A method, system, device and medium for selecting fixed points of frame and body suspension

Abstract

The present application relates to a method, system, device and medium for selecting fixed points of a vehicle frame and a vehicle body suspension. A finite element model is established according to geometric data of a vehicle frame, front and rear brackets and a battery pack frame, and a constrained modal analysis is performed to obtain a mean degree of freedom displacement curve diagram of each sampling point in a sampling point set in the vehicle height direction; the positions of the frame and vehicle body suspension fixed points are obtained according to the mean degree of freedom displacement curve diagram and in combination with a plurality of vehicle body connection areas; during the design stage, a simulation analysis is performed on the frame nodes to obtain a mean degree of freedom displacement curve diagram, and based on the mean degree of freedom displacement curve diagram, the positions of nodes with smaller frame amplitudes are obtained, and then the vehicle body frame suspension fixed points are selected in combination with a plurality of vehicle body connection areas with greater vehicle body rigidity, and the frame vibration characteristics are fully considered, and the positions with smaller frame amplitudes and greater vehicle body rigidity are selected as the vehicle body frame suspension fixed points, so as to effectively reduce the vibration transmission from the frame to the vehicle body side and improve the NVH performance of the whole vehicle.

Description

Technical Field

[0001] The present application relates to the field of vehicle body design, and in particular to a method, system, device and medium for selecting fixed points of vehicle frame and vehicle body suspension. Background Art

[0002] At present, for non-load-bearing bodies, the body and frame are connected by suspension rubber. During the driving process of the vehicle, the vibration excitation of the body mainly comes from two aspects: the vibration excitation of the power system transmitted to the body through the frame, and the vibration excitation of the road surface transmitted to the frame through the tires and finally transmitted to the body.

[0003] Since the power system and road excitation are transmitted to the body through the frame, it will cause vibration and noise problems of the body. Reducing the vibration energy transmitted from the frame to the body can effectively reduce the vibration and noise level inside the car. Therefore, the rationality of the location of the connection point between the frame and the body has a great impact on the NVH performance of the car. How to effectively reduce the vibration transmission from the frame to the body is the focus of the layout of the frame and body suspension fixing points.

[0004] The traditional design process of the frame and body suspension fixing point is to select the position with greater body rigidity, such as the bottom of the front frame of the body, A-pillar, B-pillar, C-pillar, D-pillar and other areas as the body and frame suspension fixing point. However, the selection of the body frame suspension bracket only considers the body rigidity, and does not consider the impact of the vibration characteristics of the frame on the body, which has a certain impact on the NVH performance of the car. Summary of the invention

[0005] The embodiments of the present application provide a method, system, device and medium for selecting the fixing points of the frame and the body suspension, so as to solve the problem that the selection point position of the body frame suspension bracket in the related art only considers the rigidity of the body, but does not consider the influence of the vibration characteristics of the frame on the body, which has a certain influence on the NVH performance of the car.

[0006] In a first aspect, a method for selecting a fixed point of a frame and a body suspension is provided, which comprises:

[0007] A finite element model is established according to the geometric data of the vehicle frame, front and rear brackets, and the battery pack frame, and a sampling point set is obtained based on the finite element model;

[0008] Performing constrained modal analysis on the finite element model to obtain a mean degree of freedom displacement curve diagram of each sampling point in the vehicle height direction in the sampling point set;

[0009] According to the mean degree of freedom displacement curve diagram, and in combination with a plurality of vehicle body connection areas, the positions of the vehicle frame and vehicle body suspension fixing points are obtained.

[0010] In some embodiments, a finite element model is established according to geometric data of the vehicle frame, the front and rear brackets, and the battery pack frame, and a sampling point set is obtained based on the finite element model, specifically including the following steps:

[0011] Establish a finite element model based on the geometric data of the vehicle frame, front and rear brackets, and battery pack frame, and obtain the node coordinates of all nodes of the vehicle frame in the finite element model;

[0012] Nodal elements are generated at nodes of the frame longitudinal beams along the extending direction of the frame longitudinal beams, and then all the nodal elements are numbered and combined with the nodal coordinates to form a sampling point set.

[0013] In some embodiments, node units are generated at nodes of the frame longitudinal beams along the extension direction of the frame longitudinal beams, and then all the node units are numbered and a sampling point set is formed in combination with the node coordinates, specifically including the following steps:

[0014] Select the node of one longitudinal beam on the left and right sides of the frame along the extension direction of the longitudinal beam of the frame as the sampling point;

[0015] Generate a node unit for each sampling point, and then collect them to form a node set;

[0016] The TCL program is run to number all the node units in the node set, and to assign corresponding node coordinates to each node unit to form the sampling point set.

[0017] In some embodiments, obtaining the position of the vehicle body suspension fixing point according to the mean degree of freedom displacement curve diagram and in combination with a plurality of vehicle body connection areas includes the following steps:

[0018] Obtain the sampling point corresponding to the minimum value of the mean degree of freedom displacement in the mean degree of freedom displacement curve diagram, and use it as the initial reference point;

[0019] Obtaining corresponding points of all sampling points of the initial reference point on the vehicle body of the finite element model;

[0020] The corresponding points located in the vehicle body connection area are screened out, and the node coordinates of the sampling points corresponding to the corresponding points located in the vehicle body connection area are used as the fixed point positions of the frame and the vehicle body suspension.

[0021] In some embodiments, the plurality of vehicle body connection areas include a vehicle body front end frame bottom area, a vehicle body A-pillar, a vehicle body B-pillar area, a vehicle body C-pillar area, and a vehicle body D-pillar area.

[0022] In some embodiments, constrained modal analysis is performed on the finite element model to obtain a mean degree of freedom displacement curve of each sampling point in the vehicle height direction in the sampling point set, specifically comprising the following steps:

[0023] Performing constrained modal analysis on the finite element model to obtain a displacement value of each sampling point in the sampling point set in the vehicle height direction under all modal vibration shapes;

[0024] Based on the displacement value of each sampling point in the vehicle height direction under all modal vibration modes, and using the mean degree of freedom displacement method, the mean degree of freedom displacement value of each sampling point under all modal vibration modes is calculated respectively;

[0025] The mean degree of freedom displacement values ​​of a sampling point under all modal vibration modes are summed up to obtain the final mean degree of freedom displacement value of the sampling point;

[0026] Repeat the above steps to obtain the final mean degree of freedom displacement value of all sampling points;

[0027] The mean degree of freedom displacement curve is formed based on the final mean degree of freedom displacement value of all sampling points and the number of each sampling point.

[0028] In some embodiments, the mean degree of freedom displacement curve graph is formed based on the final mean degree of freedom displacement value of all sampling points and the number of each sampling point, including the following steps:

[0029] The mean degree of freedom displacement curve graph is formed with the final mean degree of freedom displacement value as the vertical axis and the number of each sampling point in the sampling point set as the horizontal axis.

[0030] In a second aspect, a system for selecting a fixed point of a frame and a vehicle body suspension is provided, and the system for selecting a fixed point of a frame and a vehicle body suspension comprises:

[0031] The first module is used to establish a finite element model according to the geometric data of the vehicle frame, the front and rear brackets and the battery pack frame, and obtain a sampling point set based on the finite element model;

[0032] The second module is used to perform constrained modal analysis on the finite element model to obtain a mean degree of freedom displacement curve diagram of each sampling point in the vehicle height direction in the sampling point set;

[0033] The third module is used to obtain the positions of the suspension fixing points of the frame and the body according to the mean degree of freedom displacement curve diagram and in combination with a plurality of body connection areas.

[0034] In a third aspect, a device for selecting fixed points of a frame and a vehicle body suspension is provided, the device comprising a processor, a memory, and a program for selecting fixed points of a frame and a vehicle body suspension stored in the memory and executable by the processor, wherein when the program for selecting fixed points of a frame and a vehicle body suspension is executed by the processor, the steps of a method for selecting fixed points of a frame and a vehicle body suspension are implemented.

[0035] In a fourth aspect, a computer-readable storage medium is provided, on which a program for selecting fixed points of a frame and a vehicle body suspension is stored. When the program for selecting fixed points of a frame and a vehicle body suspension is executed by a processor, the steps of a method for selecting fixed points of a frame and a vehicle body suspension are implemented.

[0036] The beneficial effects of the technical solution provided by this application include:

[0037] The embodiment of the present application provides a method, system, device and medium for selecting fixed points of a frame and a body suspension, establishes a finite element model according to geometric data of a frame, front and rear brackets and a battery pack frame, and obtains a sampling point set based on the finite element model; performs constrained modal analysis on the finite element model to obtain a mean degree of freedom displacement curve diagram of each sampling point in the sampling point set in the vehicle height direction; obtains the position of the frame and body suspension fixed points according to the mean degree of freedom displacement curve diagram and in combination with multiple body connection areas; through the above steps, the position of the frame and body suspension connection points is simulated and analyzed in the concept design stage to obtain the mean degree of freedom displacement curve diagram, and the node position with smaller frame amplitude is obtained according to the mean degree of freedom displacement curve diagram, and then, in combination with multiple body connection areas with larger body rigidity, a reasonable body frame suspension fixed point is analyzed and selected, that is, the frame vibration characteristics are fully considered, and the position with smaller frame amplitude and larger body rigidity is selected as the body frame suspension fixed point, so as to effectively reduce the vibration transmission from the frame to the body side and improve the NVH performance of the whole vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0039] Figure 1 A schematic diagram of establishing a finite element model according to geometric data of a vehicle frame, front and rear brackets, and a battery pack frame provided in an embodiment of the present application;

[0040] Figure 2 A schematic diagram of generating a node unit at a node of a frame longitudinal beam provided in an embodiment of the present application;

[0041] Figure 3 A schematic diagram of a general flow chart of a method for selecting fixed points of a frame and a body suspension provided in an embodiment of the present application;

[0042] Figure 4 This is a schematic diagram of the mean degree of freedom displacement curve provided in an embodiment of the present application. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, 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 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 making creative work are within the scope of protection of this application.

[0044] The terms that should be understood for this application are:

[0045] ADDOFD (average driving DOF displacement) refers to the average degree of freedom displacement. Its theory comes from the selection of suspension position in modal test. Modal test uses simultaneous measurement of input and output, that is, measuring excitation and response, to infer the characteristics of the system.

[0046] PLOT unit is: a common tool method for batch selection of frame nodes;

[0047] The TCL program is: a secondary development program for finite element software;

[0048] Hyperworks is a finite element pre-processing software;

[0049] The embodiments of the present application provide a method, system, device and medium for selecting the fixing points of the frame and the body suspension, so as to solve the problem that the selection point position of the body frame suspension bracket in the related art only considers the rigidity of the body, but does not consider the influence of the vibration characteristics of the frame on the body, which has a certain influence on the NVH performance of the car.

[0050] See also Figure 1-Figure 4 In a first aspect, a method for selecting a fixed point of a frame and a vehicle body suspension is provided, which comprises:

[0051] Step 100: Establish a finite element model according to the geometric data of the vehicle frame, the front and rear brackets, and the battery pack frame, and obtain a sampling point set based on the finite element model;

[0052] Step 101, performing constrained modal analysis on the finite element model to obtain a mean degree of freedom displacement curve diagram of each sampling point in a sampling point set in a vehicle height direction;

[0053] Step 102: Obtain the positions of the suspension fixing points of the vehicle frame and the vehicle body according to the mean degree of freedom displacement curve diagram and in combination with a plurality of vehicle body connection areas.

[0054] Through the above steps, the positions of the frame and body suspension connection points are simulated and analyzed in the conceptual design stage to obtain the average degree of freedom displacement curve. Based on the average degree of freedom displacement curve, the node positions with smaller amplitudes on the frame are obtained. Then, combined with multiple body connection areas with larger body rigidity, reasonable body frame suspension fixing points are selected through analysis. That is, the frame vibration characteristics are fully considered, and the positions with smaller frame amplitudes and larger body rigidity are selected as the body frame suspension fixing points, which effectively reduces the vibration transmission from the frame to the body side and improves the NVH performance of the whole vehicle.

[0055] In some preferred embodiments, in order to reduce the number of local modal vibration shapes of the battery pack and reduce the amount of calculation of modal analysis, the following settings are provided:

[0056] Step 100: Establish a finite element model according to the geometric data of the vehicle frame, the front and rear brackets, and the battery pack frame, and obtain a sampling point set based on the finite element model, specifically including:

[0057] Step 10001: Establish a finite element model based on the geometric data of the vehicle frame, front and rear brackets, and battery pack frame, and obtain the node coordinates of all nodes of the vehicle frame in the finite element model; that is, the first 5000 nodes can be reserved, and the node coordinates of the 5000 nodes can be extracted; Figure 1 Marks a, b, and c are the vehicle frame, battery pack frame, and front and rear brackets, respectively;

[0058] This step can be understood as obtaining the frame CAD geometry data, including the frame, battery pack frame, front and rear brackets, and establishing a frame finite element model. In order to reduce the number of local modal vibration shapes of the battery pack, the modules, upper and lower covers, and water cooling plates are deleted. The battery pack only retains the battery pack frame. The front and rear brackets are hard-connected to the frame and the front and rear brackets are retained.

[0059] Step 10002: Generate node units at the nodes of the frame longitudinal beams along the extension direction of the frame longitudinal beams, then number all the node units and form a sampling point set in combination with the node coordinates. Figure 2 The extension direction of the middle frame longitudinal beam is marked as d, and the generated node element is marked as e.

[0060] Step 10002 is specifically as follows:

[0061] Step 10002-1, using the PLOT unit, select nodes of one side of the longitudinal beam on the left and right sides of the frame along the extension direction of the longitudinal beam of the frame as sampling points; about 1000 sampling points;

[0062] Step 10002-2, using the PLOT unit to generate a node unit for each sampling point, and then collect them to form a node set;

[0063] Step 10002-3: Run the TCL program to number all the node units in the node set, and assign corresponding node coordinates to each node unit to form the sampling point set.

[0064] The reason for selecting only the nodes on the left longitudinal beam of the frame is that the frame and body suspension fixing points on the left longitudinal beam of the frame are symmetrical with the frame and body suspension fixing points on the right longitudinal beam of the frame. Therefore, in order to further reduce the amount of calculation and speed up the analysis steps, only the left longitudinal beam of the frame or the right longitudinal beam of the frame needs to be analyzed.

[0065] In addition, in order to facilitate the subsequent modal analysis and data processing, and to reduce the time for simulators to manually number sampling points for 95% of the nodes, significantly improve the work efficiency of simulators and avoid the problem of errors in manual sampling point numbering, the pre-processing software Hyperworks is redeveloped using the TCL program. The TCL program can realize the automatic numbering of the sampling points selected for the frame, and improve the efficiency of the analysis of the fixed point selection of the frame and body suspension.

[0066] The TCL program can reduce 95% of the time for manual node numbering by simulators, significantly improve their work efficiency and avoid errors in manual node numbering, allowing simulators to focus more on optimizing the design of structures, and has high application value.

[0067] In some preferred embodiments, step 101, performing constrained modal analysis on the finite element model to obtain a mean degree of freedom displacement curve of each sampling point in the vehicle height direction in the sampling point set, specifically includes the following steps:

[0068] Step 10100: performing constrained modal analysis on the finite element model to obtain the displacement value of each sampling point in the sampling point set in the vehicle height direction under all modal vibration modes; that is, the displacement value in the vehicle height direction under the mode in the frequency range of 1-200 Hz;

[0069] Step 10101: Based on the displacement value of each sampling point in the vehicle height direction under all modal vibration modes, the mean degree of freedom displacement value of each sampling point under all modal vibration modes is calculated using the mean degree of freedom displacement method;

[0070] Step 10102: sum up the mean degree of freedom displacement values ​​of a sampling point under all modal vibration modes to obtain the final mean degree of freedom displacement value of the sampling point;

[0071] Step 1013, repeat the above steps to obtain the final mean degree of freedom displacement value of all sampling points;

[0072] Step 1014: Based on the final average degree of freedom displacement values ​​of all sampling points and the number of each sampling point, a mean degree of freedom displacement curve graph is formed. This step specifically includes:

[0073] The final average degree of freedom displacement value is the vertical axis, and the number of each sampling point in the sampling point set is the horizontal axis to form the average degree of freedom displacement curve. The average degree of freedom displacement curve can refer to the attached Figure 4 shown.

[0074] Correspondingly, step 102, according to the mean degree of freedom displacement curve diagram, and in combination with a plurality of vehicle body connection areas, obtains the positions of the frame and vehicle body suspension fixing points, specifically including the following steps:

[0075] Step 10200, obtaining a sampling point corresponding to the minimum value of the mean degree of freedom displacement in the mean degree of freedom displacement curve diagram, and using it as an initial reference point;

[0076] Step 10201, obtaining corresponding points on the vehicle body of the finite element model corresponding to all sampling points of the initial reference point;

[0077] Step 10202: Filter out corresponding points located in the vehicle body connection area, and use the node coordinates of the sampling points corresponding to the corresponding points located in the vehicle body connection area as the positions of the frame and vehicle body suspension fixing points.

[0078] The plurality of vehicle body connection areas include a vehicle body front end frame bottom area, a vehicle body A-pillar, a vehicle body B-pillar area, a vehicle body C-pillar area, and a vehicle body D-pillar area.

[0079] In order to reduce the vibration energy transmitted from the frame to the body through the above steps, it is necessary to select a position with a smaller frame amplitude, preferably a frame node position as the suspension layout point, and use the ADDOFD algorithm to find the node where the frame transmits the least vibration energy to the body. Then, combined with the rigidity factor, the optimal suspension point is arranged at the node where the frame transmits the least vibration energy to the body and the part with high rigidity in the body connection area, thereby effectively reducing the vibration transmission from the frame to the body side and improving the NVH performance of the whole vehicle.

[0080] In a second aspect, a system for selecting a fixed point of a frame and a vehicle body suspension is provided, and the system for selecting a fixed point of a frame and a vehicle body suspension comprises:

[0081] The first module is used to establish a finite element model according to the geometric data of the vehicle frame, the front and rear brackets and the battery pack frame, and obtain a sampling point set based on the finite element model;

[0082] The second module is used to perform constrained modal analysis on the finite element model to obtain a mean degree of freedom displacement curve diagram of each sampling point in the vehicle height direction in the sampling point set;

[0083] The third module is used to obtain the positions of the suspension fixing points of the frame and the body according to the mean degree of freedom displacement curve diagram and in combination with a plurality of body connection areas.

[0084] Among them, the functional implementation of each module in the above-mentioned frame and body suspension fixed point selection system corresponds to the various steps in the above-mentioned frame and body suspension fixed point selection method embodiment, and its functions and implementation processes will not be repeated here one by one.

[0085] In a third aspect, an embodiment of the present application provides a device for selecting fixed points of a vehicle frame and a vehicle body suspension. The device for selecting fixed points of a vehicle frame and a vehicle body suspension may be a personal computer (PC), a laptop computer, a server, or other device with data processing capabilities.

[0086] In the embodiment of the present application, the device for selecting the fixed points of the frame and the body suspension may include a processor, a memory, a communication interface and a communication bus.

[0087] The communication bus may be of any type and is used to interconnect the processor, the memory, and the communication interface.

[0088] The communication interface includes input / output (I / O) interface, physical interface and logical interface, etc., which are used to realize the interconnection of the devices inside the frame and body suspension fixed point selection device, and the interface used to realize the interconnection of the frame and body suspension fixed point selection device with other devices (such as other computing devices or user devices). The physical interface can be an Ethernet interface, a fiber optic interface, an ATM interface, etc.; the user device can be a display, a keyboard, etc.

[0089] 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.

[0090] The processor may be a general-purpose processor, which may call the frame and body suspension fixed point selection program stored in the memory and execute the frame and body suspension fixed point selection 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 frame and body suspension fixed point selection program is called may refer to the various embodiments of the frame and body suspension fixed point selection method of the present application, which will not be described in detail here.

[0091] In a fourth aspect, an embodiment of the present application also provides a computer-readable storage medium.

[0092] The computer-readable storage medium of the present application stores a program for selecting fixed points of a frame and a vehicle body suspension, wherein when the program for selecting fixed points of a frame and a vehicle body suspension is executed by a processor, the steps of the method for selecting fixed points of a frame and a vehicle body suspension as described above are implemented.

[0093] Among them, the method implemented when the frame and body suspension fixed point selection program is executed can refer to the various embodiments of the frame and body suspension fixed point selection method of the present application, and will not be repeated here.

[0094] 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.

[0095] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the system or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise expressly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0096] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0097] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for selecting the fixed points of the frame and the body suspension, characterized in that: It includes: A finite element model is established according to the geometric data of the vehicle frame, front and rear brackets, and the battery pack frame, and a sampling point set is obtained based on the finite element model; A finite element model is established according to the geometric data of the frame, the front and rear brackets and the battery pack frame, and a sampling point set is obtained based on the finite element model, which specifically includes the following steps: a finite element model is established according to the geometric data of the frame, the front and rear brackets and the battery pack frame, and the node coordinates of all nodes of the frame in the finite element model are obtained; along the extension direction of the frame longitudinal beam, node units are generated at the nodes of the frame longitudinal beam, and then all node units are numbered, and a sampling point set is formed in combination with the node coordinates; along the extension direction of the frame longitudinal beam, node units are generated at the nodes of the frame longitudinal beam, and then all node units are numbered, and a sampling point set is formed in combination with the node coordinates, which specifically includes the following steps: a node of one side of the longitudinal beam on the left and right sides of the frame in the extension direction of the frame longitudinal beam is selected as a sampling point; a node unit is generated for each sampling point, and then collected to form a node set; a TCL program is run to number all node units in the node set, and corresponding node coordinates are assigned to each node unit to form the sampling point set; The finite element model is subjected to constrained modal analysis to obtain a mean degree of freedom displacement curve diagram of each sampling point in the sampling point set in the vehicle height direction; the finite element model is subjected to constrained modal analysis to obtain a mean degree of freedom displacement curve diagram of each sampling point in the sampling point set in the vehicle height direction, specifically comprising the following steps: the finite element model is subjected to constrained modal analysis to obtain a displacement value of each sampling point in the sampling point set in the vehicle height direction under all modal vibration modes; based on the displacement value of each sampling point in the vehicle height direction under all modal vibration modes, and using the mean degree of freedom displacement method, the mean degree of freedom displacement value of each sampling point under all modal vibration modes is calculated respectively; the mean degree of freedom displacement values ​​of a sampling point under all modal vibration modes are summed and accumulated to obtain a final mean degree of freedom displacement value of the sampling point; the above steps are repeated to obtain a final mean degree of freedom displacement value of all sampling points; the mean degree of freedom displacement curve diagram is formed based on the final mean degree of freedom displacement value of all sampling points and the serial number of each sampling point; According to the average degree of freedom displacement curve diagram, and in combination with multiple body connection areas, the position of the frame and body suspension fixing point is obtained; according to the average degree of freedom displacement curve diagram, and in combination with multiple body connection areas, the position of the body suspension fixing point is obtained, including the following steps: obtaining the sampling point corresponding to the minimum value of the average degree of freedom displacement in the average degree of freedom displacement curve diagram, and using it as the initial reference point; obtaining the corresponding points on the body of the finite element model corresponding to all the sampling points of the initial reference point; screening out the corresponding points located in the body connection area, and using the node coordinates of the sampling points corresponding to the corresponding points located in the body connection area as the position of the frame and body suspension fixing point.

2. The method for selecting the fixing points of the frame and the vehicle body suspension according to claim 1, characterized in that: The plurality of vehicle body connection areas include a vehicle body front end frame bottom area, a vehicle body A-pillar, a vehicle body B-pillar area, a vehicle body C-pillar area, and a vehicle body D-pillar area.

3. The method for selecting the fixing points of the frame and the vehicle body suspension according to claim 1, characterized in that: The mean degree of freedom displacement curve diagram is formed based on the final mean degree of freedom displacement values ​​of all sampling points and the serial number of each sampling point, including the following steps: The mean degree of freedom displacement curve graph is formed with the final mean degree of freedom displacement value as the vertical axis and the number of each sampling point in the sampling point set as the horizontal axis.

4. A system for selecting fixed points of frame and vehicle body suspension, characterized in that: The frame and body suspension fixing point selection system comprises: The first module is used to establish a finite element model according to the geometric data of the frame, front and rear brackets and battery pack frame, and obtain a sampling point set based on the finite element model; establish a finite element model according to the geometric data of the frame, front and rear brackets and battery pack frame, and obtain a sampling point set based on the finite element model, specifically including the following steps: establish a finite element model according to the geometric data of the frame, front and rear brackets and battery pack frame, and obtain the node coordinates of all nodes of the frame in the finite element model; generate node units at the nodes of the frame longitudinal beam along the extension direction of the frame longitudinal beam, and then number all the node units, and combine The node coordinates form a sampling point set; along the extension direction of the frame longitudinal beam, node units are generated at the nodes of the frame longitudinal beam, and then all the node units are numbered, and the sampling point set is formed in combination with the node coordinates, which specifically includes the following steps: selecting the nodes of one longitudinal beam on the left and right sides of the frame along the extension direction of the frame longitudinal beam as sampling points; generating a node unit for each sampling point, and then collecting to form a node set; running a TCL program to number all the node units in the node set, and assigning corresponding node coordinates to each node unit to form the sampling point set; The second module is used to perform constrained modal analysis on the finite element model to obtain a mean degree of freedom displacement curve diagram of each sampling point in the sampling point set in the vehicle height direction; the finite element model is subjected to constrained modal analysis to obtain a mean degree of freedom displacement curve diagram of each sampling point in the sampling point set in the vehicle height direction, specifically comprising the following steps: performing constrained modal analysis on the finite element model to obtain a displacement value of each sampling point in the sampling point set in the vehicle height direction under all modal vibration modes; based on the displacement value of each sampling point in the vehicle height direction under all modal vibration modes, and using the mean degree of freedom displacement method, respectively calculate the mean degree of freedom displacement value of each sampling point under all modal vibration modes; summing up the mean degree of freedom displacement values ​​of a sampling point under all modal vibration modes to obtain a final mean degree of freedom displacement value of the sampling point; repeating the above steps to obtain a final mean degree of freedom displacement value of all sampling points; forming a mean degree of freedom displacement curve diagram based on the final mean degree of freedom displacement value of all sampling points and the number of each sampling point; The third module is used to obtain the position of the fixed point of the frame and the body suspension according to the average degree of freedom displacement curve diagram and in combination with multiple body connection areas; according to the average degree of freedom displacement curve diagram and in combination with multiple body connection areas, the position of the body suspension fixed point is obtained, including the following steps: obtaining the sampling point corresponding to the minimum value of the average degree of freedom displacement in the average degree of freedom displacement curve diagram, and using it as the initial reference point; obtaining the corresponding points of all sampling points of the initial reference point on the body of the finite element model; screening out the corresponding points located in the body connection area, and using the node coordinates of the sampling points corresponding to the corresponding points located in the body connection area as the position of the fixed point of the frame and the body suspension.

5. A device for selecting fixed points of frame and body suspension, characterized in that: The frame and body suspension fixed point selection device includes a processor, a memory, and a frame and body suspension fixed point selection program stored in the memory and executable by the processor, wherein when the frame and body suspension fixed point selection program is executed by the processor, the steps of the frame and body suspension fixed point selection method as described in any one of claims 1 to 3 are implemented.

6. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a program for selecting fixed points of a frame and a vehicle body suspension, wherein when the program for selecting fixed points of a frame and a vehicle body suspension is executed by a processor, the steps of the method for selecting fixed points of a frame and a vehicle body suspension as described in any one of claims 1 to 3 are implemented.

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