CN111985347A - Body-in-white modal identification method and device - Google Patents
Body-in-white modal identification method and device Download PDFInfo
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Abstract
The invention discloses a body-in-white modal identification method and a body-in-white modal identification device, wherein the identification method comprises the following steps: acquiring frequency response curves corresponding to a plurality of response points of the body-in-white to be identified after excitation is applied; splitting the frequency response curves of the plurality of response points into a real part curve combination and an imaginary part curve combination; and obtaining the identification result of the torsional mode and the bending mode of the body-in-white to be identified according to the real part curve combination and the imaginary part curve combination. The embodiment of the invention can make the body-in-white modal identification more simple and convenient.
Description
Technical Field
The invention relates to the technical field of automobile tests, in particular to a white automobile body modal identification method and a white automobile body modal identification device.
Background
The analysis of the vehicle body mode plays an important role in the field of automobile NVH. In the overall mode of the vehicle body, the first-order bending mode and the first-order torsion mode greatly contribute to low-frequency noise and vibration response. Since the body-in-white is not only the core of the vehicle body but also the foundation of the interior trim body and the entire vehicle body, the body-in-white is an important subject of research on the mode of the vehicle body. Generally, the modal frequency of the body-in-white is high, and the modal frequencies of the interior body and the entire body are also high. It is therefore important to identify and control the torsional and bending modes of the body-in-white.
The inventor of the invention finds in research that the existing white body mode identification method needs to arrange a large number of measuring points and carry out a series of numerical operations on frequency response curves of all the measuring points so as to realize the identification of the white body mode. However, the existing white body mode identification method is complex and tedious in identification process, so that the white body mode identification efficiency is low.
Disclosure of Invention
The invention provides a white body mode identification method and a white body mode identification device, which are used for solving the technical problem of low white body mode identification efficiency in the prior art and enabling white body mode identification to be simpler, more convenient and more convenient.
A first embodiment of the present invention provides a body-in-white modal recognition method, including:
acquiring frequency response curves corresponding to a plurality of response points of the body-in-white to be identified after excitation is applied;
splitting the frequency response curves of a plurality of the response points into a real part curve combination and an imaginary part curve combination;
and obtaining the identification result of the torsional mode and the bending mode of the body-in-white to be identified according to the real part curve combination and the imaginary part curve combination.
In one embodiment of the present invention, the obtaining of the identification result of the torsional mode and the bending mode of the body-in-white to be identified according to the real part curve combination and the imaginary part curve combination comprises:
when the real part curve combination meets a first preset condition and the imaginary part curve combination meets a second preset condition, judging that the white automobile body to be identified has a mode;
and after judging that the body-in-white to be identified has the mode, obtaining the identification result of the torsional mode and the bending mode of the body-in-white to be identified according to the phase direction of the imaginary part curve combination.
In one embodiment of the present invention, the first preset condition is that frequency values of all the response points exist in a preset frequency interval at the same time, and the second preset condition is that a frequency peak value of any one of the response points exists.
In one embodiment of the present invention, after determining that the body-in-white to be identified has the mode, obtaining the identification result of the torsional mode and the bending mode of the body-in-white to be identified according to the phase direction of the imaginary part curve combination includes:
identifying a frequency value when the two response points correspond to the same direction of the imaginary part curve phase in the imaginary part curve combination, and taking the frequency value as the bending mode of the body-in-white to be identified;
and identifying that the imaginary part curve phase reversal corresponding to the two response points exists in the imaginary part curve combination, and simultaneously, identifying a frequency value corresponding to the imaginary part curve phase reversal corresponding to the two response points, and taking the frequency value as the torsion mode of the body-in-white to be identified.
In one embodiment of the present invention, the splitting and combining the frequency response curves of a plurality of the response points to obtain a real part curve combination and an imaginary part curve combination includes:
splitting the frequency response curves of the plurality of response points to respectively obtain a real part curve frequency curve and an imaginary part curve frequency curve of each response point; and combining the real part curves of all the response points into a real part curve combination, and combining the imaginary part curves of all the response points into an imaginary part curve combination.
In one embodiment of the present invention, the acquiring frequency response curves corresponding to a plurality of response points of the body-in-white to be identified after the excitation is applied includes:
and arranging a corresponding sensor at each response point, and acquiring a frequency response curve generated by each sensor after the excitation is applied.
In one embodiment of the invention, the plurality of response points at least comprise a first response point, a second response point and a third response point, wherein the first response point is arranged on the left front longitudinal beam of the body-in-white to be identified, the second response point is arranged on the right front longitudinal beam of the body-in-white to be identified, and the third response point is arranged on the left rear longitudinal beam of the body-in-white to be identified.
A second embodiment of the present invention provides a body-in-white mode identifying device including:
the system comprises an acquisition module, a processing module and a control module, wherein the acquisition module is used for acquiring frequency response curves corresponding to a plurality of response points of the body-in-white to be identified after excitation is applied;
the disassembling module is used for disassembling the frequency response curves of the plurality of response points into a real part curve combination and an imaginary part curve combination;
and the identification module is used for obtaining the identification result of the torsional mode and the bending mode of the body-in-white to be identified according to the real part curve combination and the imaginary part curve combination.
In one embodiment of the present invention, the identification module is configured to:
when the real part curve combination meets a first preset condition and the imaginary part curve combination meets a second preset condition, judging that the white automobile body to be identified has a mode;
and after judging that the body-in-white to be identified has the mode, obtaining the identification result of the torsional mode and the bending mode of the body-in-white to be identified according to the phase direction of the imaginary part curve combination.
In one embodiment of the invention, the plurality of response points at least comprise a first response point, a second response point and a third response point, wherein the first response point is arranged on the left front longitudinal beam of the body-in-white to be identified, the second response point is arranged on the right front longitudinal beam of the body-in-white to be identified, and the third response point is arranged on the left rear longitudinal beam of the body-in-white to be identified.
The invention provides a white body mode identification method and a white body mode identification device, which are characterized in that frequency response curves corresponding to a plurality of response points are obtained respectively, the obtained frequency response curves are combined to obtain a real part curve combination and an imaginary part curve combination, and the white body mode is simply identified according to the phase characteristics of the real part curve combination and the imaginary part curve combination, so that the identification complexity and difficulty can be effectively reduced, and the white body mode identification efficiency can be improved.
Drawings
FIG. 1 is a schematic flow chart diagram of a body-in-white modal identification method provided by an embodiment of the invention;
FIG. 2 is a schematic diagram of a real part curve combination of frequency response curves provided by an embodiment of the present invention;
FIG. 3 is a schematic diagram of a combined imaginary curve and imaginary curve of a frequency response curve provided by an embodiment of the present invention;
fig. 4 is a detailed flowchart of step S3 of the body-in-white mode identification method according to the embodiment of the present invention;
FIG. 5 is another schematic flow chart diagram of a body-in-white modal identification method provided by an embodiment of the invention;
fig. 6 is a schematic structural diagram of a body-in-white mode identification device according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
In the description of the present application, it is to be understood that the terms "first", "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless otherwise specified.
In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.
Referring to fig. 1-5, fig. 1 shows a body-in-white mode identification method according to an embodiment of the present invention, including:
s1, acquiring frequency response curves corresponding to a plurality of response points of the body-in-white to be recognized after excitation is applied;
in the embodiment of the invention, in order to improve the identification accuracy, the body-in-white is stably placed on the air spring before the modal identification of the body-in-white is carried out, and the pressure of the air spring needs to meet the boundary condition of free modal constraint, namely 1/5-1/10 which ensures that the measured rigid body modal is smaller than a first-order elastic modal.
It is understood that the number of the response points may be plural, and for example, the present embodiment arranges a first response point, a second response point and a third response point on the body-in-white, wherein the first response point is arranged on the left front side member of the body-in-white to be identified, the second response point is arranged on the right front side member of the body-in-white to be identified, and the third response point is arranged on the left rear side member of the body-in-white to be identified. In the embodiment of the invention, the three response points are respectively provided with the acceleration sensor, and the second response point is selected as the excitation point to apply excitation, wherein the excitation applying direction is the-Z direction in the coordinate system of the whole vehicle. The embodiment of the invention applies excitation near the right front longitudinal beam of the second response point in a hammering mode, and adopts an LMS SCM205 multifunctional data acquisition system and an Impact Testing module in LMS test.
S2, splitting the frequency response curves of the multiple response points into a real part curve combination and an imaginary part curve combination;
referring to fig. 2-3, an imaginary curve combination diagram and a real curve combination diagram of a frequency response curve according to an embodiment of the invention are shown, respectively. Lab software is utilized to combine frequency response curves of a plurality of response points into a real part curve combination and an imaginary part curve combination, and the torsion mode and the bending mode of the body-in-white are judged according to the characteristics of the imaginary part curve and the real part curve, so that the torsion mode of the body-in-white can be simply and conveniently identified, and the efficiency of identifying the mode of the body-in-white is improved.
And S3, obtaining the identification result of the torsion mode and the bending mode of the body-in-white to be identified according to the real part curve combination and the imaginary part curve combination.
According to the embodiment of the invention, the frequency response curves corresponding to the multiple response points are obtained, the obtained frequency response curves are combined and disassembled to obtain the real part curve combination and the imaginary part curve combination, and the white body mode is identified according to the frequency values in the real part curve combination and the phase characteristics of the imaginary part curve combination, so that the identification complexity and difficulty can be effectively reduced, and the white body mode identification efficiency can be improved.
Referring to fig. 4, the step S3 obtains the identification result of the torsional mode and the bending mode of the body-in-white to be identified according to the real part curve combination and the imaginary part curve combination, and further includes sub-steps S31-S32:
s31, when the real part curve combination meets a first preset condition and the imaginary part curve combination meets a second preset condition, judging that the white automobile body to be identified has a mode;
as a specific implementation manner of the embodiment of the present invention, the first preset condition is that frequency values of all response points exist in a preset frequency interval at the same time, and the second preset condition is that a frequency peak value of any response point exists.
And S32, after judging that the body-in-white to be identified has the mode, obtaining the identification result of the torsional mode and the bending mode of the body-in-white to be identified according to the phase direction of the imaginary part curve combination.
In the embodiment of the present invention, it is,
as a specific implementation manner of the embodiment of the present invention, after determining that the body-in-white to be identified has the mode, obtaining the identification result of the torsional mode and the bending mode of the body-in-white to be identified according to the phase direction of the imaginary part curve combination, includes:
identifying a frequency value when two response points correspond to the same direction of the imaginary part curve phase in the imaginary part curve combination, and taking the frequency value as the bending mode of the body-in-white to be identified;
after the white automobile body to be identified is judged to have the mode, a frequency value of the imaginary part curve corresponding to the first response point and the second response point in the same direction of the phase is identified as the bending mode of the white automobile body to be identified. Continuing with fig. 2, illustratively, at a frequency of 52.3438HZ, the imaginary curves of the left and right front side rails are in phase alignment, i.e., a frequency of 52.3438HZ is the bending mode of the body-in-white to be identified.
And identifying that the phase directions of the imaginary part curves corresponding to the two response points exist in the imaginary part curve combination, and simultaneously, identifying a frequency value of the two response points corresponding to the same direction of the phase directions of the imaginary part curves, and taking the frequency value as the torsional mode of the body-in-white to be identified.
After the body-in-white to be identified has the mode, the phase reversal of the imaginary part curves corresponding to the first response point and the second response point is identified, and meanwhile, a frequency value when the phase reversal of the imaginary part curves corresponding to the second response point and the third response point is the same is used as the torsion mode of the body-in-white to be identified. Continuing to refer to fig. 3, illustratively, at a frequency of 46.0938Hz, the imaginary curve phases of the left and right front side members are reversed, and the imaginary curve phase of the right front side member is the same as the imaginary curve phase of the left rear side member, i.e., 46.0938Hz is the torsional mode of the body-in-white to be identified.
As a specific implementation manner of the embodiment of the present invention, the method for obtaining a real part curve combination and an imaginary part curve combination by splitting and combining frequency response curves of a plurality of response points includes:
splitting the frequency response curves of the multiple response points to respectively obtain a real part curve frequency curve and an imaginary part curve frequency curve of each response point; the real part curves of all the response points are combined into a real part curve combination, and the imaginary part curves of all the response points are combined into an imaginary part curve combination.
And optionally, performing a disassembling process on the frequency response curves of the plurality of response points by using LMS test.
As a specific implementation manner of the embodiment of the present invention, acquiring frequency response curves corresponding to a plurality of response points of a body-in-white to be identified after excitation application respectively includes:
and arranging a corresponding sensor at each response point, and acquiring a frequency response curve generated by each sensor after the excitation is applied.
It can be understood that the sensor arranged at each response point in the embodiment of the present invention is an acceleration sensor, and the direction of each acceleration sensor is kept consistent in order to avoid the occurrence of misjudgment and improve the reliability of identification. One response point is selected from the multiple response points to serve as an excitation point for excitation application, and optionally, a second response point arranged on the right front longitudinal beam is selected to serve as the excitation application. Illustratively, a hammer blow is applied as an excitation input near the right front rail, such that each acceleration sensor generates a corresponding frequency response curve in accordance with the applied excitation. In order to improve the identification accuracy, the selected hammer head of the force hammer applying hammering can excite all modes in the frequency band of interest, and the force spectrum cannot be greatly attenuated in the frequency range of interest; when the test is performed each time, hammering force and direction are kept consistent as much as possible, hammering is performed on the same excitation point, and hammers with poor coherence are abandoned actively in the process of multiple experiments, so that errors in data are reduced, and accuracy and reliability of identification are improved.
Optionally, in order to improve the accuracy of the obtained frequency response curve and thus improve the accuracy and reliability of identification, before data acquisition, the sensor needs to be calibrated, specifically: calibration information for all sensors (sensor model and serial number) is entered and given the appropriate channel labels (force, acceleration and voltage). Meanwhile, hammer parameter setting is carried out, and the average measuring times and the sampling frequency are set according to the measuring requirements, wherein as a specific implementation mode, the sampling frequency is set to be 512Hz, and the frequency resolution is set to be 0.5 Hz; if the input signal has noise, a force window needs to be applied; if there is leakage in the input signal, an exponential window needs to be applied.
Referring to fig. 5, another body-in-white mode identification method according to an embodiment of the present invention is shown. In order to verify the effectiveness and the practicability of the body-in-white mode identification method provided by the embodiment of the invention, the body-in-white is modeled by arranging a large number of measuring points on the body-in-white through a vibration exciter Testing method, a 28-point method is used for carrying out mode test, the excitation mode is that two vibration exciters are arranged on the right front longitudinal beam and the left rear longitudinal beam of the body-in-white for excitation, and a LMS 205 multifunctional data acquisition system and an MIMO FRF Testing module in LMS test. Referring to table 1 below, a table comparing results of a white body mode identification method according to an embodiment of the present invention and a vibration exciter test method according to the prior art is provided:
table 1: table for comparing results of test methods of embodiments and vibration exciters of the present invention
| Body-in-white mode | Examples of the invention | Vibration exciter testing method | Relative error |
| First order torsional mode | 46.0938Hz | 45.7820Hz | 0.68％ |
| First order bending mode | 52.3438Hz | 52.4030Hz | 0.11％ |
As can be seen from comparison of the results shown in table 1, the white body mode identification method provided by the embodiment of the invention is basically consistent with the conclusion obtained by the vibration exciter test method in the prior art, that is, the embodiment of the invention has effectiveness and applicability, can effectively reduce complexity and difficulty of the identification process, can simply and conveniently identify the white body mode, and is beneficial to improving the mode identification efficiency.
The embodiment of the invention has the following beneficial effects:
in the embodiment of the invention, the acceleration sensors are respectively arranged on the left front longitudinal beam, the right front longitudinal beam and the left rear longitudinal beam of the body-in-white to be identified as response points, lab software is used to combine the frequency response curves into an imaginary part curve combination and a real part curve combination by applying excitation on the right front longitudinal beam to generate frequency response curves corresponding to a plurality of response points, according to the method and the device, the bending mode and the torsion mode of the body-in-white to be identified can be identified according to the phase directions of the imaginary part curve combination and the real part curve combination, a large number of measuring points are not required to be distributed, only one acceleration sensor is arranged on the left front longitudinal beam, the right front longitudinal beam and the left rear longitudinal beam respectively to serve as a response point, the problem that the identification process is complicated and complicated due to the fact that a large number of sensors are used and vibration exciters are installed and debugged is avoided, the identification efficiency is improved, and the equipment deployment cost can be effectively.
Furthermore, the frequency values of the real part curve combination and the phase directions of the imaginary part curve combination of the frequency response curve are only used for comprehensively judging the frequencies of the bending mode and the torsion mode, so that the convenience of white body mode identification is effectively improved, the occurrence of misjudgment can be reduced, and the accuracy and the reliability of identification are improved.
Referring to fig. 6, fig. 6 illustrates a body-in-white mode identification apparatus according to an embodiment of the present invention, which includes an obtaining module 10, a detaching module 20, and an identifying module 30;
the acquiring module 10 is used for acquiring frequency response curves corresponding to a plurality of response points of the body-in-white to be identified after excitation is applied;
in the embodiment of the invention, in order to improve the identification accuracy, the body-in-white is stably placed on the air spring before the modal identification of the body-in-white is carried out, and the pressure of the air spring needs to meet the boundary condition of free modal constraint, namely 1/5-1/10 which ensures that the measured rigid body modal is smaller than a first-order elastic modal.
It is understood that the number of the response points may be plural, and for example, the present embodiment arranges a first response point, a second response point and a third response point on the body-in-white, wherein the first response point is arranged on the left front side member of the body-in-white to be identified, the second response point is arranged on the right front side member of the body-in-white to be identified, and the third response point is arranged on the left rear side member of the body-in-white to be identified. In the embodiment of the invention, the three response points are respectively provided with the acceleration sensor, and the second response point is selected as the excitation point to apply excitation, wherein the excitation applying direction is the-Z direction in the coordinate system of the whole vehicle. The embodiment of the invention applies excitation near the right front longitudinal beam of the second response point in a hammering mode, and adopts an LMS SCM205 multifunctional data acquisition system and an Impact Testing module in LMS test.
A disassembling module 20 for disassembling the frequency response curves of the plurality of response points into a real part curve combination and an imaginary part curve combination;
referring to fig. 2-3, an imaginary curve combination diagram and a real curve combination diagram of a frequency response curve according to an embodiment of the invention are shown, respectively. It should be noted that the real part curve is a real part of the average frequency response, and the imaginary part curve is an imaginary part of the average frequency response, the disassembling and assembling module 20 in the embodiment of the present invention combines the frequency response curves of the plurality of response points into a real part curve combination and an imaginary part curve combination by using LMS test.
And the identification module 30 is configured to obtain an identification result of the torsional mode and the bending mode of the body-in-white to be identified according to the real part curve combination and the imaginary part curve combination.
According to the embodiment of the invention, the frequency response curves corresponding to the multiple response points are obtained by the obtaining module 10, the obtained frequency response curves are combined by the combining module 20 to obtain the real part curve combination and the imaginary part curve combination, and the recognition module 30 recognizes the white body mode according to the frequency value in the real part curve combination and the phase characteristics of the imaginary part curve combination, so that the recognition complexity and difficulty can be effectively reduced, and the white body mode recognition efficiency can be improved.
The identification module 30 includes: the judging unit is used for judging that the white automobile body to be identified has a mode when the real part curve combination meets a first preset condition and the imaginary part curve combination meets a second preset condition;
as a specific implementation manner of the embodiment of the present invention, the first preset condition is that frequency values of all response points exist in a preset frequency interval at the same time, and the second preset condition is that a frequency peak value of any response point exists.
And the identification unit is used for obtaining the identification result of the torsional mode and the bending mode of the body-in-white to be identified according to the phase direction of the imaginary part curve combination after judging that the body-in-white to be identified has the mode.
As a specific implementation manner of the embodiment of the present invention, the identification unit is specifically configured to: and identifying a frequency value when two response points correspond to the same direction of the imaginary part curve phase in the imaginary part curve combination, and taking the frequency value as the bending mode of the body-in-white to be identified.
After the white automobile body to be identified is judged to have the mode, a frequency value of the imaginary part curve corresponding to the first response point and the second response point in the same direction of the phase is identified as the bending mode of the white automobile body to be identified. Continuing with fig. 2, illustratively, at a frequency of 52.3438HZ, the imaginary curves of the left and right front side rails are in phase alignment, i.e., a frequency of 52.3438HZ is the bending mode of the body-in-white to be identified.
And identifying that the phase directions of the imaginary part curves corresponding to the two response points exist in the imaginary part curve combination, and simultaneously, identifying a frequency value of the two response points corresponding to the same direction of the phase directions of the imaginary part curves, and taking the frequency value as the torsional mode of the body-in-white to be identified.
The identification unit is further used for identifying the phase reversal of the imaginary part curves corresponding to the first response point and the second response point after judging that the body-in-white has the mode, and simultaneously, a frequency value of the imaginary part curves corresponding to the second response point and the third response point in the same direction is used as the torsion mode of the body-in-white to be identified. Continuing to refer to fig. 3, illustratively, at a frequency of 46.0938Hz, the imaginary curve phases of the left and right front side members are reversed, and the imaginary curve phase of the right front side member is the same as the imaginary curve phase of the left rear side member, i.e., 46.0938Hz is the torsional mode of the body-in-white to be identified.
As a specific implementation manner of the embodiment of the present invention, the disassembling and assembling module 20 is specifically configured to:
splitting the frequency response curves of the multiple response points to respectively obtain a real part curve frequency curve and an imaginary part curve frequency curve of each response point; the real part curves of all the response points are combined into a real part curve combination, and the imaginary part curves of all the response points are combined into an imaginary part curve combination.
Alternatively, the disassembling module 20 utilizes LMS test. lab software to disassemble the frequency response curves of the plurality of response points to obtain a real part curve combination and an imaginary part curve combination.
As a specific implementation manner of the embodiment of the present invention, the obtaining module is specifically configured to: and arranging a corresponding sensor at each response point, and acquiring a frequency response curve generated by each sensor after the excitation is applied.
It can be understood that the sensor arranged at each response point in the embodiment of the present invention is an acceleration sensor, and the direction of each acceleration sensor is kept consistent in order to avoid the occurrence of misjudgment and improve the reliability of identification. One response point is selected from the multiple response points to serve as an excitation point for excitation application, and optionally, a second response point arranged on the right front longitudinal beam is selected to serve as the excitation application. Illustratively, a hammer blow is applied as an excitation input near the right front rail, such that each acceleration sensor generates a corresponding frequency response curve in accordance with the applied excitation. In order to improve the identification accuracy, the selected hammer head of the force hammer applying hammering can excite all modes in the frequency band of interest, and the force spectrum cannot be greatly attenuated in the frequency range of interest; when the test is performed each time, hammering force and direction are kept consistent as much as possible, hammering is performed on the same excitation point, and hammers with poor coherence are abandoned actively in the process of multiple experiments, so that errors in data are reduced, and accuracy and reliability of identification are improved.
Optionally, in order to improve the accuracy of the obtained frequency response curve and thus improve the accuracy and reliability of identification, before data acquisition, the sensor needs to be calibrated, specifically: calibration information for all sensors (sensor model and serial number) is entered and given the appropriate channel labels (force, acceleration and voltage). Meanwhile, hammer parameter setting is carried out, and the average measuring times and the sampling frequency are set according to the measuring requirements, wherein as a specific implementation mode, the sampling frequency is set to be 512Hz, and the frequency resolution is set to be 0.5 Hz; if the input signal has noise, a force window needs to be applied; if there is leakage in the input signal, an exponential window needs to be applied.
Referring to fig. 5, a flow chart of a body-in-white mode identification method according to an embodiment of the present invention is shown. In order to verify the effectiveness and the practicability of the body-in-white mode identification method provided by the embodiment of the invention, the body-in-white is modeled by arranging a large number of measuring points on the body-in-white through a vibration exciter Testing method, a 28-point method is used for carrying out mode test, the excitation mode is that two vibration exciters are arranged on the right front longitudinal beam and the left rear longitudinal beam of the body-in-white for excitation, and a LMS 205 multifunctional data acquisition system and an MIMO FRF Testing module in LMS test. Referring to table 1 below, a table comparing results of a white body mode identification method according to an embodiment of the present invention and a vibration exciter test method according to the prior art is provided:
table 1: table for comparing results of test methods of embodiments and vibration exciters of the present invention
| Body-in-white mode | Examples of the invention | Vibration exciter testing method | Relative error |
| First order torsional mode | 46.0938Hz | 45.7820Hz | 0.68％ |
| First order bending mode | 52.3438Hz | 52.4030Hz | 0.11％ |
As can be seen from comparison of the results shown in table 1, the white body mode identification method provided by the embodiment of the invention is basically consistent with the conclusion obtained by the vibration exciter test method in the prior art, that is, the embodiment of the invention has effectiveness and applicability, can effectively reduce complexity and difficulty of the identification process, can simply and conveniently identify the white body mode, and is beneficial to improving the mode identification efficiency.
The embodiment of the invention has the following beneficial effects:
in the embodiment of the invention, an acceleration sensor is respectively arranged on a left front longitudinal beam, a right front longitudinal beam and a left rear longitudinal beam of a body-in-white to be identified as a response point, an acquisition module 10 acquires a frequency response curve corresponding to a plurality of response points generated by applying excitation on the right front longitudinal beam, an assembling module 20 combines the frequency response curves into an imaginary part curve combination and a real part curve combination by using LMS test.Lab software, and an identification module 30 identifies the bending mode and the torsion mode of the body-in-white to be identified according to the frequency value of the real part curve combination and the phase direction of the real part curve combination. And the cost of equipment deployment can be effectively reduced.
Furthermore, the identification module 30 of the embodiment of the present invention only uses the frequency value of the real part curve combination and the phase direction of the imaginary part curve combination of the frequency response curve to achieve comprehensive judgment of the frequencies of the bending mode and the torsion mode, thereby effectively improving the convenience of the white body mode identification, reducing the occurrence of misjudgment, and improving the accuracy and reliability of the identification.
The foregoing is a preferred embodiment of the present invention, and it should be noted that it would be apparent to those skilled in the art that various modifications and enhancements can be made without departing from the principles of the invention, and such modifications and enhancements are also considered to be within the scope of the invention.
Claims (10)
1. A body-in-white modal identification method, comprising:
acquiring frequency response curves corresponding to a plurality of response points of the body-in-white to be identified after excitation is applied;
splitting the frequency response curves of a plurality of the response points into a real part curve combination and an imaginary part curve combination;
and obtaining the identification result of the torsional mode and the bending mode of the body-in-white to be identified according to the real part curve combination and the imaginary part curve combination.
2. The body-in-white modal identification method according to claim 1, wherein the obtaining of the identification result of the torsional mode and the bending mode of the body-in-white to be identified according to the real part curve combination and the imaginary part curve combination comprises:
when the real part curve combination meets a first preset condition and the imaginary part curve combination meets a second preset condition, judging that the white automobile body to be identified has a mode;
and after judging that the body-in-white to be identified has the mode, obtaining the identification result of the torsional mode and the bending mode of the body-in-white to be identified according to the phase direction of the imaginary part curve combination.
3. The body-in-white modal identification method according to claim 2, wherein the first preset condition is that the frequency values of all the response points are present in a preset frequency interval at the same time, and the second preset condition is that a frequency peak value of any one of the response points is present.
4. The body-in-white modal identification method according to claim 2, wherein the obtaining of the identification result of the torsional mode and the bending mode of the body-in-white to be identified according to the phase direction of the imaginary part curve combination after the determination of the body-in-white to be identified existence mode comprises:
identifying a frequency value when the two response points correspond to the same direction of the imaginary part curve phase in the imaginary part curve combination, and taking the frequency value as the bending mode of the body-in-white to be identified;
and identifying that the imaginary part curve phase reversal corresponding to the two response points exists in the imaginary part curve combination, and simultaneously, identifying a frequency value corresponding to the imaginary part curve phase reversal corresponding to the two response points, and taking the frequency value as the torsion mode of the body-in-white to be identified.
5. The body-in-white modal identification method of claim 1, wherein said splitting and combining frequency response curves of a plurality of said response points into a real part curve combination and an imaginary part curve combination comprises:
splitting the frequency response curves of the plurality of response points to respectively obtain a real part curve frequency curve and an imaginary part curve frequency curve of each response point;
and combining the real part curves of all the response points into a real part curve combination, and combining the imaginary part curves of all the response points into an imaginary part curve combination.
6. The body-in-white modal identification method according to claim 1, wherein the obtaining of the frequency response curve corresponding to each of the plurality of response points of the body-in-white to be identified after the excitation is applied comprises:
and arranging a corresponding sensor at each response point, and acquiring a frequency response curve generated by each sensor after the excitation is applied.
7. The body-in-white modal identification method according to claim 1, wherein the plurality of response points includes at least a first response point, a second response point and a third response point, wherein the first response point is disposed on a left front side member of the body-in-white to be identified, the second response point is disposed on a right front side member of the body-in-white to be identified, and the third response point is disposed on a left rear side member of the body-in-white to be identified.
8. A body-in-white modal recognition device, comprising:
the system comprises an acquisition module, a processing module and a control module, wherein the acquisition module is used for acquiring frequency response curves corresponding to a plurality of response points of the body-in-white to be identified after excitation is applied;
the disassembling module is used for disassembling the frequency response curves of the plurality of response points into a real part curve combination and an imaginary part curve combination;
and the identification module is used for obtaining the identification result of the torsional mode and the bending mode of the body-in-white to be identified according to the real part curve combination and the imaginary part curve combination.
9. The body-in-white modal identification device of claim 8, wherein the identification module is to:
when the real part curve combination meets a first preset condition and the imaginary part curve combination meets a second preset condition, judging that the white automobile body to be identified has a mode;
and after judging that the body-in-white to be identified has the mode, obtaining the identification result of the torsional mode and the bending mode of the body-in-white to be identified according to the phase direction of the imaginary part curve combination.
10. The body-in-white modal identification device of claim 8, wherein the plurality of response points comprises at least a first response point, a second response point, and a third response point, wherein the first response point is disposed on a left front side member of the body-in-white to be identified, the second response point is disposed on a right front side member of the body-in-white to be identified, and the third response point is disposed on a left rear side member of the body-in-white to be identified.
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