Method for identifying contribution of vehicle suspension paths to road noise in vehicle interior based on transfer function test

Abstract

The application discloses a kind of based on transfer function test's automobile suspension path to the identification method of contribution of road noise in vehicle, comprising the following steps: S1, dynamic parameter identification;S2, static test, obtains the acoustic transfer function curve of excitation force at the knuckle of vehicle to the ear of front row and rear row in vehicle;S3, the acoustic transfer function curve obtained is compared and analyzed, and the contribution of road noise peak value of vehicle suspension is identified.This application based on transfer function test's automobile suspension path to the identification method of contribution of road noise in vehicle, can identify the contribution of road noise of suspension to automobile, and efficiently and accurately lock the key path for road noise optimization.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of automobiles, and in particular, the present application relates to a method for identifying the contribution of the suspension path of an automobile to the road noise in the vehicle based on a transfer function test. BACKGROUND

[0002] Road noise refers to the vibration and noise generated by the interaction of the tire and the road surface, such as collision and friction, during the driving of the automobile, which is transmitted through the suspension and causes the occupants in the cabin to perceive the noise inside the vehicle, with the main frequency concentrated in 20-300Hz, which is one of the most important noises of the automobile. For the rapidly developing new energy vehicles at present, the road noise has become the most concerned NVH problem further after the masking effect of the engine noise is lacking.

[0003] The suspension system / component, as a connecting structure, together with the tire constitutes four transmission paths of the road noise. Since the number of automobile suspension components is large, the structure is complex, and the degree of mutual coupling is high, therefore, in the improvement work of the road noise of the automobile, it is necessary to identify the contribution of each suspension path to the noise in the vehicle, and to compare the peak values of each contribution path based on the frequency domain, identify the highest peak path, and then find out the most critical path, which is the key work for efficiently improving the road noise.

[0004] The existing method for judging the contribution of the boundary suspension of the whole vehicle to the road noise is to simultaneously reduce the tire pressure of the two front wheels / two rear wheels to obtain the change of the road noise. This method is relatively rough, and its disadvantages are as follows:

[0005] 1. Due to the need for stable driving, it is not possible to reduce the tire pressure of a single tire, and simultaneously reducing the tire pressure of the two front wheels / two rear wheels can only lock the contribution to 1 / 2 suspension (front suspension or rear suspension), and cannot lock to 1 / 4 suspension (single suspension);

[0006] 2. The scheme of simultaneously reducing the tire pressure of the two front wheels / two rear wheels will make the state of the tire inconsistent with the actual situation, cannot reflect the actual working state of the tire, and the road noise performance is different from the actual situation; 3. The scheme of simultaneously reducing the tire pressure of the two front wheels / two rear wheels will make the attitude of the whole vehicle and the suspension components abnormal, the compression state of the suspension elastic components is inconsistent with the actual vehicle, and the problem cannot be accurately reproduced.

[0007] Compared with the test method of the interior body noise transmission path disclosed in the patent document with publication number CN110487560A, the method is based on the contribution analysis of the interior body panel, does not involve the whole vehicle / suspension system, and is not a method for evaluating the whole vehicle boundary road noise; compared with the suspension system loading system and loading method under the simulated real vehicle driving condition disclosed in the patent document with publication number CN114354226A, the method is aimed at the loading method of the suspension after removing the tire, is not the whole vehicle boundary, and does not use the analysis method of the transfer function. Moreover, since the tire is removed, the method is not used to evaluate the whole vehicle road noise, because the tire, as an important component of the suspension system, has very rich stiffness and modal itself, which is an important factor affecting the road noise, and the market silent noise reduction tire is developed based on this demand. SUMMARY

[0008] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application provides a method for identifying the contribution of the suspension path of a vehicle to the road noise in the vehicle based on transfer function testing, which aims to identify the contribution of the suspension to the road noise of the vehicle and efficiently and accurately lock the key path for road noise optimization.

[0009] In order to solve the above technical problems, the technical scheme adopted by the present application is: a method for identifying the contribution of the suspension path of a vehicle to the road noise in the vehicle based on transfer function testing, comprising the steps of:

[0010] S1, dynamic parameter identification;

[0011] S2, static test, obtaining the acoustic transfer function curve from the excitation force at the steering knuckle of the vehicle to the ears of the front and rear passengers;

[0012] S3, comparing and analyzing the obtained acoustic transfer function curve to identify the contribution of the vehicle suspension to the road noise peak value.

[0013] In the step S1, the whole vehicle boundary, the vibration amplitude level in the X, Y and Z directions of the four wheel centers of the vehicle under the rough road condition is identified and recorded, the vibration amplitude curve at each point in the frequency domain is taken as the output excitation source signal of the exciter at that point, which is equivalent to road spectrum excitation, and is the same as the real vehicle road noise excitation input; the noise at the front and rear ears of the vehicle under the rough road condition and the vehicle speed is obtained, and the frequency corresponding to the main problem peak value is identified as the objective data for subsequent problem analysis and research.

[0014] The step S1 comprises:

[0015] S11, vehicle state setting;

[0016] S12, vehicle operation data acquisition.

[0017] The step S12 comprises:

[0018] S1201, measurement point definition;

[0019] S1202, parameter setting;

[0020] S1203, working condition definition;

[0021] S1204, data processing.

[0022] In the step S1201, the vibration measurement point is set at the middle part of the steering knuckle, the noise measurement points are set as two microphones arranged respectively at the outer ears of the driver and the right rear passenger, the seat back of the vehicle is adjusted to the vertical state, and the height of the microphone is ensured to be 0.7±0.02 meters from the center line to the seat surface.

[0023] In the step S1203, the road noise and the hub vibration of the vehicle are tested under the boundary of the full load and the empty load of the whole vehicle, on the rough road surface and at the vehicle speed of interest, and the frequency domain data are reserved.

[0024] In the step S1204, the results of the step S1202 and the results of the step S1203 are subjected to 20-300Hz band-pass filtering processing, the data are refined, and the typical rough road section problem frequencies are reserved.

[0025] The step S2 comprises:

[0026] S21, using the exciter to excite all suspensions of the vehicle at the same time, considering the mutual coupling of all suspensions working at the same time;

[0027] S22, using the exciter to excite one suspension at the front axle and one suspension at the rear axle at the same time, considering the mutual coupling of the two suspension paths of the front axle and the rear axle;

[0028] S23, using the exciter to excite the single suspensions one by one, and collecting the responses, to refine and decompose the problems to the single suspension path.

[0029] The step S3 comprises:

[0030] S31, identifying the road noise peak value, recording and identifying the noise peak value corresponding frequencies as F1, F2...Fn;

[0031] S32, comparing the transfer function curve in the step S31 with all the transfer function curves obtained in the first excitation working condition based on the frequency domain, identifying the corresponding conditions based on F1, F2...Fn, and selecting the first three transfer function curves according to the amplitude order;

[0032] S33, compare the three transfer function curves ranked first in step S32 with all the transfer function curves obtained under the second excitation condition based on the frequency domain, identify the corresponding conditions based on F1, F2,..., Fn, and select the three transfer function curves with the largest amplitude as the first three transfer function curves;

[0033] S34, compare the three transfer function curves ranked first in step S33 with all the transfer function curves obtained under the third excitation condition based on the frequency domain, identify the corresponding conditions based on F1, F2,..., Fn, and select the three transfer function curves with the largest amplitude as the first three transfer function curves.

[0034] The automobile suspension path contribution amount identification method based on the transfer function test can identify the contribution amount of the suspension to the road noise of the automobile, and efficiently and accurately lock the key path for road noise optimization. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 is a flowchart of the automobile suspension path contribution amount identification method based on the transfer function test of the present application;

[0036] Figure 2 is a schematic diagram of the excitation position;

[0037] The marks in the above figures are as follows: 1, tire assembly; 2, wheel hub; 3, force sensor; 4, exciter; 5, support. DETAILED DESCRIPTION

[0038] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings, in which several embodiments of the present application are given. However, the present application can be realized in different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terminology used in the description of the present application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0040] As shown in Figure 1 The present application provides an automobile suspension path contribution amount identification method based on a transfer function test, which comprises the following steps:

[0041] S1, dynamic parameter identification;

[0042] S2, static test, obtain the acoustic transfer function curve of the excitation force at the vehicle steering knuckle to the front and rear ears in the vehicle;

[0043] S3, comparative analysis of the obtained acoustic transfer function curve, and identifying the contribution of the vehicle suspension to the road noise peak value.

[0044] Specifically, the present application provides a method for identifying the contribution of the suspension to the road noise of the vehicle, and the main innovation points are as follows: 1. Frequency selection: for the problem of low-frequency noise on rough roads, the selected frequency is 20-300Hz, and the problem is accurately located; 2. Amplitude selection: the suspension is a nonlinear system, and the response is different under different excitation amplitudes, so the wheel hub vibration level under the actual vehicle operating condition is used as the excitation amplitude; 3. Hardware selection: conventional NVH test hardware is used, including exciter, vibration acceleration sensor and microphone, which is easy to obtain and has high universality; 4. Test operation: hierarchical test is carried out, and the contribution of each level of suspension (full suspension, front & rear 1 / 2 suspension and 1 / 4 suspension) is determined one by one. The specific operation is to apply the exciter to excite the 20-300Hz signal to the full suspension, front & rear 1 / 2 suspension and 1 / 4 suspension path respectively, which can identify the contribution of single path and consider the mutual coupling of 2 / 4 and 4 / 4 suspension running at the same time; 5. The excitation input consistent with the road noise is the corresponding amplitude of each loading point under the rough road condition based on the frequency domain (equivalent to the road spectrum), and the response signal is picked up at the same time, which is the same as the actual vehicle road noise excitation input, and is more conducive to problem reproduction and troubleshooting. 5. Design analysis program: compare the test data with the actual road noise signal in the frequency domain, identify the noise peak points with the same frequency, and then lock the key path according to the amplitude level of the peak points, identify the correlation between the front axle, rear axle and each suspension and the road noise in the vehicle, so as to efficiently identify and control the source of road noise.

[0045] In the above step S1, the vehicle boundary is identified and recorded, and the vibration amplitude level of the vehicle wheel hub X, Y and Z directions based on the frequency domain under the rough road condition is recorded, the vibration amplitude curve based on the frequency domain at each point is taken as the output excitation source signal of the exciter at this point, which is equivalent to road spectrum excitation, and is the same as the actual vehicle road noise excitation input; the noise at the front and rear ears in the vehicle under the rough road condition and speed is obtained, and the frequency corresponding to the main problem peak value is identified as the objective data for subsequent problem analysis and research. The coordinate system is the vehicle coordinate system, the X direction is the longitudinal direction of the vehicle, the Y direction is the transverse direction of the vehicle, and the Z direction is the vertical direction.

[0046] The above step S1 includes:

[0047] S11, vehicle state setting;

[0048] S12, vehicle operating data acquisition.

[0049] In the above step S11, the vehicle is parked, and the vehicle boundary is closed. The vehicle opening position is in the normal driving condition (the door / window / sunroof / air conditioner outside circulating air inlet should be normally closed). The vehicle is loaded and unloaded by the torso weight dummy, and the test and analysis are carried out respectively.

[0050] The above step S12 includes:

[0051] S1201, definition of measuring point;

[0052] S1202, parameter setting;

[0053] S1203, working condition definition;

[0054] S1204, data processing.

[0055] In the above step S1201, the vibration measuring point is set at the middle position of the steering knuckle, which is beneficial to the arrangement of the exciter. The noise measuring point is set as 2 microphones arranged at the driver's outer ear and the right rear passenger's outer ear respectively, the vehicle seat backrest is adjusted to the vertical state, and the height of the microphone is ensured to be 0.7±0.02 meters from the center line to the chair surface.

[0056] In the above step S1202, the vibration and noise collection is set as follows: time length 20 seconds, resolution 1 Hz, 10 times average / second; all sensors are calibrated according to the conventional requirements.

[0057] In the above step S1203, the vehicle road noise and wheel hub vibration are tested under the boundary of the unloaded and full-loaded vehicle, the rough road surface and the vehicle speed concerned, and the frequency domain data is reserved. (If there is no obvious difference between the unloaded and full-loaded vehicle vibration and noise, either of them can be selected as the output result).

[0058] In the above step S1204, the results of step S1203 are subjected to 20-300Hz band-pass filtering processing, the data is refined, the typical rough road problem frequency is reserved, and the analysis efficiency is improved.

[0059] The above step S2 includes:

[0060] S21, using the exciter to excite all suspensions of the vehicle at the same time, the excitation position is located at the wheel hub point of the four wheels of the vehicle, the four wheels are respectively installed on the four suspensions, and the mutual coupling of all suspensions working at the same time is considered;

[0061] S22, using the exciter to excite one suspension at the front axle and one suspension at the rear axle respectively at the same time, considering the mutual coupling of the front and rear suspension paths; and first using two exciters to excite the wheel centers of the two front wheels and collect the responses; then using two exciters to excite the wheel centers of the two rear wheels and collect the responses;

[0062] S23, using the exciter to excite the single suspension one by one and collect the responses, and decompose the problem to the single suspension path.

[0063] In the above steps S21, S22 and S23, the excitation is along the X, Y and Z directions in the vehicle coordinate system. The vehicle is in a stationary state, and the wheel center is excited along the X, Y and Z directions in the vehicle coordinate system,

[0064] In the above steps S21, S22 and S23, the excitation signal needs to be defined: under the boundary of the vehicle empty / full load, the vibration curves of the three directions in the frequency domain measured at the knuckle of each suspension are taken as the input signals of the exciter, which are input to the corresponding suspension for excitation, which is equivalent to applying road spectrum excitation. The same as the real vehicle road noise excitation input, it is more conducive to problem reproduction and troubleshooting.

[0065] In the above steps S21, S22 and S23, the excitation condition needs to be defined: under the vehicle coordinate system, the X, Y and Z directions of the full suspension, front & rear 1 / 2 suspension and 1 / 4 suspension are excited by the exciter at a frequency of 20-300Hz. The excitation position is as close as possible to the acceleration sensor arrangement position, and the definition is shown in Figure 2 , the excitation sequence and data collection definition is shown in Table 1.

[0066] Table 1 Excitation sequence and data collection definition

[0067]

[0068] The above step S21 is set as the first excitation condition, and the four suspensions of the vehicle (including the two front suspensions arranged on the front axle of the vehicle and the two rear suspensions arranged on the rear axle of the vehicle) are excited at the same time. The response position is set at the outer ear of the driver and the right rear passenger (the right rear passenger refers to the passenger located at the right side of the driver) on the vehicle. The collected data includes the noise transfer function curves of each suspension excitation point to the in-vehicle response position. One excitation is performed, and a total of 24 transfer function curves are obtained. The target is to obtain the overall transfer function data under the mutual coupling of all suspensions.

[0069] The step S22 is set as the second excitation mode, and one front suspension and one rear suspension of the vehicle are excited, the response position is set as the outer ear of the driver and the outer ear of the right rear passenger on the vehicle, the collected data includes the noise transfer function curves from the front and rear excitation points to the response position in the vehicle, and the front suspension is excited twice to obtain 12 transfer function curves, and the rear suspension is excited twice to obtain 12 transfer function curves, and the target is to obtain the overall transfer function data of the front suspension and the rear suspension under the coupling condition.

[0070] The step S23 is set as the third excitation mode, and each suspension of the vehicle is excited separately, the response position is set as the outer ear of the driver and the outer ear of the right rear passenger on the vehicle, the collected data includes the noise transfer function curves from each suspension excitation point to the response position in the vehicle, and a total of 4 excitations are performed to obtain 24 transfer function curves, and the target is to obtain the single wheel hub transfer function data.

[0071] In the steps S21, S22 and S23, the data collection needs to be defined: the excitation duration is set to 20 seconds, the resolution is 1 Hz, the rectangular window is applied to the input and output, the acoustic transfer function curves from the steering knuckle excitation force to the front and rear human ears in the vehicle are obtained, and the curve form is: the horizontal axis is the frequency; the vertical axis is the sound pressure level / input force (Pa / N).

[0072] In the step S2, the acoustic transfer function curves from the steering knuckle excitation force to the front and rear human ears in the vehicle are finally obtained, and the curve form is: the horizontal axis is the frequency; the vertical axis is the sound pressure level / input force (Pa / N).

[0073] In the step S3, the obtained transfer function curves are compared based on the frequency domain, the road noise is taken as the target curve, at the peak value of any corresponding frequency, the amplitude of each transfer function curve is compared, the contribution of each suspension to the road noise peak value is identified, the position with larger amplitude has larger contribution, and is taken as the key path for investigation.

[0074] The step S3 includes:

[0075] S31, identify the road noise peak value, record and identify the noise peak value corresponding frequency as F1, F2...Fn; the target is to confirm the problem and mark the peak value corresponding frequency;

[0076] S32, compare the transfer function curve in the step S31 and all the transfer function curves obtained in the first excitation mode based on the frequency domain, identify the corresponding condition based on F1, F2...Fn, and select the first three transfer function curves according to the amplitude; the target is to identify the road noise problem caused by the common coupling operation of the four suspensions;

[0077] S33, comparing the three transfer function curves ranked first in step S32 with all the transfer function curves obtained under the second excitation condition based on the frequency domain, identifying corresponding conditions based on F1, F2,..., Fn, and selecting the three transfer function curves with the largest amplitude; the target is to further decompose the road noise problem corresponding to the overall suspension into the front and rear suspensions;

[0078] S34, comparing the three transfer function curves ranked first in step S33 with all the transfer function curves obtained under the third excitation condition based on the frequency domain, identifying corresponding conditions based on F1, F2,..., Fn, and selecting the three transfer function curves with the largest amplitude; the target is to further decompose the road noise problem corresponding to the front and rear suspensions into a single suspension, and the three transfer function curves in this step are the most critical paths for the road noise problem at the identified frequency.

[0079] After identifying the three critical paths associated with the road noise problem, the complex problem can be simplified for processing in a conventional manner, and ordinary test personnel can use conventional test methods to confirm the problem, such as using the mass disturbance method / structural reinforcement method, to perform targeted optimization.

[0080] The application has been described above with reference to the drawings, and it is obvious that the specific implementation of the application is not limited by the above method. Any non-essential improvement or direct application of the inventive concept and technical solution to other occasions without modification is within the protection scope of the application.

Claims

1. A method for identifying the contribution of the paths of a vehicle suspension to road noise in the vehicle cabin based on a transfer function test, characterized in that The method comprises the steps of: S1, dynamic parameter identification; S2, static test, obtaining the acoustic transfer function curve of the excitation force at the steering knuckle of the vehicle to the ears of the front and rear passengers in the vehicle; S3, comparing and analyzing the obtained acoustic transfer function curve to identify the contribution of the vehicle suspension to the road noise peak value; Wherein, the step S2 comprises: S21, using the exciter to excite all suspensions of the vehicle at the same time, considering the mutual coupling of all suspensions working at the same time; S22, using the exciter to excite one suspension at the front axle and one suspension at the rear axle at the same time, considering the mutual coupling of the front and rear axle suspension paths; S23, using the exciter to excite each single suspension one by one, and collecting the response, and refining and decomposing the problem to a single suspension path; The step S3 comprises: S31, identifying the road noise peak value, recording and identifying the noise peak value corresponding frequency as F1, F2...Fn; S32, comparing the transfer function curve in step S31 with all the transfer function curves obtained in the first excitation condition based on frequency domain, identifying the corresponding condition based on F1, F2...Fn, and selecting the top 3 transfer function curves according to amplitude; S33, comparing the top 3 transfer function curves in step S32 with all the transfer function curves obtained in the second excitation condition based on frequency domain, identifying the corresponding condition based on F1, F2...Fn, and selecting the top 3 transfer function curves according to amplitude; S34, comparing the top 3 transfer function curves in step S33 with all the transfer function curves obtained in the third excitation condition based on frequency domain, identifying the corresponding condition based on F1, F2...Fn, and selecting the top 3 transfer function curves according to amplitude.

2. The method of claim 1, wherein In the step S1, the vibration amplitude level of the wheel center X, Y, Z direction based on frequency domain of the four wheels of the vehicle under the rough road condition is identified and recorded, the vibration amplitude curve based on frequency domain at each point is taken as the output excitation source signal of the exciter at the point, which is equivalent to road spectrum excitation, and the same as the input of real vehicle road noise excitation; the noise at the front and rear ears in the vehicle under the rough road condition and vehicle speed is obtained, and the frequency corresponding to the main problem peak value is identified as the objective data for subsequent problem analysis and research.

3. The method of claim 1, wherein The step S1 comprises: S11, vehicle state setting; S12, vehicle operation data collection.

4. The method of claim 3, wherein The step S12 comprises: S1201, measurement point definition; S1202, parameter setting; S1203, working condition definition; S1204, data processing.

5. The transfer function test based method for identifying the contribution of the suspension paths to the road noise in the vehicle cabin of claim 4, wherein, In the step S1201, the vibration measurement point is set at the middle part of the steering knuckle, the noise measurement points are set as two microphones arranged at the outer ear of the driver and the outer ear of the right rear passenger respectively, the vehicle seat backrest is adjusted to the vertical state, and the height of the microphone is ensured to be 0.7±0.02 meters from the center line to the seat surface.

6. The transfer function test based method for identifying the contribution of the suspension paths to the road noise in the vehicle cabin of claim 4, wherein, In the step S1203, the vehicle road noise and wheel center vibration are tested under the rough road and vehicle speed under the full load boundary of the vehicle, and the frequency domain data is retained.

7. The transfer function test based method for identifying the contribution of the suspension paths to the road noise in the vehicle cabin of claim 4, wherein, In the step S1204, the result of the step S1202 is subjected to 20-300 Hz band-pass filtering processing with the result of the step S1203, to refine the data and to retain the typical rough road section problem frequency.

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