Method and device for controlling wheel rotation angle

Abstract

The application discloses a wheel rotation angle control method and device. The method comprises the following steps: acquiring first wheel speed information of a front wheel of a vehicle and second wheel speed information of a rear wheel of the vehicle; predicting a front wheel expected rotation angle of the vehicle based on the first wheel speed information and the second wheel speed information; determining a rear wheel expected rotation angle of the vehicle based on the front wheel expected rotation angle; adjusting the rear wheel expected rotation angle based on a current moving posture of the vehicle, and controlling the rear wheel rotation angle of the vehicle through the adjusted rear wheel expected rotation angle. In this way, the front wheel expected rotation angle is predicted by introducing the front wheel speed information and the rear wheel speed information, so that the rotation angle of the rear wheel of the vehicle can be accurately determined when the steering wheel sensor fails or has low precision, and the technical problem that the rotation angle of the rear wheel cannot be accurately controlled when the steering wheel sensor fails or has low precision in the prior art is solved.

Description

Technical Field

[0001] This application relates to the field of vehicle control technology, specifically to a method and device for controlling wheel rotation angle. Background Technology

[0002] As vehicle wheelbase increases, so does turning radius, affecting vehicle agility in complex urban road conditions. To address this issue, rear-wheel steering systems have been introduced. By controlling the coordinated steering of the rear and front wheels, it achieves reverse steering at low speeds to reduce the turning radius and unidirectional steering at high speeds to improve stability. Related technologies typically collect the front wheel angles in real time and then determine the rear wheel angles based on these angles, thereby improving vehicle handling and stability. However, this method relies on steering wheel sensors to collect front wheel angles; if the steering wheel sensors fail or have low accuracy, it cannot accurately control the rear wheel angles. Summary of the Invention

[0003] In view of this, the embodiments of this application provide at least one method and apparatus for controlling wheel rotation angle.

[0004] The technical solution of this application embodiment is implemented as follows:

[0005] In a first aspect, embodiments of this application provide a method for controlling the wheel rotation angle, the method comprising:

[0006] Obtain the first wheel speed information of the front wheels of the vehicle and the second wheel speed information of the rear wheels of the vehicle;

[0007] Based on the first wheel speed information and the second wheel speed information, predict the expected steering angle of the vehicle's front wheels;

[0008] Based on the desired front wheel steering angle, the desired rear wheel steering angle of the vehicle is determined;

[0009] The desired rear wheel steering angle is adjusted based on the vehicle's current moving posture, and the rear wheel steering angle of the vehicle is controlled by the adjusted desired rear wheel steering angle.

[0010] In this embodiment, the wheel speed information of the front and rear wheels of the vehicle is first acquired to predict the desired steering angle of the front wheels, and then the desired steering angle of the rear wheels is determined by combining the desired steering angle of the front wheels. Subsequently, the desired steering angle of the rear wheels is dynamically adjusted according to the current movement posture of the vehicle, thereby controlling the steering angle of the rear wheels more accurately. In this way, on the one hand, by introducing the wheel speed information of the front and rear wheels to predict the desired steering angle of the front wheels, the steering angle of the rear wheels of the vehicle can be accurately determined even when the steering wheel sensor fails or has low accuracy, solving the technical problem in related technologies that it is impossible to accurately control the steering angle of the rear wheels when the steering wheel sensor fails or has low accuracy; on the other hand, by adjusting the desired steering angle of the rear wheels in combination with the real-time movement posture of the vehicle, the control strategy is more adapted to actual driving conditions, thereby improving the responsiveness and handling stability of the vehicle.

[0011] In some embodiments, predicting the desired front wheel steering angle of the vehicle based on the first wheel speed information and the second wheel speed information includes: determining the wheel speed difference between the two front wheels of the vehicle based on the first wheel speed information; determining the average rear wheel speed of the two rear wheels of the vehicle based on the second wheel speed information; determining a first ratio between the wheel speed difference between the two front wheels of the vehicle and the average rear wheel speed of the two rear wheels of the vehicle; determining a second ratio between the wheelbase of the vehicle and the track width of the vehicle; and determining the desired front wheel steering angle of the vehicle based on the first ratio and the second ratio.

[0012] In this embodiment, the desired front wheel steering angle of the vehicle is predicted based on a first ratio between the wheel speed difference between the two front wheels and the average rear wheel speed, and a second ratio between the wheelbase and track width. This provides a more comprehensive reflection of the vehicle's motion state and geometric characteristics, improving the accuracy of front wheel steering angle prediction and thus optimizing steering response and handling performance, enhancing the driving experience. Furthermore, the method provided in this embodiment can predict the desired front wheel steering angle even when the steering wheel sensor fails or has low accuracy, thereby improving vehicle control stability.

[0013] In some embodiments, determining the desired rear wheel steering angle of the vehicle based on the desired front wheel steering angle includes: determining the ratio coefficients of the front and rear wheels of the vehicle in a preset mapping table based on the current vehicle speed; the preset mapping table includes the correspondence between different vehicle speeds and different ratio coefficients of the front and rear wheels; and determining the desired rear wheel steering angle of the vehicle based on the desired front wheel steering angle and the ratio coefficients of the front and rear wheels of the vehicle.

[0014] In this embodiment, a pre-defined mapping table is used to establish the correspondence between vehicle speed and the front-to-rear wheel ratio coefficients. This allows for the automatic matching of appropriate ratio coefficients at different vehicle speeds, thus more reasonably determining the desired rear wheel steering angle. This avoids the inflexible control issues associated with fixed ratios and enhances the vehicle's adaptability to different speed ranges, thereby improving the overall comfort and stability of steering control.

[0015] In some embodiments, adjusting the desired rear wheel steering angle based on the vehicle's current moving posture and controlling the vehicle's rear wheel steering angle through the adjusted desired rear wheel steering angle includes: determining the vehicle's current moving posture based on the vehicle's steering information and the vehicle's acceleration information; and, if the current moving posture is a preset moving posture, adjusting the desired rear wheel steering angle based on the vehicle's front wheel steering and controlling the vehicle's rear wheel steering angle through the adjusted desired rear wheel steering angle.

[0016] In this embodiment, the current driving posture is determined by comprehensively considering the vehicle's steering and acceleration information, and the desired rear wheel steering angle is adjusted accordingly, making the rear wheel control logic more aligned with actual driving scenarios. This improves the vehicle's adaptability to complex road conditions and enhances its handling performance under specific operating conditions through targeted posture recognition and response mechanisms.

[0017] In some embodiments, adjusting the desired rear wheel steering angle based on the front wheel steering when the current moving posture is a preset moving posture includes: when the preset moving posture is a constant speed turning state, adjusting the direction of the desired rear wheel steering angle so that the direction of the desired rear wheel steering angle is the same as the front wheel steering angle.

[0018] In this embodiment, the front wheel steering is determined as the rear wheel steering, and the rear wheels are controlled to deflect towards the front wheel steering at an angle equal to the desired rear wheel steering angle. Thus, by aligning the desired rear wheel steering angle with the front wheel steering during a constant-speed turn, lateral slippage during cornering can be reduced, thereby improving vehicle stability and enhancing the comfort of the driver and passengers.

[0019] In some embodiments, the step of adjusting the desired rear wheel steering angle based on the front wheel steering of the vehicle when the current moving posture is a preset moving posture, and controlling the rear wheel steering angle of the vehicle through the adjusted desired rear wheel steering angle, includes: when the preset moving posture is an acceleration turning state and the current vehicle speed is greater than a first speed threshold, controlling the rear wheels of the vehicle to return to center; when the current vehicle speed is greater than a second speed threshold, adjusting the desired rear wheel steering angle based on the front wheel steering of the vehicle; wherein, the second speed threshold is greater than the first speed threshold; controlling the rear wheel steering angle of the vehicle through the adjusted desired rear wheel steering angle so that the front and rear wheels of the vehicle steer in the same direction.

[0020] In this embodiment, by setting multiple speed thresholds and combining them with the vehicle's motion state, the desired rear wheel steering angle is controlled in stages, effectively addressing dynamic changes during acceleration and cornering. This ensures, on the one hand, that the rear wheels travel in the same direction as the front wheels at high speeds, improving driving stability; on the other hand, it gradually transitions back to center within the low-to-medium speed range, reducing discomfort caused by sudden steering changes.

[0021] In some embodiments, adjusting the desired rear wheel angle based on the front wheel steering of the vehicle when the current moving posture is a preset moving posture, and controlling the rear wheel angle of the vehicle through the adjusted desired rear wheel angle, includes: when the vehicle is in a deceleration turning state, and the current speed of the vehicle is less than a second speed threshold and greater than a first speed threshold, controlling the rear wheels of the vehicle to return to center; when the current speed is less than the first speed threshold, adjusting the desired rear wheel angle based on the front wheel steering of the vehicle; and controlling the rear wheel angle of the vehicle through the adjusted desired rear wheel angle, so that the front and rear wheels of the vehicle steer in opposite directions.

[0022] In this embodiment, when the vehicle is decelerating and changing lanes, and the vehicle's current speed is less than a second speed threshold but greater than a first speed threshold, the rear wheels are controlled to return to center. When the current speed is less than the first speed threshold, the rear wheel steering angle is controlled by adjusting the desired rear wheel steering angle, so that the front and rear wheels steer in opposite directions. This achieves two benefits: firstly, maintaining rear wheel centering within a medium speed range helps maintain vehicle stability; secondly, allowing the front and rear wheels to deflect in opposite directions at low speeds enhances steering agility.

[0023] In some embodiments, the step of adjusting the desired rear wheel angle based on the front wheel steering of the vehicle when the current moving posture is a preset moving posture, and controlling the rear wheel angle of the vehicle through the adjusted desired rear wheel angle, includes: when the vehicle is in a stable state and the current vehicle speed is less than a first speed threshold, adjusting the desired rear wheel angle based on the front wheel steering of the vehicle; controlling the rear wheel angle of the vehicle through the adjusted desired rear wheel angle so that the front and rear wheels of the vehicle steer in opposite directions; when the current vehicle speed is greater than a second speed threshold, adjusting the desired rear wheel angle based on the front wheel steering of the vehicle; controlling the rear wheel angle of the vehicle through the adjusted desired rear wheel angle so that the front and rear wheels of the vehicle steer in the same direction.

[0024] In this embodiment, when the vehicle is in a stable state and its current speed is less than a first speed threshold, the rear wheel steering angle is controlled by adjusting the desired rear wheel steering angle, causing the front and rear wheels to steer in opposite directions. When the current speed is greater than a second speed threshold, the rear wheel steering angle is controlled by adjusting the desired rear wheel steering angle, causing the front and rear wheels to steer in the same direction. Thus, on the one hand, opposing wheel deflections improve steering sensitivity in low-speed steady-state conditions; on the other hand, unidirectional deflections enhance driving stability in high-speed steady-state conditions.

[0025] In some embodiments, when the vehicle is in a stable state, the method further includes: maintaining the opposite steering of the front and rear wheels of the vehicle during the process of the vehicle accelerating from the first speed threshold to the second speed threshold; and maintaining the same steering of the front and rear wheels of the vehicle during the process of the vehicle decelerating from the second speed threshold to the first speed threshold.

[0026] In this embodiment, during the process of a vehicle accelerating from a first speed threshold to a second speed threshold while in a stable state, the front and rear wheels maintain opposite steering directions; conversely, during the process of a vehicle decelerating from the second speed threshold to the first speed threshold while in a stable state, the front and rear wheels maintain the same steering direction. By maintaining the consistency or oppositeity of the steering directions of the front and rear wheels during speed changes, frequent switching of steering control is reduced, thereby improving the driving experience.

[0027] Secondly, embodiments of this application provide a wheel angle control device, the wheel angle control device comprising:

[0028] The acquisition module is used to acquire the first wheel speed information of the front wheels of the vehicle and the second wheel speed information of the rear wheels of the vehicle;

[0029] The prediction module is used to predict the desired steering angle of the front wheels of the vehicle based on the first wheel speed information and the second wheel speed information.

[0030] A determining module is used to determine the desired steering angle of the rear wheels of the vehicle based on the desired steering angle of the front wheels;

[0031] The control module is used to adjust the desired rear wheel steering angle based on the current moving posture of the vehicle, and to control the rear wheel steering angle of the vehicle through the adjusted desired rear wheel steering angle.

[0032] Thirdly, embodiments of this application provide a wheel steering angle control device, including a memory and a processor. The memory stores a computer program that can run on the processor, and the processor executes the program to implement some or all of the steps in the above method.

[0033] Fourthly, embodiments of this application provide a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements some or all of the steps in the above-described method.

[0034] Fifthly, embodiments of this application provide a computer program product, including a computer program or instructions, which, when executed by a processor, implement some or all of the steps in the above-described method.

[0035] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory, and are not intended to limit the technical solutions of this application. Attached Figure Description

[0036] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with this application and, together with the specification, serve to explain the technical solutions of this application.

[0037] Figure 1 A schematic diagram of the implementation process of a wheel steering angle control method provided in this application embodiment. Figure 1 ;

[0038] Figure 2 A schematic diagram of the implementation process of a wheel steering angle control method provided in this application embodiment. Figure 2 ;

[0039] Figure 3 A schematic diagram of the implementation process of a wheel steering angle control method provided in this application embodiment. Figure 3 ;

[0040] Figure 4 This is a schematic diagram of the composition structure of a wheel steering angle control device provided in an embodiment of this application;

[0041] Figure 5This is a schematic diagram of a hardware entity of a wheel steering angle control device provided in an embodiment of this application. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application are further described in detail below with reference to the accompanying drawings and embodiments. The described embodiments should not be regarded as limitations on this application. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0043] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0044] The terms “first / second / third” used here are merely to distinguish similar vehicles and do not represent a specific order of vehicles. It is understood that “first / second / third” may be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in a sequence other than that illustrated or described herein.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. The terminology used herein is for descriptive purposes only and is not intended to be limiting of this application.

[0046] To address the technical problem of inaccurate control of the rear wheel steering angle in related technologies, this application provides a wheel steering angle control method that can be applied to wheel steering angle control devices in vehicles, such as... Figure 1 As shown, the method includes the following steps S101 to S104:

[0047] Step S101: Obtain the first wheel speed information of the front wheels of the vehicle and the second wheel speed information of the rear wheels of the vehicle.

[0048] Here, the first wheel speed information refers to the rotational speed of the vehicle's front wheels per unit time, which is usually collected by wheel speed sensors mounted on the front wheels; the second wheel speed information refers to the rotational speed of the vehicle's rear wheels per unit time, also collected by wheel speed sensors mounted on the rear wheels. The first and second wheel speed information not only reflect the actual operating state of the wheels, but also help determine whether the vehicle is in abnormal driving conditions such as slippage or sideslip, and provide more accurate basic data for subsequent prediction of the desired front wheel steering angle.

[0049] For example, when turning at low speed on urban roads, there may be a significant difference between the first wheel speed information of the front wheels and the second wheel speed information of the rear wheels. This phenomenon indicates that the vehicle is undergoing a large steering action, and the control system needs to adopt a more refined front wheel desired steering angle control strategy. However, when driving at a constant speed in a straight line on a highway, the first wheel speed information of the front wheels and the second wheel speed information of the rear wheels are basically the same. This phenomenon indicates that the vehicle is in a stable state, and the control system has a lower need to adjust the rear wheel desired steering angle.

[0050] Step S102: Based on the first wheel speed information and the second wheel speed information, predict the expected steering angle of the front wheels of the vehicle.

[0051] Here, the desired front wheel steering angle refers to the ideal front wheel steering angle value calculated based on the vehicle's wheel speed information, which is used to guide the vehicle's actual steering actions.

[0052] In this embodiment of the application, the first wheel speed information includes the first sub-wheel speed information of the first wheel located at the left front of the vehicle and the second sub-wheel speed information of the second wheel located at the right front of the vehicle. At the same time, the second wheel speed information includes the third sub-wheel speed information of the third wheel located at the left rear of the vehicle and the fourth sub-wheel speed information of the fourth wheel located at the right rear of the vehicle. Then, the desired steering angle of the front wheels of the vehicle is predicted by using the first sub-wheel speed information, the second sub-wheel speed information, the third sub-wheel speed information and the fourth sub-wheel speed information.

[0053] It is understandable that the wheel speeds of different wheels of a vehicle differ when turning and when driving straight. Therefore, it is necessary to predict the desired steering angle of the front wheels of the vehicle in real time by using the wheel speeds of the different wheels.

[0054] In some embodiments, a mapping table of vehicle wheel speed and front wheel steering angle can be pre-constructed, which includes the correspondence between different vehicle wheel speeds and different front wheel steering angles. Then, during implementation, after collecting the vehicle's wheel speed information, the desired front wheel steering angle of the vehicle can be determined based on the vehicle's wheel speed information in different correspondences.

[0055] Step S103: Based on the desired front wheel steering angle, determine the desired rear wheel steering angle of the vehicle.

[0056] In this embodiment, a preset adjustment factor can be obtained, and then the desired rear wheel steering angle of the vehicle can be determined based on the adjustment factor and the desired front wheel steering angle. The adjustment factor can be a fixed parameter. In some embodiments, the adjustment factor is a dynamically changing parameter, for example, the adjustment factor can change with vehicle speed. Therefore, the current vehicle speed can be obtained first, and then, based on multiple mapping relationships between different vehicle speeds and different adjustment factors, the adjustment factor corresponding to the current vehicle speed can be determined.

[0057] Step S104: Adjust the desired rear wheel steering angle based on the current moving posture of the vehicle, and control the rear wheel steering angle of the vehicle through the adjusted desired rear wheel steering angle.

[0058] Here, the current movement posture refers to the overall motion state of the vehicle at a certain moment. For example, this current movement posture may indicate whether the vehicle is turning, accelerating, or decelerating.

[0059] In this embodiment, the vehicle's current movement posture can be determined first based on the vehicle's acceleration and steering information. Then, the desired rear wheel steering angle is adjusted based on the vehicle's current movement posture, and the rear wheel steering angle is controlled by the adjusted desired rear wheel steering angle. Adjusting the desired rear wheel steering angle refers to determining the steering direction of the vehicle's rear wheels; that is, the adjusted desired rear wheel steering angle is a steering angle value. It is understood that the desired rear wheel steering angle determined based on the desired front wheel steering angle is an angle value without direction, so the steering direction of the vehicle's rear wheels needs to be determined in real time based on the vehicle's current movement posture. For example, if the desired rear wheel steering angle is 'a', after adjusting 'a' based on the current movement posture, it becomes -a (representing the rear wheels turning a° to the right) or +a (representing the rear wheels turning a° to the left).

[0060] In some embodiments, the desired rear wheel steering angle can also be adjusted based on the vehicle's current moving posture. For example, when the vehicle's current moving posture is a rapid acceleration turn (large turning angle), the rear wheels may slip easily due to the rapid transfer of the vehicle's center of gravity. Therefore, it is necessary to appropriately reduce the desired rear wheel steering angle to avoid oversteering. On the other hand, when the vehicle is rapidly decelerating and changing lanes (small turning angle), the desired rear wheel steering angle needs to be increased due to the vehicle's strong inertia to improve steering response speed and stability.

[0061] In this embodiment, the wheel speed information of the front and rear wheels of the vehicle is first acquired to predict the desired steering angle of the front wheels, and then the desired steering angle of the rear wheels is determined by combining the desired steering angle of the front wheels. Subsequently, the desired steering angle of the rear wheels is dynamically adjusted according to the current movement posture of the vehicle, thereby controlling the steering angle of the rear wheels more accurately. In this way, on the one hand, by introducing the wheel speed information of the front and rear wheels to predict the desired steering angle of the front wheels, the steering angle of the rear wheels of the vehicle can be accurately determined even when the steering wheel sensor fails or has low accuracy, solving the technical problem in related technologies that it is impossible to accurately control the steering angle of the rear wheels when the steering wheel sensor fails or has low accuracy; on the other hand, by adjusting the desired steering angle of the rear wheels in combination with the real-time movement posture of the vehicle, the control strategy is more adapted to actual driving conditions, thereby improving the responsiveness and handling stability of the vehicle.

[0062] In some embodiments, such as Figure 2As shown, step S102 can be implemented by steps S201 to S205:

[0063] Step S201: Based on the first wheel speed information, determine the wheel speed difference between the two front wheels of the vehicle.

[0064] Here, wheel speed difference refers to the difference in linear velocity between the left and right front wheels of a vehicle. Wheel speed difference is usually caused by factors such as steering wheel angle, vehicle speed, and road conditions. By calculating wheel speed difference, the current steering state of the vehicle and the force on the tires can be reflected. For example, during a turn, the speed of the outer front wheel will be higher than that of the inner front wheel, forming a positive wheel speed difference; while in some complex road conditions (such as slippage), a reverse wheel speed difference may occur.

[0065] In this embodiment of the application, the first wheel speed information includes the first sub-wheel speed information of the first wheel located at the left front of the vehicle and the second sub-wheel speed information of the second wheel located at the right front of the vehicle. The difference between the first sub-wheel speed information and the second sub-wheel speed information can be determined as the wheel speed difference between the two front wheels of the vehicle.

[0066] Step S202: Based on the second wheel speed information, determine the average rear wheel speed of the two rear wheels of the vehicle.

[0067] Here, the average rear wheel speed of the two rear wheels of the vehicle refers to the average of the linear velocities of the left and right rear wheels of the vehicle. This average rear wheel speed is used to characterize the overall driving speed of the vehicle.

[0068] In this embodiment of the application, the second wheel speed information includes the third sub-wheel speed information of the third wheel located at the left rear of the vehicle and the fourth sub-wheel speed information of the fourth wheel located at the right rear of the vehicle. The average wheel speed of the third sub-wheel speed information and the fourth sub-wheel speed information can be determined as the average rear wheel speed of the two rear wheels of the vehicle.

[0069] Step S203: Determine a first ratio between the wheel speed difference between the two front wheels of the vehicle and the average rear wheel speed of the two rear wheels of the vehicle.

[0070] Here, the first ratio is a dimensionless parameter obtained by dividing the difference in wheel speed between the two front wheels of a vehicle by the average rear wheel speed of the two rear wheels. This first ratio reflects the relative relationship between the motion states of the front and rear wheels of the vehicle. For example, during a low-speed sharp turn, the difference in wheel speed between the two front wheels is large, while the average rear wheel speed is small, thus increasing the first ratio; while during high-speed straight travel, the difference in wheel speed between the two front wheels approaches zero, therefore the first ratio also approaches zero.

[0071] Step S204: Determine a second ratio between the wheelbase of the vehicle and the track width of the vehicle.

[0072] Here, the wheelbase is the distance between the front and rear axles of a vehicle, and the track width is the distance between the left and right wheels on the same axle. The second ratio, obtained by dividing the wheelbase by the track width, reflects the basic characteristics of the vehicle's geometry. Different vehicle models have different wheelbases and track widths.

[0073] Step S205: Based on the first ratio and the second ratio, determine the desired steering angle of the front wheels of the vehicle.

[0074] Here, the desired front wheel steering angle of the vehicle is a target steering angle calculated based on a combination of the first ratio and the second ratio. By combining the vehicle's dynamic state (first ratio) and geometry (second ratio), the front wheel steering angle suitable for the current driving scenario can be predicted more accurately.

[0075] In this embodiment of the application, the desired steering angle of the vehicle's front wheels can be achieved using formula (1):

[0076]

[0077] The derivation process of the above formula (1) is described below:

[0078] First, the simplified formula for the Ackermann bicycle model is formula (2):

[0079]

[0080] Where δ is the front wheel steering angle of the vehicle, L is the vehicle wheelbase, ω is the angular velocity of the vehicle about the center of rotation, and v is the vehicle speed. This formula describes the front wheel steering angle required to maintain the angular velocity ω when the vehicle is traveling at a speed v.

[0081] Second, when the vehicle is making a left turn, the turning radius of the left front wheel is as shown in formula (3), and the turning radius of the right front wheel is as shown in formula (4):

[0082]

[0083] Among them, R L R is the turning radius of the left front wheel. R R is the turning radius of the right front wheel, R is the turning radius of the vehicle's center of gravity, and W is the track width.

[0084] Third, the relationship between the wheel speed of the left front wheel and the turning radius is shown in formula (5), and the relationship between the wheel speed of the right front wheel and the turning radius is shown in formula (6):

[0085] v L =ω*R L Formula (5);

[0086] v R=ω*R R Formula (6);

[0087] Among them, V L V is the wheel speed of the left front wheel. R This is the wheel speed of the right front wheel.

[0088] Formula (7) is obtained from formulas (3) to (6):

[0089]

[0090] Fourth, substituting formula (7) into formula (2) yields formula (8):

[0091]

[0092] In formula (2), v equals (V L +V R ) / 2.

[0093] Fifth, according to Taylor's formula, arctanX≈X, therefore formula (8) simplifies to formula (9), thus obtaining the above formula (1):

[0094]

[0095] In this embodiment, the desired front wheel steering angle of the vehicle is predicted based on a first ratio between the wheel speed difference between the two front wheels and the average rear wheel speed, and a second ratio between the wheelbase and track width. This provides a more comprehensive reflection of the vehicle's motion state and geometric characteristics, improving the accuracy of front wheel steering angle prediction and thus optimizing steering response and handling performance, enhancing the driving experience. Furthermore, the method provided in this embodiment can predict the desired front wheel steering angle even when the steering wheel sensor fails or has low accuracy, thereby improving vehicle control stability.

[0096] In some embodiments, step S103 can be implemented by steps S1031 and S1032:

[0097] Step S1031: Based on the current speed of the vehicle, determine the ratio coefficient of the front and rear wheels of the vehicle in a preset mapping table; the preset mapping table includes the correspondence between different vehicle speeds and different ratio coefficients of the front and rear wheels.

[0098] Here, the preset mapping table is a data structure used to store the correspondence between different vehicle speeds and the front and rear wheel ratio coefficients. The function of this mapping table is to quickly find the corresponding front and rear wheel ratio coefficients based on the current vehicle speed.

[0099] In this embodiment of the application, the multiple correspondences in the mapping table refer to the correspondences between different speed ranges and different proportional coefficients. Therefore, it is necessary to first determine the speed range in which the vehicle's current speed falls, and then determine the proportional coefficient among the multiple correspondences based on the speed range. For example, the speed can be divided into low speed range (e.g., <30km / h), medium speed range (e.g., 30-60km / h), and high speed range (e.g., >60km / h).

[0100] In this embodiment of the application, by establishing a mapping relationship between different vehicle speeds and the front and rear wheel ratio coefficients, the vehicle can more accurately match the steering requirements under different driving conditions, thereby improving the vehicle's handling performance and thus improving the driving experience of the driver and passengers.

[0101] Step S1032: Based on the desired front wheel steering angle and the ratio coefficient of the front and rear wheels of the vehicle, determine the desired rear wheel steering angle of the vehicle.

[0102] In this embodiment of the application, the product of the desired front wheel steering angle and the proportional coefficient of the front and rear wheels of the vehicle can be determined as the proportional coefficient of the front and rear wheels of the vehicle.

[0103] In this embodiment, a pre-defined mapping table is used to establish the correspondence between vehicle speed and the front-to-rear wheel ratio coefficients. This allows for the automatic matching of appropriate ratio coefficients at different vehicle speeds, thus more reasonably determining the desired rear wheel steering angle. This avoids the inflexible control issues associated with fixed ratios and enhances the vehicle's adaptability to different speed ranges, thereby improving the overall comfort and stability of steering control.

[0104] In some embodiments, such as Figure 3 As shown, step S104 above can be achieved through steps S301 and S302:

[0105] Step S301: Determine the current moving posture of the vehicle based on the vehicle's steering information and acceleration information.

[0106] Here, steering information is used to characterize whether the vehicle is turning. For example, the steering information may include steering wheel angle information, and if steering wheel angle information is not available, the steering information may also include the vehicle's yaw rate.

[0107] Acceleration information refers to the acceleration or deceleration state of a vehicle in the longitudinal (forward and backward) direction, and is usually collected by a vehicle speed sensor or an inertial measurement unit (IMU). Acceleration information reflects the vehicle's power output or braking status and is a key parameter for determining whether the vehicle is accelerating, decelerating, or moving at a constant speed. For example, during rapid acceleration, the longitudinal acceleration value is large and positive, while during rapid deceleration, it is large and negative.

[0108] In this embodiment of the application, by combining steering information and acceleration information, it is possible to determine whether the vehicle is turning and whether it is accelerating or decelerating.

[0109] Step S302: When the current moving posture is a preset moving posture, adjust the desired rear wheel steering angle based on the front wheel steering of the vehicle, and control the rear wheel steering angle of the vehicle through the adjusted desired rear wheel steering angle.

[0110] Here, the preset movement posture can be at least one of the following: constant speed turning state, acceleration turning state, deceleration turning state, and stable state. Front wheel steering refers to the direction in which the front wheels of the vehicle deflect relative to a straight-ahead state, such as turning left or right.

[0111] In this embodiment of the application, when the vehicle is in a preset moving posture, the direction of the desired rear wheel turning angle can be determined based on the front wheel steering of the vehicle, and the adjusted desired rear wheel turning angle carrying that direction can be obtained. Then, the rear wheels of the vehicle can be controlled to deflect according to the adjusted desired rear wheel turning angle.

[0112] In this embodiment, the current driving posture is determined by comprehensively considering the vehicle's steering and acceleration information, and the desired rear wheel steering angle is adjusted accordingly, making the rear wheel control logic more aligned with actual driving scenarios. This improves the vehicle's adaptability to complex road conditions and enhances its handling performance under specific operating conditions through targeted posture recognition and response mechanisms.

[0113] In some embodiments, step S302 can be implemented by step S3021:

[0114] Step S3021: When the preset moving posture is a constant speed turning state, adjust the direction of the desired turning angle of the rear wheel so that the direction of the desired turning angle of the rear wheel is the same as the direction of the front wheel.

[0115] Here, "uniform speed turning" refers to a vehicle turning at a constant speed. When a vehicle is in a uniform speed turning state, there is little or no change in longitudinal acceleration or deceleration. The driver maintains stable steering input, and the vehicle's yaw rate remains at a stable level. Uniform speed turning typically occurs when the driver maintains stable control after entering a curve without accelerating or decelerating. For example, in a series of curves on a city road or highway, the driver drives the vehicle through the curve at a constant speed; in this situation, the vehicle is in a uniform speed turning state.

[0116] In this embodiment, when the steering information is within a first steering range and the acceleration information is within a first acceleration range, the preset movement posture is determined to be a constant speed turning state. For example, when the steering information is yaw rate, the first steering range is [10~50 degrees / s]; when the steering information is steering wheel speed, the first steering range is [200~700 degrees / s]; the first acceleration range can be ±0.5 m / s². 2 Up to ±2m / s 2 .

[0117] In this embodiment, the front wheel steering is determined as the rear wheel steering, and the rear wheels are controlled to deflect towards the front wheel steering at an angle equal to the desired rear wheel steering angle. Thus, by aligning the desired rear wheel steering angle with the front wheel steering during a constant-speed turn, lateral slippage during cornering can be reduced, thereby improving vehicle stability and enhancing the comfort of the driver and passengers.

[0118] In some embodiments, step S302 can also be implemented by steps S3022 to S3024:

[0119] Step S3022: When the preset moving posture is an accelerating turning state and the current speed of the vehicle is greater than the first speed threshold, control the rear wheels of the vehicle to return to center.

[0120] In this embodiment, when the steering information is within a first steering range and the acceleration information is within a second acceleration range, the preset movement posture is determined to be a constant speed turning state. For example, the second acceleration range can be [2~10m / s²]. 2 In some embodiments, it can also be determined whether the vehicle is accelerating by obtaining the accelerator pedal opening. For example, when the accelerator pedal opening is [50-100%], it is determined that the vehicle is accelerating.

[0121] In this embodiment, when the vehicle's preset movement state is an acceleration and turning state, the vehicle speed can be acquired in real time. When the vehicle's current speed exceeds a first speed threshold, the rear wheels of the vehicle are controlled to return to center. For example, the first speed threshold can be 50 km / h.

[0122] It's understandable that when a vehicle is accelerating through a turn, the driver is increasing the throttle and steering input, resulting in significant power output and steering input. If the rear wheels remain unaligned at high speeds, it can decrease vehicle stability and even increase the risk of loss of control. Therefore, it's necessary to straighten the rear wheels to improve vehicle stability and handling.

[0123] Step S3023: When the current vehicle speed is greater than the second speed threshold, adjust the desired steering angle of the rear wheels based on the steering of the front wheels of the vehicle.

[0124] Step S3024: Control the rear wheel angle of the vehicle by adjusting the desired rear wheel angle so that the front and rear wheels of the vehicle turn in the same direction.

[0125] Here, the second speed threshold is greater than the first speed threshold. For example, the second speed threshold could be 60 km / h.

[0126] In this embodiment, when the vehicle is accelerating and turning, and accelerates to a speed greater than a second speed threshold, the front wheel steering can be used as the deflection direction of the rear wheels, thereby obtaining an adjusted desired rear wheel steering angle carrying the rear wheel deflection direction. Then, the rear wheels of the vehicle are controlled to deflect towards the front wheel steering angle equal to the desired rear wheel steering angle, so that the front and rear wheels of the vehicle steer in the same direction.

[0127] It's understandable that having the front and rear wheels steer in the same direction means that they turn in unison, either to the left or to the right simultaneously. This same steering configuration provides greater stability at high speeds, helps reduce the risk of tire slippage, and improves driving safety and passenger comfort.

[0128] In this embodiment, by setting multiple speed thresholds and combining them with the vehicle's motion state, the desired rear wheel steering angle is controlled in stages, effectively addressing dynamic changes during acceleration and cornering. This ensures, on the one hand, that the rear wheels travel in the same direction as the front wheels at high speeds, improving driving stability; on the other hand, it gradually transitions back to center within the low-to-medium speed range, reducing discomfort caused by sudden steering changes.

[0129] In some embodiments, step S302 can also be implemented by steps S3025 to S3027:

[0130] Step S3025: When the vehicle is in a deceleration and turning state, and the current speed of the vehicle is less than the second speed threshold and greater than the first speed threshold, control the rear wheels of the vehicle to return to center.

[0131] In this embodiment, when the steering information is within a first steering range and the acceleration information is within a third acceleration range, the preset movement posture is determined to be a deceleration turning state. For example, the third acceleration range can be [-20 to -5 m / s²]. 2 In some embodiments, it can also be determined whether the vehicle is decelerating by collecting braking pressure. For example, if the braking pressure is in the range of [50 to 200 bar], it is determined that the vehicle is decelerating.

[0132] In this embodiment of the application, when the vehicle's preset movement state is deceleration and turning, the vehicle speed can be obtained in real time. When the vehicle's current speed is less than the second speed threshold and greater than the first speed threshold, the rear wheels of the vehicle are controlled to return to center.

[0133] Understandably, when a vehicle is decelerating and turning, it indicates that the driver is reducing speed and adjusting lateral position. This typically occurs in urban areas, such as when entering a ramp, avoiding an obstacle, or changing lanes. During deceleration and lane changes, if the rear wheels continue to follow the front wheels in steering, it can increase the feeling of sideslip, thus affecting the driving experience. By straightening the rear wheels, the additional lateral force generated by rear-wheel steering can be reduced, allowing the vehicle to complete the turning maneuver more smoothly.

[0134] Step S3026: When the current vehicle speed is less than the first speed threshold, adjust the desired steering angle of the rear wheels based on the steering of the front wheels of the vehicle.

[0135] Step S3027: Control the rear wheel angle of the vehicle by adjusting the desired rear wheel angle, so that the front and rear wheels of the vehicle turn in opposite directions.

[0136] In this embodiment, when the vehicle is decelerating and turning, and the speed is reduced to less than a first speed threshold, the direction opposite to the front wheel steering can be used as the deflection direction of the rear wheels, thereby obtaining the adjusted desired rear wheel steering angle carrying the rear wheel deflection direction. Then, the rear wheels of the vehicle are controlled to deflect in the direction opposite to the front wheel steering by an angle equal to the desired rear wheel steering angle, thereby making the front and rear wheels of the vehicle turn in opposite directions.

[0137] Understandably, as a vehicle continuously decelerates during a turn, to reduce the turning radius and facilitate maneuvers such as U-turns and turns in narrow areas, the front and rear wheels need to steer in opposite directions. This effectively reduces body roll and enhances the driver's sense of control.

[0138] In this embodiment, when the vehicle is decelerating and changing lanes, and the vehicle's current speed is less than a second speed threshold but greater than a first speed threshold, the rear wheels are controlled to return to center. When the current speed is less than the first speed threshold, the rear wheel steering angle is controlled by adjusting the desired rear wheel steering angle, so that the front and rear wheels steer in opposite directions. This achieves two benefits: firstly, maintaining rear wheel centering within a medium speed range helps maintain vehicle stability; secondly, allowing the front and rear wheels to deflect in opposite directions at low speeds enhances steering agility.

[0139] In some embodiments, step S302 can also be implemented by steps S3028 and S3029:

[0140] Step S3028: When the vehicle is in a stable state and the current speed of the vehicle is less than the first speed threshold, the desired steering angle of the rear wheels is adjusted based on the steering of the front wheels of the vehicle; the rear wheel steering angle of the vehicle is controlled by the adjusted desired steering angle of the rear wheels so that the front and rear wheels of the vehicle steer in opposite directions.

[0141] Here, a stable state refers to a state in which parameters such as acceleration and yaw rate change little during vehicle operation, that is, the vehicle does not accelerate or decelerate violently, nor does it make sharp turns or change lanes.

[0142] In this embodiment, when the vehicle speed is lower than the first speed threshold, it indicates that the vehicle is in a scenario such as an urban road or parking lot, and it is necessary to improve the steering sensitivity and flexibility of the vehicle. Therefore, the vehicle sets the rear wheels to steer in the opposite direction to the front wheels, thereby effectively reducing the turning radius and improving the vehicle's ability to pass through narrow spaces.

[0143] Step S3029: When the current vehicle speed is greater than the second speed threshold, adjust the desired rear wheel steering angle based on the front wheel steering of the vehicle; control the rear wheel steering angle of the vehicle by adjusting the desired rear wheel steering angle so that the front and rear wheels of the vehicle steer in the same direction.

[0144] In this embodiment, the vehicle determines whether it is in a high-speed stable state by using a second speed threshold. When the vehicle's speed exceeds this second speed threshold, the vehicle is typically operating in road environments such as highways or expressways, where stability and safety during driving are of paramount importance. The control system employs a front and rear wheel steering strategy in the same direction to improve vehicle stability during driving and prevent the risk of loss of control due to rear wheel steering in the opposite direction.

[0145] In this embodiment, when the vehicle is in a stable state and its current speed is less than a first speed threshold, the rear wheel steering angle is controlled by adjusting the desired rear wheel steering angle, causing the front and rear wheels to steer in opposite directions. When the current speed is greater than a second speed threshold, the rear wheel steering angle is controlled by adjusting the desired rear wheel steering angle, causing the front and rear wheels to steer in the same direction. Thus, on the one hand, opposing wheel deflections improve steering sensitivity in low-speed steady-state conditions; on the other hand, unidirectional deflections enhance driving stability in high-speed steady-state conditions.

[0146] In some embodiments, when the vehicle is in a stable state, the above method can also be implemented through steps S11 and S12:

[0147] Step S11: During the process of the vehicle accelerating from the first speed threshold to the second speed threshold, the front and rear wheels of the vehicle are kept in opposite directions.

[0148] In this embodiment of the application, the vehicle speed of the vehicle in a stable state is continuously acquired. Because the vehicle is in a stable state, the vehicle acceleration is small, that is, the vehicle is accelerating with a small acceleration. When the vehicle speed is between the first speed threshold and the second speed threshold, the front and rear wheels of the vehicle can be kept in opposite directions. In this process, the rear wheel steering angle of the vehicle can be determined based on the expected front wheel steering angle, which is determined by steps S201 to S205.

[0149] Step S12: During the process of the vehicle decelerating from the second speed threshold to the first speed threshold, the steering of the front and rear wheels of the vehicle remains the same.

[0150] In this embodiment of the application, the vehicle speed of the vehicle in a stable state is continuously acquired. Because the vehicle is in a stable state, the deceleration of the vehicle is small, that is, the vehicle is decelerating at a small deceleration. When the vehicle speed is between the second speed threshold and the first speed threshold, the steering of the front and rear wheels of the vehicle can be kept the same. In this process, the rear wheel steering angle of the vehicle can be determined based on the expected front wheel steering angle, which is determined by steps S201 to S205.

[0151] In this embodiment, during the process of a vehicle accelerating from a first speed threshold to a second speed threshold while in a stable state, the front and rear wheels maintain opposite steering directions; conversely, during the process of a vehicle decelerating from the second speed threshold to the first speed threshold while in a stable state, the front and rear wheels maintain the same steering direction. By maintaining the consistency or oppositeity of the steering directions of the front and rear wheels during speed changes, frequent switching of steering control is reduced, thereby improving the driving experience.

[0152] The following describes the application of the wheel angle control method provided in this application embodiment in a real-world scenario:

[0153] As existing vehicle models have increasingly longer wheelbases, a larger turning radius is required. Adding a rear-wheel steering system can effectively reduce the turning radius and improve vehicle agility. A rear-wheel steering system adds a steering mechanism to the rear suspension. At low speeds, it drives the rear wheels to turn in the opposite direction to the front wheels, improving the vehicle's low-speed steering sensitivity and reducing the turning diameter, making urban driving more flexible and convenient. At high speeds, it drives the rear wheels to turn in the same direction as the front wheels, enhancing stability and safety during high-speed driving.

[0154] In related technologies, the target rear wheel steering angle is usually calculated based on vehicle speed and steering wheel angle. This method is difficult to adapt to complex and ever-changing road conditions due to the limited input signals, and the comfort level is greatly reduced in some road conditions.

[0155] To address the problems existing in the above solutions, this invention proposes a novel rear-wheel steering control method to improve the driving experience. This method collects signals such as vehicle speed, longitudinal acceleration, yaw rate, steering wheel speed, accelerator pedal opening, brake pressure, and steering wheel angle. Based on these signals, the vehicle's driving state is determined, and different control methods are selected accordingly. Multiple selectable control methods can effectively improve the driving experience for both driver and passengers.

[0156] In this embodiment of the application, the wheel rotation angle control method can be implemented through steps S110 to S130:

[0157] S110: Obtain longitudinal acceleration, vehicle speed, accelerator pedal opening, and steering wheel angle.

[0158] S120. Determine whether the vehicle is in its first motion posture.

[0159] In this embodiment, the first motion posture represents the vehicle's rapid acceleration state, where the vehicle speed is greater than a first vehicle speed threshold (50 km / h) and the longitudinal acceleration is between 2 and 10 m / s². 2 When the accelerator pedal opening is between [50% and 100%] and the steering wheel angle is between [0° and 50°], the vehicle is determined to be in the first motion posture.

[0160] S130, When the vehicle is in its first motion posture, control the rear wheels of the vehicle.

[0161] In this embodiment of the application, the first motion posture can improve the discomfort caused by the rapid switching of the front and rear wheels from opposite deflection to same deflection during rapid acceleration.

[0162] In some embodiments, the above control method can also be implemented through steps S210 to S230:

[0163] S210: Obtain longitudinal acceleration, vehicle speed, braking pressure, and steering wheel angle.

[0164] S220, Determine whether the vehicle is in the second motion posture.

[0165] In this embodiment, the second motion posture represents the vehicle's rapid deceleration state, where the vehicle speed is less than the first vehicle speed threshold (50 km / h) and the longitudinal acceleration is between -20 and -5 m / s². 2 When the braking pressure is between [50 and 200 bar] and the steering wheel angle is between [0 and 50°], the vehicle is determined to be in the second motion posture.

[0166] S230, When the vehicle is in the second motion posture, control the rear wheels of the vehicle.

[0167] In this embodiment, the second motion posture can improve the discomfort caused by the rapid switching of the front and rear wheels from swerving in the same direction to swerving in opposite directions during rapid deceleration.

[0168] In some embodiments, the above control method can also be implemented through steps S310 to S340:

[0169] S310: Obtain yaw rate and steering wheel speed.

[0170] S320, Determine whether the vehicle is in the third motion posture.

[0171] In this embodiment, the third motion posture represents a normal lane change state. The vehicle is determined to be in the third motion posture when the yaw rate is between 10 and 50 degrees / s and the steering wheel speed is between 200 and 700 degrees / s.

[0172] S330. When the vehicle is in the third motion posture, determine the rear wheel steering angle.

[0173] In this embodiment of the application, the desired front wheel steering angle of the vehicle can be determined by formula (1), and then the rear wheel steering angle of the rear wheel can be determined based on the desired front wheel steering angle of the vehicle.

[0174] S340. The rear wheel steering angle is symbolically processed, and the change of the rear wheel steering angle is controlled by the symbolically processed rear wheel steering angle so that it remains in the same direction as the front wheel steering angle.

[0175] Symbol processing can be achieved using formula (10):

[0176] Rear wheel steering angle × (Sign (direction of front wheel steering angle)) formula (10).

[0177] In this embodiment, the third motion posture can improve the discomfort caused by the large yaw during rapid lane changes.

[0178] In some embodiments, the above control method can also be implemented through steps S410 to S450:

[0179] S410: Obtain longitudinal acceleration, accelerator pedal opening, yaw rate, and steering wheel speed.

[0180] S420, Determine whether the vehicle is in the fourth motion posture.

[0181] In this embodiment, the fourth motion posture represents a rapid acceleration lane change. The longitudinal acceleration is between 2 and 10 m / s².2 When the accelerator pedal opening is between [50-100%], the yaw speed is between [10-50 degrees / s], and the steering wheel speed is between [200-700 degp / s], the vehicle is determined to be in the fourth motion posture.

[0182] S430. When the vehicle is in the fourth motion posture, determine the rear wheel steering angle.

[0183] In this embodiment of the application, the desired front wheel steering angle of the vehicle can be determined by formula (1), and then the rear wheel steering angle of the rear wheel can be determined based on the desired front wheel steering angle of the vehicle.

[0184] S440. When the vehicle speed is greater than the first threshold (50km / h), the rear wheel steering angle is controlled to return to center based on the real-time collected rear wheel steering angle.

[0185] S450 When the vehicle speed is greater than the second threshold (60km / h), the rear wheel steering angle is controlled by the symbol-processed rear wheel steering angle to make it turn in the same direction as the front wheel steering angle.

[0186] Symbol processing can be achieved through formula (10).

[0187] In this embodiment, the fourth motion posture can improve the vehicle's response during rapid acceleration and lane changes.

[0188] In some embodiments, the above control method can also be implemented through steps S510 to S550:

[0189] S510: Obtain longitudinal acceleration, braking pressure, yaw rate, and steering wheel speed.

[0190] S520, Determine whether the vehicle is in the fifth motion posture.

[0191] In this embodiment, the fifth motion posture represents a rapid deceleration and lane change state. The longitudinal acceleration is between -20 and -5 m / s². 2 When the braking pressure is between [50 and 200 bar], the yaw rate is between [10 and 50 degrees / s], and the steering wheel speed is between [200 and 700 degp / s], the vehicle is determined to be in the fifth motion posture.

[0192] S530. When the vehicle is in the fifth motion posture, determine the rear wheel steering angle.

[0193] In this embodiment of the application, the desired front wheel steering angle of the vehicle can be determined by formula (1), and then the rear wheel steering angle of the rear wheel can be determined based on the desired front wheel steering angle of the vehicle.

[0194] S540. When the vehicle speed is less than the second threshold (60km / h), the rear wheel steering angle is controlled to return to center based on the real-time collected rear wheel steering angle.

[0195] S550 When the vehicle speed is less than the first threshold (50km / h), the rear wheel steering angle is controlled by the symbol-processed rear wheel steering angle to make it turn in the opposite direction to the front wheel steering angle.

[0196] Symbol processing can be achieved through formula (10).

[0197] In this embodiment, the fifth motion posture can improve the vehicle's response during rapid deceleration and lane changes.

[0198] In some embodiments, the above control method can also be implemented through steps S610 to S650:

[0199] S610 acquires longitudinal acceleration, vehicle speed, accelerator pedal opening, steering wheel angle, yaw rate, steering wheel speed, and braking pressure.

[0200] S620, Determine whether the vehicle is in the sixth motion posture.

[0201] In this embodiment, the sixth motion posture represents a steady state. The vehicle is determined to be in the sixth motion posture when it is determined that the vehicle does not belong to any of the above motion states based on longitudinal acceleration, vehicle speed, accelerator pedal opening, steering wheel angle, yaw rate, steering wheel speed, and braking pressure.

[0202] S630. When the vehicle is in the sixth motion posture, determine the rear wheel steering angle.

[0203] In this embodiment of the application, the desired front wheel steering angle of the vehicle can be determined by formula (1), and then the rear wheel steering angle of the rear wheel can be determined based on the desired front wheel steering angle of the vehicle.

[0204] S640. When the vehicle speed is less than the first threshold (50km / h), the rear wheel angle is controlled based on the symbol-processed rear wheel angle to make the front and rear wheels reverse direction.

[0205] S650: When the vehicle speed increases from the first threshold to the second threshold, the front and rear wheels remain in opposite directions.

[0206] S660. During the process of the vehicle speed decreasing from the second threshold to the first threshold, the front and rear wheels remain in the same direction.

[0207] S670 When the vehicle speed is less than the first threshold (50km / h), the rear wheel angle is controlled based on the symbol-processed rear wheel angle to make the front and rear wheels reverse direction.

[0208] When the vehicle speed is less than the second threshold (60km / h), the rear wheel steering angle is controlled to return to center based on the real-time collected rear wheel steering angle.

[0209] S550 When the vehicle speed is greater than the second threshold (60km / h), the rear wheel angle is controlled by the symbol-processed rear wheel angle to make it align with the front wheel angle in the same direction.

[0210] In some embodiments, such as Figure 4 As shown, this application embodiment provides a wheel angle control device 400, which includes an acquisition module 401, a prediction module 402, a determination module 403, and a control module 404; wherein:

[0211] The acquisition module 401 is used to acquire the first wheel speed information of the front wheels of the vehicle and the second wheel speed information of the rear wheels of the vehicle;

[0212] Prediction module 402 is used to predict the desired steering angle of the front wheels of the vehicle based on the first wheel speed information and the second wheel speed information;

[0213] The determining module 403 is used to determine the desired steering angle of the rear wheels of the vehicle based on the desired steering angle of the front wheels;

[0214] The control module 404 is used to adjust the desired rear wheel steering angle based on the current moving posture of the vehicle, and to control the rear wheel steering angle of the vehicle through the adjusted desired rear wheel steering angle.

[0215] In some embodiments, the prediction module 402 is further configured to: determine the wheel speed difference between the two front wheels of the vehicle based on the first wheel speed information; determine the average rear wheel speed of the two rear wheels of the vehicle based on the second wheel speed information; determine a first ratio between the wheel speed difference between the two front wheels of the vehicle and the average rear wheel speed of the two rear wheels of the vehicle; determine a second ratio between the wheelbase of the vehicle and the track width of the vehicle; and determine the desired front wheel steering angle of the vehicle based on the first ratio and the second ratio.

[0216] In some embodiments, the determining module 403 is further configured to determine the ratio coefficients of the front and rear wheels of the vehicle based on the current speed of the vehicle in a preset mapping table; the preset mapping table includes the correspondence between different vehicle speeds and different ratio coefficients of the front and rear wheels; and to determine the expected steering angle of the rear wheels of the vehicle based on the expected steering angle of the front wheels and the ratio coefficients of the front and rear wheels of the vehicle.

[0217] In some embodiments, the control module 404 is further configured to determine the current moving posture of the vehicle based on the vehicle's steering information and the vehicle's acceleration information; if the current moving posture is a preset moving posture, adjust the desired rear wheel steering angle based on the front wheel steering of the vehicle, and control the rear wheel steering angle of the vehicle through the adjusted desired rear wheel steering angle.

[0218] In some embodiments, the control module 404 is further configured to adjust the direction of the desired rear wheel turning angle when the preset moving posture is a constant speed turning state, so that the direction of the desired rear wheel turning angle is the same as the direction of the front wheel turning.

[0219] In some embodiments, the control module 404 is further configured to: control the rear wheels of the vehicle to return to center when the preset moving posture is an acceleration turning state and the current speed of the vehicle is greater than a first speed threshold; and adjust the desired steering angle of the rear wheels based on the steering of the front wheels of the vehicle when the current speed is greater than a second speed threshold; wherein the second speed threshold is greater than the first speed threshold; and control the steering angle of the rear wheels of the vehicle by adjusting the desired steering angle of the rear wheels so that the steering of the front and rear wheels of the vehicle is the same.

[0220] In some embodiments, the control module 404 is further configured to: control the rear wheels of the vehicle to return to center when the vehicle is in a deceleration and turning state and the current speed of the vehicle is less than a second speed threshold and greater than a first speed threshold; adjust the desired steering angle of the rear wheels based on the steering of the front wheels of the vehicle when the current speed is less than the first speed threshold; and control the steering angle of the rear wheels of the vehicle by adjusting the desired steering angle of the rear wheels so that the front and rear wheels of the vehicle steer in opposite directions.

[0221] In some embodiments, the control module 404 is further configured to: when the vehicle is in a stable state and the current speed of the vehicle is less than a first speed threshold, adjust the desired rear wheel steering angle based on the front wheel steering of the vehicle; control the rear wheel steering angle of the vehicle through the adjusted desired rear wheel steering angle so that the front and rear wheels of the vehicle steer in opposite directions; when the current speed is greater than a second speed threshold, adjust the desired rear wheel steering angle based on the front wheel steering of the vehicle; control the rear wheel steering angle of the vehicle through the adjusted desired rear wheel steering angle so that the front and rear wheels of the vehicle steer in the same direction.

[0222] In some embodiments, the control module 404 is further configured to maintain the opposite steering of the front and rear wheels of the vehicle during the process of the vehicle accelerating from the first speed threshold to the second speed threshold; and to maintain the same steering of the front and rear wheels of the vehicle during the process of the vehicle decelerating from the second speed threshold to the first speed threshold.

[0223] The descriptions of the apparatus embodiments above are similar to those of the method embodiments above, and have similar beneficial effects. In some embodiments, the functions or modules included in the apparatus provided in this disclosure can be used to perform the methods described in the method embodiments above. For technical details not disclosed in the apparatus embodiments of this application, please refer to the descriptions of the method embodiments of this application for understanding.

[0224] It should be noted that, in the embodiments of this application, if the above-described data processing method is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the embodiments of this application, or the part that contributes to the related technology, can be embodied in the form of a software product. This software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, mobile hard drives, read-only memory (ROM), magnetic disks, or optical disks. Thus, the embodiments of this application are not limited to any specific hardware, software, or firmware, or any combination of hardware, software, and firmware.

[0225] This application provides a computer device including a memory and a processor. The memory stores a computer program that can run on the processor. When the processor executes the program, it implements some or all of the steps in the above-described method.

[0226] This application provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements some or all of the steps in the above-described method. The computer-readable storage medium can be transient or non-transient.

[0227] This application provides a computer program including computer-readable code, wherein when the computer-readable code is executed in a computer device, a processor in the computer device performs some or all of the steps in the above-described method.

[0228] This application provides a computer program product, which includes a non-transitory computer-readable storage medium storing a computer program. When the computer program is read and executed by a computer, it implements some or all of the steps in the above-described method. This computer program product can be implemented specifically through hardware, software, or a combination thereof. In some embodiments, the computer program product is specifically embodied as a computer storage medium; in other embodiments, the computer program product is specifically embodied as a software product, such as a software development kit (SDK), etc.

[0229] It should be noted that the descriptions of the various embodiments above tend to emphasize the differences between them, while their similarities or commonalities can be referred to interchangeably. The descriptions of the above embodiments of the device, storage medium, computer program, and computer program product are similar to the descriptions of the above method embodiments and have similar beneficial effects. For technical details not disclosed in the embodiments of the device, storage medium, computer program, and computer program product of this application, please refer to the descriptions of the method embodiments of this application for understanding.

[0230] Figure 5 This is a schematic diagram of the composition of a wheel rotation angle control device 500 provided in an embodiment of this application, as shown below. Figure 5 As shown, the device includes: a processor 501, a communication interface 502, and a memory 503, wherein:

[0231] The processor 501 typically controls the overall operation of the control device 500 for the wheel rotation angle, and the overall operation may be to implement the wheel rotation angle control method provided in the embodiments of this application.

[0232] The communication interface 502 enables the wheel rotation angle control device 500 to communicate with other terminals or servers via a network.

[0233] The memory 503 is configured to store instructions and applications executable by the processor 501, and can also cache data to be processed or already processed (e.g., image data, audio data, voice communication data, and video communication data) in the processor 501 and the various modules in the wheel angle control device 500. It can be implemented using flash memory or random access memory (RAM). Data transfer between the processor 501, the communication interface 502, and the memory 503 can be performed via bus 504.

[0234] This application provides a computer program product or computer program that includes computer instructions stored in a readable storage medium. A processor of a computer device reads the computer instructions from the readable storage medium and executes the computer instructions, causing the computer device to perform the wheel angle control method described above in this application.

[0235] This application provides a readable storage medium storing executable instructions. When the executable instructions are executed by a processor, the processor will execute the wheel angle control method provided in this application.

[0236] It should be noted that the descriptions of the storage medium and device embodiments above are similar to those of the method embodiments above, and have similar beneficial effects. For technical details not disclosed in the storage medium and device embodiments of this application, please refer to the descriptions of the method embodiments of this application for understanding.

[0237] The aforementioned processor can be at least one of the following: Application Specific Integrated Circuit (ASIC), Digital Signal Processor (DSP), Digital Signal Processing Device (DSPD), Programmable Logic Device (PLD), Field Programmable Gate Array (FPGA), Central Processing Unit (CPU), Controller, Microcontroller, and Microprocessor. It is understood that other electronic devices can also implement the functions of the aforementioned processor, and this application does not specifically limit the specific implementation.

[0238] The aforementioned computer storage media / memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic random access memory (FRAM), flash memory, magnetic surface memory, optical disc, or compact disc read-only memory (CD-ROM), etc.; or it can be various terminals that include one or any combination of the above-mentioned memories, such as mobile phones, computers, tablet devices, personal digital assistants, etc.

[0239] It should be understood that the phrase "one embodiment" or "an embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It should be understood that in the various embodiments of this application, the sequence numbers of the above steps / processes do not imply a sequential order of execution; the execution order of each step / process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application. The sequence numbers of the above embodiments of this application are merely descriptive and do not represent the superiority or inferiority of the embodiments.

[0240] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0241] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods, such as: multiple units or components can be combined, or integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the various components shown or discussed can be through some interfaces, and the indirect coupling or communication connection between devices or units can be electrical, mechanical, or other forms.

[0242] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units. They may be located in one place or distributed across multiple network units. Some or all of the units may be selected to achieve the purpose of this embodiment according to actual needs.

[0243] In addition, each functional unit in the various embodiments of this application can be integrated into one processing unit, or each unit can be a separate unit, or two or more units can be integrated into one unit; the integrated unit can be implemented in hardware or in the form of hardware plus software functional units.

[0244] Those skilled in the art will understand that all or part of the steps of the above method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments. The aforementioned storage medium includes various media that can store program code, such as mobile storage devices, read-only memory (ROM), magnetic disks, or optical disks.

[0245] Alternatively, if the integrated units described above are implemented as software functional modules and sold or used as independent products, they can also be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence or the part that contributes to related technologies, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as mobile storage devices, ROM, magnetic disks, or optical disks.

[0246] The above description is merely an embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A method for controlling the steering angle of a wheel, characterized in that, The method for controlling the wheel rotation angle includes: Obtain the first wheel speed information of the front wheels of the vehicle and the second wheel speed information of the rear wheels of the vehicle; Based on the first wheel speed information and the second wheel speed information, predict the expected steering angle of the vehicle's front wheels; Based on the vehicle's current speed, the ratio coefficients of the front and rear wheels of the vehicle are determined in a preset mapping table; the preset mapping table includes the correspondence between different vehicle speeds and different ratio coefficients of the front and rear wheels. Based on the desired steering angle of the front wheels and the ratio coefficient between the front and rear wheels of the vehicle, the desired steering angle of the rear wheels of the vehicle is determined. Based on the vehicle's steering information and acceleration information, the vehicle's current movement posture is determined; When the current moving posture is a preset moving posture, the desired rear wheel steering angle is adjusted based on the front wheel steering of the vehicle, and the rear wheel steering angle of the vehicle is controlled by the adjusted desired rear wheel steering angle.

2. The wheel angle control method according to claim 1, characterized in that, The step of predicting the desired front wheel steering angle of the vehicle based on the first wheel speed information and the second wheel speed information includes: Based on the first wheel speed information, the wheel speed difference between the two front wheels of the vehicle is determined; Based on the second wheel speed information, the average rear wheel speed of the two rear wheels of the vehicle is determined; Determine a first ratio between the wheel speed difference between the two front wheels of the vehicle and the average rear wheel speed of the two rear wheels of the vehicle; Determine a second ratio between the vehicle's wheelbase and its track width; Based on the first ratio and the second ratio, the desired steering angle of the vehicle's front wheels is determined.

3. The wheel angle control method according to claim 1, characterized in that, When the current moving posture is a preset moving posture, adjusting the desired steering angle of the rear wheels based on the steering of the front wheels of the vehicle includes: When the preset movement posture is a constant speed turning state, adjust the direction of the desired turning angle of the rear wheel so that the direction of the desired turning angle of the rear wheel is the same as the direction of the front wheel.

4. The method for controlling wheel rotation angle according to claim 1, characterized in that, When the current moving posture is a preset moving posture, adjusting the desired rear wheel steering angle based on the front wheel steering of the vehicle, and controlling the rear wheel steering angle of the vehicle through the adjusted desired rear wheel steering angle, includes: When the preset movement posture is an accelerated turning state and the current speed of the vehicle is greater than a first speed threshold, the rear wheels of the vehicle are controlled to return to center. If the current vehicle speed is greater than a second speed threshold, the desired steering angle of the rear wheels is adjusted based on the steering of the front wheels of the vehicle; wherein the second speed threshold is greater than the first speed threshold. The rear wheel steering angle of the vehicle is controlled by adjusting the desired rear wheel steering angle, so that the front and rear wheels of the vehicle steer in the same direction.

5. The wheel angle control method according to claim 1, characterized in that, When the current moving posture is a preset moving posture, adjusting the desired rear wheel steering angle based on the front wheel steering of the vehicle, and controlling the rear wheel steering angle of the vehicle through the adjusted desired rear wheel steering angle, includes: When the vehicle is in a deceleration and turning state, and the current speed of the vehicle is less than the second speed threshold and greater than the first speed threshold, control the rear wheels of the vehicle to return to center. When the current vehicle speed is less than a first speed threshold, the desired steering angle of the rear wheels is adjusted based on the steering of the front wheels of the vehicle; the rear wheel steering angle of the vehicle is controlled by the adjusted desired steering angle of the rear wheels, so that the front and rear wheels of the vehicle steer in opposite directions.

6. The wheel angle control method according to claim 1, characterized in that, When the current moving posture is a preset moving posture, adjusting the desired rear wheel steering angle based on the front wheel steering of the vehicle, and controlling the rear wheel steering angle of the vehicle through the adjusted desired rear wheel steering angle, includes: When the vehicle is in a stable state and the current speed of the vehicle is less than a first speed threshold, the desired steering angle of the rear wheels is adjusted based on the steering of the front wheels of the vehicle; the rear wheel steering angle of the vehicle is controlled by the adjusted desired steering angle of the rear wheels, so that the front and rear wheels of the vehicle steer in opposite directions; When the current vehicle speed is greater than the second speed threshold, the desired steering angle of the rear wheels is adjusted based on the steering of the front wheels of the vehicle; the rear wheel steering angle of the vehicle is controlled by the adjusted desired steering angle of the rear wheels so that the front and rear wheels of the vehicle are steering in the same direction.

7. The wheel angle control method according to claim 6, characterized in that, When the vehicle is in a stable state, the method further includes: During the process of the vehicle accelerating from the first speed threshold to the second speed threshold, the front and rear wheels of the vehicle are kept in opposite directions. During the process of the vehicle decelerating from the second speed threshold to the first speed threshold, the steering of the front and rear wheels of the vehicle remains the same.

8. A wheel steering angle control device, characterized in that, The wheel rotation angle control device includes: The acquisition module is used to acquire the first wheel speed information of the front wheels of the vehicle and the second wheel speed information of the rear wheels of the vehicle; The prediction module is used to predict the desired steering angle of the front wheels of the vehicle based on the first wheel speed information and the second wheel speed information. The determination module is used to determine the ratio coefficients of the front and rear wheels of the vehicle based on the current speed of the vehicle in a preset mapping table; the preset mapping table includes the correspondence between different vehicle speeds and different ratio coefficients of the front and rear wheels; and to determine the expected steering angle of the rear wheels of the vehicle based on the expected steering angle of the front wheels and the ratio coefficients of the front and rear wheels of the vehicle. The control module is used to determine the current moving posture of the vehicle based on the vehicle's steering information and acceleration information; when the current moving posture is a preset moving posture, it adjusts the desired steering angle of the rear wheels based on the steering of the front wheels of the vehicle, and controls the steering angle of the rear wheels of the vehicle through the adjusted desired steering angle.

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