A method for determining the torque of a commercial vehicle drive anti-slip motor based on slope partitioning

Abstract

The application discloses a kind of based on slope partitioning commercial vehicle drive anti-skid motor torque determination method, it is related to vehicle drive anti-skid control field, it includes the following steps: real-time calculation obtains ground driving force;Obtain ground driving force variation slope, and extract the maximum value of ground driving force in rolling window;Driving axle operating state is divided into non-slip zone, target slip zone and excessive slip zone;Based on the slip state of driving axle, the maximum value of ground driving force allowed by current road surface is determined, and then the required torque of driving axle motor is obtained by inverse calculation in combination with vehicle transmission relationship.The application realizes the determination of driving axle slip state by analyzing the variation slope of ground driving force, thereby avoiding the dependence on vertical load information which is difficult to obtain directly;The application determines the torque of driving axle motor in real time according to different slip states, realizes the effective identification of driving axle slip state and the reasonable determination of motor torque, effectively improves the driving performance of vehicle on low adhesion road surface.

Description

Technical Field

[0001] This invention relates to the field of vehicle drive anti-skid control, and specifically to a method for determining the torque of a commercial vehicle drive anti-skid motor based on slope partitioning. Background Technology

[0002] When starting and accelerating on low-traction surfaces, electric commercial vehicles are prone to excessive drive axle slippage, leading to a decrease in drive force utilization and consequently affecting vehicle driving performance and even driving safety. Therefore, effectively identifying drive axle slippage and determining appropriate drive torque is one of the important technical means to improve the driving performance of commercial vehicles.

[0003] Chinese invention patent CN121084390A proposes a method, system, and device for anti-skid control of electric vehicles based on road surface recognition. This method achieves rational distribution of driving torque through vehicle dynamics modeling, road surface adhesion recognition, and slippage state monitoring, thereby improving driving force utilization and driving stability. However, existing solutions have several limitations in commercial vehicle applications, such as: vertical force is difficult to obtain directly; complex load transfer reduces the accuracy of road surface recognition and control; and the typical road surface database has limited coverage, making it difficult to meet the needs of all operating conditions.

[0004] Chinese invention patent CN121084397A proposes a method, system, device, and medium for anti-slip control of dual-electric-drive axle commercial vehicles. This method calculates the baseline rolling radius and real-time rolling radius using vehicle state information to obtain the real-time slip ratio, and then determines the target torque accordingly to achieve anti-slip control. Existing solutions rely on vertical loads, but the vertical loads of some commercial vehicles are difficult to obtain, and the load variation between empty and fully loaded states is significant, limiting the determination of the target torque and affecting the effectiveness of anti-slip control. Summary of the Invention

[0005] To address the aforementioned shortcomings in the prior art, this invention provides a method for determining the torque of a commercial vehicle drive anti-skid motor based on slope partitioning. This method solves the problem in the prior art where the target torque is limited and the anti-skid control effect is affected by the use of vertical load information for anti-skid control in commercial vehicles.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows: A method for determining the torque of a commercial vehicle drive anti-slip motor based on slope partitioning is provided, which includes the following steps: The ground driving force is calculated in real time based on the motor output torque, motor speed and vehicle inherent parameters; Continuous ground driving force data are obtained using the rolling window method. A linear fit is performed on the data within the window to obtain the slope of the ground driving force change, and the maximum value of the ground driving force within the rolling window is extracted. Set upper and lower limit thresholds for the slope of ground driving force change, and divide the driving axle operating state into non-slip zone, target slip zone and excessive slip zone according to the set thresholds; The maximum allowable ground driving force of the current road surface is determined based on the slip state of the drive axle; when the drive axle is in the non-slip zone or the excessive slip zone, the maximum allowable ground driving force of the current road surface is determined by the maximum effective torque estimation method; when the drive axle is in the target slip zone, the maximum ground driving force within the rolling window is used as the maximum allowable ground driving force of the current road surface. Based on the maximum permissible ground driving force on the current road surface, the required torque of the drive axle motor is calculated by combining the vehicle transmission relationship.

[0007] Furthermore, the expression for calculating the ground driving force is:

[0008] Where F is the calculated ground driving force; T is the motor output torque; This refers to the overall transmission ratio of the transmission system. For transmission efficiency; The moment of inertia of the power transmission system is equivalent to that at the wheel end; The motor speed is equivalent to the angular acceleration at the wheel end; This is the wheel's rolling radius.

[0009] Furthermore, the specific method for obtaining continuous ground driving force data using the rolling window method is as follows: Within each rolling time window, N ground driving force sampling values ​​are selected to construct a ground driving force data sequence for the corresponding time window and denoted as [missing information]. , where F is the calculated ground driving force, i.e. the ground driving force sample value; n is the sample data sequence number.

[0010] Furthermore, the expression for a linear fit is:

[0011] in The real-time slope of a linear fit; This refers to the motor speed; denoted as vehicle speed; b is the coefficient of the linear term.

[0012] Furthermore, specific methods for setting the upper and lower limit thresholds for the slope of the ground driving force change include: Based on the optimal slip ratio distribution in the μ-λ curves of different road surfaces and engineering experience, upper and lower thresholds for the slope of the change in ground driving force are set; where μ represents the adhesion coefficient and λ represents the slip ratio.

[0013] Furthermore, the specific method for dividing the drive axle operating state into the non-slip zone, the target slip zone, and the over-slip zone based on the set thresholds is as follows: When the real-time slope is greater than the upper limit threshold, the drive axle is determined to be in the non-slip zone; When the real-time slope is less than the lower threshold, the drive axle is determined to be in the excessive slip zone. When the real-time slope is between the lower and upper thresholds, the drive axle is determined to be in the target slip zone.

[0014] Furthermore, the specific methods for determining the maximum permissible ground driving force of the current road surface using the maximum effective torque estimation method include: The relaxation factor is determined based on the vehicle's acceleration and the motor's rotational speed, which are equivalent to the angular acceleration at the wheel end. Based on the maximum effective torque estimation theory and relaxation factor, the maximum driving force that the ground can provide is estimated by using the maximum ground driving force within the rolling window, thus obtaining the maximum allowable ground driving force of the current road surface.

[0015] Furthermore, the expression for calculating the relaxation factor is:

[0016] in It is a relaxation factor; The acceleration of the vehicle; The motor speed is the equivalent angular acceleration at the wheel end.

[0017] Furthermore, the expression for estimating the maximum driving force that the ground can provide using the maximum ground driving force within the scrolling window is as follows:

[0018] in This represents the maximum permissible ground driving force on the current road surface. M represents the rotational inertia of the powertrain system equivalent to the wheel ends; M represents the total vehicle mass. The radius of the wheel's rolling radius; This represents the maximum ground driving force within the scrolling window.

[0019] Furthermore, the expression for calculating the required torque of the drive axle motor is as follows:

[0020] in This is the required torque for the drive axle motor; This represents the maximum permissible ground driving force on the current road surface. The radius of the wheel's rolling radius; The moment of inertia of the power transmission system is equivalent to that at the wheel end; The motor speed is equivalent to the angular acceleration at the wheel end; This refers to the overall transmission ratio of the transmission system. For transmission efficiency.

[0021] The beneficial effects of this invention are as follows: This invention analyzes the slope of the change in ground driving force to determine the slip state of the drive axle, thereby avoiding reliance on vertical load information that is difficult to obtain directly; at the same time, this invention divides the slip state of the drive axle into three categories and determines the drive axle motor torque in real time according to different slip states, realizing the effective identification of the slip state of the drive axle and the reasonable determination of the motor torque, effectively improving the driving performance of the vehicle on low-friction surfaces. Attached Figure Description

[0022] Figure 1 This is a flowchart illustrating the method. Figure 2 This is a schematic diagram illustrating the upper and lower limits of the slope and the division of the slip state; Figure 3 A real-time data analysis diagram of ground driving force; Figure 4 The simulation curve is shown in Example 2; Figure 5 The simulation curve is shown in Example 3. Detailed Implementation

[0023] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0024] Example 1: like Figure 1 As shown, the method for determining the torque of a commercial vehicle drive anti-slip motor based on slope partitioning includes the following steps: S1. The ground driving force is calculated in real time based on the motor output torque, motor speed and vehicle inherent parameters; S2. Use the rolling window method to obtain continuous ground driving force data, perform a linear fit on the data within the window to obtain the slope of the ground driving force change, and extract the maximum value of the ground driving force within the rolling window. S3. Set the upper and lower limit thresholds for the slope of the change in ground driving force, and divide the driving axle operating state into the non-slip zone, the target slip zone, and the excessive slip zone according to the set thresholds. S4. Determine the maximum allowable ground driving force of the current road surface based on the slip state of the drive axle; wherein when the drive axle is in the non-slip zone or the excessive slip zone, the maximum allowable ground driving force of the current road surface is determined by the maximum effective torque estimation method; when the drive axle is in the target slip zone, the maximum ground driving force within the rolling window is used as the maximum allowable ground driving force of the current road surface. S5. Based on the maximum allowable ground driving force of the current road surface, the required torque of the drive axle motor is calculated in reverse by combining the vehicle transmission relationship.

[0025] For example, the expression for calculating the ground driving force is:

[0026] Where F is the calculated ground driving force; T is the motor output torque; This refers to the overall transmission ratio of the transmission system. For transmission efficiency; The moment of inertia of the power transmission system is equivalent to that at the wheel end; The motor speed is equivalent to the angular acceleration at the wheel end; This is the wheel's rolling radius.

[0027] For example, the specific method for obtaining continuous ground driving force data using the rolling window method is as follows: Within each rolling time window, N ground driving force sampling values ​​are selected to construct a ground driving force data sequence for the corresponding time window and denoted as [missing information]. , where F is the calculated ground driving force, i.e. the ground driving force sample value; n is the sample data sequence number.

[0028] The expression for a linear fit is:

[0029] in The real-time slope of a linear fit; This refers to the motor speed; denoted as vehicle speed; b is the coefficient of the linear term.

[0030] In this embodiment, as Figure 2 As shown, the specific methods for setting the upper and lower limit thresholds of the slope of the ground driving force change include: Based on the optimal slip ratio distribution in the μ-λ curves of different road surfaces and engineering experience, an upper limit threshold for the slope of the change in ground driving force is set. With lower threshold Where μ represents the adhesion coefficient and λ represents the slip ratio.

[0031] For example, the specific method for dividing the driving axle operating state into a non-slip zone, a target slip zone, and an over-slip zone based on a set threshold is as follows: When the real-time slope is greater than the upper limit threshold, the drive axle is determined to be in the non-slip zone; When the real-time slope is less than the lower threshold, the drive axle is determined to be in the excessive slip zone. When the real-time slope is between the lower and upper thresholds, the drive axle is determined to be in the target slip zone.

[0032] In practical implementation, the specific methods for determining the maximum allowable ground driving force of the current road surface using the maximum effective torque estimation method include: The relaxation factor is determined based on the vehicle's acceleration and the motor's rotational speed, which are equivalent to the angular acceleration at the wheel end. Based on the maximum effective torque estimation theory and relaxation factor, the maximum driving force that the ground can provide is estimated by using the maximum ground driving force within the rolling window, thus obtaining the maximum allowable ground driving force of the current road surface.

[0033] For example, the expression for calculating the relaxation factor is:

[0034] in It is a relaxation factor; The acceleration of the vehicle; The motor speed is the equivalent angular acceleration at the wheel end.

[0035] The expression for estimating the maximum driving force that the ground can provide using the maximum ground driving force within the scrolling window is as follows:

[0036] in This represents the maximum permissible ground driving force on the current road surface. M represents the rotational inertia of the powertrain system equivalent to the wheel ends; M represents the total vehicle mass. The radius of the wheel's rolling radius; This represents the maximum ground driving force within the scrolling window.

[0037] The expression for calculating the required torque of the drive axle motor is:

[0038] in This is the required torque for the drive axle motor; This represents the maximum permissible ground driving force on the current road surface. The radius of the wheel's rolling radius; The moment of inertia of the power transmission system is equivalent to that at the wheel end; The motor speed is equivalent to the angular acceleration at the wheel end; This refers to the overall transmission ratio of the transmission system. For transmission efficiency.

[0039] In this embodiment, a pure electric commercial vehicle is used as the controlled object, with the load in an unloaded state. The road surface condition is set as a pure low-adhesion road surface with a road adhesion coefficient of 0.15. The vehicle starts from a standstill, and the pedal opening slowly increases from 0 to 30%. The ground driving force is obtained in real time using the rolling window method as follows: Figure 3 As shown, by Figure 3 It can be seen that the slope of the curve fitted to the real-time values ​​in region A is greater than the upper threshold. The majority of points in this region fall within the non-slip zone. The maximum ground driving force here is calculated based on the maximum effective torque estimation theory. The slope of the curve fitted by the real-time values ​​in region C is less than the lower threshold. The majority of points in this region fall within the excessive slip zone. The maximum ground driving force here is calculated based on the maximum effective torque estimation theory. The slope of the curve fitted to the real-time values ​​in region B is within the upper threshold. With lower threshold Between these points, the maximum ground driving force within the scrolling window is used as the current maximum ground driving force on the road surface. Most points in this area fall within the target slip zone. This demonstrates that this method can theoretically effectively identify the slip state of the drive axle and reasonably determine the maximum ground driving force, thereby calculating the motor torque and achieving anti-slip control.

[0040] Example 2: This embodiment is a further extension based on Embodiment 1. This embodiment simulates the results of full-throttle acceleration on a road surface with a coefficient of adhesion of 0.2, as shown below. Figure 4 As shown, this method can quickly identify and suppress initial slippage, rapidly converging the slippage rate of both drive wheels from a peak of approximately 0.6 and stabilizing it within the ideal range of approximately 0.1. Simultaneously, through dynamic torque distribution between the axles and motor torque adjustment, it ensures smooth power output while suppressing slippage, keeping the drive wheel speed essentially consistent with the half-vehicle speed. The longitudinal acceleration stabilizes at approximately 0.6 m / s² after the initial fluctuation. Overall, it achieves efficient slippage suppression, smooth acceleration, and stable driving on low-adhesion road surfaces, improving driving safety. (Figure...) and These are the torque of the front axle motor and the torque of the rear axle motor, respectively. and These are the front axle slip ratio and the rear axle slip ratio, respectively. and These are the front axle wheel speed and the rear axle wheel speed, respectively, and r is the wheel rolling radius.

[0041] Example 3: This embodiment is a further extension based on Embodiment 1. This embodiment simulates a transition from a road surface with a coefficient of adhesion of 0.5 to a surface with a coefficient of adhesion of 0.2, and the results of full-throttle acceleration are as follows. Figure 5 As shown, the motor torque rapidly decreased after the initial peak and stabilized in a steady state, effectively suppressing excessive wheel slippage. The slip ratio of both drive wheels quickly dropped from its initial high and stabilized within a reasonable range without significant oscillations. The vehicle speed and drive wheel speed curves closely matched, with no significant speed difference. The longitudinal acceleration remained stable after an initial slight fluctuation, achieving the comprehensive control objectives of precise slippage suppression, smooth power output, and efficient acceleration on low-adhesion surfaces. (See figure) and These are the torque of the front axle motor and the torque of the rear axle motor, respectively. and These are the front axle slip ratio and the rear axle slip ratio, respectively. and These are the front axle wheel speed and the rear axle wheel speed, respectively, and r is the wheel rolling radius.

[0042] In summary, this invention classifies drive axle slip states by analyzing the slope of ground driving force changes and setting upper and lower thresholds for the slope. For different slip states, corresponding methods are used to obtain the maximum ground driving force, from which the required motor torque is deduced. This invention does not rely on vertical load information, which is difficult to obtain directly, achieving accurate identification of drive axle slip states and reasonable determination of motor torque, effectively improving vehicle driving performance on low-traction surfaces.

Claims

1. A method for determining the torque of a commercial vehicle drive anti-slip motor based on slope partitioning, characterized in that, Includes the following steps: The ground driving force is calculated in real time based on the motor output torque, motor speed and vehicle inherent parameters; Continuous ground driving force data are obtained using the rolling window method. A linear fit is performed on the data within the window to obtain the slope of the ground driving force change, and the maximum value of the ground driving force within the rolling window is extracted. Set upper and lower limit thresholds for the slope of ground driving force change, and divide the driving axle operating state into non-slip zone, target slip zone and excessive slip zone according to the set thresholds; The maximum allowable ground driving force of the current road surface is determined based on the slip state of the drive axle; when the drive axle is in the non-slip zone or the excessive slip zone, the maximum allowable ground driving force of the current road surface is determined by the maximum effective torque estimation method. When the drive axle is in the target slip zone, the maximum ground driving force within the rolling window is used as the maximum allowable ground driving force for the current road surface. Based on the maximum permissible ground driving force on the current road surface, the required torque of the drive axle motor is calculated by combining the vehicle transmission relationship.

2. The method for determining the torque of a commercial vehicle drive anti-slip motor based on slope partitioning according to claim 1, characterized in that, The expression for calculating ground driving force is: Where F is the calculated ground driving force; T is the motor output torque; This refers to the overall transmission ratio of the transmission system. For transmission efficiency; The moment of inertia of the power transmission system is equivalent to that at the wheel end; The motor speed is equivalent to the angular acceleration at the wheel end; This is the rolling radius of the wheel.

3. The method for determining the torque of a commercial vehicle drive anti-slip motor based on slope partitioning according to claim 1, characterized in that, The specific method for obtaining continuous ground driving force data using the rolling window method is as follows: Within each rolling time window, N ground driving force sampling values ​​are selected to construct a ground driving force data sequence for the corresponding time window and denoted as [missing information]. , where F is the calculated ground driving force, i.e. the ground driving force sample value; n is the sample data sequence number.

4. The method for determining the torque of a commercial vehicle drive anti-slip motor based on slope partitioning according to claim 1, characterized in that, The expression for a linear fit is: in The real-time slope of a linear fit; This refers to the motor speed; denoted as vehicle speed; b is the coefficient of the linear term.

5. The method for determining the torque of a commercial vehicle drive anti-slip motor based on slope partitioning according to claim 4, characterized in that, Specific methods for setting the upper and lower limit thresholds for the slope of ground driving force change include: Based on the optimal slip ratio distribution in the μ-λ curves of different road surfaces and engineering experience, upper and lower thresholds for the slope of the change in ground driving force are set; where μ represents the adhesion coefficient and λ represents the slip ratio.

6. The method for determining the torque of a commercial vehicle drive anti-slip motor based on slope partitioning according to claim 5, characterized in that, The specific method for dividing the drive axle operating state into the non-slip zone, target slip zone, and over-slip zone based on the set thresholds is as follows: When the real-time slope is greater than the upper limit threshold, the drive axle is determined to be in the non-slip zone; When the real-time slope is less than the lower threshold, the drive axle is determined to be in the excessive slip zone. When the real-time slope is between the lower and upper thresholds, the drive axle is determined to be in the target slip zone.

7. The method for determining the torque of a commercial vehicle drive anti-slip motor based on slope partitioning according to claim 1, characterized in that, The specific methods for determining the maximum allowable ground driving force of the current road surface using the maximum effective torque estimation method include: The relaxation factor is determined based on the vehicle's acceleration and the motor's rotational speed, which are equivalent to the angular acceleration at the wheel end. Based on the maximum effective torque estimation theory and relaxation factor, the maximum driving force that the ground can provide is estimated by using the maximum ground driving force within the rolling window, thus obtaining the maximum allowable ground driving force of the current road surface.

8. The method for determining the torque of a commercial vehicle drive anti-slip motor based on slope partitioning according to claim 7, characterized in that, The expression for calculating the relaxation factor is: in It is a relaxation factor; The acceleration of the vehicle; This is the angular acceleration at the wheel end, which is equivalent to the motor speed.

9. The method for determining the torque of a commercial vehicle drive anti-slip motor based on slope partitioning according to claim 8, characterized in that, The expression for estimating the maximum driving force that the ground can provide using the maximum ground driving force within the scrolling window is as follows: in This represents the maximum permissible ground driving force on the current road surface. The moment of inertia of the power transmission system is equivalent to that at the wheel end; M represents the vehicle mass; The radius of the wheel's rolling radius; This represents the maximum ground driving force within the scrolling window.

10. The method for determining the torque of a commercial vehicle drive anti-slip motor based on slope partitioning according to claim 1, characterized in that, The expression for calculating the required torque of the drive axle motor is: in This is the required torque for the drive axle motor; This represents the maximum permissible ground driving force on the current road surface. The radius of the wheel's rolling radius; The moment of inertia of the power transmission system is equivalent to that at the wheel end; The motor speed is equivalent to the angular acceleration at the wheel end; This refers to the overall transmission ratio of the transmission system. For transmission efficiency.

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