CN115675634A

CN115675634A - Control method and system for front wheel and rear wheel, electronic device, storage medium and vehicle

Info

Publication number: CN115675634A
Application number: CN202211436470.3A
Authority: CN
Inventors: 刘福星; 刘应花
Original assignee: Great Wall Motor Co Ltd
Current assignee: Great Wall Motor Co Ltd
Priority date: 2022-11-16
Filing date: 2022-11-16
Publication date: 2023-02-03

Abstract

The disclosure provides a control method and system for front and rear wheels, an electronic device, a storage medium and a vehicle. The method comprises the following steps: acquiring vehicle information; wherein the vehicle information includes an actual yaw angle of a front wheel; processing the actual deflection angle of the front wheel to obtain an expected deflection angle of the front wheel; judging the deflection direction of the rear wheel of the vehicle according to the vehicle information to obtain the deflection direction of the rear wheel; determining a rear wheel deflection angle based on the yaw rate change rate, the vehicle center of mass yaw angle and the vehicle lateral acceleration using the desired front wheel deflection angle; and controlling the front wheels of the vehicle according to the expected deflection angle of the front wheels, and controlling the rear wheels of the vehicle according to the deflection direction of the rear wheels and the deflection angle of the rear wheels.

Description

Control method and system for front wheel and rear wheel, electronic device, storage medium and vehicle

Technical Field

The present disclosure relates to the field of vehicle control technologies, and in particular, to a method and a system for controlling front and rear wheels, an electronic device, a storage medium, and a vehicle.

Background

In the running process of a vehicle, particularly in the running process of a curve, due to factors such as overhigh speed or tire adhesion force change, wheels slip, the problem of insufficient or over-steering of the vehicle is easy to occur, the vehicle is out of control, and safety accidents are caused.

In view of this, how to avoid the problem of understeer or oversteer of the vehicle and improve driving stability and safety becomes an important research problem.

Disclosure of Invention

In view of the above, an object of the present disclosure is to provide a method, a system, an electronic device, a storage medium and a vehicle for controlling front and rear wheels, so as to solve the problem of understeer or oversteer when the vehicle is running in the prior art.

In view of the above object, a first aspect of the present disclosure provides a front and rear wheel control method, including:

acquiring vehicle information; wherein the vehicle information includes an actual yaw angle of a front wheel;

processing the actual deflection angle of the front wheel to obtain an expected deflection angle of the front wheel;

judging the deflection direction of the rear wheel of the vehicle according to the vehicle information to obtain the deflection direction of the rear wheel;

determining a rear wheel deflection angle based on the yaw rate change rate, the vehicle center of mass yaw angle and the vehicle lateral acceleration using the desired front wheel deflection angle;

and controlling the front wheels of the vehicle according to the expected deflection angle of the front wheels, and controlling the rear wheels of the vehicle according to the deflection direction of the rear wheels and the deflection angle of the rear wheels.

Based on the same inventive concept, a second aspect of the present disclosure provides a control system for front and rear wheels, comprising:

a vehicle information acquisition module configured to acquire vehicle information; wherein the vehicle information includes an actual yaw angle of a front wheel;

the front wheel control module is configured to process the actual deflection angle of the front wheel to obtain an expected deflection angle of the front wheel;

the rear wheel deflection direction acquisition module is configured to judge the deflection direction of the rear wheel of the vehicle according to the vehicle information to obtain the deflection direction of the rear wheel;

a rear wheel deflection angle acquisition module configured to determine a rear wheel deflection angle based on a yaw rate change rate, a vehicle center of mass yaw angle, and a vehicle lateral acceleration using the front wheel desired deflection angle;

and the vehicle control module is configured to control the front wheels of the vehicle according to the expected turning angle of the front wheels and control the rear wheels of the vehicle according to the deflection direction and the deflection angle of the rear wheels.

Based on the same inventive concept, a third aspect of the present disclosure proposes an electronic device comprising a memory, a processor and a computer program stored on the memory and executable by the processor, the processor implementing the method as described above when executing the computer program.

Based on the same inventive concept, a fourth aspect of the present disclosure proposes a non-transitory computer-readable storage medium storing computer instructions for causing a computer to perform the method as described above.

Based on the same inventive concept, a fifth aspect of the present disclosure proposes a vehicle including the control system for front and rear wheels of the second aspect or the electronic device of the third aspect or the storage medium of the fourth aspect.

As can be seen from the foregoing, the method, the system, the electronic device, the storage medium, and the vehicle for controlling front and rear wheels provided by the present disclosure process an actual deflection angle of a front wheel to obtain an expected deflection angle of the front wheel, and control the front wheel of the vehicle according to the expected deflection angle of the front wheel, which is more accurate than directly controlling the front wheel of the vehicle through a steering wheel in the related art. Determining a rear wheel yaw angle based on the yaw rate change rate, the vehicle center of mass yaw angle, and the vehicle lateral acceleration using the desired front wheel yaw angle. When the yaw rate change rate, the mass center slip angle and the vehicle lateral acceleration all meet the preset conditions, the rear wheel deflection angle is determined, the obtained rear wheel deflection angle is more accurate, and the rear wheel can be adjusted and controlled more accurately. Under the condition that the vehicle is under-steered or over-steered, the deflection angles of the front wheels and the rear wheels are controlled and adjusted together when the vehicle is steered, so that the vehicle is more stable than the vehicle only controlled by the rear wheels when the vehicle is steered, and the driving safety is improved.

Drawings

In order to clearly illustrate the technical solutions of the present disclosure or related technologies, the drawings used in the embodiments or related technologies description will be briefly introduced below, and obviously, the drawings in the following description are only embodiments of the present disclosure, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a flow chart of a method of controlling front and rear wheels according to an embodiment of the present disclosure;

FIG. 2 is a first partial flowchart of an embodiment according to another application scenario of the present disclosure;

FIG. 3 is a second partial flowchart of an embodiment of the present disclosure in another application scenario;

FIG. 4 is a schematic structural diagram of a control system for front and rear wheels in accordance with an embodiment of the present disclosure;

fig. 5 is a schematic structural diagram of an electronic device according to an embodiment of the disclosure.

Detailed Description

To make the objects, technical solutions and advantages of the present disclosure more apparent, the present disclosure will be described in further detail below with reference to specific embodiments and the accompanying drawings.

It is to be noted that technical terms or scientific terms used in the embodiments of the present disclosure should have a general meaning as understood by one having ordinary skill in the art to which the present disclosure belongs, unless otherwise defined. The use of "first," "second," and similar terms in the embodiments of the disclosure is not intended to indicate any order, quantity, or importance, but rather to distinguish one element from another. The word "comprising" or "comprises", and the like, means that the element or item preceding the word comprises the element or item listed after the word and its equivalent, but does not exclude other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", and the like are used only to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.

As described above, during the running of the vehicle, particularly when running on a curve, there is a problem that the vehicle is under-steered or oversteered due to the slipping of the wheels caused by the excessively high vehicle speed or the variation of the tire adhesion.

Based on the above description, as shown in fig. 1, the control method for front and rear wheels proposed by the present embodiment includes:

step 101, obtaining vehicle information; wherein the vehicle information includes an actual yaw angle of the front wheel.

In specific implementation, vehicle information is acquired, wherein the vehicle information comprises vehicle basic information and vehicle running information, and the vehicle basic information comprises at least one of the following information: vehicle mass or vehicle tire information, the vehicle operation information including at least one of: vehicle corner information, vehicle running speed or vehicle gear information. There are various ways to obtain vehicle information, for example, corresponding vehicle operation information may be collected by corresponding sensors.

According to the scheme, the deflection direction of the rear wheel is judged based on the acquired vehicle information, so that the judgment accuracy is improved, meanwhile, the deflection angle of the rear wheel is obtained based on the deflection direction of the rear wheel and subsequent calculation, the adjustment of the deflection of the vehicle is completed by adjusting the rear wheel of the vehicle, and the stability of the vehicle in the driving process is improved.

And 102, processing the actual deflection angle of the front wheel to obtain the expected deflection angle of the front wheel, and controlling the front wheel of the vehicle according to the expected deflection angle of the front wheel.

In specific implementation, the acquired vehicle information includes an actual deflection angle of the front wheel, a front wheel steering angle control coefficient is acquired, and the expected deflection angle of the front wheel is obtained by performing operation processing on the actual deflection angle of the front wheel and the front wheel steering angle control coefficient. The actual deflection angle of the front wheel is the deflection angle of the current front wheel of the vehicle, which is obtained through a steering wheel; the front wheel steering angle control coefficient is a coefficient reflecting the relation between the actual steering angle of the front wheel and the expected steering angle of the front wheel, can be obtained by looking up a table, and is related to the vehicle speed and the average slip ratio of the front wheel of the vehicle or the average slip ratio of the front wheel; the desired yaw angle of the front wheel is a yaw angle required for the front wheel when the front wheel is controlled in order to ensure the stability of the vehicle when the vehicle is steered.

In the scheme, the expected deflection angle of the front wheel is obtained by calculating according to the actual deflection angle of the front wheel and the control coefficient of the front wheel steering angle. And then the expected deflection angle of the front wheel obtained according to the calculation is controlled to the front wheel of the vehicle, and compared with the prior art that the front wheel of the vehicle is directly controlled through a steering wheel, the control method is more accurate.

And 103, judging the deflection direction of the rear wheel of the vehicle according to the vehicle information to obtain the deflection direction of the rear wheel.

During specific implementation, judging the deflection direction of the rear wheels according to the vehicle information to obtain a rear deflection direction, judging to obtain a vehicle state according to the vehicle information, and determining the reverse deflection of the rear wheels and the front wheels of the vehicle in response to the fact that the vehicle is in an understeer state; in response to the vehicle being in an oversteer condition, the rear wheels of the vehicle are determined to be co-steered with the front wheels.

In the scheme, the deflection angle of the rear wheel is obtained based on the deflection direction of the rear wheel and subsequent calculation, so that the deflection of the vehicle can be adjusted by adjusting the rear wheel of the vehicle, and the stability of the vehicle in the driving process is improved.

And 104, determining a rear wheel deflection angle based on the yaw rate change rate, the vehicle mass center side deflection angle and the vehicle lateral acceleration by using the expected deflection angle of the front wheels.

In specific implementation, based on the expected deflection angle of the front wheel of the vehicle obtained through calculation, a vehicle mass center side deflection angle function is obtained through calculation based on a vehicle two-degree-of-freedom model algorithm. And obtaining the deflection angle of the rear wheel of the vehicle according to the expected deflection angle of the front wheel of the vehicle and the vehicle mass center side deflection angle function. And according to the obtained vehicle mass center side deflection angle function, when responding to the parameter information and meeting a preset condition, obtaining the deflection angle of the rear wheel. Wherein the preset conditions are that the yaw angular velocity change rate is zero, the vehicle mass center slip angle is zero, and the vehicle lateral acceleration is zero.

In the scheme, the vehicle mass center side slip angle function is calculated according to a vehicle two-degree-of-freedom model algorithm, the vehicle rear wheel deflection angle is calculated based on the calculated expected front wheel deflection angle and the calculated vehicle mass center side slip angle function, the calculation result is more accurate, the vehicle deflection is adjusted together with the rear wheel deflection direction determined in the step, and the driving safety is improved. When the yaw angular velocity change rate and the centroid slip angle both meet preset conditions, the rear wheel deflection angle is obtained, the rear wheel deflection angle obtained through calculation is more accurate, and then the rear wheel is accurately regulated. Through adjusting and controlling the rear wheels, the driving smoothness is improved, and the safety risk in driving is reduced.

And 105, controlling the front wheels of the vehicle according to the expected deflection angle of the front wheels, and controlling the rear wheels of the vehicle according to the deflection direction of the rear wheels and the deflection angle of the rear wheels.

In specific implementation, the expected deflection angle of the front wheel is sent to a controller to control the front wheel, and the deflection direction of the rear wheel and the deflection angle of the rear wheel are sent to the controller to control the rear wheel.

In the above scheme, the front wheels of the vehicle are controlled according to the expected deflection angle of the front wheels, and the rear wheels of the vehicle are controlled according to the deflection direction of the rear wheels and the deflection angle of the rear wheels, so that the cooperative control of the front wheels and the rear wheels of the vehicle is realized.

In the above embodiment, the actual deflection angle of the front wheel is processed to obtain the expected deflection angle of the front wheel, and the front wheel of the vehicle is controlled according to the expected deflection angle of the front wheel, which is more accurate than the control of the front wheel of the vehicle directly through a steering wheel in the related art. Determining a rear wheel yaw angle based on the yaw rate change rate, the vehicle center of mass yaw angle, and the vehicle lateral acceleration using the desired front wheel yaw angle. When the yaw rate change rate, the mass center slip angle and the vehicle lateral acceleration all meet the preset conditions, the rear wheel deflection angle is determined, the obtained rear wheel deflection angle is more accurate, and the rear wheel can be adjusted and controlled more accurately. Under the condition that the vehicle is under-steered or over-steered, the deflection angles of the front wheel and the rear wheel are controlled and adjusted together when the vehicle is steered by the scheme, so that the rear wheel is controlled more stably when the vehicle is steered, and the driving safety is improved.

In some embodiments, the vehicle information includes: vehicle speed, front wheel average slip ratio, and front wheel average slip ratio;

step 102 comprises:

step 1021, obtaining a front wheel steering angle control coefficient by inquiring a vehicle speed, a front wheel average slip ratio and a front wheel steering angle control coefficient relation table; or the front wheel steering angle control coefficient is obtained by inquiring a relation table of the vehicle speed, the average slip ratio of the front wheels and the front wheel steering angle control coefficient.

Step 1022, performing operation processing according to the front wheel steering angle control coefficient and the actual deflection angle of the front wheel to obtain an expected deflection angle of the front wheel:

δ ₁ ＝d*δ

wherein, delta ₁ The desired yaw angle for the front wheels, d the front wheel steering angle control coefficient, and δ the actual yaw angle for the front wheels.

In specific implementation, when the vehicle is in a driving state, the acquired vehicle information includes the average slip rate of the front wheels, and the front wheel steering angle control coefficient can be determined according to the vehicle speed and the average slip rate of the front wheels by inquiring the relation table of the vehicle speed, the average slip rate of the front wheels and the front wheel steering angle control coefficient. For example, when the vehicle speed is zero and the front wheel slip ratio is-0.2%, the front wheel steering angle control coefficient is 0.8.

When the vehicle is in a braking state, the acquired vehicle information comprises the average slip rate of the front wheels, and the front wheel steering angle control coefficient can be determined according to the vehicle speed and the average slip rate of the front wheels by inquiring the relation table of the vehicle speed, the average slip rate of the front wheels and the front wheel steering angle control coefficient. For example, when the vehicle speed is zero and the front wheel slip ratio is 0.2%, the front wheel steering angle control coefficient is 0.8.

And carrying out operation processing according to the front wheel steering angle control coefficient and the actual deflection angle of the front wheel to obtain the expected deflection angle of the front wheel:

δ ₁ ＝d*δ

The actual deflection angle of the front wheel is the deflection angle of the current front wheel of the vehicle obtained through a steering wheel; the front wheel steering angle control coefficient is a coefficient reflecting the relation between the actual deflection angle of the front wheel and the expected deflection angle of the front wheel, can be obtained by table lookup and is related to the vehicle speed and the average slip ratio of the front wheel of the vehicle or the average slip ratio of the front wheel; the desired yaw angle of the front wheel is a yaw angle required for the front wheel when the front wheel is controlled in order to ensure the stability of the vehicle when the vehicle is steered.

In the scheme, the expected deflection angle of the front wheel is obtained by calculating according to the actual deflection angle of the front wheel and the control coefficient of the front wheel steering angle. And then control the vehicle front wheel according to the expected deflection angle of the front wheel that obtains of calculation, it is more accurate than directly controlling the vehicle front wheel through the steering wheel among the correlation technique.

In some embodiments, step 102 comprises:

and 102A, acquiring the actual deflection angle of the front wheel of the turntable.

And step 102B, obtaining vehicle state information, and determining a front wheel compensation deflection angle according to the vehicle state information.

And 102C, processing the actual deflection angle of the front wheel and the compensation deflection angle of the front wheel to obtain the expected deflection angle of the front wheel.

During specific implementation, the actual deflection angle of the front wheel is obtained through a vehicle steering wheel, and vehicle state information is analyzed and processed to determine the front wheel compensation deflection angle. And calculating the actual deflection angle of the front wheel and the compensation deflection angle of the front wheel to obtain the expected deflection angle of the front wheel. Wherein, the expected deflection angle of the front wheel is the deflection angle of the front wheel used for controlling and adjusting the vehicle.

In the above scheme, the expected deflection angle of the front wheel of the vehicle is determined by combining the actual deflection angle of the front wheel obtained by the steering wheel and the compensation deflection angle of the front wheel determined according to the vehicle state information, so that the front wheel can be accurately controlled and adjusted, and the control of the front wheel of the vehicle is more accurate than that of the front wheel of the vehicle directly controlled by the steering wheel in the related technology.

In some embodiments, step 104 comprises:

104A, processing the expected deflection angle of the front wheel based on a rear wheel steering angle relation function determined by the yaw angle speed change rate, the vehicle mass center side deflection angle and the vehicle lateral acceleration to obtain a rear wheel deflection angle; and obtaining the rear wheel steering angle relation function according to a vehicle two-degree-of-freedom model algorithm.

In specific implementation, a rear wheel steering angle relation function is obtained according to a vehicle two-degree-of-freedom model algorithm, and the expected deflection angle of the front wheel is substituted into the rear wheel steering angle relation function to obtain a first rear wheel deflection angle.

In some embodiments, before step 104, further comprising:

step 1041, obtaining a vehicle mass center slip angle function based on a vehicle two-degree-of-freedom model algorithm, wherein the vehicle mass center slip angle function comprises a yaw angle speed change rate, a vehicle mass center slip angle and a vehicle lateral acceleration.

And 1042, determining that the yaw rate change rate, the vehicle mass center slip angle and the vehicle lateral acceleration meet preset conditions, and obtaining a rear wheel steering angle relation function according to the vehicle mass center slip angle function and the expected front wheel yaw angle.

In specific implementation, when a vehicle is steered and driven, due to the influence of a centripetal force, a tire of the vehicle is added with a cornering force, so that a tire cornering angle is generated, the finished vehicle mass center cornering angle is further influenced, the smaller the mass center cornering angle is, the smaller the tire sideslip trend is, and the better the steering stability is. And obtaining a vehicle mass center side slip angle function based on a vehicle two-degree-of-freedom model algorithm. And according to the obtained vehicle mass center slip angle function, when the change rate of the yaw angular velocity, the vehicle mass center slip angle and the vehicle lateral acceleration meet preset conditions, obtaining a rear wheel steering angle relation function. Wherein the preset conditions are that the yaw rate of change is zero, the vehicle centroid slip angle is zero, and the vehicle lateral acceleration is zero.

In the scheme, the vehicle corner relation function is obtained through calculation of the vehicle mass center side deflection angle function, and in the execution process of the subsequent steps, the rear wheel deflection angle is obtained through calculation based on the vehicle corner relation function, so that the rear wheel deflection angle is more accurate.

In some embodiments, step 1041 comprises:

step 1041A, obtaining a vehicle mass center slip angle function based on the vehicle two-degree-of-freedom model algorithm:

wherein m is the mass of the whole vehicle, a is the distance from the center of mass to the front axle, b is the distance from the center of mass to the rear axle, and k ₁ Yaw stiffness, k, of the front axle ₂ Is the cornering stiffness of the rear axle, u is the longitudinal vehicle speed,

is the vehicle acceleration, beta is the vehicle centroid slip angle, omega _r As the yaw rate of the vehicle,

for the rate of change of yaw rate, delta, of the vehicle ₁ For front wheel deflection angle, delta ₂ For rear wheel deflection angle, I _Z Is the rotational inertia of the whole vehicle.

In specific implementation, a vehicle mass center slip angle function is obtained based on a vehicle two-degree-of-freedom model algorithm.

In the scheme, the vehicle corner relation function is obtained through the calculation of the vehicle mass center side deflection angle function, and the rear wheel deflection angle is obtained through calculation based on the vehicle corner relation function in the execution process of the subsequent steps, so that the rear wheel deflection angle is more accurate.

In some embodiments, step 1042 includes:

step 1042A, determining that the centroid slip angle is zero, the vehicle lateral acceleration is zero and the yaw rate change rate is zero, and obtaining a rear wheel deflection angle according to the vehicle centroid slip angle function and the expected front wheel deflection angle:

in specific implementation, the mass center slip angle beta is zero, and the lateral acceleration of the vehicle is

Zero, yaw rate of change

And substituting the zero into the vehicle mass center slip angle function to obtain the vehicle rear wheel deflection angle.

In the scheme, when the centroid slip angle beta is zero, the centroid slip angle can be controlled in a stable working interval, so that the rear wheel deflection angle of the vehicle is ensured, and the running smoothness of the vehicle is ensured. On the basis that the centroid slip angle beta is zero, the vehicle yaw angle speed change rate

And the stability of the vehicle during steering can be further improved.

In some embodiments, step 103 comprises:

and step 1031, judging the vehicle state according to the vehicle information, and determining the vehicle state.

In specific implementation, the vehicle information includes vehicle gear information and acceleration information, and the vehicle state is judged according to the gear information and the acceleration information to determine that the vehicle is in a driving state or a braking state.

The method comprises the steps of obtaining vehicle acceleration information and gear information through a vehicle internal sensor, and judging a vehicle state according to the vehicle acceleration information and the gear information, wherein the vehicle state refers to the state of a vehicle under different accelerations and different gears and comprises one of the following steps: a forward drive state, a forward braking state, a reverse braking state, or a reverse drive state.

The direction of the vehicle acceleration pointing to the vehicle head is a positive value, and the direction pointing to the vehicle tail is a negative value. In response to the fact that the gear information is a forward gear and the acceleration information is a positive value, determining that the vehicle state is a forward driving state; in response to the fact that the gear information is a forward gear and the acceleration information is a negative value, determining that the vehicle state is a forward braking state; in response to the fact that the gear information is a reverse gear and the acceleration information is a positive value, determining that the vehicle state is a reverse braking state; and determining that the vehicle state is a reverse driving state in response to the fact that the gear information is a reverse gear and the acceleration information is a negative value.

Step 1032, in response to determining that the vehicle state is a driving state, calculating a slip ratio of a vehicle tire, and determining a rear wheel deflection direction according to the slip ratio of the vehicle tire, wherein the slip ratio of the vehicle tire comprises: front wheel slip rate and rear wheel slip rate.

In specific implementation, the slip ratio of the vehicle tire is calculated by the following process: acquiring the wheel speed of a vehicle tire, the rolling radius of the vehicle tire and the longitudinal speed of a vehicle; and performing calculation processing on the wheel speed of the vehicle tire, the rolling radius of the vehicle tire and the longitudinal speed of the vehicle to obtain the slip ratio of the vehicle tire, wherein S = (omega. R-u)/(omega. R). Where S is the slip ratio of the vehicle tire, ω is the wheel speed of the vehicle tire, R is the rolling radius of the vehicle tire, and u is the longitudinal speed of the vehicle.

Step 1033, in response to determining that the vehicle state is a braking state, calculating a slip ratio of a vehicle tire, and determining a rear wheel deflection direction according to the slip ratio of the vehicle tire, wherein the slip ratio of the vehicle tire comprises: front wheel slip ratio and rear wheel slip ratio.

In specific implementation, the calculation process of the slip ratio of the vehicle tire is as follows: acquiring a wheel speed of a vehicle tire, a rolling radius of the vehicle tire and a longitudinal speed of the vehicle; and performing operation processing on the wheel speed of the vehicle tire, the rolling radius of the vehicle tire and the longitudinal speed of the vehicle to obtain the slip ratio of the vehicle tire, wherein K = (u-omega.R)/u. Where K is the slip ratio of the vehicle tire, ω is the wheel speed of the vehicle tire, R is the rolling radius of the vehicle tire, and u is the longitudinal speed of the vehicle.

In the scheme, the slip rate or the slip rate of the vehicle wheel is calculated and is used for subsequently judging the deflection direction of the rear wheel, so that the judgment is more accurate.

In some embodiments of the present invention, the,

step 1032 includes:

and step 1032A, responding to the fact that the vehicle is determined to be in a driving state, when at least one front wheel slip rate meets a first front wheel slip rate condition, and at least one rear wheel slip rate meets a first rear wheel slip rate condition, the vehicle is in an understeer state, and the deflection direction of the rear wheels of the vehicle is in reverse deflection with the front wheels.

And step 1032B, in response to the fact that the vehicle is determined to be in the driving state, when the at least one front wheel slip rate meets a front wheel second slip rate condition, and the at least one rear wheel slip rate meets a rear wheel second slip rate condition, the vehicle is in an oversteering state, and the deflection direction of the rear wheels of the vehicle is deflected in the same direction as the front wheels.

When the method is specifically implemented, the first slip ratio condition of the front wheels is that at least one front wheel slip ratio is calculated to be less than or equal to-10 percent, and then at least one rear wheel slip ratio is calculated to be less than or equal to-10 percent; the second slip ratio condition of the front wheels is that at least one rear wheel slip ratio is calculated to be less than or equal to-10%, and then at least one front wheel slip ratio is calculated to be less than or equal to-10%. For example, when the vehicle is in a driving state, at least one front wheel slip ratio is calculated to be less than or equal to-10%, and then at least one rear wheel slip ratio is calculated to be less than or equal to-10%, the rear wheel deflection direction of the vehicle is deflected in the opposite direction of the front wheel. And firstly, calculating that the slip ratio of at least one rear wheel is less than or equal to-10%, and then calculating that the slip ratio of at least one front wheel is less than or equal to-10%, wherein the deflection direction of the rear wheel of the vehicle is the same as that of the front wheel.

Step 1033 includes:

and 1033A, in response to determining that the vehicle is in the braking state, when the at least one front wheel slip rate meets the first front wheel slip rate condition and the at least one rear wheel slip rate meets the first rear wheel slip rate condition, the vehicle is in an understeer state, and the deflection direction of the rear wheels of the vehicle is in a direction opposite to that of the front wheels.

And 1033B, in response to determining that the vehicle is in the braking state, when the at least one front wheel slip rate meets the second front wheel slip rate condition and the at least one rear wheel slip rate meets the second rear wheel slip rate condition, the vehicle is in an oversteer state, and the deflection direction of the rear wheels of the vehicle is in the same direction as that of the front wheels.

In specific implementation, the first slip ratio condition of the rear wheel is that at least one front wheel slip ratio is greater than or equal to 10%, and the rear wheel slip ratio is equal to 10%; the second slip ratio condition of the rear wheels is that at least one rear wheel slip ratio is greater than or equal to 10%, and the front wheel slip ratio is equal to 10%. For example, when the vehicle is in a braking state, at least one of the front wheel slip ratios is 10% or more, and the rear wheel slip ratio is 10% or more, the rear wheel yaw direction of the vehicle is a reverse yaw to the front wheel. At least one rear wheel slip rate is greater than or equal to 10%, the front wheel slip rate is equal to 10%, and the deflection direction of the rear wheel of the vehicle is the same as that of the front wheel.

In the above-described aspect, the slip ratio or slip ratio of the vehicle tire is calculated based on the vehicle state, respectively, and the vehicle rear wheel yaw direction is determined according to a condition that the slip ratio or slip ratio satisfies. And controlling the rear wheel of the vehicle to realize the same-direction deflection or reverse deflection with the front wheel according to the determined deflection direction of the rear wheel of the vehicle. When the deflection direction of the rear wheel of the vehicle is opposite to that of the front wheel, the head of the vehicle can be prevented from sliding out along the tangential direction of the arc line; when the deflection direction of the rear wheel of the vehicle is in the same direction as that of the front wheel, the rear wheel of the vehicle can be prevented from sliding out in the tangential direction of the extension arc line, and the potential safety hazard is reduced.

In the above embodiment, the actual deflection angle of the front wheel is processed to obtain the desired deflection angle of the front wheel, and the front wheel of the vehicle is controlled according to the desired deflection angle of the front wheel, which is more accurate than the control of the front wheel of the vehicle directly through the steering wheel in the related art. Determining a rear wheel yaw angle based on the yaw rate change rate, the vehicle center of mass yaw angle, and the vehicle lateral acceleration using the desired front wheel yaw angle. When the yaw rate change rate, the mass center slip angle and the vehicle lateral acceleration all meet the preset conditions, the rear wheel deflection angle is determined, the obtained rear wheel deflection angle is more accurate, and the rear wheel can be adjusted and controlled more accurately. Under the condition that the vehicle is under-steered or over-steered, the deflection angles of the front wheels and the rear wheels are controlled and adjusted together when the vehicle is steered, so that the vehicle is more stable than the vehicle only controlled by the rear wheels when the vehicle is steered, and the driving safety is improved.

During the running process of the vehicle, preferably when the vehicle runs on a curve, the front wheel state comprises an out-of-control state or a non-out-of-control state.

And when the stress of the tire does not break through the friction circle, determining that the front wheel of the vehicle is in a non-runaway state, executing the steps of the embodiment, and adjusting the deflection of the vehicle by adjusting the front wheel and the rear wheel of the vehicle.

Acquiring the stress information of the vehicle tire, determining that the front wheel of the vehicle is in an out-of-control state when the tire is stressed to break through a friction circle, executing the processes of the step 103 to the step 104 in the embodiment, and adjusting the deflection of the vehicle by adjusting the deflection direction of the rear wheel of the vehicle and the deflection angle of the rear wheel.

It should be noted that the embodiments of the present disclosure can be further described in the following ways:

based on the same inventive concept, in response to the vehicle being in a driving state, another embodiment of the present disclosure in an application scenario is shown in fig. 2, and includes:

in step 201, vehicle information is acquired.

In specific implementation, vehicle information is monitored and obtained through an Electronic Control Unit (ECU), and the vehicle information includes vehicle basic information, vehicle running information, vehicle front wheel steering angle information and the like, wherein the vehicle basic information includes vehicle mass, vehicle tire information and the like, the vehicle running information includes vehicle steering angle information, vehicle running speed, vehicle gear information and the like, and the vehicle front wheel steering angle information is obtained through a steering wheel. According to the scheme, the subsequent steps are used for judging the deflection direction of the rear wheel based on the acquired vehicle information, so that the judgment accuracy is improved.

And step 202, judging vehicle gear information.

During specific implementation, the gear information of the vehicle is acquired through a vehicle internal sensor, wherein the gear information comprises a forward gear (D gear) and a reverse gear (R gear), and a basis is made for subsequent judgment of the deflection direction of the rear wheel of the vehicle.

And step 203, judging the running state of the vehicle according to the longitudinal acceleration information of the vehicle.

In specific implementation, a vehicle speed sensor is arranged in the vehicle, the longitudinal vehicle speed of the vehicle is acquired through the vehicle speed sensor, the longitudinal acceleration of the vehicle is calculated according to the acquired longitudinal vehicle speed of the vehicle, and the running state of the vehicle is judged according to the longitudinal acceleration information of the vehicle, wherein the running state of the vehicle comprises a driving state and a braking state. According to the scheme, the running state of the vehicle is judged according to the longitudinal acceleration information of the vehicle, and in the subsequent step, the slip rate of the vehicle wheels is calculated in response to the fact that the running state of the vehicle is a driving state; and responding to the fact that the vehicle running state is a braking state, calculating the slip rate of the vehicle wheels for subsequent judgment of the deflection direction of the rear wheels of the vehicle.

And step 204, calculating the slip rate of the vehicle wheels.

In specific implementation, vehicle information is acquired through a sensor, and the vehicle information comprises wheel speed, rolling radius of a tire, longitudinal vehicle speed, gear information, vehicle acceleration information and the like. The vehicle comprises a wheel speed sensor and a vehicle speed sensor, the wheel speed sensor is used for collecting the wheel speed of the vehicle, the vehicle speed sensor is used for collecting the longitudinal vehicle speed of the vehicle, a tire rolling radius map is obtained according to a drum experiment, and the tire rolling radius is determined according to the tire pressure and the vehicle speed information of the vehicle. And calculating the slip rate or slip ratio of the vehicle wheels according to the vehicle information, and judging the deflection direction of the rear wheel according to the calculated slip ratio. The slip rate of the vehicle wheels is calculated by the following function:

S＝(ω·R-u)/(ω·R)

where S is the slip of the vehicle tire, ω is the wheel speed of the vehicle tire, R is the rolling radius of the vehicle tire, and u is the longitudinal speed of the vehicle.

And step 205, judging the deflection direction of the rear wheel according to the slip ratio of the vehicle wheel.

In specific implementation, the vehicle state is judged according to the slip ratio of the vehicle wheels obtained through calculation, wherein the vehicle state refers to the running state of the vehicle in the current state and comprises an understeer state and an oversteer state. According to the scheme, the deflection direction of the rear wheel is judged through the slip ratio obtained through calculation, the control of the rear wheel of the vehicle is realized together with the deflection angle of the rear wheel obtained in the following step, the judgment result is more accurate, and the driving safety is improved.

In some embodiments, step 205 specifically includes:

step 2051, in response to calculating the slip ratio of the front wheel of at least one vehicle to be less than or equal to-10%, and then calculating the slip ratio of the rear wheel of at least one vehicle to be less than or equal to-10%, determining that the vehicle is in an understeer state and the deflection direction of the rear wheel is opposite to that of the front wheel.

In specific implementation, by judging that the slip ratio of the vehicle wheels is satisfied, the slip ratio of at least one front wheel of the vehicle is calculated to be less than or equal to minus 10%, then the slip ratio of at least one rear wheel of the vehicle is calculated to be less than or equal to minus 10%, the vehicle is determined to be in an understeer state, the deflection direction of the rear wheel is determined to be the reverse deflection with the front wheel, so that the deflection angle of the rear wheel is obtained through calculation in the subsequent step process, the rear wheel is controlled to be adjusted according to the deflection direction of the reverse deflection with the front wheel and the deflection angle of the rear wheel, the slipping-out of the head of the vehicle along the tangential direction of an arc line is avoided, and potential safety hazards are reduced.

And step 2052, in response to that the slip ratio of the rear wheel of at least one vehicle is calculated to be less than or equal to minus 10 percent, and then the slip ratio of the front wheel of at least one vehicle is calculated to be less than or equal to minus 10 percent, determining that the vehicle is in an oversteer state, and the deflection direction of the rear wheel is the same as that of the front wheel.

During specific implementation, by judging that the slip rates of the vehicle wheels meet, the slip rate of at least one rear wheel of the vehicle is calculated to be less than or equal to-10%, then the slip rate of at least one front wheel of the vehicle is calculated to be less than or equal to-10%, the vehicle is determined to be in an oversteered state, the deflection direction of the rear wheel is determined to be deflected in the same direction as the front wheel, so that the deflection angle of the rear wheel is calculated in the subsequent step process, the rear wheel is controlled to be adjusted according to the deflection direction deflected in the same direction as the front wheel and the deflection angle of the rear wheel, the tangential direction sliding of a rear extension arc line of the vehicle is avoided, and potential safety hazards are reduced.

And step 2053, determining the deflection direction of the rear wheel according to the slip ratio of the vehicle wheel.

In specific implementation, the deflection direction of the rear wheel of the vehicle is judged through the slip ratio of the vehicle wheel obtained through calculation, wherein the deflection direction comprises the deflection in the direction opposite to the front wheel and the deflection in the same direction as the front wheel. Determining the deflection direction of the rear wheels to be the reverse deflection of the front wheels in response to judging that the vehicle is in an understeer state according to the slip rate of the vehicle wheels; and in response to the fact that the vehicle is judged to be in an oversteer state according to the slip rate of the vehicle wheels, the deflection direction of the rear wheels is determined to be the same as the deflection direction of the front wheels, and the judgment result is more accurate.

And step 206, acquiring the actual deflection angle of the front wheel.

In specific implementation, the actual deflection angle of the front wheel of the vehicle is obtained through a steering wheel of the vehicle.

In step 207, a desired yaw angle of the front wheel is calculated based on the actual yaw angle of the front wheel.

In specific implementation, the calculation processing is carried out according to the front wheel steering angle control coefficient and the actual deflection angle of the front wheel to obtain the expected deflection angle of the front wheel:

δ ₁ ＝d*δ

And obtaining the front wheel steering angle control coefficient by inquiring a relation table of the vehicle speed, the average slip ratio of the front wheels and the front wheel steering angle control coefficient.

When the vehicle is in a driving state, the acquired vehicle information comprises the average slip rate of the front wheels, and the control coefficient of the front wheel steering angle can be determined according to the vehicle speed and the average slip rate of the front wheels by inquiring the relation table of the vehicle speed, the average slip rate of the front wheels and the control coefficient of the front wheel steering angle. For example, when the vehicle speed is zero and the front wheel slip ratio is-0.2%, the front wheel steering angle control coefficient is 0.8.

In some embodiments, step 207 specifically includes:

step 2071, calculate a rear wheel yaw angle based on the desired yaw angle of the front wheel.

In specific implementation, vehicle operation information is obtained, and operation processing is performed on the vehicle operation information based on a vehicle two-degree-of-freedom model algorithm to obtain a vehicle mass center slip angle function.

The vehicle running information comprises longitudinal vehicle speed u and vehicle acceleration

Mass center slip angle beta of vehicle and yaw angular velocity omega of vehicle _r And rate of change of yaw rate of vehicle

(ii) a Substituting the vehicle running information into the vehicle two-degree-of-freedom model algorithm for operation processing to obtain a vehicle mass center slip angle function:

wherein m is the vehicle mass, a is the distance from the center of mass to the front axle, b is the distance from the center of mass to the rear axle, and k ₁ Yaw stiffness, k, of the front axle ₂ Yaw stiffness of the rear axle, δ ₁ For front wheel deflection angle, delta ₂ For rear wheel deflection angle, I _Z Is the rotational inertia of the whole vehicle.

Setting the mass center slip angle beta to zero and the lateral acceleration of the vehicle

Is zero, yaw angle velocity change rate

Substituting the zero into a vehicle mass center side slip angle function to obtain a vehicle rear wheel deflection angle:

when the centroid slip angle beta is zero, the centroid slip angle can be controlled in a stable working range, so that the rear wheel deflection angle of the vehicle is ensured, and the running smoothness of the vehicle is ensured. On the basis that the centroid side slip angle beta is zero, the vehicle yaw angle speed change rate

And the steering angle is zero, so that the stability of the vehicle during steering can be further improved.

And 2072, controlling the front wheels of the vehicle according to the expected deflection angle of the front wheels.

When the method is specifically implemented, the expected deflection angle of the front wheel is sent to the controller, and the controller controls the front wheel of the vehicle based on the control information, so that the driving smoothness is improved, and the safety risk in driving is reduced.

And 208, controlling the rear wheels of the vehicle according to the rear wheel deflection direction and the rear wheel deflection angle.

When the vehicle is specifically implemented, the deflection direction of the rear wheel and the deflection angle of the rear wheel are sent to the controller, and the controller controls the rear wheel of the vehicle based on control information, wherein the control information comprises the deflection direction of the rear wheel and the deflection angle of the rear wheel, so that the driving smoothness is improved, and the safety risk in driving is reduced.

Based on the same inventive concept, in response to the vehicle being in a braking state, another embodiment of the present disclosure in an application scenario is shown in fig. 3, and includes:

in step 301, vehicle information is acquired.

Step 302, vehicle gear information is judged.

And step 303, judging the running state of the vehicle according to the longitudinal acceleration information of the vehicle.

In specific implementation, the vehicle comprises a vehicle speed sensor, the vehicle speed sensor is used for collecting the longitudinal vehicle speed of the vehicle, the longitudinal acceleration of the vehicle is calculated according to the obtained longitudinal vehicle speed of the vehicle, and the vehicle running state is judged according to the longitudinal acceleration information of the vehicle, wherein the vehicle running state comprises a driving state and a braking state. According to the scheme, the running state of the vehicle is judged according to the longitudinal acceleration information of the vehicle, and in the subsequent step, the slip rate of the vehicle wheels is calculated in response to the fact that the running state of the vehicle is a driving state; and responding to the fact that the vehicle running state is a braking state, calculating the slip rate of the vehicle wheels for subsequent judgment of the deflection direction of the rear wheels of the vehicle.

Step 304, calculating the slip rate of the vehicle wheel.

In specific implementation, vehicle information is acquired through a sensor, and the vehicle information comprises wheel speed, rolling radius of a tire, longitudinal vehicle speed, gear information, vehicle acceleration information and the like. The vehicle comprises a wheel speed sensor and a vehicle speed sensor, the wheel speed sensor is used for collecting the wheel speed of the vehicle, the vehicle speed sensor is used for collecting the longitudinal vehicle speed of the vehicle, a tire rolling radius map is obtained according to a drum experiment, and the tire rolling radius is determined according to the tire pressure and the vehicle speed information of the vehicle. And calculating the slip rate or slip ratio of the vehicle wheels according to the vehicle information, and judging the deflection direction of the rear wheels according to the calculated slip rate. Calculating the slip rate of the vehicle wheel by the function:

K＝(u-ω·R)/u

where K is the slip ratio of the vehicle tire, ω is the wheel speed of the vehicle tire, R is the rolling radius of the vehicle tire, and u is the longitudinal speed of the vehicle.

And 305, judging the deflection direction of the rear wheel according to the slip rate of the vehicle wheel.

In specific implementation, the vehicle state is judged according to the calculated slip rate of the vehicle wheels, wherein the vehicle state refers to the running state of the vehicle in the current state and comprises an understeer state and an oversteer state. According to the scheme, the deflection direction of the rear wheel is judged through the slip rate obtained through calculation, the control on the rear wheel of the vehicle is realized together with the deflection angle of the rear wheel obtained in the following step, the judgment result is more accurate, and the driving safety is improved.

In some embodiments, step 305 specifically includes:

3051, in response to calculating that at least one of a slip ratio of front wheels of the vehicle is greater than or equal to 10% and a slip ratio of rear wheels of the vehicle is equal to 10%, determining that the vehicle is in an understeer state and a yaw direction of the rear wheels is a yaw direction opposite to the front wheels.

During specific implementation, by judging that the slip rates of the vehicle wheels are met, the slip rate of at least one front wheel of the vehicle is more than or equal to 10%, and the slip rate of a rear wheel of the vehicle is equal to 10%, the vehicle is determined to be in an under-steering state, the deflection direction of the rear wheel is determined to be in reverse deflection with the front wheel, so that the deflection angle of the rear wheel is obtained through calculation in the subsequent step process, the rear wheel is controlled to be adjusted according to the deflection direction in reverse deflection with the front wheel and the deflection angle of the rear wheel, the slipping of the head of the vehicle in the tangential direction of a delay arc line is avoided, and potential safety hazards are reduced.

And step 3052, in response to calculating that the slip ratio of at least one rear wheel of the vehicle is greater than or equal to 10% and the slip ratio of a front wheel of the vehicle is equal to 10%, determining that the vehicle is in an oversteer state and the deflection direction of the rear wheel is in the same direction as that of the front wheel.

During specific implementation, by judging that the slip rates of the vehicle wheels are met, the slip rate of at least one rear wheel of the vehicle is larger than or equal to 10%, and the slip rate of a front wheel of the vehicle is equal to 10%, the vehicle is determined to be in an oversteering state, the deflection direction of the rear wheel is determined to be in the same direction as that of the front wheel, so that the deflection angle of the rear wheel is obtained through calculation in the subsequent step process, the rear wheel is controlled to be adjusted according to the deflection direction in the same direction as that of the front wheel and the deflection angle of the rear wheel, the slipping-out of the tail of the vehicle in the tangential direction of a delay arc line is avoided, and potential safety hazards are reduced.

And step 3053, determining the deflection direction of the rear wheel according to the slip ratio of the vehicle wheel.

In specific implementation, the deflection direction of the rear wheel of the vehicle is judged through the slip ratio of the vehicle wheel obtained through calculation, wherein the deflection direction comprises the deflection in the direction opposite to the front wheel and the deflection in the direction same as the front wheel. Determining the deflection direction of the rear wheels to be the reverse deflection of the front wheels in response to judging that the vehicle is in an understeer state according to the slip rate of the wheels of the vehicle; and determining that the vehicle is in an oversteer state according to the slip rate of the vehicle wheels, and determining that the deflection direction of the rear wheels is the same as that of the front wheels, so that the determination result is more accurate.

And step 306, acquiring the actual deflection angle of the front wheel.

In specific implementation, the actual deflection angle of the front wheel of the vehicle is obtained through the steering wheel of the vehicle.

Step 307, calculate the desired yaw angle of the front wheel based on the actual yaw angle of the front wheel.

δ ₁ ＝d*δ

wherein, delta ₁ And d is a front wheel steering angle control coefficient, and delta is a front wheel actual steering angle.

And obtaining the control coefficient of the front wheel steering angle by inquiring a relation table of the vehicle speed, the average slip ratio of the front wheel and the control coefficient of the front wheel steering angle.

When the vehicle is in a braking state, the obtained vehicle information comprises the average slip rate of the front wheels, and the control coefficient of the front wheel steering angle can be determined according to the vehicle speed and the average slip rate of the front wheels by inquiring the relation table of the vehicle speed, the average slip rate of the front wheels and the control coefficient of the front wheel steering angle. For example, when the vehicle speed is zero and the front wheel slip ratio is 0.2%, the front wheel steering angle control coefficient is 0.8.

In some embodiments, step 307 specifically includes:

step 3071, a rear wheel yaw angle is calculated based on the desired yaw angle of the front wheel.

Vehicle mass center slip angle beta and vehicle yaw angular velocity omega _r And rate of change of yaw rate of vehicle

Substituting the vehicle running information into the vehicle two-degree-of-freedom model algorithm for operation processing to obtain a vehicle mass center slip angle function:

wherein m is the mass of the whole vehicle, a is the distance from the center of mass to the front axle, b is the distance from the center of mass to the rear axle, and k ₁ Yaw stiffness, k, of the front axle ₂ Is the cornering stiffness of the rear axle, delta ₁ For front wheel deflection angle, delta ₂ For rear wheel deflection angle, I _Z Is the rotational inertia of the whole vehicle.

Is zero, yaw angle velocity change rate

Substituting the zero into the vehicle mass center sideslip angle function to obtain the vehicle rear wheel deflection angle:

Step 3072, controlling the front wheels of the vehicle according to the expected deflection angle of the front wheels.

When the method is specifically implemented, the deflection direction of the rear wheel and the deflection angle of the rear wheel are sent to a controller, and the controller controls the rear wheel of the vehicle based on control information, wherein the control information comprises the deflection direction of the rear wheel and the deflection angle of the rear wheel, so that the driving smoothness is improved, and the safety risk in driving is reduced.

It should be noted that the method of the embodiments of the present disclosure may be executed by a single device, such as a computer or a server. The method of the embodiment can also be applied to a distributed scene and completed by the mutual cooperation of a plurality of devices. In such a distributed scenario, one of the multiple devices may only perform one or more steps of the method of the embodiments of the present disclosure, and the multiple devices interact with each other to complete the method.

It should be noted that the above describes some embodiments of the disclosure. Other embodiments are within the scope of the following claims. In some cases, the actions or steps recited in the claims may be performed in a different order than in the embodiments described above and still achieve desirable results. In addition, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In some embodiments, multitasking and parallel processing may also be possible or may be advantageous.

Based on the same inventive concept, corresponding to the method of any embodiment, the disclosure also provides a control system for front and rear wheels.

Referring to fig. 4, the control system for the front and rear wheels includes:

a vehicle information acquisition module 401 configured to acquire vehicle information; wherein the vehicle information includes a front wheel actual yaw angle;

a front wheel expected deflection angle obtaining module 402 configured to process the actual deflection angle of the front wheel to obtain a front wheel expected deflection angle;

a rear wheel deflection direction obtaining module 403, configured to determine a rear wheel deflection direction of the vehicle according to the vehicle information, so as to obtain a rear wheel deflection direction;

a rear wheel yaw angle acquisition module 404 configured to determine a rear wheel yaw angle based on a yaw rate change rate, a vehicle center of mass yaw angle, and a vehicle lateral acceleration using the front wheel desired yaw angle;

a vehicle control module 405 configured to control the front wheels of the vehicle according to the desired yaw angle of the front wheels, and to control the rear wheels of the vehicle according to the yaw direction of the rear wheels and the yaw angle of the rear wheels.

In some embodiments, the vehicle information includes: vehicle speed, front wheel average slip ratio and front wheel average slip ratio;

the front wheel desired yaw angle acquisition module 402 includes:

the front wheel steering angle control coefficient acquisition unit is configured to obtain a front wheel steering angle control coefficient by inquiring a vehicle speed, a front wheel average slip ratio and a front wheel steering angle control coefficient relation table; or obtaining a front wheel steering angle control coefficient by inquiring a relation table of vehicle speed, the average slip ratio of the front wheels and the front wheel steering angle control coefficient;

a front wheel desired deflection angle obtaining unit configured to perform arithmetic processing according to the front wheel steering angle control coefficient and the front wheel actual deflection angle to obtain a front wheel desired deflection angle:

δ ₁ ＝d*δ

In some embodiments, the front wheel desired yaw angle acquisition module 402 includes:

a front wheel actual deflection angle acquisition unit configured to acquire a front wheel actual deflection angle of the turntable;

the front wheel compensation deflection angle acquisition unit is configured to acquire vehicle state information and determine a front wheel compensation deflection angle according to the vehicle state information;

a front wheel desired deflection angle calculation unit configured to obtain a front wheel desired deflection angle by processing the front wheel actual deflection angle and the front wheel compensation deflection angle.

In some embodiments, the rear wheel yaw angle acquisition module 404 includes:

a rear wheel deflection angle acquisition unit configured to process the expected front wheel deflection angle based on a rear wheel angular relation function determined by the yaw rate change rate, the vehicle mass center side deflection angle and the vehicle lateral acceleration to obtain a rear wheel deflection angle; and the rear wheel steering angle relation function is obtained according to a vehicle two-degree-of-freedom model algorithm.

In some embodiments, before the rear wheel deflection angle obtaining module 404, the method further includes:

the vehicle mass center yaw angle function acquisition unit is configured to obtain a vehicle mass center yaw angle function based on a vehicle two-degree-of-freedom model algorithm, wherein the vehicle mass center yaw angle function comprises a yaw angle speed change rate, a vehicle mass center yaw angle and a vehicle lateral acceleration;

and the rear wheel steering angle relation function acquisition unit is configured to determine that the yaw velocity change rate, the vehicle mass center slip angle and the vehicle lateral acceleration meet preset conditions, and obtain a rear wheel steering angle relation function according to the vehicle mass center slip angle function and the expected front wheel deflection angle.

In some embodiments, the centroid slip angle function acquisition unit includes:

a centroid slip angle function obtaining subunit configured to obtain a vehicle centroid slip angle function based on the vehicle two-degree-of-freedom model algorithm:

wherein m is the vehicle mass, a is the distance from the center of mass to the front axle, b is the distance from the center of mass to the rear axle, and k ₁ Yaw stiffness, k, of the front axle ₂ The cornering stiffness of the rear axle, u the longitudinal vehicle speed,

is the vehicle acceleration, beta is the vehicle mass center slip angle, omega _r As the yaw rate of the vehicle,

In some embodiments, the rear wheel steering angle relation function obtaining unit includes:

a rear wheel steering angle relation function obtaining subunit configured to determine that the centroid slip angle is zero, the vehicle lateral acceleration is zero, and the yaw angle rate of change is zero, and obtain a rear wheel yaw angle from the vehicle centroid slip angle function and the desired front wheel yaw angle:

in some embodiments, the rear wheel yaw direction acquisition module 303 includes:

a vehicle state judging unit configured to judge a vehicle state according to the vehicle information, and determine the vehicle state;

a slip ratio calculation unit configured to calculate a slip ratio of a vehicle tire in response to determining that the vehicle state is a driving state, and determine a rear wheel yaw direction according to the slip ratio of the vehicle tire, wherein the slip ratio of the vehicle tire includes: the front wheel slip rate and the rear wheel slip rate; alternatively, the first and second electrodes may be,

a slip ratio calculation unit configured to calculate a slip ratio of a vehicle tire in response to determining that the vehicle state is a braking state, and determine a rear wheel yaw direction from the slip ratio of the vehicle tire, wherein the slip ratio of the vehicle tire includes: front wheel slip ratio and rear wheel slip ratio.

In some embodiments of the present invention, the,

the slip ratio calculation unit includes:

a reverse deflection judging subunit, configured to respond to the determination that the vehicle is in the driving state, the at least one front wheel slip rate satisfies the first front wheel slip rate condition, and when the at least one rear wheel slip rate satisfies the first rear wheel slip rate condition, the vehicle is in an understeer state, and the rear wheel deflection direction of the vehicle is in reverse deflection with the front wheels;

the equidirectional deflection judging subunit is configured to respond to the condition that the vehicle is determined to be in a driving state, the at least one front wheel slip rate meets a second front wheel slip rate condition, and when the at least one rear wheel slip rate meets a second rear wheel slip rate condition, the vehicle is in an oversteering state, and the deflection direction of the rear wheels of the vehicle is equidirectional deflection with the front wheels;

the slip ratio calculation unit includes:

a reverse deflection judging subunit, configured to respond to the determination that the vehicle is in a braking state, the vehicle is in an understeer state when the at least one front wheel slip rate satisfies the front wheel first slip rate condition and the at least one rear wheel slip rate satisfies the rear wheel first slip rate condition, and the deflection direction of the rear wheels of the vehicle is in reverse deflection with the front wheels;

and the equidirectional deflection judging subunit is configured to respond to the condition that the vehicle is determined to be in a braking state, the vehicle is in an oversteering state when the at least one front wheel slip rate meets the front wheel second slip rate condition and the at least one rear wheel slip rate meets the rear wheel second slip rate condition, and the deflection direction of the rear wheels of the vehicle is deflected in the same direction with the front wheels.

For convenience of description, the above devices are described as being divided into various modules by functions, and are described separately. Of course, the functionality of the various modules may be implemented in the same one or more software and/or hardware implementations of the present disclosure.

The device of the above embodiment is used for implementing the corresponding control method for the front and rear wheels in any of the foregoing embodiments, and has the beneficial effects of the corresponding method embodiment, which are not described herein again.

Based on the same inventive concept, corresponding to any of the above-mentioned embodiments, the present disclosure further provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor, where the processor executes the program to implement the front and rear wheel control method according to any of the above-mentioned embodiments.

Fig. 5 is a schematic diagram illustrating a more specific hardware structure of an electronic device according to this embodiment, where the device may include: a processor 1010, a memory 1020, an input/output interface 1030, a communication interface 1040, and a bus 1050. Wherein the processor 1010, memory 1020, input/output interface 1030, and communication interface 1040 are communicatively coupled to each other within the device via a bus 1050.

The processor 1010 may be implemented by a general-purpose CPU (Central Processing Unit), a microprocessor, an Application Specific Integrated Circuit (ASIC), or one or more Integrated circuits, and is configured to execute related programs to implement the technical solutions provided in the embodiments of the present disclosure.

The Memory 1020 may be implemented in the form of a ROM (Read Only Memory), a RAM (Random Access Memory), a static storage device, a dynamic storage device, or the like. The memory 1020 may store an operating system and other application programs, and when the technical solution provided by the embodiments of the present specification is implemented by software or firmware, the relevant program codes are stored in the memory 1020 and called to be executed by the processor 1010.

The input/output interface 1030 is used for connecting an input/output module to input and output information. The i/o module may be configured as a component in a device (not shown) or may be external to the device to provide a corresponding function. Wherein the input devices may include a keyboard, mouse, touch screen, microphone, various sensors, etc., and the output devices may include a display, speaker, vibrator, indicator light, etc.

The communication interface 1040 is used for connecting a communication module (not shown in the drawings) to implement communication interaction between the present apparatus and other apparatuses. The communication module may implement communication in a wired manner (e.g., a USB (Universal Serial Bus), a network cable, etc.), or in a Wireless manner (e.g., a mobile network, a WIFI (Wireless Fidelity, wireless network communication technology), a bluetooth, etc.).

The bus 1050 includes a path to transfer information between various components of the device, such as the processor 1010, memory 1020, input/output interface 1030, and communication interface 1040.

It should be noted that although the above-mentioned device only shows the processor 1010, the memory 1020, the input/output interface 1030, the communication interface 1040 and the bus 1050, in a specific implementation, the device may also include other components necessary for normal operation. In addition, those skilled in the art will appreciate that the above-described apparatus may also include only those components necessary to implement the embodiments of the present description, and not necessarily all of the components shown in the figures.

The electronic device of the foregoing embodiment is used for implementing a corresponding method for controlling front and rear wheels in any of the foregoing embodiments, and has the beneficial effects of the corresponding method embodiment, which are not described again here.

Based on the same inventive concept, the present disclosure also provides a non-transitory computer-readable storage medium storing computer instructions for causing a computer to execute the method for controlling front and rear wheels according to any of the above embodiments, corresponding to any of the above-described embodiment methods.

Computer-readable media of the present embodiments, including both non-transitory and non-transitory, removable and non-removable media, may implement information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static Random Access Memory (SRAM), dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), read Only Memory (ROM), electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information that can be accessed by a computing device.

The computer instructions stored in the storage medium of the above embodiment are used to enable the computer to execute the control method for the front and rear wheels according to any of the above embodiments, and have the beneficial effects of corresponding method embodiments, which are not described herein again.

Based on the same inventive concept, corresponding to the method of any embodiment, the present application further provides a vehicle, which includes the control system, or the electronic device, or the storage medium of the front and rear wheels in the embodiment, and the vehicle device implements the method for controlling the front and rear wheels in any embodiment.

The vehicle of the foregoing embodiment is used for implementing the control method for the front and rear wheels according to any of the foregoing embodiments, and has the beneficial effects of the corresponding method embodiments, which are not described herein again.

Those of ordinary skill in the art will understand that: the discussion of any embodiment above is meant to be exemplary only, and is not intended to intimate that the scope of the disclosure, including the claims, is limited to these examples; within the idea of the present disclosure, also technical features in the above embodiments or in different embodiments may be combined, steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present disclosure as described above, which are not provided in detail for the sake of brevity.

In addition, well-known power/ground connections to Integrated Circuit (IC) chips and other components may or may not be shown in the provided figures for simplicity of illustration and discussion, and so as not to obscure the embodiments of the disclosure. Furthermore, devices may be shown in block diagram form in order to avoid obscuring embodiments of the present disclosure, and this also takes into account the fact that specifics with respect to implementation of such block diagram devices are highly dependent upon the platform within which the embodiments of the present disclosure are to be implemented (i.e., specifics should be well within purview of one skilled in the art). Where specific details (e.g., circuits) are set forth in order to describe example embodiments of the disclosure, it should be apparent to one skilled in the art that the embodiments of the disclosure can be practiced without, or with variation of, these specific details. Accordingly, the description is to be regarded as illustrative instead of restrictive.

While the present disclosure has been described in conjunction with specific embodiments thereof, many alternatives, modifications, and variations thereof will be apparent to those skilled in the art in light of the foregoing description. For example, other memory architectures, such as Dynamic RAM (DRAM), may use the discussed embodiments.

The disclosed embodiments are intended to embrace all such alternatives, modifications and variances which fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalents, improvements, and the like that may be made within the spirit and principles of the embodiments of the disclosure are intended to be included within the scope of the disclosure.

Claims

1. A method of controlling front and rear wheels, the method comprising:

acquiring vehicle information; wherein the vehicle information includes a front wheel actual yaw angle;

2. The method of claim 1, wherein the vehicle information comprises: vehicle speed, front wheel average slip ratio, and front wheel average slip ratio;

the processing the actual deflection angle of the front wheel to obtain the expected deflection angle of the front wheel comprises the following steps:

obtaining a front wheel steering angle control coefficient by inquiring a relation table of vehicle speed, front wheel average slip ratio and front wheel steering angle control coefficient; or obtaining a front wheel steering angle control coefficient by inquiring a relation table of vehicle speed, the average slip ratio of the front wheels and the front wheel steering angle control coefficient;

processing according to the front wheel steering angle control coefficient and the actual deflection angle of the front wheel to obtain the expected deflection angle of the front wheel:

δ ₁ ＝d*δ

3. The method of claim 1, wherein processing the actual yaw angle of the front wheel to obtain a desired yaw angle of the front wheel comprises:

acquiring the actual deflection angle of a front wheel of a turntable;

acquiring vehicle state information, and determining a front wheel compensation deflection angle according to the vehicle state information;

and processing the actual deflection angle of the front wheel and the compensation deflection angle of the front wheel to obtain the expected deflection angle of the front wheel.

4. The method of claim 1, wherein determining a rear wheel yaw angle based on a yaw rate change rate, a vehicle center of mass yaw angle, and a vehicle lateral acceleration using the desired yaw angle for the front wheels comprises:

processing the expected deflection angle of the front wheel based on a rear wheel steering angle relation function determined by the yaw angular velocity change rate, the vehicle mass center side deflection angle and the vehicle lateral acceleration to obtain a rear wheel deflection angle; and obtaining the rear wheel steering angle relation function according to a vehicle two-degree-of-freedom model algorithm.

5. The method of claim 1, further comprising, prior to processing the desired yaw angle of the front wheels to a rear wheel yaw angle based on a rear wheel yaw relationship function determined from a yaw rate change rate, a vehicle center of mass yaw angle, and a vehicle lateral acceleration:

obtaining a vehicle mass center sideslip angle function based on a vehicle two-degree-of-freedom model algorithm, wherein the vehicle mass center sideslip angle function comprises a yaw angle speed change rate, a vehicle mass center sideslip angle and a vehicle lateral acceleration;

and determining that the yaw rate change rate, the vehicle mass center slip angle and the vehicle lateral acceleration meet preset conditions, and obtaining a rear wheel steering angle relation function according to the vehicle mass center slip angle function and the expected front wheel slip angle.

6. The method of claim 1, wherein the vehicle two-degree-of-freedom model-based algorithm obtains a vehicle centroid slip angle function, comprising:

based on the vehicle two-degree-of-freedom model algorithm, obtaining a vehicle mass center slip angle function:

wherein m is the vehicle mass, a is the distance from the center of mass to the front axle, b is the distance from the center of mass to the rear axle, and k ₁ Yaw stiffness, k, of the front axle ₂ Is the cornering stiffness of the rear axle, u is the longitudinal vehicle speed,

is the vehicle acceleration, beta is the vehicle centroid slip angle, omega _r Is the yaw-rate of the vehicle,

7. The method of claim 6, wherein the determining that the yaw rate change rate, the vehicle center-of-mass yaw angle, and the vehicle lateral acceleration satisfy a predetermined condition, and deriving a rear-wheel steering angle relationship function from the vehicle center-of-mass yaw angle function and the desired front-wheel yaw angle comprises:

determining that the centroid slip angle is zero, the vehicle lateral acceleration is zero and the yaw angle speed change rate is zero, and obtaining a rear wheel deflection angle according to the vehicle centroid slip angle function and the expected front wheel deflection angle:

8. the method according to claim 1, wherein the determining the vehicle rear wheel deflection direction according to the vehicle information to obtain the rear wheel deflection direction comprises:

judging the vehicle state according to the vehicle information to determine the vehicle state;

in response to determining that the vehicle state is a driving state, calculating a slip ratio of a vehicle tire, and determining a rear wheel deflection direction according to the slip ratio of the vehicle tire, wherein the slip ratio of the vehicle tire comprises: the front wheel slip rate and the rear wheel slip rate; alternatively, the first and second electrodes may be,

in response to determining that the vehicle state is a braking state, calculating a slip ratio of a vehicle tire, and determining a rear wheel deflection direction according to the slip ratio of the vehicle tire, wherein the slip ratio of the vehicle tire comprises: front wheel slip ratio and rear wheel slip ratio.

9. The method of claim 8,

the step of calculating the slip ratio of the vehicle tire in response to the determination that the vehicle state is the driving state, and determining the rear wheel deflection direction according to the slip ratio of the vehicle tire comprises the following steps:

when the at least one front wheel slip rate meets a first front wheel slip rate condition and the at least one rear wheel slip rate meets a first rear wheel slip rate condition in response to determining that the vehicle is in a driving state, the vehicle is in an understeer state and the rear wheel deflection direction of the vehicle is in a reverse deflection direction with the front wheels;

when the at least one front wheel slip rate meets a second front wheel slip rate condition and the at least one rear wheel slip rate meets a second rear wheel slip rate condition in response to determining that the vehicle is in the driving state, the vehicle is in an oversteering state, and the deflection direction of the rear wheels of the vehicle is in the same direction as that of the front wheels;

the step of calculating the slip ratio of the vehicle tire in response to the step of determining that the vehicle state is the braking state, and determining the rear wheel deflection direction according to the slip ratio of the vehicle tire comprises the following steps:

in response to determining that the vehicle is in a braking state, when at least one front wheel slip rate meets a first front wheel slip rate condition and at least one rear wheel slip rate meets a first rear wheel slip rate condition, the vehicle is in an understeer state and a rear wheel deflection direction of the vehicle is in a reverse deflection direction with respect to the front wheels;

and in response to determining that the vehicle is in the braking state, when the at least one front wheel slip ratio meets the second front wheel slip ratio condition and the at least one rear wheel slip ratio meets the second rear wheel slip ratio condition, the vehicle is in an oversteering state, and the deflection direction of the rear wheels of the vehicle is in the same direction as the front wheels.

10. A control system for front and rear wheels, comprising:

a vehicle information acquisition module configured to acquire vehicle information; wherein the vehicle information includes a front wheel actual yaw angle;

the front wheel expected deflection angle acquisition module is configured to process the actual deflection angle of the front wheel to obtain a front wheel expected deflection angle;

and the vehicle control module is configured to control the front wheels of the vehicle according to the expected turning angle of the front wheels and control the rear wheels of the vehicle according to the rear wheel deflection direction and the rear wheel deflection angle.

11. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the method of any one of claims 1 to 9 when the program is executed by the processor.

12. A non-transitory computer-readable storage medium storing computer instructions for causing a computer to perform the method of any one of claims 1 to 9.

13. A vehicle characterized by comprising the control system of front and rear wheels of claim 10 or the electronic device of claim 11 or the storage medium of claim 12.