel surface.

3. The commercial vehicle steering wheel NVH transfer function test method according to claim 1, characterized in that: During the test, the vehicle is parked in advance in a horizontal field with controlled noise and vibration, the engine is turned off, the steering wheel is returned to the center, and the vehicle is parked in P gear; the acceleration sensor is pasted to the 12 o'clock position, 3 o'clock position, 6 o'clock position, 9 o'clock position and the center of the steering wheel; a force hammer is used as an excitation source, the force hammer adopts a rubber hammer head, the excitation frequency band range is 1-200Hz, a counterweight block is applied to the end of the force hammer, and the force hammer sensitivity is 2.224N / mv; the force hammer strikes the steering wheel surface at 11 o'clock, 10 o'clock and 7 o'clock positions according to the set number of times, at the set interval, and at the set force, wherein, at the 11 o'clock and 10 o'clock positions, the force direction of the force hammer is the horizontal direction, and at the 7 o'clock position, the force direction of the force hammer is the normal direction of the steering wheel surface.

4. The commercial vehicle steering wheel NVH transfer function test method according to claim 1, characterized in that: Obtaining the NVH properties of commercial vehicle steering wheels based on transfer functions includes: Determine the peak points of the transfer function, which correspond to the natural frequencies of the steering system; The poles and residues of the transfer function are fitted as follows: Where N is the modal order, R i is the residue, λ i It is the extreme point; The pole λ obtained by fitting i Calculate damping ratio and natural frequency; By residue R i and measured response data to estimate the mode shape vectors.

5. The commercial vehicle steering wheel NVH transfer function test method according to claim 4, characterized in that: Pole λ i The form is jω i -ζ i ω i , where ζ i represents the damping ratio, ω i represents the corresponding order natural frequency, then the pole λ i The imaginary part is the natural frequency of the corresponding order, and the pole λ i The ratio of the real part to the imaginary part is the damping ratio.

6. The commercial vehicle steering wheel NVH transfer function test method according to claim 4, characterized in that: By residue R i The measured response data is used to estimate the vibration mode vector, which includes: measuring each measuring point j at the natural frequency ω i The response data y at j (ω i ); Based on the residue R obtained from the fitting i , write the following equation: y j (oh i )=A(ω i )q ij ; Among them, A(ω i ) is the vibration mode participation factor, q ij is the vibration mode vector q i The value at the measuring point j; The y values ​​of all the measuring points are j (ω i )=A(ω i )q ij The combined equations are: Y(ω i )=A(ω i )q i ; Among them, Y(ω i ) is the natural frequency ω of all measuring points i The response vector at ; Solve for the vibration mode vector q using the least squares method i : q i =(A(ω i )) -1 Y(ω i ); Because the remainder is the vibration mode vector q i The conjugate transpose of, F is the natural frequency ω i The force vector at i =Y(ω i ) / R i , and regularize the obtained vibration mode vector.

7. The commercial vehicle steering wheel NVH transfer function test method according to claim 1, characterized in that: After preprocessing the target structure, first verify whether the steering wheel NVH properties are stable through the steering wheel NVH transfer function test. If stable, continue to perform the steering wheel NVH transfer function test. Otherwise, check whether the target structure with nonlinear effects is omitted and not processed.

8. The commercial vehicle steering wheel NVH transfer function test method according to claim 1, characterized in that: Based on the NVH properties of commercial vehicle steering wheels, steering system defects are identified and steering system design is improved.

9. A commercial vehicle steering wheel NVH transfer function test device, characterized in that: include: At least one processing unit, the processing unit, the storage unit, and the acquisition unit are interconnected through a bus unit, the storage unit stores a computer program, and when the computer program is executed by the processing unit, the commercial vehicle steering wheel NVH transfer function test method as described in any one of claims 1-8 is implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the commercial vehicle steering wheel NVH transfer function testing method according to any one of claims 1 to 8 is implemented.

Images