Method and system for setting dynamic stiffness target of suspension passive side bracket in pure electric vehicle

Abstract

The application belongs to the technical field of vehicle vibration and noise control, and discloses a suspension passive side support dynamic stiffness target setting method and system for a pure electric vehicle, which comprises the following steps: first, determining the relevant parameters of the target suspension, including position coordinates, power assembly mass center position, mass, etc.; then, obtaining the static stiffness matrix of the target suspension through calculation; subsequently, analyzing the displacement of the power assembly at the maximum torque and the stress condition of the target suspension; then, obtaining the static stiffness curve of the target suspension, and combining the dynamic-static ratio curve to obtain the dynamic stiffness curve; finally, setting the dynamic stiffness target of the passive side support of the target suspension according to the dynamic stiffness curve, the isolation efficiency coefficient and the project layout type. The method can fully consider the influence of the motor torque, the suspension stiffness and the layout architecture and the like, and obtain a reasonable dynamic stiffness target of the passive end support of the suspension to effectively control the howling level of the pure electric sample vehicle.

Description

Technical Field

[0001] This invention belongs to the field of vehicle vibration and noise control technology, specifically relating to a method and system for setting the dynamic stiffness target of the passive side support of a pure electric vehicle. Background Technology

[0002] With social development and the government's vigorous promotion of new energy vehicles, the full electrification of automobiles is an inevitable trend, and many domestic and foreign OEMs have joined the research and development of pure electric vehicles. However, the excitation sources of pure electric vehicles are very different from those of traditional fuel vehicles. Traditional fuel vehicles are mainly driven by low frequencies, while pure electric vehicles are mainly driven by high frequencies, which can easily produce various harsh whistling noises, reducing the user experience of pure electric vehicles. Therefore, how to control the whistling level of pure electric vehicles has become a key research focus for various automakers.

[0003] During the digital prototype stage, the target for the whistling sound of pure electric vehicles is decomposed. The dynamic stiffness of the passive side support of the suspension is one of the key factors in controlling the whistling sound of the whole vehicle. Therefore, how to reasonably set the target for the dynamic stiffness of the passive side support of the suspension becomes a critical issue. If the dynamic stiffness is too low, it may cause the vehicle body to vibrate significantly, thus triggering the whistling sound; while if the dynamic stiffness is too high, the suspension system may not be able to effectively absorb the impact, resulting in a decrease in ride comfort.

[0004] Currently, many OEMs primarily use data from base vehicles and competitor vehicles to set a target value for the dynamic stiffness of the passive side suspension bracket. Furthermore, some projects lack corresponding base vehicles and competitor vehicles, so they provide an empirical value as a target. This approach to setting targets fails to consider factors specific to the project, resulting in a lack of rationality. Existing targets for the dynamic stiffness of the passive side suspension bracket in pure electric vehicles do not take into account the influence of factors such as motor torque, suspension stiffness, and layout architecture, making it difficult to obtain a reasonable target for the dynamic stiffness of the passive side suspension bracket to effectively control the squealing level of pure electric prototype vehicles. Summary of the Invention

[0005] Based on this, this application proposes a method and system for setting the dynamic stiffness target of the passive side bracket of the suspension for pure electric vehicles. The aim is to fully consider the influence of factors such as motor torque, suspension stiffness and layout structure to obtain a reasonable dynamic stiffness target of the passive side bracket of the suspension in order to effectively control the whistling level of the pure electric prototype vehicle.

[0006] The first aspect of this application provides a method for setting a target dynamic stiffness of the suspension passive side bracket of a pure electric vehicle, the method comprising:

[0007] Determine the position coordinates of the target mount, the position coordinates of the powertrain center of gravity, the mass of the powertrain, the maximum torque of the motor, the speed ratio of the reducer, and the static stiffness of the linear segment of the target mount in each direction;

[0008] The static stiffness matrix of the target suspension is obtained based on the position coordinates of the target suspension, the position coordinates of the center of mass of the powertrain, and the static stiffness of the linear segment.

[0009] Based on the static stiffness matrix, the powertrain mass, the maximum torque of the motor, and the speed ratio of the reducer, the powertrain displacement when subjected to the maximum torque is obtained, and the forces on the target suspension in each direction are obtained based on the powertrain displacement.

[0010] Obtain the static stiffness curves of the target suspension in each direction to determine the slope at the point where the suspension is subjected to force; the slope is the static stiffness at the point where the suspension is subjected to force.

[0011] The dynamic-to-static ratio of the target suspension in each direction at a preset frequency is obtained, and the dynamic-to-static ratio curve is obtained through empirical formulas. The dynamic stiffness curve is obtained based on the dynamic-to-static ratio curve and the static stiffness at the stress point of the suspension.

[0012] The target dynamic stiffness of the passive side support for the suspension is obtained based on the dynamic stiffness curve, the desired isolation efficiency coefficient, and the project layout architecture type.

[0013] Compared with existing technologies, this application provides a method for setting the dynamic stiffness target of the passive side bracket of a pure electric vehicle suspension. This method constructs a static stiffness matrix by determining the position coordinates of the target suspension, the position coordinates of the powertrain center of mass, and the static stiffness of the linear segments of the target suspension in each direction. This matrix describes the stiffness characteristics of the target suspension in each direction. The construction of the static stiffness matrix helps to understand the mechanical behavior of the suspension under static conditions, providing a foundation for subsequent dynamic analysis. Using the static stiffness matrix, powertrain mass, maximum motor torque, and reducer ratio, the powertrain displacement under maximum torque can be calculated. Through the powertrain displacement, the stress situation of the target suspension in each direction can be further obtained, which helps to evaluate the stress state of the suspension when bearing the weight and torque of the powertrain. Through experiments or theoretical analysis, the static stiffness curves of the target suspension in each direction are obtained. These curves describe the static stiffness changes of the suspension under different displacements. At a preset frequency, the target suspension... The dynamic-to-static ratio (DVR) is set in each direction. The DVR is the ratio of the dynamic stiffness to the static stiffness of the suspension, reflecting its stiffness characteristics under dynamic conditions. An empirical formula can be used to plot the DVR curve, which describes the change in the DVR at different frequencies. Using the DVR curve and the static stiffness at the stress point of the suspension, the dynamic stiffness curve can be calculated. The dynamic stiffness curve describes the stiffness characteristics of the suspension under dynamic conditions and is crucial for evaluating its dynamic performance. Based on the dynamic stiffness curve, the desired isolation efficiency coefficient, and the project layout type, the target dynamic stiffness of the passive side bracket of the suspension can be determined. The desired isolation efficiency coefficient reflects the suspension's effectiveness in vibration isolation, while the project layout type affects the suspension's dynamic response. Therefore, this method fully considers the influence of factors such as motor torque, suspension stiffness, and layout, obtaining a reasonable target dynamic stiffness for the passive side bracket of the suspension to effectively control the howling level of the pure electric prototype. Furthermore, effectively setting the target dynamic stiffness of the passive side bracket of the suspension for pure electric vehicles optimizes the dynamic performance of the suspension and improves the overall vehicle comfort and stability.

[0014] As an optional implementation of the first aspect, the formula for calculating the static stiffness matrix is:

[0015] ,

[0016] Where K represents the static stiffness matrix, n represents the number of suspension mounts, and T represents the matrix transpose. , ( x o , y o , z o ) represents the coordinates of the powertrain's center of mass. x i , y i, z i ) represents the position coordinates of the i-th suspension. , k x Let X represent the static stiffness of the linear segment in the X direction of the i-th suspension. k y Let represent the static stiffness of the linear segment in the Y direction of the i-th suspension. k z This represents the static stiffness of the Z-direction linear segment of the i-th suspension.

[0017] As an optional implementation of the first aspect, the formula for calculating the powertrain displacement when the powertrain is subjected to maximum torque is as follows:

[0018] ,

[0019] in, Q Indicates powertrain displacement. m represents the powertrain mass. This indicates the maximum torque of the motor, and W indicates the speed ratio of the reducer.

[0020] As an optional implementation of the first aspect, the formula for calculating the forces acting on the target suspension in each direction is:

[0021] ,

[0022] in, This represents the forces acting on the i-th suspension in each direction.

[0023] As an optional implementation of the first aspect, the formula for calculating the slope at the point where the suspension is subjected to force is:

[0024] ,

[0025] in,( , )and( , ) represent the two adjacent coordinate points of the suspension force F at the corresponding point on the static stiffness curve.

[0026] As an optional implementation of the first aspect, the empirical formula is:

[0027] ,

[0028] in, The curve represents the dynamic-to-static ratio, where B represents the dynamic-to-static ratio and f represents the preset frequency.

[0029] The formula for calculating the dynamic stiffness curve is:

[0030] ,

[0031] in, This represents the dynamic stiffness curve.

[0032] As an optional implementation of the first aspect, the step of obtaining the target dynamic stiffness of the target suspended passive side support based on the dynamic stiffness curve, the desired isolation efficiency coefficient, and the project layout architecture type includes:

[0033] Multiplying the dynamic stiffness curve by the desired isolation efficiency coefficient yields the initial target suspension passive side support dynamic stiffness curve. ;

[0034] Based on the project layout architecture type and the above... The target dynamic stiffness of the passive side support of the target suspension is obtained:

[0035] If the project's structural type is a monocoque chassis, and there is no vibration isolation at the connection between the subframe where the powertrain is mounted and the body, then the target dynamic stiffness of the target passive side mount is: ;

[0036] If the project's structural type is a monocoque chassis, and vibration isolation exists at the connection between the subframe where the powertrain is mounted and the body, then the target dynamic stiffness of the passive side support for the target suspension is: ;

[0037] If the project's structural type is a non-load-bearing body, then the target dynamic stiffness of the target passive side support is: .

[0038] A second aspect of this application provides a system for setting the dynamic stiffness target of the suspension passive side bracket of a pure electric vehicle, the system comprising:

[0039] The suspension data acquisition module is used to determine the position coordinates of the target suspension, the position coordinates of the powertrain center of gravity, the mass of the powertrain, the maximum torque of the motor, the speed ratio of the reducer, and the static stiffness of the linear segment of the target suspension in each direction.

[0040] The data matrixing module is used to obtain the static stiffness matrix of the target suspension based on the position coordinates of the target suspension, the position coordinates of the center of mass of the powertrain, and the static stiffness of the linear segment.

[0041] The suspension force determination module is used to obtain the powertrain displacement when the powertrain is subjected to the maximum torque based on the static stiffness matrix, the powertrain mass, the maximum torque of the motor and the speed ratio of the reducer, and to obtain the force on the target suspension in each direction based on the powertrain displacement;

[0042] The static stiffness determination module is used to obtain the static stiffness curves of the target suspension in each direction to determine the slope at the point where the suspension is subjected to force, and the slope is the static stiffness at the point where the suspension is subjected to force.

[0043] The suspension dynamic stiffness determination module is used to obtain the dynamic-to-static ratio of the target suspension in each direction at a preset frequency, obtain the dynamic-to-static ratio curve through empirical formulas, and obtain the dynamic stiffness curve based on the dynamic-to-static ratio curve and the static stiffness at the stress point of the suspension.

[0044] The support dynamic stiffness determination module is used to obtain the target dynamic stiffness of the target suspended passive side support based on the dynamic stiffness curve, the desired isolation efficiency coefficient and the project layout architecture type.

[0045] A third aspect of this application provides a computer device, the computer device including a memory, a processor, and a processing program stored in the memory and executable on the processor, wherein when the processing program is executed by the processor, it implements the above-described method for setting the dynamic stiffness target of the suspension passive side support of a pure electric vehicle.

[0046] A fourth aspect of this application provides a storage medium storing a processing program, which, when executed by a processor, performs the above-described method for setting the dynamic stiffness target of the suspension passive side support of a pure electric vehicle.

[0047] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by means of embodiments thereof. Attached Figure Description

[0048] Figure 1 A flowchart of a method for setting the dynamic stiffness target of the suspension passive side bracket of a pure electric vehicle according to the first embodiment of this application;

[0049] Figure 2 This is a schematic diagram of the powertrain layout of the pure electric vehicle project in the second embodiment of this application;

[0050] Figure 3 This is the static stiffness curve of the right suspension in the Z direction for a pure electric vehicle model project in the second embodiment of this application;

[0051] Figure 4 This is the dynamic-to-static ratio curve of the right suspension Z-axis of a pure electric vehicle project in the second embodiment of this application;

[0052] Figure 5 This is the target curve for the Z-direction dynamic stiffness of the right suspension passive side bracket of a pure electric vehicle project in the second embodiment of this application;

[0053] Figure 6The noise level of the driver's side motor in a pure electric vehicle in the second embodiment of this application is the 24th order.

[0054] Figure 7 The Z-axis dynamic stiffness of the right suspension passive side bracket of a pure electric vehicle project in the second embodiment of this application;

[0055] Figure 8 This document presents a comparison of the Z-axis dynamic stiffness of the right suspension passive side bracket of a pure electric vehicle project before and after optimization, as shown in the second embodiment of this application.

[0056] Figure 9 This document presents a comparison of the 24th-order noise of the in-vehicle motor of a pure electric vehicle project before and after optimization, as shown in the second embodiment of this application.

[0057] Figure 10 This is a structural schematic diagram of a dynamic stiffness target setting system for a suspension passive side bracket of a pure electric vehicle, as proposed in the third embodiment of this application.

[0058] The following detailed description, in conjunction with the accompanying drawings, will further illustrate this application. Detailed Implementation

[0059] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0060] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0061] To illustrate the technical solution described in this application, specific embodiments are provided below.

[0062] Example 1

[0063] Please see Figure 1 This is a flowchart of a method for setting the dynamic stiffness target of the suspension passive side bracket of a pure electric vehicle according to the first embodiment of this application. The proposed method includes:

[0064] S01: Determine the position coordinates of the target suspension, the position coordinates of the powertrain center of mass, the mass of the powertrain, the maximum torque of the motor, the speed ratio of the reducer, and the static stiffness of the linear segments of the target suspension in each direction.

[0065] S02: Based on the position coordinates of the target suspension, the position coordinates of the powertrain center of mass, and the static stiffness of the linear segment, obtain the static stiffness matrix of the target suspension;

[0066] It should be noted that the static stiffness matrix provides designers with information on the stiffness distribution of the suspension system, which helps to optimize the design phase and improve the performance and stability of the suspension system. The static stiffness matrix is ​​also the basis for dynamic response analysis, which can help predict the response characteristics of the system under external excitation, thereby improving the comfort and safety of the whole vehicle. By monitoring and analyzing the static stiffness matrix, abnormal changes in the suspension system can be detected in a timely manner, assisting in fault diagnosis and maintenance decisions.

[0067] Specifically, the formula for calculating the static stiffness matrix of the target suspension is:

[0068] (1)

[0069] Where K represents the static stiffness matrix, n represents the number of suspension mounts, and T represents the matrix transpose. , ( x o , y o , z o ) represents the coordinates of the powertrain's center of mass. x i , y i , z i ) represents the position coordinates of the i-th suspension. , k x Let X represent the static stiffness of the linear segment in the X direction of the i-th suspension. k y Let represent the static stiffness of the linear segment in the Y direction of the i-th suspension. k z This represents the static stiffness of the Z-direction linear segment of the i-th suspension.

[0070] S03: Based on the static stiffness matrix, the powertrain mass, the maximum torque of the motor, and the speed ratio of the reducer, the powertrain displacement when subjected to the maximum torque is obtained, and the forces on the target suspension in each direction are obtained based on the powertrain displacement.

[0071] Specifically, the formula for calculating the powertrain displacement when the powertrain is subjected to maximum torque is as follows:

[0072] (2)

[0073] in, Q Indicates powertrain displacement. m represents the powertrain mass. This indicates the maximum torque of the motor, and W indicates the speed ratio of the reducer.

[0074] Furthermore, the formulas for calculating the forces acting on the target suspension in each direction are as follows:

[0075] (3)

[0076] in, This represents the forces acting on the i-th suspension in each direction.

[0077] In this step, the displacement of the powertrain under maximum torque is calculated to further obtain the forces acting on the target mount in each direction. This result is crucial for the design and optimization of the mount system, as it helps engineers determine the required support force and stiffness to ensure the stability and reliability of the powertrain under various operating conditions. Furthermore, analyzing the forces acting on the target mount in each direction allows for the evaluation of the mount system's vibration reduction effect, providing a basis for further improvements to the mount system.

[0078] S04: Obtain the static stiffness curves of the target suspension in each direction to determine the slope at the point where the suspension is subjected to force, and the slope is the static stiffness at the point where the suspension is subjected to force.

[0079] Static stiffness is a crucial indicator of a suspension system's performance, reflecting its ability to resist deformation under stress. By obtaining static stiffness curves in different directions, the stiffness characteristics of the suspension in each direction can be understood, providing guidance for designing suitable suspension structures and parameters. These static stiffness curves are typically provided by the suspension supplier. Furthermore, determining the slope helps engineers assess the stress conditions of the suspension system, providing a basis for material selection and installation location.

[0080] Specifically, the formula for calculating the slope at the point of suspension under stress is:

[0081] (4)

[0082] in,( , )and( , ) represent the two adjacent coordinate points of the suspension force F at the corresponding point on the static stiffness curve.

[0083] S05: Obtain the dynamic-to-static ratio of the target suspension in each direction at a preset frequency, obtain the dynamic-to-static ratio curve through empirical formulas, and obtain the dynamic stiffness curve based on the dynamic-to-static ratio curve and the static stiffness at the stress point of the suspension.

[0084] Understandably, the dynamic-to-static ratio is a crucial parameter describing the stress state of a suspension under both dynamic and static conditions. By obtaining dynamic-to-static ratio curves in different directions, a comprehensive understanding of the suspension's dynamic performance can be achieved, and this ratio is typically provided by the suspension supplier. The application of empirical formulas allows for fitting and correction based on actual conditions, improving the accuracy and reliability of the dynamic-to-static ratio curve. The dynamic stiffness curve further reflects the stiffness characteristics of the suspension under dynamic loads, which is significant for evaluating the suspension's vibration reduction effect and structural stability. By combining the dynamic-to-static ratio curve and static stiffness, the dynamic response of the suspension in actual operation can be predicted more accurately, providing strong support for suspension design and optimization.

[0085] Specifically, the empirical formula is:

[0086] (5)

[0087] in, The curve represents the dynamic-to-static ratio, where B represents the dynamic-to-static ratio and f represents the preset frequency.

[0088] Furthermore, the formula for calculating the dynamic stiffness curve is:

[0089] (6)

[0090] in, This represents the dynamic stiffness curve.

[0091] S06: The target dynamic stiffness of the target suspension passive side support is obtained based on the dynamic stiffness curve, the desired isolation efficiency coefficient, and the project layout architecture type.

[0092] Understandably, the dynamic stiffness curve provides a direct understanding of the dynamic characteristics of the suspension system at different frequencies, offering a reference for design. The desired isolation efficiency coefficient reflects the isolation effect of the suspension system within a specific frequency range, helping to optimize suspension parameters and improve the overall vehicle comfort and handling. In this method, considering that the dynamic stiffness between the passive side supports of the target suspension should achieve effective vibration isolation and noise reduction, the target suspension dynamic stiffness is usually multiplied by the desired isolation efficiency coefficient. Based on experience, a value of 3 is generally considered reasonable for this desired isolation efficiency coefficient. The project layout architecture type determines the layout and connection method of the suspension system, significantly impacting the determination of the dynamic stiffness target. By comprehensively considering these factors, the dynamic stiffness target of the passive side support of the target suspension can be determined more accurately, providing a basis for subsequent design and optimization.

[0093] Specifically, the dynamic stiffness curve is multiplied by the desired isolation efficiency coefficient to obtain the initial target suspension passive side support dynamic stiffness curve. ;

[0094] Based on the project layout architecture type and the above... The target dynamic stiffness of the passive side support of the target suspension is obtained:

[0095] If the project's structural type is a monocoque chassis (chassis directly mounted to the body, without a frame), and there is no vibration isolation at the connection between the subframe housing the powertrain and the body, then the target dynamic stiffness of the target passive side mount is: ;

[0096] If the project's structural type is a monocoque chassis (chassis directly mounted to the body, without a frame), and vibration isolation exists at the connection between the subframe housing the powertrain and the body, then the target dynamic stiffness of the passive side support for the target suspension is: ;

[0097] If the project's layout architecture type is a non-load-bearing body (with a frame), then the target dynamic stiffness of the target suspension passive side bracket is: .

[0098] In summary, this method constructs a static stiffness matrix by determining the position coordinates of the target suspension, the position coordinates of the powertrain's center of mass, and the static stiffness of the linear segments of the target suspension in each direction. This matrix describes the stiffness characteristics of the target suspension in each direction. The construction of the static stiffness matrix helps to understand the mechanical behavior of the suspension under static conditions, providing a foundation for subsequent dynamic analysis. Using the static stiffness matrix, powertrain mass, maximum motor torque, and reducer ratio, the powertrain displacement under maximum torque can be calculated. Through the powertrain displacement, the stress state of the target suspension in each direction can be further obtained, which helps to evaluate the stress state of the suspension under the weight and torque of the powertrain. Through experiments or theoretical analysis, the static stiffness curves of the target suspension in each direction are obtained. These curves describe the static stiffness changes of the suspension under different displacements. At a preset frequency, the static stiffness of the target suspension is obtained through experiments or theoretical calculations. The dynamic-to-static ratio (DVR) is set in each direction. The DVR is the ratio of the dynamic stiffness to the static stiffness of the suspension, reflecting its stiffness characteristics under dynamic conditions. An empirical formula can be used to plot the DVR curve, which describes the change in the DVR at different frequencies. Using the DVR curve and the static stiffness at the stress point of the suspension, the dynamic stiffness curve can be calculated. The dynamic stiffness curve describes the stiffness characteristics of the suspension under dynamic conditions and is crucial for evaluating its dynamic performance. Based on the dynamic stiffness curve, the desired isolation efficiency coefficient, and the project layout type, the target dynamic stiffness of the passive side bracket of the suspension can be determined. The desired isolation efficiency coefficient reflects the suspension's effectiveness in vibration isolation, while the project layout type affects the suspension's dynamic response. Therefore, this method fully considers the influence of factors such as motor torque, suspension stiffness, and layout, obtaining a reasonable target dynamic stiffness for the passive side bracket of the suspension to effectively control the howling level of the pure electric prototype. Furthermore, effectively setting the target dynamic stiffness of the passive side bracket of the suspension for pure electric vehicles optimizes the dynamic performance of the suspension and improves the overall vehicle comfort and stability.

[0099] Example 2

[0100] The second embodiment of this application proposes the following steps for setting the dynamic stiffness target of the suspension passive side bracket of a pure electric vehicle:

[0101] S001: The powertrain layout of a certain pure electric vehicle is as follows Figure 2 As shown, the powertrain mass, powertrain center of mass coordinates, motor maximum torque, reducer speed ratio, suspension position coordinates and linear segment static stiffness data of a certain pure electric vehicle project are collected in Table 1. The suspension forces of the three suspensions in three directions when the powertrain is subjected to the maximum torque are calculated by formulas (1), (2) and (3) and are shown in Table 2. The suspension force of the right suspension in the Z direction is 4977N.

[0102] Table 1. Collection of parameters required for calculating suspension stress in a pure electric vehicle project.

[0103]

[0104] Table 2. Suspension Forces under Maximum Torque in a Pure Electric Vehicle Project

[0105]

[0106] S002: Figure 3 The static stiffness curve of the right suspension in the Z direction is given. According to formula (4), the slope of the static stiffness curve at the suspension force of 4977N is 1593N / mm, that is, the static stiffness of the right suspension in the Z direction is 1593N / mm when it is subjected to a force of 4977N.

[0107] S003: The dynamic-to-static ratio of the right suspension in the Z direction at 2Hz is 1.5. According to the empirical formula (5), the dynamic-to-static ratio curve from 100Hz to 1200Hz is as follows. Figure 4 As shown.

[0108] S004: According to formula (6), multiplying 1593 N / mm by the dynamic-to-static ratio curve yields the suspension dynamic stiffness curve, and then multiplying by the desired isolation efficiency coefficient 3 yields the P(f) curve. Furthermore, this pure electric project has a load-bearing body and no vibration isolation at the connection between the subframe of the powertrain and the body. Therefore, the P(f) curve is the target curve for the dynamic stiffness of the passive side support of the suspension. Figure 5 As shown.

[0109] Case studies

[0110] Taking the aforementioned pure electric project as an example, the rationality of the method of the present invention will be explained and demonstrated.

[0111] During full-throttle acceleration in a certain pure electric vehicle project, a noticeable whine was observed in the driver's seat area, which was unacceptable. Test data revealed that the whine was primarily contributed by the 24th-order motor. Figure 6 As shown, the problem frequency is around 850Hz, reaching 45dBA, while the target is 40dBA, which does not meet the target.

[0112] After investigation, it was determined that the main cause of the problem was the low Z-axis dynamic stiffness of the right suspension passive side bracket. Figure 7 As shown, the dynamic stiffness of the right suspension passive side bracket is approximately 5300 N / mm at around 850 Hz, which meets the target of 5000 N / mm established through experience during the digital prototype stage of this project. However, it does not meet the dynamic stiffness curve of the suspension passive side bracket established by the method of this invention. Figure 5 curve);

[0113] The Z-axis dynamic stiffness of the right-mounted passive side support was analyzed and optimized using CAE. The Z-axis dynamic stiffness of the right-mounted passive side support now meets the dynamic stiffness target set by the method of this invention. Figure 8As shown, and verified in a real vehicle, the noise level of the driver's motor under full-throttle acceleration conditions has been significantly optimized to the 24th order. Figure 9 As shown, the noise level inside the vehicle meets the target and is subjectively acceptable, thus demonstrating that the dynamic stiffness target of the passive side support of the suspension, formulated by the method of the present invention, is reasonable.

[0114] Example 3

[0115] Please see Figure 10 The diagram shown is a structural schematic of a dynamic stiffness target setting system for the passive side support of a pure electric vehicle according to the third embodiment of this application. The system includes:

[0116] The suspension data acquisition module 10 is used to determine the position coordinates of the target suspension, the position coordinates of the powertrain center of gravity, the mass of the powertrain, the maximum torque of the motor, the speed ratio of the reducer, and the static stiffness of the linear segment of the target suspension in each direction.

[0117] The data matrixing module 20 is used to obtain the static stiffness matrix of the target suspension based on the position coordinates of the target suspension, the position coordinates of the center of mass of the powertrain, and the static stiffness of the linear segment.

[0118] The suspension force determination module 30 is used to obtain the powertrain displacement when the powertrain is subjected to the maximum torque based on the static stiffness matrix, the powertrain mass, the maximum torque of the motor and the speed ratio of the reducer, and to obtain the force on the target suspension in each direction based on the powertrain displacement;

[0119] The suspension static stiffness determination module 40 is used to obtain the static stiffness curves of the target suspension in each direction, so as to determine the slope at the point where the suspension is subjected to force, and the slope is the static stiffness at the point where the suspension is subjected to force.

[0120] The suspension dynamic stiffness determination module 50 is used to obtain the dynamic-to-static ratio of the target suspension in each direction at a preset frequency, obtain the dynamic-to-static ratio curve through an empirical formula, and obtain the dynamic stiffness curve based on the dynamic-to-static ratio curve and the static stiffness at the stress point of the suspension.

[0121] The support dynamic stiffness determination module 60 is used to obtain the target dynamic stiffness of the target suspended passive side support based on the dynamic stiffness curve, the expected isolation efficiency coefficient and the project layout architecture type.

[0122] In another aspect, this application also proposes a computer device, which includes a memory, a processor, and a processing program stored in the memory and executable on the processor. When the processing program is executed by the processor, it implements the above-mentioned method for setting the dynamic stiffness target of the suspension passive side support of a pure electric vehicle.

[0123] In another aspect, this application also proposes a storage medium storing a processing program, which, when executed by a processor, performs the above-described method for setting the dynamic stiffness target of the suspension passive side support of a pure electric vehicle.

[0124] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0125] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0126] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A method of setting a suspension passive side bracket dynamic stiffness target for a pure electric vehicle, characterized by, The method comprises: determining the position coordinates of the target suspension, the power assembly centroid position coordinates, the power assembly mass, the maximum torque of the motor, the speed ratio of the reducer, and the linear segment static stiffness of the target suspension in each direction; obtaining the static stiffness matrix of the target suspension according to the position coordinates of the target suspension, the power assembly centroid position coordinates, and the linear segment static stiffness; obtaining the power assembly displacement when the power assembly is subjected to the maximum torque according to the static stiffness matrix, the power assembly mass, the maximum torque of the motor, and the speed ratio of the reducer, and obtaining the force of the target suspension in each direction according to the power assembly displacement; obtaining the static stiffness curve of the target suspension in each direction to determine the slope at the suspension force position, which is the static stiffness at the suspension force position; obtaining the dynamic-static ratio of the target suspension in each direction at a preset frequency, obtaining the dynamic stiffness curve according to the dynamic-static ratio curve and the static stiffness at the suspension force position; According to the dynamic stiffness curve, the expected isolation efficiency coefficient and the project arrangement architecture type, a target suspension passive side support dynamic stiffness target is obtained, specifically comprising: multiplying the dynamic stiffness curve by the expected isolation efficiency coefficient to obtain an initial target suspension passive side support dynamic stiffness curve ; according to the project arrangement architecture type and the target suspension passive side support dynamic stiffness target is obtained: if the project arrangement architecture type is a load-bearing body, and there is no vibration isolation at the connection between the subframe mounting the power assembly and the vehicle body, the target suspension passive side support dynamic stiffness target is ; if the project arrangement architecture type is a load-bearing body, and there is vibration isolation at the connection between the subframe mounting the power assembly and the vehicle body, the target suspension passive side support dynamic stiffness target is ; if the project arrangement architecture type is a non-load-bearing body, the target suspension passive side support dynamic stiffness target is .

2. The method of claim 1, wherein, the calculation formula of the static stiffness matrix is: ， wherein K represents a static stiffness matrix, n represents a number of suspensions, T represents a matrix transpose, , x o , y o , z o represents a coordinate of a powertrain mass center position, x i , y i , z i represents a coordinate of an i-th suspension position, , k x represents an X-direction linear segment static stiffness of the i-th suspension, k y represents a Y-direction linear segment static stiffness of the i-th suspension, k z represents a Z-direction linear segment static stiffness of the i-th suspension.

3. The method of claim 2, wherein, the calculation formula of the power assembly displacement when the power assembly is subjected to the maximum torque is: ， wherein, Q represents the powertrain displacement, , m represents the powertrain mass, represents the motor maximum torque, W represents the reducer speed ratio.

4. The method of claim 3, wherein, the calculation formula of the force of the target suspension in each direction is: ， wherein, represents the force in the i-th suspended direction.

5. The method of claim 4, wherein, the calculation formula of the slope at the suspension force position is: ， wherein (F , ) and (F , ) represent the adjacent two coordinate points of the suspension force F at the corresponding points of the static stiffness curve, respectively.

6. The method of claim 5, wherein, the empirical formula is: ， wherein, represents a motion-to-quiet curve, B represents a motion-to-quiet ratio, and f represents a preset frequency. the calculation formula of the dynamic stiffness curve is: ， wherein represents the dynamic stiffness curve.

7. A suspension passive side support dynamic stiffness target setting system for a pure electric vehicle model, characterized by, The system comprises: a suspension data acquisition module configured to determine the position coordinates of the target suspension, the power assembly centroid position coordinates, the power assembly mass, the maximum torque of the motor, the speed ratio of the reducer, and the linear segment static stiffness of the target suspension in each direction; a data matrix module configured to obtain the static stiffness matrix of the target suspension according to the position coordinates of the target suspension, the power assembly centroid position coordinates, and the linear segment static stiffness; a suspension force determination module configured to obtain the power assembly displacement when the power assembly is subjected to the maximum torque according to the static stiffness matrix, the power assembly mass, the maximum torque of the motor, and the speed ratio of the reducer, and obtain the force of the target suspension in each direction according to the power assembly displacement; a suspension static stiffness determination module configured to obtain the static stiffness curve of the target suspension in each direction to determine the slope at the suspension force position, which is the static stiffness at the suspension force position; a suspension dynamic stiffness determination module configured to obtain the dynamic-static ratio of the target suspension in each direction at a preset frequency, obtain the dynamic stiffness curve according to the dynamic-static ratio curve and the static stiffness at the suspension force position; The support dynamic stiffness determination module is configured to obtain a target suspension passive side support dynamic stiffness target according to the dynamic stiffness curve, a desired isolation efficiency coefficient and a project arrangement architecture type, and specifically includes: multiplying the dynamic stiffness curve by the desired isolation efficiency coefficient to obtain an initial target suspension passive side support dynamic stiffness curve ; judging the target suspension passive side support dynamic stiffness target according to the project arrangement architecture type and the : if the project arrangement architecture type is a load-bearing body, and there is no vibration isolation at the connection between the subframe mounting the power assembly and the vehicle body, the target suspension passive side support dynamic stiffness target is ; if the project arrangement architecture type is a load-bearing body, and there is vibration isolation at the connection between the subframe mounting the power assembly and the vehicle body, the target suspension passive side support dynamic stiffness target is ; if the project arrangement architecture type is a non-load-bearing body, the target suspension passive side support dynamic stiffness target is .

8. A computer device, comprising: The computer device comprises a memory, a processor, and a processing program stored on the memory and executable on the processor, and the processing program is executed by the processor to implement the method in any one of claims 1 to 6.

9. A storage medium, characterized by The storage medium stores a processing program, and the processing program is executed by the processor to implement the method in any one of claims 1 to 6.

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