Distributed torque distribution method and device of vehicle, vehicle and storage medium

Abstract

The application provides a distributed torque distribution method and device of a vehicle, the vehicle and a storage medium. The method comprises: identifying a current steering working condition of the vehicle during distributed driving of the vehicle in a four-wheel drive mode; acquiring an actual yaw angular velocity of the vehicle and determining a torque distribution mode of the vehicle according to a speed difference or a speed change rate between the actual yaw angular velocity and a target yaw angular velocity when the current steering working condition is an understeering working condition or an oversteering working condition; and calculating target torque of at least one drive shaft or at least one drive wheel of the vehicle in the understeering working condition or the oversteering working condition based on the torque distribution mode. The method can distribute torque according to the change of the yaw angular velocity of the vehicle, calculate the driving torque in different working conditions, and thus actively reduce or increase the yaw torque to improve the understeering or oversteering condition and improve the steering stability of the vehicle.

Description

Technical Field

[0001] This application relates to the field of vehicle power drive, and more specifically, to a method, apparatus, vehicle, and storage medium for distributed torque distribution of a vehicle. Background Technology

[0002] Currently, vehicles with four wheels driven separately in the industry are either in the concept car stage or in an immature stage, and the torque distribution between the front, rear, left, and right wheels in curves is still being explored and matched.

[0003] In related technologies, when a vehicle exhibits significant understeer or oversteer, the degree of understeer or rear drive shaft sideslip can be determined by the magnitude of the change in yaw rate. This allows for the determination of the target front and rear drive shaft torque distribution ratio. By modifying the front and rear drive torque distribution ratio, the magnitude of the yaw torque can be altered, thereby modifying the vehicle's yaw rate. This reduces the risk of understeer or fishtailing and improves vehicle handling stability.

[0004] However, when redistributing torque under understeer or oversteer conditions, the relevant technologies cannot reasonably distribute the excess torque and cannot make accurate adjustments according to the vehicle condition. This makes it difficult to effectively deal with understeer or oversteer conditions, thus affecting the vehicle's steering stability and even easily leading to serious traffic accidents, which urgently needs to be addressed. Summary of the Invention

[0005] This application provides a distributed torque distribution method, device, vehicle, and storage medium for a vehicle. The method can distribute torque according to the change of the vehicle's yaw rate to calculate the driving torque under different operating conditions, thereby actively reducing or increasing the yaw torque to improve understeer or oversteer, enhance vehicle steering stability, and effectively ensure vehicle safety.

[0006] Firstly, a distributed torque distribution method for a vehicle is provided, the method comprising:

[0007] When the vehicle is in four-wheel drive mode with distributed drive, the current steering condition of the vehicle is identified.

[0008] When the current steering condition is understeer or oversteer, the actual yaw rate of the vehicle is obtained, and the torque distribution mode of the vehicle is determined based on the speed value of the actual yaw rate, the speed difference between the actual yaw rate and the target yaw rate, or the speed change rate.

[0009] Based on the torque distribution mode, the target torque of at least one drive axle or at least one drive wheel of the vehicle is calculated under the understeer condition or the oversteer condition.

[0010] The above technical solution can determine the torque distribution mode based on the change of vehicle yaw rate, so as to calculate the target torque under different operating conditions, thereby actively reducing or increasing yaw torque to improve understeer or oversteer conditions and improve vehicle steering stability.

[0011] In conjunction with the first aspect, some possible implementations also include:

[0012] Determine whether the target torque of the at least one drive shaft is greater than the corresponding first maximum limit torque;

[0013] If the torque exceeds the corresponding first maximum limit torque, the corresponding drive shaft output is controlled by the first maximum limit torque. A first excess torque is obtained based on the target torque and the first maximum limit torque. The first excess torque is then attenuated by a first preset attenuation ratio to obtain a first attenuated torque. The first attenuated torque is then transferred to another drive shaft other than the corresponding drive shaft for output.

[0014] The above technical solution can reduce the excess torque by a certain proportion before transferring it when the target torque of the drive shaft exceeds the first maximum limit torque. This can ensure that the steering characteristics are changed and avoid the problem of rapid torque reduction caused by complete attenuation.

[0015] In conjunction with the first aspect, some possible implementations also include:

[0016] Determine whether the target torque of the at least one drive wheel is greater than the corresponding second maximum limit torque;

[0017] If the torque exceeds the corresponding second maximum limit torque, the output of the corresponding drive wheel is controlled by the second maximum limit torque. A second excess torque is obtained based on the target torque and the second maximum limit torque. The second excess torque is then attenuated by a second preset attenuation ratio to obtain a second attenuated torque. The second attenuated torque is then transferred to the output torque of another drive wheel coaxial with the corresponding drive wheel.

[0018] The above technical solution can reduce the excess torque by a certain proportion before transferring it when the target torque of the drive wheel exceeds the second maximum limit torque. This can ensure that the steering characteristics are changed and avoid the problem of rapid torque reduction caused by complete attenuation.

[0019] In conjunction with the first aspect, in some possible implementations, determining the vehicle's torque distribution mode based on the actual yaw rate, the speed difference between the actual yaw rate and the target yaw rate, or the rate of change of speed includes:

[0020] Obtain the yaw moment of the vehicle;

[0021] When the yaw moment is greater than a first preset threshold, the torque distribution mode is an inter-axis active torque distribution mode.

[0022] If the absolute value of the difference between the actual rate of change of yaw rate and the target rate of change of yaw rate is greater than a second preset threshold, the torque distribution mode is the inter-wheel active torque distribution feedforward adjustment mode.

[0023] When the absolute value of the difference between the target yaw rate and the actual yaw rate is greater than a third preset threshold, the torque distribution mode is the inter-wheel torque distribution feedback adjustment mode.

[0024] The above technical solution can determine the torque distribution mode based on the yaw moment, the target yaw rate, the difference between the rate of change of the actual yaw rate and the rate of change of the target yaw rate, and the difference between the target yaw rate and the actual yaw rate. This allows for feedforward and feedback torque distribution based on changes in yaw rate, enabling the torque distribution to be tailored to various steering conditions of the vehicle.

[0025] In conjunction with the first aspect, in some possible implementations, calculating the target torque of at least one drive axle or at least one drive wheel of the vehicle under the understeer condition or the oversteer condition, based on the torque distribution mode, includes:

[0026] If the torque distribution mode is the inter-axle active torque distribution mode, then a first threshold value of the yaw moment is determined based on the actual road adhesion coefficient, the current rear axle slip angle of the vehicle and the current driving mode, and the first threshold value is used to determine whether the inter-axle active torque distribution mode meets the first preset activation condition, so as to determine the target torque of the at least one drive axle when the inter-axle active torque distribution mode meets the first preset activation condition.

[0027] If the torque distribution mode is the inter-wheel active torque distribution feedforward adjustment mode, then based on the actual road adhesion coefficient, the actual vehicle speed, the current steering wheel angle, the current rear axle slip angle, and the second threshold value of the vehicle emergency factor, and using the second threshold value, it is determined whether the inter-wheel active torque distribution feedforward adjustment mode meets the second preset activation condition, so that when the inter-wheel active torque distribution feedforward adjustment mode meets the second preset activation condition, the target torque of the at least one drive wheel is determined;

[0028] If the torque distribution mode is the inter-wheel torque distribution feedback adjustment mode, then based on the actual road adhesion coefficient, the actual vehicle speed, the current steering wheel angle, the current rear axle slip angle, and the third threshold value of the vehicle emergency factor, and using the third threshold value, it is determined whether the inter-wheel torque distribution feedback adjustment mode meets the third preset activation condition, so that when the inter-wheel torque distribution feedback adjustment mode meets the third preset activation condition, the target torque of the at least one drive wheel is determined.

[0029] The above technical solution can determine the corresponding correction coefficient according to the torque distribution mode to correct the yaw torque of the drive shaft or drive wheel, so that the limiting torque determined based on the yaw torque can meet the current steering conditions of the vehicle and ensure the steering stability of the vehicle.

[0030] In conjunction with the first aspect, in some possible implementations, determining the target torque of the at least one drive shaft or at least one drive wheel includes:

[0031] Determine the basic torque distribution ratio of the rear drive shaft in the at least one drive shaft;

[0032] The basic change ratio of the rear drive shaft is obtained based on the yaw rate difference of the vehicle.

[0033] The rear drive shaft variation ratio is obtained based on the actual vehicle speed and the actual road adhesion coefficient.

[0034] The current demand allocation ratio of the rear drive shaft is obtained by subtracting the rear drive shaft change ratio from the basic allocation ratio.

[0035] The target torque of the rear drive shaft is obtained by multiplying the total torque of the vehicle by the demand distribution ratio of the rear drive shaft.

[0036] The original target torque of the drive wheel is obtained based on the current torque difference between the left drive wheel and the right drive wheel in at least one drive wheel;

[0037] The actual torque difference of the drive wheels is obtained based on the target yaw moment of the vehicle, and the target torques of the left and right drive wheels are obtained based on the actual torque difference and the original target torque.

[0038] The above technical solution can obtain the actual torque difference of the drive wheels based on the target yaw moment, and obtain the target torque of the left and right drive wheels from the original target torque of the drive wheels after shaft distribution and the actual torque difference of the drive wheels.

[0039] In conjunction with the first aspect, in some possible implementations, the emergency factor is obtained from at least one of the vehicle's yaw moment, actual vehicle speed and driving mode, and the road surface adhesion coefficient of the current road.

[0040] Through the above technical solution, the factor can be obtained from a variety of data, making the value of the torque change of the rear drive shaft determined based on the factor more accurate.

[0041] Secondly, a distributed torque distribution device for a vehicle is provided, the device comprising:

[0042] The identification module is used to identify the vehicle's current steering condition when the vehicle is in four-wheel drive mode with distributed drive.

[0043] The calculation module is used to obtain the actual yaw rate of the vehicle when the current steering condition is understeering or oversteering, and to determine the torque distribution mode of the vehicle based on the speed value of the actual yaw rate, the speed difference between the actual yaw rate and the target yaw rate, or the speed change rate.

[0044] The distribution module is used to calculate, based on the torque distribution mode, the target torque of at least one drive shaft or at least one drive wheel of the vehicle under the understeer condition or the oversteer condition.

[0045] In combination with the second aspect and the above implementation methods, some possible implementation methods also include:

[0046] The first judgment module is used to determine whether the target torque of the at least one drive shaft is greater than the corresponding first maximum limit torque.

[0047] The first output module is configured to control the output of the corresponding drive shaft at the first maximum limit torque when the torque exceeds the corresponding first maximum limit torque, obtain a first excess torque based on the target torque and the first maximum limit torque, attenuate the first excess torque by a first preset attenuation ratio to obtain a first attenuated torque, and transfer the first attenuated torque to another drive shaft other than the corresponding drive shaft for output.

[0048] In combination with the second aspect and the above implementation methods, some possible implementation methods also include:

[0049] The second judgment module is used to determine whether the target torque of the at least one drive wheel is greater than the corresponding second maximum limit torque.

[0050] The second output module is used to control the output of the corresponding drive wheel when the torque exceeds the corresponding second maximum limit torque, and to obtain a second excess torque based on the target torque and the second maximum limit torque, and to attenuate the second excess torque by a second preset attenuation ratio to obtain a second attenuated torque, and to transfer the second attenuated torque to the output torque of another drive wheel coaxial with the corresponding drive wheel.

[0051] In combination with the second aspect and the above implementation methods, in some possible implementations, the computing module includes:

[0052] Acquisition unit, used to acquire the yaw moment of the vehicle;

[0053] The first calculation unit is configured to, when the yaw moment is greater than a first preset threshold, use an inter-axis active torque distribution mode for the torque distribution mode.

[0054] The second calculation unit is used to set the torque distribution mode as the wheel-to-wheel active torque distribution feedforward adjustment mode when the absolute value of the difference between the actual rate of change of yaw rate and the target rate of change of yaw rate is greater than a second preset threshold.

[0055] The third calculation unit is used to set the torque distribution mode to the inter-wheel torque distribution feedback adjustment mode when the absolute value of the difference between the target yaw rate and the actual yaw rate is greater than a third preset threshold.

[0056] In combination with the second aspect and the above implementation methods, in some possible implementations, the allocation module includes:

[0057] The first judgment unit is used to determine a first threshold value of yaw moment based on the actual adhesion coefficient of the road, the current rear axle slip angle of the vehicle and the current driving mode when the torque distribution mode is the inter-axle active torque distribution mode, and to use the first threshold value to determine whether the inter-axle active torque distribution mode meets the first preset activation condition, so as to determine the target torque of the at least one drive axle when the inter-axle active torque distribution mode meets the first preset activation condition.

[0058] The second judgment unit is used to determine a second threshold value of the difference in yaw rate change rate based on the actual adhesion coefficient of the road, the actual vehicle speed, the current steering wheel angle, the current rear axle slip angle, and the vehicle emergency factor when the torque distribution mode is the inter-wheel active torque distribution feedforward adjustment mode, and to use the second threshold value to determine whether the inter-wheel active torque distribution feedforward adjustment mode meets the second preset activation condition, so as to determine the target torque of the at least one drive wheel when the inter-wheel active torque distribution feedforward adjustment mode meets the second preset activation condition;

[0059] The third judgment unit is used to determine a third threshold value of the yaw rate change difference based on the actual road adhesion coefficient, the actual vehicle speed, the current steering wheel angle, the current rear axle slip angle, and the vehicle emergency factor when the torque distribution mode is the inter-wheel torque distribution feedback adjustment mode, and to use the third threshold value to determine whether the inter-wheel torque distribution feedback adjustment mode meets the third preset activation condition, so as to determine the target torque of the at least one drive wheel when the inter-wheel torque distribution feedback adjustment mode meets the third preset activation condition.

[0060] In combination with the second aspect and the above implementation methods, in some possible implementations, the allocation module is used for:

[0061] Determine the basic torque distribution ratio of the rear drive shaft in the at least one drive shaft;

[0062] The basic change ratio of the rear drive shaft is obtained based on the yaw rate difference of the vehicle.

[0063] The rear drive shaft variation ratio is obtained based on the actual vehicle speed and the actual road adhesion coefficient.

[0064] The current demand allocation ratio of the rear drive shaft is obtained by subtracting the rear drive shaft change ratio from the basic allocation ratio.

[0065] The target torque of the rear drive shaft is obtained by multiplying the total torque of the vehicle by the demand distribution ratio of the rear drive shaft.

[0066] The original target torque of the drive wheel is obtained based on the current torque difference between the left drive wheel and the right drive wheel in at least one drive wheel;

[0067] The actual torque difference of the drive wheels is obtained based on the target yaw moment of the vehicle, and the target torques of the left and right drive wheels are obtained based on the actual torque difference and the original target torque.

[0068] In combination with the second aspect and the above implementation methods, in some possible implementation methods, the emergency factor is obtained from at least one of the vehicle's yaw moment, actual vehicle speed and driving mode, and the road surface adhesion coefficient of the current road.

[0069] Thirdly, a vehicle is provided, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, the processor executing the program to implement the method of the first aspect or any possible implementation thereof.

[0070] Fourthly, a computer-readable storage medium is provided that stores computer program code, which, when executed on a computer, causes the computer to perform the methods described in the first aspect or any possible implementation thereof. Attached Figure Description

[0071] Figure 1 A flowchart illustrating a distributed torque distribution method for a vehicle, provided as an embodiment of this application;

[0072] Figure 2 This is a schematic diagram of the torque distribution process between the shaft end and the wheel end according to one embodiment of this application;

[0073] Figure 3 This is a schematic diagram of the wheelbase drive torque distribution process according to one embodiment of this application;

[0074] Figure 4 This is a schematic diagram of the wheel-end drive torque distribution process according to an embodiment of this application;

[0075] Figure 5 This is a schematic diagram illustrating the distribution process of the inner and outer drive wheels of the rear drive shaft under understeering conditions, according to one embodiment of this application.

[0076] Figure 6 This is a schematic diagram illustrating the process of obtaining the true variation difference of the front drive axle wheel end torque according to an embodiment of this application.

[0077] Figure 7 This is a schematic diagram of the front drive shaft inner and outer drive wheel distribution process according to an embodiment of this application;

[0078] Figure 8 A schematic diagram of the structure of a distributed torque distribution device for a vehicle provided in an embodiment of this application;

[0079] Figure 9 This is a schematic diagram of the vehicle structure provided in an embodiment of this application. Detailed Implementation

[0080] The technical solutions in this application will be clearly and thoroughly described below with reference to the accompanying drawings. In the description of the embodiments of this application, unless otherwise stated, " / " means "or," for example, A / B can mean A or B. "And / or" in the text is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, in the description of the embodiments of this application, "multiple" refers to two or more than two.

[0081] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0082] Figure 1 This is a schematic flowchart of a distributed torque distribution method for a vehicle provided in an embodiment of this application.

[0083] For example, such as Figure 1 As shown, the distributed torque distribution method for this vehicle includes the following steps:

[0084] In step S101, during the process of the vehicle being in four-wheel drive mode distributed drive, the current steering condition of the vehicle is identified.

[0085] In four-wheel drive mode, both the front and rear wheels of the vehicle are driven, and the motor output torque can be distributed to all the front and rear wheels in different proportions according to different road conditions to improve the vehicle's driving ability.

[0086] In this embodiment of the application, when the vehicle is in the distributed drive process of four-wheel drive mode, the current steering condition of the vehicle can be identified by the relevant parameters of the vehicle. For example, this embodiment of the application can obtain the steering angle parameters fed back by the steering wheel angle sensor, the actual yaw rate of the vehicle obtained by the yaw rate sensor, and the current accelerator pedal opening signal of the vehicle obtained by the pedal opening sensor. Based on the above parameters, the current steering condition of the vehicle can be identified. The current steering condition may include normal steering condition, understeer condition, and oversteer condition.

[0087] In step S102, when the current steering condition is understeering or oversteering, the actual yaw rate of the vehicle is obtained, and the torque distribution mode of the vehicle is determined based on the speed value of the actual yaw rate, the speed difference between the actual yaw rate and the target yaw rate, or the speed change rate.

[0088] Understandably, when the steering condition is understeer or oversteer, the vehicle's current torque is insufficient to ensure stable steering. Therefore, torque redistribution is necessary in understeer or oversteer conditions.

[0089] At this point, the embodiments of this application can obtain the actual yaw rate of the vehicle, and determine the torque distribution mode of the vehicle based on the speed value of the actual yaw rate, the speed difference between the actual yaw rate and the target yaw rate, or the speed change rate. The specific determination method is illustrated below.

[0090] Optionally, in one embodiment of this application, determining the vehicle's torque distribution mode based on the actual yaw rate, the speed difference between the actual yaw rate and the target yaw rate, or the rate of change of speed includes: acquiring the vehicle's yaw moment; when the yaw moment is greater than a first preset threshold, the torque distribution mode is an inter-axle active torque distribution mode; when the absolute value of the difference between the actual yaw rate and the target yaw rate is greater than a second preset threshold, the torque distribution mode is an inter-wheel active torque distribution feedforward adjustment mode; and when the absolute value of the difference between the target yaw rate and the actual yaw rate is greater than a third preset threshold, the torque distribution mode is an inter-wheel torque distribution feedback adjustment mode.

[0091] In some embodiments, this application embodiment can determine whether the vehicle enters the four-wheel drive distributed drive mode by using parameters such as vehicle speed, total torque demand, and steering wheel angle, combined with the steering angle after the falling edge function. At this time, the basic torque distribution function is activated. That is to say, when the vehicle speed is greater than a certain value, the total torque demand is greater than a certain value, the steering wheel angle is greater than a certain value, and the falling edge function ensures that the steering angle is less than a certain value for a certain period of time but is still greater than a certain value, the vehicle enters the four-wheel drive distributed drive mode and the basic torque distribution function is activated. The aforementioned certain value can be set by those skilled in the art according to the actual situation, or it can be obtained by referring to a table based on the vehicle speed. The basic torque distribution function window can have a true and false calibration quantity debug window. When the calibration quantity is 0, this application embodiment will not distribute torque and will directly output the distribution value in the mode.

[0092] Furthermore, in this embodiment, when the vehicle yaw moment exceeds a certain set value, the basic torque distribution function is activated, and the torque distribution mode is determined to be the inter-axle active torque distribution mode. Here, the set value, i.e., the first preset threshold, can be obtained by looking up a table based on the reference vehicle speed and corrected using a correction coefficient obtained from looking up the table based on the adhesion coefficient, rear axle slip angle, and driving mode. For example, in this embodiment, the function activation range can be obtained by looking up a table, and the first preset threshold can be the upper limit of the activation range. When the yaw moment exceeds the upper limit, the basic torque distribution function is activated, and the torque distribution mode is determined to be the inter-axle active torque distribution mode. After the above function is activated, the yaw moment must be less than the lower limit to deactivate the function.

[0093] In this embodiment, when the absolute value of the difference between the actual yaw rate change rate and the target yaw rate change rate is greater than a certain set value, and the basic torque distribution function is activated, the torque distribution mode is determined to be the inter-wheel active torque distribution feedforward adjustment mode. Here, the set value, i.e., the second preset threshold, can be looked up in a table with reference to vehicle speed, and corrected according to the adhesion coefficient, vehicle speed, steering wheel angle, rear axle sideslip angle, and vehicle emergency factor obtained from the table.

[0094] In this embodiment, when the absolute value of the difference between the target yaw rate and the actual yaw rate is greater than a certain set value, and the basic torque distribution function is activated, the torque distribution mode is determined to be the inter-wheel active torque distribution feedforward adjustment mode. Here, the set value, i.e., the third preset threshold, can be looked up in a table with reference to vehicle speed, and corrected according to the correction coefficient obtained from looking up the table based on the adhesion coefficient, vehicle speed, steering wheel angle, rear axle sideslip angle, and vehicle emergency factor.

[0095] By activating the corresponding torque distribution mode, this application embodiment can determine when to trigger an active reduction or increase in yaw torque to ensure the stability of vehicle steering.

[0096] In step S103, based on the torque distribution mode, the target torque of at least one drive axle or at least one drive wheel of the vehicle is calculated under the understeer condition or the oversteer condition.

[0097] In actual implementation, the embodiments of this application can calculate the target torque of the drive shaft or drive wheels of the vehicle under different steering conditions based on the corresponding torque distribution mode.

[0098] In other words, the embodiments of this application can calculate the target torque of at least one drive axle of the vehicle under understeer or oversteer conditions in the inter-axle active torque distribution mode; the embodiments of this application can calculate the target torque of at least one drive wheel of the vehicle under understeer or oversteer conditions in the inter-wheel active torque distribution feedforward adjustment mode or the inter-wheel active torque distribution feedforward adjustment mode.

[0099] Optionally, in one embodiment of this application, calculating the target torque of at least one drive axle or at least one drive wheel under understeer or oversteer conditions based on the torque distribution mode includes: if the torque distribution mode is an inter-axle active torque distribution mode, then determining a first threshold value of the yaw moment based on the actual road adhesion coefficient, the vehicle's current rear axle slip angle, and the current driving mode, and using the first threshold value to determine whether the inter-axle active torque distribution mode meets a first preset activation condition, so as to determine the target torque of at least one drive axle when the inter-axle active torque distribution mode meets the first preset activation condition; if the torque distribution mode is an inter-wheel active torque distribution feedforward adjustment mode, then calculating the target torque of at least one drive axle based on the actual road adhesion coefficient, the vehicle's actual speed, the current steering wheel angle, and the current rear axle slip angle. The second threshold value of the difference in yaw rate change is determined by the angle and the vehicle emergency factor. The second threshold value is then used to determine whether the inter-wheel active torque distribution feedforward adjustment mode meets the second preset activation condition. When the inter-wheel active torque distribution feedforward adjustment mode meets the second preset activation condition, the target torque of at least one drive wheel is determined. If the torque distribution mode is the inter-wheel torque distribution feedback adjustment mode, a third threshold value of the difference in yaw rate change is determined based on the actual road adhesion coefficient, the actual vehicle speed, the current steering wheel angle, the current rear axle sideslip angle, and the vehicle emergency factor. The third threshold value is then used to determine whether the inter-wheel torque distribution feedback adjustment mode meets the third preset activation condition. When the inter-wheel torque distribution feedback adjustment mode meets the third preset activation condition, the target torque of at least one drive wheel is determined.

[0100] In actual implementation, the embodiments of this application can perform feedforward and feedback torque distribution according to the change of yaw rate. The following is an explanation of the target torque calculation under different steering conditions, wherein the target torque of the drive shaft is the drive torque of the drive shaft, and the target torque of the drive wheel is the drive torque of the drive wheel.

[0101] When the torque distribution mode is the inter-axle active torque distribution mode, the embodiments of this application can obtain the threshold value corresponding to the inter-axle active torque distribution mode through dynamic parameters such as the actual adhesion coefficient of the road, the current rear axle sideslip angle of the vehicle, and the current driving mode. The threshold value may include the upper limit value and the lower limit value of the yaw moment. Based on the upper limit value, the lower limit value, and the current yaw moment of the vehicle, it is determined whether the inter-axle active torque distribution mode meets the first preset activation condition, and then the axle distribution is determined to be at the on / off threshold. When the inter-axle active torque distribution mode meets the first preset activation condition, the axle distribution is activated and the corresponding function is triggered so that the corresponding torque distribution can be performed subsequently, and finally the target torque of at least one drive axle is determined.

[0102] Similarly, when the torque distribution mode is the inter-wheel active torque distribution feedforward adjustment mode, the embodiments of this application can obtain the threshold value corresponding to the inter-wheel active torque distribution feedforward adjustment mode through dynamic parameters such as the actual road adhesion coefficient, the actual vehicle speed, the current steering wheel angle, the current rear axle sideslip angle, and the vehicle emergency factor. The threshold value may include an upper limit value and a lower limit value of the yaw rate change rate. Based on the difference between the upper limit value, the lower limit value, and the current yaw rate change rate, it is determined whether the inter-wheel active torque distribution feedforward adjustment mode meets the second preset activation condition, thereby determining that the wheel distribution is at the on / off threshold. When the second preset activation condition is met, the wheel distribution is activated, triggering the corresponding function so that the corresponding torque distribution can be performed subsequently, and finally the target torque of at least one drive wheel is determined.

[0103] When the torque distribution mode is the inter-wheel torque distribution feedback adjustment mode, the embodiments of this application can obtain the threshold value corresponding to the inter-wheel torque distribution feedback adjustment mode through dynamic parameters such as the actual road adhesion coefficient, the actual vehicle speed, the current steering wheel angle, the current rear axle slip angle, and the vehicle emergency factor. The threshold value can include the upper limit value and the lower limit value of the yaw rate change difference. Based on the upper limit value, the lower limit value, and the current yaw rate change difference, it is determined whether the inter-wheel torque distribution feedback adjustment mode meets the third preset activation condition, and then it is determined that the wheel distribution is at the on / off threshold. When the third preset activation condition is met, the wheel distribution is activated, and the corresponding function is triggered so that the corresponding torque distribution can be performed subsequently, and finally the target torque of at least one drive wheel is determined.

[0104] For example, in understeering conditions:

[0105] The feedback torque under understeer conditions is calculated by the difference between the actual yaw rate and the target yaw rate. The yaw torque can be obtained from the yaw rate and inertia. The feedback is controlled and adjusted by a PID (proportion-integral-differential) controller to eliminate steady-state deviation and ensure rapid response. The feedback torque can also be corrected by adjusting the proportional-integral-differential of the PID controller according to the adhesion coefficient, vehicle speed, yaw difference, and driving mode, thereby correcting the feedback torque.

[0106] The feedforward torque under understeering conditions is calculated by the difference between the actual yaw rate and the target yaw rate. The yaw torque can be obtained by looking up a table using the road adhesion coefficient, vehicle speed, and the difference between the actual and target yaw angular velocities, or by looking up a table using the difference between the road adhesion coefficient, vehicle speed, and the rate of change of the actual and target yaw angular velocities.

[0107] Under oversteering conditions:

[0108] The feedback torque during oversteering is calculated by the difference between the actual yaw rate and the target yaw rate. The yaw torque can be obtained from the yaw rate and inertia. The feedback is controlled and adjusted by a PID controller to eliminate steady-state deviation and ensure rapid response. The feedback torque can also be corrected by adjusting the proportional-integral-derivative of the PID controller based on the adhesion coefficient, vehicle speed, yaw difference, and driving mode, thereby correcting the feedback torque.

[0109] Increase yaw compensation for changes in rear axle slip angle to the feedback torque;

[0110] The feedforward torque during oversteering conditions is calculated by taking the difference between the actual yaw rate and the target yaw rate. The yaw torque can be obtained by looking up a table using the road adhesion coefficient, vehicle speed, and the difference between the actual and target yaw rates, or by looking up a table using the difference between the road adhesion coefficient, vehicle speed, and the rate of change of the actual and target yaw rates.

[0111] Optionally, in one embodiment of this application, determining the target torque of at least one drive axle or at least one drive wheel includes: determining the basic distribution torque ratio of the rear drive axle in the at least one drive axle; obtaining the basic change ratio of the rear drive axle based on the vehicle's yaw rate difference; obtaining the change ratio of the rear drive axle based on the vehicle's actual speed and the actual road adhesion coefficient; obtaining the current demand distribution ratio of the rear drive axle by subtracting the change ratio of the rear drive axle from the basic distribution ratio; multiplying the vehicle's total torque by the demand distribution ratio of the rear drive axle to obtain the target torque of the rear drive axle; obtaining the original target torque of the drive wheel based on the current torque difference between the left and right drive wheels in the at least one drive wheel; obtaining the actual torque difference of the drive wheels based on the vehicle's target yaw moment, and obtaining the target torques of the left and right drive wheels based on the actual torque difference and the original target torque; wherein, the emergency factor is obtained from at least one of the vehicle's yaw moment, actual vehicle speed and driving mode, and the road adhesion coefficient of the current road.

[0112] like Figure 2 As shown, in this embodiment of the application, the wheelbase drive torque distribution or wheel end drive torque distribution can be performed after the torque distribution function is activated, the yaw moment is calculated and combined with the factor.

[0113] The emergency factor can be assessed based on changes in vehicle yaw, speed, and road surface adhesion, and the torque distribution can be adjusted accordingly. For example, the emergency factor can be obtained by looking up a table using the difference between the target yaw force and the actual yaw force, the understeer angle, and the oversteer angle. The emergency factor can then be adjusted by accumulating these factors and considering factors such as vehicle speed, road surface adhesion, and driving mode.

[0114] Regarding inter-shaft drive torque distribution, one possible approach is... Figure 3As shown, in this embodiment of the application, the actual transfer torque ratio determined by the rear drive shaft allocation ratio and the attenuation transfer ratio can be used to derive the required torque after attenuation transfer of each shaft based on the shaft torque judgment, and the required wheel end torque after shaft allocation can be derived from the current wheel end torque after shaft allocation, thereby realizing the inter-shaft drive torque distribution.

[0115] Specifically, it may include the following steps:

[0116] S1: Rear drive shaft distribution ratio. Based on the rear drive shaft distribution ratio, the actual transfer torque ratio determined by the attenuation transfer ratio, and the required torque after attenuation transfer of each shaft, the current wheel end torque after shaft distribution is used to derive the required wheel end torque after shaft distribution.

[0117] In this embodiment, the torque distribution ratio of the rear drive shaft can be determined based on the difference between the target yaw and the actual yaw. The difference between the target and the actual yaw minus the minimum calibrated change of the difference is defined as 'a', and the difference between the maximum calibrated amount of the difference and the minimum calibrated amount of the difference is defined as 'b'. The ratio of 'a' to 'b' can be tentatively set as the basic change of the rear drive shaft torque. Then, the correction amount of the rear drive shaft torque change is obtained by looking up a table based on vehicle speed and road adhesion, thereby obtaining the change amount of the rear drive shaft torque c.

[0118] When the current steering condition is understeer, the rear drive shaft needs to be given additional torque. The required distribution ratio of the rear drive shaft can be obtained by adding the basic distribution ratio of the rear drive shaft to the torque change ratio of the rear drive shaft.

[0119] When the current steering condition is oversteering, the rear drive shaft needs to reduce torque. The required distribution ratio of the rear drive shaft can be obtained by subtracting the shaft torque change ratio from the basic distribution ratio of the rear drive shaft.

[0120] It is important to note that changes in the rear drive shaft demand ratio must ensure that the inter-shaft torque distribution function is active. The transition from the basic rear drive shaft distribution ratio to the rear drive shaft demand distribution ratio must be smooth and the output must be controlled by upper and lower limits.

[0121] S2: Attenuated torque transfer ratio. In the process of actively reducing or increasing yaw torque in this embodiment, during the torque redistribution at the axle or wheel end, the distributed torque may exceed the limit torque. The excess torque is attenuated before being transferred to another drive axle or drive wheel. When the difference between the target yaw and the actual yaw reaches a certain value, and the vehicle has a certain speed without anti-rudder triggering, anti-rudder is defined as the target yaw multiplied by the actual yaw multiplied by a factor less than zero, activating the calculation of the attenuated transfer ratio. The ratio of the target yaw angular velocity minus a certain correction amount to the actual yaw angular velocity is used. This ratio is then filtered by a first-order low-pass filter and compared with the road surface adhesion table to obtain the attenuated transfer ratios for the front and rear drive axles and a single drive wheel, respectively.

[0122] S3: Axle torque determination. The required torque of the rear drive axle is obtained by multiplying the required torque of the whole vehicle by the required torque distribution ratio of the rear drive axle. The required torque of the rear drive axle minus the required torque of the rear drive axle is the torque output of the rear drive axle. The required torque of the front drive axle is obtained by subtracting the required torque of the rear drive axle from the required torque of the whole vehicle. The required torque of the front drive axle minus the required torque of the front drive axle is obtained by subtracting the required torque of the front drive axle from the required torque of the front drive axle.

[0123] When understeering occurs, the rear drive axle increases torque. When this increase exceeds its limit, the rear drive axle's output torque multiplied by the attenuated transfer ratio equals the increase in torque required by the front drive axle. The sum of this increase and the required front drive axle torque, after being limited by the maximum torque capacity, equals the final required front drive axle torque. Similarly, the final required rear drive axle torque, after being limited by the maximum capacity, equals the final required rear drive axle torque.

[0124] During oversteer, the front drive shaft increases torque. When this increase exceeds its capacity limit, the output torque of the front drive shaft multiplied by the attenuated transfer ratio is the increase in torque for the rear drive shaft. The increase in torque for the rear drive shaft plus the required torque for the rear drive shaft, after being limited by its maximum torque capacity, equals the final required torque for the rear drive shaft. The required torque for the front drive shaft, after being limited by its maximum capacity, equals the final required torque for the front drive shaft.

[0125] S4: Current wheel-end torque after axle distribution. The principle of wheel distribution is that the torque of the outer drive wheel increases more in understeer conditions and the torque of the inner drive wheel increases more in oversteer conditions. The wheel with more torque may turn out torque according to its maximum torque capacity. The turned-out part will be attenuated and then transferred to another wheel.

[0126] The allocation method is as follows:

[0127] The original target torque of the outer drive wheel is calculated by adding the required torque to the torque difference between the left and right drive wheels of the current drive shaft and dividing by 2. The original target torque of the outer drive wheel minus the torque difference between the left and right drive wheels of the current drive shaft is the original target torque of the inner drive wheel of the current drive shaft. All original target torques must be limited by the maximum torque capacity before being output as original target torque 1. The difference between the original target torque and original target torque 1 is the wheel-end rotation torque. The outer drive wheel rotation torque multiplied by the single-wheel attenuation transfer ratio is the actual rotation torque from the outer drive wheel to the inner drive wheel. The original target torque 1 of the inner drive wheel plus the actual rotation torque is the original target torque 2 of the inner drive wheel. The original target torque 2 of the inner drive wheel, after being limited by the maximum torque capacity, is output as the original target torque 3 of the inner drive wheel.

[0128] The actual torque output from the inner drive wheel to the outer drive wheel is calculated by multiplying the torque output by the single-wheel attenuation transfer ratio. The original target torque 1 of the outer drive wheel plus the actual torque output equals the original target torque 2 of the outer drive wheel. The original target torque 2 of the outer drive wheel, after being limited by the maximum torque capacity, becomes the original target torque 3 of the outer drive wheel. When the inter-axle active torque distribution module is activated, the current wheel-end torque must undergo a smooth transition to the original target torque 3.

[0129] Regarding the redistribution of wheel-end drive torque, embodiments of this application can determine the torque distribution difference between the left and right sides by converting the target yaw torque into a drive torque distribution difference. Then, based on the torque difference between the left and right drive wheels, the torque of the outer wheel after axle distribution, and the attenuation transfer ratio, the required wheel-end torque is obtained. After further filtering and compensation through arbitration judgment, a smooth transition is achieved, resulting in the required wheel-end drive torque, i.e., the target torque of at least one drive wheel.

[0130] For example, such as Figure 4 As shown, wheel-end drive torque distribution may include the following steps:

[0131] S1: Yaw torque converted into drive torque distribution difference. In this embodiment, the target yaw moment is divided by the wheelbase multiplied by the sum of the rolling radii of the front and rear wheels to obtain the original value of the drive torque difference between the left and right sides. This difference is then corrected by looking up tables based on the road adhesion coefficient, vehicle speed, and emergency factor, resulting in a pre-processed drive torque distribution difference. A compensation value for the drive torque distribution difference between the left and right sides is then obtained by looking up the total drive torque. This compensation value is added to the pre-processed drive torque distribution difference, and then, after being constrained by the maximum and minimum drive torque distribution difference, a first-order low-pass filter is applied to output the drive torque distribution difference between the left and right sides. Alternatively, the slope of the change in the drive torque distribution difference between the left and right sides can be defined by calibrating the time and using a first-order low-pass filter.

[0132] S2: Wheel-end drive torque distribution calculation. Combined with... Figures 5-7 As shown, where, Figure 5 This is a schematic diagram illustrating the distribution process between the inner and outer drive wheels of the rear drive shaft under understeer conditions. Figure 6 A schematic diagram illustrating the process of obtaining the actual change difference in torque at the front drive axle wheel end; Figure 7 A schematic diagram illustrating the distribution process of the inner and outer drive wheels on the front drive shaft.

[0133] Specifically, in understeer conditions, the outer drive wheel increases torque, while the inner drive wheel decreases torque. Since the rear drive axle's drive torque is greater than the front drive axle's, and following the rear drive axle's priority distribution principle, the difference in drive torque distribution between the left and right sides of the rear drive axle can be tentatively defined as the difference in drive torque distribution between the left and right sides of the rear drive axle. Dividing the difference in drive torque distribution between the left and right sides of the rear drive axle by 2 gives the change in torque distribution per wheel on the rear drive axle. The torque of the outer wheel after distribution, plus the change in torque distribution per wheel, gives the original demand for torque distribution at the outer wheel end of the rear drive axle. Subtracting the torque limitation of the outer wheel end from the original torque distribution gives the initial rotation amount of the outer wheel end of the rear drive axle. Multiplying this rotation amount by the transfer ratio after single-wheel attenuation gives the actual rotation amount from the outer drive wheel to the inner drive wheel of the rear drive axle. The torque of the inner wheel after the rear drive axle distribution minus the change is the original demand for the inner wheel end of the rear drive axle. This original demand, after being limited by the maximum torque, is added to the actual rotation distance from the outer drive wheel to the inner drive wheel, and then further limited by the maximum torque to output the required torque for the inner wheel end of the rear drive axle. Similarly, the original torque distributed to the outer wheel end of the rear drive axle, plus the rotation distance limited by the inner torque, is added to the original torque, and then further limited by the maximum torque to output the required torque for the outer wheel end of the rear drive axle.

[0134] The difference between the required torque of the outer drive wheel and the required torque of the inner drive wheel on the rear drive axle represents the actual change in torque demand between the inner and outer drive wheels of the rear drive axle. The difference between the torque of the outer wheel after distribution to the rear drive axle and the torque of the inner wheel after distribution to the rear drive axle represents the current change in torque demand between the inner and outer drive wheels of the rear drive axle. Subtracting the difference between the two torques from the rear drive axle represents the actual change in torque demand of the rear drive axle under yaw moment. The difference between the torque distribution difference on the left and right sides and the difference in actual torque change of the rear drive axle represents the actual change in torque demand of the front drive axle.

[0135] Under understeer conditions, the front drive axle distributes torque to the inner and outer drive wheels. The difference between the actual torque change of the front drive axle and 2 gives the torque change per wheel. The torque of the outer wheel after distribution, plus the torque change per wheel, gives the original torque requirement for the outer wheel. The original torque requirement for the outer wheel minus the torque limit gives the initial wheel rotation distance. Multiplying this rotation distance by the single-wheel attenuation transfer ratio gives the actual wheel rotation distance from the outer drive wheel to the inner drive wheel. The torque of the inner wheel after distribution, minus the torque change, gives the original torque requirement for the inner wheel. This original torque requirement, after being limited by the maximum torque, is added to the actual wheel rotation distance from the outer drive wheel to the inner drive wheel, and then further limited by the maximum torque to give the torque requirement for the inner wheel. The original torque requirement for the outer wheel, plus the torque rotation distance limited by the inner wheel, and then further limited by the maximum torque, gives the torque requirement for the outer wheel.

[0136] In oversteering conditions, the outer drive wheels reduce torque, while the inner drive wheels increase torque. The difference in torque distribution between the left and right sides of the rear drive axle, divided by 2, represents the change in torque distribution per wheel on the rear drive axle. The torque of the inner wheel after distribution, plus the change in torque distribution per wheel, represents the original torque requirement for the inner wheel end of the rear drive axle. Subtracting the torque limit from the original torque distribution on the inner wheel end of the rear drive axle gives the initial rotation distance of the inner wheel end. Multiplying this rotation distance by the transfer ratio after single-wheel attenuation gives the actual rotation distance from the inner drive wheel to the outer drive wheel. Subtracting the change in torque distribution from the outer wheel after distribution on the rear drive axle gives the original torque requirement for the outer wheel end of the rear drive axle. This original torque requirement, after being limited by the maximum torque, is added to the actual rotation distance from the inner drive wheel to the outer drive wheel, and then further limited by the maximum torque, outputting the required torque for the outer wheel end of the rear drive axle. Finally, the original torque distribution on the inner wheel end of the rear drive axle, plus the rotation distance limited by the torque limit on the outer wheel end, and then further limited by the maximum torque, outputting the required torque for the inner wheel end of the rear drive axle.

[0137] During oversteer, the torque distribution between the inner and outer drive wheels of the front drive shaft is as follows: The difference in torque distribution between the left and right sides of the front drive shaft divided by 2 gives the change in torque distribution per wheel. The torque of the inner wheel after distribution, plus the change in torque distribution per wheel, represents the initial demand for torque distribution to the inner wheel end. The initial torque distribution to the inner wheel end minus the torque limit of the inner wheel end gives the initial wheel rotation distance of the inner wheel end. Multiplying this rotation distance by the transfer ratio after single-wheel attenuation gives the actual wheel rotation distance from the inner drive wheel to the outer drive wheel. The torque distribution to the outer wheel after distribution, minus the change in torque distribution, represents the initial demand for torque distribution to the outer wheel end. This initial demand, after being limited by the maximum torque, is added to the actual wheel rotation distance from the inner drive wheel to the outer drive wheel, and then further limited by the maximum torque to output the required torque for the outer wheel end of the front drive shaft. Finally, the initial torque distribution to the inner wheel end, plus the wheel rotation distance limited by the torque limit of the outer wheel end, and then further limited by the maximum torque, outputs the required torque for the inner wheel end of the front drive shaft.

[0138] S3: Arbitration Judgment. In some embodiments, the wheel-end torque demand when the vehicle turns left needs to transition smoothly to the wheel-end torque demand when turning right. The smooth transition time can be obtained by looking up a table from the slope of the change in torque difference between the current left and right drive wheels. When the speed of change of steering wheel angle is greater than a certain value, and the difference between the target and actual yaw angle is greater than a certain value, the wheel-end torque demand is compensated, and the torque change is smooth. The smooth transition from the wheel-end torque after inter-axle distribution to the wheel-end torque after wheel-end drive redistribution is triggered by the activation of inter-wheel active torque distribution.

[0139] Optionally, in one embodiment of this application, the method further includes: determining whether the target torque of at least one drive shaft is greater than the corresponding first maximum limit torque; if it is greater than the corresponding first maximum limit torque, controlling the output of the corresponding drive shaft with the first maximum limit torque, obtaining a first excess torque based on the target torque and the first maximum limit torque, attenuating the first excess torque with a first preset attenuation ratio to obtain a first attenuated torque, and transferring the first attenuated torque to another drive shaft other than the corresponding drive shaft for output.

[0140] It is understandable that during the process of actively reducing or increasing yaw torque, the distributed torque may exceed the limit torque during the torque redistribution process at the axle or wheel end. That is to say, the current maximum torque of the drive axle is limited based on the maximum torque. The torque exceeding the limit can be attenuated and then transferred to another drive axle. For the same road surface, the maximum limit torque is a constant value.

[0141] In some embodiments, when the difference between the target yaw rate and the actual yaw rate reaches a certain value, and the vehicle has a certain speed without anti-rudder triggering, anti-rudder is defined as the target yaw rate multiplied by the actual yaw rate by a factor less than zero, activating the calculation of the attenuation transfer ratio. The ratio of the target yaw rate minus a certain correction amount to the actual yaw rate is obtained. This ratio is then filtered by a first-order low-pass filter and compared with the road surface adhesion table to obtain the attenuation transfer ratio of the front and rear drive shafts, i.e., the first preset attenuation ratio. The first excess torque is attenuated by the first preset attenuation ratio, and according to the attenuation result, the corresponding torque is transferred to the output torque of another drive shaft other than the corresponding drive shaft.

[0142] When the target torque of the drive shaft is less than the first maximum limiting torque, the embodiment of this application does not need to perform the corresponding attenuation transfer calculation. It can be seen that attenuation transfer can not be triggered under all operating conditions and needs to be analyzed according to the actual steering conditions of the vehicle.

[0143] Optionally, in one embodiment of this application, the method further includes: determining whether the target torque of at least one drive wheel is greater than the corresponding second maximum limit torque; if it is greater than the corresponding second maximum limit torque, controlling the output of the corresponding drive wheel with the second maximum limit torque, obtaining a second excess torque based on the target torque and the second maximum limit torque, attenuating the second excess torque with a second preset attenuation ratio to obtain a second attenuated torque, and transferring the second attenuated torque to the output torque of another drive wheel coaxial with the corresponding drive wheel.

[0144] In other embodiments, after the calculation of the transfer ratio after activation attenuation, the present application embodiment can use the target yaw rate minus a certain correction amount to obtain the ratio of the value to the actual yaw rate. After the ratio is filtered by a first-order low-pass filter and looked up with the road surface adhesion table, the attenuation transfer ratio of the front and rear drive shafts can be obtained respectively, that is, the second preset attenuation ratio is obtained. The second excess torque is attenuated by the second preset attenuation ratio, and according to the attenuation result, the corresponding torque is transferred to the output torque of another drive wheel other than the corresponding drive wheel.

[0145] When the target torque of the drive shaft is less than the second maximum limit torque, the embodiment of this application does not need to perform the corresponding attenuation transfer calculation. It can be seen that attenuation transfer can not be triggered under all operating conditions and needs to be analyzed according to the actual steering conditions of the vehicle.

[0146] In summary, this application can obtain the vehicle's actual yaw rate when the vehicle is in four-wheel drive mode with distributed drive, and when the current steering condition is understeer or oversteer. Based on the actual yaw rate, the speed difference between the actual yaw rate and the target yaw rate, or the rate of change of speed, the torque distribution mode of the vehicle is determined. This allows for the calculation of the target torque for at least one drive axle or at least one drive wheel under both understeer and oversteer conditions. The application can distribute torque according to changes in the vehicle's yaw rate to calculate the target torque under different conditions, thereby actively reducing or increasing yaw torque to improve understeer or oversteer, enhance vehicle steering stability, and effectively ensure vehicle safety. This solves the problems of related technologies that, when redistributing torque under understeer or oversteer conditions, cannot reasonably distribute excessive torque and cannot adjust in real time according to vehicle conditions, making it difficult to effectively address understeer or oversteer conditions, thus affecting vehicle steering stability and potentially leading to serious traffic accidents.

[0147] Figure 8 This is a schematic diagram of the structure of a distributed torque distribution device for a vehicle provided in an embodiment of this application.

[0148] For example, such as Figure 8 As shown, the device 10 may include: an identification module 100, a calculation module 200, and an allocation module 300.

[0149] Specifically, the identification module 100 is used to identify the current steering condition of the vehicle when the vehicle is in four-wheel drive mode distributed drive.

[0150] The calculation module 200 is used to obtain the actual yaw rate of the vehicle when the current steering condition is understeering or oversteering, and to determine the torque distribution mode of the vehicle based on the speed value of the actual yaw rate, the speed difference between the actual yaw rate and the target yaw rate, or the speed change rate.

[0151] The distribution module 300 is used to calculate the target torque of at least one drive axle or at least one drive wheel of the vehicle under understeer or oversteer conditions, based on the torque distribution mode.

[0152] Optionally, in one embodiment of this application, the vehicle's distributed torque distribution device 10 further includes a first judgment module and a first output module.

[0153] The first judgment module is used to determine whether the target torque of at least one drive shaft is greater than the corresponding first maximum limit torque.

[0154] The first output module is used to control the output of the corresponding drive shaft when the torque exceeds the corresponding first maximum limit torque, and to obtain the first excess torque according to the target torque and the first maximum limit torque, and to attenuate the first excess torque by a first preset attenuation ratio to obtain the first attenuated torque, and to transfer the first attenuated torque to another drive shaft other than the corresponding drive shaft for output.

[0155] Optionally, in one embodiment of this application, the vehicle's distributed torque distribution device 10 further includes: a second judgment module and a second output module.

[0156] The second judgment module is used to determine whether the target torque of at least one drive wheel is greater than the corresponding second maximum limit torque.

[0157] The second output module is used to control the output of the corresponding drive wheel when the torque exceeds the corresponding second maximum limit torque, and to obtain the second excess torque based on the target torque and the second maximum limit torque, and to attenuate the second excess torque by a second preset attenuation ratio to obtain the second attenuated torque, and to transfer the second attenuated torque to the output torque of another drive wheel coaxial with the corresponding drive wheel.

[0158] Optionally, in one embodiment of this application, the calculation module 200 includes: an acquisition unit, a first calculation unit, a second calculation unit, and a third calculation unit.

[0159] The acquisition unit is used to acquire the yaw moment of the vehicle.

[0160] The first calculation unit is used to set the torque distribution mode to the inter-axis active torque distribution mode when the yaw moment is greater than the first preset threshold.

[0161] The second calculation unit is used to set the torque distribution mode to the inter-wheel active torque distribution feedforward adjustment mode when the absolute value of the difference between the actual rate of change of yaw rate and the target rate of change of yaw rate is greater than the second preset threshold.

[0162] The third calculation unit is used to set the torque distribution mode to wheel torque distribution feedback adjustment mode when the absolute value of the difference between the target yaw rate and the actual yaw rate is greater than a third preset threshold.

[0163] Optionally, in one embodiment of this application, the allocation module 300 includes: a first judgment unit, a second judgment unit, and a third judgment unit.

[0164] The first judgment unit is used to determine the first threshold value of the yaw moment based on the actual adhesion coefficient of the road, the current rear axle slip angle of the vehicle and the current driving mode when the torque distribution mode is the inter-axle active torque distribution mode, and to use the first threshold value to determine whether the inter-axle active torque distribution mode meets the first preset activation condition, so as to determine the target torque of at least one drive axle when the inter-axle active torque distribution mode meets the first preset activation condition.

[0165] The second judgment unit is used to determine the second threshold value of the difference in yaw rate change rate based on the actual road adhesion coefficient, the actual vehicle speed, the current steering wheel angle, the current rear axle slip angle, and the vehicle emergency factor when the torque distribution mode is the inter-wheel active torque distribution feedforward adjustment mode. It then uses the second threshold value to determine whether the inter-wheel active torque distribution feedforward adjustment mode meets the second preset activation condition. When the inter-wheel active torque distribution feedforward adjustment mode meets the second preset activation condition, it determines the target torque of at least one drive wheel.

[0166] The third judgment unit is used to determine the third threshold value of the yaw rate change difference based on the actual road adhesion coefficient, the actual vehicle speed, the current steering wheel angle, the current rear axle slip angle, and the vehicle emergency factor when the torque distribution mode is the inter-wheel torque distribution feedback adjustment mode. It then uses the third threshold value to determine whether the inter-wheel torque distribution feedback adjustment mode meets the third preset activation condition. When the inter-wheel torque distribution feedback adjustment mode meets the third preset activation condition, it determines the target torque of at least one drive wheel.

[0167] Optionally, in one embodiment of this application, the allocation module 300 is configured to: determine the basic allocation torque ratio of the rear drive axle in at least one drive axle; obtain the basic change ratio of the rear drive axle based on the yaw rate difference of the vehicle; obtain the change ratio of the rear drive axle based on the actual vehicle speed and the actual road adhesion coefficient; obtain the current demand allocation ratio of the rear drive axle by subtracting the change ratio of the rear drive axle from the basic allocation ratio; obtain the target torque of the rear drive axle by multiplying the total vehicle torque by the demand allocation ratio of the rear drive axle; obtain the original target torque of the drive wheels based on the current torque difference between the left and right drive wheels in at least one drive wheel; obtain the actual torque difference of the drive wheels based on the target yaw moment of the vehicle, and obtain the target torques of the left and right drive wheels based on the actual torque difference and the original target torque.

[0168] Optionally, in one embodiment of this application, the factor is obtained from at least one of the vehicle's yaw moment, actual vehicle speed and driving mode, and the road surface adhesion coefficient of the current road.

[0169] In summary, this application can obtain the vehicle's actual yaw rate when the vehicle is in four-wheel drive mode with distributed drive, and when the current steering condition is understeer or oversteer. Based on the actual yaw rate, the speed difference between the actual yaw rate and the target yaw rate, or the rate of change of speed, the torque distribution mode of the vehicle is determined. This allows for the calculation of the target torque for at least one drive axle or at least one drive wheel under both understeer and oversteer conditions. The application can distribute torque according to changes in the vehicle's yaw rate to calculate the target torque under different conditions, thereby actively reducing or increasing yaw torque to improve understeer or oversteer, enhance vehicle steering stability, and effectively ensure vehicle safety. This solves the problems of related technologies that, when redistributing torque under understeer or oversteer conditions, cannot reasonably distribute excessive torque and cannot adjust in real time according to vehicle conditions, making it difficult to effectively address understeer or oversteer conditions, thus affecting vehicle steering stability and potentially leading to serious traffic accidents.

[0170] Figure 9 This is a schematic diagram of the structure of a vehicle according to an embodiment of this application. The vehicle may include:

[0171] The memory 901, the processor 902, and the computer program stored on the memory 901 and capable of running on the processor 902.

[0172] When processor 902 executes the program, it implements the distributed torque distribution method for vehicles provided in the above embodiments.

[0173] Furthermore, the vehicle also includes:

[0174] Communication interface 903 is used for communication between memory 901 and processor 902.

[0175] The memory 901 is used to store computer programs that can run on the processor 902.

[0176] The memory 901 may include high-speed RAM (Random Access Memory) memory, and may also include non-volatile memory, such as at least one disk storage.

[0177] If the memory 901, processor 902, and communication interface 903 are implemented independently, then the communication interface 903, memory 901, and processor 902 can be interconnected via a bus to complete communication between them. The bus can be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus, or an EISA (Extended Industry Standard Architecture) bus, etc. The bus can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 9 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0178] Optionally, in a specific implementation, if the memory 901, processor 902, and communication interface 903 are integrated on a single chip, then the memory 901, processor 902, and communication interface 903 can communicate with each other through an internal interface.

[0179] The processor 902 may be a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of this application.

[0180] This embodiment also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described distributed torque distribution method for vehicles.

[0181] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0182] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0183] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A method for distributed torque distribution in a vehicle, characterized in that, Includes the following steps: When the vehicle is in four-wheel drive mode with distributed drive, the current steering condition of the vehicle is identified. When the current steering condition is understeering or oversteering, the actual yaw rate of the vehicle is obtained, and the yaw moment of the vehicle is obtained. When the yaw moment is greater than a first preset threshold, the torque distribution mode is the inter-axis active torque distribution mode; If the absolute value of the difference between the actual rate of change of yaw rate and the target rate of change of yaw rate is greater than the second preset threshold, the torque distribution mode is the inter-wheel active torque distribution feedforward adjustment mode. If the absolute value of the difference between the target yaw rate and the actual yaw rate is greater than a third preset threshold, the torque distribution mode is the inter-wheel torque distribution feedback adjustment mode. Based on the torque distribution mode, the target torque of at least one drive axle or at least one drive wheel of the vehicle is calculated under the understeer condition or the oversteer condition, respectively. If the torque distribution mode is the inter-axle active torque distribution mode, then a first threshold value of the yaw moment is determined based on the actual road adhesion coefficient, the current rear axle slip angle of the vehicle and the current driving mode, and the first threshold value is used to determine whether the inter-axle active torque distribution mode meets the first preset activation condition, so as to determine the target torque of the at least one drive axle when the inter-axle active torque distribution mode meets the first preset activation condition. If the torque distribution mode is the inter-wheel active torque distribution feedforward adjustment mode, then a second threshold value of the difference in yaw rate change rate is determined based on the actual road adhesion coefficient, the actual vehicle speed, the current steering wheel angle, the current rear axle slip angle, and the vehicle emergency factor. The second threshold value is then used to determine whether the inter-wheel active torque distribution feedforward adjustment mode meets the second preset activation condition. When the inter-wheel active torque distribution feedforward adjustment mode meets the second preset activation condition, the target torque of the at least one drive wheel is determined. If the torque distribution mode is the inter-wheel torque distribution feedback adjustment mode, then a third threshold value for the difference in yaw rate change is determined based on the actual road adhesion coefficient, the actual vehicle speed, the current steering wheel angle, the current rear axle slip angle, and the vehicle emergency factor. The third threshold value is then used to determine whether the inter-wheel torque distribution feedback adjustment mode meets the third preset activation condition. When the inter-wheel torque distribution feedback adjustment mode meets the third preset activation condition, the target torque of the at least one drive wheel is determined.

2. The method according to claim 1, characterized in that, Also includes: Determine whether the target torque of the at least one drive shaft is greater than the corresponding first maximum limit torque; If the torque exceeds the corresponding first maximum limit torque, the corresponding drive shaft output is controlled by the first maximum limit torque. A first excess torque is obtained based on the target torque and the first maximum limit torque. The first excess torque is then attenuated by a first preset attenuation ratio to obtain a first attenuated torque. The first attenuated torque is then transferred to another drive shaft other than the corresponding drive shaft for output.

3. The method according to claim 1, characterized in that, Also includes: Determine whether the target torque of the at least one drive wheel is greater than the corresponding second maximum limit torque; If the torque exceeds the corresponding second maximum limit torque, the output of the corresponding drive wheel is controlled by the second maximum limit torque. A second excess torque is obtained based on the target torque and the second maximum limit torque. The second excess torque is then attenuated by a second preset attenuation ratio to obtain a second attenuated torque. The second attenuated torque is then transferred to the output torque of another drive wheel coaxial with the corresponding drive wheel.

4. The method according to claim 1, characterized in that, Determining the target torque of the at least one drive shaft or at least one drive wheel includes: Determine the basic torque distribution ratio of the rear drive shaft in the at least one drive shaft; The basic change ratio of the rear drive shaft is obtained based on the yaw rate difference of the vehicle. The rear drive shaft variation ratio is obtained based on the actual vehicle speed and the actual road adhesion coefficient. The current demand allocation ratio of the rear drive shaft is obtained by subtracting the rear drive shaft change ratio from the basic distribution torque ratio. The target torque of the rear drive shaft is obtained by multiplying the total torque of the vehicle by the demand distribution ratio of the rear drive shaft. The original target torque of the drive wheel is obtained based on the current torque difference between the left drive wheel and the right drive wheel in at least one drive wheel; The actual torque difference of the drive wheels is obtained based on the target yaw moment of the vehicle, and the target torques of the left and right drive wheels are obtained based on the actual torque difference and the original target torque.

5. The method according to claim 4, characterized in that, The emergency factor is obtained from at least one of the vehicle's yaw moment, actual vehicle speed and driving mode, and the road surface adhesion coefficient of the current road.

6. A distributed torque distribution device for a vehicle, characterized in that, The distributed torque distribution device is used to perform the method of any one of claims 1-5, and the distributed torque distribution device comprises: The identification module is used to identify the vehicle's current steering condition when the vehicle is in four-wheel drive mode with distributed drive. The calculation module is used to obtain the actual yaw rate of the vehicle when the current steering condition is understeering or oversteering, and to determine the torque distribution mode of the vehicle based on the absolute value of the difference between the rate of change of the actual yaw rate and the rate of change of the target yaw rate, and the absolute value of the difference between the target yaw rate and the actual yaw rate. The distribution module is used to calculate, based on the torque distribution mode, the target torque of at least one drive shaft or at least one drive wheel of the vehicle under the understeer condition or the oversteer condition.

7. A vehicle, characterized in that, include: A memory, a processor, and a computer program stored in the memory and executable on the processor, the processor executing the program to implement the distributed torque distribution method for a vehicle as described in any one of claims 1-5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the distributed torque distribution method for the vehicle as described in any one of claims 1-5.

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