CN117021975A

CN117021975A - Distributed torque distribution method and device for vehicle, vehicle and storage medium

Info

Publication number: CN117021975A
Application number: CN202311123499.0A
Authority: CN
Inventors: 梁飞飞; 刘国瑞; 张荡
Original assignee: Zhejiang Geely Holding Group Co Ltd; Weirui Electric Automobile Technology Ningbo Co Ltd; Zhejiang Zeekr Intelligent Technology Co Ltd
Current assignee: Zhejiang Geely Holding Group Co Ltd; Weirui Electric Automobile Technology Ningbo Co Ltd; Zhejiang Zeekr Intelligent Technology Co Ltd
Priority date: 2023-08-31
Filing date: 2023-08-31
Publication date: 2023-11-10

Abstract

The application provides a distributed torque distribution method and device of a vehicle, the vehicle and a storage medium, wherein the method comprises the following steps: during the distributed driving process of the vehicle in the four-wheel drive mode, the current steering working condition of the vehicle is identified; under the condition that the current steering working condition is an understeer working condition or an oversteer working condition, acquiring the actual yaw rate of the vehicle, and determining a torque distribution mode of the vehicle according to a speed value of the actual yaw rate, a speed difference value between the actual yaw rate and the target yaw rate or a speed change rate; based on the torque distribution pattern, a target torque of at least one drive axle or at least one drive wheel of the vehicle in an understeer condition or an oversteer condition, respectively, is calculated. According to the method, torque distribution can be carried out according to the change of the yaw rate of the vehicle so as to respectively calculate driving torques under different working conditions, so that the yaw torque is actively reduced or the yaw torque is actively lifted, the understeer or oversteer condition is improved, and the steering stability of the vehicle is improved.

Description

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

Technical Field

The present application relates to the field of vehicle power driving, and more particularly, to a distributed torque distribution method and apparatus for a vehicle, and a storage medium.

Background

At present, four-wheel independent distribution driving vehicles in the industry are in a concept vehicle stage or an immature stage, and torque distribution of front wheels, rear wheels, left wheels and right wheels in a curve is also in a matching fumbling stage.

In the related technology, when a vehicle has obvious understeer working condition or oversteer working condition, the sideslip degree of a push head or a rear driving shaft can be judged through the change of the yaw rate, the driving torque distribution proportion of a target front driving shaft and a rear driving shaft is determined, the yaw torque is modified through modifying the front driving torque distribution proportion and the rear driving torque distribution proportion, the yaw rate of the vehicle is further modified, the risk of push head or tail flicking of the vehicle is reduced, and the vehicle control stability is improved.

However, when torque is redistributed under understeer working conditions or oversteer working conditions, the torque overrun cannot be reasonably distributed, and cannot be accurately adjusted according to the vehicle conditions, so that the understeer or oversteer working conditions of the vehicle are difficult to effectively cope with, the steering stability of the vehicle is affected, serious traffic accidents are even easily caused, and the problem is to be solved.

Disclosure of Invention

The application provides a distributed torque distribution method, a distributed torque distribution device, a distributed torque distribution vehicle and a distributed torque distribution storage medium of a vehicle.

In a first aspect, a distributed torque distribution method for a vehicle is provided, the method comprising:

during the distributed driving process of the vehicle in the four-wheel drive mode, the current steering working condition of the vehicle is identified;

under the condition that the current steering working condition is an understeer working condition or an oversteer working condition, acquiring the actual yaw rate of the vehicle, and determining a torque distribution mode of the vehicle according to a speed value of the actual yaw rate, a speed difference value between the actual yaw rate and a target yaw rate or a speed change rate;

based on the torque distribution pattern, a target torque of at least one drive shaft or at least one drive wheel of the vehicle in the understeer condition or the oversteer condition, respectively, is calculated.

Through the technical scheme, the torque distribution mode can be determined according to the change of the yaw rate of the vehicle so as to respectively calculate the target torques under different working conditions, thereby actively reducing the yaw torque or improving the yaw torque, improving the understeer working condition or oversteer working condition and improving the steering stability of the vehicle.

With reference to the first aspect, in some possible implementations, the method further includes:

judging whether the target torque of the at least one driving shaft is larger than the corresponding first maximum limiting torque;

and if the torque is larger than the corresponding first maximum limiting torque, controlling the corresponding driving shaft to output according to the first maximum limiting torque, obtaining a first exceeding torque according to the target torque and the first maximum limiting torque, attenuating the first exceeding torque according to a first preset attenuation proportion, obtaining a first attenuation torque, and transferring the first attenuation torque to another driving shaft outside the corresponding driving shaft for output.

Through the technical scheme, when the target torque of the driving shaft is larger than the first maximum limiting torque, the torque exceeding the target torque is attenuated according to a certain proportion and then transferred, the steering characteristic can be ensured to be changed, and the problem that the torque is reduced rapidly due to complete attenuation is avoided.

judging whether the target torque of the at least one driving wheel is larger than a corresponding second maximum limiting torque;

and if the torque is larger than the corresponding second maximum limiting torque, controlling the output of the corresponding driving wheel by using the second maximum limiting torque, obtaining a second exceeding torque according to the target torque and the second maximum limiting torque, attenuating the second exceeding torque by using a second preset attenuation proportion, obtaining a second attenuation torque, and transferring the second attenuation torque to the output torque of another driving wheel coaxial with the corresponding driving wheel.

Through the technical scheme, when the target torque of the driving wheel is larger than the second maximum limiting torque, the torque exceeding the target torque is attenuated according to a certain proportion and then transferred, the steering characteristic can be ensured to be changed, and the problem that the torque is reduced rapidly due to complete attenuation is avoided.

With reference to the first aspect, in some possible implementations, the determining the torque distribution mode of the vehicle according to 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 includes:

Acquiring a yaw moment of the vehicle;

under the condition that the yaw moment is larger than a first preset threshold value, the torque distribution mode is an inter-axle active torque distribution mode;

the torque distribution mode is an inter-wheel active torque distribution feedforward adjustment mode in the case where an absolute value of a difference between the change rate of the actual yaw rate and the change rate of the target yaw rate is greater than a second preset threshold;

the torque distribution mode is an inter-wheel torque distribution feedback adjustment mode in the case where the absolute value of the difference between the target yaw rate and the actual yaw rate is greater than a third preset threshold.

Through the technical scheme, the torque distribution mode can be determined according to the yaw moment, the target yaw rate, the difference between the change rate of the actual yaw rate and the change rate of the target yaw rate and the difference between the target yaw rate and the actual yaw rate, so that feedforward and feedback torque distribution can be performed according to the change of the yaw rate, and the distribution torque can be attached to various steering working conditions of the vehicle.

With reference to the first aspect, in some possible implementations, the calculating, based on the torque distribution mode, a target torque of at least one drive shaft or at least one drive wheel of the vehicle in the understeer condition or the oversteer condition, respectively, includes:

If the torque distribution mode is the inter-axle active distribution torque mode, determining a first threshold value of a yaw moment according to an actual attachment coefficient of a road, a current rear axle side deflection angle of the vehicle and a current driving mode, and judging whether the inter-axle active distribution torque mode meets a first preset activation condition by utilizing the first threshold value so as to determine a target torque of at least one driving axle when the inter-axle active distribution torque mode meets the first preset activation condition;

if the torque distribution mode is the inter-wheel active torque distribution feedforward adjustment mode, determining a target torque of the at least one driving wheel according to an actual attachment coefficient of the road, an actual speed of the vehicle, a current steering wheel angle, a current rear axle slip angle and a second threshold value of a vehicle emergency factor, and judging whether the inter-wheel active torque distribution feedforward adjustment mode meets a second preset activation condition by utilizing the second threshold value, so that the inter-wheel active torque distribution feedforward adjustment mode meets the second preset activation condition;

and if the torque distribution mode is the inter-wheel torque distribution feedback adjustment mode, determining whether the inter-wheel torque distribution feedback adjustment mode meets a third preset activation condition according to a third threshold value of the actual attachment coefficient of the road, the actual speed of the vehicle, the current steering wheel rotation angle, the current rear axle side deflection angle and the vehicle emergency factor, and determining the target torque of the at least one driving wheel when the inter-wheel torque distribution feedback adjustment mode meets the third preset activation condition.

Through the technical scheme, the corresponding correction coefficient can be determined according to the torque distribution mode so as to correct the yaw torque of the driving shaft or the driving wheels, so that the limit torque determined based on the yaw torque can accord with the current steering working condition of the vehicle, and the steering stability of the vehicle is ensured.

With reference to the first aspect, in some possible implementations, the determining the target torque of the at least one drive shaft or the at least one drive wheel includes:

determining a base split torque ratio of a rear drive axle of the at least one drive axle;

obtaining a basic change proportion of the rear drive shaft based on a yaw rate difference of the vehicle;

obtaining a rear drive shaft change ratio based on an actual vehicle speed of the vehicle and an actual attachment coefficient of the road;

subtracting the change proportion of the rear driving shaft from the basic distribution proportion to obtain the current demand distribution proportion of the rear driving shaft;

multiplying the whole vehicle torque of the vehicle by the demand distribution proportion of the rear driving shaft to obtain the target torque of the rear driving shaft;

obtaining an original target torque of the driving wheels according to the current torque difference between the left driving wheel and the right driving wheel in the at least one driving wheel;

And obtaining a real torque difference of the driving wheels according to the target yaw moment of the vehicle, and obtaining target torques of the left driving wheel and the right driving wheel based on the real torque difference and the original target torque.

According to the technical scheme, the real torque difference of the driving wheels can be obtained according to the target yaw moment, and the target torque of the left driving wheel and the right driving wheel is obtained by distributing the original target torque of the driving wheels and the real torque difference of the driving wheels through the shaft.

With reference to the first aspect, in some possible implementations, the emergency factor is derived from at least one of a yaw moment, an actual vehicle speed and a driving mode of the vehicle, and a road surface attachment coefficient of a road on which the vehicle is currently located.

According to the technical scheme, the factors can be obtained from various data, so that the numerical value of the torque variation of the rear driving shaft determined based on the factors is more accurate.

In a second aspect, there is provided a distributed torque distribution device for a vehicle, the device comprising:

the identification module is used for identifying the current steering working condition of the vehicle in the process that the vehicle is in the four-wheel drive mode distributed driving;

the calculation module is used for acquiring the actual yaw rate of the vehicle under the condition that the current steering working condition is an understeer working condition or an oversteer working condition, and determining a torque distribution mode of the vehicle according to the speed value of the actual yaw rate and the speed difference value or the speed change rate between the actual yaw rate and the target yaw rate;

And a distribution module for calculating a target torque of at least one drive shaft or at least one drive wheel of the vehicle in the understeer condition or the oversteer condition, respectively, based on the torque distribution mode.

With reference to the second aspect and the foregoing implementation manner, in some possible implementation manners, the method further includes:

a first determination module configured to determine whether a target torque of the at least one drive shaft is greater than a corresponding first maximum limit torque;

and the first output module is used for controlling the output of the corresponding driving shaft according to the first maximum limiting torque when the first maximum limiting torque is larger than the corresponding first maximum limiting torque, obtaining a first exceeding torque according to the target torque and the first maximum limiting torque, attenuating the first exceeding torque according to a first preset attenuation proportion, obtaining a first attenuation torque, and transferring the first attenuation torque to another driving shaft outside the corresponding driving shaft for output.

a second judging module for judging whether the target torque of the at least one driving wheel is greater than a corresponding second maximum limiting torque;

And the second output module is used for controlling the output of the corresponding driving wheel according to the second maximum limiting torque when the second maximum limiting torque is larger than the corresponding second maximum limiting torque, obtaining a second exceeding torque according to the target torque and the second maximum limiting torque, attenuating the second exceeding torque according to a second preset attenuation proportion to obtain a second attenuation torque, and transferring the second attenuation torque to the output torque of the other driving wheel coaxial with the corresponding driving wheel.

With reference to the second aspect and the foregoing implementation manner, in some possible implementation manners, the computing module includes:

an acquisition unit configured to acquire a yaw moment of the vehicle;

the first calculation unit is used for actively distributing the torque among the shafts in the torque distribution mode under the condition that the yaw moment is larger than a first preset threshold value;

a second calculation unit configured to, in a case where an absolute value of a difference between a rate of change of the actual yaw rate and a rate of change of the target yaw rate is greater than a second preset threshold, the torque distribution mode being an inter-wheel active torque distribution feedforward adjustment mode;

and a third calculation unit configured to, in a case where an absolute value of a 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.

With reference to the second aspect and the foregoing implementation manner, in some possible implementation manners, the allocation module includes:

a first judging unit, configured to determine a first threshold value of a yaw moment according to an actual attachment coefficient of a road, a current rear axle slip angle of the vehicle, and a current driving mode when the torque distribution mode is the inter-axle active distribution torque mode, and judge whether the inter-axle active distribution torque mode meets a first preset activation condition by using the first threshold value, so as to determine a target torque of the at least one driving axle when the inter-axle active distribution torque mode meets the first preset activation condition;

a second judging unit configured to determine a second threshold value of a yaw rate variation rate difference value according to an actual attachment coefficient of the road, an actual vehicle speed of the vehicle, a current steering wheel angle, the current rear axle slip angle, and a vehicle emergency factor when the torque distribution mode is the inter-wheel active torque distribution feedforward adjustment mode, and judge whether the inter-wheel active torque distribution feedforward adjustment mode meets a second preset activation condition by using the second threshold value, so as to determine a target torque of the at least one driving wheel when the inter-wheel active torque distribution feedforward adjustment mode meets the second preset activation condition;

And a third judging unit configured to determine a third threshold value of a yaw rate variation difference value according to an actual attachment coefficient of the road, an actual vehicle speed of the vehicle, 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 judge whether the inter-wheel torque distribution feedback adjustment mode meets a third preset activation condition by using the third threshold value, so as to determine a target torque of the at least one driving wheel when the inter-wheel torque distribution feedback adjustment mode meets the third preset activation condition.

With reference to the second aspect and the foregoing implementation manner, in some possible implementation manners, the allocation module is configured to:

With reference to the second aspect and the foregoing implementation manner, in some possible implementation manners, the emergency factor is obtained from at least one of a yaw moment, an actual vehicle speed and a driving mode of the vehicle, and a road surface adhesion coefficient of a road on which the vehicle is currently located.

In a third aspect, there is provided a vehicle comprising: a memory, a processor and a computer program stored on the memory and executable on the processor, the processor executing the program to implement the method of the first aspect or any one of the possible implementation manners of the first aspect.

In a fourth aspect, a computer readable storage medium is provided, the computer readable storage medium storing computer program code which, when run on a computer, causes the computer to perform the method of the first aspect or any one of the possible implementations of the first aspect.

Drawings

FIG. 1 is a flow chart of a method for distributed torque distribution for a vehicle according to an embodiment of the present application;

FIG. 2 is a schematic diagram of a shaft end, wheel end torque distribution flow according to one embodiment of the present application;

FIG. 3 is a schematic diagram of a wheelbase drive torque distribution flow according to one embodiment of the present application;

FIG. 4 is a schematic diagram of a wheel end drive torque distribution flow according to one embodiment of the present application;

FIG. 5 is a schematic illustration of the distribution flow of the rear drive axle inside and outside drive wheels during understeer conditions in accordance with one embodiment of the present application;

FIG. 6 is a schematic diagram of a flow chart for obtaining a true differential of the front axle wheel end torque according to an embodiment of the present application;

FIG. 7 is a schematic illustration of a front drive axle inside and outside drive wheel distribution flow according to one embodiment of the present application;

FIG. 8 is a schematic structural diagram of a distributed torque distribution device for a vehicle according to an embodiment of the present application;

fig. 9 is a schematic structural diagram of a vehicle according to an embodiment of the present application.

Detailed Description

The technical scheme of the application will be clearly and thoroughly described below with reference to the accompanying drawings. Wherein, in the description of the embodiments of the present application, unless otherwise indicated, "/" means or, for example, a/B may represent a or B: the text "and/or" is merely an association relation describing the associated object, and indicates that three relations may exist, for example, a and/or B may indicate: the three cases where a exists alone, a and B exist together, and B exists alone, and furthermore, in the description of the embodiments of the present application, "plural" means two or more than two.

The terms "first," "second," and the like, are used below for descriptive purposes only and are not to be construed as implying or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature.

Fig. 1 is a schematic flow chart of a distributed torque distribution method of a vehicle according to an embodiment of the present application.

Exemplary, as shown in fig. 1, the distributed torque distribution method of the vehicle includes the steps of:

in step S101, during distributed driving of the vehicle in the four-wheel drive mode, a current steering condition of the vehicle is identified.

In the four-wheel drive mode, the front wheels and the rear wheels of the vehicle have driving forces, and the output torque of the motor can be distributed on all the front wheels and the rear wheels according to different proportions according to different running road surface conditions so as to improve the running capability of the vehicle.

In the embodiment of the application, when the vehicle is in the four-wheel drive mode distributed driving process, the current steering working condition of the vehicle can be identified through the relevant parameters of the vehicle, for example, the embodiment of the application can acquire the corner parameters fed back by the steering wheel corner sensor, the actual yaw rate of the vehicle acquired by the yaw rate sensor and the current accelerator pedal opening signal of the vehicle acquired by the pedal opening sensor, so that the current steering working condition of the vehicle can be identified based on the parameters, wherein the current steering working condition can comprise a normal steering working condition, an understeer working condition, an oversteer working condition and the like.

In step S102, in the case where the current steering condition is an understeer condition or an oversteer condition, an actual yaw rate of the vehicle is acquired, and a torque distribution pattern of the vehicle is determined according to a speed value of the actual yaw rate, a speed difference from the target yaw rate, or a speed change rate.

It will be appreciated that when the steering condition is either an understeer condition or an oversteer condition, the current torque of the vehicle is insufficient to ensure that the vehicle is achieving stable steering, and therefore, torque redistribution is required during either the understeer condition or the oversteer condition.

At this time, the embodiment of the present application may acquire the actual yaw rate of the vehicle, and determine the torque distribution mode of the vehicle according to 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, and a specific determination manner is exemplified below.

Alternatively, in one embodiment of the present application, determining the torque distribution pattern of the vehicle from the speed value of the actual yaw rate, the speed difference value from the target yaw rate, or the speed change rate includes: acquiring the yaw moment of the vehicle; under the condition that the yaw moment is larger than a first preset threshold value, the torque distribution mode is an inter-axle active torque distribution mode; the torque distribution mode is an inter-wheel active torque distribution feedforward adjustment mode under the condition that the absolute value of the difference value between the change rate of the actual yaw rate and the change rate of the target yaw rate is larger than a second preset threshold value; in the case where the absolute value of the difference between the target yaw rate and the actual yaw rate is greater than the third preset threshold value, the torque distribution mode is an inter-wheel torque distribution feedback adjustment mode.

In some embodiments, the embodiment of the application can determine that the vehicle enters the four-wheel-drive mode distributed driving mode by combining parameters such as a vehicle speed, a total torque demand, a steering wheel angle and the like and by combining the angle after the falling edge function, at this time, the basic torque distribution function is activated, that is, when the vehicle speed is greater than a certain value, the total required torque is greater than a certain value, the steering wheel angle is greater than a certain value, and the angle is ensured to be still greater than a certain value within a certain time when the falling edge function ensures that the angle is smaller than a certain value, the vehicle enters the four-wheel-drive mode distributed driving mode, and the basic torque distribution function is activated, wherein the certain value can be correspondingly set by a person skilled in the art according to actual conditions, or can be obtained by looking up a table by referring to the vehicle speed, and a real and false calibration quantity debugwindow can be reserved in the basic torque distribution function window, so that when the calibration quantity is 0, at this time, the embodiment of the application can not distribute the torque, and directly output the distribution value under the mode.

Further, the embodiment of the application can activate the basic torque distribution function when the yaw moment of the vehicle exceeds a certain set value, and determine the torque distribution mode as an inter-axle active torque distribution mode. The first preset threshold value may be an upper limit value of the activation interval, when the yaw moment exceeds the upper limit value, a basic torque distribution function may be activated, and it is determined that the torque distribution mode is an inter-axle active torque distribution mode, and when the above function is activated, the above function is turned off only when the yaw moment is less than the lower limit value.

The embodiment of the application can also determine that the torque distribution mode is an inter-wheel active torque distribution feedforward adjustment mode when the absolute value of the difference value between the actual yaw rate change rate and the target yaw rate change rate is larger than a certain set value and the basic torque distribution function is activated. The set value, namely the second preset threshold value, can refer to the vehicle speed for table lookup, and is corrected according to the attachment coefficient, the vehicle speed, the steering wheel angle, the rear axle slip angle and the correction coefficient obtained by table lookup of the vehicle emergency factor.

The embodiment of the application can also determine that the torque distribution mode is an inter-wheel active torque distribution feedforward adjustment mode when the absolute value of the difference value between the target yaw rate and the actual yaw rate is larger than a certain set value and the basic torque distribution function is activated. The setting value, namely the third preset threshold value, can refer to the vehicle speed for table lookup, and is corrected according to the attachment coefficient, the vehicle speed, the steering wheel angle, the rear axle slip angle and the correction coefficient obtained by table lookup of the vehicle emergency factor.

Through the activation of the corresponding torque distribution mode, the embodiment of the application can judge when to trigger the active reduction or the active lifting of the yaw torque so as to ensure the steering stability of the vehicle.

In step S103, a target torque of at least one drive shaft or at least one drive wheel of the vehicle in an understeer condition or an oversteer condition, respectively, is calculated based on the torque distribution pattern.

In an actual implementation process, the embodiment of the application can calculate the target torque of the driving shaft or the driving wheel of the vehicle under different steering working conditions based on the corresponding torque distribution mode.

That is, the embodiment of the application can calculate the target torque of at least one driving shaft of the vehicle under the understeer working condition or the oversteer working condition respectively in the inter-axle active torque distribution mode; according to the method and the device for calculating the target torque of the at least one driving wheel of the vehicle under the understeer working condition or the oversteer working condition respectively in the inter-wheel active torque distribution feedforward adjustment mode or the inter-wheel active torque distribution feedforward adjustment mode.

Optionally, in one embodiment of the application, calculating the target torque of the at least one drive axle or the at least one drive wheel of the vehicle in an understeer condition or an oversteer condition, respectively, based on the torque distribution pattern, comprises: if the torque distribution mode is an inter-axle active distribution torque mode, determining a first threshold value of yaw moment according to an actual attachment coefficient of a road, a current rear axle slip angle of a vehicle and a current driving mode, and judging whether the inter-axle active distribution torque mode meets a first preset activation condition by utilizing the first threshold value so as to determine target torque of at least one driving axle when the inter-axle active distribution torque mode meets the first preset activation condition; if the torque distribution mode is an inter-wheel active torque distribution feedforward adjustment mode, determining a second threshold value of a yaw rate change rate difference value according to an actual attachment coefficient of a road, an actual vehicle speed of a vehicle, a current steering wheel angle, a current rear axle slip angle and a vehicle emergency factor, and judging whether the inter-wheel active torque distribution feedforward adjustment mode meets a second preset activation condition by utilizing the second threshold value so as to determine target torque of at least one driving wheel when the inter-wheel active torque distribution feedforward adjustment mode meets the second preset activation condition; if the torque distribution mode is an inter-wheel torque distribution feedback adjustment mode, a third threshold value of a yaw rate change difference value is determined according to an actual attachment coefficient of a road, an actual speed of a vehicle, a current steering wheel rotation angle, a current back shaft side deflection angle and a vehicle emergency factor, whether the inter-wheel torque distribution feedback adjustment mode meets a third preset activation condition is judged by utilizing the third threshold value, and when the inter-wheel torque distribution feedback adjustment mode meets the third preset activation condition, target torque of at least one driving wheel is determined.

In the actual execution process, the embodiment of the application can perform feedforward and feedback torque distribution according to the change of the yaw rate, and the following is an explanation of calculation of target torque under different steering working conditions, wherein the target torque of the driving shaft is the driving torque of the driving shaft, and the target torque of the driving wheel is the driving torque of the driving wheel.

When the torque distribution mode is an inter-axle active distribution torque mode, the embodiment of the application can obtain the threshold value corresponding to the inter-axle active distribution torque mode through dynamic parameters such as the actual attachment coefficient of a road, the current rear axle side deflection angle of a vehicle, the current driving mode and the like, wherein the threshold value can comprise the upper limit value and the lower limit value of the yaw moment, so that whether the inter-axle active distribution torque mode meets the first preset activation condition or not is judged according to the upper limit value, the lower limit value and the current yaw moment of the vehicle, the axle distribution is further determined to be in the opening/closing threshold, when the inter-axle active distribution torque mode meets the first preset activation condition, the axle distribution activation is carried out, the corresponding function is triggered, the corresponding torque distribution is carried out subsequently, and the target torque of at least one driving axle is finally determined.

Similarly, when the torque distribution mode is an inter-wheel active torque distribution feedforward adjustment mode, the embodiment of the application can obtain the threshold value corresponding to the inter-wheel active torque distribution feedforward adjustment mode through dynamic parameters such as an actual attachment coefficient of a road, an actual speed of a vehicle, a current steering wheel angle, a current rear axle side deflection angle, a vehicle emergency factor and the like, wherein the threshold value can comprise an upper limit value of a yaw rate change rate and a lower limit value of the yaw rate change rate, so that whether the inter-wheel active torque distribution feedforward adjustment mode meets a second preset activation condition or not is judged according to a difference value of the upper limit value, the lower limit value and the current yaw rate change rate, and then the wheel distribution is determined to be in an opening/closing threshold, so that when the second preset activation condition is met, the wheel distribution activation is carried out, corresponding functions are triggered, so that corresponding torque distribution is carried out later, and finally the target torque of at least one driving wheel is determined.

When the torque distribution mode is an inter-wheel torque distribution feedback adjustment mode, the embodiment of the application can obtain the threshold value corresponding to the inter-wheel torque distribution feedback adjustment mode through dynamic parameters such as an actual attachment coefficient of a road, an actual speed of a vehicle, a current steering wheel angle, a current rear axle slip angle, a vehicle emergency factor and the like, wherein the threshold value can comprise an upper limit value of a yaw rate change difference value and a lower limit value of a yaw rate difference value, so that whether the inter-wheel torque distribution feedback adjustment mode meets a third preset activation condition or not is judged according to the upper limit value, the lower limit value and the current yaw rate change difference value, and further, the wheel distribution is determined to be in an on/off threshold, so that when the third preset activation condition is met, the wheel distribution activation is carried out, corresponding functions are triggered, so that corresponding torque distribution is carried out later, and finally, the target torque of at least one driving wheel is determined.

For example, under understeer conditions:

the feedback torque when the actual yaw and the target yaw are different to calculate the understeer working condition, the yaw torque can be obtained through the yaw rate and inertia, the feedback is controlled and regulated by a PID (proportion-integral-derivative) controller, the steady-state deviation is eliminated, the quick response is ensured, the feedback torque can be further modified according to the attachment coefficient, the vehicle speed, the yaw difference and the driving mode, and the proportion-integral-derivative of the PID controller is further modified;

the feedforward torque in the understeer working condition is calculated by the difference value between the actual yaw and the target yaw, and the yaw torque can be obtained by table lookup of the road surface adhesion coefficient, the vehicle speed and the difference value between the actual yaw rate and the target yaw rate, or the yaw torque can be obtained by table lookup of the road surface adhesion coefficient, the vehicle speed and the difference value between the actual yaw rate and the target yaw rate.

Under oversteer conditions:

the feedback torque when the actual yaw and the target yaw are in the oversteer condition is calculated, the yaw torque can be obtained through the yaw rate and inertia, the feedback is controlled and regulated by the PID controller, the steady-state deviation is eliminated, the quick response is ensured, the feedback torque can be further modified according to the attachment coefficient, the vehicle speed, the yaw difference and the driving mode, and the proportional-integral-derivative of the PID controller is further modified;

Yaw compensation of the feedback torque by adding the change of the rear axle side deflection angle is increased;

the feedforward torque when the actual yaw and the target yaw difference calculate the oversteer condition can be obtained by table lookup of road surface adhesion coefficient, vehicle speed and the difference between the actual yaw and the target yaw speed, or can be obtained by table lookup of road surface adhesion coefficient, vehicle speed and the difference between the actual yaw speed and the target yaw speed.

Optionally, in one embodiment of the application, determining the target torque of the at least one drive shaft or the at least one drive wheel comprises: determining a base split torque ratio of a rear drive axle of the at least one drive axle; obtaining a basic change proportion of a rear driving shaft based on a yaw rate difference of the vehicle; obtaining a rear drive shaft change ratio based on the actual speed of the vehicle and the actual attachment coefficient of the road; subtracting the change proportion of the rear driving shaft from the basic distribution proportion to obtain the current demand distribution proportion of the rear driving shaft; multiplying the whole vehicle torque of the vehicle by the demand distribution proportion of the rear driving shaft to obtain the target torque of the rear driving shaft; obtaining an original target torque of the driving wheels according to the current torque difference between the left driving wheel and the right driving wheel in the at least one driving wheel; obtaining a real torque difference of a driving wheel according to a target yaw moment of the vehicle, and obtaining target torques of a left driving wheel and a right driving wheel based on the real torque difference and an original target torque; wherein the emergency factor is derived from at least one of a yaw moment, an actual vehicle speed and a driving pattern of the vehicle and a road surface attachment coefficient of a road on which the vehicle is currently located.

As shown in fig. 2, the embodiment of the present application may perform wheelbase driving torque distribution or wheel end driving torque distribution after the torque distribution function is activated, the yaw moment is calculated, and the factors are combined.

The emergency factor can evaluate the emergency factor of the vehicle according to the yaw, the speed and the road surface adhesion change of the vehicle, and reasonably correct the torque distribution. For example, the target yaw force and the actual yaw difference value can be used for checking up to obtain an emergency factor, the understeer degree is used for checking up to obtain an emergency factor, the oversteer degree is used for checking up to obtain an emergency factor, and the emergency factor is corrected by accumulation, vehicle speed, road surface adhesion and driving mode.

In the aspect of inter-axle driving torque distribution, as a possible implementation manner, as shown in fig. 3, the embodiment of the application can realize inter-axle driving torque distribution according to the rear driving axle distribution proportion, the real transfer torque proportion determined by the post-attenuation transfer ratio, the required torque after each axle is subjected to the post-attenuation transfer through axle torque judgment, and the wheel end required torque after the axle distribution is subjected to the axle distribution and the current wheel end torque after the axle distribution.

Specifically, the method may include the steps of:

s1: the rear drive shaft is proportioned. And according to the distribution proportion of the rear driving shaft, the real transfer torque proportion determined by the transfer proportion after attenuation, and the required torque after the attenuation transfer of each shaft is judged by the shaft torque, the current wheel end torque after the shaft distribution is adopted, and the wheel end required torque after the shaft distribution is adopted.

The embodiment of the application can judge the distribution torque proportion of the rear driving shaft according to the difference value of the target yaw and the actual yaw of the vehicle, define the difference value of the target yaw and the actual yaw to be a, define the difference value of the maximum calibration to be b and the difference value of the maximum calibration to be b, temporarily set the a ratio b as the basic change quantity of the torque of the rear driving shaft, and obtain the change correction quantity of the torque of the rear driving shaft through the table look-up of the vehicle speed and the road surface adhesion, thereby obtaining the change quantity c of the torque of the rear driving shaft.

Under the condition that the current steering working condition is an understeer working condition, the rear driving shaft needs to be added with torque, and the rear driving shaft basic distribution ratio can be added with the rear driving shaft torque change ratio to obtain the rear driving shaft demand distribution ratio;

and under the condition that the current steering working condition is oversteering working condition, the rear driving shaft needs to reduce torque, and the rear driving shaft demand distribution ratio can be obtained by subtracting the shaft torque change ratio from the rear driving shaft basic distribution ratio.

It should be noted that, the change of the demand ratio of the rear driving axle needs to ensure that the inter-axle torque distribution function is in an activated state, and the demand ratio from the basic distribution ratio of the rear driving axle to the demand distribution ratio of the rear driving axle needs to be smoothly and excessively processed and output after being limited by the upper limit and the lower limit.

S2: torque transfer ratio after decay. In the embodiment of the application, during the process of actively reducing or lifting the yaw torque, the distributed torque may exceed the limit torque during the process of redistributing the axle end or wheel end torque, and the torque exceeding the limit part is attenuated and then transferred to another driving axle or driving wheel. When the difference value between the target yaw and the actual yaw reaches a certain value and the vehicle has a certain speed and no rudder reversing trigger is carried out, the rudder reversing is defined as the fact that the multiplication of the target yaw and the actual yaw is smaller than zero, and the transfer proportion calculation after the attenuation is activated. After a certain correction amount is subtracted from the target yaw rate, the ratio of the obtained value to the actual yaw rate is subjected to first-order low-pass filtering and then is subjected to road surface adhesion table lookup, and the attenuated transfer proportion of the front driving shaft, the rear driving shaft and the single driving wheel can be obtained respectively.

S3: and judging the axle torque. The whole vehicle demand torque is multiplied by the rear drive shaft demand torque distribution ratio to obtain rear drive shaft demand torque, the rear drive shaft demand torque minus the rear drive shaft limit torque is rear drive shaft roll-out torque, the front drive shaft demand torque is the whole vehicle demand torque minus the rear drive shaft demand torque, and the front drive shaft demand torque minus the front drive shaft limit torque is front drive shaft roll-out torque.

When the steering is in the understeer working condition, the rear driving shaft increases the torque, and when the rear driving shaft increases beyond the limit of the rear driving shaft, the rear driving shaft rotates out of the torque and multiplies the transfer ratio of the rear driving shaft after attenuation, so that the rear driving shaft increases. The front drive axle increase plus the front drive axle demand torque is limited by the maximum torque capacity to the front drive axle final demand torque, and the rear drive axle demand torque is limited by the maximum torque capacity to the rear drive axle final demand torque.

The front drive axle increases torque during oversteering conditions, and the front drive axle increases beyond the front drive axle capacity limit by multiplying the front drive axle roll-out torque by the front drive axle attenuated transfer ratio. The rear drive axle increase plus the rear drive axle demand torque is limited by the maximum torque capacity to the rear drive axle final demand torque, and the front drive axle demand torque is limited by the maximum torque capacity to the front drive axle final demand torque.

S4: the axle distributes the rear current wheel end torque. The principle of wheel distribution is that the torque of an outer driving wheel is increased more when the steering is under the working condition, the torque of an inner driving wheel is increased more when the steering is over, the wheels with increased torque can roll out the torque according to the maximum torque limiting capacity, and the roll-out part can attenuate a part and then roll to another wheel.

The distribution method comprises the following steps:

the axle demand torque is divided by 2 to be the original target torque of the driving wheel outside the current driving axle after the torque difference between the left driving wheel and the right driving wheel of the current driving axle is added, and the original target torque of the driving wheel outside the current driving axle is subtracted by the torque difference between the left driving wheel and the right driving wheel of the current driving axle to be the original target torque of the driving wheel inside the current driving axle. The original target torque is required to be limited by the limit torque capacity and then output as original target torque 1, and the original target torque minus the original target torque 1 is the wheel end turning torque. The transfer ratio of the outer drive wheel out torque multiplied by the single wheel decay is the actual out torque of the outer drive wheel to the inner drive wheel. The original target torque 1 of the inner driving wheel is added with the actual torque to be the original target torque 2 of the inner driving wheel, and the original target torque 2 of the inner driving wheel is output to be the original target torque 3 of the inner driving wheel through the limitation of the maximum torque capacity.

The transfer ratio of the inner drive wheel out torque multiplied by the single wheel decay is the actual out torque of the inner drive wheel to the outer drive wheel. The outer driving wheel original target torque 1 plus the actual roll-out torque is the outer driving wheel original target torque 2, and the outer driving wheel original target torque 2 is limited to the outer driving wheel original target torque 3 through the maximum torque capacity. When the inter-axle active torque distribution module is activated, the current wheel end torque to the wheel end original target torque 3 is required to be smoothly and excessively output.

In terms of wheel end driving torque redistribution, the embodiment of the application can determine the left-right side torque distribution difference according to the target yaw torque converted by converting the yaw torque to the driving torque distribution difference. And obtaining the required torque of the wheel end according to the torque difference between the left driving wheel and the right driving wheel, the torque of the outer wheel after shaft distribution and the damping transfer proportion. And then filtering smoothly and excessively through arbitration judgment, compensating, and filtering smoothly and excessively again to obtain the required wheel end driving torque, namely the target torque of at least one driving wheel.

For example, as shown in fig. 4, the wheel end drive torque distribution may include the steps of:

s1: the yaw torque scales the drive torque distribution difference. According to the embodiment of the application, the target yaw moment can be divided by the wheel track multiplied by the rolling radius sum of the front wheel and the rear wheel to obtain the original value of the driving torque difference on the left side and the right side, and the driving torque distribution difference on the left side and the right side is corrected by table lookup through the road adhesion coefficient, the vehicle speed and the emergency factor to obtain the preprocessing driving torque distribution difference. And the compensation value of the left and right driving torque distribution difference values is obtained through the total driving torque table lookup, and after the compensation value of the driving torque distribution difference value is added with the preprocessing driving torque distribution difference value, the left and right driving torque distribution difference values are output through the limitation of the maximum and minimum driving torque distribution difference values and the first-order low-pass filtering. The slope of the left and right side drive torque distribution difference variation can also be defined by calibration time and first order low pass filtering.

S2: wheel end drive torque distribution calculation. 5-7, wherein FIG. 5 is a schematic diagram of the distribution flow of the inner and outer driving wheels of the rear driving shaft under the understeer condition, and FIG. 6 is a schematic diagram of the acquisition flow of the true variation difference of the front driving shaft wheel end torque; fig. 7 is a schematic view of the front drive axle inside and outside drive wheel distribution flow.

Specifically, under-steer conditions, the outer drive wheel lifts torque and the inner drive wheel reduces torque. Since the rear drive axle drive torque is greater than the front drive axle, the rear drive axle allocation priority principle, the left-right drive torque allocation difference may be tentative as the rear drive axle left-right drive torque allocation difference when calculating the rear drive axle allocation. The left-right side torque distribution difference value of the rear driving shaft is divided by 2 to be the single-wheel variable quantity of the rear driving shaft, the external-side wheel torque distributed by the rear driving shaft plus the single-wheel variable quantity is the original demand quantity distributed by the external-side wheel end of the rear driving shaft, the original torque distributed by the external-side wheel end of the rear driving shaft minus the limited quantity of the external-side wheel torque of the rear driving shaft is the original external-side wheel end rotating quantity of the rear driving shaft, and the rotating quantity multiplied by the single-wheel attenuation rear transfer proportion is the real rotating quantity of the external driving wheel of the rear driving shaft to the internal driving wheel. The change quantity is subtracted from the inner side wheel torque distributed by the rear driving shaft to distribute original demand quantity for the inner side wheel end of the rear driving shaft, the original demand quantity distributed by the inner side wheel end of the rear driving shaft is limited by the maximum torque, the real rotation quantity of the outer driving wheel of the rear driving shaft to the inner driving wheel is added, and the output is the inner side demand torque of the wheel end of the rear driving shaft after the maximum torque limitation. The outer side wheel end of the rear driving shaft distributes original torque, adds the rotation quantity after the inner side torque of the rear driving shaft is limited, and outputs the rotation quantity to the outer side required torque of the wheel end of the rear driving shaft after the maximum torque limitation.

The required torque of the outer driving wheels at the rear driving shaft wheel end minus the required torque of the inner driving wheels of the rear driving shaft is the actual required variation of the inner driving wheels and the outer driving wheels of the rear driving shaft, the torque of the outer driving wheels distributed by the rear driving shaft minus the torque of the inner driving wheels distributed by the rear driving shaft is the current variation of the inner driving wheels and the outer driving wheels of the rear driving shaft, and the former minus the rear driving shaft is the actual variation difference of the torque of the rear driving shaft under the action of yaw moment. The difference obtained by subtracting the real change amount of the torque of the rear drive shaft from the left and right side distribution torque difference is the real change amount difference of the torque of the front drive shaft.

And when the steering is under the working condition, the inner and outer driving wheels of the front driving shaft are distributed. The real change difference value of the front driving shaft torque is divided by 2 to be the single-wheel change quantity of the front driving shaft, the external-side wheel torque after front driving shaft distribution plus the single-wheel change quantity is the original demand quantity distributed to the external-side wheel end of the front driving shaft, the original torque distributed to the external-side wheel end of the front driving shaft minus the limited quantity of the external-side wheel torque of the front driving shaft is the original external-side wheel end rotating quantity of the front driving shaft, and the rotating quantity is multiplied by the single-wheel attenuation rear transfer proportion to be the real rotating quantity of the external driving wheel of the front driving shaft to the internal driving wheel. The inner side wheel torque after the front driving shaft is distributed minus the variable quantity is the original demand quantity distributed to the inner side wheel end of the front driving shaft, the original demand quantity distributed to the inner side wheel end of the front driving shaft is limited by the maximum torque, the real rotation quantity of the outer driving wheel of the front driving shaft to the inner driving wheel is added, and the output is the inner side demand torque of the wheel end of the front driving shaft after the maximum torque limitation. The outer side wheel end of the front driving shaft distributes original torque, adds the rotation quantity of the inner side torque of the front driving shaft after limiting, and outputs the rotation quantity to the outer side required torque of the wheel end of the front driving shaft after limiting the maximum torque.

And under the oversteer condition, the outer driving wheel reduces the torque, and the inner driving wheel improves the torque. The left-right side torque distribution difference value of the rear driving shaft is divided by 2 to be the single-wheel variable quantity of the rear driving shaft, the inner side wheel torque distributed by the rear driving shaft plus the single-wheel variable quantity is the original demand quantity distributed by the inner side wheel end of the rear driving shaft, the original torque distributed by the inner side wheel end of the rear driving shaft minus the inner side wheel torque limiting quantity of the rear driving shaft is the original inner side wheel end rotating quantity of the rear driving shaft, and the rotating quantity multiplied by the single-wheel attenuation rear transfer proportion is the real rotating quantity of the inner driving wheel of the rear driving shaft to the outer driving wheel. The external side wheel torque after the rear driving shaft is distributed minus the variable quantity is the original demand quantity distributed to the external side wheel end of the rear driving shaft, the original demand quantity distributed to the external side wheel end of the rear driving shaft is limited by the maximum torque, the real rotation quantity of the driving wheel in the rear driving shaft to the external driving wheel is added, and the external side demand torque of the wheel end of the rear driving shaft is output after the maximum torque limitation. The inner side wheel end of the rear driving shaft distributes original torque, adds the rotation quantity after the torque limitation of the outer side of the rear driving shaft, and outputs the rotation quantity to the inner side required torque of the wheel end of the rear driving shaft after the maximum torque limitation.

And when the steering is in an oversteer condition, the inner and outer driving wheels of the front driving shaft are distributed. The left-right side torque distribution difference value of the front driving shaft is divided by 2 to be the single-wheel variable quantity of the front driving shaft, the inner side wheel torque distributed by the front driving shaft is added with the single-wheel variable quantity to be the original demand quantity distributed by the inner side wheel end of the front driving shaft, the original torque distributed by the inner side wheel end of the front driving shaft is subtracted by the inner side wheel torque limiting quantity of the front driving shaft to be the original inner side wheel end rotating quantity of the front driving shaft, and the rotating quantity is multiplied by the single-wheel attenuation rear transfer proportion to be the real rotating quantity of the inner driving wheel of the front driving shaft to the outer driving wheel. The external side wheel torque after the front driving shaft is distributed minus the variable quantity is the original demand quantity distributed to the external side wheel end of the front driving shaft, the original demand quantity distributed to the external side wheel end of the front driving shaft is limited by the maximum torque, the real rotation quantity of the driving wheel in the front driving shaft to the external driving wheel is added, and the external side demand torque is output to the external side of the wheel end of the front driving shaft after the maximum torque is limited. The inner side wheel end of the front driving shaft distributes original torque, adds the rotation quantity after the torque limitation of the outer side of the front driving shaft, and outputs the rotation quantity to the inner side required torque of the wheel end of the front driving shaft after the maximum torque limitation.

S3: and (5) arbitration judgment. In some embodiments, when the wheel end required torque when the vehicle turns left to the wheel end required torque when turning right is required to be smooth and excessive, the smooth and excessive time can be obtained by looking up a table of the change slope of the torque difference between the current left and right driving wheels, and when the steering wheel angle change speed is greater than a certain value and the difference between the target and the actual yaw angle is greater than a certain value, the wheel end required torque is compensated, and the torque change is smooth and excessive. The wheel end torque after the inter-axle distribution is changed into the wheel end torque after the wheel end driving redistribution, and the trigger condition is that the inter-wheel active torque distribution is activated.

Optionally, in one embodiment of the present application, further includes: judging whether the target torque of at least one driving shaft is larger than the corresponding first maximum limiting torque; and if the torque is larger than the corresponding first maximum limiting torque, controlling the output of the corresponding driving shaft by using the first maximum limiting torque, obtaining a first exceeding torque according to the target torque and the first maximum limiting torque, attenuating the first exceeding torque by using a first preset attenuation proportion, obtaining a first attenuation torque, and transferring the first attenuation torque to another driving shaft outside the corresponding driving shaft for output.

It will be appreciated that during the active lowering or raising of the yaw torque, the distributed torque may exceed the limit torque during the redistribution of the axle or wheel end torque, that is, the current maximum torque of the drive axle is limited according to the maximum torque, and the torque exceeding the limit may be attenuated and transferred to another drive axle, where the maximum limit torque is a constant value for the same road surface.

In some embodiments, when the difference between the target yaw and the actual yaw reaches a certain value and the vehicle has a certain speed without rudder reversing trigger, rudder reversing is defined herein as the target yaw and the actual yaw multiplied by less than zero, and the transition ratio calculation after the decay is activated. After a certain correction amount is subtracted from the target yaw rate, the ratio of the obtained value to the actual yaw rate is subjected to first-order low-pass filtering and then is subjected to road surface adhesion table lookup, so that the attenuated and transferred proportion of the front driving shaft and the rear driving shaft can be obtained respectively, namely a first preset attenuation proportion is obtained, the first exceeding torque is attenuated by the first preset attenuation proportion, and the corresponding torque is transferred to the output torque of another driving shaft except the corresponding driving shaft according to the attenuation result;

when the target torque of the driving shaft is smaller than the first maximum limiting torque, the embodiment of the application does not need to perform corresponding damping transfer calculation, and the damping transfer can not be triggered under all working conditions, so that corresponding analysis is required according to the actual steering working conditions of the vehicle.

Optionally, in one embodiment of the present application, further includes: judging whether the target torque of at least one driving wheel is larger than the corresponding second maximum limiting torque; and if the torque is larger than the corresponding second maximum limiting torque, controlling the output of the corresponding driving wheel by using the second maximum limiting torque, obtaining a second exceeding torque according to the target torque and the second maximum limiting torque, attenuating the second exceeding torque by using a second preset attenuation proportion, obtaining a second attenuation torque, and transferring the second attenuation torque to the output torque of the other driving wheel coaxial with the corresponding driving wheel.

In other embodiments, after the calculation of the transition proportion after attenuation is activated, the embodiment of the application can obtain the ratio of the numerical value to the actual yaw rate by subtracting a certain correction amount from the target yaw rate, and the ratio can be subjected to first-order low-pass filtering and road surface adhesion table lookup to obtain the transition proportion after attenuation of the front and rear driving shafts respectively, namely a second preset attenuation proportion is obtained, so that the second excessive torque is attenuated by the second preset attenuation proportion, and the corresponding torque is transferred to the output torque of another driving wheel outside the corresponding driving wheel according to the attenuation result;

When the target torque of the driving shaft is smaller than the second maximum limiting torque, the embodiment of the application does not need to perform corresponding damping transfer calculation, and the damping transfer can not be triggered under all working conditions, so that corresponding analysis is required according to the actual steering working conditions of the vehicle.

In summary, the application can obtain the actual yaw rate of the vehicle when the current steering condition of the vehicle is an understeer condition or an oversteer condition in the process that the vehicle is in a four-wheel-drive mode distributed driving, so as to determine the torque distribution mode of the vehicle according to the speed value of the actual yaw rate, the speed difference value between the actual yaw rate and the target yaw rate or the speed change rate, calculate the target torque of at least one driving shaft or at least one driving wheel of the vehicle under the understeer condition or the oversteer condition respectively, and perform torque distribution according to the change of the yaw rate of the vehicle, so as to calculate the target torque under different conditions respectively, thereby actively reducing the yaw torque or improving the yaw torque, improving the understeer condition or the oversteer condition of the vehicle, improving the steering stability of the vehicle and effectively ensuring the safety of the vehicle. Therefore, the problems that when torque is redistributed under understeer working conditions or oversteer working conditions in the related technology, the torque overrun cannot be reasonably distributed, real-time adjustment cannot be carried out according to the vehicle conditions, understeer or oversteer working conditions of the vehicle are difficult to effectively cope with, the steering stability of the vehicle is affected, and serious traffic accidents are even easily caused are solved.

Fig. 8 is a schematic structural diagram of a distributed torque distribution device of a vehicle according to an embodiment of the present application.

For example, as shown in fig. 8, the apparatus 10 may include: an identification module 100, a calculation module 200 and an allocation module 300.

Specifically, the identifying module 100 is configured to identify a current steering condition of the vehicle during the distributed driving of the vehicle in the four-wheel drive mode.

The calculation module 200 is configured to obtain an actual yaw rate of the vehicle when the current steering condition is an understeer condition or an oversteer condition, and determine a torque distribution mode of the vehicle according to a speed value of the actual yaw rate, a speed difference value between the actual yaw rate and the target yaw rate, or a speed change rate.

The distribution module 300 is configured to calculate a target torque of at least one drive axle or at least one drive wheel of the vehicle in an understeer condition or an oversteer condition, respectively, based on the torque distribution mode.

Optionally, in one embodiment of the present application, the distributed torque distribution device 10 of the vehicle further comprises: the device comprises a first judging module and a first output module.

The first judging module is used for judging whether the target torque of at least one driving shaft is larger than the corresponding first maximum limiting torque.

Optionally, in one embodiment of the present application, the distributed torque distribution device 10 of the vehicle further comprises: the device comprises a second judging module and a second output module.

The second judging module is used for judging whether the target torque of at least one driving wheel is larger than the corresponding second maximum limiting torque.

The second output module is used for controlling the output of the corresponding driving wheel according to the second maximum limiting torque when the second maximum limiting torque is larger than the corresponding second maximum limiting torque, obtaining second exceeding torque according to the target torque and the second maximum limiting torque, attenuating the second exceeding torque according to a second preset attenuation proportion, obtaining second attenuation torque, and transferring the second attenuation torque to the output torque of the other driving wheel coaxial with the corresponding driving wheel.

Optionally, in one embodiment of the present application, the computing module 200 includes: an acquisition unit, a first calculation unit, a second calculation unit, and a third calculation unit.

And the acquisition unit is used for acquiring the yaw moment of the vehicle.

The first calculation unit is used for actively distributing the torque between the shafts in the torque distribution mode under the condition that the yaw moment is larger than a first preset threshold value.

And a second calculation unit for, in the case where 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 is greater than a second preset threshold, the torque distribution mode being an inter-wheel active torque distribution feedforward adjustment mode.

Alternatively, in one embodiment of the present application, the distribution module 300 includes: the device comprises a first judging unit, a second judging unit and a third judging unit.

The first judging unit is used for determining a first threshold value of yaw moment according to an actual attachment coefficient of a road, a current back axle side deflection angle of a vehicle and a current driving mode when the torque distribution mode is an inter-axle active distribution torque mode, judging whether the inter-axle active distribution torque mode meets a first preset activation condition or not by utilizing the first threshold value, and determining target torque of at least one driving axle when the inter-axle active distribution torque mode meets the first preset activation condition;

A second judging unit for determining a second threshold value of a yaw rate variation rate difference value according to an actual attachment coefficient of a road, an actual vehicle speed of a vehicle, a current steering wheel angle, a current rear axle slip angle and a vehicle emergency factor when the torque distribution mode is an inter-wheel active torque distribution feedforward adjustment mode, and judging whether the inter-wheel active torque distribution feedforward adjustment mode meets a second preset activation condition by using the second threshold value, so as to determine a target torque of at least one driving wheel when the inter-wheel active torque distribution feedforward adjustment mode meets the second preset activation condition;

and the third judging unit is used for determining a third threshold value of a yaw rate change difference value according to an actual attachment coefficient of a road, an actual speed of a vehicle, a current steering wheel rotation angle, a current rear axle side deflection angle and a vehicle emergency factor when the torque distribution mode is an inter-wheel torque distribution feedback regulation mode, judging whether the inter-wheel torque distribution feedback regulation mode meets a third preset activation condition or not by utilizing the third threshold value, and determining target torque of at least one driving wheel when the inter-wheel torque distribution feedback regulation mode meets the third preset activation condition.

Optionally, in one embodiment of the present application, the allocation module 300 is configured to: determining a base split torque ratio of a rear drive axle of the at least one drive axle; obtaining a basic change proportion of a rear driving shaft based on a yaw rate difference of the vehicle; obtaining a rear drive shaft change ratio based on the actual speed of the vehicle and the actual attachment coefficient of the road; subtracting the change proportion of the rear driving shaft from the basic distribution proportion to obtain the current demand distribution proportion of the rear driving shaft; multiplying the whole vehicle torque of the vehicle by the demand distribution proportion of the rear driving shaft to obtain the target torque of the rear driving shaft; obtaining an original target torque of the driving wheels according to the current torque difference between the left driving wheel and the right driving wheel in the at least one driving wheel; the actual torque difference of the driving wheels is obtained according to the target yaw moment of the vehicle, and the target torques of the left driving wheel and the right driving wheel are obtained based on the actual torque difference and the original target torque.

Optionally, in one embodiment of the application, the factor is derived from at least one of a yaw moment, an actual vehicle speed and a driving pattern of the vehicle and a road surface attachment coefficient of a road on which the vehicle is currently located.

Fig. 9 is a schematic structural view of a vehicle according to an embodiment of the present application. The vehicle may include:

memory 901, processor 902, and a computer program stored on memory 901 and executable on processor 902.

The processor 902 implements the distributed torque distribution method of the vehicle provided in the above embodiment when executing a program.

Further, the vehicle further includes:

a communication interface 903 for communication between the memory 901 and the processor 902.

Memory 901 for storing a computer program executable on processor 902.

The memory 901 may include a high-speed RAM (Random Access Memory ) memory, and may also include a nonvolatile memory, such as at least one magnetic disk memory.

If the memory 901, the processor 902, and the communication interface 903 are implemented independently, the communication interface 903, the memory 901, and the processor 902 may be connected to each other through a bus and perform communication with each other. The bus may be an ISA (Industry Standard Architecture ) bus, a PCI (Peripheral Component, external device interconnect) bus, or EISA (Extended Industry Standard Architecture ) bus, among others. The buses may be divided into address buses, data buses, control buses, etc. For ease of illustration, only one thick line is shown in fig. 9, but not only one bus or one type of bus.

Alternatively, in a specific implementation, if the memory 901, the processor 902, and the communication interface 903 are integrated on a chip, the memory 901, the processor 902, and the communication interface 903 may communicate with each other through internal interfaces.

The processor 902 may be a CPU (Central Processing Unit ) or ASIC (Application Specific Integrated Circuit, application specific integrated circuit) or one or more integrated circuits configured to implement embodiments of the present application.

The present embodiment also provides a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, implements the distributed torque distribution method of a vehicle as above.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present application, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

While embodiments of the present application have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the application, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the application.

Claims

1. A distributed torque distribution method for a vehicle, comprising the steps of:

2. The method as recited in claim 1, further comprising:

3. The method as recited in claim 1, further comprising:

4. The method according to claim 1, wherein the determining the torque distribution pattern of the vehicle from the speed value of the actual yaw rate, the speed difference from the target yaw rate, or the speed change rate includes:

acquiring a yaw moment of the vehicle;

5. The method of claim 4, wherein calculating a target torque for at least one drive axle or at least one drive wheel of the vehicle during the understeer condition or the oversteer condition, respectively, based on the torque distribution pattern comprises:

if the torque distribution mode is the inter-wheel active torque distribution feedforward adjustment mode, determining a second threshold value of a yaw rate change rate difference value according to an actual attachment coefficient of the road, an actual speed of the vehicle, a current steering wheel angle, a current rear axle side deviation angle and a vehicle emergency factor, and judging whether the inter-wheel active torque distribution feedforward adjustment mode meets a second preset activation condition by utilizing the second threshold value so as to determine the target torque of at least one driving wheel when the inter-wheel active torque distribution feedforward adjustment mode meets the second preset activation condition;

And if the torque distribution mode is the inter-wheel torque distribution feedback adjustment mode, determining a third threshold value of a yaw rate change difference value according to an actual attachment coefficient of the road, an actual speed of the vehicle, the current steering wheel rotation angle, the current rear axle side deflection angle and the vehicle emergency factor, and judging whether the inter-wheel torque distribution feedback adjustment mode meets a third preset activation condition by utilizing the third threshold value so as to determine the target torque of at least one driving wheel when the inter-wheel torque distribution feedback adjustment mode meets the third preset activation condition.

6. The method of claim 5, wherein the determining the target torque of the at least one drive shaft or at least one drive wheel comprises:

7. The method of claim 6, wherein the emergency factor is derived from at least one of a yaw moment, an actual vehicle speed and driving pattern of the vehicle, and a road surface adhesion coefficient of a road on which the vehicle is currently located.

8. A distributed torque distribution device for a vehicle, comprising:

9. A vehicle, characterized by comprising: a memory, a processor and a computer program stored on the memory and executable on the processor, the processor executing the program to implement the distributed torque distribution method of a vehicle as claimed in any one of claims 1 to 7.

10. A computer readable storage medium having stored thereon a computer program, characterized in that the program is executed by a processor for implementing a distributed torque distribution method of a vehicle according to any of claims 1-7.