Method for calculating vibration isolation rate of vehicle body suspension system

Abstract

The invention discloses a vehicle body suspension system vibration isolation rate calculation method, and relates to the field of vehicle body suspension system optimization design, and the method comprises the following steps: obtaining a vehicle body suspension system three-dimensional model, vehicle body inertial parameters, vehicle body suspension system mechanical parameters, and a transverse stabilizer bar flexible body; creating a corresponding constraint relationship according to a motion rule among the components, so as to construct a rigid-flexible coupling model of the vehicle body suspension system; acceleration time domain signals of the frame side and the vehicle body side of the suspension system are obtained according to a real vehicle ride comfort test; converting the time domain signal into a frequency domain amplitude through fast Fourier transform, and calculating a simulation vibration isolation rate and a test vibration isolation rate of the suspension system according to a vibration isolation rate formula; according to the difference between the simulation vibration isolation rate and the test vibration isolation rate, rigidity and damping correction coefficients are introduced, and the accurate simulation vibration isolation rate is calculated through an iterative algorithm. According to the method, the vibration isolation rate calculation precision is improved, and the design optimization support is enhanced.

Description

Technical Field

[0001] The invention relates to the field of vehicle body suspension system optimization design, and in particular to a method for calculating the vibration isolation rate of a vehicle body suspension system. Background Art

[0002] As a key component of automobile vibration isolation, the body suspension system can effectively isolate the vibration transmitted from the road excitation to the frame, thereby improving the ride comfort and stability of the vehicle. As an important quantitative indicator of the vibration isolation performance of the suspension system, the vibration isolation rate can directly reflect the effect of the system in isolating vibration, and therefore becomes a key basis for evaluating the performance of the suspension system.

[0003] Under the current technical background, the calculation of the vibration isolation rate of the vehicle body suspension system usually relies on experimental testing. However, experimental testing has many limitations, such as high cost, long time consumption, and difficulty in timely feedback during the design stage. Therefore, the vibration isolation rate calculation method based on simulation has gradually become the focus of research. By establishing a rigid-flexible coupling model of the vehicle body suspension system, the vibration isolation performance of the suspension system can be predicted without relying on a large number of tests. However, since the suspension system contains multiple nonlinear elements (such as air springs, shock absorbers, bushings, etc.), there is often a certain error between the simulation results and the actual test results, which affects the accuracy of the simulation. Summary of the invention

[0004] In view of the defects existing in the prior art, the purpose of the present invention is to provide a method for calculating the vibration isolation rate of a vehicle body suspension system, thereby improving the calculation accuracy of the vibration isolation rate and enhancing the support for design optimization.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is: a method for calculating the vibration isolation rate of a vehicle body suspension system, comprising the following steps:

[0006] Step S1. Obtaining a three-dimensional model of a vehicle body suspension system, vehicle body inertia parameters, vehicle body suspension system mechanical parameters, and a lateral stabilizer bar flexible body; creating corresponding constraint relationships according to the motion laws between the various components, thereby constructing a rigid-flexible coupling model of the vehicle body suspension system;

[0007] Step S2. Acquire acceleration time domain signals of the frame side and the body side of the suspension system according to the actual vehicle ride comfort test;

[0008] Step S3. Convert the time domain signal into a frequency domain amplitude by fast Fourier transform, and calculate the simulation vibration isolation rate and the test vibration isolation rate of the suspension system according to the vibration isolation rate formula;

[0009] Step S4. According to the difference between the simulated vibration isolation rate and the experimental vibration isolation rate, stiffness and damping correction coefficients are introduced, and the accurate simulated vibration isolation rate is calculated through an iterative algorithm.

[0010] Based on the above technical solution, step S1 specifically includes:

[0011] Step S101. Establishing a three-dimensional model of the vehicle body suspension system: obtaining geometric parameters of the vehicle body suspension system through given design drawings, establishing part drawings of each component according to the geometric parameters in a three-dimensional modeling software, and then establishing an assembly three-dimensional model of the vehicle body suspension system according to the positional relationship;

[0012] Step S102. Test the inertia parameters of the vehicle body: Use the torsion pendulum method to measure the vehicle body mass m and the center of mass position O, and the moment of inertia J of the vehicle body around the X axis. xx , the moment of inertia around the Y axis J yy , the moment of inertia around the Z axis J zz , the inertia product of the vehicle body about the X-axis and Y-axis J xy , the inertia product J about the X-axis and Z-axis xz , the product of inertia J about the Y axis and the Z axis yz ;

[0013] Step S103. Test the mechanical parameters of the vehicle body suspension system: the vehicle body suspension system includes g suspensions, g=2-8, which are named suspension 1, suspension 2, ..., suspension g from front to back; the axial stiffness K of the air spring is measured by the elastic body test system i ,i=1,2,…,g;The damping coefficient C of the shock absorber is measured by using the shock absorber dynamometer i , i=1,2,…,g; the six-directional stiffness curves of various bushings are measured by the elastic body testing system;

[0014] Step S104. Flexible processing of the lateral stabilizer bar: meshing the three-dimensional digital model of the lateral stabilizer bar, assigning alloy steel material properties, constraining both ends of the stabilizer bar, and obtaining a data exchange file through modal comprehensive analysis.

[0015] On the basis of the above technical solution, in step S101, the geometric parameters include upper and lower brackets, a lateral stabilizer bar, an air spring and various bushings.

[0016] On the basis of the above technical solution, step S2 specifically includes:

[0017] Step S201. Sensor arrangement: a three-axis acceleration sensor is installed at each suspended frame end and body end, and the coordinate axis direction of the sensor local coordinate system is ensured to be parallel to the coordinate axis direction of the reference coordinate system; each acceleration sensor is connected to the vibration and noise test system through an independent channel;

[0018] Step S202. Testing the acceleration of each suspension on the frame side and the body side: using a random input driving test method to perform a real vehicle ride comfort test, collecting acceleration time domain signals of each suspension on the frame side and the body side during the test;

[0019] Step S203. Frame side acceleration signal processing: removing trend items and eliminating burrs from the collected frame side vibration acceleration signal.

[0020] On the basis of the above technical solution, in step S202, when conducting a real vehicle smoothness test, the vehicle is driven on a high-loop road at five operating speeds of 40km / h, 50km / h, 60km / h, 70km / h, and 80km / h. The test vehicle speed is monitored by a speedometer, maintaining a constant speed in the steady speed section, and passing the test section at a specified uniform speed.

[0021] Based on the above technical solution, in step S203, the trend item removal process is specifically performed using the following formula:

[0022]

[0023] Where: y detrended,i is the data after removing the trend term, y i is the original data, a0,a1,...,a n are the polynomial coefficients obtained by least squares fitting.

[0024] On the basis of the above technical solution, in step S203, the burr elimination process is specifically performed by using a five-point sliding average method, and the calculation formula of the five-point sliding average is:

[0025]

[0026] In the formula: x is the sampled data; y is the result after smoothing; m is the number of data points; 2N+1 is the average number of points; h is the weighted average factor.

[0027] Based on the above technical solution, step S3 specifically includes:

[0028] Step S301. Calculate the vibration isolation rate of the vehicle body suspension: The processed frame side vibration acceleration time domain signal Input the rigid-flexible coupling model of the vehicle body suspension, perform simulation, and obtain the time domain signal of the vehicle body side acceleration response. right Using fast Fourier transform, we can get the frequency domain amplitude Then according to the formula Obtain the simulated vibration isolation rate of each mount, where i = 1, 2, …, g;

[0029]

[0030] Where: X[k] is the kth frequency component in the frequency domain, representing the frequency domain amplitude, x[n] is the nth sampling point in the time domain, and N is the total number of sampling points of the signal;

[0031] Step S302: Process the data to obtain the test vibration isolation rate: The acceleration time domain signals of the frame side and the body side obtained by the test are After FFT, the amplitudes in the frequency domain are obtained. Where i=1,2,…,g, then according to the formula The experimental vibration isolation rate of each mount is obtained.

[0032] Based on the above technical solution, in step S4, the iterative algorithm calculation formula is as follows

[0033] K k =u k K i ,C k =v k C i ,i=0,1,2…,g (1)

[0034]

[0035]

[0036] In the above formulas, the subscript i=1, 2, ..., g represents the suspension number.

[0037] Based on the above technical solution, the iterative process specifically includes:

[0038] Step S401. Initial condition setting: Let the correction coefficient u k 、v k The initial value is 1;

[0039] Step S402. Calculation of suspension stiffness and damping coefficient: Calculate the modified suspension stiffness and damping coefficient according to formula (1);

[0040] Step S403. Calculation of simulated vibration isolation rate: After running the simulation and processing the data, the simulated vibration isolation rate of the suspension is obtained according to formula (2);

[0041] Step S404. Calculation of test vibration isolation rate: After processing the test data, calculate the test vibration isolation rate of the suspension according to formula (3);

[0042] Step S405. Convergence judgment: If the relative error between the simulated vibration isolation rate obtained in step 403 and the experimental vibration isolation rate obtained in step 404 is within the range of ±1%, the iteration ends; at this time, the simulated vibration isolation rate calculated in step 403 is the final result; otherwise, return to step 401, adjust the correction coefficient, and continue iteration.

[0043] The beneficial effects of the present invention are:

[0044] 1. Improve the calculation accuracy of the vibration isolation rate of the vehicle body suspension: By constructing a three-dimensional model of the vehicle body suspension system, the inertia parameters of the vehicle body, the mechanical parameters of the suspension, and the flexibility characteristics of the lateral stabilizer bar are integrated to ensure the accuracy of the model structure and mechanical properties. The stiffness and damping parameters are corrected using an iterative algorithm to make the simulated vibration isolation rate closer to the test value, thereby significantly improving the accuracy of the simulation results and providing a more reliable basis for the analysis of the system's vibration isolation performance.

[0045] 2. Enhanced support for design optimization: Accurate vibration isolation rate calculation provides a scientific guide for the design and optimization of the vehicle body suspension system, making it easier to achieve the vibration isolation performance design indicators. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 is a three-dimensional model diagram of the vehicle body suspension system in the present invention;

[0047] Figure 2 is a rigid-flexible coupling model diagram of the vehicle body suspension system in the present invention;

[0048] Figure 3 It is a comparison diagram of the X-direction acceleration time domain signals of the suspension 1 frame side and the vehicle body side under the 60km / h working condition in the present invention;

[0049] Figure 4 It is a comparison diagram of the Y-direction acceleration time domain signals of the suspension 1 frame side and the vehicle body side under the 60km / h working condition in the present invention;

[0050] Figure 5 It is a comparison diagram of the Z-direction acceleration time domain signals of the suspension 1 frame side and the vehicle body side under the 60km / h working condition in the present invention;

[0051] Figure 6 It is a comparison of the time domain signal of the Z-direction frame side acceleration of the suspension 1 before and after processing under the working condition of 60km / h in the present invention;

[0052] Figure 7 are the acceleration amplitudes and vibration isolation rates of the frame side and the vehicle body side of the mount 1 in the Z direction obtained by simulation under the working condition of 60 km / h in the present invention;

[0053] Figure 8 are the acceleration amplitudes and vibration isolation rates of the Z-axis frame side and vehicle body side of the mount 1 obtained by testing under the 60 km / h working condition in the present invention;

[0054] Fig. 9 is an iterative flow chart of calibrating the simulated vibration isolation rate in the present invention;

[0055] Fig.10 It is a comparison chart of the Z-direction simulated vibration isolation rate and the experimental vibration isolation rate of the suspension 1 iteratively obtained under the 60km / h working condition in the present invention. DETAILED DESCRIPTION

[0056] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions.

[0057] In the description of the present invention, it should be noted that directional words, such as the terms "center", "lateral (X)", "longitudinal (Y)", "vertical (Z)", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating directions and positional relationships are based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of narrating the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and cannot be understood as limiting the specific scope of protection of the present invention.

[0058] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features. Therefore, the definition of "first" and "second" features can explicitly or implicitly include one or more of the features. In the description of the present invention, "several" and "a number" mean two or more, unless otherwise clearly and specifically defined.

[0059] In the present invention, unless otherwise specified and limited, the terms "assemble", "connect", and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can also be a mechanical connection; it can be directly connected, or it can be connected through an intermediate medium, or the two elements can be internally connected. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0060] In the invention, unless otherwise specified and limited, a first feature being “above” or “below” a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being “above”, “below”, and “above” a second feature includes that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “above”, “below”, and “below” a second feature includes that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0061] The following is a further description of the specific embodiments of the present invention in conjunction with the drawings of the specification, so that the technical solution and its beneficial effects of the present invention are clearer and more explicit. The following description of the embodiments with reference to the drawings is exemplary and intended to explain the present invention, but cannot be understood as limiting the present invention.

[0062] An embodiment of the present invention provides a method for calculating a vibration isolation rate of a vehicle body suspension system, comprising:

[0063] (1) Establish a three-dimensional model of the vehicle body suspension system:

[0064] According to the CAD design drawings of the vehicle body suspension system, obtain the geometric parameters of each key component in the system, including the specific position, size and geometry of the upper and lower brackets, lateral stabilizer bar, air spring and various bushings; select the "Design" module in the 3D CAD modeling software, create basic points, lines, planes and geometric features based on these parameters, and establish part drawings for the key structures of the suspension system one by one; enter the Assembly module of the 3D CAD modeling software, create a new assembly file, put the created parts into the assembly, and define the assembly relationship and constraints between them. The completed 3D model of the vehicle body suspension system is as follows: Figure 1 As shown;

[0065] (2) Obtaining vehicle body inertia parameters:

[0066] The torsion pendulum test bench is used to measure the vehicle body mass m and the position of the vehicle body center of mass O. A fixed coordinate system O-XYZ is established with O as the origin. The X-axis is parallel to the longitudinal direction of the vehicle body, the positive direction points to the rear of the vehicle body, the Z-axis is vertically upward, and the Y-axis is determined according to the right-hand rule. After measuring the moment of inertia J of the vehicle body assembly around the X-axis, xx , the moment of inertia around the Y axis J yy , the moment of inertia around the Z axis J zz , the inertia product of the body assembly about the X-axis and Y-axis J xy , the inertia product J about the X-axis and Z-axis xz , the product of inertia J about the Y axis and the Z axis yz ; The parameters obtained in this example are as follows;

[0067] m=1440kg

[0068] O = [-188.7, 0.0, 1201.0]

[0069]

[0070] (3) Test the mechanical parameters of the vehicle body suspension system:

[0071] The vehicle body suspension system includes four suspensions (denoted as g = 4g), namely the left front, right front, left rear and right rear, respectively, named suspension 1, suspension 2, ..., suspension g; the axial stiffness K of the air spring is measured using the elastic body test system i (i=1,2,…,g); The damping coefficient C of the shock absorber is measured by using the shock absorber dynamometer i (i=1,2,…,g); the six-directional stiffness curves of various bushings were measured using the American MTS831 elastomer testing system.

[0072]

[0073] (4) Flexible treatment of the lateral stabilizer bar:

[0074] The three-dimensional digital model of the lateral stabilizer bar can be obtained from step 1, which is imported into professional meshing software for meshing, and the alloy steel material properties are given to constrain the two ends of the stabilizer bar. The data exchange file is obtained through modal comprehensive analysis and imported into the multi-body dynamics analysis software, and the two ends of the stabilizer bar are set to be fixedly connected to the swing arm;

[0075] (5) Establishing the vehicle body suspension system model:

[0076] Import the three-dimensional model of the vehicle body suspension system, the inertia parameters of the vehicle body, the mechanical parameters of the vehicle body suspension system, and the flexible body of the lateral stabilizer bar into the multi-body dynamics analysis software (such as UG NX-1.0); create a ball at the center of mass of the vehicle body to replace the vehicle body, and input the inertia parameters; create corresponding constraint relationships according to the movement laws between the components, such as adding elastic elements, setting fixed constraints, etc., so as to realize the connection of the components. Establish elastic elements, use spring dampers to simulate air springs, input the measured spring stiffness and shock absorber damping coefficient, and use multi-directional force unit simulation for various bushings, and input the various directional stiffness curves; establish a drive at the connection points between the four lower brackets of the suspension and the frame, and input the excitation after the vibration signal is collected; the rigid-flexible coupling model of the completed vehicle body suspension system is as follows: Figure 2 As shown;

[0077] (6) Sensor layout:

[0078] A triaxial acceleration sensor is installed at each suspended frame end and body end, and the coordinate axis direction of the sensor local coordinate system is parallel to the coordinate axis direction of the fixed coordinate system. Each acceleration sensor is connected to the vehicle vibration and noise test system through an independent channel, and the system is connected to the computer to observe, record and analyze the signal in real time through the test analysis software of the data acquisition system.

[0079] (7) Acceleration test on each suspension frame side and body side:

[0080] When conducting the actual vehicle ride comfort test, the vehicle was driven on a high-speed road at five speeds of 40km / h, 50km / h, 60km / h, 70km / h, and 80km / h, and the test speed was monitored by a speedometer. The vibration and noise test system was controlled by the test analysis software of the data acquisition system on the computer, and the sampling frequency was set to 1280Hz, the window function was hanning, the frequency resolution was 1.6Hz, and the sampling time was 14s; taking the 60km / h working condition as an example, the three-way acceleration time domain signals of the suspension 1 frame side and the body side were measured as follows Figure 3 to Figure 5 shown.

[0081] (8) Frame side acceleration signal processing:

[0082] Load the acceleration signal data of the frame side; use polynomial fitting to obtain a polynomial expression of a certain order, then use statement trend analysis to obtain the value of the trend item data polynomial, and finally subtract the trend item data obtained by fitting from the original data to obtain the data after the trend item is eliminated; take N=2, use the polynomial fitting processing statement "movmean" to perform sliding average processing on the data without the trend item to eliminate burrs and make the signal smooth; take the 60km / h working condition as an example, the Z-direction frame side acceleration time domain signal of the suspension 1 before and after processing is compared. Figure 6 As shown;

[0083] (9) Calculate the simulated vibration isolation rate: The processed frame side vibration acceleration time domain signal Input the rigid-flexible coupling model of the vehicle body suspension, perform simulation, and obtain the time domain signal of the vehicle body side acceleration response. right Use Fast Fourier Transform (FFT) to get the frequency domain amplitude Then according to the formula The simulated vibration isolation rate of each mount is obtained, where i = 1, 2, …, g. Taking the 60 km / h working condition as an example, the acceleration amplitudes of the Z-axis frame side and the body side acceleration of mount 1 and the vibration isolation rate are as follows: Figure 7 As shown;

[0084]

[0085] Where: X[k] is the kth frequency component in the frequency domain, representing the frequency domain amplitude, x[n] is the nth sampling point in the time domain, and N is the total number of sampling points of the signal;

[0086] (10) Calculate the test vibration isolation rate: Similarly, the acceleration time domain signals of the frame side and the body side obtained by the test are After FFT, the amplitudes in the frequency domain are obtained. Where i=1,2,…,g, then according to the formula The test vibration isolation rate of each mount is obtained; taking the 60km / h working condition as an example, the acceleration amplitudes of the Z-axis frame side and the body side acceleration of mount 1 and the vibration isolation rate are obtained as follows: Figure 8 As shown;

[0087] (11) The vibration isolation rate is calculated using an iterative algorithm: The core calculation formula is as follows:

[0088] K k =u k K i ,C k =v k C i ,i=0,1,2…,g (1)

[0089]

[0090]

[0091] Iteration process such as Fig. 9 As shown, the iterative process is as follows:

[0092] Step 1. Initial condition setting: Let the correction coefficient u k 、v k The initial value is 1;

[0093] Step 2. Calculation of suspension stiffness and damping coefficient: According to formula (1), calculate the modified suspension stiffness and damping coefficient.

[0094] Step 3. Calculation of simulated vibration isolation rate: After running the simulation and processing the data, the simulated vibration isolation rate of the suspension is obtained according to formula (2);

[0095] Step 4. Calculation of test vibration isolation rate: After processing the test data, calculate the test vibration isolation rate of the suspension according to formula (3);

[0096] Step 5. Convergence judgment: If the relative error between the simulated vibration isolation rate obtained in step 3 and the experimental vibration isolation rate obtained in step 4 is within the range of ±1%, the iteration ends. At this time, the simulated vibration isolation rate calculated in step 3 is the final result. Taking the 60km / h working condition as an example, the comparison between the Z-direction simulated vibration isolation rate and the experimental vibration isolation rate of the mount 1 obtained by iteration is as follows: Fig.10 As shown; otherwise, return to step 1, adjust the correction coefficient, and continue iterating.

[0097] In the description of the specification, the description with reference to the terms "one embodiment", "preferably", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention, and the schematic expressions of the above terms in this specification do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0098] The present invention is not limited to the above-mentioned embodiments. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention. The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

Claims

1. A method for calculating the vibration isolation rate of a vehicle body suspension system, characterized in that: The following steps are involved: Step S1. Obtaining a three-dimensional model of a vehicle body suspension system, vehicle body inertia parameters, vehicle body suspension system mechanical parameters, and a lateral stabilizer bar flexible body; creating corresponding constraint relationships according to the motion laws between the various components, thereby constructing a rigid-flexible coupling model of the vehicle body suspension system; Step S2. Acquire acceleration time domain signals of the frame side and the body side of the suspension system according to the actual vehicle ride comfort test; Step S3. Convert the time domain signal into a frequency domain amplitude by fast Fourier transform, and calculate the simulation vibration isolation rate and the test vibration isolation rate of the suspension system according to the vibration isolation rate formula; Step S4. According to the difference between the simulated vibration isolation rate and the experimental vibration isolation rate, stiffness and damping correction coefficients are introduced, and the accurate simulated vibration isolation rate is calculated through an iterative algorithm.

2. The method for calculating the vibration isolation rate of the vehicle body suspension system according to claim 1, characterized in that: Step S1 specifically includes: Step S101. Establishing a three-dimensional model of the vehicle body suspension system: obtaining geometric parameters of the vehicle body suspension system through given design drawings, establishing part drawings of each component according to the geometric parameters in a three-dimensional modeling software, and then establishing an assembly three-dimensional model of the vehicle body suspension system according to the positional relationship; Step S102. Test the inertia parameters of the vehicle body: Use the torsion pendulum method to measure the vehicle body mass m and the center of mass position O, and the moment of inertia J of the vehicle body around the X axis. xx , the moment of inertia around the Y axis J yy , the moment of inertia around the Z axis J zz , the inertia product of the vehicle body about the X-axis and Y-axis J xy , the inertia product J about the X-axis and Z-axis xz , the product of inertia J about the Y axis and the Z axis yz ; Step S103. Test the mechanical parameters of the vehicle body suspension system: the vehicle body suspension system includes g suspensions, g=2-8, which are named suspension 1, suspension 2, ..., suspension g from front to back; the axial stiffness K of the air spring is measured by the elastic body test system i ,i=1,2,…,g;The damping coefficient C of the shock absorber is measured by using the shock absorber dynamometer i , i=1,2,…,g; the six-directional stiffness curves of various bushings are measured by the elastic body testing system; Step S104. Flexible processing of the lateral stabilizer bar: meshing the three-dimensional digital model of the lateral stabilizer bar, assigning alloy steel material properties, constraining both ends of the stabilizer bar, and obtaining a data exchange file through modal comprehensive analysis.

3. The method for calculating the vibration isolation rate of the vehicle body suspension system according to claim 2, characterized in that: In step S101, the geometric parameters include upper and lower brackets, a lateral stabilizer bar, an air spring and various bushings.

4. The method for calculating the vibration isolation rate of the vehicle body suspension system according to claim 1, characterized in that: Step S2 specifically includes: Step S201. Sensor arrangement: a three-axis acceleration sensor is installed at each suspended frame end and body end, and the coordinate axis direction of the sensor local coordinate system is ensured to be parallel to the coordinate axis direction of the reference coordinate system; each acceleration sensor is connected to the vibration and noise test system through an independent channel; Step S202. Testing the acceleration of each suspension on the frame side and the body side: using a random input driving test method to perform a real vehicle ride comfort test, collecting acceleration time domain signals of each suspension on the frame side and the body side during the test; Step S203. Frame side acceleration signal processing: removing trend items and eliminating burrs from the collected frame side vibration acceleration signal.

5. The method for calculating the vibration isolation rate of the vehicle body suspension system according to claim 4, characterized in that: In step S202, when conducting a real vehicle smoothness test, the vehicle is driven on a high-loop road at five operating speeds of 40km / h, 50km / h, 60km / h, 70km / h, and 80km / h. The test vehicle speed is monitored by a speedometer, and a constant speed is maintained in the steady speed section, and the test section is passed at a specified uniform speed.

6. The method for calculating the vibration isolation rate of the vehicle body suspension system according to claim 4, characterized in that: In step S203, the trend item removal process is specifically performed using the following formula: Where: y detrended,i is the data after removing the trend term, y i is the original data, a0,a1,...,a n are the polynomial coefficients obtained by least squares fitting.

7. The method for calculating the vibration isolation rate of the vehicle body suspension system according to claim 4, characterized in that: In step S203, the burr elimination process is specifically performed using a five-point sliding average method, and the calculation formula of the five-point sliding average is: In the formula: x is the sampled data; y is the result after smoothing; m is the number of data points; 2N+1 is the average number of points; h is the weighted average factor.

8. The method for calculating the vibration isolation rate of the vehicle body suspension system according to claim 1, characterized in that: Step S3 specifically includes: Step S301. Calculate the vibration isolation rate of the vehicle body suspension: The processed frame side vibration acceleration time domain signal A i sl (t) Input the rigid-flexible coupling model of the vehicle body suspension, perform simulation, and obtain the time domain signal A of the vehicle body side acceleration response. i su (t); for A i sl (t), A i su (t) Using fast Fourier transform, we can get the frequency domain amplitude A i sl (ω), A i su (ω), then according to the formula T i s =20lg(A i su (ω) / A i sl (ω)) obtain the simulated vibration isolation rate of each mount, where i = 1, 2, …, g; A i sl (ω)=FFT(A i sl (t)) A i su (ω)=FFT(A i su (t)) Where: X[k] is the kth frequency component in the frequency domain, representing the frequency domain amplitude, x[n] is the nth sampling point in the time domain, and N is the total number of sampling points of the signal; Step S302: Process the data to obtain the test vibration isolation rate: The acceleration time domain signals A of the frame side and the body side obtained by the test are i tl (t), A i tu (t) After FFT, the amplitude A in the frequency domain is obtained. i tl (ω), A i tu (ω), where i = 1, 2, ..., g, then according to the formula T i t =20lg(A i tu (ω) / A i tl (ω)) to obtain the experimental vibration isolation rate of each mount.

9. The method for calculating the vibration isolation rate of the vehicle body suspension system according to claim 1, characterized in that: In step S4, the iterative algorithm calculation formula is as follows K k =u k K i ,C k =v k C i ,i=0,1,2…,g (1) T i k =20lg(A i ku (w) / A i kl (oh)) (2) T i t =20lg(A i tu (w) / A i tl (oh)) (3) In the above formulas, the subscript i=1, 2, ..., g represents the suspension number.

10. The method for calculating the vibration isolation rate of the vehicle body suspension system according to claim 9, characterized in that: The iterative process includes Step S401. Initial condition setting: Let the correction coefficient u k 、v k The initial value is 1; Step S402. Calculation of suspension stiffness and damping coefficient: Calculate the modified suspension stiffness and damping coefficient according to formula (1); Step S403. Calculation of simulated vibration isolation rate: After running the simulation and processing the data, the simulated vibration isolation rate of the suspension is obtained according to formula (2); Step S404. Calculation of test vibration isolation rate: After processing the test data, calculate the test vibration isolation rate of the suspension according to formula (3); Step S405. Convergence judgment: If the relative error between the simulated vibration isolation rate obtained in step 403 and the experimental vibration isolation rate obtained in step 404 is within the range of ±1%, the iteration ends; at this time, the simulated vibration isolation rate calculated in step 403 is the final result; otherwise, return to step 401, adjust the correction coefficient, and continue iteration.

Images