CN115675635A

CN115675635A - Control method and system for front wheel and rear wheel, electronic device, storage medium and vehicle

Info

Publication number: CN115675635A
Application number: CN202211436861.5A
Authority: CN
Inventors: 刘福星; 宋丹丹
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 a front wheel actual yaw angle; 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 first rear wheel yaw angle based on a vehicle centroid slip angle using the front wheel desired yaw angle; determining a second rear wheel yaw angle based on the desired front wheel yaw angle and a vehicle yaw rate; carrying out weighted calculation on the first rear wheel deflection angle and the second rear wheel deflection angle to obtain a rear 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 method for controlling front and rear wheels, 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 first rear wheel yaw angle based on a vehicle centroid slip angle using the front wheel desired yaw angle;

determining a second rear wheel yaw angle based on the desired front wheel yaw angle and a vehicle yaw rate;

carrying out weighted calculation on the first rear wheel deflection angle and the second rear wheel deflection angle to obtain a rear 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 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;

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 first rear wheel yaw angle acquisition module configured to determine a first rear wheel yaw angle based on a vehicle centroid slip angle using the front wheel desired yaw angle;

a second rear wheel yaw angle acquisition module configured to determine a second rear wheel yaw angle based on the desired front wheel yaw angle and a vehicle yaw angular velocity;

the rear wheel deflection angle acquisition module is configured to perform weighted calculation on the first rear wheel deflection angle and the second rear wheel deflection angle to obtain a rear wheel deflection angle;

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

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 control method, system, electronic device, storage medium, and vehicle for front and rear wheels provided by the present disclosure process an actual deflection angle of a front wheel to obtain a desired deflection angle of the front wheel, and control the front wheel of the vehicle according to the desired deflection angle of the front wheel; the first rear wheel deflection angle and the second rear wheel deflection angle are weighted to obtain the rear wheel deflection angle, the accuracy of the rear wheel deflection angle can be improved, the rear wheel deflection angle can be accurately controlled, the rear wheel of the vehicle can be controlled according to the rear wheel deflection direction and the rear wheel deflection angle, and the stability of the vehicle during steering is further improved. Under the condition that the front wheels are 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 by the scheme, so that the rear wheels are controlled more stably when the vehicle is steered, and the driving safety is improved.

Drawings

In order to more clearly illustrate the technical solutions in the present disclosure or related technologies, the drawings needed to be used in the description of the embodiments or related technologies are briefly introduced below, and it is obvious that the drawings in the following description are only embodiments of the present disclosure, and for those skilled in the art, other drawings can be obtained according to these drawings 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 flowchart of an embodiment according to another application scenario of the present disclosure;

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

For the purpose of promoting a better understanding of the objects, aspects and advantages of the present disclosure, reference is made to the following detailed description taken in conjunction with 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, there is a problem that, during running of a vehicle, particularly during running on a curve, wheels slip due to factors such as an excessively high vehicle speed and a change in tire adhesion, and the vehicle is under-steered or over-steered.

Based on the above description, as shown in fig. 1, the control method for the front and rear wheels according to 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, the vehicle information includes: vehicle self information and vehicle operation information. Wherein the vehicle own information includes: vehicle mass or vehicle tire information; the vehicle operation information includes at least one of: vehicle steering information, vehicle operation information, and 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 vehicle information is acquired in multiple modes, the speed and the accuracy of acquiring the vehicle information are improved, the vehicle is controlled according to the acquired vehicle information, and the efficiency and the accuracy of controlling the vehicle are improved.

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

In specific implementation, the acquired vehicle information comprises 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 processing 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 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 wheels is a yaw angle required for the front wheels when the front wheels are 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 front wheel steering angle control coefficient. 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.

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.

In specific implementation, the vehicle information comprises 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.

When the vehicle is in a driving state, calculating the slip ratio of the vehicle tire, wherein the slip ratio of the vehicle tire comprises the following steps: front wheel slip rate and rear wheel slip rate. And determining the deflection direction of the rear wheel according to the slip ratio of the vehicle tire.

The slip ratio of the vehicle tire is calculated by the following process: acquiring a wheel speed of a vehicle tire, a rolling radius of the vehicle tire and a longitudinal speed of the 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.

The process of determining the rear wheel deflection direction according to the slip ratio of the vehicle tire comprises the following steps: when the vehicle is in a driving state, the slip rate of at least one front wheel meets the first slip rate condition of the front wheel, and the slip rate of at least one rear wheel meets the first slip rate condition of the rear wheel, the vehicle is in an understeer state, and the deflection direction of the rear wheel of the vehicle is in a reverse deflection with the front wheel. For example, when at least one of the front wheel slip ratios is calculated to be less than or equal to-10% and then at least one of the rear wheel slip ratios is calculated to be less than or equal to-10%, the rear wheel deflection direction of the vehicle is the reverse deflection of the front wheel. And when the slip rate of at least one front wheel meets the second slip rate condition of the front wheel and the slip rate of at least one rear wheel meets the second slip rate condition of the rear wheel, the vehicle is in an oversteer state, and the deflection direction of the rear wheel of the vehicle is in the same direction as that of the front wheel. For example, when 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%, the rear wheel deflection direction of the vehicle is the same as the front wheel deflection.

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

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 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.

The process of determining the rear wheel deflection direction according to the slip ratio of the vehicle tire is as follows: when the vehicle is in a braking state, at least one front wheel slip rate meets a first slip rate condition of the front wheels, and at least one rear wheel slip rate meets a first slip rate condition of the rear wheels, 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. For example, when 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 deflection direction of the vehicle is the reverse deflection of the front wheel. And 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 oversteer state, and the deflection direction of the rear wheel of the vehicle is in the same direction as that of the front wheel. For example, at least one of the rear wheel slip ratios is 10% or more and the front wheel slip ratio is 10% or more, and the rear wheel deflection direction of the vehicle is the same as the front wheel deflection direction.

In the scheme, the vehicle state is determined according to the vehicle gear and the acceleration information, so that the determined vehicle state is more accurate. And respectively judging the deflection direction of the rear wheel of the vehicle according to the vehicle state through the slip rate or the slip rate of the vehicle tire. The judgment of the deflection direction of the rear wheel of the vehicle is more in line with the actual requirement of vehicle control.

And 104, determining a first rear wheel deflection angle based on the vehicle mass center side deflection angle by utilizing the expected front wheel deflection angle.

When the steering vehicle is used for steering driving, due to the influence of the centripetal force, the tire of the vehicle is added with the cornering force, so that the tire cornering angle is generated, the mass center cornering angle of the whole vehicle 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. The vehicle operation information comprises the longitudinal vehicle speed, the lateral vehicle speed, the vehicle yaw velocity, the vehicle mass center slip angle and the like of the vehicle, and a vehicle mass center slip angle function is obtained based on a vehicle two-degree-of-freedom model algorithm according to the vehicle operation information. The vehicle mass center sideslip angle function at least comprises the following parameter information: the vehicle mass center slip angle, the vehicle mass center slip angle speed, the vehicle lateral speed and the vehicle acceleration.

In the scheme, the vehicle mass center side slip angle function is obtained through calculation, the first rear wheel deflection angle is obtained through calculation according to the function, the vehicle is controlled, the side slip trend of the tire is weakened, and the driving smoothness is improved.

Step 105, determining a second rear wheel yaw angle based on the desired front wheel yaw angle and the vehicle yaw rate.

In the concrete implementation, when the vehicle is in steering driving, the tire of the vehicle is added with lateral deviation force due to the influence of the centripetal force, so that the tire lateral deviation angle is generated, the yaw rate of the whole vehicle is further influenced, the smaller the yaw rate is, the smaller the tendency of the tire to sideslip is, and the better the steering stability is. The vehicle operation information comprises the longitudinal vehicle speed, the lateral vehicle speed, the vehicle yaw rate, the vehicle mass center and the lateral deviation angle and the like of the vehicle, and the vehicle yaw rate function is obtained based on a vehicle two-degree-of-freedom model algorithm according to the vehicle operation information. Wherein, the vehicle yaw rate function at least comprises the following parameter information: the rate of change of the yaw rate of the vehicle, the acceleration of the vehicle, and the yaw angle of the rear wheels.

In the scheme, a vehicle yaw velocity function is obtained through calculation, and a second rear wheel deflection angle is obtained through calculation according to the function, so that the vehicle is controlled, the sideslip trend of tires is weakened, and the driving smoothness is improved.

And 106, carrying out weighted calculation on the first rear wheel deflection angle and the second rear wheel deflection angle to obtain a rear wheel deflection angle.

In specific implementation, corresponding weights are respectively obtained according to the importance degrees of the first rear wheel deflection angle and the second rear wheel deflection angle to the control of the rear wheel deflection angle, and the rear wheel deflection angle is obtained through calculation according to the first rear wheel deflection angle, the second rear wheel deflection angle and the corresponding weights.

In the scheme, the rear wheel deflection angle can be calculated according to the weight and the importance degree of the first rear wheel deflection angle and the second rear wheel deflection angle, so that the obtained rear wheel deflection angle is more accurate.

And 107, 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 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; the first rear wheel deflection angle and the second rear wheel deflection angle are weighted to obtain the rear wheel deflection angle, the accuracy of the rear wheel deflection angle can be improved, the rear wheel deflection angle can be accurately controlled, the rear wheel of the vehicle can be controlled according to the rear wheel deflection direction and the rear wheel deflection angle, and the stability of the vehicle during steering is further improved. Under the condition that the front wheels are 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 which is controlled only by the rear wheels 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 front wheel average slip ratio 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 front wheel deflection angle to obtain a desired front wheel deflection angle:

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.

In specific implementation, when the vehicle is in a driving 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.

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 performing 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

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.

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 wheels is a yaw angle required for the front wheels when the front wheels are 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 front wheel steering angle control coefficient. 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.

In some embodiments, step 104 comprises:

104A, processing the expected deflection angle of the front wheel based on a rear wheel deflection relation function determined by the vehicle mass center side deflection angle to obtain a first rear wheel deflection angle; and the rear wheel steering angle relation function is obtained according to a vehicle two-degree-of-freedom model algorithm.

During specific implementation, a rear wheel steering angle relation function is obtained according to a vehicle two-degree-of-freedom model algorithm, and a front wheel expected deflection angle 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 plurality of parameter information, and the vehicle mass center slip angle is one of the plurality of parameter information.

And 1042, determining that the plurality of pieces of parameter information meet preset conditions, and obtaining a rear wheel steering angle relation function according to the vehicle mass center side slip angle function and the expected front wheel steering angle.

When the steering vehicle is used for steering driving, due to the influence of the centripetal force, the tire of the vehicle is added with the cornering force, so that the tire cornering angle is generated, the mass center cornering angle of the whole vehicle 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. Wherein the vehicle centroid slip angle is one of the plurality of parameter information. And according to the obtained vehicle mass center side slip angle function, when the parameter information meets a preset condition, obtaining a rear wheel steering angle relation function.

In the scheme, the vehicle mass center side slip angle function is obtained through calculation, and the rear wheel deflection angle is obtained through calculation according to the function, so that the control of the vehicle is realized, the side slip trend of the tire is weakened, and the driving smoothness is improved. And calculating to obtain a rear wheel steering angle relation function through a vehicle mass center side slip angle function, and calculating to obtain a rear wheel deflection angle based on the rear wheel steering angle relation formula function in the execution process of the subsequent steps, wherein 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 a 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 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,

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, the vehicle operation information comprises a vehicle longitudinal speed, a lateral speed, a vehicle yaw rate, a vehicle mass center slip angle and the like, and a vehicle mass center slip angle function is obtained based on a vehicle two-degree-of-freedom model algorithm according to the vehicle operation information.

In the scheme, the vehicle mass center side slip angle function is obtained through calculation, and the rear wheel slip angle is obtained through calculation according to the function, so that the control of the vehicle is realized, the side slip trend of the tire is weakened, and the driving smoothness is improved.

In some embodiments, step 1042 includes:

step 1042A, the step of the parameter information meeting the preset condition includes: the centroid slip angle is zero, the vehicle acceleration is zero, and the rear wheel steering angle relation function is determined according to the vehicle centroid slip angle function:

wherein, delta ₂ | _β＝0 Is the first rear wheel yaw angle.

In specific implementation, the centroid slip angle beta is zero, and the vehicle acceleration is

Substituting the zero into the vehicle mass center side deflection angle function, obtaining a vehicle corner relation function through operation processing, and determining the relation between the vehicle rear wheel deflection angle and the front wheel deflection angle according to the vehicle corner relation function to obtain a first rear wheel deflection angle of the vehicle.

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 first rear wheel deflection angle of the vehicle is ensured, and the running smoothness of the vehicle is ensured.

In some embodiments, step 1042 includes:

step 1042B, the step of the parameter information meeting the preset condition includes: the mass center slip angle is zero, the vehicle yaw angle speed change rate is zero, the vehicle acceleration is zero, and the rear wheel steering angle relation function is determined according to the vehicle mass center slip angle function:

wherein, delta ₂ | _β＝0 Is the first rear wheel yaw angle.

In specific implementation, the mass center slip angle beta is zero, and the change rate of the vehicle yaw angle speed is

Zero, vehicle acceleration

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 first 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.

In some embodiments, step 105 comprises:

step 1051, determining a vehicle yaw rate function based on the vehicle centroid slip angle function, where the centroid slip angle is a ratio of the lateral velocity to the longitudinal velocity, the vehicle yaw rate change rate is zero, the vehicle acceleration is zero, and the rear wheel yaw angle is zero:

step 1052, obtaining an ideal yaw rate by processing the vehicle yaw rate function:

wherein, K is a stable factor,

for ideal yaw rate, L is the front-rear wheelbase of the vehicle, L = a + b.

And 1053, processing the deflection angle of the rear wheel of the vehicle according to the ideal yaw velocity to obtain a second deflection angle of the rear wheel.

In specific implementation, the change rate of the yaw angle speed of the vehicle is changed

Zero, vehicle acceleration

Zero, rear wheel deflection angle delta ₂ And substituting the zero into the vehicle mass center sideslip angle function to obtain a vehicle yaw velocity function. And performing operation processing on the yaw velocity function to obtain an ideal yaw velocity of the vehicle, and calculating to obtain a second rear wheel deflection angle according to the yaw velocity of the vehicle.

In the above-described aspect, the calculated ideal yaw rate is the yaw rate operating section in which the stability of the vehicle is maintained. The vehicle rear wheel yaw direction calculated from the ideal yaw rate is the vehicle rear wheel yaw direction when the yaw rate is in the stable operating region, and the stability of the vehicle when turning can be improved.

In some embodiments, step 1053 comprises:

step 1053A, processing the vehicle yaw rate and the desired yaw rate to obtain a second rear wheel yaw angle:

wherein, delta ₂ | ω is the second rear wheel deflection angle, K _ω For the preset yaw-rate control coefficient,

is the desired yaw rate.

In specific practice, ω _r Is the yaw-rate of the vehicle,

a second rear wheel deflection angle is calculated from the vehicle yaw rate and the desired yaw rate for the desired yaw rate.

In the scheme, the yaw velocity function of the vehicle is obtained through calculation, and the deflection angle of the rear wheel is obtained through calculation according to the function, so that the control of the vehicle is realized, the sideslip trend of the tire is weakened, and the driving smoothness is improved.

In some embodiments, step 106 comprises:

step 1061, weighting the first rear wheel deflection angle and the second rear wheel deflection angle to obtain a rear wheel deflection angle:

wherein, delta _{2 Total} For rear wheel deflection angle, delta ₂ | _β＝0 Is the first rear wheel yaw angle, δ ₂ | ω is the second rear wheel deflection angle, ξ ₁ Is the weight of the deflection angle of the first rear wheel, ξ ₂ Is the weight of the second rear wheel yaw angle.

During specific implementation, corresponding weights are respectively taken for the first rear wheel deflection angle and the second rear wheel deflection angle, and weighting operation is carried out according to the corresponding weights to obtain the rear wheel deflection angle. The weight may reflect a degree of influence of the first rear wheel yaw angle and the second rear wheel yaw angle on the rear wheel yaw angle calculation. Wherein the sum of the weight of the first rear wheel yaw angle and the weight of the second rear wheel yaw angle is 1.

In the scheme, the first rear wheel deflection angle and the second rear wheel deflection angle are subjected to weighted calculation to obtain the rear wheel deflection angle, so that the vehicle mass center side deflection angle and the vehicle yaw velocity are controlled in a stable working interval, and the obtained rear wheel deflection angle is more accurate.

During the running process of the vehicle, preferably when the vehicle runs on a curve, the front wheel state comprises an uncontrolled state or a non-uncontrolled 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 106 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. By means of the scheme, the rear wheel deflection direction is judged in the subsequent steps based on the acquired vehicle information, and the judgment accuracy is improved.

And step 202, judging vehicle gear information.

During specific implementation, vehicle gear information 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 the slip rate 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 wheels by the formula:

S＝(ω·R-u)/(ω·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.

And step 205, 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 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 rate obtained through calculation, the control over the rear wheel of the vehicle is achieved 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 in a direction 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-10%, and then the slip ratio of the front wheel of at least one vehicle is calculated to be less than or equal to-10%, the vehicle is determined to be in an oversteered state, and the deflection direction of the rear wheel is determined to be 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 rate 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 determining that the vehicle is in an oversteer state according to the slip ratio 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 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.

Step 207, calculate the desired yaw angle of the front wheel 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.

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 207 specifically includes:

step 2071, obtain a first rear wheel yaw angle based on the ideal centroid slip angle.

In specific implementation, a vehicle mass center slip angle function is calculated based on a vehicle two-degree-of-freedom model algorithm, a calculated rear wheel deflection angle is obtained according to the vehicle front wheel deflection angle and the vehicle mass center slip angle function, and a first rear wheel deflection angle is obtained. According to the scheme, the vehicle mass center side slip angle function is calculated and obtained according to a vehicle two-degree-of-freedom model algorithm, the first vehicle rear wheel deflection angle is calculated and obtained based on the obtained front wheel deflection angle and the calculated vehicle mass center side slip angle function, the calculation result is more accurate, the control of the vehicle rear wheels is achieved together with the rear wheel deflection direction obtained in the step, and the driving safety is improved.

And 2072, obtaining a second rear wheel deflection angle based on the ideal yaw rate.

In specific implementation, a vehicle yaw velocity function is calculated and obtained based on a vehicle two-degree-of-freedom model algorithm. And obtaining a calculated rear wheel deflection angle according to the vehicle front wheel deflection angle and the vehicle yaw velocity function, and obtaining a second rear wheel deflection angle. According to the scheme, the vehicle yaw velocity function is calculated according to the vehicle two-degree-of-freedom model algorithm, the second rear wheel deflection angle is calculated based on the obtained front wheel deflection angle and the calculated vehicle yaw velocity function, and the calculation result is more accurate.

And 2073, controlling the front wheels of the vehicle according to the desired 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, performing weighted calculation on the first rear wheel deflection angle and the second rear wheel deflection angle to obtain a rear wheel deflection angle.

In specific implementation, when the vehicle runs, preferably when the vehicle is steered, 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, and further a yaw rate and a centroid cornering angle of the whole vehicle are influenced. According to the scheme, two important parameters of the vehicle mass center side slip angle and the vehicle yaw velocity are considered in the calculation process of the rear wheel deflection angle, the vehicle mass center side slip angle and the vehicle yaw velocity are controlled to be in a stable working interval, the control of the rear wheel of the vehicle is achieved together with the rear wheel deflection direction obtained in the previous step, the driving stability is improved, and the safety risk is reduced.

And 209, controlling the rear wheels of the vehicle according to the rear wheel deflection direction and the rear wheel deflection angle.

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.

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:

step 301, 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.

Step 302, vehicle gear information is judged.

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 303, judging the running state of the vehicle according to the longitudinal acceleration information 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, 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 rotary 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 ratio of the vehicle wheel by the following formula:

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 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 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 more 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 oversteer state, the deflection direction of the rear wheel is determined to be deflected 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 deflected in the same direction as that of the front wheel and the deflection angle of the rear wheel, the sliding out of the tail of the vehicle in the tangential direction of the extension 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 same direction with 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 in response to the judgment that the vehicle is in an oversteer state according to the slip rate of the vehicle wheels, determining the deflection direction of the rear wheels to be the same as that of the front wheels, and obtaining a more accurate judgment result.

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

In some embodiments, step 307 specifically comprises:

3071, a first rear wheel yaw angle is obtained based on the ideal centroid slip angle.

Step 3072, a second rear wheel yaw angle is obtained based on the ideal yaw rate.

3073, controlling the front wheel of the vehicle according to the desired deflection angle of the front wheel.

And 308, performing weighted calculation on the first rear wheel deflection angle and the second rear wheel deflection angle to obtain a rear wheel deflection angle.

In specific implementation, when the vehicle runs, preferably when the vehicle is steered, 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, and further a yaw rate and a centroid cornering angle of the whole vehicle are influenced. According to the scheme, two important parameters of the mass center side slip angle and the vehicle yaw velocity of the vehicle are considered in the calculation process of the deflection angle of the rear wheel, the mass center side slip angle and the vehicle yaw velocity of the vehicle are controlled to be in a stable working interval, and the control of the rear wheel of the vehicle is realized together with the deflection direction of the rear wheel obtained in the above step, so that the driving stability is improved, and the safety risk is reduced.

And 309, controlling the rear wheels of the vehicle according to the deflection direction and the deflection angle of the rear wheels.

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 first rear wheel yaw angle acquisition module 404 configured to determine a first rear wheel yaw angle based on a vehicle centroid slip angle using the front wheel desired yaw angle;

a second rear wheel yaw angle acquisition module 405 configured to determine a second rear wheel yaw angle based on the desired front wheel yaw angle and a vehicle yaw rate;

a rear wheel deflection angle obtaining module 406, configured to perform weighted calculation on the first rear wheel deflection angle and the second rear wheel deflection angle to obtain a rear wheel deflection angle;

a vehicle control module 407 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.

the front wheel desired yaw angle acquisition module 402 includes:

a front wheel steering angle control coefficient obtaining unit configured to obtain a front wheel steering angle control coefficient by querying 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 vehicle speed, a front wheel average slip ratio and a front wheel steering angle control coefficient relation table;

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

δ ₁ ＝d*δ

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

the first rear wheel deflection angle acquisition unit is configured to process the expected front wheel deflection angle on the basis of a rear wheel deflection angle relation function determined by a vehicle mass center side deflection angle to obtain a first 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 first rear wheel yaw angle obtaining module 404, the method further includes:

the vehicle body center side slip angle function obtaining unit is configured to obtain a vehicle body center side slip angle function based on a vehicle two-degree-of-freedom model algorithm, the vehicle body center side slip angle function comprises a plurality of pieces of parameter information, and the vehicle body center side slip angle is one of the plurality of pieces of parameter information;

and the rear wheel steering angle relation function acquisition unit is configured to determine that the plurality of pieces of parameter information meet preset conditions, and obtain a rear wheel steering angle relation function according to the vehicle mass center side slip angle function and the expected front wheel deflection angle.

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

the centroid slip angle function acquisition subunit is configured to obtain a vehicle centroid slip angle function based on a 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 Of the rear axleCornering stiffness, δ ₁ Is the deflection angle of the front wheel, u is the longitudinal speed,

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

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

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

a rear wheel steering angle relation function obtaining subunit configured such that the plurality of parameter information satisfying a preset condition includes: the centroid slip angle is zero, the vehicle acceleration is zero, and the rear wheel steering angle relation function is determined according to the vehicle centroid slip angle function:

wherein, delta ₂ | _β＝0 Is the first rear wheel yaw angle.

In some embodiments, the first vehicle turning angle relation function obtaining unit includes:

a rear wheel steering angle relation function obtaining subunit configured such that the plurality of parameter information satisfying a preset condition includes: the centroid slip angle is zero, the vehicle yaw angle speed change rate is zero, the vehicle acceleration is zero, and the rear wheel steering angle relation function is determined according to the vehicle centroid slip angle function:

wherein, delta ₂ | _β＝0 Is the first rear wheel yaw angle.

In some embodiments, the second rear wheel yaw angle acquisition module 405 includes:

a yaw-rate function obtaining unit configured to obtain a magnitude of the centroid yaw angle as a ratio of the lateral velocity to the longitudinal velocity, and determine a vehicle yaw-rate function based on the vehicle centroid yaw-rate function, the vehicle yaw-rate function having a vehicle yaw-rate change rate of zero, the vehicle acceleration of zero, and the rear-wheel yaw angle of zero:

an ideal yaw rate calculation unit configured to obtain an ideal yaw rate by processing the vehicle yaw rate function:

wherein, K is a stable factor,

an ideal yaw rate, L being the fore-aft wheelbase of the vehicle, L = a + b;

and the second rear wheel deflection angle acquisition unit is configured to process the rear wheel deflection angle of the vehicle according to the ideal yaw velocity to obtain a second rear wheel deflection angle.

In some embodiments, the second rear wheel yaw angle acquisition unit includes:

a second rear wheel yaw angle calculation subunit configured to perform arithmetic processing on the vehicle yaw rate and the desired yaw rate to obtain a second rear wheel yaw angle:

is the desired yaw rate.

In some embodiments, the rear wheel control module 406 includes:

a rear wheel deflection angle calculation unit configured to weight the first rear wheel deflection angle and the second rear wheel deflection angle to obtain a rear wheel deflection angle:

wherein, delta _{2 Total} To the rear wheel deflection angle, δ ₂ | _β＝0 Is the first rear wheel steering angle, δ ₂ | ω is the second rear wheel deflection angle, ξ ₁ Weight of deflection angle of the first rear wheel, ξ ₂ Is the weight of the second rear wheel yaw angle.

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

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 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. The input devices may include a keyboard, a mouse, a touch screen, a microphone, various sensors, etc., and the output devices may include a display, a speaker, a vibrator, an 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 device and other devices. 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 of the above embodiments, the present application further provides a vehicle including the control system of the front and rear wheels, or the electronic device, or the storage medium in the above embodiments, where the vehicle device implements the method of controlling the front and rear wheels according to any of the above embodiments.

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 within 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:

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:

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 vehicle speed, a front wheel average slip ratio and a front wheel steering angle control coefficient relation table;

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 said determining a first rear wheel yaw angle based on a vehicle centroid slip angle using said front wheel desired yaw angle comprises:

processing the expected deflection angle of the front wheel based on a rear wheel steering angle relation function determined by a vehicle mass center side deflection angle to obtain a first rear wheel deflection angle; and obtaining the rear wheel steering angle relation function according to a vehicle two-degree-of-freedom model algorithm.

4. The method of claim 1, further comprising, prior to processing the desired front wheel yaw angle to a first rear wheel yaw angle based on a rear wheel yaw relationship function determined from a vehicle centroid slip angle:

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 plurality of parameter information, and the vehicle mass center slip angle is one of the parameter information;

and determining that the parameter information meets a preset condition, and obtaining a rear wheel steering angle relation function according to the vehicle mass center side deflection angle function and the expected front wheel deflection angle.

5. The method of claim 4, wherein the vehicle two-degree-of-freedom model-based algorithm obtains a vehicle centroid slip angle function, comprising:

based on a vehicle two-degree-of-freedom model algorithm, a vehicle mass center side slip angle function is obtained:

6. The method of claim 5, wherein the determining that the parameter information satisfies a predetermined condition, and obtaining a rear wheel steering angle relation function according to the vehicle centroid side slip angle function and the front wheel desired slip angle comprises:

the plurality of parameter information satisfying the preset condition includes: the centroid slip angle is zero, the vehicle acceleration is zero, and the rear wheel steering angle relation function is determined according to the vehicle centroid slip angle function:

wherein, delta ₂ | _β＝0 Is the first rear wheel yaw angle.

7. The method of claim 5, wherein the determining that the parameter information satisfies a predetermined condition, and obtaining a rear wheel steering angle relation function according to the vehicle centroid side slip angle function and the front wheel desired slip angle comprises:

the plurality of parameter information satisfying the preset condition includes: the mass center slip angle is zero, the vehicle yaw angle speed change rate is zero, the vehicle acceleration is zero, and the rear wheel steering angle relation function is determined according to the vehicle mass center slip angle function:

wherein, delta ₂ | _β＝0 Is the first rear wheel yaw angle.

8. The method of claim 5, wherein determining a second rear wheel yaw angle based on the desired front wheel yaw angle and a vehicle yaw rate comprises:

the mass center slip angle is the ratio of the lateral speed to the longitudinal speed, the change rate of the vehicle yaw angular velocity is zero, the vehicle acceleration is zero and the rear wheel deflection angle is zero, and based on the vehicle mass center slip angle function, the vehicle yaw angular velocity function is determined:

and processing the vehicle yaw velocity function to obtain an ideal yaw velocity:

wherein, K is a stable factor,

the ideal yaw angular velocity, L is the front-rear wheelbase of the vehicle, and L = a + b;

and processing the deflection angle of the rear wheel of the vehicle according to the ideal yaw velocity to obtain a second rear wheel deflection angle.

9. The method of claim 8, wherein processing the vehicle rear wheel yaw angle according to the desired yaw rate to obtain a second rear wheel yaw angle comprises:

processing the vehicle yaw rate and the desired yaw rate to obtain a second rear wheel yaw angle:

is the desired yaw rate.

10. The method of claim 1, wherein weighting the first rear wheel steering angle and the second rear wheel steering angle to obtain a rear wheel steering angle comprises:

weighting the first rear wheel deflection angle and the second rear wheel deflection angle for processing to obtain a rear wheel deflection angle:

wherein，δ ₂ Total rear wheel deflection angle, delta ₂ | _β＝0 Is the first rear wheel steering angle, δ ₂ | is the second rear wheel deflection angle, ξ ₁ Is the weight of the deflection angle of the first rear wheel, ξ ₂ Is the weight of the second rear wheel yaw angle.

11. 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;

12. 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 10 when the program is executed by the processor.

13. 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 10.

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