Vehicle control method, device, equipment and medium

Abstract

The invention provides a vehicle control method and device, equipment and a medium, and the method comprises the steps: obtaining the kinetic parameters of a vehicle under the condition that the vehicle runs on a separated road surface, and the kinetic parameters comprise the actual yaw velocity of the vehicle; according to the kinetic parameters of the vehicle, determining a target rear wheel limiting rotation angle and a target yaw velocity; a target rear wheel rotation angle is determined based on the error between the actual yaw velocity and the target yaw velocity and the target rear wheel limiting rotation angle, and the absolute value of the target rear wheel rotation angle is smaller than the target rear wheel limiting rotation angle; and controlling the rear wheel steering of the vehicle based on the target rear wheel steering angle. The target rear wheel turning angle of the vehicle is determined, the absolute value of the target rear wheel turning angle is smaller than the target rear wheel limiting turning angle, rear wheel turning of the vehicle is controlled through the target rear wheel turning angle, and the stability of the vehicle is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle control, and particularly relates to a vehicle control method, device, equipment and medium. Background Art

[0002] A split road surface (or a two-way road surface) refers to a road surface with different adhesion forces on both sides. When a vehicle is driving on a split road surface, the whole vehicle will deviate towards the low-adhesion side, thus affecting the lateral stability of the vehicle. In the related art, the slip ratio can be controlled through a Traction Control System (TCS for short), so as to improve the traction and handling stability of the vehicle under various driving conditions. However, on a split road surface, only controlling the slip ratio may still cause the vehicle body to be unstable.

[0003] It can be seen that how to further improve the stability of the vehicle on a split road surface is an urgent problem to be solved. Summary of the Invention

[0004] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a vehicle control method, device, equipment and medium for solving the above problems.

[0005] The vehicle control method provided by the present invention includes:

[0006] When the vehicle is driving on a split road surface, obtain the dynamic parameters of the vehicle, where the dynamic parameters include the actual yaw rate of the vehicle;

[0007] According to the dynamic parameters of the vehicle, determine a target rear-wheel limit angle and a target yaw rate;

[0008] Based on the error between the actual yaw rate and the target yaw rate, and the target rear-wheel limit angle, determine a target rear-wheel angle, where the absolute value of the target rear-wheel angle is less than the target rear-wheel limit angle;

[0009] Control the rear-wheel steering of the vehicle based on the target rear-wheel angle.

[0010] In an embodiment of the present invention, the step of determining a target rear-wheel limit angle according to the dynamic parameters of the vehicle includes:

[0011] Based on a first preset condition, a lateral force balance equation and the dynamic parameters of the vehicle, determine a first rear-wheel limit angle, where the first preset condition includes that the lateral acceleration and the center-of-mass sideslip angle of the vehicle are both equal to a first preset value;

[0012] Based on the second preset condition, the lateral moment balance equation, and the dynamic parameters of the vehicle, determine the second rear wheel limit angle, where the second preset condition includes that both the yaw angular acceleration and the sideslip angle of the vehicle are equal to a second preset value;

[0013] Among the multiple rear wheel limit angles, determine the rear wheel limit angle with the smallest absolute value as the target rear wheel limit angle, where the multiple rear wheel limit angles include the first rear wheel limit angle and the second rear wheel limit angle;

[0014] Wherein, both the lateral moment balance equation and the lateral force balance equation are equations determined based on a two-degree-of-freedom vehicle model.

[0015] In an embodiment of the present invention, the method further includes:

[0016] Based on the third preset condition, the lateral force balance equation, the lateral moment balance equation, and the dynamic parameters of the vehicle, determine the third rear wheel limit angle, where the third preset condition includes that the sideslip angle change rate, the sideslip angle, and the yaw angular acceleration of the vehicle are all equal to a third preset value, and the multiple rear wheel limit angles further include the third rear wheel limit angle.

[0017] In an embodiment of the present invention, the method further includes:

[0018] The multiple rear wheel limit angles further include the maximum rear wheel angle of the vehicle.

[0019] In an embodiment of the present invention, the step of determining the target yaw angular velocity according to the dynamic parameters of the vehicle includes:

[0020] Based on the fourth preset condition, the dynamic parameters of the vehicle, and a two-degree-of-freedom vehicle model, determine the target yaw angular velocity, where the fourth preset condition includes that both the yaw angular acceleration and the lateral acceleration of the vehicle are equal to a fourth preset value.

[0021] In an embodiment of the present invention, the method further includes:

[0022] Judge whether the states of the vehicle all meet the target conditions;

[0023] When the states of the vehicle all meet the target conditions, determine that the vehicle is driving on a split road surface; wherein, the target conditions include at least one of the following conditions:

[0024] The TCS of the vehicle has been activated;

[0025] The absolute value of the wheel speed difference between both sides of the vehicle is greater than a first threshold;

[0026] The wheel acceleration of the low - adhesion side wheel of the vehicle is less than a second threshold value;

[0027] The slip ratio of the low - adhesion side wheel of the vehicle is greater than a third threshold value;

[0028] The opening degree of the throttle pedal of the vehicle is greater than a fourth threshold value, and the brake pedal of the vehicle is not depressed;

[0029] The absolute value of the braking pressure difference between both sides of the vehicle is greater than a fifth threshold value.

[0030] In an embodiment of the present invention, the method further includes:

[0031] When the vehicle is traveling on a split road surface, determine the target slip ratio of the target axle and the target slip ratio of the low - adhesion side wheel;

[0032] Based on the target slip ratio of the target axle, determine the target axle speed of the target axle, and based on the target slip ratio of the low - adhesion side wheel, determine the target wheel speed of the low - adhesion side wheel;

[0033] Based on the error between the target axle speed and the actual axle speed of the target axle, determine the driving torque, and drive the target axle according to the driving torque;

[0034] Based on the error between the target wheel speed and the actual wheel speed of the low - adhesion side wheel, determine the braking torque of the low - adhesion side wheel, and brake the low - adhesion side wheel according to the braking torque.

[0035] The vehicle control device provided by the present invention includes:

[0036] A first acquisition module, when the vehicle is traveling on a split road surface, acquires the dynamic parameters of the vehicle, and the dynamic parameters include the actual yaw rate of the vehicle;

[0037] A first determination module, configured to determine a target rear - wheel limit angle and a target yaw rate according to the dynamic parameters of the vehicle;

[0038] A second determination module, configured to determine a target rear - wheel angle based on the error between the actual yaw rate and the target yaw rate, and the target rear - wheel limit angle, and the absolute value of the target rear - wheel angle is less than the target rear - wheel limit angle;

[0039] A first control module, configured to control the rear - wheel steering of the vehicle based on the target rear - wheel angle.

[0040] In an embodiment of the present invention, the first determination module is specifically configured to:

[0041] Based on the first preset condition, the lateral force balance equation, and the dynamic parameters of the vehicle, determine the first rear wheel limit angle, where the first preset condition includes that both the lateral acceleration and the sideslip angle of the vehicle's center of mass are equal to the first preset value;

[0042] Based on the second preset condition, the lateral moment balance equation, and the dynamic parameters of the vehicle, determine the second rear wheel limit angle, where the second preset condition includes that both the yaw angular acceleration and the sideslip angle of the vehicle's center of mass are equal to the second preset value;

[0043] Among the multiple rear wheel limit angles, determine the rear wheel limit angle with the smallest absolute value as the target rear wheel limit angle, where the multiple rear wheel limit angles include the first rear wheel limit angle and the second rear wheel limit angle;

[0044] Wherein, both the lateral moment balance equation and the lateral force balance equation are equations determined based on a two-degree-of-freedom vehicle model.

[0045] In an embodiment of the present invention, the first determination module is specifically further configured to:

[0046] Based on the third preset condition, the lateral force balance equation, the lateral moment balance equation, and the dynamic parameters of the vehicle, determine the third rear wheel limit angle, where the third preset condition includes that the rate of change of the sideslip angle of the vehicle's center of mass, the sideslip angle, and the yaw angular acceleration are all equal to the third preset value, and the multiple rear wheel limit angles further include the third rear wheel limit angle.

[0047] In an embodiment of the present invention, the multiple rear wheel limit angles further include the maximum rear wheel angle of the vehicle.

[0048] In an embodiment of the present invention, the first determination module is specifically further configured to:

[0049] Based on the fourth preset condition, the dynamic parameters of the vehicle, and the two-degree-of-freedom vehicle model, determine the target yaw angular velocity, where the fourth preset condition includes that both the yaw angular acceleration and the lateral acceleration of the vehicle are equal to the fourth preset value.

[0050] In an embodiment of the present invention, the vehicle control device further includes:

[0051] A judgment module, configured to judge whether the states of the vehicle all meet the target conditions;

[0052] A third determination module, configured to determine that the vehicle is driving on a separated road surface when the states of the vehicle all meet the target conditions; wherein, the target conditions include at least one of the following conditions:

[0053] The TCS of the vehicle has been activated;

[0054] The absolute value of the wheel speed difference on both sides of the vehicle is greater than a first threshold value;

[0055] The wheel acceleration of the low-adhesion side wheel of the vehicle is less than a second threshold value;

[0056] The slip ratio of the low-adhesion side wheel of the vehicle is greater than a third threshold value;

[0057] The opening degree of the throttle pedal of the vehicle is greater than a fourth threshold value, and the brake pedal of the vehicle is not depressed;

[0058] The absolute value of the brake pressure difference on both sides of the vehicle is greater than a fifth threshold value.

[0059] In an embodiment of the present invention, the vehicle control device further includes:

[0060] A fourth determination module, configured to determine the target slip ratio of the target axle and the target slip ratio of the low-adhesion side wheel when the vehicle is traveling on a separated road surface;

[0061] A fifth determination module, configured to determine the target axle speed of the target axle based on the target slip ratio of the target axle, and determine the target wheel speed of the low-adhesion side wheel based on the target slip ratio of the low-adhesion side wheel;

[0062] A second control module, configured to determine a driving torque based on the error between the target axle speed and the actual axle speed of the target axle, and drive the target axle according to the driving torque;

[0063] A third control module, configured to determine a braking torque based on the error between the target wheel speed and the actual wheel speed of the low-adhesion side wheel, and brake the low-adhesion side wheel according to the braking torque.

[0064] The electronic device provided by the present invention, the electronic device includes:

[0065] One or more processors;

[0066] A storage device, configured to store one or more programs, when the one or more programs are executed by the one or more processors, enabling the electronic device to implement the vehicle control method.

[0067] The computer-readable storage medium provided by the present invention, on which a computer program is stored, when the computer program is executed by a processor of a computer, enabling the computer to execute the vehicle control method.

[0068] Advantages of this technical solution: When the vehicle is driving on a separated road surface, the target rear wheel angle of the vehicle is determined, and the absolute value of the target rear wheel angle is less than the target rear wheel limit angle; by controlling the rear wheel steering of the vehicle with the above target rear wheel angle, it can help the vehicle better adapt to road surface changes, avoid losing control due to the skidding of one side of the wheels, and can effectively reduce the risk of overshoot of the target rear wheel angle, further improving the vehicle stability.

[0069] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present invention. Brief Description of the Drawings

[0070] The accompanying drawings herein are incorporated into the specification and constitute a part of this specification, showing embodiments consistent with the present invention, and are used together with the specification to explain the principles of the present invention. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings according to these drawings without creative efforts. In the drawings:

[0071] Figure 1 is one of the flowcharts of the vehicle control method shown in an exemplary embodiment of the present invention;

[0072] Figure 2 is a schematic diagram of a two-degree-of-freedom vehicle model shown in an exemplary embodiment of the present invention;

[0073] Figure 3 is the architecture diagram of a vehicle control system shown in an exemplary embodiment of the present invention;

[0074] Figure 4 is the second flowchart of the vehicle control method shown in an exemplary embodiment of the present invention;

[0075] Figure 5 is the flowchart for determining the target slip ratio shown in an exemplary embodiment of the present invention;

[0076] Figure 6 is the block diagram of a vehicle control device shown in an exemplary embodiment of the present invention;

[0077] Figure 7 shows a schematic diagram of the structure of a computer system of an electronic device suitable for implementing the embodiments of the present invention. Detailed Embodiments

[0078] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand the other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention, rather than for limiting the protection scope of the present invention.

[0079] It should be noted that the diagrams provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. Therefore, only the components related to the present invention are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in actual implementation can be arbitrarily changed, and the layout type of its components may also be more complex.

[0080] In the following description, a large number of details are explored to provide a more thorough explanation of the embodiments of the present invention. However, it is obvious to those skilled in the art that the embodiments of the present invention can be implemented without these specific details. In other embodiments, well-known structures and devices are shown in the form of block diagrams rather than in detail to avoid making the embodiments of the present invention difficult to understand.

[0081] Please refer to Figure 1 , Figure 1 which is a flowchart of a vehicle control method shown in an exemplary embodiment of the present invention. As Figure 1 shown, in an exemplary embodiment, the vehicle control method includes steps S110 to S130, which are introduced in detail as follows:

[0082] Step S110, when the vehicle is driving on a separated road surface, obtain the dynamic parameters of the vehicle, where the dynamic parameters include the actual yaw rate of the vehicle.

[0083] Step S120, determine the target rear wheel limit angle and the target yaw rate according to the dynamic parameters of the vehicle.

[0084] Step S130, based on the error between the actual yaw rate and the target yaw rate, and the target rear wheel limit angle, determine the target rear wheel angle, where the absolute value of the target rear wheel angle is less than the target rear wheel limit angle;

[0085] Step S140, control the rear wheel steering of the vehicle based on the target rear wheel angle.

[0086] The above vehicle control method of the present invention can be executed by a vehicle control system.

[0087] The above-mentioned target rear-wheel limit angle is an angle, and the absolute value of the target rear-wheel angle needs to be less than the target rear-wheel limit angle. The target rear-wheel limit angle is greater than 0, without distinguishing the rear-wheel steering direction; the target rear-wheel angle may be greater than 0 or less than 0, which is specifically related to the rear-wheel steering direction. For example, in some application scenarios, when controlling the rear wheels to turn left, the target rear-wheel angle determined by the control system is greater than 0; when controlling the rear wheels to turn right, the target rear-wheel angle determined by the control system is less than 0.

[0088] In the embodiments of the present invention, when the vehicle is driving on a split road surface, by determining the target rear-wheel angle and actively controlling the rear-wheel steering based on the target rear-wheel angle, the driving stability of the vehicle on the split road surface can be improved, and at the same time, the drivability of the whole vehicle on the split road surface can be improved; and the present invention also determines the target rear-wheel angle based on the target rear-wheel limit angle, so that the absolute value of the target rear-wheel angle is less than the target rear-wheel limit angle, which can effectively reduce the risks such as overshoot or oscillation of the target rear-wheel angle, thereby further improving the vehicle stability.

[0089] In some embodiments, the above step 130 includes:

[0090] Perform a first PID (Proportional-Integral-Differential) calculation based on the error between the actual yaw rate and the target yaw rate, and limit the result of the first PID calculation based on the target rear-wheel limit angle to obtain the target rear-wheel angle.

[0091] In the embodiments of the present invention, through the above first PID calculation, the target rear-wheel angle can be effectively calculated, thereby realizing the precise control of vehicle steering; and the present invention simultaneously limits the result of the first PID calculation based on the target rear-wheel limit angle, which is beneficial to avoiding overshoot of the target rear-wheel angle.

[0092] Optionally, in the above step S120, determining the target rear-wheel limit angle according to the dynamic parameters of the vehicle includes:

[0093] Based on a first preset condition, a lateral force balance equation, and the dynamic parameters of the vehicle, determine a first rear-wheel limit angle, where the first preset condition includes that the lateral acceleration and the center-of-mass sideslip angle of the vehicle are both equal to a first preset value;

[0094] Based on a second preset condition, a lateral moment balance equation, and the dynamic parameters of the vehicle, determine a second rear-wheel limit angle, where the second preset condition includes that the yaw angular acceleration and the center-of-mass sideslip angle of the vehicle are both equal to a second preset value;

[0095] Determine the rear-wheel limit angle with the smallest absolute value among multiple rear-wheel limit angles as the target rear-wheel limit angle, where the multiple rear-wheel limit angles include the first rear-wheel limit angle and the second rear-wheel limit angle;

[0096] Among them, the lateral moment balance equation and the lateral force balance equation are both equations determined based on a two-degree-of-freedom vehicle model.

[0097] For the convenience of understanding, the following combines Figure 2 to illustrate the two-degree-of-freedom vehicle model and related balance equations in this embodiment.

[0098] Simplify the vehicle model, and let the relevant motion characteristics of the vehicle satisfy the following eight assumption conditions a to h:

[0099] a. The longitudinal driving speed of the four-wheel steering vehicle is constant.

[0100] b. Assume that the steering system has no effect on the vehicle.

[0101] c. Assume that the suspension system has no effect on the vehicle.

[0102] d. Assume that the vehicle does not perform other motions except for the yaw motion around the z-axis and the lateral motion in the plane. The z-axis is the axis perpendicular to the vehicle bottom surface.

[0103] e. Assume that the air has no resistance effect on the vehicle.

[0104] f. Assume that when the vehicle driving force is small, the lateral force of the ground will not have any effect on the tire side slip characteristics.

[0105] g. A linear characteristic is presented for the side slip of the tire.

[0106] h. Do not consider the change in tire mechanical characteristics caused by the change in the vehicle vertical load direction and the effect of the tire self-aligning moment.

[0107] Based on the above eight assumption conditions, after fully synthesizing the relevant motion forms such as the lateral and yaw of the vehicle, a two-degree-of-freedom vehicle model about the vehicle can be constructed, that is, the "bicycle model". The schematic diagram of the two-degree-of-freedom vehicle model is as Figure 2 shown.

[0108] The dynamic equation of the two-degree-of-freedom model vehicle is as follows

[0109]

[0110]

[0111] In the above formula, m represents the total vehicle mass; u represents the longitudinal vehicle speed; ωr represents the yaw angular velocity; represents the lateral acceleration; Ff represents the lateral force of the front axle; Fr represents the lateral force of the rear axle; σf represents the front wheel steering angle; σr represents the rear wheel steering angle; Iz represents the total vehicle yaw moment of inertia; represents the yaw angular acceleration; a represents the wheelbase of the front axle; b represents the wheelbase of the rear axle.

[0112] The above formula 1 is the force balance equation, and formula 2 is the moment balance equation. Assuming that the tire cornering characteristics are linear, that is:

[0113] Ff = k1 * α1 (3)

[0114] Fr = k2 * α2 (4)

[0115] Among them, k1 represents the cornering stiffness of the front axle; k2 represents the cornering stiffness of the rear axle; α1 represents the cornering angle of the front axle; α2 represents the cornering angle of the rear axle. The definitions of other parameters are as described above.

[0116] According to the geometric relationship, the following formula can be determined:

[0117]

[0118]

[0119] Among them, β represents the sideslip angle of the center of mass, and the definitions of other parameters are as described above.

[0120] Combining the above formulas 1 to 6, after arrangement, the above lateral force balance equation and lateral moment balance equation can be obtained respectively, as follows:

[0121]

[0122] Among them, the above formula 7 is the lateral force balance equation, and formula 8 is the lateral moment balance equation. The definitions of relevant parameters can be referred to the explanations of the above formulas.

[0123] In the embodiment of the present invention, the above first rear wheel limit angle is determined based on the first preset condition, the above lateral force balance equation, and the dynamic parameters of the vehicle. The first preset condition includes that the lateral acceleration of the vehicle and the sideslip angle of the center of mass are both equal to the first preset value, and the first preset value can be 0 or a value close to 0. When the lateral acceleration of the vehicle and the sideslip angle of the center of mass are both equal to 0 or close to 0, the vehicle body is relatively stable.

[0124] In this embodiment, taking the first preset value as 0 as an example, substituting into the above formula 7, the relevant formula for determining the first rear wheel limit angle σrlim1 can be obtained as follows:

[0125]

[0126] Formula 9 is determined based on the above first preset condition and the above lateral force balance equation. Substituting the relevant parameters in the dynamic parameters of the vehicle into formula 9, the above first rear wheel limit angle can be obtained.

[0127] In the embodiment of the present invention, the above-mentioned second rear-wheel limit angle is determined based on a second preset condition, the above-mentioned lateral moment balance equation, and the dynamic parameters of the vehicle. The second preset condition includes that the sideslip angle of the vehicle's center of mass and the yaw angular acceleration are both equal to a second preset value, where the second preset value can also be 0 or a value close to 0. When the sideslip angle of the vehicle's center of mass and the yaw angular acceleration are both equal to 0 or close to 0, the vehicle body is relatively stable.

[0128] In this embodiment, taking the second preset value as 0 as an example, substituting into the above formula 8, the relevant formula for determining the second rear-wheel limit angle σrlim2 can be obtained as follows:

[0129]

[0130] Formula 10 is determined based on the above-mentioned second preset condition and the above-mentioned lateral moment balance equation. Substituting the relevant parameters in the dynamic parameters of the vehicle into Formula 10, the above-mentioned second rear-wheel limit angle can be obtained.

[0131] It should be noted that in each formula in the embodiment of the present invention, the definitions of the same parameters are all consistent. To avoid repetition, the parameters that have been explained will not be described again under each formula.

[0132] In the embodiment of the present invention, the first rear-wheel limit angle and the second rear-wheel limit angle of the vehicle are respectively determined by the above method, and the one with the smallest absolute value among the multiple rear-wheel limit angles (including the above first rear-wheel angle and second rear-wheel angle) is determined as the target rear-wheel limit angle, which is beneficial to improving the accuracy of the target rear-wheel limit angle.

[0133] Optionally, the method further includes:

[0134] Based on a third preset condition, the lateral force balance equation, the lateral moment balance equation, and the dynamic parameters of the vehicle, determine the third rear-wheel limit angle. The third preset condition includes that the rate of change of the sideslip angle of the vehicle's center of mass, the sideslip angle of the center of mass, and the yaw angular acceleration are all equal to a third preset value. The multiple rear-wheel limit angles also include the third rear-wheel limit angle.

[0135] The above-mentioned third preset value can be 0 or a value close to 0. When the rate of change of the sideslip angle of the center of mass, the sideslip angle of the center of mass, and the yaw angular acceleration are all equal to the third preset value, the vehicle body is relatively stable.

[0136] Taking the above-mentioned third preset value as 0 as an example, the determination formula for the third rear-wheel limit angle σrlim3 is as follows:

[0137]

[0138] Equation 11 is determined based on the above lateral force balance equation, lateral moment balance equation, and the third preset condition. Substituting the relevant parameters in the dynamic parameters of the above vehicle into Equation 11, the above third rear wheel limit angle can be obtained. The specific derivation process of Equation 11 is as follows:

[0139] Let in Equation 7 and Equation 8 The following can be obtained respectively:

[0140]

[0141] After organizing Equation 12 and Equation 13, we can get:

[0142]

[0143] From Equation 15 / Equation 14, we can get:

[0144]

[0145] (k1*σf + k2*σr)*a 2 k1 + b 2 k2

[0146] = ((a*k1 - b*k2) - m*u*u)*(a*k1*σf - b*k2*σr)

[0147]

[0148] Dividing both the numerator and denominator of the above Equation 16 by (a + b)*k1*k2, the above Equation 11 can be obtained.

[0149] The present invention combines the lateral force balance equation, the lateral moment balance equation, and the above third preset condition, and further determines the third rear wheel limit angle based on the dynamic parameters of the vehicle, which can improve the comprehensiveness of the above multiple rear wheel limit angles, thereby facilitating the improvement of the accuracy of the target rear wheel limit angle.

[0150] Optionally, the multiple rear wheel limit angles further include the maximum rear wheel angle σrlimcal of the vehicle.

[0151] In the embodiment of the present invention, the determination method of the target rear wheel limit angle σrlim is as follows:

[0152] σrlim = min{abs(σrlim1), abs(σrlim2), abs(σrlim3), abs(σrlimcal)}

[0153] Where abs represents taking the absolute value.

[0154] In the embodiments of the present invention, σrlim1, σrlim2, σrlim3 and σrlimcal are considered simultaneously, and the one with the smallest absolute value is taken as the target cornering limit, which is beneficial to further improving the accuracy of the target cornering limit.

[0155] Optionally, determining the target yaw rate according to the dynamic parameters of the vehicle includes:

[0156] Based on a fourth preset condition, the dynamic parameters of the vehicle, and a two-degree-of-freedom vehicle model, determining the target yaw rate, where the fourth preset condition includes that both the yaw angular acceleration and the lateral acceleration of the vehicle are equal to a fourth preset value.

[0157] The above fourth preset value can be 0 or a value close to 0. When both the yaw angular acceleration and the lateral acceleration of the vehicle are equal to the fourth preset value, the vehicle body is relatively stable. That is, the target yaw rate of the present invention is the yaw rate when the vehicle body is relatively stable. In this way, based on the error between the actual yaw rate and the target yaw rate and the target rear-wheel limit corner, determining the target rear-wheel corner, and controlling the rear-wheel steering of the vehicle through the target rear-wheel corner can make the actual yaw rate of the vehicle reach or approach the above target yaw rate, which is beneficial to improving the vehicle stability.

[0158] Hereinafter, taking the fourth preset value as 0 as an example, how to determine the target yaw rate will be described.

[0159] In the above formulas 7 and 8 Substitute into formulas 7 and 8 respectively, and the following can be obtained:

[0160]

[0161] Let Substitute into the above formulas respectively, and the following can be obtained:

[0162]

[0163] After organizing the above two formulas respectively, the following can be obtained:

[0164]

[0165] After simplifying the above formulas, the following can be obtained:

[0166]

[0167] Among them, ωr_tar is the above target yaw rate, and σr_Tar represents the first rear-wheel corner calculated by an external system.

[0168] In formula 17:

[0169]

[0170] K represents the stability factor.

[0171] The calculation logic of the above σr_Tar is as follows:

[0172]

[0173] σf * k = σf - σr

[0174] σr_Tar = σf * (1 - k)

[0175] In the formula, k is the calibration coefficient. If k > 1, the rear wheel steering angle is in the same direction as the front wheel steering angle; if k < 1, the rear wheel steering angle is in the opposite direction to the front wheel steering angle; if k = 1, σr_Tar is 0 and no action is taken.

[0176] The above k value is related to the vehicle speed of the whole vehicle, and the k value is determined by calibration. Considering the factor of reducing the turning radius at low speed, the rear wheel steering angle should be in the opposite direction to the front wheel steering angle; considering the factor of vehicle body stability at high speed, the rear wheel steering angle should be in the same direction as the front wheel steering angle. Moreover, the calibration of the k value needs to consider the factor of the driving mode, and there are different calibrated k values under different driving modes. Generally, in the economic driving (Economic, abbreviated as eco) mode, considering driving comfort, the calibration of the k value should not be too radical; in the sport mode, considering the acceleration of the whole vehicle, it is necessary to respond to the driver's steering demand faster, and the calibrated k value can be appropriately adjusted to improve the lateral dynamic response of the whole vehicle. Generally, the k value slope in the sport mode should be higher than that in the economic mode.

[0177] Determining σr_Tar through the above formula can achieve reducing the turning radius at low speed and maintaining the vehicle body stability at high speed; moreover, by considering the driving mode of the whole vehicle and appropriately adjusting σr_Tar under different driving modes, different driving feelings can be achieved.

[0178] Optionally, the method further includes:

[0179] Judging whether the states of the vehicle all meet the target conditions;

[0180] When the states of the vehicle all meet the target conditions, it is determined that the vehicle is driving on a separated road surface; wherein, the target conditions include at least one of the following conditions:

[0181] Condition 1, TCS is activated. It can be judged whether TCS is activated based on the TCS activation flag bit. When the vehicle is driving on a separated road surface, TCS is activated to control the vehicle stability through the slip ratio. It can be seen that judging whether the vehicle is driving on a separated road surface based on whether TCS is activated has a certain degree of accuracy.

[0182] Condition 2: The absolute value of the wheel speed difference on both sides of the vehicle is greater than a first threshold value, and the first threshold value is greater than 0. Under a split road surface, generally, the wheel speed of the low-traction side wheels is higher than that of the high-traction side wheels. Based on this, it is possible to determine whether the vehicle is driving on a split road surface by the absolute value of the wheel speed difference.

[0183] Condition 3: The wheel acceleration of the low-traction side wheels of the vehicle is less than a second threshold value, and the second threshold value is less than 0. Under a split road surface, the TCS intervenes and needs to brake the low-traction side wheels. Based on this, it is possible to use whether the wheel acceleration of the low-traction side wheels is less than the second threshold value to determine whether the vehicle is driving on a split road surface.

[0184] Condition 4: The slip ratio of the low-traction side wheels of the vehicle is greater than a third threshold value, and the third threshold value is greater than 0. When the vehicle is driving on a split road surface, generally, the slip ratio of the low-traction side wheels is relatively large. Therefore, it is possible to determine whether the vehicle is driving on a split road surface based on whether the slip ratio of the low-traction side wheels is greater than the third threshold value. The following describes the calculation method of the slip ratio.

[0185] If the wheel speed > vehicle speed, the slip ratio Slip is determined by the following formula:

[0186]

[0187] If the vehicle speed > wheel speed, the slip ratio Slip is determined by the following formula:

[0188]

[0189] In the above formula for determining the slip ratio, whlSpd represents the wheel speed; vehSpd represents the vehicle speed of the whole vehicle.

[0190] Condition 5: The opening of the vehicle's accelerator pedal is greater than a fourth threshold value (the fourth threshold value is greater than 0), and the vehicle's brake pedal is not depressed. When Condition 5 is satisfied, the road surface condition may have changed, causing the driver to request to accelerate through the current road surface. Therefore, Condition 5 has certain reference significance for determining whether the vehicle has reached a split road surface.

[0191] Condition 6: The absolute value of the brake pressure difference on both sides of the vehicle is greater than a fifth threshold value (the fifth threshold value is greater than 0). When the vehicle is driving on a split road surface, the TCS intervenes and needs to brake the low-traction side wheels, and the brake pressures on the left and right wheels are different. Based on this, it is possible to use the absolute value of the brake pressure difference between the left and right sides to determine whether the vehicle is driving on a split road surface.

[0192] In some embodiments, in order to improve the accuracy of determining a split road surface, the target conditions may be set to include the six conditions from Condition 1 to Condition 6 described above.

[0193] Optionally, the method further includes:

[0194] When the vehicle is driving on a split road surface, determine the target slip ratio of the target axle and the target slip ratio of the low-adhesion-side wheel;

[0195] Determine the target axle speed of the target axle based on the target slip ratio of the target axle, and determine the target wheel speed of the low-adhesion-side wheel based on the target slip ratio of the low-adhesion-side wheel;

[0196] Determine the driving torque based on the error between the target axle speed and the actual axle speed of the target axle, and drive the target axle according to the driving torque;

[0197] Determine the braking torque of the low-adhesion-side wheel based on the error between the target wheel speed and the actual wheel speed of the low-adhesion-side wheel, and brake the low-adhesion-side wheel according to the braking torque.

[0198] In the case of a rear-axle drive vehicle, when the rear-axle driving torque > ground capacity, the rear axle is prone to slipping, and the whole vehicle has a tendency of oversteering. It is necessary to reduce the driving torque of the rear axle. Therefore, the above target axle is the rear axle.

[0199] In the case of a front-axle drive vehicle, when the front-axle driving torque > ground capacity, the front axle is prone to slipping, and the whole vehicle has a tendency of understeering. It is necessary to reduce the driving torque of the front axle. Therefore, the above target axle is the front axle.

[0200] In the embodiments of the present invention, when the vehicle is driving on a split road surface, in addition to controlling the rear-wheel steering angle, driving the target axle and braking the low-adhesion-side wheel at the same time is beneficial to further improve the lateral stability of the whole vehicle on the split road surface.

[0201] The above vehicle control method in the present invention can be applied to a vehicle control system. Refer to Figure 3 , Figure 3 is the architecture diagram of the vehicle control system, including a Vehicle State Estimation (VSE) module, a Rear Wheel System (RWS), and TCS.

[0202] Refer to Figure 4 As above, the VSE mainly obtains the reference vehicle speed and road surface adhesion coefficient of the vehicle through fusion processing of wheel speeds, steering angles, acceleration sensors, etc., and judges the split road surface based on the above target conditions, providing a basis for correctly calculating the target slip ratio and the actual slip ratio.

[0203] Refer to Figure 4 As above, the RWS is mainly used to receive the data sent by the VSE and calculate the target rear-wheel limit steering angle, the target yaw rate, and the target rear-wheel steering angle.

[0204] See Figure 4 , the above TCS is mainly used to receive the data sent by the VSE, calculate the target slip ratio, and correct the target slip ratio while considering unexpected risks such as oversteering or understeering of the vehicle. The target slip ratio control adopts a hierarchical method: the target slip ratio of the target axle is controlled by the motor torque (Motor Torque Control, abbreviated as MTC) controller; in the case of a split road surface, it is necessary to calculate the target slip ratio of the low-adhesion side wheels, and the target slip ratio of the low-adhesion side wheels is controlled separately by the brake torque (Brake Torque Control, abbreviated as BTC) controller.

[0205] The following gives an exemplary description of how the TCS determines the target slip ratio and how to drive and brake on a split road surface.

[0206] See Figure 5 , the basic slip ratio (vSlipTar Traction ) of the target axle is calculated by the MTC, and the target slip ratio (vSlipTar Traction ) of the target axle is obtained after multiple corrections to vSlipTar Constrain ; the target slip ratio of the low-adhesion side wheels is calculated by the BTC based on vSlipTar Traction

[0207] I. The MTC determines the target slip ratio of the target axle and calculates the target axle speed

[0208] (1) Calculate vSlipTar Traction by looking up a table:

[0209] vSlipTar Traction = map(mue, vehspd, splitflg)

[0210] In the formula, mue represents the road surface adhesion coefficient, vehspd represents the reference vehicle speed, and splitflg represents the flag bit of the split road surface.

[0211] (2) The MTC makes a first correction to vSlipTar Traction according to the oversteering and understeering degrees to obtain vSlipTar Stability :

[0212] vSlipTar Stability = vSlipTar Traction + fac

[0213] fac represents the correction amount. fac is calculated based on PID. Specifically, a second PID calculation is performed based on the error between the target yaw rate and the actual yaw rate, and the calculation result of the second PID is set as the slip ratio correction amount.

[0214] (3) MTC corrects vSlipTar according to the factors of hardware protection Stability to obtain vSlipTar Constrain .

[0215] vSlipTar Constrain = vSlipTar Stability + map(TTC)+ map(trample)

[0216] In the formula, TTC is the tire radius difference. When detecting and replacing the spare tire, the target slip ratio needs to be adjusted upward. trample is the axle jitter situation. When detecting axle jitter, the target slip ratio of the target axle needs to be adjusted appropriately. The calculation logic of trample is as follows:

[0217] trample = abs(axleSpd - filter9axleSpd)) > TBD

[0218] In the formula, abs represents taking the absolute value, AxleSpd represents the axle speed; Filter(axleSpd) represents the filtered axle speed; TBD represents the calibrated quantity, indicating the discretization degree of the sampling points.

[0219] (4) MTC determines the target axle speed vTarMTC:

[0220] vTarMTC = vSlipTar Constrain + vRefAxleSpd

[0221] In the formula, vRefAxleSpd represents the reference axle speed, which is calculated from the reference wheel speed.

[0222] II. BTC calculates the target slip ratio of the low - adhesion side wheel and calculates the target wheel speed vTarBTC

[0223] The BTC control target needs to be corrected based on the MTC control target, and the correction method is as follows:

[0224]

[0225] fac = map(mue, ay, axleSpd)

[0226]

[0227] Wherein, Mue represents the road surface adhesion coefficient; Ay represents the lateral acceleration collected by the imu; Axlespd represents the axle speed; and vRefWhlSpd represents the reference wheel speed.

[0228] III. MTC performs drive torque calculation

[0229] MTC performs a third PID calculation based on the error between the target axle speed and the actual axle speed of the target axle, obtains the drive torque of the target axle, and drives the target axle based on the drive torque of the target axle.

[0230] IV. BTC performs braking torque calculation

[0231] BTC performs a fourth PID calculation based on the error between the target wheel speed and the actual wheel speed of the low-adhesion side wheel, obtains the braking torque of the low-adhesion side wheel, and brakes the low-adhesion side wheel based on the braking torque.

[0232] In the vehicle control system of the present invention, when the vehicle is driving on a separated road surface, RWS can help the vehicle better adapt to road surface changes by controlling the rear wheel steering, avoiding loss of control caused by wheel slip on one side. Moreover, the application of rear wheel steering can significantly improve the acceleration performance of the vehicle while ensuring the lateral stability of the vehicle; under the separated road surface, the application of TCS maintains the vehicle's ability to utilize the ground as much as possible; in addition, under the separated road surface, through the control of RWS and TCS, the driver can not correct the steering wheel angle (front wheel angle) to keep the vehicle driving along the established trajectory, significantly improving the driving comfort of the driver.

[0233] It should be understood that the magnitudes of the sequence numbers of the steps in the above embodiments do not mean the order of execution. The execution order of each process should be determined according to its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

[0234] Figure 6 is a block diagram of a vehicle control device shown in an exemplary embodiment of the present invention. As Figure 6 shown, the exemplary vehicle control device includes:

[0235] A first acquisition module 610, when the vehicle is driving on a separated road surface, acquires the dynamic parameters of the vehicle, and the dynamic parameters include the actual yaw rate of the vehicle;

[0236] A first determination module 620, configured to determine a target rear wheel limit angle and a target yaw rate according to the dynamic parameters of the vehicle;

[0237] A second determination module 630, configured to determine a target rear wheel angle based on an error between the actual yaw rate and the target yaw rate, and the target rear wheel limit angle, wherein an absolute value of the target rear wheel angle is less than the target rear wheel limit angle;

[0238] A first control module 640, configured to control rear wheel steering of the vehicle based on the target rear wheel angle.

[0239] In an embodiment of the present invention, the first determination module 620 is specifically configured to:

[0240] Determine a first rear wheel limit angle based on a first preset condition, a lateral force balance equation, and dynamic parameters of the vehicle, where the first preset condition includes that both the lateral acceleration and the sideslip angle of the vehicle are equal to a first preset value;

[0241] Determine a second rear wheel limit angle based on a second preset condition, a lateral moment balance equation, and dynamic parameters of the vehicle, where the second preset condition includes that both the yaw acceleration and the sideslip angle of the vehicle are equal to a second preset value;

[0242] Determine the target rear wheel limit angle as the rear wheel limit angle with the smallest absolute value among multiple rear wheel limit angles, where the multiple rear wheel limit angles include the first rear wheel limit angle and the second rear wheel limit angle;

[0243] Wherein, both the lateral moment balance equation and the lateral force balance equation are equations determined based on a two-degree-of-freedom vehicle model.

[0244] In an embodiment of the present invention, the first determination module 620 is further specifically configured to:

[0245] Determine the third rear wheel limit angle based on a third preset condition, the lateral force balance equation, the lateral moment balance equation, and dynamic parameters of the vehicle, where the third preset condition includes that the sideslip angle rate, the sideslip angle, and the yaw acceleration of the vehicle are all equal to a third preset value, and the multiple rear wheel limit angles further include the third rear wheel limit angle.

[0246] In an embodiment of the present invention, the multiple rear wheel limit angles further include the maximum rear wheel angle of the vehicle.

[0247] In an embodiment of the present invention, the first determination module 620 is further specifically configured to:

[0248] Determine the target yaw rate based on a fourth preset condition, dynamic parameters of the vehicle, and a two-degree-of-freedom vehicle model, where the fourth preset condition includes that both the yaw acceleration and the lateral acceleration of the vehicle are equal to a fourth preset value.

[0249] In one embodiment of the present invention, the vehicle control device further includes:

[0250] A judgment module, configured to judge whether the states of the vehicle all meet the target conditions;

[0251] A third determination module, configured to determine that the vehicle is traveling on a separated road surface when the states of the vehicle all meet the target conditions; wherein, the target conditions include at least one of the following conditions:

[0252] The TCS of the vehicle has been activated;

[0253] The absolute value of the wheel speed difference between both sides of the vehicle is greater than a first threshold;

[0254] The wheel acceleration of the low-adhesion side wheel of the vehicle is less than a second threshold;

[0255] The slip ratio of the low-adhesion side wheel of the vehicle is greater than a third threshold;

[0256] The opening degree of the throttle pedal of the vehicle is greater than a fourth threshold, and the brake pedal of the vehicle is not depressed;

[0257] The absolute value of the brake pressure difference between both sides of the vehicle is greater than a fifth threshold.

[0258] In one embodiment of the present invention, the vehicle control device further includes:

[0259] A fourth determination module, configured to determine the target slip ratio of the target axle and the target slip ratio of the low-adhesion side wheel when the vehicle is traveling on a separated road surface;

[0260] A fifth determination module, configured to determine the target axle speed of the target axle based on the target slip ratio of the target axle, and determine the target wheel speed of the low-adhesion side wheel based on the target slip ratio of the low-adhesion side wheel;

[0261] A second control module, configured to determine the driving torque based on the error between the target axle speed and the actual axle speed of the target axle, and drive the target axle according to the driving torque;

[0262] A third control module, configured to determine the braking torque of the low-adhesion side wheel based on the error between the target wheel speed and the actual wheel speed of the low-adhesion side wheel, and brake the low-adhesion side wheel according to the braking torque.

[0263] It should be noted that the vehicle control device provided in the above embodiments and the vehicle control method provided in the above embodiments belong to the same concept. The specific ways in which each module and unit perform operations have been described in detail in the method embodiments and will not be elaborated here. In practical applications, the vehicle control device provided in the above embodiments can, according to needs, allocate the above functions to different functional modules, that is, divide the internal structure of the device into different functional modules to complete all or part of the functions described above. This is not limited here either.

[0264] An embodiment of the present invention also provides an electronic device, including: one or more processors; a storage device for storing one or more programs, which, when executed by the one or more processors, cause the electronic device to implement the vehicle control method provided in each of the above embodiments.

[0265] Figure 7 The structural schematic diagram of a computer system of an electronic device suitable for implementing the embodiments of the present invention is shown. It should be noted that Figure 7 The computer system 700 of the electronic device shown is only an example and should not impose any limitations on the functions and usage scope of the embodiments of the present invention.

[0266] As Figure 7 shown, the computer system 700 includes a central processing unit (CPU) 701, which can perform various appropriate actions and processes according to the program stored in the read-only memory (ROM) 702 or the program loaded from the storage section 708 into the random access memory (RAM) 703, such as executing the method described in the above embodiments. In the RAM 703, various programs and data required for system operation are also stored. The CPU 701, ROM 702, and RAM 703 are connected to each other through a bus 704. The input / output (I / O) interface 705 is also connected to the bus 704.

[0267] The following components are connected to the I / O interface 705: an input section 706 including a keyboard, a mouse, etc.; an output section 707 including a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 708 including a hard disk, etc.; and a communication section 709 including a network interface card such as a local area network (LAN) card, a modem, etc. The communication section 709 performs communication processing via a network such as the Internet. A drive 710 is also connected to the I / O interface 705 as required. A removable medium 711, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 710 as required so that a computer program read from the same can be installed into the storage section 708 as required.

[0268] Specifically, according to an embodiment of the present invention, the processes described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present invention includes a computer program product that includes a computer program carried on a computer-readable medium, and the computer program includes a computer program for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network via the communication section 709, and / or installed from the removable medium 711. When the computer program is executed by a central processing unit (CPU) 701, various functions defined in the system of the present invention are executed.

[0269] It should be noted that the computer-readable medium shown in the embodiments of the present invention can be a computer-readable signal medium, a computer-readable storage medium, or any combination of the two. A computer-readable storage medium can be, for example, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples of the computer-readable storage medium may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present invention, a computer-readable signal medium can include a data signal propagated in a baseband or as part of a carrier wave, which carries a computer-readable computer program. Such a propagated data signal can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. A computer-readable signal medium can also be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The computer program contained on the computer-readable medium can be transmitted using any appropriate medium, including but not limited to: wireless, wired, etc., or any suitable combination of the above.

[0270] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to various embodiments of the present invention. Among them, each block in the flowchart or block diagram can represent a module, a program segment, or a part of code, and the above module, program segment, or part of code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than marked in the accompanying drawings. For example, two consecutive blocks shown may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram or flowchart, as well as the combination of blocks in the block diagram or flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or operations, or can be implemented by a combination of dedicated hardware and computer instructions.

[0271] The units involved in the embodiments of the present invention can be implemented in software or in hardware, and the described units can also be provided in a processor. Among them, the names of these units do not, in some cases, constitute a limitation on the unit itself.

[0272] Another aspect of the present invention further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor of a computer, the computer is caused to execute the vehicle control method as described above. The computer-readable storage medium can be included in the electronic device described in the above embodiments, or can exist alone without being assembled into the electronic device.

[0273] Another aspect of the present invention further provides a computer program product or a computer program, which includes computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes the vehicle control method provided in the above various embodiments.

[0274] The above embodiments are only used to exemplarily illustrate the principles and effects of the present invention, rather than to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A vehicle control method, characterized in that: include: When the vehicle is traveling on a separated road, obtaining dynamic parameters of the vehicle, the dynamic parameters including an actual yaw rate of the vehicle; Determining a target rear wheel limit turning angle and a target yaw angular velocity according to the dynamic parameters of the vehicle; determining a target rear wheel turning angle based on an error between the actual yaw rate and the target yaw rate, and the target rear wheel limit turning angle, wherein an absolute value of the target rear wheel turning angle is smaller than the target rear wheel limit turning angle; Rear wheel steering of the vehicle is controlled based on the target rear wheel steering angle.

2. The vehicle control method according to claim 1, characterized in that: Determining a target rear wheel limiting turning angle according to the dynamic parameters of the vehicle includes: Determining a first rear wheel limiting turning angle based on a first preset condition, a lateral force balance equation and a dynamic parameter of the vehicle, wherein the first preset condition includes that the lateral acceleration and the center of mass sideslip angle of the vehicle are both equal to a first preset value; Determining a second rear wheel limit turning angle based on a second preset condition, a lateral moment balance equation, and a dynamic parameter of the vehicle, wherein the second preset condition includes that the yaw angular acceleration and the center of mass sideslip angle of the vehicle are both equal to a second preset value; determining a rear wheel limited turning angle with the smallest absolute value among a plurality of rear wheel limited turning angles as the target rear wheel limited turning angle, the plurality of rear wheel limited turning angles including the first rear wheel limited turning angle and the second rear wheel limited turning angle; Among them, the lateral moment balance equation and the lateral force balance equation are both equations determined based on a two-degree-of-freedom vehicle model.

3. The vehicle control method according to claim 2, characterized in that: The method further comprises: The third rear wheel limited turning angle is determined based on a third preset condition, the lateral force balance equation, the lateral torque balance equation and the dynamic parameters of the vehicle. The third preset condition includes that the vehicle's center of mass sideslip angle change rate, center of mass sideslip angle and yaw angular acceleration are all equal to a third preset value, and the multiple rear wheel limited turning angles also include the third rear wheel limited turning angle.

4. The vehicle control method according to claim 2 or 3, characterized in that: The plurality of rear wheel limiting turning angles also include a maximum rear wheel turning angle of the vehicle.

5. The vehicle control method according to claim 1, characterized in that: Determining a target yaw rate according to the dynamic parameters of the vehicle includes: The target yaw rate is determined based on a fourth preset condition, the dynamic parameters of the vehicle and a two-degree-of-freedom vehicle model. The fourth preset condition includes that the yaw acceleration and the lateral acceleration of the vehicle are both equal to a fourth preset value.

6. The vehicle control method according to claim 1, characterized in that: The method further comprises: Determining whether the states of the vehicles all meet the target conditions; When the states of the vehicles all meet the target conditions, it is determined that the vehicle is traveling on a separated road; wherein the target conditions include at least one of the following conditions: the traction control system of said vehicle is activated; The absolute value of the wheel speed difference between the two sides of the vehicle is greater than a first threshold; The wheel acceleration of the low-side wheel of the vehicle is less than a second threshold; The slip rate of the low-side wheel of the vehicle is greater than a third threshold; The accelerator pedal opening of the vehicle is greater than a fourth threshold, and the brake pedal of the vehicle is not stepped on; The absolute value of the brake pressure difference between the two sides of the vehicle is greater than a fifth threshold value.

7. The vehicle control method according to claim 1, characterized in that: The method further comprises: determining a target slip ratio of a target axle and a target slip ratio of a low-side wheel when the vehicle is traveling on a separated road surface; determining a target shaft speed of the target shaft based on a target slip ratio of the target shaft, and determining a target wheel speed of the low-addition-side wheel based on a target slip ratio of the low-addition-side wheel; determining a driving torque based on an error between the target shaft speed and an actual shaft speed of the target shaft, and driving the target shaft according to the driving torque; Based on an error between the target wheel speed and an actual wheel speed of the low-adjustment wheel, a braking torque is determined, and the low-adjustment wheel is braked according to the braking torque.

8. A vehicle control device, characterized in that: include: A first acquisition module, configured to acquire dynamic parameters of the vehicle when the vehicle is traveling on a separated road, wherein the dynamic parameters include an actual yaw angular velocity of the vehicle; A first determination module, used for determining a target rear wheel limit turning angle and a target yaw angular velocity according to the dynamic parameters of the vehicle; a second determining module, configured to determine a target rear wheel turning angle based on an error between the actual yaw angular velocity and the target yaw angular velocity, and the rear wheel limit turning angle, wherein an absolute value of the target rear wheel turning angle is smaller than the target rear wheel limit turning angle; The first control module is used to control the rear wheel steering of the vehicle based on the target rear wheel steering angle.

9. A device, characterized in that: include: one or more processors and memory, A computer program is stored in the memory, and when the one or more processors execute the computer program, the device executes the vehicle control method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: A computer program is stored thereon, which, when executed by one or more processors, causes the device to perform the vehicle control method as claimed in any one of claims 1 to 7.

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