A vehicle rear-wheel steering control method and device

Abstract

The present application discloses a vehicle rear-wheel steering control method and device. Among them, the vehicle rear-wheel steering control method can be applied to the field of vehicle control technology. The method includes: in response to a traction control instruction, identifying the road surface type of the current driving road surface of the target vehicle to obtain a road surface type identification result; when the road surface type identification result indicates a target type road surface, determining a target steering based on the direction of the target side wheels of the target vehicle in the horizontal direction relative to the target vehicle; judging whether the driving instability degree of the target vehicle reaches a preset instability degree based on the target steering and the current steering wheel angle; when the driving instability degree reaches the preset instability degree, determining the target angle of the rear wheels of the target vehicle at the current control moment based on the target steering and a basic angle; and controlling the rear-wheel steering of the target vehicle according to a preset duration based on the target angle. The present application can enable the vehicle to maintain stability on an oncoming road surface while improving the acceleration performance of the vehicle.

Description

Technical Field

[0001] This application relates to the field of computer technology, and particularly to a method and device for controlling the rear-wheel steering of a vehicle. Background Art

[0002] When a vehicle starts with full throttle on a two-way road surface or accelerates at low speed with full throttle, in order to ensure the stable driving of the vehicle, the traditional traction control system needs greater intervention control, thereby reducing the acceleration of the vehicle, or the driver needs to intervene more in the direction to keep the vehicle driving stably in the lane.

[0003] In terms of controlling the dynamic stability of a vehicle, the active rear-wheel steering system can play an important role. Its advantage is that the steering of the rear wheels is controlled by a computer, which can be more accurate, faster, and can determine the rear-wheel steering according to the driving conditions of the vehicle.

[0004] However, currently, the rear-wheel steering is only controlled by its own controller and does not act in cooperation with the traction control system. In corresponding working conditions, it cannot be well utilized to make the vehicle more stable or accelerate faster. Summary of the Invention

[0005] In order to solve the problems of the prior art, the embodiments of this application provide a method and device for controlling the rear-wheel steering of a vehicle. The technical solutions are as follows:

[0006] On the one hand, a method for controlling the rear-wheel steering of a vehicle is provided. The method includes:

[0007] Respond to a traction control instruction, identify the road surface type of the current driving road surface of the target vehicle, and obtain a road surface type identification result;

[0008] When the road surface type identification result indicates a target type road surface, determine a target steering based on the direction of the target side wheels of the target vehicle in the horizontal direction relative to the target vehicle; the target type road surface refers to a road surface with inconsistent adhesion coefficients of the left and right wheels of the vehicle; the adhesion coefficient of the target side wheels to the current driving road surface is less than the adhesion coefficient of the other side wheels of the target vehicle to the current driving road surface;

[0009] Based on the target steering and the current steering wheel angle, determine whether the driving instability degree of the target vehicle reaches a preset instability degree;

[0010] When the driving instability degree reaches the preset instability degree, determine the target angle of the rear wheels of the target vehicle at the current control moment based on the target steering and the base angle; the base angle is the angle of the rear wheels of the target vehicle at the previous control moment;

[0011] Based on the target steering angle, control the rear-wheel steering of the target vehicle for a preset duration.

[0012] On the other hand, a vehicle rear-wheel steering control device is provided, and the device includes:

[0013] A road surface recognition module, configured to recognize the road surface type of the current driving road surface of the target vehicle in response to a traction control instruction, and obtain a road surface type recognition result;

[0014] A steering determination module, configured to determine a target steering based on the direction of the target side wheels of the target vehicle in the horizontal direction relative to the target vehicle when the road surface type recognition result indicates a target type road surface; the target type road surface refers to a road surface with inconsistent adhesion coefficients of the left and right wheels of the vehicle; the adhesion coefficient of the target side wheels to the current driving road surface is less than the adhesion coefficient of the other side wheels of the target vehicle to the current driving road surface;

[0015] A first stability judgment module, configured to judge whether the driving instability degree of the target vehicle reaches a preset instability degree based on the target steering and the current steering wheel angle;

[0016] A first steering angle determination module, configured to determine the target steering angle of the rear wheels of the target vehicle at the current control moment based on the target steering and a base steering angle when the driving instability degree reaches the preset instability degree; the base steering angle is the steering angle of the rear wheels of the target vehicle at the previous control moment;

[0017] A first rear-wheel control module, configured to control the rear-wheel steering of the target vehicle for a preset duration based on the target steering angle.

[0018] In an exemplary embodiment, the first stability judgment module includes:

[0019] A first steering wheel steering module, configured to determine the current steering wheel steering of the target vehicle based on the current steering wheel angle;

[0020] An angle judgment module, configured to judge whether the absolute value of the current steering wheel angle is greater than or equal to a preset steering wheel angle threshold when the current steering wheel steering is inconsistent with the target steering;

[0021] A first instability determination module, configured to determine that the driving instability degree of the target vehicle reaches the preset instability degree when the absolute value of the current steering wheel angle is greater than or equal to the preset steering wheel angle threshold.

[0022] In an exemplary embodiment, the device further includes a second stability determination module for determining whether the driving instability degree of the target vehicle reaches the preset instability degree based on the steering wheel angle change rate. The second stability determination module includes:

[0023] A change rate acquisition module, configured to acquire the current steering wheel angle change rate when the absolute value of the current steering wheel angle is less than the preset steering wheel angle threshold;

[0024] A change rate determination module, configured to determine whether the absolute value of the current steering wheel angle change rate is less than the preset steering wheel angle change rate threshold;

[0025] A second instability determination module, configured to determine that the driving instability degree of the target vehicle reaches the preset instability degree when the absolute value of the current steering wheel angle change rate is less than the preset steering wheel angle change rate threshold.

[0026] In an exemplary embodiment, the device further includes a steering determination module for determining the rear-wheel steering at the previous control moment when the instability degree is not satisfied. The steering determination module includes:

[0027] A basic steering module, configured to determine the rear-wheel steering of the target vehicle at the previous control moment to obtain the basic steering when the driving instability degree does not reach the preset instability degree;

[0028] A second rear-wheel control module, configured to control the rear wheels of the target vehicle not to steer when the basic steering is inconsistent with the target steering.

[0029] In an exemplary embodiment, the device further includes a duration determination module for determining whether the rear-wheel steering duration reaches the preset duration. The duration determination module includes:

[0030] A steering duration module, configured to determine the duration from the start moment of the rear-wheel steering of the target vehicle at the previous control moment to the current control moment to obtain the steering duration when the basic steering is consistent with the target steering;

[0031] A second angle determination module, configured to determine the target angle of the rear wheels of the target vehicle at the current control moment based on the target steering and the basic angle when the steering duration is less than or equal to the preset duration;

[0032] A third rear-wheel control module, configured to control the rear wheels of the target vehicle to steer according to the preset duration based on the target angle.

[0033] In an exemplary embodiment, the device further includes a fourth rear-wheel control module configured to control the rear wheels not to steer when the rear-wheel steering duration reaches a preset duration. The fourth rear-wheel control module includes:

[0034] The fourth rear-wheel control module is configured to control the rear wheels of the target vehicle not to steer when the steering duration is greater than the preset duration.

[0035] In an exemplary embodiment, the first corner determination module or the second corner determination module includes:

[0036] A data acquisition module configured to determine a current braking control intervention torque based on the road surface type recognition result; and acquire a basic change rate of the rear-wheel corner corresponding to the current braking control intervention torque.

[0037] A second steering wheel steering module configured to determine a reference steering of the current steering wheel based on the opposite direction of the target steering; and determine the current steering of the steering wheel of the target vehicle based on the current steering wheel angle.

[0038] A first corner change rate module configured to determine a first corner change rate of the rear wheels of the target vehicle based on a current braking control intervention torque change rate, a current steering wheel angle change rate, a current yaw angle change rate, and the basic change rate of the rear-wheel corner when the current steering of the steering wheel is inconsistent with the reference steering.

[0039] A first target corner module configured to determine the target corner based on the basic corner and the first corner change rate.

[0040] In an exemplary embodiment, the first corner change rate module includes:

[0041] A weight acquisition module configured to acquire a first weight corresponding to the current braking control intervention torque change rate, a second weight corresponding to the current steering wheel angle change rate, and a third weight corresponding to the current yaw angle change rate; the first weight is a positive value, the second weight is a negative value, and the third weight is a negative value.

[0042] A weighted summation module configured to perform weighted summation based on the current braking control intervention torque change rate and the first weight, the current steering wheel angle change rate and the second weight, and the current yaw angle change rate and the third weight to obtain the first corner change rate.

[0043] In an exemplary embodiment, the device further includes a third corner determination module configured to calculate a target corner when the current steering of the steering wheel is consistent with the reference steering. The third corner determination module includes:

[0044] A coefficient acquisition module, configured to acquire a rear-wheel steering coefficient corresponding to a current steering wheel angle when the current steering wheel steering is consistent with the reference steering; the rear-wheel steering coefficient is greater than or equal to a preset value;

[0045] A second corner change rate module, configured to obtain a second corner change rate by multiplying the first corner change rate and the rear-wheel steering coefficient;

[0046] A second target corner module, configured to determine the target corner based on the base corner and the second corner change rate.

[0047] In an exemplary embodiment, the device further includes a coefficient judgment module for judging whether the operation symbol of the rear-wheel steering coefficient is correct. The coefficient judgment module includes:

[0048] A coefficient judgment module, configured to determine that the target corner is zero when the operation symbol of the rear-wheel corner base change rate is inconsistent with the operation symbol of the current braking control intervention torque.

[0049] On the other hand, an electronic device is provided, including a processor and a memory. At least one instruction or at least one program segment is stored in the memory. The at least one instruction or the at least one program segment is loaded and executed by the processor to implement the vehicle rear-wheel steering control method in any of the above aspects.

[0050] On the other hand, a computer-readable storage medium is provided. At least one instruction or at least one program segment is stored in the computer-readable storage medium. The at least one instruction or the at least one program segment is loaded and executed by a processor to implement the vehicle rear-wheel steering control method in any of the above aspects.

[0051] On the other hand, a computer program product or a computer program is provided. The computer program product or the computer program includes computer instructions, and the computer instructions are stored in a computer-readable storage medium. A processor of an electronic device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the electronic device executes the vehicle rear-wheel steering control method in any of the above aspects.

[0052] In the embodiments of the present application, the traction control system calculates the instability degree of the vehicle on a split road surface, judges the rear-wheel steering based on the steering wheel steering and the identification of the left and right road surface adhesion coefficients, and then calculates the rear-wheel corner. By controlling the rear-wheel steering, the dynamic driving attitude of the vehicle is changed, and the vehicle can be better controlled on the split road surface. While keeping the vehicle stable with less steering wheel intervention, the acceleration performance of the vehicle is improved. Description of the Drawings

[0053] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0054] Figure 1 is a schematic flowchart of a method for controlling the rear-wheel steering of a vehicle provided by an embodiment of the present application;

[0055] Figure 2 is a schematic flowchart of a method for judging the degree of vehicle driving instability provided by an embodiment of the present application;

[0056] Figure 3 is a schematic flowchart of a method for determining the rear-wheel steering angle of a vehicle provided by an embodiment of the present application;

[0057] Figure 4 is a schematic flowchart of a method for judging the correctness of the basic change rate of the rear-wheel steering angle provided by an embodiment of the present application;

[0058] Figure 5 is a schematic flowchart of a method for calculating the change rate of the rear-wheel steering angle of a vehicle provided by an embodiment of the present application;

[0059] Figure 6 is a structural block diagram of a vehicle rear-wheel steering control device provided by an embodiment of the present application;

[0060] Figure 7 is a hardware structural block diagram of an electronic device provided by an embodiment of the present application. Detailed implementation manners

[0061] The following will clearly and completely describe the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0062] It should be noted that in the description of the present application, the terms "first", "second", etc. in the specification, claims and the above drawings are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present application described here can be implemented in an order other than those illustrated or described here. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or server including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0063] It can be understood that in the specific implementation of the present application, when it comes to data related to user information, etc., when the above embodiments of the present application are applied to specific products or technologies, user permission or consent needs to be obtained, and the collection, use and processing of relevant data need to comply with relevant laws, regulations and standards of relevant countries and regions.

[0064] Please refer to Figure 1 , which shows a schematic flowchart of a method for controlling the rear-wheel steering of a vehicle provided by an embodiment of the present application. It should be noted that this specification provides the method operation steps as described in the embodiment or flowchart, but based on routine or non-creative labor, more or fewer operation steps may be included. The order of steps listed in the embodiment is only one way among the execution orders of numerous steps, and does not represent the only execution order. When the actual system or product is executed, it can be executed in the order of the method shown in the embodiment or the drawings, or executed in parallel (for example, in an environment of parallel processors or multi-threaded processing). Specifically, as Figure 1 shown, the method may include:

[0065] S101, in response to a traction control instruction, identify the road surface type of the current driving road surface of the target vehicle to obtain a road surface type identification result.

[0066] Among them, the traction control instruction is an instruction triggered by the vehicle under harsh conditions (such as the presence of gravel, rain, ice and snow, etc. on the vehicle driving road surface), and is an instruction for the traction control system to control the vehicle traction, so that the vehicle can obtain the best traction under various driving conditions.

[0067] Among them, road surface type recognition refers to recognizing whether the current driving road surface of the target vehicle is a split road surface, which is executed by the control device of the traction control system after the traction control instruction of the target vehicle is triggered. In specific implementation, the traction control system recognizes the adhesion coefficients of the left and right wheels of the target vehicle with the current driving road surface. If the adhesion coefficients of the left and right wheels with the current driving road surface are inconsistent, then the current driving road surface is a split road surface; the split road surface can also be recognized through other means such as traffic signs.

[0068] S103, determine whether the road surface type recognition result indicates a target type road surface; the target type road surface refers to a road surface with inconsistent adhesion coefficients of the left and right wheels of the vehicle.

[0069] Specifically, if the judgment result is yes, step S105 can be executed; conversely, if the judgment result is no, step S1017 can be executed.

[0070] Among them, the road surface type recognition result is the basis for how much braking control intervention torque the traction control system exerts on the vehicle, and it is also the basis for the control device of the traction control system to calculate whether it is necessary to assist in controlling the vehicle stability through rear-wheel steering. Specifically, if it is recognized that the difference in the adhesion coefficients of the left and right wheels with the current driving road surface is relatively large, the braking control intervention torque exerted by the traction control system on the vehicle is also relatively large. In this case, it is necessary to further judge whether to control the rear-wheel steering; if it is recognized that the current driving road surface is not a split road surface, how much braking control intervention torque the traction control system exerts on the vehicle requires its control device to make a comprehensive calculation and judgment based on relevant factors such as the current road conditions and slip ratio. In this case, the vehicle can maintain stable driving only by the braking control intervention torque exerted by the traction control system on the vehicle, without the need to control the rear-wheel steering.

[0071] S105, determine the target steering based on the direction of the target side wheels of the target vehicle in the horizontal direction relative to the target vehicle; the adhesion coefficient of the target side wheels with the current driving road surface is less than the adhesion coefficient of the other side wheels of the target vehicle with the current driving road surface.

[0072] Among them, the target steering is the direction of the wheel with a lower adhesion coefficient with the current driving road surface relative to the target vehicle. Specifically, if the road surface type recognition result indicates that the adhesion coefficient of the left wheels of the target vehicle with the current driving road surface is less than the adhesion coefficient of the right wheels with the current driving road surface, then the target steering is left; if the road surface type recognition result indicates that the adhesion coefficient of the right wheels of the target vehicle with the current driving road surface is less than the adhesion coefficient of the left wheels with the current driving road surface, then the target steering is right.

[0073] S107. Based on the target steering and the current steering wheel angle, determine whether the driving instability degree of the target vehicle reaches a preset instability degree.

[0074] Specifically, if the judgment result is yes, step S109 can be executed; on the contrary, if the judgment result is no, step S1013 can be executed.

[0075] Among them, the current steering wheel angle is the rotation angle and rotation direction of the current position of the steering wheel of the target vehicle relative to the initial position of the steering wheel. Specifically, when the rotation direction of the steering wheel is inconsistent with the target steering and the rotation angle is large, the traction control system believes that the driving instability degree of the target vehicle reaches the level that requires the rear-wheel steering to cooperate with the traction control to maintain the stable driving of the vehicle.

[0076] Among them, the driving instability degree is reflected by the control condition of the steering wheel when the target vehicle is driving on a two-way road. Specifically, when the rotation direction of the steering wheel is inconsistent with the target steering, the larger the rotation angle of the steering wheel, the more unstable the vehicle driving.

[0077] Among them, the preset driving instability degree is a threshold value preset for the driving instability degree of the vehicle, which is used for the traction control system to judge whether it is necessary to control the rear-wheel steering to cooperate with the traction control system to maintain the stable driving of the vehicle. Specifically, when the driving instability degree reaches the preset driving instability degree, it is necessary to control the rear-wheel steering; when the driving instability degree does not reach the preset driving instability degree, it is not necessary to control the rear-wheel steering.

[0078] In an exemplary embodiment, as Figure 2 shown, it is a schematic flowchart of a method for judging the driving instability degree of a vehicle provided by an embodiment of the present application. The above step S107 may include:

[0079] S201. Determine the current steering of the target vehicle based on the current steering wheel angle.

[0080] Among them, the current steering is the rotation direction of the current position of the steering wheel of the target vehicle relative to the initial position of the steering wheel. In specific implementation, the current steering is represented by the positive or negative value of the current steering wheel angle. For example, when the current steering is to the right, the current steering wheel angle is a positive value; when the current steering is to the left, the current steering wheel angle is a negative value.

[0081] S203. Judge whether the current steering is consistent with the target steering.

[0082] Specifically, if the judgment result is no, step S205 can be executed; on the contrary, if the judgment result is yes, step S1013 can be executed.

[0083] In specific implementation, when the target steering is to the left, that is, the adhesion coefficient between the left wheel of the target vehicle and the current driving road surface is less than the adhesion coefficient between the right wheel and the current driving road surface, if the current steering wheel is steered to the right, that is, the current steering wheel angle is positive (in accordance with the aforementioned operation symbol representation standard of the current steering wheel angle), then the current steering wheel steering is inconsistent with the target steering, that is, the current steering wheel rotates towards the high-adhesion side or remains in the initial position (the steering wheel angle is 0). In this case, it is necessary to continue to determine whether the current steering wheel angle is large; similarly, when the target steering is to the left, if the current steering wheel is steered to the left, that is, the current steering wheel angle is negative (in accordance with the aforementioned operation symbol representation standard of the current steering wheel angle), then the current steering wheel steering is consistent with the target steering, that is, the current steering wheel rotates towards the low-adhesion side. In this case, the vehicle is less likely to skid. Therefore, at the current control moment, it is not necessary to control the rear-wheel steering, but it is necessary to determine whether the rear-wheel control action at the previous control moment needs to continue.

[0084] S205, determine whether the absolute value of the current steering wheel angle is greater than or equal to a preset steering wheel angle threshold.

[0085] Specifically, if the judgment result is yes, step S109 can be executed; conversely, if the judgment result is no, step S207 can be executed.

[0086] Among them, the absolute value of the current steering wheel angle is the rotation angle of the current position of the steering wheel of the target vehicle relative to the initial position of the steering wheel.

[0087] Among them, the preset steering wheel angle threshold is a reference value for the traction control system to determine whether the current steering wheel angle is large. Specifically, when the current steering wheel steering is inconsistent with the target steering, if the absolute value of the current steering wheel angle is greater than or equal to the preset steering wheel angle threshold, it is considered that the current steering wheel angle is large, and the driving instability degree of the target vehicle reaches the preset instability degree, and it is necessary to control the rear-wheel steering; if the absolute value of the current steering wheel angle is less than the preset steering wheel angle threshold, it is not considered that the current steering wheel angle is large, and the driving instability degree of the target vehicle does not reach the preset instability degree, and it is necessary to further determine the instability degree of the target vehicle based on the current steering wheel angle change rate.

[0088] In specific implementation, according to the aforementioned standard for representing the operation symbol of the current steering wheel angle, when the target steering is to the left, that is, when the adhesion coefficient between the left wheel of the target vehicle and the current driving road surface is less than the adhesion coefficient between the right wheel and the current driving road surface, when the current steering wheel angle is positive, the preset steering wheel angle threshold is positive. If the current steering wheel angle is greater than or equal to the preset steering wheel angle threshold, it is considered that the current steering wheel angle is large. In this case, the target vehicle is prone to skidding, and the driving instability degree of the target vehicle reaches the preset instability degree, and the rear-wheel steering needs to be controlled; when the target steering is to the right, that is, when the adhesion coefficient between the right wheel of the target vehicle and the current driving road surface is less than the adhesion coefficient between the left wheel and the current driving road surface, when the current steering wheel angle is negative, the preset steering wheel angle threshold is negative. If the current steering wheel angle is less than or equal to the preset steering wheel angle threshold, it is considered that the current steering wheel angle is large. In this case, the target vehicle is prone to skidding, and the driving instability degree of the target vehicle reaches the preset instability degree, and the rear-wheel steering needs to be controlled.

[0089] S207. Obtain the current steering wheel angle change rate.

[0090] Among them, the current steering wheel angle change rate is the change speed of the current steering wheel angle of the target vehicle. In specific implementation, dividing the difference between the current steering wheel angle and the steering wheel angle at the previous control moment by the operation period of the traction control system can obtain the current steering wheel angle change rate. Among them, the previous control moment is the start moment of the previous operation period of the traction control system.

[0091] S209. Determine whether the absolute value of the current steering wheel angle change rate is less than the preset steering wheel angle change rate threshold.

[0092] Specifically, if the judgment result is yes, step S109 can be executed; on the contrary, if the judgment result is no, step S1013 can be executed.

[0093] Among them, the absolute value of the current steering wheel angle change rate represents the change amount of the current steering wheel angle compared with the steering wheel angle at the previous control moment. Specifically, if the current steering wheel angle change rate is positive, it means that the current steering wheel angle is increasing compared with the steering wheel angle at the previous control moment; if the current steering wheel angle change rate is negative, it means that the current steering wheel angle is decreasing compared with the steering wheel angle at the previous control moment.

[0094] Among them, the preset steering wheel angle change rate threshold is a reference value for the traction control system to judge the instability degree of the target vehicle based on the current steering wheel angle change rate. Specifically, when the absolute value of the current steering wheel angle is less than the preset steering wheel angle threshold, but the absolute value of the current steering wheel angle change rate is less than the preset steering wheel angle change rate, it indicates that the vehicle driving instability degree at the current control moment is close to that when the absolute value of the steering wheel angle is larger. The traction control system believes that it is necessary to continue to control the rear wheels to cooperate to maintain vehicle stability. Therefore, this situation is determined that the vehicle driving instability degree at the current control moment reaches the preset instability degree; on the contrary, when the absolute value of the current steering wheel angle is less than the preset steering wheel angle threshold, but the absolute value of the current steering wheel angle change rate is greater than or equal to the preset steering wheel angle change rate, it indicates that the vehicle driving instability degree at the current control moment is far from that when the absolute value of the steering wheel angle is larger. Therefore, it is determined that there is no need to control the rear wheel steering at the current control moment, and it is necessary to judge whether the rear wheel control action at the previous control moment needs to continue.

[0095] In specific implementation, according to the aforementioned standard for representing the operation symbol of the current steering wheel angle, when the target steering is to the left, that is, the adhesion coefficient between the left wheels of the target vehicle and the current driving road surface is less than the adhesion coefficient between the right wheels and the current driving road surface, when the current steering wheel angle is positive, the preset steering wheel angle threshold is positive. If the current steering wheel angle is less than the preset steering wheel angle threshold, then it is required that the decrease in the current steering wheel angle compared to the previous control moment is not large. Therefore, both the current steering wheel angle change rate and the preset steering wheel angle change rate are negative. If the current steering wheel angle change rate is greater than the preset steering wheel angle change rate, it is considered that the vehicle driving instability degree at the current control moment reaches the preset instability degree, and it is necessary to continue to control the rear wheels to cooperate to maintain vehicle stability; when the target steering is to the right, that is, the adhesion coefficient between the right wheels of the target vehicle and the current driving road surface is less than the adhesion coefficient between the left wheels and the current driving road surface, when the current steering wheel angle is negative, the preset steering wheel angle threshold is negative. If the current steering wheel angle is greater than the preset steering wheel angle threshold, then it is required that the increase in the current steering wheel angle compared to the previous control moment is not large. Therefore, both the current steering wheel angle change rate and the preset steering wheel angle change rate are positive. If the current steering wheel angle change rate is less than the preset steering wheel angle change rate, it is considered that the vehicle driving instability degree at the current control moment reaches the preset instability degree, and it is necessary to continue to control the rear wheels to cooperate to maintain vehicle stability.

[0096] As can be seen from the above technical solutions of the embodiments of the present application, the embodiments of the present application use the concrete parameter of the steering wheel angle to evaluate the instability degree of vehicle driving, so that the traction control system has a clearer judgment criterion for whether to control the rear wheels, and further introduces the parameter of the change rate of the steering wheel angle to set an offset for the judgment of the instability degree of vehicle driving, ensuring the robustness of the judgment.

[0097] S109. Determine the target angle of the rear wheels of the target vehicle at the current control moment based on the target steering and the base angle; the base angle is the angle of the rear wheels of the target vehicle at the previous control moment.

[0098] Wherein, the base angle is the rotation angle and rotation direction of the position of the rear wheels of the target vehicle at the previous control moment relative to the initial position of the rear wheels. In specific implementation, the rotation angle of the position of the rear wheels of the target vehicle at the previous control moment relative to the initial position of the rear wheels is the absolute value of the base angle, and the rotation direction of the position of the rear wheels of the target vehicle at the previous control moment relative to the initial position of the rear wheels is represented by the positive or negative of the base angle.

[0099] Wherein, the current control moment is the start moment of the current operation cycle of the traction control system.

[0100] Wherein, the target angle is the rotation angle and rotation direction of the target position for controlling the rear-wheel steering at the current control moment relative to the initial position of the rear wheels. In specific implementation, the rotation angle of the target position for controlling the rear-wheel steering at the current control moment relative to the initial position of the rear wheels is the absolute value of the target angle, and the rotation direction of the target position for controlling the rear-wheel steering at the current control moment relative to the initial position of the rear wheels is represented by the positive or negative of the target angle.

[0101] Wherein, the previous control moment is the start moment of the previous operation cycle of the traction control system.

[0102] Specifically, it is necessary to first calculate the change rate of the rear-wheel angle, and then combine the angle of the rear wheels of the target vehicle at the previous control moment to obtain the angle of the rear wheels of the target vehicle at the current control moment. When the current steering wheel steering is opposite to the target steering, a larger steering amplitude of the rear wheels is required to maintain vehicle stability. The current steering wheel angle changes dynamically, and the current steering wheel steering also changes dynamically. Therefore, the current steering wheel steering may not be opposite to the target steering, and there are also certain differences in the change rates of the rear-wheel angles corresponding to the two situations.

[0103] In an exemplary embodiment, as Figure 3 shown, it is a schematic flowchart of a method for determining the rear-wheel angle of a vehicle provided by the embodiments of the present application. The above step S109 may include:

[0104] S301. Determine the current braking control intervention torque based on the road surface type recognition result; obtain the basic change rate of the rear wheel angle corresponding to the current braking control intervention torque.

[0105] Among them, the road surface type recognition result includes the adhesion coefficients of the wheels on both sides of the target vehicle and the current driving road surface, based on which it can be determined whether the current driving road surface of the target vehicle is a low-adhesion road surface on the left side or a low-adhesion road surface on the right side.

[0106] Among them, the current braking control intervention torque is the braking torque exerted by the traction control system on the drive wheels of the target vehicle based on the road surface type recognition result at the current control moment. Specifically, when the current driving road surface of the target vehicle is a low-adhesion road surface on the left side, the traction control system brakes the left drive wheel; when the current driving road surface of the target vehicle is a low-adhesion road surface on the right side, the traction control system brakes the right drive wheel. In specific implementation, the above two situations can be distinguished by the positive and negative of the braking control intervention torque. For example, when the traction control system brakes the left drive wheel, the braking control intervention torque is negative; when the traction control system brakes the right drive wheel, the braking control intervention torque is positive.

[0107] Among them, the basic change rate of the rear wheel angle is a value corresponding to the current braking control intervention torque and serves as a basic quantity when calculating the change rate of the rear wheel angle. In specific implementation, given the curve data graph of the braking control intervention torque and the basic change rate of the rear wheel angle, the value of the basic change rate of the rear wheel angle can be obtained by looking up the table based on the current braking control intervention torque.

[0108] In an exemplary embodiment, as Figure 4 shown, it is a schematic flowchart of a method for judging the correctness of the basic change rate of the rear wheel angle provided by the embodiment of the present application. After the above step S301, the following steps may further be included:

[0109] S401. Judge whether the operation symbol of the basic change rate of the rear wheel angle is consistent with the operation symbol of the current braking control intervention torque.

[0110] Specifically, if the judgment result is yes, step S303 can be executed; conversely, if the judgment result is no, step S403 can be executed.

[0111] Among them, the operation symbol of the basic change rate of the rear wheel angle is related to the operation symbol of the current braking control intervention torque, as Figure 5As shown in the figure, it is a schematic flowchart of a method for calculating the change rate of the rear wheel angle provided by an embodiment of the present application. Among them, T_brake is the braking control intervention torque, and base_ramp is the basic change rate of the rear wheel angle. It can be seen from the curve graph of the braking control intervention torque and the basic change rate of the rear wheel angle that when the braking control intervention torque is positive, the basic change rate of the rear wheel angle is positive; when the braking control intervention torque is 0, the basic change rate of the rear wheel angle is 0; when the braking control intervention torque is negative, the basic change rate of the rear wheel angle is negative.

[0112] In specific implementation, the operation symbol of the basic change rate of the rear wheel angle is normally the same as that of the current braking control intervention torque, and the subsequent steps can be continued; if the operation symbol of the basic change rate of the rear wheel angle is inconsistent with that of the current braking control intervention torque, it indicates that the algorithm is incorrect, and the rear wheel is not steered at the current control moment, that is, the target angle is set to 0.

[0113] S403, determine that the target angle is zero.

[0114] Specifically, when the operation symbol of the basic change rate of the rear wheel angle is inconsistent with that of the current braking control intervention torque, the target angle at the current control moment is set to 0, and the rear wheel is not steered.

[0115] It can be seen from the above technical solutions of the embodiments of the present application that the embodiments of the present application verify the correctness of the operation symbol of the basic change rate of the rear wheel angle to prevent the situation of incorrect rear wheel steering control caused by incorrect look-up table, and improve the robustness of the algorithm.

[0116] S303, based on the opposite direction of the target steering, determine the reference steering of the current steering wheel; based on the current steering wheel angle, determine the current steering of the target vehicle's steering wheel.

[0117] Among them, the reference steering is a reference benchmark for judging which rear wheel angle change rate is applicable to the current steering of the steering wheel. Specifically, due to the dynamic change of the current steering wheel angle, there are two situations for the current steering of the steering wheel. One situation is that the current steering of the steering wheel is consistent with the reference steering, and the other situation is that the current steering of the steering wheel is inconsistent with the reference steering. When the current steering of the steering wheel is consistent with the reference steering, the rear wheel steering angle needs to be larger than that in the other situation to control the vehicle stability.

[0118] Among them, the current steering of the steering wheel is the rotation direction of the current position of the steering wheel of the target vehicle relative to the initial position of the steering wheel.

[0119] S305, judge whether the current steering of the steering wheel is consistent with the reference steering.

[0120] Specifically, if the judgment result is negative, step S307 can be executed; conversely, if the judgment result is positive, step S3011 can be executed.

[0121] In specific implementation, when the current steering wheel steering is inconsistent with the reference steering, the target angle can be calculated according to the methods of steps S307 to S309; when the current steering wheel steering is consistent with the reference steering, to control the vehicle stability, the steering angle of the rear wheels needs to be larger than that in the previous case. Therefore, according to the methods of steps S3011 to S3015, the change rate of the rear wheel angle is made larger than that calculated in the previous case, and thus the calculated target angle is also larger than the target angle calculated in the previous case.

[0122] S307. Determine a first change rate of the rear wheels of the target vehicle based on the current braking control intervention torque change rate, the current steering wheel angle change rate, the current yaw angle change rate, and the basic change rate of the rear wheel angle.

[0123] Among them, the current braking control intervention torque change rate is the change speed of the braking control intervention torque made by the traction control system at the current control moment. In specific implementation, the difference between the current braking control intervention torque and the braking control intervention torque at the previous control moment is divided by the operation period of the traction control system to obtain the current braking control intervention torque change rate.

[0124] Among them, the current steering wheel angle change rate is the change speed of the steering wheel angle of the target vehicle at the current control moment. In specific implementation, the difference between the current steering wheel angle and the steering wheel angle at the previous control moment is divided by the operation period of the traction control system to obtain the current steering wheel angle change rate.

[0125] Among them, the current yaw angle change rate is the change speed of the yaw angle of the target vehicle at the current control moment. In specific implementation, the difference between the yaw angle of the target vehicle at the current control moment and the yaw angle of the target vehicle at the previous control moment is divided by the operation period of the traction control system to obtain the current yaw angle change rate.

[0126] Among them, the first change rate is the increase or decrease of the rear wheel angle at the current control moment compared with the previous control moment. For example, when the target angle is positive and the target steering is to the right, if the operation symbol of the first change rate is positive, it means the rear wheel angle increases; if the operation symbol of the first change rate is negative, it means the rear wheel angle decreases. When the target angle is negative and the target steering is to the left, if the operation symbol of the first change rate is positive, it means the rear wheel angle decreases; if the operation symbol of the first change rate is negative, it means the rear wheel angle increases.

[0127] In an exemplary implementation manner, step S307 above may include the following steps:

[0128] Obtain a first weight corresponding to the current braking control intervention torque change rate, a second weight corresponding to the current steering wheel angle change rate, and a third weight corresponding to the current yaw angle change rate; the first weight is a positive value, the second weight is a negative value, and the third weight is a negative value;

[0129] Based on the current braking control intervention torque change rate and the first weight, the current steering wheel angle change rate and the second weight, and the current yaw angle change rate and the third weight, perform weighted summation to obtain the first angle change rate.

[0130] Among them, the first weight is a calibratable value for correcting the current braking control intervention torque change rate during the calculation of the first angle change rate, and the current braking control intervention torque change rate is a positive correlation factor for the traction control system to control vehicle stability. Therefore, the first weight is a positive value.

[0131] Among them, the second weight is a calibratable value for correcting the current steering wheel angle change rate during the calculation of the first angle change rate, and the current steering wheel angle change rate is a negative correlation factor for the traction control system to control vehicle stability. Therefore, the second weight is a negative value.

[0132] Among them, the third weight is a calibratable value for correcting the current yaw angle change rate during the calculation of the first angle change rate, and the current yaw angle change rate is a negative correlation factor for the traction control system to control vehicle stability. Therefore, the third weight is a negative value.

[0133] Among them, the first angle change rate is the increase or decrease of the target angle of the rear wheels at the current control moment compared with the previous control moment when the current steering wheel steering is inconsistent with the reference steering. In specific implementation, as Figure 5 shown, where T_brake_dot is the braking control intervention torque change rate, SAS_dot is the steering wheel angle change rate, Gain_1 is the weight of T_brake_dot; Gain_2 is the weight of SAS_dot; Gain_3 is the weight of the yaw angle change rate. The offset obtained by weighted summation is summed with the base ramp of the rear wheel angle basic change rate to obtain the first angle change rate Ramp_1.

[0134] It can be seen from the above technical solutions of the embodiments of the present application that according to the relevant situations of each relevant factor and the process of the traction control system controlling vehicle stability, the embodiments of the present application set corresponding weights to correct each relevant factor, and the calculated increase or decrease of the rear wheel angle is relatively accurate.

[0135] S309. Determine the target angle based on the base angle and the first angle change rate.

[0136] Among them, the basic corner is the rotation angle and rotation direction of the rear wheels of the target vehicle at the previous control moment compared with the initial position of the rear wheels. In specific implementation, the rotation angle of the rear wheels of the target vehicle at the previous control moment compared with the initial position of the rear wheels is the absolute value of the basic corner, and the rotation direction of the rear wheels of the target vehicle at the previous control moment compared with the initial position of the rear wheels is represented by the positive or negative of the basic corner.

[0137] Among them, the target corner is the rotation angle and rotation direction of the target position for controlling the rear-wheel steering at the current control moment compared with the initial position of the rear wheels. In specific implementation, the rotation angle of the target position for controlling the rear-wheel steering at the current control moment compared with the initial position of the rear wheels is the absolute value of the target corner, and the rotation direction of the target position for controlling the rear-wheel steering at the current control moment compared with the initial position of the rear wheels is represented by the positive or negative of the target corner. In specific implementation, by summing the basic corner and the first corner change rate, the target corner in the case where the current steering wheel steering is inconsistent with the reference steering can be obtained.

[0138] S3011, obtain the rear-wheel steering coefficient corresponding to the current steering wheel angle; the rear-wheel steering coefficient is greater than or equal to a preset value.

[0139] Among them, the rear-wheel steering coefficient is the weight value corresponding to the current steering wheel angle, and is used to correct the first corner change rate when the current steering wheel steering is consistent with the reference steering. In specific implementation, the curve data graph of the absolute value of the current steering wheel angle and the rear-wheel steering coefficient is known, such as Figure 5 shown, where SAS is the steering wheel angle and SAS_gain is the rear-wheel steering coefficient. Since SAS_gain is used to increase the absolute value of the first corner change rate when the current steering wheel steering is consistent with the reference steering, SAS_gain is greater than or equal to 1. By looking up the table based on the absolute value of the current steering wheel angle, the rear-wheel steering coefficient can be obtained.

[0140] S3013, multiply the first corner change rate and the rear-wheel steering coefficient to obtain a second corner change rate.

[0141] Among them, the second corner change rate is the increase or decrease amount of the target corner for controlling the rear wheels at the current control moment compared with the previous control moment when the current steering wheel steering is consistent with the reference steering. In specific implementation, as Figure 5 shown, where multiplying the first corner change rate Ramp_1 and the rear-wheel steering coefficient SAS_gain can obtain the second corner change rate Ramp_2.

[0142] S3015, determine the target corner based on the basic corner and the second corner change rate.

[0143] Specifically, by summing the basic steering angle and the change rate of the second steering angle, the target steering angle for controlling the rear-wheel steering can be obtained when the current steering of the steering wheel is consistent with the reference steering.

[0144] As can be seen from the above technical solutions of the embodiments of the present application, by comparing the current steering of the steering wheel with the target steering, calculating the target steering angle for controlling the rear-wheel steering in different cases, and controlling the rear-wheel steering in a targeted manner, while keeping the vehicle driving stably, the suppression of the vehicle acceleration performance is reduced.

[0145] S1011, based on the target steering angle, control the rear-wheel steering of the target vehicle for a preset duration.

[0146] Wherein, the preset duration is the duration for controlling the rear-wheel steering at the current control moment of the traction control system.

[0147] S1013, determine the steering of the rear wheels of the target vehicle at the previous control moment to obtain the basic steering.

[0148] Specifically, when the driving instability degree of the target vehicle does not reach the preset instability degree, it is necessary to further determine whether the rear-wheel steering control of the target vehicle at the previous control moment is the rear-wheel steering control required at the current control moment. When the basic steering is consistent with the target steering, the rear-wheel steering control at the previous control moment is the rear-wheel steering control required at the current control moment; when the basic steering is inconsistent with the target steering, the rear-wheel steering control at the previous control moment is the rear-wheel steering control not required at the current control moment.

[0149] S1015, determine whether the basic steering is consistent with the target steering.

[0150] Specifically, if the judgment result is yes, step S1019 can be executed; on the contrary, if the judgment result is no, step S1017 can be executed.

[0151] Specifically, when the basic steering is consistent with the target steering, the rear-wheel steering control at the previous control moment is the rear-wheel steering control required at the current control moment, and it is necessary to further determine whether the control at the previous control moment has ended to decide whether the current control moment needs to continue to execute the control at the previous control moment; when the basic steering is inconsistent with the target steering, the rear-wheel steering control at the previous control moment is the rear-wheel steering control not required at the current control moment, so there is no need to determine whether the control at the previous control moment has ended, and whether it has ended or not, the rear wheels of the current control moment do not steer.

[0152] S1017, control the rear wheels of the target vehicle not to steer.

[0153] In specific implementation, the traction control system sets the target steering angle to 0.

[0154] S1019. Determine the duration from the start time of the rear-wheel steering of the target vehicle at the previous control moment to the current control moment to obtain the steering duration.

[0155] Among them, the start time is the time when the rear-wheel steering control action at the previous control moment starts. Specifically, since the preset duration is usually longer than the operation period of the traction control system, the driving instability degree of the target vehicle at the previous control moment may not reach the preset instability degree. Therefore, the rear-wheel steering control at the previous control moment may not start from the previous control moment, and the start time is not the same as the previous control moment.

[0156] Among them, the steering duration is the duration of the rear-wheel steering control at the previous control moment. Specifically, since the rear-wheel steering control at the previous control moment may not start from the previous control moment, the steering duration is not necessarily the operation period of the traction control system and needs to be timed separately.

[0157] S1021. Judge whether the steering duration is less than or equal to the preset duration.

[0158] Specifically, if the judgment result is yes, step S109 can be executed; on the contrary, if the judgment result is no, step S1017 can be executed.

[0159] Specifically, when the basic steering is consistent with the target steering, the rear-wheel steering control at the previous control moment is the rear-wheel steering control required at the current control moment. If the steering duration is less than or equal to the preset duration, it indicates that the rear-wheel steering control at the previous control moment has not ended and needs to continue to be controlled; if the steering duration is greater than the preset duration, it indicates that the rear-wheel steering control at the previous control moment has ended and there is no need to continue to be controlled. Therefore, the rear wheels are not steered at the current control moment.

[0160] It can be seen from the above technical solutions of the embodiments of the present application that the embodiments of the present application calculate the instability degree of the vehicle on the split road surface through the traction control system, judge the rear-wheel steering based on the steering wheel steering and the identification of the left and right road surface adhesion coefficients, and then calculate the rear-wheel steering angle. By controlling the rear-wheel steering, the dynamic driving posture of the vehicle is changed, and the vehicle can be better controlled on the split road surface, so that the vehicle can maintain stability with less steering wheel intervention and improve the acceleration performance of the vehicle at the same time.

[0161] Corresponding to the vehicle rear-wheel steering control methods provided in the above several embodiments, an embodiment of the present application also provides a vehicle rear-wheel steering control device. Since the vehicle rear-wheel steering control device provided in the embodiment of the present application corresponds to the vehicle rear-wheel steering control methods provided in the above several embodiments, the implementation manners of the foregoing vehicle rear-wheel steering control methods are also applicable to the vehicle rear-wheel steering control device provided in this embodiment and will not be described in detail in this embodiment.

[0162] Please refer to Figure 6 , which shows a schematic structural diagram of a vehicle rear-wheel steering control device provided in an embodiment of the present application. The device has the function of implementing the vehicle rear-wheel steering control method in the above method embodiment. The function can be implemented by hardware or by hardware executing corresponding software. As Figure 6 shown, the device may include:

[0163] A road surface recognition module 610, configured to recognize the road surface type of the current driving road surface of the target vehicle in response to a traction control instruction, and obtain a road surface type recognition result;

[0164] A steering determination module 620, configured to determine a target steering based on the direction of the target side wheels of the target vehicle in the horizontal direction relative to the target vehicle when the road surface type recognition result indicates a target type road surface; the target type road surface refers to a road surface with inconsistent adhesion coefficients of the left and right wheels of the vehicle; the adhesion coefficient of the target side wheels to the current driving road surface is less than the adhesion coefficient of the other side wheels of the target vehicle to the current driving road surface;

[0165] A first stability judgment module 630, configured to judge whether the driving instability degree of the target vehicle reaches a preset instability degree based on the target steering and the current steering wheel angle;

[0166] A first corner determination module 640, configured to determine the target corner of the rear wheels of the target vehicle at the current control moment based on the target steering and a base corner when the driving instability degree reaches the preset instability degree; the base corner is the corner of the rear wheels of the target vehicle at the previous control moment;

[0167] A first rear-wheel control module 650, configured to control the rear-wheel steering of the target vehicle according to a preset duration based on the target corner.

[0168] In an exemplary implementation manner, the first stability judgment module includes:

[0169] A first steering wheel steering module, configured to determine the current steering of the target vehicle based on the current steering wheel angle;

[0170] A corner judgment module, configured to determine whether the absolute value of the current steering wheel angle is greater than or equal to a preset steering wheel angle threshold when the current steering wheel steering is inconsistent with the target steering;

[0171] A first instability determination module, configured to determine that the driving instability degree of the target vehicle reaches the preset instability degree when the absolute value of the current steering wheel angle is greater than or equal to the preset steering wheel angle threshold.

[0172] In an exemplary embodiment, the device further includes a second stability judgment module for judging whether the driving instability degree of the target vehicle reaches the preset instability degree based on the steering wheel angle change rate. The second stability judgment module includes:

[0173] A change rate acquisition module, configured to acquire the current steering wheel angle change rate when the absolute value of the current steering wheel angle is less than the preset steering wheel angle threshold;

[0174] A change rate judgment module, configured to judge whether the absolute value of the current steering wheel angle change rate is less than a preset steering wheel angle change rate threshold;

[0175] A second instability determination module, configured to determine that the driving instability degree of the target vehicle reaches the preset instability degree when the absolute value of the current steering wheel angle change rate is less than the preset steering wheel angle change rate threshold.

[0176] In an exemplary embodiment, the device further includes a steering judgment module for judging the rear-wheel steering at the previous control moment when the instability degree is not satisfied. The steering judgment module includes:

[0177] A basic steering module, configured to determine the steering of the rear wheels of the target vehicle at the previous control moment to obtain a basic steering when the driving instability degree does not reach the preset instability degree;

[0178] A second rear-wheel control module, configured to control the rear wheels of the target vehicle not to steer when the basic steering is inconsistent with the target steering.

[0179] In an exemplary embodiment, the device further includes a duration judgment module for judging whether the rear-wheel steering duration reaches a preset duration. The duration judgment module includes:

[0180] A steering duration module, configured to determine the duration from the start moment of the rear-wheel steering of the target vehicle at the previous control moment to the current control moment to obtain a steering duration when the basic steering is consistent with the target steering;

[0181] A second corner angle determination module, configured to determine a target corner angle of the rear wheels of the target vehicle at the current control moment based on the target steering and the basic corner angle when the steering duration is less than or equal to the preset duration;

[0182] A third rear-wheel control module, configured to control the rear-wheel steering of the target vehicle according to the preset duration based on the target corner angle.

[0183] In an exemplary embodiment, the device further includes a fourth rear-wheel control module configured to control the rear wheels not to steer when the rear-wheel steering duration reaches the preset duration. The fourth rear-wheel control module includes:

[0184] A fourth rear-wheel control module, configured to control the rear wheels of the target vehicle not to steer when the steering duration is greater than the preset duration.

[0185] In an exemplary embodiment, the first corner angle determination module or the second corner angle determination module includes:

[0186] A data acquisition module, configured to determine a current braking control intervention torque based on the road surface type recognition result; and acquire a basic change rate of the rear-wheel corner angle corresponding to the current braking control intervention torque;

[0187] A second steering wheel steering module, configured to determine a reference steering of the current steering wheel based on the opposite direction of the target steering; and determine the current steering of the target vehicle based on the current steering wheel corner angle;

[0188] A first corner angle change rate module, configured to determine a first corner angle change rate of the rear wheels of the target vehicle based on a current braking control intervention torque change rate, a current steering wheel corner angle change rate, a current yaw angle change rate, and the basic change rate of the rear-wheel corner angle when the current steering of the steering wheel is inconsistent with the reference steering;

[0189] A first target corner angle module, configured to determine the target corner angle based on the basic corner angle and the first corner angle change rate.

[0190] In an exemplary embodiment, the first corner angle change rate module includes:

[0191] A weight acquisition module, configured to acquire a first weight corresponding to the current braking control intervention torque change rate, a second weight corresponding to the current steering wheel corner angle change rate, and a third weight corresponding to the current yaw angle change rate; the first weight is a positive value, the second weight is a negative value, and the third weight is a negative value;

[0192] A weighted summation module, configured to perform weighted summation based on the current braking control intervention torque change rate, the first weight value, the current steering wheel angle change rate, the second weight value, the current yaw angle change rate, and the third weight value, to obtain the first angle change rate.

[0193] In an exemplary embodiment, the apparatus further includes a third angle determination module configured to calculate a target angle when the current steering wheel steering is consistent with a reference steering. The third angle determination module includes:

[0194] A coefficient acquisition module, configured to obtain a rear-wheel steering coefficient corresponding to the current steering wheel angle when the current steering wheel steering is consistent with the reference steering; the rear-wheel steering coefficient is greater than or equal to a preset value;

[0195] A second angle change rate module, configured to obtain a second angle change rate by multiplying the first angle change rate and the rear-wheel steering coefficient;

[0196] A second target angle module, configured to determine the target angle based on the base angle and the second angle change rate.

[0197] In an exemplary embodiment, the apparatus further includes a coefficient judgment module configured to judge whether the operation symbol of the rear-wheel steering coefficient is correct. The coefficient judgment module includes:

[0198] A coefficient judgment module, configured to determine that the target angle is zero when the operation symbol of the rear-wheel angle base change rate is inconsistent with the operation symbol of the current braking control intervention torque.

[0199] It should be noted that, when the apparatus provided in the above embodiments realizes its functions, only the division of the above functional modules is used for illustration. In practical applications, the above functions may be allocated to different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. In addition, the apparatus provided in the above embodiments and the method embodiments belong to the same concept, and the specific implementation process thereof can be found in the method embodiments, which will not be elaborated here.

[0200] An embodiment of the present application provides an electronic device, which includes a processor and a memory. At least one instruction or at least one program segment is stored in the memory, and the at least one instruction or the at least one program segment is loaded and executed by the processor to implement any one of the vehicle rear-wheel steering control methods provided in the above method embodiments.

[0201] The memory can be used to store software programs and modules. By running the software programs and modules stored in the memory, the processor can execute various functional applications and data processing. The memory mainly includes a program storage area and a data storage area. Among them, the program storage area can store the operating system, application programs required for functions, etc.; the data storage area can store data created according to the use of the device, etc. In addition, the memory can include high-speed random access memory and can also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other volatile solid-state storage devices. Accordingly, the memory can also include a memory controller to provide the processor with access to the memory.

[0202] The method embodiments provided in the embodiments of the present application can be executed on a computer terminal, a server, or a similar computing device, that is, the above-mentioned electronic device can include a computer terminal, a server, or a similar computing device. Figure 7 It is a hardware structure block diagram of a computer device for running a vehicle rear-wheel steering control method provided by an embodiment of the present invention. As Figure 7 shown, the internal structure of the computer device can include, but is not limited to: a processor, a network interface, and a memory. Among them, the processor, network interface, and memory in the computer device can be connected by a bus or other means. In the embodiments of this specification Figure 7 take the connection by bus as an example.

[0203] Among them, the processor (or CPU (Central Processing Unit, central processor)) is the computing core and control core of the computer device. The network interface can optionally include a standard wired interface, a wireless interface (such as WI-FI, mobile communication interface, etc.). The memory (Memory) is the memory device in the computer device, used to store programs and data. It can be understood that the memory here can be a high-speed RAM storage device or a non-volatile storage device, such as at least one magnetic disk storage device; optionally, it can also be at least one storage device located far from the aforementioned processor. The memory provides a storage space, and this storage space stores the operating system of the electronic device, which can include, but is not limited to: Windows system (an operating system), Linux (an operating system), Android (a mobile operating system) system, IOS (a mobile operating system) system, etc. The present invention does not make any limitations in this regard; and, one or more instructions suitable for being loaded and executed by the processor are also stored in this storage space, and these instructions can be one or more computer programs (including program codes). In the embodiments of this specification, the processor loads and executes one or more instructions stored in the memory to implement the vehicle rear-wheel steering control method provided by the above method embodiments.

[0204] An embodiment of the present application further provides a computer-readable storage medium, which can be disposed in an electronic device to store at least one instruction or at least one program related to implementing a vehicle rear-wheel steering control method. The at least one instruction or the at least one program is loaded and executed by the processor to implement any vehicle rear-wheel steering control method provided in the above method embodiments.

[0205] Optionally, in this embodiment, the above storage medium may include, but is not limited to: various media such as USB flash drives, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), mobile hard disks, magnetic disks, or optical discs that can store program codes.

[0206] It should be noted that: the above sequence of embodiments of the present application is only for description and does not represent the superiority or inferiority of the embodiments. And the above specific embodiments of this specification have been described. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be executed in a different order than in the embodiments and still achieve the desired result. Additionally, the processes depicted in the drawings do not necessarily require the specific order or sequential order shown to achieve the desired result. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0207] Each embodiment in this specification is described in a progressive manner. The same or similar parts among the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiments.

[0208] Those of ordinary skill in the art can understand that all or part of the steps for implementing the above embodiments can be completed by hardware, or can be completed by a program instructing relevant hardware. The program can be stored in a computer-readable storage medium, and the above-mentioned storage medium can be a read-only memory, a magnetic disk, or an optical disc, etc.

[0209] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for controlling the rear-wheel steering of a vehicle, characterized in that, The method includes: In response to a traction control instruction, identifying the road surface type of the current driving road surface of the target vehicle to obtain a road surface type identification result; When the road surface type identification result indicates a target type road surface, determining a target steering based on the direction of the target side wheels of the target vehicle in the horizontal direction relative to the target vehicle; the target type road surface refers to a road surface with inconsistent adhesion coefficients between the left and right wheels of the vehicle; the adhesion coefficient of the target side wheels to the current driving road surface is less than the adhesion coefficient of the other side wheels of the target vehicle to the current driving road surface; Based on the target steering and the current steering wheel angle, determining whether the driving instability degree of the target vehicle reaches a preset instability degree; When the driving instability degree reaches the preset instability degree, determining the target angle of the rear wheels of the target vehicle at the current control moment based on the target steering and the base angle; the base angle is the angle of the rear wheels of the target vehicle at the previous control moment; Based on the target angle, controlling the rear wheels of the target vehicle to steer according to a preset duration; Among them, the determining whether the driving instability degree of the target vehicle reaches the preset instability degree based on the target steering and the current steering wheel angle includes: determining the current steering of the target vehicle based on the current steering wheel angle; when the current steering is inconsistent with the target steering, determining whether the absolute value of the current steering wheel angle is greater than or equal to a preset steering wheel angle threshold; when the absolute value of the current steering wheel angle is greater than or equal to the preset steering wheel angle threshold, determining that the driving instability degree of the target vehicle reaches the preset instability degree.

2. The vehicle rear-wheel steering control method according to claim 1, wherein The method further includes: When the absolute value of the current steering wheel angle is less than the preset steering wheel angle threshold, obtaining the current steering wheel angle change rate; Determining whether the absolute value of the current steering wheel angle change rate is less than a preset steering wheel angle change rate threshold; When the absolute value of the current steering wheel angle change rate is less than the preset steering wheel angle change rate threshold, determining that the driving instability degree of the target vehicle reaches the preset instability degree.

3. The vehicle rear-wheel steering control method according to claim 1, characterized in that The method further includes: When the driving instability degree does not reach the preset instability degree, determining the steering of the rear wheels of the target vehicle at the previous control moment to obtain a base steering; When the base steering is inconsistent with the target steering, controlling the rear wheels of the target vehicle not to steer.

4. The vehicle rear-wheel steering control method according to claim 3, wherein The method further includes: When the base steering is consistent with the target steering, determining the duration from the start moment of the rear wheel steering of the target vehicle at the previous control moment to the current control moment to obtain a steering duration; When the steering duration is less than or equal to the preset duration, determining the target angle of the rear wheels of the target vehicle at the current control moment based on the target steering and the base angle; Based on the target angle, controlling the rear wheels of the target vehicle to steer according to the preset duration.

5. The vehicle rear-wheel steering control method according to claim 4, wherein The method further includes: When the steering duration is greater than the preset duration, controlling the rear wheels of the target vehicle not to steer.

6. The vehicle rear wheel steering control method according to claim 1 or 4, characterized in that, Determining a target angle of the rear wheels of the target vehicle at the current control moment based on the target steering and the basic angle includes: Determining a current braking control intervention torque based on the road surface type recognition result; obtaining a basic change rate of the rear wheel angle corresponding to the current braking control intervention torque; Determining a reference steering of the current steering wheel based on the opposite direction of the target steering; determining the current steering of the target vehicle based on the current steering wheel angle; When the current steering of the steering wheel is inconsistent with the reference steering, determining a first change rate of the rear wheel angle of the target vehicle based on the current braking control intervention torque change rate, the current steering wheel angle change rate, the current yaw angle change rate, and the basic change rate of the rear wheel angle; Determining the target angle based on the basic angle and the first change rate of the angle; 7. The vehicle rear wheel steering control method according to claim 6, wherein The determining the first change rate of the rear wheel angle of the target vehicle based on the current braking control intervention torque change rate, the current steering wheel angle change rate, the current yaw angle change rate, and the basic change rate of the rear wheel angle includes: Obtaining a first weight value corresponding to the current braking control intervention torque change rate, a second weight value corresponding to the current steering wheel angle change rate, and a third weight value corresponding to the current yaw angle change rate; the first weight value is a positive value, the second weight value is a negative value, and the third weight value is a negative value; Performing weighted summation based on the current braking control intervention torque change rate and the first weight value, the current steering wheel angle change rate and the second weight value, the current yaw angle change rate and the third weight value, to obtain the first change rate of the angle; 8. The vehicle rear-wheel steering control method according to claim 6, characterized in that The method further includes: When the current steering of the steering wheel is consistent with the reference steering, obtaining a rear wheel steering coefficient corresponding to the current steering wheel angle; the rear wheel steering coefficient is greater than or equal to a preset value; Multiplying the first change rate of the angle and the rear wheel steering coefficient to obtain a second change rate of the angle; Determining the target angle based on the basic angle and the second change rate of the angle; 9. The vehicle rear-wheel steering control method according to claim 8, wherein, After obtaining the basic change rate of the rear wheel angle corresponding to the current braking control intervention torque, the method further includes: When the operation symbol of the basic change rate of the rear wheel angle is inconsistent with the operation symbol of the current braking control intervention torque, determining that the target angle is zero; 10. A vehicle rear-wheel steering control device, characterized in that, The device includes: A road surface recognition module, configured to recognize the road surface type of the current driving road surface of the target vehicle in response to a traction control instruction, to obtain a road surface type recognition result; A steering determination module, configured to determine a target steering based on the direction of the target side wheels of the target vehicle in the horizontal direction relative to the target vehicle when the road surface type recognition result indicates a target type road surface; the target type road surface refers to a road surface with inconsistent adhesion coefficients between the left and right wheels of the vehicle; the adhesion coefficient of the target side wheels to the current driving road surface is less than the adhesion coefficient of the other side wheels of the target vehicle to the current driving road surface; The first stability judgment module is used to judge whether the driving instability degree of the target vehicle reaches a preset instability degree based on the target steering and the current steering wheel angle; The first angle determination module is used to determine the target angle of the rear wheels of the target vehicle at the current control moment based on the target steering and the basic angle when the driving instability degree reaches the preset instability degree; the basic angle is the angle of the rear wheels of the target vehicle at the previous control moment; The first rear wheel control module is used to control the rear wheel steering of the target vehicle according to a preset duration based on the target angle; Wherein, the first stability judgment module includes: a first steering wheel steering module for determining the current steering of the target vehicle based on the current steering wheel angle; an angle judgment module for judging whether the absolute value of the current steering wheel angle is greater than or equal to a preset steering wheel angle threshold when the current steering of the steering wheel is inconsistent with the target steering; a first instability determination module for determining that the driving instability degree of the target vehicle reaches the preset instability degree when the absolute value of the current steering wheel angle is greater than or equal to the preset steering wheel angle threshold.

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