A method and system for identifying the shudder of an automotive powertrain using the natural frequency

Abstract

The present invention provides a method and a system for identifying the shudder phenomenon of an automotive drive system by using the natural frequency. The method includes: obtaining the measured value of the vibration physical quantity of the vehicle, and obtaining the natural frequency, i.e., the peak frequency, of the automotive drive system from the frequency spectrum diagram of the vehicle vibration physical quantity; calculating the shudder natural frequency f of the drive system: comparing the shudder natural frequency f of the drive system with the natural frequency of the automotive drive system to determine whether the vibration corresponding to the peak frequency is caused by the shudder of the drive system. The present invention can improve the accuracy of identifying the shudder phenomenon of the automotive drive system, provide a reference for the mutual matching between the various components of the automotive drive system, and further improve the automotive NVH performance caused by the shudder of the automotive drive system.

Description

Technical Field

[0001] The present invention relates to the field of automotive power NVH, and particularly to a technology for identifying the shudder phenomenon of an automotive transmission system. Background Art

[0002] The automotive power transmission system is a torsional vibration system with multiple degrees of freedom. Sudden instantaneous operations by the driver (such as suddenly stepping on the accelerator pedal, suddenly releasing the accelerator pedal, etc.) will cause a sudden change in the engine torque. The engine torque, as the excitation force, will trigger the shudder of the transmission system when its frequency is consistent with the natural frequency of the transmission system from the torque converter to the half shaft. The shudder of the transmission system is directly related to the dynamic characteristics of the transmission system. The shudder of the transmission system will bring highly sensitive vibrations and noises to the cockpit, affecting the ride and drive comfort. The natural frequency of the transmission system shudder is closely related to the stiffness of the elastic elements and the inertia of the mass elements of the transmission system. Revealing the dynamic characteristics of the automotive transmission system shudder and seeking measures to reduce the impact of the transmission system shudder are one of the important research topics in the field of automotive power NVH (vibration and noise). Accurately identifying the shudder of the automotive transmission system is very important for suppressing the occurrence of shudder and optimizing the matching of the transmission system, and can also provide a basis for solving the vibration and noise problems of the transmission system. Summary of the Invention

[0003] The purpose of the present invention is to provide a method and system for identifying the shudder phenomenon of an automotive transmission system using the natural frequency, as an effective auxiliary verification method for identifying the shudder phenomenon of an automotive transmission system through experimental testing means, providing a reference for the mutual matching between the various components of the automotive transmission system, and thereby improving the automotive NVH performance caused by the shudder of the automotive transmission system.

[0004] The technical solution of the present invention is as follows:

[0005] The present invention provides a method for identifying the shudder phenomenon of an automotive transmission system using the natural frequency, and the method includes:

[0006] Step 1, obtaining measurement data of vehicle vibration physical quantities, where the vibration physical quantities include vibration acceleration, vibration velocity, or vibration displacement.

[0007] According to an embodiment of the present invention, for the vibration physical quantities of the vehicle, issue an instruction to the driver to suddenly step on the accelerator pedal when starting. Arrange vibration sensors on the housing of the automotive transmission system (such as the transmission housing). Use professional software for vibration measurement to measure the vibration physical quantities (such as acceleration).

[0008] Step 2, performing data analysis on the vehicle vibration physical quantities

[0009] Perform a Fast Fourier Transform (FFT) calculation on the physical quantity of vehicle vibration. Obtain the frequency spectrum diagram of the physical quantity of vibration (such as the vibration acceleration of the transmission system housing), and acquire the peak frequency, which is the natural frequency of the automotive transmission system.

[0010] Step 3, calculate the shudder natural frequency f of the transmission system.

[0011] Step 4, compare the shudder natural frequency f of the transmission system with the natural frequency of the transmission system. If the two are close or even the same, it is determined that the vibration corresponding to the peak frequency is caused by the shudder of the transmission system. According to the test results, if the difference between the two is within 4.4%, it can be considered close.

[0012] In the above technical solution of the present invention, first, measure the physical quantity of vehicle vibration and perform FFT (Fast Fourier Transform) calculation on it. Obtain the frequency spectrum diagram of the vibration acceleration of the transmission system housing. Further, obtain the peak value from the frequency spectrum diagram, and the corresponding frequency is called the peak frequency. Since one of the reasons for the appearance of the peak frequency is the inherent characteristics of the automotive transmission system, the peak frequency at this time is the natural frequency of the automotive transmission system. Due to the complex structure of the automotive transmission system, its natural frequency is related to the inertia and stiffness of multiple components. Therefore, the automotive transmission system has multiple natural frequencies. Therefore, for the problem vehicle with shudder phenomenon, it may not be possible to identify the shudder natural frequency from the frequency spectrum diagram of the vibration acceleration of the transmission system housing, that is, it is inaccurate to identify the shudder natural frequency from the frequency spectrum diagram of the vibration acceleration of the transmission system housing. Therefore, the present invention proposes to further calculate the shudder natural frequency f of the transmission system, and then compare the calculated shudder natural frequency f of the transmission system with the natural frequency of the automotive transmission system identified from the frequency spectrum diagram before. If the two are close or even the same, it can be determined that the vibration corresponding to the peak frequency is caused by the shudder of the transmission system.

[0013] For the shudder natural frequency f of the transmission system, the present invention further proposes two unique calculation formulas. One is a relatively accurate and comprehensive calculation formula:

[0014]

[0015] where K1 is the stiffness of the torque converter, K2 is the stiffness of the transmission, K3 is the stiffness of the differential, K 4左 is the stiffness of the left half shaft, K 4右 is the stiffness of the right half shaft, J 1泵 is the inertia of the pump impeller, J 1涡 is the inertia of the turbine, J2 is the inertia of the transmission, J3 is the inertia of the differential, J 4左 is the inertia of the left half shaft, J 4右 is the inertia of the right half shaft, R1 is the gear ratio, and R2 is the final drive ratio.

[0016] Another calculation formula is a simplification based on the above first calculation formula when some parameters are incomplete:

[0017]

[0018] where K 4左 is the stiffness of the left half shaft, K 4右 is the stiffness of the right half shaft, J 1泵 is the inertia of the pump impeller, J 1涡 is the inertia of the turbine, R1 is the gear ratio, and R2 is the main reduction ratio.

[0019] The advantages of the present invention are as follows:

[0020] The method for identifying the shudder phenomenon of the automotive powertrain proposed by the present invention judges whether the vibration corresponding to the peak frequency of the natural frequency in the spectrogram is caused by the shudder of the powertrain by comparing the calculated shudder natural frequency f of the powertrain with the natural frequency identified from the spectrogram, thereby identifying the shudder phenomenon and making the identification more accurate.

[0021] Meanwhile, the present invention proposes a unique calculation formula for the shudder natural frequency f of the powertrain, reveals the dynamic parameters related to the shudder natural frequency of the automatic transmission powertrain, and identifies the shudder phenomenon of the automotive powertrain. The results show that the calculation formula is only related to a few dynamic parameters, namely the stiffness of the pump impeller of the torque converter, the inertia of the pump impeller and turbine of the torque converter, the stiffness and inertia of the transmission, the stiffness and inertia of the differential, the stiffness and inertia of the left half shaft, the stiffness and inertia of the right half shaft, the gear ratio, the main reduction ratio, etc., a total of 13 parameters. The test results differ from the calculation results by 1.8%, which can be considered relatively consistent. Further, the present invention also derives a simplified calculation formula. The results show that the simplified calculation formula is only related to 6 parameters, namely the inertia of the pump impeller, the inertia of the turbine, the stiffness of the left half shaft, the stiffness of the right half shaft, the gear ratio, and the main reduction ratio. The calculated value differs from the test measurement value by 4.4%. Even when the relevant calculation parameters are incomplete and inaccurate, this result can still be used as a strong basis for judging the occurrence of the shudder phenomenon in the automatic transmission powertrain. Description of the Drawings

[0022] Figure 1 is the component structure of the powertrain.

[0023] Figure 2 is the flowchart of the method for identifying the shudder phenomenon of the automotive powertrain using the natural frequency.

[0024] Figure 3 is the flowchart for calculating the natural frequency of the shudder of the powertrain. Detailed Embodiments

[0025] The present invention will be further described below in conjunction with the accompanying drawings of the specification. The described embodiments are only the embodiments of the present invention patent, rather than all embodiments. All other embodiments obtained without creative efforts based on the embodiments of the present invention patent fall within the protection scope of the present invention patent.

[0026] This embodiment takes a typical automatic transmission system of an automobile as an example, as Figure 1 shown. The automobile transmission system referred to in this embodiment refers to the assembly of all power transmission devices between the engine and the driving wheels. Its function is to transmit the power of the engine to the driving wheels. The automatic transmission system 10 of the automobile referred to in this embodiment includes an engine 101, a torque converter 102, a pump impeller 103, a turbine 104, a transmission 105, a differential 106, a left half shaft 107, a right half shaft 108, a left driving wheel 109, and a right driving wheel 110. After the rotational speeds of the pump impeller 103 and the turbine 104 in the torque converter 102 are synchronized, a sudden operation by the driver (such as suddenly stepping on the accelerator pedal, suddenly releasing the accelerator pedal, etc.) will cause a sudden change in the engine torque, thereby triggering a shudder of the transmission system. The torque of the engine 101 is first transmitted to the pump impeller 102 of the torque converter. Therefore, when calculating the natural frequency of the transmission system shudder, the first component to be considered is the pump impeller 103. On the other hand, the left driving wheel 109 and the right driving wheel 110 are restricted by the ground. Therefore, the left driving wheel 109 and the right driving wheel 110 are not considered when calculating the natural frequency of the transmission system shudder. Therefore, when calculating the natural frequency of the transmission system shudder, the stiffness and inertia of the transmission system from the pump impeller 103 to the left half shaft 107 and the right half shaft 108 are considered, including the pump impeller 103, the turbine 104, the transmission 105, the differential 106, the left half shaft 107, and the right half shaft 108.

[0027] As Figure 2 shown, the present invention embodiment provides a method for identifying the shudder phenomenon of an automobile transmission system, which includes the following steps:

[0028] S201, obtaining measurement data of vehicle vibration physical quantities

[0029] Since a sudden change in the engine torque will cause a shudder phenomenon of the automobile transmission system, and a sudden operation by the driver (such as suddenly stepping on the accelerator pedal, suddenly releasing the accelerator pedal, etc.) will cause a sudden change in the engine torque. Therefore, when measuring the vibration physical quantities of a problem vehicle with a shudder phenomenon, an instruction to suddenly step on the accelerator pedal during starting is sent to the driver. Since the shudder phenomenon is related to the automobile transmission system, vibration sensors are arranged on the housing of the automobile transmission system (such as the transmission housing). Professional software for vibration measurement is used to measure vibration physical quantities (such as acceleration).

[0030] S202. Data analysis of vehicle vibration physical quantities

[0031] After measuring the vibration acceleration of the transmission system housing under the condition of quickly stepping on the accelerator pedal at startup, perform FFT (Fast Fourier Transform) calculation on it. Obtain the frequency spectrum diagram of the vibration acceleration of the transmission system housing. Further, obtain the peak value from the frequency spectrum diagram, and the corresponding frequency is called the peak frequency. Since one of the reasons for the peak frequency is the inherent characteristics of the automotive transmission system, the peak frequency at this time is the natural frequency of the automotive transmission system.

[0032] However, due to the complex structure of the automotive transmission system, its natural frequency is related to the inertia and stiffness of multiple components. Therefore, the automotive transmission system has multiple natural frequencies. Therefore, for the problem vehicle with shudder phenomenon, it may not be possible to identify the shudder natural frequency from the frequency spectrum diagram of the vibration acceleration of the transmission system housing, and further identification is required.

[0033] S203. Calculate the shudder natural frequency f of the transmission system.

[0034] S204. Compare the shudder natural frequency f of the transmission system obtained in the above step S203 with the natural frequency of the automotive transmission system obtained in S202.

[0035] S205. If the calculated value of the shudder natural frequency is close to or even the same as the peak frequency of the vibration acceleration of the transmission system housing, it can be further determined that the vibration corresponding to the peak frequency is caused by the shudder of the transmission system.

[0036] In the above step S203, in order to identify the shudder natural frequency from the frequency spectrum diagram of the vibration acceleration of the transmission system housing, two calculation formulas are provided in the embodiments of the present invention to calculate the calculated value of the shudder natural frequency f of the transmission system.

[0037] The two formulas for calculating the shudder natural frequency f of the transmission system are respectively:

[0038]

[0039] and

[0040] where, K1 is the stiffness of the torque converter, K2 is the stiffness of the transmission, K3 is the stiffness of the differential, K 4左 is the stiffness of the left half shaft, K 4右 is the stiffness of the right half shaft, J 1泵 is the inertia of the pump impeller, J 1涡 is the inertia of the turbine, J2 is the inertia of the transmission, J3 is the inertia of the differential, J 4左 is the inertia of the left half shaft, J 4右$I$ is the inertia of the right half shaft, $R_1$ is the gear ratio, and $R_2$ is the main reduction ratio.

[0041] The above two calculation formulas are derived through the following methods:

[0042] 1. Basic formula for the inherent frequency of torsional vibration of the transmission system

[0043] In the embodiment of the present invention, the vehicle transmission system is regarded as a single-degree-of-freedom undamped vibration system. The natural frequency of free vibration of this system can be written as:

[0044]

[0045] where $f$ is the inherent frequency of torsional vibration of the transmission system, $K$ e is the equivalent stiffness of the elastic element of the transmission system, and $J$ e is the equivalent inertia of the mass element of the transmission system.

[0046] 2. Equivalent stiffness of the elastic element of the transmission system

[0047] The elastic elements of the actual transmission system are relatively complex. For the convenience of analysis, the complex elastic element system is simplified into an equivalent elastic element. In the embodiment of the present invention, the equivalent stiffness of the elastic element system is calculated for substitution. Since the contribution of the elastic element group of the transmission system to the displacement of the transmission system is the sum, the elastic elements of the transmission system are in series relationship. At this time, the equivalent stiffness of the elastic element of the transmission system can be written as:

[0048]

[0049] where $K$ 1e is the equivalent stiffness of the torque converter 102, $K$ 2e is the equivalent stiffness of the transmission 105, $K$ 3e is the equivalent stiffness of the differential 106, $K$ 4e is the equivalent stiffness of the half shaft.

[0050] Since the elastic element is an energy storage element, the principle of conservation of potential energy (that is, the potential energy of the original system is equal to the potential energy of the simplified system) is used to determine the equivalent stiffness $K$ 1e of the torque converter 102 and the equivalent stiffness $K$ 2e of the transmission 105.

[0051] If the stiffness of the elastic element group of the transmission system is equivalent to the half shaft, for the torque converter 102, the potential energy conservation equation can be written as:

[0052]

[0053] where $K_1$ is the stiffness of the torque converter 102, $K$ 1eis the equivalent stiffness of the hydrodynamic torque converter 102, θ1 is the angular displacement of the hydrodynamic torque converter 102, and θ 3e is the equivalent angular displacement equivalent to the half shaft. Simplifying Equation (3), we get:

[0054]

[0055] where θ2 is the angular displacement of the transmission 105, R1 is the gear ratio, and R2 is the final drive ratio.

[0056] For the transmission 105, the potential energy conservation equation can be written as:

[0057]

[0058] where K2 is the stiffness of the transmission 105, K 2e is the equivalent stiffness of the transmission 105, θ2 is the angular displacement of the transmission 105, and θ 3e is the equivalent angular displacement equivalent to the half shaft. Simplifying Equation (5), we get:

[0059]

[0060] Since the stiffness of the elastic element group of the drive system is equivalent to the half shaft, the equivalent stiffness K 3e of the differential 106 is the stiffness K3 of the differential 106, and the equivalent stiffness K 4e of the half shaft is the stiffness K4 of the half shaft.

[0061] For the half shaft, the left half shaft 107 and the right half shaft 108 are in series. The equivalent stiffness of the half shaft is:

[0062] K 4e = K4 = K 4左 + K 4右 (7)

[0063] where K 4左 and K 4右 are the stiffnesses of the left half shaft 107 and the right half shaft 108 respectively.

[0064] Substituting Equations (4), (6), and (7) into Equation (2), we can obtain the equivalent stiffness of the elastic elements of the drive system:

[0065]

[0066] 3. Equivalent inertia of the mass elements of the drive system

[0067] The moment of inertia of the actual transmission system is continuously distributed. The equivalent inertia of the mass elements of the transmission system is determined by using the energy storage characteristics of the mass elements. Since the contribution of the mass element group of the transmission system to the displacement of the transmission system is the sum, the mass elements of the transmission system are in series. At this time, the equivalent inertia of the mass elements of the transmission system can be written as:

[0068] J e = J 1e + J 2e + J 3e + J 4e (9)

[0069] Among them, J 1e is the equivalent inertia of the hydrodynamic torque converter 102, J 2e is the equivalent inertia of the transmission 105, J 3e is the equivalent inertia of the differential 106, J 4e is the equivalent inertia of the half shaft.

[0070] Since the mass element is an energy storage element, the principle of conservation of kinetic energy (i.e., the kinetic energy of the original system is equal to the kinetic energy of the simplified system) is used to determine the equivalent inertia J 1e of the hydrodynamic torque converter 102 and the equivalent inertia J 2e of the transmission 105.

[0071] If the inertia of the mass element group of the transmission system is equivalent to the half shaft. For the hydrodynamic torque converter 102, the kinetic energy conservation equation can be written as:

[0072]

[0073] Among them, J1 is the inertia of the hydrodynamic torque converter 102, J 1泵 is the inertia of the pump impeller 103, J 1涡 is the inertia of the turbine 104, J 1e is the equivalent inertia of the hydrodynamic torque converter 102, is the angular acceleration of the hydrodynamic torque converter 102, is the equivalent angular acceleration equivalent to the half shaft. Simplifying Equation (9), we can get:

[0074]

[0075] Among them, is the angular acceleration of the transmission 105, R1 is the gear ratio, and R2 is the main reduction ratio.

[0076] For the transmission 105, the kinetic energy conservation equation can be written as:

[0077]

[0078] Among them, J2 is the inertia of the transmission 105, and J 2e is the equivalent inertia of the transmission 105, is the angular acceleration of the transmission 105, and is the equivalent angular acceleration equivalent to the half shaft. Simplifying Equation (12), we can obtain:

[0079]

[0080] Since the inertia of the mass element group of the drive system is equivalent to the half shaft, the equivalent inertia J 3e of the differential 106 is the inertia J3 of the differential 106, and the equivalent inertia J 4e of the half shaft is the inertia J4 of the half shaft.

[0081] The equivalent inertia of the half shaft is:

[0082] J 4e = J4 = J 4左 + J 4右 (14)

[0083] Among them, J 4左 and J 4右 are the inertias of the left half shaft 107 and the right half shaft 108 respectively.

[0084] Substituting Equations (11), (13), and (14) into Equation (9), we can obtain the equivalent inertia of the elastic element of the drive system:

[0085]

[0086] 4. Shudder natural frequency of the drive system

[0087] Substituting Equations (8) and (15) into Equation (1), we can obtain the shudder natural frequency of the drive system involved in the present invention as:

[0088]

[0089] Therefore, referring to Figure 3 , the calculation steps of the shudder natural frequency of the drive system are as follows:

[0090] Step S301: Determine the stiffness K1 of the torque converter 102, the stiffness K2 of the transmission 105, the stiffness K3 of the differential 106, the stiffness K 4左 of the left half shaft 107, 4右 and the stiffness K of the right half shaft 108.

[0091] Step S302: Determine the inertia J 1泵 of the pump impeller 103, the inertia J 1涡, the inertia J2 of the transmission 105, the inertia J3 of the differential 106, and the inertia J of the left half shaft 107 4左 , the inertia J of the right half shaft 108 4右 .

[0092] Step S303: Determine the gear ratio R1 and the main reduction ratio R2.

[0093] Step S304: The natural frequency of the driveline shudder can be calculated using Equation (16).

[0094] In some cases, when the exact values of all the above parameters cannot be given, for the calculation of the natural frequency of the driveline shudder, Equation (16) can be reasonably simplified to use a simplified formula.

[0095] The derivation is as follows:

[0096] Generally, the stiffness K of the left half shaft 107 4左 , the stiffness K of the right half shaft 108 4右 is much smaller than the stiffness term of the torque converter 102 the stiffness term of the transmission 105 and the stiffness K3 of the differential 106. At the same time, the sum of the inertia terms of the pump impeller 103 and the turbine 104 is much greater than the inertia term of the transmission 105 the inertia J3 of the differential 106, the inertia J of the left half shaft 107 4左 , and the inertia J4 of the right half shaft 108.

[0097] Therefore, Equation (16) can be further simplified to:

[0098]

[0099] In another embodiment of the present invention, a system for identifying the shudder phenomenon of an automotive driveline using the natural frequency is provided. The system includes the following unit modules:

[0100] A data acquisition module for acquiring measurement data of vehicle vibration physical quantities, where the vibration physical quantities include vibration acceleration, vibration velocity, or vibration displacement.

[0101] An analysis module for performing a fast Fourier transform (FFT) calculation on the vehicle vibration physical quantities, obtaining the frequency spectrum diagram of the vibration physical quantities, and acquiring the peak frequency, which is the natural frequency of the automotive driveline.

[0102] A calculation module for calculating the shudder natural frequency f of the driveline. The calculation formula is as in the previous embodiment.

[0103] A comparison module is configured to compare the shudder natural frequency f of the drive system with the natural frequency of the vehicle drive system. If the two values are relatively close or even the same, it is determined that the vibration corresponding to the peak frequency is caused by drive system shudder.

[0104] In a further embodiment of the present invention, the applicant applied the above method in the actual identification of drive system shudder phenomenon. In the case of obvious shudder during the first-gear start of a certain model of automatic transmission vehicle, the start process of the vehicle was tested. The vibration acceleration of the transmission housing was measured. The test results show that the peak frequency of the vibration acceleration of the transmission housing during the shudder stage is 2.7 Hz. The shudder natural frequency of the drive system calculated by formula (16) is 2.65 Hz. The difference between the two is 1.8%, and it is considered that the two are relatively close. It should be noted that the shudder natural frequency of the drive system calculated by the simplified formula (17) is 2.82 Hz. Although the difference from the test measurement value is 4.4%, it can still be used as a judgment basis for identifying the shudder problem of the drive system under the condition that the relevant calculation parameters are incomplete and inaccurate.

Claims

1. A method for identifying the shudder phenomenon of an automotive drive system using the natural frequency, characterized in that, The vehicle transmission system includes an engine, a torque converter, a pump impeller, a turbine, a transmission, a differential, a left half shaft, a right half shaft, a left drive wheel, and a right drive wheel. The method includes: Step 1: Obtain the measurement data of the vehicle vibration physical quantity, where the vibration physical quantity includes vibration acceleration, vibration velocity, or vibration displacement; Step 2: Perform data analysis on the vehicle vibration physical quantity Perform a fast Fourier transform (FFT) calculation on the vehicle vibration physical quantity to obtain the frequency spectrum diagram of the vibration physical quantity, and obtain the peak frequency, which is the natural frequency of the vehicle transmission system; Step 3: Calculate the shudder natural frequency f of the transmission system. The calculation formula: Among them, K1 is the stiffness of the torque converter, K2 is the stiffness of the transmission, K3 is the stiffness of the differential, is the stiffness of the left half shaft, is the stiffness of the right half shaft, is the inertia of the pump impeller, is the inertia of the turbine, J2 is the inertia of the transmission, J3 is the inertia of the differential, is the inertia of the left half shaft, is the inertia of the right half shaft, R1 is the gear ratio, and R2 is the final drive ratio; Step 4: Compare the shudder natural frequency f of the transmission system with the natural frequency of the vehicle transmission system. If the two values are close or even the same, it is determined that the vibration corresponding to the peak frequency is caused by the shudder of the transmission system.

2. The method for identifying the shudder phenomenon of an automotive powertrain using the natural frequency according to claim 1, wherein In the case where the accurate values of all parameters cannot be given, a simplified formula is used for the calculation of the shudder natural frequency of the transmission system: Among them, is the stiffness of the left half shaft, is the stiffness of the right half shaft, is the inertia of the pump impeller, is the inertia of the turbine, R1 is the gear ratio, and R2 is the main reduction ratio.

3. The method for identifying the shudder phenomenon of an automotive drive system using the natural frequency according to claim 1 or 2, characterized in that In Step 1, the vibration physical quantity of the transmission housing is measured under the condition of quickly stepping on the accelerator pedal when the vehicle starts.

4. A system for identifying the shudder phenomenon of an automotive drive system using the natural frequency, characterized in that, The vehicle transmission system includes an engine, a torque converter, a pump impeller, a turbine, a transmission, a differential, a left half shaft, a right half shaft, a left drive wheel, and a right drive wheel, including: A data acquisition module for obtaining the measurement data of the vehicle vibration physical quantity, where the vibration physical quantity includes vibration acceleration, vibration velocity, or vibration displacement; A data analysis module for performing a fast Fourier transform (FFT) calculation on the vehicle vibration physical quantity to obtain the frequency spectrum diagram of the vibration physical quantity, and obtaining the peak frequency, which is the natural frequency of the vehicle transmission system; A calculation module for calculating the shudder natural frequency f of the transmission system. The calculation formula: Among them, K1 is the stiffness of the torque converter, K2 is the stiffness of the transmission, K3 is the stiffness of the differential, is the stiffness of the left half shaft, is the stiffness of the right half shaft, is the inertia of the pump impeller, is the inertia of the turbine, J2 is the inertia of the transmission, J3 is the inertia of the differential, is the inertia of the left half shaft, is the inertia of the right half shaft, R1 is the gear ratio, and R2 is the final drive ratio; A comparison module for comparing the shudder natural frequency f of the transmission system with the natural frequency of the vehicle transmission system. If the two values are close or even the same, it is determined that the vibration corresponding to the peak frequency is caused by the shudder of the transmission system.

5. The system for identifying the shudder phenomenon of an automotive powertrain using the natural frequency according to claim 4, wherein In the case where the accurate values of all parameters cannot be given, a simplified formula is used for the calculation of the shudder natural frequency of the transmission system: Among them, is the stiffness of the left half shaft, is the stiffness of the right half shaft, is the inertia of the pump impeller, is the inertia of the turbine, R1 is the gear ratio, and R2 is the main reduction ratio.

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