Damping control method, mechanism and vehicle powertrain for a vehicle driveline

Abstract

The application discloses a damping control method for a vehicle transmission system, wherein the method comprises the following steps: a first step of acquiring operation parameters of the vehicle transmission system; a second step of inputting the operation parameters acquired in the first step into a parameter identification model to determine corresponding suspension system parameters; a third step of inputting the suspension system parameters determined in the second step into a sliding mode observer to acquire a load torque observation value and an axle torsion observation value; and a fourth step of performing damping control on the vehicle transmission system based on the load torque observation value and the axle torsion observation value acquired in the third step to eliminate speed fluctuation of a motor or a wheel. The application also discloses a mechanism for performing damping control on the vehicle transmission system by using the method, and a vehicle power assembly comprising the mechanism.

Description

Technical Field

[0001] This invention relates to the field of vehicle technology, and more specifically, to a damping control method for a vehicle transmission system, a mechanism for damping control of a vehicle transmission system using this method, and a vehicle powertrain including the mechanism. Background Technology

[0002] In electric vehicles, hybrid vehicles, and other new energy vehicles, the vehicle drivetrain is a core component that provides power to the vehicle. Typically, the suspension system is used to dampen and control the drivetrain to reduce vehicle vibration and improve the passenger experience.

[0003] Existing damping control technologies typically require manually or adaptively using Fast Fourier Transform (FFT) to filter out fluctuating signals from the vehicle's rotational speed. These signals are then adjusted in phase and amplitude using a filter before being used as compensation for the given torque of the load. This technology involves extensive data storage (for FFT analysis to determine the resonant frequency) and significant manual calibration processes (e.g., calibrating the compensation torque based on the amplitude and frequency determined by the FFT analysis). In particular, during actual vehicle testing, individual calibration is required based on different operating conditions and driving environments, resulting in a large workload and high manpower consumption.

[0004] Other damping control technologies use neural network learning for torque compensation; however, the self-learning process usually takes a long time, increasing time costs.

[0005] Even with active damping control implemented using the aforementioned technologies, wear and tear on vehicle components (such as the reducer) can still lead to the failure of the vehicle's anti-shake function. Summary of the Invention

[0006] In view of this, according to a first aspect of the present invention, a damping control method for a vehicle transmission system is provided, wherein the method includes the following steps:

[0007] The first step is to obtain the operating parameters of the vehicle's transmission system;

[0008] The second step is to input the operating parameters obtained in the first step into the parameter identification model in order to determine the corresponding suspension system parameters.

[0009] The third step involves inputting the suspension system parameters determined in the second step into the sliding mode observer to obtain load torque and shaft torsion observation values; and

[0010] The fourth step involves applying damping control to the vehicle's transmission system based on the load torque and shaft torque observations obtained in the third step, in order to eliminate speed fluctuations in the motor or wheels.

[0011] The operating parameters include at least one of the following: motor torque, motor reducer moment of inertia, and actual rotational speed of the motor or wheel.

[0012] The parameter identification model stores a minimum variance evaluation function between the estimated speed and the actual speed of the motor or wheel, and the parameter identification model starts or stops the parameter identification process based on the evaluation result of the minimum variance evaluation function.

[0013] The method also includes:

[0014] The load torque observations obtained in the third step are fed back into the parameter identification model, and the parameter identification model determines the estimated speed of the motor or wheel based on the received load torque observations, motor torque, and motor reducer rotational inertia.

[0015] The parameter identification model uses autoregressive least squares to determine the estimated rotational speed of the motor or wheel.

[0016] The method further includes a fifth step between the third and fourth steps, in which a high-pass filter is used to filter out the DC component in the shaft torsion observation and the phase of the filtered shaft torsion observation is adjusted to obtain a shaft torsion compensation value for compensating for half-shaft ripple torque.

[0017] The suspension system parameters include the elasticity coefficient and the load inertia.

[0018] The parameter identification model is further configured to acquire the suspension system parameters offline. In this offline mode, the load inertia is acquired by using a lift to raise the vehicle and by adopting closed-loop speed control and a motor mechanical model; and the elastic coefficient is acquired by using a linear frequency-modulated torque signal and a fast Fourier transform.

[0019] According to a second aspect of the present invention, a mechanism for damping control of a vehicle transmission system using the method described above is provided, wherein the mechanism comprises:

[0020] A detection device configured to acquire operating parameters of a vehicle's transmission system;

[0021] A parameter identification module is configured to determine the corresponding suspension system parameters based on the operating parameters detected by the detection device.

[0022] A sliding mode observer configured to acquire load torque and shaft torsion observations based on the suspension system determined by the parameter identification module; and

[0023] A control module configured to perform damping control on the vehicle drive system based on torque and shaft torsion observations obtained by the sliding mode observer, in order to eliminate speed fluctuations of the motor or wheels.

[0024] According to a third aspect of the invention, a vehicle powertrain including the mechanism described above is provided.

[0025] The damping control method for vehicle transmission systems according to the present invention can achieve at least one of the following advantages:

[0026] - Adopting an adaptive sliding mode observer and parameter identification model reduces the manual calibration process and ensures the robustness of damping control;

[0027] - The parameter identification model can obtain the parameters required by the observer in an online or offline manner, making it suitable for a wider range of application scenarios;

[0028] - Online observation methods utilize the minimum variance evaluation function for online parameter identification, ensuring system stability; and

[0029] Even when vibration frequency shifts due to wear in the vehicle's transmission system, the active damping effect can be corrected in time, preventing vibration suppression from failing. Attached Figure Description

[0030] By incorporating the figures in this article and subsequently the appendix Figure 1 The specific embodiments used to illustrate certain principles of the invention will make other features and advantages of the device of the invention clearer or more specifically explained.

[0031] Figure 1 A schematic diagram of a conventional vehicle drivetrain is shown.

[0032] Figure 2 A schematic diagram illustrating the operation of a damping control method for a vehicle transmission system according to an exemplary embodiment of the present invention is shown. Detailed Implementation

[0033] The damping control method and mechanism for a vehicle transmission system according to the present invention will now be described with reference to the accompanying drawings and embodiments. In the following description, numerous specific details are set forth to enable those skilled in the art to gain a more complete understanding of the invention. However, it will be apparent to those skilled in the art that implementation of the invention may not include some of these specific details. Instead, the invention may be conceived to be practiced with any combination of the following features and elements, regardless of whether they relate to different embodiments. Therefore, the following aspects, features, embodiments, and advantages are illustrative only and should not be considered as elements or limitations of the claims.

[0034] Figure 1 A schematic diagram of a conventional vehicle drivetrain is shown. In this document, "vehicle drivetrain" specifically includes a three-in-one electric drive consisting of a motor, a reducer, and a motor driver. For example... Figure 1 As shown, the input of the reducer is connected to the motor driver, and the output of the reducer is connected to the wheel (here referring to the "drive wheel", also known as the "load" in this article) via a half-shaft.

[0035] In vehicle transmission systems, unwanted vibrations primarily originate from two components of fluctuating torque: the first is the load torque generated by wheel-end friction, vehicle weight, etc., and the second is the elastic shaft torque resulting from axle torsional deformation and backlash elasticity within the reducer. To suppress vehicle vibrations, this invention focuses on compensating for the second component of elastic torque to eliminate fluctuations in motor or wheel speed.

[0036] Figure 2 A schematic diagram illustrating the operation of a damping control method for a vehicle transmission system according to an exemplary embodiment of the present invention is shown.

[0037] like Figure 2 As shown, this method uses a sliding mode observer to observe the fluctuation of half-shaft torque (hereinafter referred to as "shaft torque") in the vehicle transmission system. The vehicle transmission system model parameters involved in the sliding mode observer (especially suspension system parameters, such as elastic coefficient and load inertia) can be obtained through online parameter identification or offline parameter identification.

[0038] The operation process of the damping control method of the present invention will be described below in conjunction with these two different parameter identification methods.

[0039] Online observation

[0040] In online observation mode, the operating parameters of the vehicle's transmission system are first acquired. These operating parameters include, but are not limited to, at least one of the following: motor torque, motor reducer rotational inertia, and actual rotational speed of the motor or wheel (which can be obtained through ABS wheel speed sensors).

[0041] Subsequently, the acquired operating parameters of the vehicle transmission system are substituted into the parameter identification model to determine the corresponding suspension system parameters, such as the suspension system's elastic coefficient and load inertia. This parameter identification model can employ autoregressive least squares to obtain these suspension system parameters, thereby reducing the amount of data processing required.

[0042] Furthermore, this parameter identification model also utilizes a minimum variance evaluation function for rotational speed during the acquisition of suspension system parameters. Specifically, the parameter identification model can pre-store a minimum variance evaluation function between the actual rotational speed of the motor or wheel and the target estimated rotational speed. The parameter identification model can start or stop the parameter identification process based on the evaluation result of this evaluation function to obtain the corresponding suspension system parameters.

[0043] The obtained suspension system parameters can be calibrated and substituted into the sliding mode observer to obtain load torque observations and axle torsion observations. These load torque observations and axle torsion observations can be further used for damping control of the drivetrain. Specifically, the obtained axle torsion observations can be fed back as compensation to the drivetrain's half-shafts to eliminate speed fluctuations in the motor or wheels.

[0044] Optionally, after obtaining the corresponding observation results (e.g., shaft torsion observation values), a high-pass filter can be used to filter out the DC component in the shaft torsion observation values, and the filtered shaft torsion observation values ​​can be phase-adjusted to obtain shaft torsion compensation values ​​for compensating for half-shaft ripple torque.

[0045] Furthermore, the observations obtained by the sliding mode observer (e.g., load torque observations) can be fed back into the parameter identification model. This model can determine the estimated speed of the motor or wheels based on the received load torque observations, motor torque, and the moment of inertia of the motor reducer, thereby adjusting the final suspension system parameters in real time to achieve closed-loop control. Optionally, the parameter identification model uses autoregressive least squares to determine the estimated speed of the motor or wheels.

[0046] Offline observation

[0047] In offline observation mode, the vehicle is first lifted by a hoist, and the load inertia of the suspension system is calculated by using closed-loop speed control and mathematical models of the vehicle's transmission system (especially the mathematical model formula of the motor). Then, by injecting a linear frequency modulation signal (also known as a "chirp signal") into the motor torque and using FFT (Fast Fourier Transform) analysis, the resonant frequency and anti-resonant frequency of the torque signal are calculated, thereby obtaining the elastic coefficient of the suspension system.

[0048] Similarly, observations obtained offline can be input into the sliding mode observer to obtain torque compensation values ​​for active damping control.

[0049] The damping control method for vehicle transmission systems according to the present invention can achieve at least one of the following advantages:

[0050] - Adopting an adaptive sliding mode observer and parameter identification model reduces the manual calibration process and ensures the robustness of damping control;

[0051] - The parameter identification model can obtain the parameters required by the observer in an online or offline manner, making it suitable for a wider range of application scenarios;

[0052] - Online observation methods utilize the minimum variance evaluation function for online parameter identification, ensuring system stability; and

[0053] Even when vibration frequency shifts due to wear in the vehicle's transmission system, the active damping effect can be corrected in time, preventing vibration suppression from failing.

[0054] Those skilled in the art will understand that the steps of the damping control method for the vehicle transmission system according to the present invention are not limited to being implemented in the order listed above. The method according to the present invention aims to determine the torque compensation value for damping control by means of online or offline observation. As for the order of the steps, such as the order of the execution steps in the parameter identification model, it does not constitute a limitation of the present invention.

[0055] Furthermore, the system disclosed in this invention can be implemented in other ways. The above-described implementation methods are merely illustrative. For example, the division of modules is only for logical functional division, and in actual implementation, there may be other division methods. For example, the functions of multiple modules can be combined, or the function of a certain module can be further split. In the various embodiments of this invention, each module can be integrated into a processing unit, or each module can exist physically separately.

[0056] While the present invention has been disclosed above with reference to preferred embodiments, it is not limited thereto. Any modifications and alterations made by those skilled in the art without departing from the spirit and scope of the invention should be included within the scope of protection of the invention. Therefore, the scope of protection of the invention should be determined by the scope defined in the claims.

Claims

1. A damping control method for a vehicle transmission system, wherein, The method includes the following steps: The first step is to obtain the operating parameters of the vehicle's transmission system; The second step is to input the operating parameters obtained in the first step into the parameter identification model in order to determine the corresponding suspension system parameters. The third step is to input the suspension system parameters determined in the second step into the sliding mode observer to obtain the load torque observation value and shaft torsion observation value. as well as The fourth step involves applying damping control to the vehicle's drivetrain based on the load torque and shaft torque observations obtained in the third step, in order to eliminate speed fluctuations in the motor or wheels. The operating parameters include at least one of the following: motor torque, motor reducer moment of inertia, and actual rotational speed of the motor or wheels. The parameter identification model stores a minimum variance evaluation function between the estimated and actual rotational speeds of the motor or wheels. The model then uses this minimum variance evaluation function to start or stop the parameter identification process. The method also includes: The load torque observations obtained in the third step are fed back into the parameter identification model, and the parameter identification model determines the estimated speed of the motor or wheel based on the received load torque observations, motor torque, and motor reducer rotational inertia.

2. The method according to claim 1, wherein, The parameter identification model uses autoregressive least squares to determine the estimated rotational speed of the motor or wheel.

3. The method according to claim 1 or 2, wherein, The method also includes a fifth step between the third and fourth steps, in which a high-pass filter is used to filter out the DC component in the shaft torsion observation and the phase of the filtered shaft torsion observation is adjusted to obtain a shaft torsion compensation value for compensating for half-shaft undulation torque.

4. The method according to claim 1 or 2, wherein, The suspension system parameters include the elasticity coefficient and the load inertia.

5. A damping control method for a vehicle transmission system, wherein, The method includes the following steps: The first step is to obtain the operating parameters of the vehicle's transmission system; The second step is to input the operating parameters obtained in the first step into the parameter identification model in order to determine the corresponding suspension system parameters. The third step is to input the suspension system parameters determined in the second step into the sliding mode observer to obtain the load torque observation value and shaft torsion observation value. as well as The fourth step involves applying damping control to the vehicle's drivetrain based on the load torque and shaft torque observations obtained in the third step, in order to eliminate speed fluctuations in the motor or wheels. The operating parameters include at least one of the following: motor torque, motor reducer moment of inertia, and actual rotational speed of the motor or wheels. The parameter identification model stores a minimum variance evaluation function between the estimated and actual rotational speeds of the motor or wheels. The model then uses this minimum variance evaluation function to start or stop the parameter identification process. The suspension system parameters include the elastic coefficient and the load inertia. The parameter identification model is also configured to acquire the suspension system parameters offline. In this offline mode, the load inertia is acquired by using a lift to raise the vehicle and adopting closed-loop speed control and a motor mechanical model. The elastic coefficient is acquired by using a linear frequency-modulated torque signal and a fast Fourier transform.

6. A mechanism for damping control of a vehicle transmission system using the method according to any one of claims 1 to 5, wherein, This organization includes: A detection device configured to acquire operating parameters of a vehicle's transmission system; A parameter identification module is configured to determine the corresponding suspension system parameters based on the operating parameters detected by the detection device. A sliding mode observer configured to acquire load torque and shaft torsion observations based on suspension system parameters determined by the parameter identification module; and A control module configured to perform damping control on the vehicle drive system based on load torque observations and shaft torque observations obtained by the sliding mode observer, in order to eliminate speed fluctuations of the motor or wheels.

7. A vehicle powertrain including the mechanism according to claim 6.

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