Vehicle steering control method and related equipment

Abstract

The invention relates to a vehicle steering control method and related equipment, and the method comprises the steps: obtaining a steering wheel turning angle of a vehicle when the vehicle turns; if the front wheel distance between the left front wheel and the right front wheel of the vehicle is different from the standard front wheel distance, the turning angle of the left front wheel and the turning angle of the right front wheel are controlled based on the front wheel distance and the turning angle of the steering wheel, and / or if the rear wheel distance between the left rear wheel and the right rear wheel of the vehicle is different from the standard rear wheel distance, the turning angle is controlled. And controlling the turning angle of the left rear wheel and the turning angle of the right rear wheel based on the rear wheel distance and the steering wheel turning angle, so that the distance between the intersection point of the axle extension lines of the left front wheel and the right front wheel and the intersection point of the axle extension lines of the left rear wheel and the right rear wheel is less than or equal to 20cm. The method can improve the steering stability of the vehicle.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicles, in particular to a steering control method of a vehicle and related equipment. BACKGROUND

[0002] In order to adapt to the road running environment such as narrow road or obstacle crossing, a variable wheel track vehicle is a future development trend. At present, most researches focus on the hardware structure of wheel track adjustment, but less attention is paid to the problem of vehicle steering stability caused by variable wheel track. SUMMARY

[0003] The embodiments of the present application provide a steering control method of a vehicle and related equipment, which can improve the stability of vehicle steering.

[0004] In order to achieve the above-mentioned purpose, according to a first aspect of the present application, a steering control method of a vehicle is provided, the vehicle comprising a steering wheel, a left front wheel, a right front wheel, a left rear wheel and a right rear wheel. The method comprises: obtaining a steering wheel angle when the vehicle is steering. If a front wheel track between the left front wheel and the right front wheel is different from a reference front wheel track, controlling a turning angle of the left front wheel and a turning angle of the right front wheel based on the front wheel track and the steering wheel angle, and / or if a rear wheel track between the left rear wheel and the right rear wheel is different from a reference rear wheel track, controlling a turning angle of the left rear wheel and a turning angle of the right rear wheel based on the rear wheel track and the steering wheel angle, so that a distance between a wheel axle extension line intersection point of the left front wheel and the right front wheel and a wheel axle extension line intersection point of the left rear wheel and the right rear wheel is less than or equal to 20 cm.

[0005] Optionally, the controlling the turning angle of the left front wheel and the turning angle of the right front wheel based on the front wheel track and the steering wheel angle comprises: determining a front wheel reference turning angle based on the steering wheel angle; determining a rear wheel reference turning angle based on the front wheel reference turning angle; determining a turning angle direction and a value of the left front wheel and determining a turning angle direction and a value of the right front wheel based on the front wheel reference turning angle, the rear wheel reference turning angle and the front wheel track; and controlling the turning angle of the left front wheel and the turning angle of the right front wheel based on the turning angle direction and the value of the left front wheel and the turning angle direction and the value of the right front wheel.

[0006] Optionally, the determining the turning angle direction and the value of the left front wheel and the determining the turning angle direction and the value of the right front wheel based on the front wheel reference turning angle, the rear wheel reference turning angle and the front wheel track comprises: calculating the turning angle direction and the value of the left front wheel and the turning angle direction and the value of the right front wheel through the following formula:

[0007]

[0008] wherein, a direction and a value of a steering angle of the left front wheel, a direction and a value of a steering angle of the right front wheel, a front wheel reference steering angle, a rear wheel reference steering angle, a front wheel track, a wheelbase of the vehicle.

[0009] Optionally, a change of the steering angle of the left front wheel compared to the left front wheel reference steering angle is opposite to a change of the steering angle of the right front wheel compared to the right front wheel reference steering angle, wherein the left front wheel reference steering angle and the right front wheel reference steering angle are both determined based on the reference front wheel track and the steering wheel angle.

[0010] Optionally, if the front wheel track is greater than the reference front wheel track, the steering angle of the left front wheel is increased compared to the left front wheel reference steering angle, and the steering angle of the right front wheel is decreased compared to the right front wheel reference steering angle. If the front wheel track is less than the reference front wheel track, the steering angle of the left front wheel is decreased compared to the left front wheel reference steering angle, and the steering angle of the right front wheel is increased compared to the right front wheel reference steering angle.

[0011] Optionally, the controlling the steering angle of the left rear wheel and the steering angle of the right rear wheel based on the rear wheel track and the steering wheel angle comprises: determining a front wheel reference steering angle based on the steering wheel angle; determining a rear wheel reference steering angle based on the front wheel reference steering angle; determining a direction and a value of a steering angle of the left rear wheel and determining a direction and a value of a steering angle of the right rear wheel based on the front wheel reference steering angle, the rear wheel reference steering angle and the rear wheel track; and controlling the steering angle of the left rear wheel and the steering angle of the right rear wheel based on the direction and the value of the steering angle of the left rear wheel and the direction and the value of the steering angle of the right rear wheel.

[0012] Optionally, the determining the direction and the value of the steering angle of the left rear wheel and the determining the direction and the value of the steering angle of the right rear wheel based on the front wheel reference steering angle, the rear wheel reference steering angle and the rear wheel track comprises: calculating the direction and the value of the steering angle of the left rear wheel and the direction and the value of the steering angle of the right rear wheel by the following formula:

[0013]

[0014] wherein, a direction and a value of a steering angle of the left rear wheel, a direction and a value of a steering angle of the right rear wheel, a front wheel reference steering angle, a rear wheel reference steering angle, a rear wheel track, a wheelbase of the vehicle.

[0015] Optionally, the change in the steering angle of the left rear wheel relative to the reference steering angle of the left rear wheel is opposite to the change in the steering angle of the right rear wheel relative to the reference steering angle of the right rear wheel, wherein the reference steering angle of the left rear wheel and the reference steering angle of the right rear wheel are both determined based on the reference rear track and the steering wheel angle.

[0016] Optionally, if the rear wheel track is greater than the reference rear wheel track, when the reference steering angle of the front wheel and the reference steering angle of the rear wheel are in the same direction, the steering angle of the left rear wheel is larger than the reference steering angle of the left rear wheel, and the steering angle of the right rear wheel is smaller than the reference steering angle of the right rear wheel; when the reference steering angle of the front wheel and the reference steering angle of the rear wheel are in opposite directions, the steering angle of the left rear wheel is smaller than the reference steering angle of the left rear wheel, and the steering angle of the right rear wheel is larger than the reference steering angle of the right rear wheel. If the rear wheel track is less than the reference rear wheel track, when the reference steering angle of the front wheel and the reference steering angle of the rear wheel are in the same direction, the steering angle of the left rear wheel is smaller than the reference steering angle of the left rear wheel, and the steering angle of the right rear wheel is larger than the reference steering angle of the right rear wheel; when the reference steering angle of the front wheel and the reference steering angle of the rear wheel are in opposite directions, the steering angle of the left rear wheel is larger than the reference steering angle of the left rear wheel, and the steering angle of the right rear wheel is smaller than the reference steering angle of the right rear wheel.

[0017] Optionally, if the rear wheel track is greater than or less than the reference rear wheel track, when the reference front wheel angle and the reference rear wheel angle are in the same or different directions, if the front wheel track is greater than the reference front wheel track, the angle of the left front wheel is larger than the reference left front wheel angle, and the angle of the right front wheel is smaller than the reference right front wheel angle; if the front wheel track is the same as the reference front wheel track, the angle of the left front wheel is the reference left front wheel angle, and the angle of the right front wheel is the reference right front wheel angle; if the front wheel track is less than the reference front wheel track, the angle of the left front wheel is smaller than the reference left front wheel angle, and the angle of the right front wheel is larger than the reference right front wheel angle.

[0018] Optionally, the direction of the rear wheel reference angle is the direction of the first rear wheel reference angle. The value of the rear wheel reference angle is the minimum value between the absolute value of the front wheel reference angle and the absolute value of the first rear wheel reference angle. The first rear wheel reference angle is determined based on the front wheel reference angle, yaw rate, and vehicle speed.

[0019] Optionally, the distance between the intersection point of the axle extension lines of the left front wheel and the right front wheel, and the intersection point of the axle extension lines of the left rear wheel and the right rear wheel is less than or equal to 10 centimeters.

[0020] According to a second aspect of this application, an electronic device is provided, comprising: a memory having a computer program stored thereon; and a processor for executing the computer program in the memory to implement the aforementioned vehicle steering control method.

[0021] According to a third aspect of this application, a vehicle is provided, the vehicle including a wheel track adjustment device and the aforementioned electronic equipment.

[0022] According to a fourth aspect of this application, a computer program product is provided, comprising a computer program that, when executed by a processor, implements the aforementioned vehicle steering control method.

[0023] The steering control method of this application combines driver input (corresponding to changes in steering wheel angle) and track width changes to control the wheels to perform pure rolling motion when the vehicle is turning. This enhances vehicle steering stability, reduces the risk of sideslip, reduces tire wear, and improves driving safety. It is particularly suitable for dangerous situations such as needing to adjust track width when encountering obstacles on a turning road. Furthermore, this steering control method can be applied to vehicles with adjustable front track width only, vehicles with adjustable rear track width only, and vehicles with adjustable track width for both front and rear wheels, making it widely applicable and supporting diverse scenarios.

[0024] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the structure of a wheel track adjustment device provided in an embodiment of this application;

[0027] Figure 2 This is a schematic diagram of a steering scenario for a vehicle with a fixed wheelbase, as described in an embodiment of this application.

[0028] Figure 3 This is a schematic diagram of a steering scenario for a vehicle with a variable wheelbase, as described in an embodiment of this application.

[0029] Figure 4 This is a schematic flowchart of a vehicle steering control method provided in an embodiment of this application;

[0030] Figure 5 This is a schematic flowchart of another vehicle steering control method provided in an embodiment of this application;

[0031] Figure 6 This is a schematic diagram of a front wheel reference steering angle provided in an embodiment of this application;

[0032] Figure 7 This is a schematic flowchart of another vehicle steering control method provided in an embodiment of this application;

[0033] Figure 8 This is a schematic flowchart of another vehicle steering control method provided in an embodiment of this application;

[0034] Figure 9 This is a schematic diagram of the structure of a steering control device provided in an embodiment of this application;

[0035] Figure 10 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0036] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0037] To enable vehicles to adapt to road conditions such as narrow roads or obstacle crossings, variable track vehicles are the future development trend. Taking obstacle crossing as an example, the obstacles to be crossed require different track spacing. Therefore, the vehicle's track spacing needs to be adjustable according to the length and size of the obstacle to meet the vehicle's passability requirements.

[0038] Currently, most research focuses on the hardware structure of wheel track adjustment. See also Figure 1 , Figure 1 This is a schematic diagram of the structure of a wheel track adjustment device provided in an embodiment of this application. Figure 1As shown, the wheel track adjustment device includes a wheel track adjustment motor 1, a gear transmission assembly 2, a wheel track adjustment fixed rod 3, a wheel track adjustment sliding rod 4, a lower housing 5, and an upper housing 6. The wheel track adjustment motor 1 provides the power for wheel track adjustment, and its torque output acts on the gear transmission assembly 2. The wheel track adjustment fixed rod 3 is fixed to the gear in the middle, and its two ends have threads with opposite directions of rotation. The wheel track adjustment sliding rod 4 has internal threads, and the thread direction matches that of the wheel track adjustment fixed rod 3. The working principle of the wheel track adjustment device is as follows: When the wheel track adjustment motor 1 rotates forward, the torque is transmitted to the gear transmission assembly 2, driving the wheel track adjustment fixed rod 3 to rotate forward. At this time, due to the opposite direction of rotation of the threads at both ends of the wheel track adjustment fixed rod 3, the wheel track adjustment sliding rod 4 moves in the direction of increasing the wheel track to increase the wheel track; conversely, when the wheel track adjustment motor 1 rotates in reverse, the wheel track adjustment sliding rod 4 moves in the direction of shortening the wheel track to decrease the wheel track. It should be noted that the wheel track adjustment is limited by the maximum and minimum wheel track widths.

[0039] However, variable track width can cause vehicle steering stability issues. Currently, there is relatively little attention paid to the vehicle steering stability problems caused by variable track width.

[0040] See Figure 2 , Figure 2 This is a schematic diagram illustrating a steering scenario for a vehicle with a fixed wheelbase, as described in an embodiment of this application. Figure 2 As shown, in vehicles with a fixed track width, the reference front track width is d. f0 The reference rear track width is d r0 When using the existing vehicle steering control scheme, the intersection point of the extended axle lines of the left and right front wheels and the intersection point of the extended axle lines of the left and right rear wheels are the same point when the vehicle is turning. Figure 2 The axle extensions of all wheels converge at point O (the center of the steering circle), ensuring that each wheel rolls purely with the ground. The reference front track width d is... f0 This refers to the initial front track width of the vehicle at the time of manufacture or the default front track width specified on the vehicle's label. Reference rear track width d r0 This refers to the initial rear track width of the vehicle when it leaves the factory or the default rear track width specified on the vehicle.

[0041] See Figure 3 , Figure 3 This is a schematic diagram illustrating a steering scenario for a vehicle with a variable wheelbase, as described in an embodiment of this application. Figure 3 As shown, in vehicles with variable track widths, the front track width is d. f The rear wheel track is d r Vehicles with adjustable track widths can be those where only the front track width is adjustable, those where only the rear track width is adjustable, or those where both the front and rear track widths are adjustable. Figure 3 In scenarios where only the rear wheel track increases, i.e., d f =d f0 dr =d r0 +∆d r If the existing vehicle steering control scheme is used, when the vehicle is turning, the intersection point O1 of the axle extension lines of the left front wheel and the right front wheel and the intersection point O2 of the axle extension lines of the left rear wheel and the right rear wheel are not the same point, and the distance between the intersection point O1 and the intersection point O2 is large (e.g., greater than 20 centimeters). This will cause the four wheels to slip when turning, and they are prone to sideslip at high speeds, affecting the steering stability and driving safety of the whole vehicle.

[0042] It should be noted that, Figure 3 The diagram only shows a scenario where the rear wheel track increases. In practical applications, there are also scenarios where the rear wheel track decreases, the front wheel track increases, the front wheel track decreases, and the front and rear wheel track decreases or increases simultaneously. In these scenarios, using the existing vehicle steering control scheme, the intersection point O1 of the extended axle lines of the left and right front wheels, and the intersection point O2 of the extended axle lines of the left and right rear wheels, are not the same point, and the distance between intersection points O1 and O2 is relatively large. Therefore, all of these scenarios can cause wheel slippage during steering, making high-speed sideslip more likely and affecting the overall vehicle steering stability and driving safety.

[0043] To prevent sideslip caused by changes in wheel track during vehicle steering, this application provides a vehicle steering control method. This method combines driver input and changes in wheel track to control the wheels to perform pure rolling motion during vehicle steering, reducing the risk of high-speed sideslip, improving steering stability, and reducing tire wear.

[0044] See Figure 4 , Figure 4 This is a schematic flowchart illustrating a vehicle steering control method provided in an embodiment of this application. This method can be applied to vehicles equipped with… Figure 1 The method described herein can also be applied to vehicles equipped with other types of wheel track adjustment devices; this application does not specifically limit its application. The method includes:

[0045] S101: When the vehicle turns, the controller obtains the steering wheel angle of the vehicle.

[0046] The controller, mounted on the vehicle, is used to control the steering of the wheels. For example, the controller can be an electronic steering control unit (steering ECU), which receives steering signals from the steering wheel or other input devices and sends control signals to the steering actuators to drive the wheels in the correct direction.

[0047] The steering wheel angle can be collected by a steering wheel angle sensor installed on the vehicle. Generally, when the absolute value of the steering wheel angle is >5°, it indicates that the vehicle is turning; when the absolute value of the steering wheel angle is ≤5°, it indicates that the vehicle is going straight. This is because during driving, there is slight vibration when the driver holds the steering wheel, and it cannot be guaranteed that the steering wheel angle will always be 0 when the vehicle is going straight.

[0048] S102: If the distance between the left and right front wheels differs from the reference front wheel track, the controller controls the steering angle of the left and right front wheels based on the front wheel track and the steering wheel angle. If the distance between the left and right rear wheels differs from the reference rear wheel track, the controller controls the steering angle of the left and right rear wheels based on the rear wheel track and the steering wheel angle.

[0049] This technical solution is applied to configurations with Figure 1 Taking a vehicle with a wheelbase adjustment device as an example scenario, the method for obtaining real-time changes in wheelbase could be, for example, monitoring... Figure 1 The rotation direction and number of rotations of the wheel track adjustment motor 1 are recorded. If the wheel track adjustment motor 1 rotates in the forward direction, it indicates that the wheel track is increasing; if the wheel track adjustment motor 1 rotates in the reverse direction, it indicates that the wheel track is decreasing. After collecting the number of rotations of the wheel track adjustment motor 1, the wheel track change is determined by converting the change in wheel track based on the unit change in wheel track corresponding to each rotation of the motor (i.e., the change in wheel track per single rotation).

[0050] like Figure 1 The wheel track adjustment device is used to adjust the position of the left or right front wheel. When the number of rotations is 0, the wheel track change is 0, indicating that the front wheel track between the left and right front wheels is the same as the reference front wheel track. When the number of rotations is not 0, the wheel track change is not 0, indicating that the front wheel track between the left and right front wheels is different from the reference front wheel track. Furthermore, if the wheel track adjustment motor 1 rotates in the forward direction, it indicates that the front wheel track increases and is greater than the reference front wheel track; if the wheel track adjustment motor 1 rotates in the reverse direction, it indicates that the front wheel track decreases and is less than the reference front wheel track. The reference front wheel track refers to the initial front wheel track when the vehicle leaves the factory or the default front wheel track specified on the vehicle.

[0051] like Figure 1 The wheel track adjustment device is used to adjust the position of the left or right rear wheel. When the number of rotations is 0, the wheel track change is 0, indicating that the rear wheel track between the left and right rear wheels is the same as the reference rear wheel track. When the number of rotations is not 0, the wheel track change is not 0, indicating that the rear wheel track between the left and right rear wheels is different from the reference rear wheel track. Furthermore, if the wheel track adjustment motor 1 rotates in the forward direction, it indicates that the rear wheel track increases and is greater than the reference rear wheel track; if the wheel track adjustment motor 1 rotates in the reverse direction, it indicates that the rear wheel track decreases and is less than the reference rear wheel track. The reference rear wheel track refers to the initial rear wheel track when the vehicle leaves the factory or the default rear wheel track specified on the vehicle.

[0052] This technical solution is applicable to the following three scenarios:

[0053] Scenario 1: The front wheel track between the left and right front wheels is different from the reference front wheel track, while the rear wheel track between the left and right rear wheels is the same as the reference rear wheel track;

[0054] Scenario 2: The front wheel distance between the left and right front wheels is the same as the reference front wheel distance, but the rear wheel distance between the left and right rear wheels is different from the reference rear wheel distance;

[0055] Scenario 3: The distance between the left and right front wheels is different from the reference front wheel distance, and the distance between the left and right rear wheels is different from the reference rear wheel distance.

[0056] Therefore, the following section will describe the specific implementation process of the steering control method of this application for these three scenarios.

[0057] For scenario one, the steering control method of this application controls the left and right front wheels. Specifically, it is as follows:

[0058] The controller controls the steering angles of the left and right front wheels based on the front track width and steering wheel angle. For example... Figure 5 As shown, the controller specifically performs the following operations:

[0059] S201: The controller determines the front wheel reference angle based on the steering wheel angle.

[0060] The front wheel reference steering angle refers to the angle of deflection of the perpendicular line connecting the first and second points relative to the vehicle's longitudinal axis. It can also be considered the angle between the perpendicular line connecting the first and second points and the vehicle's longitudinal axis. The first point is the midpoint of the line connecting the center of the left and right front wheels, and the second point is the intersection of the extended axle lines of the left and right front wheels. Figure 6 As shown, the midpoint f1 (the first point) of the line connecting the center of the left and right front wheels, the intersection point O1 (the second point) of the extended axle lines of the left and right front wheels, and the angle between the perpendicular line connecting the midpoint f1 and the intersection point O1 and the longitudinal axis of the vehicle. This is the reference steering angle of the front wheel.

[0061] In some embodiments, the controller calculates the front wheel reference steering angle using the following formula:

[0062]

[0063] in, This is the reference steering angle for the front wheels; Steering wheel angle; To improve driving safety and reduce driver reliance on experience, a variable steering ratio is designed based on a constant yaw rate gain. The calculation formula is:

[0064]

[0065] in, The speed of the vehicle; This refers to the vehicle's wheelbase. and These are the minimum and maximum steering ratios, determined based on experience and vehicle parameters, respectively. For a constant yaw rate gain, the yaw rate gain refers to the ratio of the yaw rate to the front wheel steering angle. A fixed yaw rate gain means that the yaw rate gain is a constant value. The value typically ranges from 0.12 to 0.41 s. -1 ; As a stability factor, , For the quality of the vehicle, This is the distance from the midpoint of the line connecting the center of the left and right front wheels to the vehicle's center of gravity. This is the distance from the midpoint of the line connecting the center of the left and right rear wheels to the vehicle's center of gravity. and These are the lateral stiffness of the front and rear wheels, respectively.

[0066] It should be understood that the above method of determining the front wheel reference angle based on the steering wheel angle is merely an example and is not specifically limited in this application.

[0067] S202: The controller determines the rear wheel reference angle based on the front wheel reference angle.

[0068] The rear wheel reference angle refers to the deflection angle of the perpendicular line connecting the third and fourth points relative to the vehicle's longitudinal axis. It can also be considered the angle between the perpendicular line connecting the third and fourth points and the vehicle's longitudinal axis. The third point is the midpoint of the line connecting the center of the left and right rear wheels, and the fourth point is the intersection of the extended axle lines of the left and right rear wheels. Figure 6 As shown, the midpoint f2 (the third point) of the line connecting the center of the left and right rear wheels, the intersection point O2 (the fourth point) of the extended axle lines of the left and right rear wheels, and the angle between the perpendicular line connecting the midpoint f2 and the intersection point O2 and the longitudinal axis of the vehicle. This is the reference steering angle of the rear wheel.

[0069] In some embodiments, the rear wheel reference angle is typically controlled based on parameters such as the front wheel reference angle, vehicle speed, and vehicle dynamics to achieve better steering performance, such as reducing the turning radius and improving handling stability.

[0070] In one specific embodiment, the controller determines the first rear wheel reference angle based on the front wheel reference steering angle, yaw rate, and vehicle speed. The direction of the first rear wheel reference angle is then used as the direction of the rear wheel reference angle, and the minimum value between the absolute values ​​of the front wheel reference angle and the first rear wheel reference angle is taken as the numerical value of the rear wheel reference angle. This limits variable track vehicles to primarily front-wheel steering with rear-wheel auxiliary steering, better aligning with user driving habits. In most vehicles, drivers primarily control the front wheels via the steering wheel, a long-established driving habit. Using the front wheels as the primary steering wheels allows their steering angle to directly reflect the driver's intentions, providing more direct feedback and control, enabling the driver to control the vehicle's direction more intuitively and naturally, reducing learning costs and improving driving comfort. The rear-wheel auxiliary steering optimizes the vehicle's steering characteristics without interfering with driver operation, such as reducing the turning radius and improving stability, thereby enhancing vehicle performance without altering driving habits.

[0071] Specifically, the rear wheel reference steering angle is calculated using the following formula:

[0072]

[0073]

[0074] in, The reference steering angle for the first rear wheel; This is the reference steering angle for the front wheels; For vehicle speed; This refers to the yaw rate; Forward control coefficients , and These are the lateral stiffness of the front and rear wheels, respectively. For yaw rate feedback control gain, , This is the distance from the midpoint of the line connecting the center of the left and right front wheels to the vehicle's center of gravity. This is the distance from the midpoint of the line connecting the center of the left and right rear wheels to the vehicle's center of gravity. For the quality of the vehicle; This is the reference steering angle for the rear wheels; Indicates taking The symbol indicates the rear wheel reference steering angle. relative to the first rear wheel reference angle The directions are the same; This indicates taking the minimum value. This indicates taking the absolute value.

[0075] In another specific embodiment, the controller is based on the front wheel reference steering angle. yaw rate and vehicle speed Calculate the reference steering angle of the first rear wheel Next, set the reference steering angle of the first rear wheel. Directly used as the reference steering angle for the rear wheels This allows the vehicle to maintain good handling stability at both high and low speeds.

[0076] It should be understood that the two methods for determining the rear wheel reference angle from the front wheel reference angle described above are merely examples, and this application does not impose any specific limitations.

[0077] S203: The controller determines the steering direction and value of the left front wheel and the right front wheel based on the front wheel reference steering angle, the rear wheel reference steering angle, and the front wheel track.

[0078] The core of Ackermann steering lies in using a reasonable steering geometry design to ensure that the axle extensions of all wheels converge at the same point (i.e., the steering center) when the vehicle is turning. This guarantees that each wheel rolls purely during the turning process, reduces tire slippage and wear, and improves the vehicle's steering stability and handling.

[0079] To achieve full Ackermann steering, the controller can calculate the corresponding Ackermann angles for the left and right front wheels under a variable front track using the following formula:

[0080]

[0081] in, This refers to the steering direction and value of the left front wheel; This refers to the steering direction and value of the right front wheel; The reference steering angle for the front wheels. The reference steering angle for the rear wheel. This refers to the front track width. This refers to the vehicle's wheelbase.

[0082] The steering angles of the left and right front wheels calculated using the above formula ensure that the steering angles of the rear wheels match those of the front wheels, thus conforming to the Ackermann steering principle.

[0083] Assuming the steering wheel angle is positive when the vehicle turns left, and the wheel angle is positive when the wheels turn left, then the current wheel reference angle... and rear wheel reference angle With the front track fixed and varying compared to the reference front track, while the rear track remains the same as the reference rear track, the variation of the steering angle of each wheel compared to the reference steering angle is shown in Table 1:

[0084] Table 1

[0085]

[0086] In the column for "Left Front Wheel Steering Angle," "Increase" and "Decrease" refer to the comparison between the left front wheel steering angle and the reference left front wheel steering angle. Similarly, in the column for "Right Front Wheel Steering Angle," "Increase" and "Decrease" refer to the comparison between the right front wheel steering angle and the reference right front wheel steering angle. The same applies to the columns for "Left Rear Wheel Steering Angle," "Left Rear Wheel Steering Angle," and "Right Rear Wheel Steering Angle."

[0087] The aforementioned reference steering angles for the left front wheel, right front wheel, left rear wheel, and right rear wheel refer to the steering angles of the left front wheel, right front wheel, left rear wheel, and right rear wheel in response to steering wheel rotation in a vehicle with a fixed track width. In a vehicle with a fixed track width, the reference steering angles for the left and right front wheels are determined based on the reference front track width and steering wheel angle, while the reference steering angles for the left and right rear wheels are determined based on the reference rear track width and steering wheel angle. For the sake of brevity, the following only describes the process of determining the reference steering angles for the left and right front wheels based on the reference front track width and steering wheel angle, as follows:

[0088] For non-steerable-by-wire vehicles, when the driver turns the steering wheel, the steering gear converts rotational motion into linear motion by changing the steering wheel angle. The tie rod then simultaneously pushes or pulls the steering knuckles of both wheels, causing the left and right front wheels to produce corresponding turning angles. The turning angle produced by the left front wheel is the reference turning angle for the left front wheel, and the turning angle produced by the right front wheel is the reference turning angle for the right front wheel. It's understandable that different steering wheel angles will result in different turning angles for the left and right front wheels. On the other hand, different vehicle models have different reference front track widths. Different reference front track widths affect the length of the tie rod and the structure of the steering knuckles. The different lengths of the tie rod or the different structures of the steering knuckles will in turn affect the specific values ​​of the left and right front wheel turning angles at the same steering wheel angle. Therefore, in non-steerable-by-wire vehicles, the reference turning angles of the left and right front wheels are determined by both the reference front track width and the steering wheel angle.

[0089] In steer-by-wire vehicles, when the driver turns the steering wheel, the steering wheel sensor sends a steering wheel angle signal to the control unit. The control unit, combining its internally stored basic steering mapping table and steering actuator motor parameters, determines the target position of the steering actuator motor (usually the lead screw displacement value), and then sends this signal to the steering actuator motor. This drives the steering mechanism to synchronously push or pull the steering knuckles of both wheels, thus causing the left and right front wheels to produce corresponding steering angles. The steering angle produced by the left front wheel is the reference steering angle for the left front wheel, and the steering angle produced by the right front wheel is the reference steering angle for the right front wheel. It can be understood that different steering wheel angles will result in different steering angles for the left and right front wheels. On the other hand, different vehicle models have different reference front track widths. Different reference front track widths affect the structure of the steering knuckles, and different steering knuckle structures will affect the specific values ​​of the left and right front wheel steering angles at the same steering wheel angle. Therefore, in steer-by-wire vehicles, the reference steering angles of the left and right front wheels are determined jointly by the reference front track width and the steering wheel angle.

[0090] For vehicles with rear-wheel steering, the determination of the left and right rear wheel reference steering angles is typically based on the vehicle's real-time state parameters (such as yaw rate, vehicle speed, and steering wheel angle) and its geometric characteristics. In practical applications, the vehicle's controller uses these parameters to look up the corresponding left and right rear wheel reference steering angles from an internally stored steering mapping table. This mapping table is calibrated during the vehicle design phase based on the vehicle's geometry (such as rear track width, wheelbase, and steering system characteristics) to ensure that the rear wheel steering angles match the vehicle's dynamic behavior. It is worth noting that the rear track width, as one of the vehicle's geometric parameters, directly affects the contents of the steering mapping table. Vehicles with different rear track widths will require different rear wheel steering angles under the same steering wheel angle input. Therefore, the left and right rear wheel reference steering angle values ​​stored in the mapping table are adjusted according to the rear track width to ensure that the vehicle can achieve precise steering control under different operating conditions, such as Ackermann steering characteristics, thereby improving the vehicle's steering stability, handling, and driving safety. In summary, the reference steering angles of the left and right rear wheels are determined by the steering wheel angle, real-time vehicle status parameters, and vehicle geometry (such as rear track). The mapping table design fully considers these factors to achieve precise control of rear wheel steering.

[0091] Table 1 shows that the current wheel reference angle and rear wheel reference angle When the front track width is fixed, changes affect the steering angles of the left and right front wheels, causing the steering angle of the left front wheel to change in opposite directions compared to the reference steering angle of the left front wheel, and the steering angle of the right front wheel to change in opposite directions compared to the reference steering angle of the right front wheel. Specifically, if the front track width is greater than the reference front track width, the steering angle of the left front wheel increases compared to the reference steering angle of the left front wheel, while the steering angle of the right front wheel decreases compared to the reference steering angle of the right front wheel. If the front track width is less than the reference front track width, the steering angle of the left front wheel decreases compared to the reference steering angle of the left front wheel, while the steering angle of the right front wheel increases compared to the reference steering angle of the right front wheel.

[0092] S204: The controller controls the steering angle of the left front wheel and the right front wheel based on the steering direction and value of the left front wheel and the steering direction and value of the right front wheel.

[0093] Since the steering angles of the left and right front wheels calculated in step S203 can match the steering angles of the rear wheels with those of the front wheels, which conforms to the Ackermann steering principle, when the controller controls the steering angles of the left and right front wheels based on the steering direction and value of the left and right front wheels, the distance between the intersection point O1 of the axle extension lines of the left and right front wheels and the intersection point O2 of the axle extension lines of the left and right rear wheels is less than or equal to 10 centimeters.

[0094] It should be noted that in practical applications, factors such as actuator accuracy, communication delay, execution delay, and sensor noise can affect the control of the steering angles. For example, errors in real-time wheelbase acquisition, limitations of the actuator's own structure, and communication delays causing delays in the four-wheel steering response may all contribute to the issue. Alternatively, the controller can control the steering angles of the left and right front wheels based on the steering direction and value of the left and right front wheels calculated in step S203, ensuring that the distance between the intersection point O1 of the axle extensions of the left and right front wheels and the intersection point O2 of the axle extensions of the left and right rear wheels is less than or equal to 20 centimeters. This is also the control accuracy range allowed by this application.

[0095] It should be noted that in practical applications of this technical solution, due to the influence of the driving environment, the intersection point O1 of the extended axle lines of the left and right front wheels, and the intersection point O2 of the extended axle lines of the left and right rear wheels, often cannot precisely converge at the same point. Therefore, when the actual distance between intersection points O1 and O2 is within the allowable range (e.g., 10 cm or 20 cm), it can be considered that intersection points O1 and O2 have converged at the same point, and each wheel is in pure rolling motion. In this way, when the vehicle is turning, since each wheel is in pure rolling motion, tire slippage and wear can be effectively reduced, thereby improving the vehicle's steering smoothness and handling stability.

[0096] For scenario two, the steering control method of this application controls the left and right rear wheels. Specifically:

[0097] The controller controls the steering angles of the left and right rear wheels based on the rear track width and steering wheel angle. For example... Figure 7 As shown, the controller specifically performs the following operations:

[0098] S301: The controller determines the front wheel reference angle based on the steering wheel angle.

[0099] The process can be referred to above. Figure 5 The execution process of step S201 will not be described in detail here for the sake of brevity.

[0100] S302: The controller determines the rear wheel reference angle based on the front wheel reference angle.

[0101] The process can be referred to above. Figure 5 The execution process of step S202 will not be described in detail here for the sake of brevity.

[0102] S203: The controller determines the steering direction and value of the left rear wheel and the steering direction and value of the right rear wheel based on the front wheel reference steering angle, the rear wheel reference steering angle, and the rear wheel track.

[0103] The core of Ackermann steering lies in using a reasonable steering geometry design to ensure that the axle extensions of all wheels converge at the same point (i.e., the steering center) when the vehicle is turning. This guarantees that each wheel rolls purely during the turning process, reduces tire slippage and wear, and improves the vehicle's steering stability and handling.

[0104] To achieve full Ackermann steering, the controller can calculate the corresponding Ackermann angles for the left and right rear wheels under variable rear track using the following formula:

[0105]

[0106] in, This refers to the steering direction and value of the left rear wheel. This refers to the steering direction and value of the right rear wheel. The reference steering angle for the front wheels. The reference steering angle for the rear wheel. Rear track width This refers to the vehicle's wheelbase.

[0107] The steering angles of the left and right rear wheels calculated using the above formula ensure that the steering angles of the rear wheels match those of the front wheels, thus conforming to the Ackermann steering principle.

[0108] Assuming the steering wheel angle is positive when the vehicle turns left, and the wheel angle is positive when the wheels turn left, then the current wheel reference angle... and rear wheel reference angle With the front track fixed and the same as the reference front track, the variation of the wheel angles relative to the reference wheel angle when the rear track changes compared to the reference rear track is shown in Table 2:

[0109] Table 2

[0110]

[0111] In the column for "Left Front Wheel Steering Angle," "Increase" and "Decrease" refer to the comparison between the left front wheel steering angle and the reference left front wheel steering angle. Similarly, in the column for "Right Front Wheel Steering Angle," "Increase" and "Decrease" refer to the comparison between the right front wheel steering angle and the reference right front wheel steering angle. The same applies to the columns for "Left Rear Wheel Steering Angle," "Left Rear Wheel Steering Angle," and "Right Rear Wheel Steering Angle."

[0112] Table 2 shows that the current wheel reference angle and rear wheel reference angle When the rear track is fixed, changes in the rear track affect the steering angles of the left and right rear wheels, causing the change in the steering angle of the left rear wheel relative to the reference steering angle of the left rear wheel, and the change in the steering angle of the right rear wheel relative to the reference steering angle of the right rear wheel, to be opposite. Specifically:

[0113] If the rear wheel track is greater than the reference rear wheel track, when the reference steering angle of the front wheel and the reference steering angle of the rear wheel are in the same direction, the steering angle of the left rear wheel is larger than the reference steering angle of the left rear wheel, and the steering angle of the right rear wheel is smaller than the reference steering angle of the right rear wheel; when the reference steering angle of the front wheel and the reference steering angle of the rear wheel are in opposite directions, the steering angle of the left rear wheel is smaller than the reference steering angle of the left rear wheel, and the steering angle of the right rear wheel is larger than the reference steering angle of the right rear wheel.

[0114] If the rear wheel track is less than the reference rear wheel track, when the reference steering angle of the front wheel and the reference steering angle of the rear wheel are in the same direction, the steering angle of the left rear wheel is smaller than the reference steering angle of the left rear wheel, and the steering angle of the right rear wheel is larger than the reference steering angle of the right rear wheel; when the reference steering angle of the front wheel and the reference steering angle of the rear wheel are in opposite directions, the steering angle of the left rear wheel is larger than the reference steering angle of the left rear wheel, and the steering angle of the right rear wheel is smaller than the reference steering angle of the right rear wheel.

[0115] S304: The controller controls the turning angles of the left and right rear wheels based on the turning direction and value of the left and right rear wheels.

[0116] Since the steering angles of the left and right rear wheels calculated in step S303 can match the steering angles of the rear wheels with those of the front wheels, which conforms to the Ackermann steering principle, when the controller controls the steering angles of the left and right rear wheels based on the steering direction and value of the left and right rear wheels, the distance between the intersection point O1 of the axle extension lines of the left and right front wheels and the intersection point O2 of the axle extension lines of the left and right rear wheels is less than or equal to 10 centimeters.

[0117] It should be noted that in practical applications, factors such as actuator accuracy, communication delay, execution delay, and sensor noise can affect the control of the steering angles. For example, errors in real-time wheelbase acquisition, limitations of the actuator's own structure, and communication delays causing delays in the four-wheel steering response may all contribute to the issue. Alternatively, the controller can control the steering angles of the left and right front wheels based on the steering direction and value of the left and right front wheels calculated in step S203, ensuring that the distance between the intersection point O1 of the axle extensions of the left and right front wheels and the intersection point O2 of the axle extensions of the left and right rear wheels is less than or equal to 20 centimeters. This is also the control accuracy range allowed by this application.

[0118] It should be noted that in practical applications of this technical solution, due to the influence of the driving environment, the intersection point O1 of the extended axle lines of the left and right front wheels, and the intersection point O2 of the extended axle lines of the left and right rear wheels, often cannot precisely converge at the same point. Therefore, when the actual distance between intersection points O1 and O2 is within the allowable range (e.g., 10 cm or 20 cm), it can be considered that intersection points O1 and O2 have converged at the same point, and each wheel is in pure rolling motion. In this way, when the vehicle is turning, since each wheel is in pure rolling motion, tire slippage and wear can be effectively reduced, thereby improving the vehicle's steering smoothness and handling stability.

[0119] For scenario three, the steering control method of this application controls the left front wheel, right front wheel, left rear wheel, and right rear wheel. The details are as follows:

[0120] The controller controls the steering angles of the left front wheel, right front wheel, left rear wheel, and right rear wheel based on the front track, rear track, and steering wheel angle. For example... Figure 8 As shown, the controller specifically performs the following operations:

[0121] S401: The controller determines the front wheel reference angle based on the steering wheel angle.

[0122] This process can be referred to as described above. Figure 5 The execution process of step S201 will not be described in detail here for the sake of brevity.

[0123] S402: The controller determines the rear wheel reference angle based on the front wheel reference angle.

[0124] This process can be referred to as described above. Figure 5 The execution process of step S202 will not be described in detail here for the sake of brevity.

[0125] S403: The controller determines the steering direction and value of the left front wheel, the right front wheel, the left rear wheel, and the right rear wheel based on the front wheel reference steering angle, the rear wheel reference steering angle, the front wheel track, and the rear wheel track.

[0126] The core of Ackermann steering lies in using a reasonable steering geometry design to ensure that the axle extensions of all wheels converge at the same point (i.e., the steering center) when the vehicle is turning. This guarantees that each wheel rolls purely during the turning process, reduces tire slippage and wear, and improves the vehicle's steering stability and handling.

[0127] To achieve full Ackerman steering, the controller can calculate the Ackerman angle for each wheel under variable track using the following formula:

[0128]

[0129] in, This refers to the steering direction and value of the left front wheel; This refers to the steering direction and value of the right front wheel; This refers to the steering direction and value of the left rear wheel; This refers to the steering direction and value of the right rear wheel; The reference steering angle for the front wheels. The reference steering angle for the rear wheel. This refers to the front track width. Rear track width This refers to the vehicle's wheelbase.

[0130] The steering angles of the left and right rear wheels calculated using the above formula ensure that the steering angles of the rear wheels match those of the front wheels, thus conforming to the Ackermann steering principle.

[0131] Assuming the steering wheel angle is positive when the vehicle turns left, and the wheel angle is positive when the wheels turn left, then the current wheel reference angle... and rear wheel reference angle When the front track width changes compared to the reference front track width, and the rear track width changes compared to the reference rear track width, the variation of the steering angle of each wheel compared to the reference steering angle is shown in Table 3:

[0132] Table 3

[0133]

[0134] In the column for "Left Front Wheel Steering Angle," "Increase" and "Decrease" refer to the comparison between the left front wheel steering angle and the reference left front wheel steering angle. Similarly, in the column for "Right Front Wheel Steering Angle," "Increase" and "Decrease" refer to the comparison between the right front wheel steering angle and the reference right front wheel steering angle. The same applies to the columns for "Left Rear Wheel Steering Angle," "Left Rear Wheel Steering Angle," and "Right Rear Wheel Steering Angle."

[0135] Table 3 shows that the current wheel reference angle and rear wheel reference angle When fixed, changes in the front track affect the steering angles of the left and right front wheels, causing the steering angle of the left front wheel to change in opposite directions compared to the reference steering angle of the left front wheel, and the steering angle of the right front wheel to change in opposite directions compared to the reference steering angle of the right front wheel. Similarly, changes in the rear track affect the steering angles of the left and right rear wheels, causing the steering angle of the left rear wheel to change in opposite directions compared to the reference steering angle of the left rear wheel, and the steering angle of the right rear wheel to change in opposite directions compared to the reference steering angle of the right rear wheel. Specifically:

[0136] When the reference steering angle of the front wheel and the reference steering angle of the rear wheel are in the same direction, the specifics are as follows:

[0137] If the front wheel track is greater than the reference front wheel track and the rear wheel track is greater than the reference rear wheel track, then the turning angle of the left front wheel is larger than the reference turning angle of the left front wheel, the turning angle of the right front wheel is smaller than the reference turning angle of the right front wheel, the turning angle of the left rear wheel is larger than the reference turning angle of the left rear wheel, and the turning angle of the right rear wheel is smaller than the reference turning angle of the right rear wheel.

[0138] If the front wheel track is the same as the reference front wheel track, and the rear wheel track is greater than the reference rear wheel track, then the turning angle of the left front wheel is the reference turning angle of the left front wheel, the turning angle of the right front wheel is the reference turning angle of the right front wheel, the turning angle of the left rear wheel is larger than the reference turning angle of the left rear wheel, and the turning angle of the right rear wheel is smaller than the reference turning angle of the right rear wheel.

[0139] If the front wheel track is less than the reference front wheel track and the rear wheel track is greater than the reference rear wheel track, then the turning angle of the left front wheel is smaller than the reference turning angle of the left front wheel, the turning angle of the right front wheel is larger than the reference turning angle of the right front wheel, the turning angle of the left rear wheel is larger than the reference turning angle of the left rear wheel, and the turning angle of the right rear wheel is smaller than the reference turning angle of the right rear wheel.

[0140] If the front wheel track is greater than the reference front wheel track and the rear wheel track is less than the reference rear wheel track, then the turning angle of the left front wheel is larger than the reference turning angle of the left front wheel, the turning angle of the right front wheel is smaller than the reference turning angle of the right front wheel, the turning angle of the left rear wheel is smaller than the reference turning angle of the left rear wheel, and the turning angle of the right rear wheel is larger than the reference turning angle of the right rear wheel.

[0141] If the front wheel track is the same as the reference front wheel track, and the rear wheel track is greater than the reference rear wheel track, then the turning angle of the left front wheel is the reference turning angle of the left front wheel, the turning angle of the right front wheel is the reference turning angle of the right front wheel, the turning angle of the left rear wheel is smaller than the reference turning angle of the left rear wheel, and the turning angle of the right rear wheel is larger than the reference turning angle of the right rear wheel.

[0142] If the front wheel track is less than the reference front wheel track and the rear wheel track is greater than the reference rear wheel track, then the turning angle of the left front wheel is smaller than the reference turning angle of the left front wheel, the turning angle of the right front wheel is larger than the reference turning angle of the right front wheel, the turning angle of the left rear wheel is smaller than the reference turning angle of the left rear wheel, and the turning angle of the right rear wheel is larger than the reference turning angle of the right rear wheel.

[0143] When the reference steering angles of the front and rear wheels are in different directions, the specifics are as follows:

[0144] If the front wheel track is greater than the reference front wheel track and the rear wheel track is greater than the reference rear wheel track, then the turning angle of the left front wheel is greater than the reference turning angle of the left front wheel, the turning angle of the right front wheel is less than the reference turning angle of the right front wheel, the turning angle of the left rear wheel is less than the reference turning angle of the left rear wheel, and the turning angle of the right rear wheel is greater than the reference turning angle of the right rear wheel.

[0145] If the front wheel track is the same as the reference front wheel track, and the rear wheel track is greater than the reference rear wheel track, then the turning angle of the left front wheel is the reference turning angle of the left front wheel, the turning angle of the right front wheel is the reference turning angle of the right front wheel, the turning angle of the left rear wheel is smaller than the reference turning angle of the left rear wheel, and the turning angle of the right rear wheel is larger than the reference turning angle of the right rear wheel.

[0146] If the front wheel track is less than the reference front wheel track and the rear wheel track is greater than the reference rear wheel track, then the turning angle of the left front wheel is smaller than the reference turning angle of the left front wheel, the turning angle of the right front wheel is larger than the reference turning angle of the right front wheel, the turning angle of the left rear wheel is smaller than the reference turning angle of the left rear wheel, and the turning angle of the right rear wheel is larger than the reference turning angle of the right rear wheel.

[0147] If the front wheel track is greater than the reference front wheel track and the rear wheel track is less than the reference rear wheel track, then the turning angle of the left front wheel is larger than the reference turning angle of the left front wheel, the turning angle of the right front wheel is smaller than the reference turning angle of the right front wheel, the turning angle of the left rear wheel is larger than the reference turning angle of the left rear wheel, and the turning angle of the right rear wheel is smaller than the reference turning angle of the right rear wheel.

[0148] If the front wheel track is the same as the reference front wheel track, and the rear wheel track is greater than the reference rear wheel track, then the turning angle of the left front wheel is the reference turning angle of the left front wheel, the turning angle of the right front wheel is the reference turning angle of the right front wheel, the turning angle of the left rear wheel is larger than the reference turning angle of the left rear wheel, and the turning angle of the right rear wheel is smaller than the reference turning angle of the right rear wheel.

[0149] If the front wheel track is less than the reference front wheel track and the rear wheel track is greater than the reference rear wheel track, then the turning angle of the left front wheel is smaller than the reference turning angle of the left front wheel, the turning angle of the right front wheel is larger than the reference turning angle of the right front wheel, the turning angle of the left rear wheel is larger than the reference turning angle of the left rear wheel, and the turning angle of the right rear wheel is smaller than the reference turning angle of the right rear wheel.

[0150] S404: The controller controls the steering angles of the left front wheel, right front wheel, left rear wheel, and right rear wheel based on the steering direction and value of the left front wheel, right front wheel, left rear wheel, and right rear wheel.

[0151] Since the steering angles of each wheel calculated in step S403 can match the steering angles of the rear wheels with those of the front wheels, which conforms to the Ackermann steering principle, when the controller controls the steering angles of the left front wheel, right front wheel, left rear wheel, and right rear wheel based on the steering angle direction and value of the left front wheel, right front wheel, left rear wheel, and right rear wheel, the distance between the intersection point O1 of the axle extension lines of the left and right front wheels and the intersection point O2 of the axle extension lines of the left and right rear wheels is less than or equal to 10 centimeters.

[0152] It should be noted that in practical applications, factors such as actuator accuracy, communication delay, execution delay, and sensor noise can affect the control of the steering angles. For example, errors in real-time wheelbase acquisition, limitations of the actuator's own structure, and communication delays causing delays in the four-wheel steering response may all contribute to the issue. Alternatively, the controller can control the steering angles of the left and right front wheels based on the steering direction and value of the left and right front wheels calculated in step S203, ensuring that the distance between the intersection point O1 of the axle extensions of the left and right front wheels and the intersection point O2 of the axle extensions of the left and right rear wheels is less than or equal to 20 centimeters. This is also the control accuracy range allowed by this application.

[0153] It should be noted that in practical applications of this technical solution, due to the influence of the driving environment, the intersection point O1 of the extended axle lines of the left and right front wheels, and the intersection point O2 of the extended axle lines of the left and right rear wheels, often cannot precisely converge at the same point. Therefore, when the actual distance between intersection points O1 and O2 is within the allowable range (e.g., 10 cm or 20 cm), it can be considered that intersection points O1 and O2 have converged at the same point, and each wheel is in pure rolling motion. In this way, when the vehicle is turning, since each wheel is in pure rolling motion, tire slippage and wear can be effectively reduced, thereby improving the vehicle's steering smoothness and handling stability.

[0154] In summary, the vehicle steering control method provided in this application, by combining driver input (corresponding to changes in steering wheel angle) and track width changes to control the wheels to perform pure rolling motion during vehicle steering, can enhance vehicle steering stability, reduce the risk of sideslip, reduce tire wear, and improve driving safety performance. It is particularly suitable for dangerous situations such as needing to adjust track width when encountering obstacles on a turning road. Furthermore, this steering control method can be applied to vehicles with adjustable front track width only, vehicles with adjustable rear track width only, and vehicles with adjustable track widths for both the front and rear wheels, demonstrating a wide range of applicability and supporting diverse scenarios.

[0155] See Figure 9 , Figure 9 This is a schematic diagram of a steering control device provided in an embodiment of this application. The control device is used to achieve the aforementioned... Figure 4 Steering control methods for vehicles. For example... Figure 9 As shown, the steering control device 500 includes an acquisition module 501 and a control module 502.

[0156] The acquisition module 501 is used to acquire the steering wheel angle of the vehicle when the vehicle is turning.

[0157] The control module 502 is used to control the steering angle of the left front wheel and the right front wheel based on the front wheel track and steering wheel angle when the front wheel track between the left and right front wheels of the vehicle differs from the reference front wheel track. And / or, the control module 502 is used to control the steering angle of the left rear wheel and the right rear wheel based on the rear wheel track and steering wheel angle when the rear wheel track between the left and right rear wheels of the vehicle differs from the reference rear wheel track, so that the distance between the intersection point of the axle extension lines of the left and right front wheels and the intersection point of the axle extension lines of the left and right rear wheels is less than or equal to 20 centimeters.

[0158] Optionally, the control module 502 is specifically used to: determine the front wheel reference angle based on the steering wheel angle; determine the rear wheel reference angle based on the front wheel reference angle; determine the steering direction and value of the left front wheel and the right front wheel based on the front wheel reference angle, the rear wheel reference angle, and the front wheel track; and control the steering angles of the left and right front wheels based on the steering direction and value of the left and right front wheels.

[0159] Optionally, the control module 502 is specifically used to: calculate the steering direction and value of the left front wheel and the steering direction and value of the right front wheel using the following formulas:

[0160]

[0161] in, This refers to the steering direction and value of the left front wheel. This refers to the steering direction and value of the right front wheel. The reference steering angle for the front wheels. The reference steering angle for the rear wheel. This refers to the front track width. This refers to the vehicle's wheelbase.

[0162] Optionally, the change in the steering angle of the left front wheel relative to the reference steering angle of the left front wheel is opposite to the change in the steering angle of the right front wheel relative to the reference steering angle of the right front wheel. Both the reference steering angle of the left front wheel and the reference steering angle of the right front wheel are determined based on the reference front track and steering wheel angle.

[0163] Optionally, if the front wheel track is greater than the reference front wheel track, the steering angle of the left front wheel is increased compared to the reference steering angle of the left front wheel, and the steering angle of the right front wheel is decreased compared to the reference steering angle of the right front wheel. If the front wheel track is less than the reference front wheel track, the steering angle of the left front wheel is decreased compared to the reference steering angle of the left front wheel, and the steering angle of the right front wheel is increased compared to the reference steering angle of the right front wheel.

[0164] Optionally, the control module 502 is specifically used to: determine the front wheel reference angle based on the steering wheel angle; determine the rear wheel reference angle based on the front wheel reference angle; determine the direction and value of the left rear wheel's angle and the right rear wheel's angle based on the front wheel reference angle, the rear wheel reference angle, and the rear track; and control the angles of the left and right rear wheels based on the direction and value of the left and right rear wheels' angles.

[0165] Optionally, the control module 502 is specifically used to: calculate the steering direction and value of the left rear wheel and the steering direction and value of the right rear wheel using the following formulas:

[0166]

[0167] in, This refers to the steering direction and value of the left rear wheel. This refers to the steering direction and value of the right rear wheel. The reference steering angle for the front wheels. The reference steering angle for the rear wheel. Rear track width This refers to the vehicle's wheelbase.

[0168] Optionally, the change in the steering angle of the left rear wheel relative to the reference steering angle of the left rear wheel is opposite to the change in the steering angle of the right rear wheel relative to the reference steering angle of the right rear wheel. Both the reference steering angles of the left and right rear wheels are determined based on the reference rear track and the steering wheel angle.

[0169] Optionally, if the rear wheel track is greater than the reference rear wheel track, when the reference steering angle of the front wheel and the reference steering angle of the rear wheel are in the same direction, the steering angle of the left rear wheel is larger than the reference steering angle of the left rear wheel, and the steering angle of the right rear wheel is smaller than the reference steering angle of the right rear wheel; when the reference steering angle of the front wheel and the reference steering angle of the rear wheel are in opposite directions, the steering angle of the left rear wheel is smaller than the reference steering angle of the left rear wheel, and the steering angle of the right rear wheel is larger than the reference steering angle of the right rear wheel. If the rear wheel track is less than the reference rear wheel track, when the reference steering angle of the front wheel and the reference steering angle of the rear wheel are in the same direction, the steering angle of the left rear wheel is smaller than the reference steering angle of the left rear wheel, and the steering angle of the right rear wheel is larger than the reference steering angle of the right rear wheel; when the reference steering angle of the front wheel and the reference steering angle of the rear wheel are in opposite directions, the steering angle of the left rear wheel is larger than the reference steering angle of the left rear wheel, and the steering angle of the right rear wheel is smaller than the reference steering angle of the right rear wheel.

[0170] Optionally, if the rear wheel track is greater than or less than the reference rear wheel track, and the reference steering angle of the front wheel is in the same direction or different from the reference steering angle of the rear wheel, if the front wheel track is greater than the reference front wheel track, the steering angle of the left front wheel is larger than the reference steering angle of the left front wheel, and the steering angle of the right front wheel is smaller than the reference steering angle of the right front wheel; if the front wheel track is the same as the reference front wheel track, the steering angle of the left front wheel is the reference steering angle of the left front wheel, and the steering angle of the right front wheel is the reference steering angle of the right front wheel; if the front wheel track is less than the reference front wheel track, the steering angle of the left front wheel is smaller than the reference steering angle of the left front wheel, and the steering angle of the right front wheel is larger than the reference steering angle of the right front wheel.

[0171] Optionally, the direction of the rear wheel reference angle is the same as the direction of the first rear wheel reference angle. The value of the rear wheel reference angle is the minimum of the absolute values ​​of the front wheel reference angle and the first rear wheel reference angle. The first rear wheel reference angle is determined based on the front wheel reference angle, yaw rate, and vehicle speed.

[0172] Optionally, the distance between the intersection of the axle extensions of the left and right front wheels and the intersection of the axle extensions of the left and right rear wheels is less than or equal to 10 centimeters.

[0173] Each module in the aforementioned steering control device 500 can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in hardware within or independently of the processor in the control device, or stored in software within the memory of an electronic device, so that the processor can call and execute the operations corresponding to each module.

[0174] See Figure 10 , Figure 10 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. For example... Figure 10As shown, the electronic device 600 includes a processor 601 and a memory 603. The processor 601 and the memory 603 are connected, for example, via a bus 602. Optionally, the electronic device 600 may also include a transceiver 604. It should be noted that in practical applications, the transceiver 604 is not limited to one type, and the structure of this electronic device 600 does not constitute a limitation on the embodiments of this application.

[0175] Processor 601 may be a central processing unit (CPU), a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It can implement or execute the various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this application. Processor 601 may also be a combination that implements computational functions, such as including one or more microprocessor combinations, a combination of a DSP and a microprocessor, etc.

[0176] Bus 602 may include a pathway for transmitting information between the aforementioned components. Bus 602 may be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. Bus 602 may be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 10 The symbol is represented by only one line, but this does not mean that there is only one bus or one type of bus.

[0177] The memory 603 stores a computer program corresponding to the control method of the above embodiments of this application, which is executed by the processor 601. The processor 601 executes the computer program stored in the memory 603 to implement the content shown in the aforementioned user reminder method embodiments.

[0178] The electronic device 600 may be, for example, a controller, which is not specifically limited in this application. Figure 10 The electronic device 600 shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of this application.

[0179] This application also provides a computer program product or computer program, which includes computer instructions stored in a computer-readable storage medium. The processor of an electronic device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the electronic device to perform the vehicle steering control method provided in the various optional implementations of the above embodiments.

[0180] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be performed by a computer program, or by a computer program controlling related hardware. The computer program can be stored in a computer-readable storage medium and loaded and executed by a processor.

[0181] This application also provides a computer-readable storage medium storing instructions that, when executed by a processor, configure the processor to perform the aforementioned vehicle steering control. The computer-readable storage medium may include: read-only memory (ROM), random access memory (RAM), a magnetic disk, or an optical disk, etc.

[0182] In the description of this application, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0183] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0184] The embodiments, implementation methods, and related technical features of this application can be combined and substituted for each other without conflict.

[0185] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A vehicle steering control method, characterized in that, The vehicle includes a steering wheel, a left front wheel, a right front wheel, a left rear wheel, and a right rear wheel; the method includes: When the vehicle turns, the steering wheel angle is obtained; If the distance between the left and right front wheels differs from the reference front wheel distance, the steering angles of the left and right front wheels are controlled based on the front wheel distance and the steering wheel angle, and / or... If the rear wheel distance between the left and right rear wheels is different from the reference rear wheel distance, the steering angle of the left and right rear wheels is controlled based on the rear wheel distance and the steering wheel angle, so that the distance between the intersection point of the axle extension lines of the left and right front wheels and the intersection point of the axle extension lines of the left and right rear wheels is less than or equal to 20 centimeters.

2. The method according to claim 1, characterized in that, The method of controlling the steering angle of the left front wheel and the right front wheel based on the front wheel track and the steering wheel angle includes: The front wheel reference angle is determined based on the steering wheel angle. The rear wheel reference angle is determined based on the aforementioned front wheel reference angle. Based on the front wheel reference angle, the rear wheel reference angle, and the front wheel track, determine the steering direction and value of the left front wheel, and determine the steering direction and value of the right front wheel; Based on the steering direction and value of the left front wheel, and the steering direction and value of the right front wheel, the steering angles of the left front wheel and the right front wheel are controlled.

3. The method according to claim 2, characterized in that, The process of determining the direction and value of the left front wheel's steering angle and the direction and value of the right front wheel's steering angle based on the front wheel reference steering angle, the rear wheel reference steering angle, and the front track includes: The steering direction and value of the left front wheel and the steering direction and value of the right front wheel are calculated using the following formulas: in, The direction and value of the steering angle of the left front wheel. The direction and value of the steering angle of the right front wheel. The reference steering angle of the front wheel is... The rear wheel reference angle is... The front track width is... The wheelbase of the vehicle is given.

4. The method according to any one of claims 1-3, characterized in that, The change in the steering angle of the left front wheel compared to the reference steering angle of the left front wheel is opposite to the change in the steering angle of the right front wheel compared to the reference steering angle of the right front wheel. The reference steering angles of the left front wheel and the left front wheel are both determined based on the reference front track and the steering wheel angle.

5. The method according to claim 4, characterized in that, If the front wheel track is greater than the reference front wheel track, the steering angle of the left front wheel is increased compared to the reference steering angle of the left front wheel, and the steering angle of the right front wheel is decreased compared to the reference steering angle of the right front wheel; If the front wheel track is less than the reference front wheel track, the steering angle of the left front wheel is smaller than the reference steering angle of the left front wheel, and the steering angle of the right front wheel is larger than the reference steering angle of the right front wheel.

6. The method according to claim 1, 2, 3 or 5, characterized in that, The method of controlling the steering angle of the left rear wheel and the right rear wheel based on the rear track and the steering wheel angle includes: The front wheel reference angle is determined based on the steering wheel angle. The rear wheel reference angle is determined based on the aforementioned front wheel reference angle. Based on the front wheel reference angle, the rear wheel reference angle, and the rear wheel track, determine the steering direction and value of the left rear wheel, and determine the steering direction and value of the right rear wheel; Based on the steering direction and value of the left rear wheel and the steering direction and value of the right rear wheel, the steering angles of the left rear wheel and the right rear wheel are controlled.

7. The method according to claim 6, characterized in that, The determination of the steering direction and value of the left rear wheel and the steering direction and value of the right rear wheel based on the front wheel reference steering angle, the rear wheel reference steering angle, and the rear track includes: The steering direction and value of the left rear wheel and the steering direction and value of the right rear wheel are calculated using the following formulas: in, The direction and value of the steering angle of the left rear wheel. The direction and value of the steering angle of the right rear wheel. The reference steering angle of the front wheel is... The rear wheel reference angle is... The rear track width is... The wheelbase of the vehicle is given.

8. The method according to claim 7, characterized in that, The change in the steering angle of the left rear wheel compared to the reference steering angle of the left rear wheel is opposite to the change in the steering angle of the right rear wheel compared to the reference steering angle of the right rear wheel. The reference steering angles of the left and right rear wheels are both determined based on the reference rear track and the steering wheel angle.

9. The method according to claim 8, characterized in that, If the rear wheel track is greater than the reference rear wheel track, when the reference steering angle of the front wheel and the reference steering angle of the rear wheel are in the same direction, the steering angle of the left rear wheel is larger than the reference steering angle of the left rear wheel, and the steering angle of the right rear wheel is smaller than the reference steering angle of the right rear wheel; when the reference steering angle of the front wheel and the reference steering angle of the rear wheel are in opposite directions, the steering angle of the left rear wheel is smaller than the reference steering angle of the left rear wheel, and the steering angle of the right rear wheel is larger than the reference steering angle of the right rear wheel. If the rear wheel track is less than the reference rear wheel track, when the reference steering angle of the front wheel and the reference steering angle of the rear wheel are in the same direction, the steering angle of the left rear wheel is smaller than the reference steering angle of the left rear wheel, and the steering angle of the right rear wheel is larger than the reference steering angle of the right rear wheel; when the reference steering angle of the front wheel and the reference steering angle of the rear wheel are in opposite directions, the steering angle of the left rear wheel is larger than the reference steering angle of the left rear wheel, and the steering angle of the right rear wheel is smaller than the reference steering angle of the right rear wheel.

10. The method according to claim 9, characterized in that, If the rear wheel track is greater than or less than the reference rear wheel track, and the reference front wheel steering angle and the reference rear wheel steering angle are in the same or different directions... If the front wheel track is greater than the reference front wheel track, the steering angle of the left front wheel is increased compared to the reference steering angle of the left front wheel, and the steering angle of the right front wheel is decreased compared to the reference steering angle of the right front wheel; If the front wheel track is the same as the reference front wheel track, the turning angle of the left front wheel is the reference turning angle of the left front wheel, and the turning angle of the right front wheel is the reference turning angle of the right front wheel; If the front wheel track is less than the reference front wheel track, the steering angle of the left front wheel is smaller than the reference steering angle of the left front wheel, and the steering angle of the right front wheel is larger than the reference steering angle of the right front wheel.

11. The method according to claim 2 or 6, characterized in that, The direction of the rear wheel reference angle is the direction of the first rear wheel reference angle; The value of the rear wheel reference angle is the minimum value between the absolute value of the front wheel reference angle and the absolute value of the first rear wheel reference angle. The first rear wheel reference steering angle is determined based on the front wheel reference steering angle, yaw rate, and vehicle speed.

12. The method according to any one of claims 1, 2, 3, 5, 7, 8, 9, and 10, characterized in that, The distance between the intersection of the axle extensions of the left front wheel and the right front wheel and the intersection of the axle extensions of the left rear wheel and the right rear wheel is less than or equal to 10 centimeters.

13. An electronic device, characterized in that, include: A memory on which computer programs are stored; A processor for executing the computer program in the memory to implement the vehicle steering control method according to any one of claims 1 to 12.

14. A vehicle, characterized in that, It includes a wheel track adjustment device and the electronic device as described in claim 13.

15. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the vehicle steering control method according to any one of claims 1 to 12.

Images