Macpherson suspension modeling method and system and storage medium

Abstract

The invention provides a Macpherson suspension modeling method and system and a storage medium, and relates to the technical field of Macpherson suspension modeling, and the method comprehensively captures the dynamic change and energy distribution condition of a suspension system by establishing a detailed nonlinear dynamic model and combining a Lagrange method with the kinematic characteristics of the suspension system. Compared with a 2DOF model in the prior art, the response characteristics of the suspension system under various complex working conditions can be described more accurately, the precision and practicability of the model are higher, the consumed resources and cost are lower, a more economical and rapid theoretical basis can be provided for design and performance analysis of the suspension, and the method is suitable for popularization and application. And an engineer can more effectively carry out suspension design optimization and control strategy development, so that the vehicle can keep excellent performance under different driving conditions.

Description

Technical Field

[0001] The invention relates to the technical field of MacPherson suspension modeling, and in particular to a MacPherson suspension modeling method, system and storage medium. Background Art

[0002] The suspension system is an important component of a car, and its performance is an important factor affecting the car's ride smoothness and handling stability. Establishing its mathematical model is the basis for studying and analyzing the vehicle's various driving performances.

[0003] Since the classic 2DOF model is simple and easy to build, most studies on suspension dynamics use the classic 2DOF model. Although this model can better reflect the vertical movement of the sprung mass and the unsprung mass, it fails to consider important factors that can affect the suspension performance, such as the tire camber angle and wheelbase. Changes in the camber angle will increase tire wear and cause the wheel to bear additional lateral force, which in turn causes the vehicle to deviate laterally. Changes in the castor angle and the kingpin inclination angle will have a significant impact on the vehicle's self-aligning torque, which is directly related to the vehicle's driving stability and handling performance during the wheel rolling process. When the vehicle is driving on an uneven road, the dynamic change of the wheelbase may cause the tire to slip during the rolling process, which will not only generate additional lateral force, but also may interfere with the vehicle's steering performance. In summary, reasonable vehicle motion parameter performance is of great significance for improving driving safety, optimizing steering operation convenience, extending tire service life, improving fuel efficiency, and reducing the stress load of the steering and suspension systems. Therefore, the McPherson suspension geometry induces nonlinear factors related to kinematics and dynamics that cannot be fuzzily analyzed using traditional methods.

[0004] In view of the shortcomings of the classic 2DOF model, scholars have continuously proposed new modeling methods. However, no modeling method can take into account the factors ignored in the classic 2DOF model, such as suspension geometry, control arm moment of inertia, tire moment of inertia, tire damping, tire lateral stiffness, nonlinear stiffness and damping characteristics. Therefore, it is necessary to provide a nonlinear model based on McPherson suspension that can accurately reflect the nonlinear dynamic behavior of the vehicle suspension system.

[0005] The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not constitute the prior art that is already known to one of ordinary skill in the art. Summary of the invention

[0006] The object of the present invention is to provide a modeling method, system and storage medium for a McPherson suspension to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A modeling method for a MacPherson suspension, the specific steps comprising:

[0009] S1: Draw the two-dimensional model diagram and plane motion diagram of the McPherson suspension, make simplified assumptions about the motion trajectory and physical properties of the McPherson suspension, and simplify the definitions of the various positions in the plane motion diagram corresponding to the McPherson suspension;

[0010] S2: Using the displacement matrix method and the first-order Taylor expansion formula, the kinematic analysis of the McPherson suspension is performed based on the geometric relationship in the plane kinematic diagram, the displacement matrix of the wheel displacement process is obtained, and the kinematic equation of the wheel displacement is generated based on the displacement matrix;

[0011] S3: define the key coordinate points on the plane motion diagram and the dynamic coordinates of the key coordinate points, linearly represent and solve the kinematic equation of wheel displacement, and construct the kinematic equation of wheel deflection displacement based on the solution results;

[0012] S4: Draw a schematic diagram of the elastic element, define the changes of the stiffness coefficient and the damping coefficient of the elastic element during movement, and construct the change equations corresponding to the stiffness coefficient and the damping coefficient respectively;

[0013] S5: Establish a nonlinear model, jointly solve the equations in steps S2 to S4, obtain the relationship between the correlation coefficients in the model and the unknown quantities in the equations, and construct a suspension dynamics model through the Lagrangian method.

[0014] Preferably, the correlation coefficient includes displacement, velocity and acceleration of key coordinate points; the unknown quantities in the equation include sprung mass displacement, unsprung mass displacement, sprung mass velocity, unsprung mass velocity, sprung mass acceleration and unsprung mass acceleration.

[0015] Preferably, in step S1, the simplified assumptions made for the motion trajectory and physical properties of the McPherson suspension are:

[0016] The sprung mass only moves vertically, all suspension system components except the wheels are rigid components, and the mass of the control arms and struts is negligible;

[0017] The simplified definitions of the various positions in the planar kinematic diagram corresponding to the MacPherson suspension include:

[0018] The sprung mass displacement is Z S , the sprung mass speed is The sprung mass acceleration is The displacement of the unsprung mass is Z U , the unsprung mass velocity is Unsprung mass acceleration The road disturbance displacement is Z r , the road disturbance speed is The key coordinate points of the suspension include the reference origin, the end point of the control arm, the lower end point of the elastic element, the center of the wheel, the upper end point of the elastic element, and the connection point between the frame and the elastic element, which are calibrated by the letters O, A, B, C, D, and E respectively; the X and Y axes of the global reference system represent the horizontal and vertical directions respectively; the BD segment is the elastic element, and the L segment is the elastic element. 03 is the sum of the initial lengths of the elastic element and the support, L 3 is the sum of the real-time lengths of the elastic element and the support during the movement, L 3 -L 03 is the change of the elastic element, OA is the control arm, L 1 is the length of the control arm, θ 0 is the angle between the control arm and the Y axis in the initial state, θ is the angle the control arm rotates during the movement, is the angle between the wheel axis and the vertical direction, L 2 is the length of line segment OE, and the state of the suspension is represented by two generalized coordinates corresponding to the degrees of freedom of the system.

[0019] Preferably, in step S2, the logic of kinematic analysis of the system is:

[0020] S21: The displacement of the wheel on the plane is regarded as rotation and translation, and the kinematic characteristics of the plane motion diagram are analyzed using the displacement matrix method, where the displacement matrix D wheel It is expressed as:

[0021]

[0022] where Y C and Z C is the instantaneous coordinate of the wheel center C, Y C0 and Z C0 Respectively represent Y C and Z C The initial equilibrium value, a 11 =a 22 =cosφ, Where φ is the deflection angle of the wheel around the X-axis, and cosφ≈1, sinφ≈φ;

[0023] In the initial equilibrium state, the key coordinate points of the suspension are located at points O, A, B, C, D, and E respectively. The instantaneous coordinates of points A, B, and D are calculated using the displacement matrix and calibrated as (Y A ,Z A )、(Y B ,Z B )、(Y D ,Z D), and the following equation is obtained:

[0024]

[0025] Where (Y A0 ,Z A0 )、(Y B0 ,Z B0 )、(Y D0 ,Z D0 ) represent the initial equilibrium coordinates of points A, B, and D respectively;

[0026] S22: Continue to perform kinematic analysis on the system and obtain the following equation:

[0027]

[0028] S23: Perform kinematic analysis on the control arm and obtain the following equation:

[0029] Y A =L 1 (cosθcosθ 0 -sinθsinθ 0 )

[0030] Z A =L 1 (sinθcosθ 0 +cosθsinθ 0 )+Z S

[0031] g=L 1 sinθ 0

[0032] h=-L 1 cosθ 0

[0033] S24: Simplify the equation in step S23 to obtain the following equation:

[0034] Y A +gθ=-h

[0035] S25: Since the control arm is a rigid component, the following equation is obtained:

[0036] (Y A -Y O ) 2 +(Z A -Z O ) 2 =L 1 2

[0037] S26: Reconstruct function F 1and function F 2 , let F 1 =(Y A -Y O ) 2 , F 2 =(Z A -Z O ) 2 , respectively for the function F 1 and function F 2 Perform a first-order Taylor expansion and linearize to obtain the following equation:

[0038] F 1 =(Y A0 -Y O0 ) 2 +2Y A0 (Y A -Y A0 )

[0039] F 2 =(Z A0 -Z O0 ) 2 +2(Z A0 -Z S )(Z A -Z A0 )-2Z A Z S

[0040] S27: Substitute the equation in step S26 into the equation in step S25 to obtain the following equation:

[0041] Y A0 Y A +(Z A0 -2Z S )Z A +Z A0 Z S =L 1 2 .

[0042] Preferably, in step S3, the logic for defining the dynamic coordinates of the key coordinate points on the plane motion graph is:

[0043] Steps S22, S24, and S27 define a set of equations with 11 unknown variables, using the sprung mass displacement Z S and the unsprung mass displacement Z U By linearizing it and solving the equation group, we can obtain the kinematic equations of the key variables of the suspension, as shown below:

[0044]

[0045] where a′=gYA0 +hZ A0 , b′=-2h, S=a′+b′Z S ;

[0046] Y C Simplifying, we get:

[0047]

[0048] in

[0049]

[0050] Take the first-order derivative of the Y-axis coordinate of the wheel center point C to get its lateral velocity Then take the second-order derivative to get its lateral acceleration Respectively expressed as:

[0051]

[0052] where j′=a′e′-d′b′, l′=a′ 2 f′-b′j′;

[0053] Define the following relationship:

[0054]

[0055] The wheel deflection angle Simplified to:

[0056]

[0057] Deflection angle of the wheel Calculate the derivative twice in succession to get the angular velocity and angular acceleration

[0058]

[0059] The deflection displacement of the wheel caused by the movement δY tl The formula is as follows:

[0060] δY tl =Y C -Y C0 -φR

[0061] Y C and Substitute the simplified equation into the deflection displacement δY tl And simplify it in the formula to get the following equation:

[0062]

[0063] in

[0064] Then, the partial derivative of the wheel deflection displacement with respect to the sprung mass displacement and the unsprung mass displacement is obtained:

[0065]

[0066] where m′=a′u′-b′t′.

[0067] Preferably, in step S4, the logic for defining the change of the stiffness coefficient and the damping coefficient of the elastic element during the movement is:

[0068] The elastic element consists of a piston rod and piston assembly, a one-way valve, a damping hole, and a cylinder. 1 is the pressure of the working chamber of the elastic element, V 1 is the gas volume of the working chamber of the elastic element, A 1 is the cross-sectional area of ​​the inner cavity of the elastic element cylinder, P 2 is the annular cavity pressure, A 2 The cross-sectional area of ​​the annular cavity, x is the working stroke of the elastic element;

[0069] During the working stroke of the elastic element, the piston rod is subjected to balanced force, and the equation for its output force F is:

[0070] F=P 1 A 1 -P 2 A 2

[0071] In equilibrium state, the state equation of the gas in the elastic element is:

[0072]

[0073] Where r is the gas polytropic index; V 10 , P 10 are the gas volume and pressure in the initial state of the working chamber of the elastic element, respectively;

[0074] Working chamber gas volume V 1 The relationship between the cylinder displacement x and the piston displacement x is:

[0075] V 1 =V 10 -(A 1 -A 2 )x

[0076] Solve the above equations to get the elastic force F k The expression equation of (x) is:

[0077]

[0078] Elastic force F k (x) Take the derivative and get the stiffness coefficient K of the elastic element s for:

[0079]

[0080] When solving the static stiffness of the elastic element, r is taken as 1, and when solving the dynamic stiffness of the elastic element, r is taken as 1.73;

[0081] The pressure difference ΔP between the working chamber and the annular chamber is:

[0082] ΔP=P 1 -P 2

[0083] The equation for the oil flow Q flowing through the damping orifice and the one-way valve is:

[0084]

[0085] Where C z , C d is the flow coefficient, A z , A d is the effective flow area, z is the relevant parameter of the damping hole, d is the relevant parameter of the one-way valve, and ρ is the density of the hydraulic oil;

[0086] During the operation of the elastic element, the relationship between the oil flow rate flowing in the two chambers and the relative speed between the piston rods is:

[0087]

[0088] The equation between the combined output force, pressure difference, oil flow rate, oil flow rate and piston rod is:

[0089]

[0090] In the formula represents the damping force generated by the suspension orifice, and:

[0091]

[0092] right The movement speed of the elastic element Derivative, get the damping coefficient B of the elastic element S , the calculation formula is:

[0093]

[0094] In the formula is a direction function. When the compression stroke is positive, the movement speed of the elastic element The function value is 1; when the compression stroke is negative, the movement speed of the elastic element The function value is -1;

[0095] Since the elastic element is in the geometric structure of the suspension, the following equation is obtained:

[0096] x=δl=L 3 -L 03 .

[0097] Preferably, in step S5, the logic of establishing the nonlinear model is:

[0098] The Lagrangian method is used to establish the vehicle dynamics equation, where the expressions of the suspension's kinetic energy T, potential energy V, and dissipated energy D are as follows:

[0099]

[0100] Where m S and m U are the chassis and wheel masses of the vehicle, I C represents the wheel inertia around the X axis, K S is the stiffness of the elastic element, K t and K tl They represent the vertical stiffness and lateral stiffness of the wheel, R is the effective radius of the wheel, and B S and B t They represent the damping coefficients of the suspension and wheels respectively, and δl is the working stroke of the elastic element;

[0101] Applying the law of cosines to the triangle OAE yields:

[0102] 2L 1 L 2 cosγ 0 =(L 1 ) 2 +(L 2 ) 2 -(L 03 ) 2

[0103] 2L 1 L 2 cos(γ 0 +θ)=(L 1 ) 2 +(L 2 ) 2 -(L 3 ) 2

[0104] The angle θ of the control arm rotation is small, so cosθ≈1, sinθ≈θ;

[0105] Combining the above equation with the law of cosines, we get:

[0106] (L 3 ) 2 =(L 03 ) 2 +kθ

[0107] k=-2L 1 L 2 sinγ 0

[0108] The working stroke of the elastic element is expressed as:

[0109]

[0110] Let B = (L 03 ) 2 + kθ, we get:

[0111]

[0112] δZ t =Z U -Z r

[0113] Applying the Lagrangian dynamics equation, we get:

[0114]

[0115] Combined with the wheel deflection displacement, the partial derivative equations of the sprung mass displacement and the unsprung mass displacement, the dissipated energy equation, δZ t The expression equation of , and the Lagrangian dynamics equation of the above formula, get the final expression:

[0116]

[0117] The above two equations are the final mathematical expressions of the nonlinear model, completing the establishment of the nonlinear model.

[0118] Preferably, the elastic element includes an oil-gas spring, an air spring, or a coil spring.

[0119] A modeling system based on a MacPherson suspension, the modeling system being used to execute the above-mentioned modeling method, comprising:

[0120] An image drawing module, wherein the image drawing module is used to draw a two-dimensional image and a plane motion image of the McPherson suspension, as well as a schematic diagram of the elastic element, and to add characters to the two-dimensional image and the plane motion image of the McPherson suspension, as well as the schematic diagram of the elastic element for calibration;

[0121] A first analysis module, wherein the first analysis module is used to perform kinematic analysis on the entire McPherson suspension according to a two-dimensional diagram and a planar kinematic diagram of the McPherson suspension, and obtain a corresponding kinematic equation;

[0122] A coordinate definition module, which is used to define and calculate the dynamic coordinates of the key coordinate points on the plane motion diagram of the McPherson suspension according to the kinematic equations obtained in the data analysis module, and obtain the corresponding coordinate equations;

[0123] A second analysis module, the second analysis module is used to define and calculate the changes of the stiffness coefficient and the damping coefficient of the elastic element during the movement according to the elastic element schematic diagram, and obtain the corresponding change equation;

[0124] The comprehensive processing module is used to perform comprehensive analysis based on the kinematic equation of the McPherson suspension as a whole, the coordinate equation of the dynamic coordinates of the key coordinate points on the McPherson suspension plane motion diagram when they move, and the equation of the change of the stiffness coefficient and the damping coefficient of the elastic element during the movement, and use the Lagrangian method to construct a suspension dynamics model.

[0125] A modeling storage medium based on a McPherson suspension, the storage medium is used to store a computer program, and the computer program implements the above-mentioned modeling method when executed by a processor.

[0126] Compared with the prior art, the present invention establishes a detailed nonlinear dynamic model and combines the Lagrangian method with the kinematic characteristics of the suspension system to fully capture the dynamic changes and energy distribution of the suspension system. Compared with the 2DOF model in the prior art, it can more accurately describe the response characteristics of the suspension system under various complex working conditions, and the model is more accurate and practical, and consumes less resources and costs. It can provide a more economical and rapid theoretical basis for the design and performance analysis of the suspension, allowing engineers to more effectively optimize the suspension design and develop control strategies, so that the vehicle can maintain excellent performance under different driving conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0127] Figure 1 It is a schematic diagram of the overall method flow of the present invention;

[0128] Figure 2 It is a two-dimensional model diagram of the present invention;

[0129] Figure 3 is a planar motion diagram of the suspension in the present invention;

[0130] Figure 4 is a schematic diagram of an elastic element;

[0131] Figure 5 It is the curve diagram of Class B road surface excitation;

[0132] Figure 6 is a curve diagram showing the change of elastic force of the elastic element with piston displacement;

[0133] Figure 7 is a curve diagram showing the change of the stiffness coefficient of the elastic element with the piston displacement;

[0134] Figure 8 is a curve diagram showing the change of damping force of the elastic element with piston speed;

[0135] Fig. 9 is a curve diagram showing the change of damping coefficient of elastic element with piston speed;

[0136] Fig.10 is the response diagram of the suspension sprung mass displacement under road excitation;

[0137] Fig.11 is the response diagram of the suspension sprung mass acceleration under road excitation;

[0138] In the figure: 1. frame; 2. control arm; 3. elastic element; 4. wheel. DETAILED DESCRIPTION

[0139] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0140] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0141] Example:

[0142] See also Figures 1 to 11 , the present invention provides a technical solution:

[0143] A modeling method for a MacPherson suspension, the specific steps comprising:

[0144] S1: Draw the two-dimensional diagram and planar motion diagram based on the McPherson suspension, and make relevant simplified assumptions and definitions.

[0145] The relevant simplified assumptions are:

[0146] The sprung mass has only vertical motion, all suspension system components except the wheels are rigid, and the mass of the control arms and struts can be ignored;

[0147] The relevant simplified definitions include:

[0148] The sprung mass displacement is Z S , the sprung mass speed is The sprung mass acceleration is The displacement of the unsprung mass is Z U , the unsprung mass velocity is Unsprung mass acceleration The road disturbance is Z r , the road disturbance speed is The key coordinate points of the suspension are calibrated by letters O, A, B, C, D, and E. O is the origin of the global reference system, and the X and Y axes of the global reference system represent the horizontal and vertical directions respectively. The BD segment is the elastic element, and L 03 is the sum of the initial lengths of the elastic element and the support, L 3 is the sum of the real-time lengths of the elastic element and the support during the movement, L 3 -L 03 is the change of the elastic element, OA is the control arm, L 1 is the length of the control arm, θ 0 is the angle between the control arm and the Y axis in the initial state, θ is the angle the control arm rotates during the movement, C is the wheel center, is the angle between the wheel axis and the vertical direction, L 2 is the length of line segment OE, the state of the suspension can be expressed by two generalized coordinates corresponding to the degrees of freedom of the system (Z S and Z U ) is used to represent the initial equilibrium state; the dotted line represents the position of the initial equilibrium state; the elastic elements include hydro-pneumatic springs, air springs, and coil springs; the correlation coefficients include the displacement of key coordinate points, the velocity of key coordinate points, and the acceleration of key coordinate points; the unknown quantities in the equation include the displacement of sprung mass, the displacement of unsprung mass, the velocity of sprung mass, the velocity of unsprung mass, the acceleration of sprung mass, and the acceleration of unsprung mass.

[0149] In this step, the purpose of making definitions and assumptions is to consider the following aspects: First, it can simplify the complexity of the model. By assuming that the sprung mass only has vertical motion and other suspension system components are considered rigid, the complexity of the model can be effectively reduced, making the model easier to handle during analysis and calculation, and focusing on key dynamic behaviors; second, it can clarify the system parameters. By introducing the definitions of various key coordinate points and parameters (such as the displacement, velocity, acceleration, etc. of the sprung mass), a clear foundation is laid for subsequent mathematical modeling and simulation analysis. This clear definition can avoid confusion in the modeling process and ensure the accuracy of the modeling; third, it can enhance understanding and communication. By establishing two-dimensional graphs and planar motion graphs, a visual model structure can be provided, allowing engineers and researchers to more intuitively understand the geometric structure and motion characteristics of the suspension system, which helps to enhance communication and collaboration between teams.

[0150] Therefore, this step can not only reduce the number of variables and equations that need to be considered, thereby improving modeling efficiency, but also make it easier to perform parameter optimization and sensitivity analysis, identify key parameters that affect system performance, and then more effectively optimize the design of the suspension system, making subsequent mathematical models and simulation results more reliable.

[0151] S2: Use the displacement matrix method and the first-order Taylor expansion formula to perform kinematic analysis on the system based on the geometric relationships in the planar motion diagram.

[0152] In step S2, the logic of kinematic analysis of the system is:

[0153] S21: The displacement of the wheel on the plane is regarded as rotation and translation, and the kinematic characteristics of the plane motion diagram are analyzed using the displacement matrix method, where the displacement matrix D wheel It is expressed as:

[0154]

[0155] where Y C and Z C is the instantaneous coordinate of the wheel center C, Y C0 and Z C0 Respectively represent Y C and Z C The initial equilibrium value, a 11 =a 22 =cosφ, Where φ is the deflection angle of the wheel around the X-axis, and cosφ≈1, sinφ≈φ;

[0156] In the initial equilibrium state, the key coordinate points of the suspension are located at points O, A, B, C, D, and E respectively. The instantaneous coordinates of points A, B, and D are calculated using the displacement matrix and calibrated as (Y A ,Z A )、(Y B ,Z B )、(Y D ,Z D ), and the following equation is obtained:

[0157]

[0158] Where (Y A0 ,Z A0 )、(Y B0 ,Z B0 )、(Y D0 ,Z D0 ) represent the initial equilibrium coordinates of points A, B, and D respectively;

[0159] S22: Continue to perform kinematic analysis on the system and obtain the following equation:

[0160]

[0161] Where: a=Y B0 -Y C0 ,b=z B0 -Z C0 ,c=Y D0 -Y C0 ,d=Z D0 -Z C0 ,e=Y A0 -Y C0 ,f=Z A0 -Z C0 ;

[0162] S23: Perform kinematic analysis on the control arm and obtain the following equation:

[0163] Y A =L 1 (cosθcosθ 0 -sinθsinθ 0 )

[0164] Z A =L 1 (sinθcosθ 0 +cosθsinθ 0 )+Z S

[0165] g=L 1 sinθ 0

[0166] h=-L 1 cosθ 0

[0167] S24: Simplify the equation in step S23 to obtain the following equation:

[0168] Y A +gθ=-h

[0169] Y A +gθ=-h

[0170] S25: Since the control arm is a rigid component, the following equation is obtained:

[0171] (Y A -Y O ) 2 +(Z A -Z O ) 2 =L 1 2 =n

[0172] S26: Reconstruct function F 1 and function F 2 , let F 1 =(Y A -Y O ) 2 , F 2 =(Z A -Z O ) 2 , respectively for the function F 1 and function F 2 Perform a first-order Taylor expansion and linearize to obtain the following equation:

[0173] F 1 =(Y A0 -Y O0 ) 2 +2Y A0 (Y A -Y A0 )

[0174] F 2 =(Z A0 -Z O0 ) 2 +2(Z A0 -Z S )(Z A -Z A0 )-2Z A Z S

[0175] S27: Substitute the equation in step S26 into the equation in step S25 to obtain the following equation:

[0176] Y A0 Y A +(Z A0 -2Z S )Z A +Z A0 Z S =n.

[0177] In this step, by considering wheel displacement as a combination of rotation and translation, the displacement matrix method can accurately describe the motion characteristics of the key coordinate points of the wheel and suspension system, which can help engineers and researchers understand the behavior of the suspension system under different working conditions. By performing a first-order Taylor expansion on the nonlinear function, the complex nonlinear motion equations are converted into linear forms, making analysis and calculation easier and helping to simplify the subsequent solution of the dynamic equations.

[0178] Therefore, this step not only simplifies the calculation process, allowing complex kinematic problems to be quickly solved on the computer, thus shortening the design and verification cycle, but also provides key input parameters for subsequent dynamic modeling, ensuring the accuracy of the dynamic equations.

[0179] S3: Define the dynamic coordinates of the key coordinate points on the plane motion diagram.

[0180] In step S3, the logic of defining the dynamic coordinates of the key coordinate points on the plane motion graph is:

[0181] Steps S22, S24, and S27 define a set of equations with 11 unknown variables, using the sprung mass displacement Z S and the unsprung mass displacement Z U By linearizing it and solving the equation group, we can obtain the kinematic equations of the key variables of the suspension, as shown below:

[0182]

[0183] where a′=gY A0 +hZ A0 , b′=-2h, S=a′+b′Z S ;

[0184] Y C Simplifying, we get:

[0185]

[0186] in

[0187] f′=2g;

[0188] Take the first-order derivative of the Y-axis coordinate of the wheel center point C to get its lateral velocity Then take the second-order derivative to get its lateral acceleration Respectively expressed as:

[0189]

[0190] where j′=a′e′-d′b′, l′=a′ 2 f′-b′j′,

[0191] Define the following relationship:

[0192] h′=hn+(h 2 +g 2 )Y A0 ,i′=-hZ A0 +gY A0

[0193] The wheel deflection angle Simplified to:

[0194]

[0195] Deflection angle of the wheel Calculate the derivative twice in succession to get the angular velocity and angular acceleration

[0196]

[0197] The deflection displacement of the wheel caused by the movement δY tl The formula is as follows:

[0198] δY tl =Y C -Y C0 -φR

[0199] Y C and Substitute the simplified equation into the deflection displacement δY tl And simplify it in the formula to get the following equation:

[0200]

[0201] in

[0202] Then, the partial derivative of the wheel deflection displacement with respect to the sprung mass displacement and the unsprung mass displacement is obtained:

[0203]

[0204] where m′=a′u′-b′t′.

[0205] In this step, a set of equations with 11 unknown variables is constructed and solved, covering multiple key dynamic variables of the suspension system. This systematic solution method ensures a comprehensive understanding of the kinematic characteristics of the entire suspension system, and uses the linear representation of sprung mass displacement and unsprung mass displacement to transform complex nonlinear problems into linear problems under certain conditions, which significantly reduces the computational complexity and improves the solution efficiency.

[0206] Therefore, this step quickly obtains the key kinematic equations of the suspension system through linearization and algebraic solution, which undoubtedly greatly improves the analysis efficiency in engineering practice and facilitates rapid iteration and optimization of design. At the same time, the accurately calculated changes in speed, acceleration, and wheel deflection angle provide an accurate basis for predicting the dynamic response of the suspension system under different road conditions. The obtained accurate dynamic equations also provide a scientific basis for the development and verification of active suspension control strategies, helping to improve the comfort and safety of the vehicle.

[0207] S4: Draw a schematic diagram of the elastic element and define the changes in the stiffness coefficient and damping coefficient of the elastic element during movement.

[0208] In step S4, the logic for defining the change of the stiffness coefficient and the damping coefficient of the elastic element during the movement is:

[0209] The elastic element consists of a piston rod and piston assembly, a one-way valve, a damping hole, and a cylinder. 1 is the pressure of the working chamber of the elastic element, V 1 is the gas volume of the working chamber of the elastic element, A 1 is the cross-sectional area of ​​the inner cavity of the elastic element cylinder, P 2 is the annular cavity pressure, A 2 The cross-sectional area of ​​the annular cavity, x is the working stroke of the elastic element, where the working cavity of the elastic element is cavity I, and the annular cavity of the elastic element is cavity II.

[0210] During the working stroke of the elastic element, the piston rod is subjected to balanced force, and the equation for its output force F is:

[0211] F=P 1 A 1 -P 2 A 2

[0212] In equilibrium state, the state equation of the gas in the elastic element is:

[0213]

[0214] Where r is the gas polytropic index; V10 , P 10 are the gas volume and pressure in the initial state of the working chamber of the elastic element, respectively;

[0215] Working chamber gas volume V 1 The relationship between the cylinder displacement x and the piston displacement x is:

[0216] V 1 =V 10 -(A 1 -A 2 )x

[0217] Solve the above equations to get the elastic force F k The expression equation of (x) is:

[0218]

[0219] Elastic force F k (x) Take the derivative and get the stiffness K of the elastic element s for:

[0220]

[0221] When solving the static stiffness of the elastic element, r is taken as 1, and when solving the dynamic stiffness of the elastic element, r is taken as 1.73;

[0222] The pressure difference ΔP between the working chamber and the annular chamber is:

[0223] ΔP=P 1 -P 2

[0224] The equation for the oil flow Q flowing through the damping orifice and the one-way valve is:

[0225]

[0226] Where C z , C d is the flow coefficient, A z , A d is the effective flow area, z is the relevant parameter of the damping hole, d is the relevant parameter of the one-way valve, and ρ is the density of the hydraulic oil;

[0227] During the operation of the elastic element, the relationship between the oil flow rate flowing in the two chambers and the relative speed between the piston rods is:

[0228]

[0229] The equation between the combined output force, pressure difference, oil flow rate, oil flow rate and piston rod is:

[0230]

[0231] In the formula represents the damping force generated by the suspension orifice, and:

[0232]

[0233] right The movement speed of the elastic element Derivative, get the damping coefficient B of the elastic element S , the calculation formula is:

[0234]

[0235] In the formula is a direction function. When the compression stroke is positive, the movement speed of the elastic element The function value is 1; when the compression stroke is negative, the movement speed of the elastic element The function value is -1;

[0236] Since the elastic element is in the geometric structure of the suspension, the following equation is obtained:

[0237] x=δl=L 3 -L 03 .

[0238] In this step, the functions and interactions of the various components of the elastic element are clarified by describing and modeling the structure and working principle of the elastic element in detail, which helps to deeply understand how the element affects the performance of the suspension system in the dynamic process. By analyzing the force balance of the piston rod, the gas state equation and flow equation are used to accurately describe the output force, stiffness and damping characteristics of the elastic element. This precise analysis can help engineers better design and adjust suspension parameters to meet specific performance requirements. At the same time, distinguishing between static stiffness and dynamic stiffness, and considering the pressure difference and flow changes in the dynamic process, the model can more realistically reflect the behavior of the elastic element under different dynamic conditions.

[0239] The specific parameters of the suspension can be found in Table 1:

[0240] Table 1 Main system parameters of single air chamber suspension

[0241]

[0242] Therefore, this step can more accurately predict the performance of the suspension system under actual working conditions by quantitatively analyzing the dynamic changes of stiffness and damping coefficients, thereby improving the comfort and handling of the vehicle. The analysis results also provide direct guidance on how to optimize the parameters of elastic elements. By adjusting parameters such as gas volume, pressure, and flow coefficient, the suspension performance can be optimized to meet different vehicle requirements.

[0243] S5: Establish a nonlinear model, and through the kinematic analysis of steps S2 to S4, obtain the relationship between the correlation coefficients in the model and the unknown quantities in the equation, and construct a suspension dynamics model through the Lagrangian method.

[0244] In step S5, the logic of establishing the nonlinear model is:

[0245] The Lagrangian method is used to establish the vehicle dynamics equation, where the expressions of the suspension's kinetic energy T, potential energy V, and dissipated energy D are as follows:

[0246]

[0247] Where m S and m U are the chassis and wheel masses of the vehicle, I C represents the wheel inertia around the X axis, K S is the stiffness of the elastic element, K t and K tl They represent the vertical stiffness and lateral stiffness of the wheel, R is the effective radius of the wheel, and B S and B t They represent the damping coefficients of the suspension and wheels respectively, and δl is the working stroke of the elastic element;

[0248] Applying the law of cosines to the triangle OAE yields:

[0249] 2L 1 L 2 cosγ 0 =(L 1 ) 2 +(L 2 ) 2 -(L 03 ) 2

[0250] 2L 1 L 2 cos(γ 0 +θ)=(L 1 ) 2 +(L 2 ) 2 -(L 3 ) 2

[0251] The angle θ of the control arm rotation is small, so cosθ≈1, sinθ≈θ;

[0252] Combining the above equation with the law of cosines, we get:

[0253] (L 3 ) 2 =(L 03) 2 +kθ

[0254] k=-2L 1 L 2 sinγ 0

[0255] The working stroke of the elastic element is expressed as:

[0256]

[0257] Let B = (L 03 ) 2 + kθ, we get:

[0258]

[0259] δZ t =Z U -Z r

[0260] Applying the Lagrangian dynamics equation, we get:

[0261]

[0262] Combined with the wheel deflection displacement, the partial derivative equations of the sprung mass displacement and the unsprung mass displacement, the dissipated energy equation, δZ t The expression equation of , and the Lagrangian dynamics equation of the above formula, get the final expression:

[0263]

[0264] The above two equations are the final mathematical expressions of the nonlinear model, completing the establishment of the nonlinear model.

[0265] In this step, the kinematic analysis results, stiffness coefficients, damping coefficients and other key parameters obtained in steps S2 to S4 are systematically integrated into a unified dynamic model to ensure the consistency and integrity of the model. The nonlinear model established by the Lagrangian method can accurately capture the nonlinear dynamic characteristics of the suspension system in actual work, such as nonlinear deformation of elastic elements, damping changes, etc., and this nonlinear model can more accurately reflect the dynamic behavior of the suspension system under actual working conditions, and provides higher accuracy and reliability compared to linear models. Therefore, it also helps to better adjust the performance of the suspension system, allowing engineers to more effectively optimize the suspension design and develop control strategies, so that the vehicle can maintain excellent performance under different driving conditions.

[0266] The present invention also provides a modeling system based on the McPherson suspension, which is used to execute the above modeling method, and comprises: an image drawing module, a first analysis module, a coordinate definition module, a second analysis module, and a comprehensive processing module.

[0267] The image drawing module is used to draw a two-dimensional diagram and a plane motion diagram of the McPherson suspension, as well as a schematic diagram of the elastic element, and to add characters to the two-dimensional diagram and the plane motion diagram of the McPherson suspension, as well as the schematic diagram of the elastic element for calibration;

[0268] The first analysis module is used to perform kinematic analysis on the entire McPherson suspension according to the two-dimensional diagram and the plane kinematic diagram of the McPherson suspension, and obtain the corresponding kinematic equation;

[0269] The coordinate definition module is used to define and calculate the dynamic coordinates of the key coordinate points on the plane motion diagram of the McPherson suspension according to the kinematic equations obtained in the data analysis module, and obtain the corresponding coordinate equations;

[0270] The second analysis module is used to define and calculate the changes of the stiffness coefficient and the damping coefficient of the elastic element during the movement according to the elastic element schematic diagram, and obtain the corresponding change equation;

[0271] The comprehensive processing module is used to conduct a comprehensive analysis based on the kinematic equation of the McPherson suspension as a whole, the coordinate equation of the dynamic coordinates of the key coordinate points on the McPherson suspension plane motion diagram, and the equation for the change of the stiffness coefficient and damping coefficient of the elastic element during the movement, and construct the suspension dynamics model using the Lagrangian method.

[0272] The present invention also provides a modeling storage medium based on the McPherson suspension, which is used to store a computer program. When the computer program is executed by a processor, the above-mentioned modeling method is implemented.

[0273] In the present invention, the key coordinate points and parameters of the suspension can be referred to as shown in Table 2:

[0274] Table 2 Main hard points and parameters of suspension

[0275]

[0276] In the present invention, a 1 / 4 car model is used to study the car performance, and the characteristic curve of the model established by the utility model is plotted using MATLAB software, thereby providing a basis for the study of the car's ride comfort and handling stability. However, the nonlinear model of the McPherson suspension finally constructed is not limited to the 1 / 4 car model, but is also applicable to the whole car model, 1 / 2 car model and other models. The specific curve is as follows:

[0277] Curve 1: See Figure 5Class B road surface is a typical road grade defined according to the standards of the International Organization for Standardization (ISO). It is characterized by medium roughness and is suitable for general urban roads or rural roads. This roughness has a significant impact on the vibration performance of the vehicle and is an important factor that must be considered when studying suspension kinematics.

[0278] Curve 2: See Figure 6 , Figure 6 It is used to reflect the change of elastic force of elastic elements with road excitation. The elastic force of elastic elements can absorb and buffer the vibration and impact caused by uneven road surface, thereby reducing the acceleration and pitch acceleration of the vehicle body and improving ride comfort. In heavy vehicles, due to the large load difference, the nonlinear working characteristics of elastic elements can better meet the smoothness requirements under different working conditions.

[0279] Curve 3: See Figure 7 , Figure 7 It is used to reflect the change of the stiffness coefficient of the elastic element with the road excitation. The elastic element has the characteristics of nonlinear gradual stiffness. When driving on good roads, the suspension dynamic deflection is small, and the stiffness of the elastic element is kept at the small stiffness expected by the design, making the vehicle drive more smoothly. When driving on bad roads, the suspension dynamic deflection is large, and the suspension stiffness will also increase, which can absorb more impact energy and prevent collision with the limit block, playing a good buffering role. This nonlinear stiffness change can significantly improve the driving smoothness of the vehicle under bad road conditions.

[0280] Curve 4: Please refer to Figure 8 , Figure 8 The curve used to reflect the change of the damping force of the elastic element with the speed of the piston rod movement. There is a difference in the damping force of the elastic element's restoring stroke (piston rod moving upward) and compression stroke (piston rod moving downward), and the damping force of the restoring stroke is usually greater than the damping force of the compression stroke. This two-way damping difference helps to better control the pitch and roll movement of the vehicle during driving, and improve the stability and safety of the vehicle.

[0281] Curve 5: Please refer to Fig. 9 , Fig. 9 The curve used to reflect the change of the damping coefficient of the elastic element with the movement speed of the piston rod is that when the road excitation fluctuation is small, the damping coefficient is small, so that the elastic element has a moderate attenuation effect on the vehicle vibration, which is neither too hard nor too soft, thus ensuring the smoothness of the vehicle's ride. When the road excitation fluctuation is large, the damping coefficient increases, and the elastic element can absorb more impact energy to prevent impact on the limit block, further improving the vehicle's driving stability and ride comfort.

[0282] Curve 6: See Fig.10 , Fig.10It is used to reflect the response of the system to the sprung mass displacement when the road input is Class B road excitation. The sprung mass displacement is one of the important evaluation indicators of vehicle ride comfort. The study of peak time, overshoot and response time in random excitation of vehicles has important guiding significance for suspension design.

[0283] Curve 7: Please refer to Fig.11 , Fig.11 The frequency response function used to reflect the acceleration of the sprung mass of the system. The discomfort of passengers in the car is proportional to the acceleration of the sprung mass during driving. Therefore, taking into account the overall performance parameters of the vehicle, the acceleration of the sprung mass should be as small as possible.

[0284] In summary, the present invention establishes a detailed nonlinear dynamic model and combines the Lagrangian method with the kinematic characteristics of the suspension system to comprehensively capture the dynamic changes and energy distribution of the suspension system. Compared with the 2DOF model in the prior art, it can more accurately describe the response characteristics of the suspension system under various complex working conditions, and the model is more accurate and practical, and consumes less resources and costs. It can provide a more economical and rapid theoretical basis for the design and performance analysis of the suspension, allowing engineers to more effectively optimize the suspension design and develop control strategies, so that the vehicle can maintain excellent performance under different driving conditions.

[0285] The above formulas are all dimensionless and numerical calculations. The formula is a formula for the most recent real situation obtained by collecting a large amount of data and performing software simulation. The preset parameters in the formula are set by technicians in this field according to actual conditions.

[0286] The above embodiments may be implemented in whole or in part by software, hardware, firmware or any other combination thereof. When implemented by software, the above embodiments may be implemented in whole or in part in the form of a computer program product. Those skilled in the art may appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein may be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed by hardware or software methods depends on the specific application and design constraints of the technical solution.

[0287] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, and may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0288] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application.

Claims

1. A modeling method for a McPherson suspension, characterized in that: The specific steps include: S1: Draw the two-dimensional model diagram and plane motion diagram of the McPherson suspension, make simplified assumptions about the motion trajectory and physical properties of the McPherson suspension, and simplify the definitions of the various positions in the plane motion diagram corresponding to the McPherson suspension; S2: Using the displacement matrix method and the first-order Taylor expansion formula, the kinematic analysis of the McPherson suspension is performed based on the geometric relationship in the plane kinematic diagram, the displacement matrix of the wheel displacement process is obtained, and the kinematic equation of the wheel displacement is generated based on the displacement matrix; S3: define the key coordinate points on the plane motion diagram and the dynamic coordinates of the key coordinate points, linearly represent and solve the kinematic equation of wheel displacement, and construct the kinematic equation of wheel deflection displacement based on the solution results; S4: Draw a schematic diagram of the elastic element, define the changes of the stiffness coefficient and the damping coefficient of the elastic element during movement, and construct the change equations corresponding to the stiffness coefficient and the damping coefficient respectively; S5: Establish a nonlinear model, jointly solve the equations in steps S2 to S4, obtain the relationship between the correlation coefficients in the model and the unknown quantities in the equations, and construct a suspension dynamics model through the Lagrangian method.

2. The modeling method of a McPherson suspension according to claim 1, characterized in that: The correlation coefficients include displacement, velocity, and acceleration of key coordinate points; the unknown quantities in the equation include sprung mass displacement, unsprung mass displacement, sprung mass velocity, unsprung mass velocity, sprung mass acceleration, and unsprung mass acceleration.

3. A modeling method for a McPherson suspension according to claim 1, characterized in that: In step S1, the simplified assumptions made for the motion trajectory and physical properties of the McPherson suspension are: The sprung mass only moves vertically, all suspension system components except the wheels are rigid components, and the mass of the control arms and struts is negligible; The simplified definitions of the various positions in the planar kinematic diagram corresponding to the MacPherson suspension include: The sprung mass displacement is Z S , the sprung mass speed is The sprung mass acceleration is The displacement of the unsprung mass is Z U , the unsprung mass velocity is Unsprung mass acceleration The road disturbance displacement is Z r , the road disturbance speed is The key coordinate points of the suspension include the reference origin, the end point of the control arm, the lower end point of the elastic element, the center of the wheel, the upper end point of the elastic element, and the connection point between the frame and the elastic element, which are calibrated by the letters O, A, B, C, D, and E respectively; the X and Y axes of the global reference system represent the horizontal and vertical directions respectively; the BD segment is the elastic element, and the L segment is the elastic element. 03 is the sum of the initial lengths of the elastic element and the support, L3 is the sum of the real-time lengths of the elastic element and the support during the movement, L3-L 03 is the change of the elastic element, OA is the control arm, L1 is the length of the control arm, θ0 is the angle between the control arm and the Y axis in the initial state, θ is the angle the control arm rotates during the movement, is the angle between the axis of the wheel and the vertical direction, L2 is the length of the line segment OE, and the state of the suspension is represented by two generalized coordinates corresponding to the degrees of freedom of the system.

4. The modeling method of a McPherson suspension according to claim 3, characterized in that: In step S2, the logic of kinematic analysis of the system is: S21: The displacement of the wheel on the plane is regarded as rotation and translation, and the kinematic characteristics of the plane motion diagram are analyzed using the displacement matrix method, where the displacement matrix D wheel It is expressed as: where Y C and Z C is the instantaneous coordinate of the wheel center C, Y C0 and Z C0 Respectively represent Y C and Z C The initial equilibrium value, a 11 =a 22 =cosφ, Where φ is the angle of deflection of the wheel around the X-axis, and cosφ≈1, sinφ≈φ; In the initial equilibrium state, the key coordinate points of the suspension are located at points O, A, B, C, D, and E respectively. The instantaneous coordinates of points A, B, and D are calculated using the displacement matrix and calibrated as (Y A ,Z A )、(Y B ,Z B )、(Y D ,Z D ), and the following equation is obtained: Where (Y A0 ,Z A0 )、(Y B0 ,Z B0 )、(Y D0 ,Z D0 ) represent the initial equilibrium coordinates of points A, B, and D respectively; S22: Continue to perform kinematic analysis on the system and obtain the following equation: S23: Perform kinematic analysis on the control arm and obtain the following equation: AND A =L1(cosθcosθ0-sinθsinθ0) Z A =L1(sinθcosθ0+cosθsinθ0)+Z S g=L1sinθ0 h=-L1cosθ0 S24: Simplify the equation in step S23 to obtain the following equation: Y A +gθ=-h S25: Since the control arm is a rigid component, the following equation is obtained: (AND A -AND O ) 2 +(Z A -Z O ) 2 =L1 2 S26: Reconstruct function F1 and function F2, let F1 = (Y A -Y O ) 2 , F2=(Z A -Z O ) 2 , perform first-order Taylor expansion on function F1 and function F2 respectively, and linearize them to obtain the following equations: F1=(Y A0 -AND O0 ) 2 +2Y A0 (AND A -AND A0 ) F2=(Z A0 -Z O0 ) 2 +2(Z A0 -Z S )(From A -Z A0 )-2Z A From S S27: Substitute the equation in step S26 into the equation in step S25 to obtain the following equation: Y A0 Y A +(Z A0 -2Z S )Z A +Z A0 Z S =L1 2 。 5. The modeling method of a McPherson suspension according to claim 4, characterized in that: In step S3, the logic of defining the dynamic coordinates of the key coordinate points on the plane motion graph is: Steps S22, S24, and S27 define a set of equations with 11 unknown variables, using the sprung mass displacement Z S and the unsprung mass displacement Z U By linearizing it and solving the equation group, we can obtain the kinematic equations of the key variables of the suspension, as shown below: where a′=gY A0 +hZ A0 , b′=-2h, S=a′+b′Z S ; Y C Simplifying, we get: in f′=2g Take the first-order derivative of the Y-axis coordinate of the wheel center point C to get its lateral velocity Then take the second-order derivative to get its lateral acceleration Respectively expressed as: where j′=a′e′-d′b′, l′=a′ 2 f′-b′j′; Define the following relationship: h′=hn+(h 2 +g 2 )Y A0 ,i′=-hZ A0 +gY A0 The wheel deflection angle Simplified to: Deflection angle of the wheel Calculate the derivative twice in succession to get the angular velocity and angular acceleration The deflection displacement of the wheel caused by the movement δY tl The formula is as follows: δY tl =Y C -Y C0 -φR Y C and Substitute the simplified equation into the deflection displacement δY tl And simplify it in the formula to get the following equation: in Then, the partial derivative of the wheel deflection displacement with respect to the sprung mass displacement and the unsprung mass displacement is obtained: where m′=a′u′-b′t′.

6. The modeling method of a McPherson suspension according to claim 5, characterized in that: In step S4, the logic for defining the change of the stiffness coefficient and the damping coefficient of the elastic element during the movement is: The elastic element is composed of a piston rod and piston assembly, a one-way valve, a damping hole, and a cylinder. P1 is the pressure of the working chamber of the elastic element, V1 is the gas volume of the working chamber of the elastic element, A1 is the cross-sectional area of ​​the inner chamber of the cylinder of the elastic element, P2 is the annular chamber pressure, A2 is the cross-sectional area of ​​the annular chamber, and x is the working stroke of the elastic element. During the working stroke of the elastic element, the piston rod is subjected to balanced force, and the equation for its output force F is: F=P1A1-P2A2 In equilibrium state, the state equation of the gas in the elastic element is: Where r is the gas polyvariability index; V 10 , P 10 are the gas volume and pressure in the initial state of the working chamber of the elastic element, respectively; The relationship between the working chamber gas volume V1 and the cylinder displacement x relative to the piston is: V1=V 10 -(A1-A2)x Solve the above equations to get the elastic force F k The expression equation of (x) is: Elastic force F k (x) Take the derivative and get the stiffness coefficient K of the elastic element s for: When solving the static stiffness of the elastic element, r is taken as 1, and when solving the dynamic stiffness of the elastic element, r is taken as 1.73; The pressure difference ΔP between the working chamber and the annular chamber is: ΔP=P1-P2 The equation for the oil flow Q flowing through the damping orifice and the one-way valve is: Where C z , C d is the flow coefficient, A z , A d is the effective flow area, z is the relevant parameter of the damping hole, d is the relevant parameter of the one-way valve, and ρ is the density of the hydraulic oil; During the operation of the elastic element, the relationship between the oil flow rate flowing in the two chambers and the relative speed between the piston rods is: The equation between the combined output force, pressure difference, oil flow rate, oil flow rate and piston rod is: In the formula represents the damping force generated by the suspension orifice, and: right The movement speed of the elastic element Derivative, get the damping coefficient B of the elastic element S , the calculation formula is: In the formula is a direction function. When the compression stroke is positive, the movement speed of the elastic element The function value is 1; when the compression stroke is negative, the movement speed of the elastic element The function value is -1; Since the elastic element is in the geometric structure of the suspension, the following equation is obtained: x=δl=L3-L 03 。 7. The modeling method of a McPherson suspension according to claim 6, characterized in that: In step S5, the logic of establishing the nonlinear model is: The Lagrangian method is used to establish the vehicle dynamics equation, where the expressions of the suspension's kinetic energy T, potential energy V, and dissipated energy D are as follows: Where m S and m U are the chassis and wheel masses of the vehicle, I C represents the wheel inertia around the X axis, K S is the stiffness of the elastic element, K t and K tl They represent the vertical stiffness and lateral stiffness of the wheel, R is the effective radius of the wheel, and B S and B t They represent the damping coefficients of the suspension and wheels respectively, and δl is the working stroke of the elastic element; Applying the law of cosines to triangle OAE yields: 2L1L2cosγ0=(L1) 2 +(L2) 2 -(L 03 ) 2 <h2 style=";text-align:left;direction:ltr">2L1L2cos(γ0+θ)=(L1)<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> +(L2)<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> -(L3)<h2 style=";text-align:left;direction:ltr"> 2 The angle θ of the control arm rotation is small, so cosθ≈1, sinθ≈θ; Combining the above equation with the law of cosines, we get: (L3) 2 =(L 03 ) 2 +kθ k=-2L1L2 sinγ0 The working stroke of the elastic element is expressed as: Let B = (L 03 ) 2 + kθ, we get: δZ t =Z U -Z r Applying the Lagrangian dynamics equation, we get: Combined with the wheel deflection displacement, the partial derivative equations of the sprung mass displacement and the unsprung mass displacement, the dissipated energy equation, δZ t The expression equation of , and the Lagrangian dynamics equation of the above formula, get the final expression: The above two equations are the final mathematical expressions of the nonlinear model, completing the establishment of the nonlinear model.

8. The modeling method of a McPherson suspension according to claim 1, characterized in that: The elastic element includes an oil-gas spring, an air spring, and a coil spring.

9. A modeling system based on MacPherson suspension, characterized in that: The modeling system is used to execute the modeling method according to any one of claims 1 to 8, comprising: An image drawing module, wherein the image drawing module is used to draw a two-dimensional image and a plane motion image of the McPherson suspension, as well as a schematic diagram of the elastic element, and to add characters to the two-dimensional image and the plane motion image of the McPherson suspension, as well as the schematic diagram of the elastic element for calibration; A first analysis module, wherein the first analysis module is used to perform kinematic analysis on the entire McPherson suspension according to a two-dimensional diagram and a planar kinematic diagram of the McPherson suspension, and obtain a corresponding kinematic equation; A coordinate definition module, which is used to define and calculate the dynamic coordinates of the key coordinate points on the plane motion diagram of the McPherson suspension according to the kinematic equations obtained in the data analysis module, and obtain the corresponding coordinate equations; A second analysis module, the second analysis module is used to define and calculate the changes of the stiffness coefficient and the damping coefficient of the elastic element during the movement according to the elastic element schematic diagram, and obtain the corresponding change equation; The comprehensive processing module is used to perform comprehensive analysis based on the kinematic equation of the McPherson suspension as a whole, the coordinate equation of the dynamic coordinates of the key coordinate points on the McPherson suspension plane motion diagram when they move, and the equation of the change of the stiffness coefficient and the damping coefficient of the elastic element during the movement, and use the Lagrangian method to construct a suspension dynamics model.

10. A modeling storage medium based on a McPherson suspension, characterized in that: The storage medium is used to store a computer program, and when the computer program is executed by a processor, the modeling method according to any one of claims 1 to 8 is implemented.

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