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

Abstract

The invention belongs to the technical field of vehicle vibration and noise control, and discloses a pure electric vehicle type suspension passive side support dynamic stiffness target setting method and system.The method comprises the steps that firstly, relevant parameters of a target suspension are determined, and the relevant parameters comprise position coordinates, the power assembly mass center position, mass and the like; then, a static stiffness matrix of the target suspension is obtained through calculation; then, the displacement of the power assembly at the maximum torque and the stress condition of the target suspension are analyzed; a static stiffness curve of the target suspension is obtained, and a dynamic stiffness curve is obtained by combining the dynamic-static ratio curve; and finally, according to the dynamic stiffness curve, the isolation efficiency coefficient and the project layout type, setting a dynamic stiffness target of the target suspension passive side bracket. According to the method, the influence of factors such as motor torque, suspension rigidity and arrangement architecture can be fully considered, and a reasonable suspension passive end support dynamic rigidity target is obtained to effectively control the howling level of the pure electric sample vehicle.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle vibration and noise control, and in particular relates to a method and system for setting a dynamic stiffness target of a passive side bracket of a pure electric vehicle. Background Art

[0002] With the development of society and the country'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, there is a big difference between the excitation source of pure electric vehicles and traditional fuel vehicles. The excitation frequency of traditional fuel vehicles is mainly low-frequency, while the excitation frequency of pure electric vehicles is mainly high-frequency, which can easily produce various harsh whistles, reducing the user experience of pure electric vehicles. Therefore, how to control the whistling level of pure electric vehicles has become the focus of research by various automobile manufacturers.

[0003] At the digital prototype stage, the squeal target of pure electric vehicles is decomposed. The dynamic stiffness of the passive side bracket of the suspension is one of the key factors in controlling the squeal of the whole vehicle, so how to reasonably formulate the dynamic stiffness target of the passive side bracket of the suspension has become a more critical issue. If the dynamic stiffness is too low, it may cause greater vibration of the vehicle body, thereby causing squealing; 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] At present, many OEMs mainly use the data of basic vehicles and competitive vehicles to formulate a target value for the dynamic stiffness of the passive side bracket of the suspension. In addition, some projects do not have corresponding basic vehicles and competitive vehicles, so an empirical value is provided as a target. Such target formulation does not take into account some factors of the project itself, resulting in a lack of rationality in the target. The existing target setting for the dynamic stiffness of the passive side bracket of the pure electric vehicle suspension does not take into account the influence of factors such as motor torque, suspension stiffness, and layout structure. It is difficult to obtain a reasonable target for the dynamic stiffness of the passive side bracket of the suspension to effectively control the howling level of the pure electric prototype vehicle. Summary of the invention

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

[0006] A first aspect of the present application provides a method for setting a dynamic stiffness target of a passive side bracket of a pure electric vehicle suspension, the method comprising: Determine the position coordinates of the target suspension, the position coordinates of the powertrain mass center, the powertrain mass, the maximum torque of the motor, the speed ratio of the reducer, and the linear segment static stiffness of the target suspension in all directions; Obtaining a static stiffness matrix of the target suspension according to the position coordinates of the target suspension, the position coordinates of the center of mass of the powertrain, and the linear segment static stiffness; According to the static stiffness matrix, the powertrain mass, the maximum torque of the motor and the speed ratio of the reducer, the powertrain displacement when the powertrain is subjected to the maximum torque is obtained, and the forces in various directions of the target suspension are obtained according to the powertrain displacement; Obtaining the static stiffness curve of the target suspension in each direction to determine the slope of the suspension where the force is applied, wherein the slope is the static stiffness of the suspension where the force is applied; Obtaining the dynamic-static ratio of the target suspension in each direction at a preset frequency, obtaining a dynamic-static ratio curve through an empirical formula, and obtaining a dynamic stiffness curve according to the dynamic-static ratio curve and the static stiffness of the suspension force-bearing position; The target suspension passive side bracket dynamic stiffness target is obtained according to the dynamic stiffness curve, the expected isolation efficiency coefficient and the project layout architecture type.

[0007] Compared with the prior art, the present application provides a method for setting the target dynamic stiffness of the passive side bracket of a pure electric vehicle suspension. The method can construct a static stiffness matrix by determining the position coordinates of the target suspension, the position coordinates of the powertrain center of mass, and the linear segment static stiffness 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 and provides a basis for subsequent dynamic analysis; using the static stiffness matrix, the powertrain mass, the maximum torque of the motor, and the speed ratio of the reducer, the displacement of the powertrain under the maximum torque can be calculated. Through the powertrain displacement, the force conditions in each direction of the target suspension can be further obtained, which helps to evaluate the stress state of the suspension when it bears the weight and torque of the powertrain; through experimental 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, through experimental or theoretical calculations, the target suspension is obtained. The dynamic-static ratio of the suspension in each direction is the ratio of the dynamic stiffness of the suspension to the static stiffness, which reflects the stiffness characteristics of the suspension under dynamic conditions. According to the empirical formula, the dynamic-static ratio curve can be drawn, which describes the change of the dynamic-static ratio of the suspension at different frequencies; the dynamic stiffness curve of the suspension can be calculated by using the dynamic-static ratio curve and the static stiffness of the force-bearing part of the suspension. The dynamic stiffness curve describes the stiffness characteristics of the suspension under dynamic conditions and is the key to evaluating the dynamic performance of the suspension; according to the dynamic stiffness curve, the expected isolation efficiency coefficient and the project layout architecture type, the dynamic stiffness target of the passive side bracket of the target suspension can be determined. The expected isolation efficiency coefficient reflects the effect of the suspension on vibration isolation, while the project layout architecture type affects the dynamic response of the suspension. Therefore, this method fully considers the influence of factors such as motor torque, suspension stiffness and layout architecture, and obtains a reasonable dynamic stiffness target of the passive side bracket of the suspension to effectively control the howling level of the pure electric prototype. In addition, the dynamic stiffness target of the passive side bracket of the pure electric vehicle is effectively set, thereby optimizing the dynamic performance of the suspension and improving the comfort and stability of the whole vehicle.

[0008] As an optional implementation of the first aspect, the calculation formula of the static stiffness matrix is: , Where K represents the static stiffness matrix, n represents the number of suspensions, and T represents the matrix transpose. , ( x o , y o , z o ) represents the coordinates of the powertrain center of mass, ( x i , y i , z i) represents the position coordinates of the i-th suspension, , k x represents the static stiffness of the linear segment in the X direction of the i-th suspension, k y represents the static stiffness of the Y-direction linear segment of the i-th suspension, k z represents the static stiffness of the Z-direction linear segment of the i-th suspension.

[0009] As an optional implementation manner of the first aspect, a calculation formula for the powertrain displacement when the powertrain is subjected to maximum torque is: , in, Q represents the powertrain displacement, , m represents the powertrain mass, It indicates the maximum torque of the motor, and W indicates the speed ratio of the reducer.

[0010] As an optional implementation manner of the first aspect, a calculation formula for the force in each direction of the target suspension is: , in, Represents the forces in all directions on the i-th suspension.

[0011] As an optional implementation manner of the first aspect, the calculation formula of the slope of the suspension force point is: , in,( , )and( , ) represent the two adjacent coordinate points of the corresponding points of the suspension force F on the static stiffness curve.

[0012] As an optional implementation manner of the first aspect, the empirical formula is: , in, Indicates the dynamic-static ratio curve, B indicates the dynamic-static ratio, and f indicates the preset frequency; The calculation formula of the dynamic stiffness curve is: , in, Represents the dynamic stiffness curve.

[0013] As an optional implementation of the first aspect, the step of obtaining a target suspension passive side bracket dynamic stiffness target according to the dynamic stiffness curve, the expected isolation efficiency coefficient and the project layout architecture type includes: The dynamic stiffness curve is multiplied by the expected isolation efficiency coefficient to obtain the initial target suspension passive side bracket dynamic stiffness curve: ; According to the project layout architecture type judgment and Get the target suspension passive side bracket dynamic stiffness target: If the project layout structure type is a load-bearing body, and there is no vibration isolation at the connection between the subframe where the powertrain is installed and the body, the target suspension passive side bracket dynamic stiffness target is ; If the project layout structure type is a load-bearing body, and there is vibration isolation at the connection between the subframe where the powertrain is installed and the body, the target suspension passive side bracket dynamic stiffness target is ; If the project layout structure type is a non-load-bearing body, the target suspension passive side bracket dynamic stiffness target is .

[0014] A second aspect of an embodiment of the present application provides a system for setting a dynamic stiffness target of a passive side bracket of a pure electric vehicle suspension, the system comprising: A suspension data acquisition module is used to determine the position coordinates of the target suspension, the position coordinates of the powertrain mass center, the powertrain mass, the maximum torque of the motor, the speed ratio of the reducer, and the linear segment static stiffness of the target suspension in all directions; A data matrixing module, used for obtaining a static stiffness matrix of the target suspension according to 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; A suspension force determination module, used to obtain the powertrain displacement when the powertrain is subjected to the maximum torque according to the static stiffness matrix, the powertrain mass, the maximum torque of the motor and the speed ratio of the reducer, and obtain the force of the target suspension in various directions according to the powertrain displacement; A suspension static stiffness determination module, used to obtain the static stiffness curves of the target suspension in various directions to determine the slope of the suspension force-bearing location, where the slope is the static stiffness of the suspension force-bearing location; A suspension dynamic stiffness determination module, used to obtain the dynamic-static ratio of the target suspension in each direction at a preset frequency, obtain a dynamic-static ratio curve through an empirical formula, and obtain a dynamic stiffness curve according to the dynamic-static ratio curve and the static stiffness of the suspension force-bearing position; The bracket dynamic stiffness determination module is used to obtain the target suspension passive side bracket dynamic stiffness target according to the dynamic stiffness curve, the expected isolation efficiency coefficient and the project layout architecture type.

[0015] A third aspect of an embodiment of the present application provides 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, the method for setting the dynamic stiffness target of the passive side bracket of the suspension of the above-mentioned pure electric vehicle is implemented.

[0016] A fourth aspect of an embodiment of the present application provides a storage medium having a processing program stored thereon. When the processing program is executed by a processor, the above-mentioned method for setting a dynamic stiffness target of a passive side bracket of a suspension of a pure electric vehicle is executed.

[0017] Additional aspects and advantages of the present application will be given in part in the following description, and in part will become apparent from the following description, or will be understood through the embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A flow chart of a method for setting a dynamic stiffness target of a passive side bracket of a pure electric vehicle suspension proposed in the first embodiment of the present application; Figure 2 This is a schematic diagram of the powertrain layout of the pure electric vehicle project in the second embodiment of the present application; Figure 3 This is the Z-direction static stiffness curve of the right suspension of a pure electric vehicle model in the second embodiment of this application; Figure 4 The right suspension Z-direction dynamic-static ratio curve of a pure electric vehicle model in the second embodiment of the present application; Figure 5 The target curve of the Z-direction dynamic stiffness of the right suspension passive side bracket of a pure electric vehicle model project in the second embodiment of the present application; Figure 6 The 24th-order noise of the main driving motor in a real vehicle of a pure electric vehicle model project in the second embodiment of this application; Figure 7 The Z-direction dynamic stiffness of the right suspension passive side bracket of a pure electric vehicle model project in the second embodiment of the present application; Figure 8 This is a comparison of the Z-direction dynamic stiffness of the right suspension passive side bracket of a pure electric vehicle project before and after optimization in the second embodiment of this application; Fig. 9 This is a comparison before and after the 24th-order noise optimization of the in-vehicle motor of a real vehicle of a pure electric vehicle model project in the second embodiment of this application; Fig.10 This is a schematic structural diagram of a dynamic stiffness target setting system for a passive side bracket of a pure electric vehicle suspension proposed in the third embodiment of the present application.

[0019] The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions 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 creative work are within the scope of protection of this application.

[0021] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here. In addition, the "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally represents that the objects associated with each other are in an "or" relationship.

[0022] In order to illustrate the technical solution described in this application, a specific embodiment is provided below for illustration.

[0023] Example 1 See also Figure 1 , is a flow chart of a method for setting a dynamic stiffness target of a passive side bracket of a pure electric vehicle suspension proposed in the first embodiment of the present application, and the proposed method includes: S01: Determine the position coordinates of the target suspension, the position coordinates of the center of mass of the powertrain, the mass of the powertrain, 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.

[0024] S02: obtaining a static stiffness matrix of the target suspension according to 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; It should be noted that the static stiffness matrix provides designers with stiffness distribution information of the suspension system, which helps to optimize the design stage 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 vehicle. By monitoring and analyzing the static stiffness matrix, abnormal changes in the suspension system can be discovered in a timely manner, assisting fault diagnosis and maintenance decisions.

[0025] Specifically, the calculation formula of the static stiffness matrix of the target mount is: (1) Where K represents the static stiffness matrix, n represents the number of suspensions, and T represents the matrix transpose. , ( xo , y o , z o ) represents the coordinates of the powertrain center of mass, ( x i , y i , z i ) represents the position coordinates of the i-th suspension, , k x represents the static stiffness of the linear segment in the X direction of the i-th suspension, k y represents the static stiffness of the Y-direction linear segment of the i-th suspension, k z represents the static stiffness of the Z-direction linear segment of the i-th suspension.

[0026] S03: According to the static stiffness matrix, the powertrain mass, the maximum torque of the motor and the speed ratio of the reducer, the powertrain displacement when the powertrain is subjected to the maximum torque is obtained, and the forces in various directions of the target suspension are obtained according to the powertrain displacement.

[0027] Specifically, the calculation formula of the powertrain displacement when the powertrain is subjected to the maximum torque is: (2) in, Q represents the powertrain displacement, , m represents the powertrain mass, It indicates the maximum torque of the motor, and W indicates the speed ratio of the reducer.

[0028] Furthermore, the calculation formula of the force in each direction of the target suspension is: (3) in, Represents the forces in all directions on the i-th suspension.

[0029] In this step, the displacement of the powertrain when it is subjected to the maximum torque is calculated to further obtain the forces in all directions of the target suspension. This result is very important for the design and optimization of the suspension system, because it can help engineers determine the support force and stiffness that the suspension system needs to provide to ensure the stability and reliability of the powertrain under various working conditions. In addition, by analyzing the forces in all directions of the target suspension, the vibration reduction effect of the suspension system can also be evaluated, providing a basis for further improving the suspension system.

[0030] S04: Obtain the static stiffness curve of the target suspension in each direction to determine the slope of the suspension where the force is applied, and the slope is the static stiffness of the suspension where the force is applied.

[0031] It can be understood that static stiffness is one of the important indicators to measure the performance of the suspension system, which reflects the ability of the suspension to resist deformation when subjected to force. By obtaining static stiffness curves in different directions, the stiffness characteristics of the suspension in various directions can be understood, thereby providing guidance for designing appropriate suspension structures and parameters, and the static stiffness curve is usually provided by the suspension supplier. In addition, the determination of the slope can also help engineers evaluate the stress conditions of the suspension system and provide a basis for the selection of materials and installation locations for the suspension.

[0032] Specifically, the calculation formula of the slope of the suspension force is: (4) in,( , )and( , ) represent the two adjacent coordinate points of the corresponding points of the suspension force F on the static stiffness curve.

[0033] S05: Obtaining the dynamic-static ratio of the target suspension in each direction at a preset frequency, obtaining a dynamic-static ratio curve through an empirical formula, and obtaining a dynamic stiffness curve according to the dynamic-static ratio curve and the static stiffness of the suspension force receiving location.

[0034] It is understandable that the dynamic-static ratio is an important parameter that describes the dynamic and static stress conditions of the suspension. By obtaining the dynamic-static ratio curves in different directions, the dynamic performance of the suspension can be fully understood, and the dynamic-static ratio is usually provided by the suspension supplier. The application of empirical formulas can be fitted and corrected according to actual conditions, which improves the accuracy and reliability of the dynamic-static ratio curve. The dynamic stiffness curve further reflects the stiffness characteristics of the suspension under dynamic loads, which is of great significance for evaluating the vibration reduction effect and structural stability of the suspension. By combining the dynamic-static ratio curve and the static stiffness, the dynamic response of the suspension in actual work can be more accurately predicted, providing strong support for the design and optimization of the suspension.

[0035] Specifically, the empirical formula is: (5) in, Indicates the dynamic-static ratio curve, B indicates the dynamic-static ratio, and f indicates the preset frequency; Furthermore, the calculation formula of the dynamic stiffness curve is: (6) in, Represents the dynamic stiffness curve.

[0036] S06: Obtaining a target suspension passive side bracket dynamic stiffness target according to the dynamic stiffness curve, the expected isolation efficiency coefficient and the project layout architecture type.

[0037] It can be understood that through the dynamic stiffness curve, the dynamic characteristics of the suspension system at different frequencies can be intuitively understood, providing a reference for the design. The expected isolation efficiency coefficient reflects the isolation effect of the suspension system within a specific frequency range, which helps to optimize the suspension parameters and improve the comfort and handling of the vehicle. In this method, considering that the dynamic stiffness between the passive side brackets of the target suspension must play an effective vibration isolation and noise reduction effect, the target suspension dynamic stiffness is usually multiplied by the expected isolation efficiency coefficient. According to empirical verification, this expected isolation efficiency coefficient is usually 3, which is more reasonable. The project layout architecture type determines the layout and connection method of the suspension system, which has an important influence on the determination of the dynamic stiffness target. By comprehensively considering these factors, the dynamic stiffness target of the passive side bracket of the target suspension can be determined more accurately, providing a basis for subsequent design and optimization.

[0038] Specifically, the dynamic stiffness curve is multiplied by the expected isolation efficiency coefficient to obtain the initial target suspension passive side bracket dynamic stiffness curve: ; According to the project layout architecture type judgment and Get the target suspension passive side bracket dynamic stiffness target: If the project layout structure type is a load-bearing body (chassis is directly installed on the body, without a frame), and there is no vibration isolation at the connection between the subframe where the powertrain is installed and the body, the target suspension passive side bracket dynamic stiffness target is ; If the project layout structure type is a load-bearing body (chassis is directly installed on the body, without a frame), and there is vibration isolation at the connection between the subframe where the powertrain is installed and the body, the target suspension passive side bracket dynamic stiffness target is ; If the project layout structure type is a non-load-bearing body (with a frame), the target suspension passive side bracket dynamic stiffness target is .

[0039] In summary, this method can construct a static stiffness matrix by determining the position coordinates of the target suspension, the position coordinates of the powertrain center of mass, and the linear segment static stiffness of the target suspension in all directions. This matrix describes the stiffness characteristics of the target suspension in all directions. The construction of the static stiffness matrix helps to understand the mechanical behavior of the suspension under static conditions and provides a basis for subsequent dynamic analysis; using the static stiffness matrix, powertrain mass, motor maximum torque, and reducer speed ratio, the powertrain displacement under the maximum torque can be calculated. Through the powertrain displacement, the force conditions in all directions of the target suspension can be further obtained, which helps to evaluate the stress state of the suspension when it bears the weight and torque of the powertrain; through experimental or theoretical analysis, the static stiffness curves of the target suspension in all directions are obtained. These curves describe the changes in the static stiffness of the suspension under different displacements; at a preset frequency, the target suspension is obtained through experiments or theoretical calculations. The dynamic-static ratio of the suspension in each direction is the ratio of the dynamic stiffness of the suspension to the static stiffness, which reflects the stiffness characteristics of the suspension under dynamic conditions. According to the empirical formula, the dynamic-static ratio curve can be drawn, which describes the change of the dynamic-static ratio of the suspension at different frequencies; the dynamic stiffness curve of the suspension can be calculated by using the dynamic-static ratio curve and the static stiffness of the force-bearing part of the suspension. The dynamic stiffness curve describes the stiffness characteristics of the suspension under dynamic conditions and is the key to evaluating the dynamic performance of the suspension; according to the dynamic stiffness curve, the expected isolation efficiency coefficient and the project layout architecture type, the dynamic stiffness target of the passive side bracket of the target suspension can be determined. The expected isolation efficiency coefficient reflects the effect of the suspension on vibration isolation, while the project layout architecture type affects the dynamic response of the suspension. Therefore, this method fully considers the influence of factors such as motor torque, suspension stiffness and layout architecture, and obtains a reasonable dynamic stiffness target of the passive side bracket of the suspension to effectively control the howling level of the pure electric prototype. In addition, the dynamic stiffness target of the passive side bracket of the pure electric vehicle is effectively set, thereby optimizing the dynamic performance of the suspension and improving the comfort and stability of the whole vehicle.

[0040] Example 2 The second embodiment of the present application proposes a method for setting a target dynamic stiffness of a passive side bracket of a pure electric vehicle: S001: The powertrain layout of a pure electric vehicle is as follows: Figure 2 As shown in Table 1, the powertrain mass, powertrain center of mass position coordinates, motor maximum torque, reducer speed ratio, suspension position coordinates and linear segment static stiffness data of a pure electric vehicle project are collected. The suspension forces in three directions of the three suspensions when the powertrain is subjected to the maximum torque are calculated by formulas (1), (2) and (3). Table 2 shows that the right suspension force in the Z direction is 4977N. Table 1 Collection of parameters required for calculating suspension forces for a pure electric vehicle project Table 2 Suspension force of a pure electric vehicle project when the powertrain is subjected to maximum torque S002: Figure 3 is the static stiffness curve of the right suspension in the Z direction, and according to formula (4), the slope of the static stiffness curve when the suspension force is 4977N is 1593N / mm, that is, the static stiffness of the right suspension when the Z direction force is 4977N is 1593N / mm.

[0041] S003: The dynamic-static ratio of the right suspension in the Z direction at 2 Hz is 1.5. According to the empirical formula (5), the dynamic-static ratio curve from 100 Hz to 1200 Hz is as follows: Figure 4 shown.

[0042] S004: According to formula (6), 1593N / mm is multiplied by the dynamic-static ratio curve to obtain the suspension dynamic stiffness curve, which is then multiplied by the expected isolation efficiency coefficient 3 to obtain the P(f) curve. In addition, the pure electric project is a load-bearing body and there is no vibration isolation at the connection between the subframe where the powertrain is installed and the body. Therefore, the P(f) curve is the target dynamic stiffness curve of the passive side bracket of the suspension, such as Figure 5 shown.

[0043] Demonstration by Example Taking the above-mentioned pure electric project as an example, the rationality of the method of the present invention is explained and demonstrated.

[0044] When a pure electric vehicle accelerates at full throttle, the driver's noise in the car is obvious and unacceptable. The test data shows that the howling is mainly contributed by the 24th order of the motor, such as Figure 6 As shown, the problem frequency is around 850Hz, reaching 45dBA, while the target is 40 dBA, which does not meet the target.

[0045] After investigation, it was determined that the main cause of the problem was the low Z-direction dynamic stiffness of the right suspension passive side bracket. Figure 7 As shown, the dynamic stiffness of the right passive side bracket of the suspension is about 5300N / mm at a frequency of about 850Hz, which meets the target of 5000N / mm established through experience in the digital prototype stage of the project, but does not meet the dynamic stiffness curve of the passive side bracket of the suspension established by the method of the present invention ( Figure 5 curve); The Z-direction dynamic stiffness of the right suspension passive side bracket is analyzed and optimized by CAE. The Z-direction dynamic stiffness of the right suspension passive side bracket has met the dynamic stiffness target set by the method of the present invention, such as Figure 8 As shown in the figure, and verified by real vehicle, the 24th order noise of the main driving motor in the car is significantly optimized under full throttle acceleration conditions, such as Fig. 9 As shown, the in-vehicle noise target is met and is subjectively acceptable, which indicates that the dynamic stiffness target of the passive side bracket of the suspension formulated by the method of the present invention is reasonable.

[0046] Example 3 See also Fig.10 , which is a schematic diagram of the structure of a passive side bracket dynamic stiffness target setting system for a pure electric vehicle suspension proposed in the third embodiment of the present application, and the system includes: The suspension data acquisition module 10 is used to determine the position coordinates of the target suspension, the position coordinates of the center of mass of the powertrain, the mass of the powertrain, 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 matrixing module 20, for obtaining a static stiffness matrix of the target suspension according to 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; The suspension force determination module 30 is used to obtain the powertrain displacement when the powertrain is subjected to the maximum torque according to the static stiffness matrix, the powertrain 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 powertrain displacement; The suspension static stiffness determination module 40 is used to obtain the static stiffness curves of the target suspension in various directions to determine the slope of the suspension force-bearing part, and the slope is the static stiffness of the suspension force-bearing part; The suspension dynamic stiffness determination module 50 is used to obtain the dynamic-static ratio of the target suspension in each direction at a preset frequency, obtain a dynamic-static ratio curve through an empirical formula, and obtain a dynamic stiffness curve according to the dynamic-static ratio curve and the static stiffness of the suspension force receiving part; The bracket dynamic stiffness determination module 60 is used to obtain a target suspension passive side bracket dynamic stiffness target according to the dynamic stiffness curve, the expected isolation efficiency coefficient and the project layout architecture type.

[0047] On the other hand, the present 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, the method for setting the dynamic stiffness target of the passive side bracket of the suspension of the above-mentioned pure electric vehicle is implemented.

[0048] On the other hand, the present application further proposes a storage medium, on which a processing program is stored. When the processing program is run by a processor, the method for setting the dynamic stiffness target of the passive side bracket of the suspension of the pure electric vehicle is executed.

[0049] It should be noted that, in this article, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also includes 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 one..." do not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0050] 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, 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, a magnetic disk, or an optical disk), and includes a number of instructions for a terminal (which can be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to execute the methods described in each embodiment of the present application.

[0051] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A method for setting the dynamic stiffness target of a passive side bracket of a pure electric vehicle suspension, characterized in that: The method comprises: Determine the position coordinates of the target suspension, the position coordinates of the powertrain mass center, the powertrain mass, the maximum torque of the motor, the speed ratio of the reducer, and the linear segment static stiffness of the target suspension in all directions; Obtaining a static stiffness matrix of the target suspension according to the position coordinates of the target suspension, the position coordinates of the center of mass of the powertrain, and the linear segment static stiffness; According to the static stiffness matrix, the powertrain mass, the maximum torque of the motor and the speed ratio of the reducer, the powertrain displacement when the powertrain is subjected to the maximum torque is obtained, and the forces in various directions of the target suspension are obtained according to the powertrain displacement; Obtaining the static stiffness curve of the target suspension in each direction to determine the slope of the suspension where the force is applied, wherein the slope is the static stiffness of the suspension where the force is applied; Obtaining the dynamic-static ratio of the target suspension in each direction at a preset frequency, obtaining a dynamic-static ratio curve through an empirical formula, and obtaining a dynamic stiffness curve according to the dynamic-static ratio curve and the static stiffness of the suspension force-bearing position; The target suspension passive side bracket dynamic stiffness target is obtained according to the dynamic stiffness curve, the expected isolation efficiency coefficient and the project layout architecture type.

2. The method according to claim 1, characterized in that: The calculation formula of the static stiffness matrix is: ， Where K represents the static stiffness matrix, n represents the number of suspensions, and T represents the matrix transpose. , ( x o , y o , z o ) represents the coordinates of the powertrain center of mass, ( x i , y i , z i ) represents the position coordinates of the i-th suspension, , k x represents the static stiffness of the linear segment in the X direction of the i-th suspension, k y represents the static stiffness of the Y-direction linear segment of the i-th suspension, k z represents the static stiffness of the Z-direction linear segment of the i-th suspension.

3. The method according to claim 2, characterized in that: The calculation formula of the powertrain displacement when the powertrain is subjected to the maximum torque is: ， in, Q represents the powertrain displacement, , m represents the powertrain mass, It indicates the maximum torque of the motor, and W indicates the speed ratio of the reducer.

4. The method according to claim 3, characterized in that: The calculation formula of the force in each direction of the target suspension is: ， in, Represents the forces in all directions on the i-th suspension.

5. The method according to claim 4, characterized in that: The calculation formula of the slope of the suspension force is: ， in,( , )and( , ) represent the two adjacent coordinate points of the corresponding points of the suspension force F on the static stiffness curve.

6. The method according to claim 5, characterized in that: The empirical formula is: ， in, Indicates the dynamic-static ratio curve, B indicates the dynamic-static ratio, and f indicates the preset frequency; The calculation formula of the dynamic stiffness curve is: ， in, Represents the dynamic stiffness curve.

7. The method according to claim 1, characterized in that: The step of obtaining a target suspension passive side bracket dynamic stiffness target according to the dynamic stiffness curve, the expected isolation efficiency coefficient and the project layout architecture type comprises: The dynamic stiffness curve is multiplied by the expected isolation efficiency coefficient to obtain the initial target suspension passive side bracket dynamic stiffness curve: ; According to the project layout architecture type judgment and Get the target suspension passive side bracket dynamic stiffness target: If the project layout structure type is a load-bearing body, and there is no vibration isolation at the connection between the subframe where the powertrain is installed and the body, the target suspension passive side bracket dynamic stiffness target is ; If the project layout structure type is a load-bearing body, and there is vibration isolation at the connection between the subframe where the powertrain is installed and the body, the target suspension passive side bracket dynamic stiffness target is ; If the project layout structure type is a non-load-bearing body, the target suspension passive side bracket dynamic stiffness target is .

8. The passive side bracket dynamic stiffness target setting system for pure electric vehicle suspension is characterized by: The system comprises: A suspension data acquisition module is used to determine the position coordinates of the target suspension, the position coordinates of the powertrain mass center, the powertrain mass, the maximum torque of the motor, the speed ratio of the reducer, and the linear segment static stiffness of the target suspension in all directions; A data matrixing module, used for obtaining a static stiffness matrix of the target suspension according to 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; A suspension force determination module, used to obtain the powertrain displacement when the powertrain is subjected to the maximum torque according to the static stiffness matrix, the powertrain mass, the maximum torque of the motor and the speed ratio of the reducer, and obtain the force of the target suspension in various directions according to the powertrain displacement; A suspension static stiffness determination module, used to obtain the static stiffness curves of the target suspension in various directions to determine the slope of the suspension force-bearing location, where the slope is the static stiffness of the suspension force-bearing location; A suspension dynamic stiffness determination module, used to obtain the dynamic-static ratio of the target suspension in each direction at a preset frequency, obtain a dynamic-static ratio curve through an empirical formula, and obtain a dynamic stiffness curve according to the dynamic-static ratio curve and the static stiffness of the suspension force-bearing position; The bracket dynamic stiffness determination module is used to obtain the target suspension passive side bracket dynamic stiffness target according to the dynamic stiffness curve, the expected isolation efficiency coefficient and the project layout architecture type.

9. A computer device, characterized in that: The computer device comprises a memory, a processor, and a processing program stored in the memory and executable on the processor, wherein the processing program implements the method according to any one of claims 1 to 7 when executed by the processor.

10. A storage medium, characterized in that: The storage medium stores a processing program, and the processing program implements the method according to any one of claims 1 to 7 when executed by a processor.

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