Torsional mode identification method, system and device and computer readable storage medium

Abstract

A torsional mode identification method, system and device and a computer readable storage medium belong to the technical field of auxiliary frame development, and the method comprises the following steps: selecting a reference point on an auxiliary frame, applying unit load excitation to the reference point, collecting an IPI curve at the reference point, and extracting a response frequency corresponding to a first acceleration peak value in the IPI curve as a torsional mode frequency. According to the method, the reference point is selected on the auxiliary frame, the unit load excitation is applied to the reference point, when the dynamic stiffness of the reference point is minimum, the torsional mode appears under the action frequency, and due to the fact that the dynamic stiffness is inconvenient to measure directly and is in negative correlation with the acceleration response, the IPI curve at the reference point is collected, and the dynamic stiffness of the auxiliary frame is accurately measured. The response frequency corresponding to the first acceleration peak value in the curve is found out, the acceleration peak position corresponds to the dynamic stiffness trough position, the response frequency is the modal frequency when the dynamic stiffness is minimum, namely the torsional mode appears, and the torsional mode can be recognized only by collecting the IPI curve in a short time, so that the recognition efficiency is improved.

Description

Technical Field

[0001] The present application relates to the field of subframe development, and in particular to a torsional mode identification method, system, device and computer-readable storage medium. Background Art

[0002] The subframe is an important component connecting the body and chassis, and is part of the suspension system. The subframe is equipped with a steering gear, swing arm, power suspension, and stabilizer bar. The steering gear is used to control the steering of the body, the swing arm is used to control the swing amplitude of the tire, the power suspension is used for power output, and the stabilizer bar is used to prevent the vehicle from tilting due to inconsistent rotation speeds of the two tires when turning. The steering gear, swing arm, and stabilizer bar all belong to the chassis, and the power suspension belongs to the powertrain.

[0003] The vibration of the chassis and powertrain is transmitted into the vehicle through the subframe. The NVH (Noise, Vibration, Harshness) performance of the subframe is crucial to the NVH performance of the entire vehicle, and the torsional mode of the subframe is a key indicator of NVH performance.

[0004] In subframe development, due to changes in surrounding environmental parts and iterative modal optimization, a large number of subframe solutions often require repeated analysis of subframe modes. How to quickly and efficiently identify torsional modes in subframe forward development is particularly important for accelerating the subframe NVH development cycle.

[0005] Prior art 1 discloses a design method for a vehicle aluminum alloy subframe and a vehicle, wherein the scheme includes judging whether the preset first welding process requirement is met according to the welding-related parameters of the current subframe, and if so, entering the second step; analyzing the material mechanical properties of the subframe to judge whether: at the vibration frequency of all vehicle speeds, whether the subframe mode meets the preset first frequency, and whether the subframe meets the collision requirement, and if so, completing the subframe design, and if not, adjusting the structure of the subframe and re-entering step 1 until a structure that meets the preset requirements of the two steps is designed. The scheme does not disclose an analysis method for judging whether the subframe mode meets the first frequency.

[0006] Prior art 2 discloses a fully constrained layer-by-layer evaluation and forward development of a subframe, and its scheme includes a first-layer evaluation and forward development: fully constraining the four corner bushings to obtain the first-layer subframe frame mode f1; forward development and optimization of the sheet metal thickness of the subframe frame; a second-layer evaluation and forward development: fully constraining the bushings connecting the swing arm to obtain the second-layer subframe and the mode f2 of the connecting swing arm; forward development and optimization of the subframe and swing arm modes; a third-layer evaluation and forward development: fully constraining the bushings connecting the stabilizer bar to obtain the third-layer subframe, swing arm and stabilizer bar mode f3; forward development and optimization of the subframe, swing arm and stabilizer bar modes; a fourth-layer evaluation and forward development: fully constraining the steering machine and dynamic total suspension to obtain the fourth-layer subframe, swing arm, stabilizer bar and steering machine / dynamic total suspension mode f4; forward development and optimization of the subframe, swing arm, stabilizer bar, steering machine / dynamic total suspension modes. This solution focuses on evaluating and developing the modes of each layer of the subframe, and does not disclose how to quickly identify and optimize the modes of the first layer of the subframe. Summary of the invention

[0007] The present application provides a torsional mode recognition method, system, device and computer-readable storage medium, which can solve the technical problem in the prior art that torsional mode recognition of a subframe is time-consuming and inefficient.

[0008] In a first aspect, an embodiment of the present application provides a torsional mode recognition method, the torsional mode recognition method comprising:

[0009] Select a reference point on the subframe and apply unit load excitation at the reference point;

[0010] The origin acceleration admittance IPI curve at the reference point is collected, and the response frequency corresponding to the first acceleration peak in the IPI curve is extracted as the torsional modal frequency.

[0011] In combination with the first aspect, in one implementation, the reference point is a position point with a maximum torsional vibration amplitude.

[0012] In combination with the first aspect, in one implementation, the reference point is a corner point or a connection point on the subframe connected to the vehicle body.

[0013] In combination with the first aspect, in one implementation, the number of the reference point is at least one;

[0014] After averaging the response frequencies of all reference points, the average frequency obtained is the torsional mode frequency.

[0015] In combination with the first aspect, in one implementation, the greater the stiffness of the subframe, the higher the upper limit of the action frequency range of unit load excitation.

[0016] In combination with the first aspect, in one implementation, the action frequency range of the unit load excitation is 0-200 Hz.

[0017] In combination with the first aspect, in one implementation, the action direction of the unit load excitation is applied to the reference point along the Z direction of the vehicle body coordinate system.

[0018] In a second aspect, an embodiment of the present application provides a torsional mode recognition system, the torsional mode recognition system comprising:

[0019] An action module, which is used to select a reference point on the subframe and apply a unit load excitation at the reference point;

[0020] The data processing module is used to collect the origin acceleration admittance IPI curve at the reference point, and extract the response frequency corresponding to the first acceleration peak in the IPI curve as the torsional modal frequency.

[0021] In a third aspect, an embodiment of the present application provides a torsional mode recognition device, which includes a processor, a memory, and a torsional mode recognition program stored in the memory and executable by the processor, wherein when the torsional mode recognition program is executed by the processor, the steps of the torsional mode recognition method are implemented.

[0022] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, on which a torsional mode recognition program is stored, wherein when the torsional mode recognition program is executed by a processor, the steps of the torsional mode recognition method are implemented.

[0023] The beneficial effects brought by the technical solution provided in the embodiments of the present application include:

[0024] By selecting a reference point on the subframe and applying a unit load excitation at the reference point, when the dynamic stiffness of the reference point is minimum, it means that a torsional mode has appeared at this action frequency. Since the dynamic stiffness is inconvenient to measure directly, and the dynamic stiffness is negatively correlated with the acceleration response, the IPI curve at the reference point is collected, and the response frequency corresponding to the first acceleration peak in the curve is found. The acceleration peak corresponds to the dynamic stiffness trough, and the response frequency is the modal frequency when the dynamic stiffness is minimum, that is, when the torsional mode appears. It only takes a short period of time to collect the IPI curve to identify the torsional mode, thereby improving the identification efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a flow chart of an embodiment of a torsional mode identification method of the present application;

[0026] Figure 2 This is a schematic diagram of an IPI curve in a specific embodiment of a torsional mode identification method of the present application;

[0027] Figure 3This is a schematic diagram of the position of reference points in a specific embodiment of the torsional mode identification method of the present application;

[0028] Figure 4 This is a schematic diagram of functional modules of an embodiment of a torsional mode identification system of the present application;

[0029] Figure 5 This is a schematic diagram of the hardware structure of the torsional mode recognition device involved in the embodiment of the present application. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0031] First, some technical terms in the present application are explained to facilitate those skilled in the art to understand the present application.

[0032] Torsional modes are the torsional vibrations of a structure around its axis when it is subjected to external excitation. In automotive engineering, torsional modal analysis studies the vibration characteristics of components such as engines, gearboxes, and drivetrains under specific operating conditions. For example, the fourth-order mode is characterized by the gearbox and drive shaft torsion in the opposite direction to the engine, and the drive shaft rotation angle amplitude is large, which usually causes low-frequency roar problems in the car. In body-in-white (BIW) analysis, the overall torsional mode is important because it affects the NVH (noise, vibration and harshness) performance of the vehicle.

[0033] Frequency response analysis refers to applying a specific known excitation force to excite the structure in a controllable manner, while measuring the input and output signals, and analyzing and finding the dynamic parameters of the structure to evaluate its dynamic characteristics or establish a mathematical model. The results of frequency response analysis are generally expressed as frequency-response curves, including amplitude-frequency curves, phase-frequency curves, real frequency curves and imaginary frequency curves, or vector end trajectory diagrams of response vectors.

[0034] Dynamic stiffness refers to the ability of a structure to resist deformation under specific dynamic excitation. Dynamic stiffness is an important indicator to measure the ability of a structure to resist predetermined dynamic excitation, and is mainly used to describe the vibration reduction performance of the structure. The definition of dynamic stiffness can be further explained as: the ratio of the change in pressure (or tensile force) on the structure to the change in displacement within a certain displacement range and at a certain frequency. The test method includes loading and unloading tests within a specific frequency and displacement range, recording and analyzing the dynamic response of the material, and obtaining the dynamic stiffness value.

[0035] The origin acceleration admittance that reflects the dynamic stiffness characteristics of the connection point is called IPI. IPI stands for Input Point Inertance, which refers to the acceleration admittance and represents the transfer function between the acceleration response and the excitation force.

[0036] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0037] In a first aspect, an embodiment of the present application provides a torsional mode identification method.

[0038] In one embodiment, referring to Figure 1 , Figure 1 This is a flow chart of the first embodiment of the torsional mode identification method of the present application. Figure 1 As shown, the torsional mode identification method includes:

[0039] Step S1: Select a reference point on the subframe and apply a unit load excitation at the reference point.

[0040] Step S2, collecting the origin acceleration admittance IPI curve at the reference point, and extracting the response frequency corresponding to the first acceleration peak in the IPI curve as the torsional modal frequency.

[0041] In this embodiment, by selecting a reference point on the subframe and applying a unit load excitation at the reference point, when the dynamic stiffness of the reference point is minimum, it indicates that a torsional mode has occurred at this action frequency. Since the dynamic stiffness is inconvenient to measure directly, and the dynamic stiffness is negatively correlated with the acceleration response, the IPI curve at the reference point is collected, and the response frequency corresponding to the first acceleration peak in the curve is found. The acceleration peak corresponds to the dynamic stiffness trough, and the response frequency is the modal frequency when the dynamic stiffness is minimum, that is, when the torsional mode occurs. The torsional mode can be identified by collecting the IPI curve for a short time, thereby improving the identification efficiency.

[0042] Specifically, in the existing subframe development process, when designers propose a new subframe optimization solution, that is, a subframe structure design solution, the subframe structure design data is input into a specific software, such as Hyperworks software, and all modes of the subframe, including bending modes, second-order pitch modes, opening modes, swing modes, and torsion modes, are used to output subframe modal results containing all modal-related data, and the torsion mode is found from the subframe modal results. After finding the torsion mode, the modal frequency of the torsion mode is further found. From this process, it can be seen that it takes a certain amount of time to find all the modes of the subframe through the software, and then it takes a certain amount of time to find the torsion mode and its modal frequency from the subframe modal results through manual calculation and analysis.

[0043] After adopting the technical solution of the present invention, when the designer proposes a new subframe optimization solution, that is, a subframe structure design solution, the subframe structure design data is still input into a specific software, such as Hyperworks software. However, after the subframe optimization solution is input into the software, a unit excitation load is applied to the reference point on the subframe. It is only necessary to collect the IPI curve in a short period of time, for example, collect the IPI curve for about 5 minutes, and then find out the response frequency when the first acceleration peak appears from the IPI curve. This frequency is the torsional modal frequency, which directly and significantly shortens the torsional modal analysis speed, eliminates the need to output the subframe modal results, and avoids the errors that may exist when finding the torsional mode and its modal frequency from the subframe modal results by artificial calculation and analysis in the later stage, thereby improving the data analysis accuracy.

[0044] Dynamic stiffness is used to identify the torsional mode of the subframe. The principle of dynamic stiffness is as follows:

[0045] For the frequency response analysis of low frequencies of 0-200 Hz, the modal method is used for calculation. According to the vibration system theory, for the elastic damping system, its dynamic equation is as shown in the following formula (1):

[0046]

[0047] Among them, m represents the mass of the structural member, that is, the subframe, c represents the damping coefficient of the structural member, k represents the static stiffness of the structural member, F represents the unit excitation load, and x represents the reference point displacement. represents the reference point speed, represents the acceleration of the reference point. Assuming that the system performs simple harmonic motion, the solution of the simple harmonic motion equation is x = x0e jwt Substituting into the above formula (1), the system frequency equation is shown in the following formula (2):

[0048] (-w 2 m+jwc+k)x0=F0 (2)

[0049] Among them, x0 represents the initial displacement of simple harmonic motion, w represents the excitation circular frequency, and x0 and F0 are complex constants.

[0050] Dynamic stiffness K d The calculation formula is shown in the following formula (3):

[0051]

[0052] Dynamic stiffness is a complex number related to frequency, and its amplitude is calculated as shown in the following formula (4):

[0053]

[0054] Since the measurement of acceleration signals is more convenient than that of displacement and velocity signals, it is easier to collect frequency-acceleration than dynamic stiffness-frequency compared to directly collecting dynamic stiffness. In addition, the acceleration admittance of the origin, i.e., the acceleration response, can also reflect the dynamic stiffness characteristics of the reference point. The reason is that IPI analysis is to apply a unit force to the reference point within a certain frequency range, and take this point as the response point. The curve of the acceleration of this point changing with frequency is the IPI curve. The calculation formula of IPI is shown in the following formula (5):

[0055]

[0056] Since IPI analysis only focuses on its amplitude and does not consider the phase, IPI can be expressed as the following formula (6):

[0057]

[0058] Combining formula (4) and formula (6), it can be seen that the dynamic stiffness and the acceleration response amplitude are related.

[0059] If the IPI curve has a peak at a certain frequency, that is, the acceleration is the largest, it means that the dynamic stiffness characteristics of the reference point at this frequency are poor, that is, the dynamic stiffness is the smallest. At this time, structural modes generally appear, and the IPI peak frequency is the modal frequency. According to research, for the subframe, the peak frequency of IPI that first appears in the range of 0-200Hz is the subframe torsional modal frequency. Therefore, the frequency at which the dynamic stiffness is the smallest can be directly found through the IPI curve, and this frequency is the torsional modal frequency.

[0060] like Figure 2 The IPI curve is shown in Figure 1, where the horizontal axis is the response frequency and the vertical axis is the acceleration. The first acceleration peak appears when the response frequency is 68 Hz, so 68 Hz is the subframe torsional modal frequency found based on this reference point.

[0061] Furthermore, in one embodiment, the reference point is a position point where the torsional vibration amplitude is maximum.

[0062] In this embodiment, the position point with the maximum torsional vibration amplitude can best represent the torsional mode. Selecting the position point with the maximum torsional vibration amplitude as the reference point and then collecting the IPI curve can find the first acceleration peak as quickly as possible, that is, find the torsional mode frequency as quickly as possible.

[0063] Furthermore, in one embodiment, the reference point is a corner point or a connection point on the sub-frame connected to the vehicle body.

[0064] In this embodiment, after the sub-frame is connected to the vehicle body, the torsion amplitude at the corner point or the connection point on the sub-frame connected to the vehicle body is the largest. These position points can best represent the torsion mode. Selecting the corner point or the connection point on the sub-frame connected to the vehicle body as the reference point and then collecting the IPI curve can find the first acceleration peak as quickly as possible, that is, find the torsion mode frequency as quickly as possible.

[0065] Furthermore, in one embodiment, the number of the above-mentioned reference points is at least one.

[0066] After averaging the response frequencies of all reference points, the average frequency obtained is the torsional mode frequency.

[0067] In this embodiment, in order to improve the accuracy of the torsional modal frequency finally found, multiple reference points can be selected on the subframe, multiple IPI curves can be collected, and a pending torsional modal frequency can be obtained according to each IPI curve. After averaging all the pending torsional modal frequencies, the frequency value obtained is the high-precision torsional modal frequency.

[0068] Furthermore, in one embodiment, the greater the stiffness of the sub-frame, the higher the upper limit of the action frequency range of unit load excitation.

[0069] In this embodiment, the action frequency of the general unit load excitation can meet the demand in the range of 0-200Hz. However, for the subframe of the same structure, the maximum action load excitation frequency required for the proportionally reduced subframe is greater than the maximum action load excitation frequency required for the proportionally reduced subframe. For example, the action frequency of the unit load excitation after proportional reduction is in the range of 0-300Hz. The more compact the frame structure, the higher the upper limit of the action frequency range. Selecting the upper limit of the action frequency range of the unit load excitation according to different frame structures can improve the scope of application and result accuracy of the method.

[0070] In summary, the first peak frequency output by the software is the torsional modal frequency of the subframe; the torsional modal frequency is evaluated to determine whether it meets the torsional modal target. If it does, the solution is qualified and the design is completed; if it does not, the design is optimized again.

[0071] By using the dynamic stiffness curve calculated by the subframe for rapid processing, it is possible to determine whether the target is met while outputting the torsional modal frequency, thereby accelerating the development and optimization of the subframe. For a subframe torsional mode, after calculating the 0-200Hz dynamic stiffness curve (about 5 minutes), the dynamic stiffness result file .pch is imported into the software. It only takes a few seconds to output the torsional modal frequency and target achievement status. The torsional modal result does not need to be opened in post-processing software to view the frequency, which greatly improves the simulation efficiency and accelerates the NVH performance development of the subframe.

[0072] Based on the invention, a software can be developed to quickly output the subframe torsional mode and target achievement status by inputting the dynamic stiffness curve of the subframe installation angle, which can accelerate the design optimization of the subframe mode and greatly improve the NVH development efficiency of the subframe. The present invention can be used for the development of front and rear subframes and is applicable to subframes made of different materials.

[0073] In a second aspect, an embodiment of the present application also provides a torsional mode identification device.

[0074] In one embodiment, referring to Figure 4 , Figure 4 This is a functional module diagram of an embodiment of a torsional mode identification device of the present application. Figure 4 As shown, the torsional mode identification device includes:

[0075] Action module 1, selects a reference point on the subframe and applies unit load excitation at the reference point.

[0076] The data processing module 2 collects the origin acceleration admittance IPI curve at the reference point, and extracts the response frequency corresponding to the first acceleration peak in the IPI curve as the torsional modal frequency.

[0077] In this embodiment, a reference point is selected on the subframe through the action module 1, and a unit load excitation is applied at the reference point. When the dynamic stiffness of the reference point is minimum, it indicates that a torsional mode has occurred at this action frequency. Since the dynamic stiffness is inconvenient to measure directly, and the dynamic stiffness is negatively correlated with the acceleration response, the IPI curve at the reference point is collected, and the response frequency corresponding to the first acceleration peak in the curve is found. The acceleration peak corresponds to the dynamic stiffness trough, and the response frequency is the modal frequency when the dynamic stiffness is minimum, that is, when the torsional mode occurs. The torsional mode can be identified by collecting the IPI curve for a short time, thereby improving the identification efficiency.

[0078] Specifically, in the existing subframe development process, when designers propose a new subframe optimization solution, that is, a subframe structure design solution, the subframe structure design data is input into a specific software, such as Hyperworks software, and all modes of the subframe, including bending modes, second-order pitch modes, opening modes, swing modes, and torsion modes, are used to output subframe modal results containing all modal-related data, and the torsion mode is found from the subframe modal results. After finding the torsion mode, the modal frequency of the torsion mode is further found. From this process, it can be seen that it takes a certain amount of time to find all the modes of the subframe through the software, and then it takes a certain amount of time to find the torsion mode and its modal frequency from the subframe modal results through manual calculation and analysis.

[0079] After adopting the technical solution of the present invention, when the designer proposes a new subframe optimization solution, that is, a subframe structure design solution, the subframe structure design data is still input into a specific software, such as Hyperworks software. However, after the subframe optimization solution is input into the software, a unit excitation load is applied to the reference point on the subframe. It is only necessary to collect the IPI curve in a short period of time, for example, collect the IPI curve for about 5 minutes, and then find out the response frequency when the first acceleration peak appears from the IPI curve. This frequency is the torsional modal frequency, which directly and significantly shortens the torsional modal analysis speed, eliminates the need to output the subframe modal results, and avoids the errors that may exist when finding the torsional mode and its modal frequency from the subframe modal results by artificial calculation and analysis in the later stage, thereby improving the data analysis accuracy.

[0080] Dynamic stiffness is used to identify the torsional mode of the subframe. The principle of dynamic stiffness is as follows:

[0081] For the frequency response analysis of low frequencies of 0-200 Hz, the modal method is used for calculation. According to the vibration system theory, for the elastic damping system, its dynamic equation is as shown in the following formula (1):

[0082]

[0083] Among them, m represents the mass of the structural member, that is, the subframe, c represents the damping coefficient of the structural member, k represents the static stiffness of the structural member, F represents the unit excitation load, and x represents the reference point displacement. represents the reference point speed, represents the acceleration of the reference point. Assuming that the system performs simple harmonic motion, the solution of the simple harmonic motion equation is x = x0e jwt Substituting into the above formula (1), the system frequency equation is shown in the following formula (2):

[0084] (-w 2 m+jwc+k)x0=F0 (2)

[0085] Among them, x0 represents the initial displacement of simple harmonic motion, w represents the excitation circular frequency, and x0 and F0 are complex constants.

[0086] Dynamic stiffness K d The calculation formula is shown in the following formula (3):

[0087]

[0088] Dynamic stiffness is a complex number related to frequency, and its amplitude is calculated as shown in the following formula (4):

[0089]

[0090] Since the measurement of acceleration signals is more convenient than that of displacement and velocity signals, it is easier to collect frequency-acceleration than dynamic stiffness-frequency compared to directly collecting dynamic stiffness. In addition, the acceleration admittance of the origin, i.e., the acceleration response, can also reflect the dynamic stiffness characteristics of the reference point. The reason is that IPI analysis is to apply a unit force to the reference point within a certain frequency range, and take this point as the response point. The curve of the acceleration of this point changing with frequency is the IPI curve. The calculation formula of IPI is shown in the following formula (5):

[0091]

[0092] Since IPI analysis only focuses on its amplitude and does not consider the phase, IPI can be expressed as the following formula (6):

[0093]

[0094] Combining formula (4) and formula (6), it can be seen that the dynamic stiffness and the acceleration response amplitude are related.

[0095] If the IPI curve has a peak at a certain frequency, that is, the acceleration is the largest, it means that the dynamic stiffness characteristics of the reference point at this frequency are poor, that is, the dynamic stiffness is the smallest. At this time, structural modes generally appear, and the IPI peak frequency is the modal frequency. According to research, for the subframe, the peak frequency of IPI that first appears in the range of 0-200Hz is the subframe torsional modal frequency. Therefore, the frequency at which the dynamic stiffness is the smallest can be directly found through the IPI curve, and this frequency is the torsional modal frequency.

[0096] Furthermore, in one embodiment, the reference point is a position point where the torsional vibration amplitude is maximum.

[0097] In this embodiment, the position point with the maximum torsional vibration amplitude can best represent the torsional mode. Selecting the position point with the maximum torsional vibration amplitude as the reference point and then collecting the IPI curve can find the first acceleration peak as quickly as possible, that is, find the torsional mode frequency as quickly as possible.

[0098] Furthermore, in one embodiment, the reference point is a corner point or a connection point on the sub-frame connected to the vehicle body.

[0099] In this embodiment, after the sub-frame is connected to the vehicle body, the torsion amplitude at the corner point or the connection point on the sub-frame connected to the vehicle body is the largest. These position points can best represent the torsion mode. Selecting the corner point or the connection point on the sub-frame connected to the vehicle body as the reference point and then collecting the IPI curve can find the first acceleration peak as quickly as possible, that is, find the torsion mode frequency as quickly as possible.

[0100] Furthermore, in one embodiment, the number of the above-mentioned reference points is at least one.

[0101] After averaging the response frequencies of all reference points, the average frequency obtained is the torsional mode frequency.

[0102] In this embodiment, in order to improve the accuracy of the torsional modal frequency finally found, multiple reference points can be selected on the subframe, multiple IPI curves can be collected, and a pending torsional modal frequency can be obtained according to each IPI curve. After averaging all the pending torsional modal frequencies, the frequency value obtained is the high-precision torsional modal frequency.

[0103] Furthermore, in one embodiment, the greater the stiffness of the sub-frame, the higher the upper limit of the action frequency range of unit load excitation.

[0104] In this embodiment, the action frequency of the general unit load excitation can meet the demand in the range of 0-200Hz. However, for the subframe of the same structure, the maximum action load excitation frequency required for the proportionally reduced subframe is greater than the maximum action load excitation frequency required for the proportionally reduced subframe. For example, the action frequency of the unit load excitation after proportional reduction is in the range of 0-300Hz. The more compact the frame structure, the higher the upper limit of the action frequency range. Selecting the upper limit of the action frequency range of the unit load excitation according to different frame structures can improve the scope of application and result accuracy of the method.

[0105] Further, in one embodiment, if Figure 3 As shown, the action frequency range of the above unit load excitation is 0-200Hz.

[0106] The action direction of the above unit load excitation is applied to the reference point along the Z direction of the vehicle body coordinate system.

[0107] Further, in one embodiment, if Figure 3 As shown, the action frequency range of the above unit load excitation is 0-200Hz.

[0108] The action direction of the above unit load excitation is applied to the reference point along the Z direction of the vehicle body coordinate system.

[0109] Among them, the functional implementation of each module in the above-mentioned torsional mode recognition device corresponds to the various steps in the above-mentioned torsional mode recognition method embodiment, and its functions and implementation processes are no longer repeated here.

[0110] In a third aspect, an embodiment of the present application provides a torsional mode recognition device, which may be a personal computer (PC), a laptop computer, a server, or other device with a data processing function.

[0111] Reference Figure 5 , Figure 5 Schematic diagram of the hardware structure of the torsion mode recognition device involved in the embodiment of the present application. In the embodiment of the present application, the torsion mode recognition device may include a processor, a memory, a communication interface and a communication bus.

[0112] The communication bus may be of any type and is used to interconnect the processor, the memory, and the communication interface.

[0113] The communication interface includes an input / output (I / O) interface, a physical interface, and a logical interface, etc., which are used to interconnect the devices inside the torsion mode recognition device, and an interface used to interconnect the torsion mode recognition device with other devices (such as other computing devices or user devices). The physical interface can be an Ethernet interface, an optical fiber interface, an ATM interface, etc. The user device can be a display, a keyboard, etc.

[0114] The memory can be various types of storage media, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), flash memory, optical storage, hard disk, programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), etc.

[0115] The processor may be a general-purpose processor, and the general-purpose processor may call the torsion mode recognition program stored in the memory and execute the torsion mode recognition method provided in the embodiment of the present application. For example, the general-purpose processor may be a central processing unit (CPU). The method executed when the torsion mode recognition program is called may refer to the various embodiments of the torsion mode recognition method of the present application, and will not be repeated here.

[0116] Those skilled in the art will understand that Figure 5 The hardware structure shown in the figure does not constitute a limitation on the present application, and may include more or less components than shown in the figure, or combine certain components, or arrange the components differently.

[0117] In a fourth aspect, an embodiment of the present application also provides a computer-readable storage medium.

[0118] The computer-readable storage medium of the present application stores a torsional mode recognition program, wherein when the torsional mode recognition program is executed by a processor, the steps of the torsional mode recognition method as described above are implemented.

[0119] Among them, the method implemented when the torsional mode recognition program is executed can refer to the various embodiments of the torsional mode recognition method of the present application, and will not be repeated here.

[0120] It should be noted that the serial numbers of the above-mentioned embodiments of the present application are only for description and do not represent the advantages or disadvantages of the embodiments.

[0121] The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices. The terms "first", "second" and "third" are used to distinguish different objects, etc., and do not represent a sequence, nor do they limit "first", "second" and "third" to different types.

[0122] In the description of the embodiments of the present application, "exemplary", "for example" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary", "for example" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary", "for example" or "for example" is intended to present related concepts in a specific way.

[0123] In the description of the embodiments of the present application, unless otherwise specified, “ / ” means or, for example, A / B can mean A or B; the “and / or” in the text is merely a description of the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, “multiple” refers to two or more than two.

[0124] In some processes described in the embodiments of the present application, multiple operations or steps that appear in a specific order are included, but it should be understood that these operations or steps may not be executed in the order in which they appear in the embodiments of the present application or in parallel, and the sequence number of the operation is only used to distinguish the different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed in sequence or in parallel, and these operations or steps may be combined.

[0125] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, disk, CD) as described above, and includes a number of instructions for a terminal device to execute the methods described in each embodiment of the present application.

[0126] The above are only preferred embodiments of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A torsional mode identification method, characterized in that: The torsional mode identification method comprises: Select a reference point on the subframe and apply unit load excitation at the reference point; The origin acceleration admittance IPI curve at the reference point is collected, and the response frequency corresponding to the first acceleration peak in the IPI curve is extracted as the torsional modal frequency.

2. The torsional mode identification method according to claim 1, characterized in that: The reference point is the position point with the maximum torsional vibration amplitude.

3. The torsional mode identification method according to claim 1, characterized in that: The reference point is a corner point or a connection point on the subframe connected to the vehicle body.

4. The torsional mode identification method according to claim 1, characterized in that: The number of the reference points is at least one; After averaging the response frequencies of all reference points, the average frequency obtained is the torsional mode frequency.

5. The torsional mode identification method according to claim 1, characterized in that: The greater the stiffness of the subframe, the higher the upper limit of the action frequency range of unit load excitation.

6. The torsional mode identification method according to claim 1, characterized in that: The operating frequency range of the unit load excitation is 0-200 Hz.

7. The torsional mode identification method according to claim 1, characterized in that: The unit load excitation is applied to the reference point along the Z direction of the vehicle body coordinate system.

8. A torsional mode identification system, characterized in that: The torsional mode identification system comprises: An action module, which is used to select a reference point on the subframe and apply a unit load excitation at the reference point; The data processing module is used to collect the origin acceleration admittance IPI curve at the reference point, and extract the response frequency corresponding to the first acceleration peak in the IPI curve as the torsional modal frequency.

9. A torsional mode identification device, characterized in that: The torsional mode recognition device includes a processor, a memory, and a torsional mode recognition program stored in the memory and executable by the processor, wherein when the torsional mode recognition program is executed by the processor, the steps of the torsional mode recognition method as described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a torsional mode recognition program, wherein when the torsional mode recognition program is executed by a processor, the steps of the torsional mode recognition method according to any one of claims 1 to 7 are implemented.

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