Wheel turning angle control method and device, storage medium and equipment

Abstract

The invention provides a wheel turning angle control method and device, a storage medium and equipment, in the method, for a vehicle with a distributed steer-by-wire system, the average turning angle of wheels is calculated according to the turning angle of a steering wheel, and the target turning angles of left and right wheels are calculated in combination with the ideal turning angle relation of inner and outer wheels and an Ackerman rate calculation formula; the actual execution turning angle of the wheel is verified based on the calculated target turning angle, if verification fails and the wheel cannot execute towards the target turning angle, it is indicated that the wheel turns unexpectedly, and the target turning angle of the wheel on the other side is adjusted based on the actual execution turning angle of the wheel, so that the turning angles of the left wheel and the right wheel are coordinated. Therefore, when the vehicle is subjected to unexpected impact, the left wheel and the right wheel can quickly respond and coordinate and match, so that the situation that the vehicle is unstable due to impact of a single wheel is effectively avoided.

Description

Technical Field

[0001] This application relates to the field of automotive control technology, and more specifically, to a wheel steering angle control method, device, storage medium, and equipment. Background Technology

[0002] With the development of automotive technology, vehicles are showing a trend towards automation and modularization. The corner module, as the core execution unit of the steer-by-wire integrated chassis, is becoming an important development direction. The corner module employs distributed steer-by-wire, which decouples the left and right wheels, allowing for independent control of each wheel, greatly expanding the vehicle's application scenarios.

[0003] However, due to the structure of the left and right wheels, when a vehicle is subjected to a single-wheel impact, the impact of that single wheel cannot be transmitted synchronously through the mechanical system. The coordination between the left and right wheels is easily disrupted, causing the vehicle to steer unexpectedly and thus easily lose control. Summary of the Invention

[0004] The purpose of this application is to provide a wheel steering angle control method, device, storage medium and equipment, which aims to solve the problem that vehicles with distributed steer-by-wire are prone to loss of control when faced with a single wheel impact in related technologies.

[0005] In a first aspect, this application provides a wheel angle control method applied to the controller of a distributed steer-by-wire system; the method includes: calculating the average wheel angle based on the steering wheel angle, and then calculating the target angles of the left and right wheels based on the average wheel angle using a wheel target angle algorithm; the average wheel angle is the average of the inner wheel angle and the outer wheel angle; the wheel target angle algorithm is obtained based on the ideal angle relationship between the inner and outer wheels and the Ackerman ratio calculation formula; verifying the actual executed angle of the wheel based on the target angle of either the left or right wheel; when the actual executed angle verification fails and the wheel cannot execute the target angle, adjusting the target angle of the other wheel based on the actual executed angle and the wheel target angle algorithm.

[0006] In the above implementation process, for vehicles with a distributed steer-by-wire system, the average wheel angle is calculated based on the steering wheel angle. Combining the ideal steering angle relationship between the inner and outer wheels and the Ackerman ratio formula, the target steering angles for the left and right wheels are calculated. The actual steering angles of the wheels are then verified based on the calculated target angles. If the verification fails and the wheel cannot achieve the target steering angle, it indicates that the wheel is steering unexpectedly. In this way, the target steering angle of the other wheel is adjusted based on the actual steering angle of that wheel, ensuring coordinated steering between the left and right wheels. Thus, when the vehicle experiences an unexpected impact, the left and right wheels can respond quickly and coordinate effectively, thereby preventing vehicle instability caused by impacts from a single wheel.

[0007] Furthermore, in some examples, the calculation of the average wheel angle based on the steering wheel angle includes: calculating the angular transmission ratio based on the vehicle speed and yaw rate; and calculating the average wheel angle based on the current steering wheel angle and the angular transmission ratio.

[0008] In the above implementation process, a specific method is provided for calculating the average wheel turning angle based on the steering wheel turning angle.

[0009] Furthermore, in some examples, the step of calculating the target turning angles of the left and right wheels using a target turning angle algorithm based on the average turning angle of the wheels includes: establishing a first equation based on the average turning angle of the wheels; the unknowns of the first equation include the inner wheel turning angle and the outer wheel turning angle; establishing a second equation based on the ideal turning angle relationship between the inner and outer wheels; the unknowns of the second equation include the inner wheel turning angle and the ideal turning angle of the outer wheel; establishing a third equation based on the Ackermann ratio calculation formula; the unknowns of the third equation include the inner wheel turning angle, the outer wheel turning angle, and the ideal turning angle of the outer wheel; solving the system of equations consisting of the first equation, the second equation, and the third equation; and determining the target turning angles of the left and right wheels based on the solution results.

[0010] In the above implementation process, based on the average wheel turning angle, the ideal turning angle relationship between the inner and outer wheels, and the Ackerman ratio calculation formula, a set of three equations is established. Solving this set of equations allows for the rapid and accurate determination of the target turning angles of the left and right wheels.

[0011] Furthermore, in some examples, the step of verifying the actual turning angle of the wheel based on the target turning angle of either the left wheel or the right wheel includes: calculating the difference between the target turning angle and the actual turning angle of either the left wheel or the right wheel; if the absolute value of the difference is less than or equal to a target threshold, the verification is determined to pass; if the absolute value of the difference is greater than the target threshold, the verification is determined to fail.

[0012] In the above implementation process, an angle verification method is provided, which compares the difference between the target turning angle of the wheel and the actual turning angle and the target threshold, and determines whether the actual turning angle of the wheel meets the expectations based on the comparison result.

[0013] Furthermore, in some examples, it also includes: when the actual angle of the wheel fails the verification, and the wheel can perform the turn towards the target angle, controlling the wheel to continue performing the turn towards the target angle until the absolute value of the difference between the target angle and the actual angle of the wheel is less than or equal to the target threshold.

[0014] In the above implementation process, if the actual steering angle verification of a wheel fails, but the wheel can still achieve the target steering angle, it indicates that the wheel has overshooted or is not performing correctly. In this case, the wheel is controlled to execute the expected angle until the verification passes. This ensures that the vehicle wheel steering angle meets the expected requirements and satisfies the vehicle dynamics requirements.

[0015] Furthermore, in some examples, the algorithm for adjusting the target angle of the other wheel based on the actual executed turning angle of the wheel and the target turning angle of the wheel includes: if the wheel is the inner wheel, substituting the actual executed turning angle of the wheel as the inner wheel turning angle into the system of equations to solve for the outer wheel turning angle, and adjusting the target turning angle of the other wheel to the outer wheel turning angle; if the wheel is the outer wheel, substituting the actual executed turning angle of the wheel as the outer wheel turning angle into the system of equations to solve for the inner wheel turning angle, and adjusting the target turning angle of the other wheel to the inner wheel turning angle.

[0016] In the above implementation process, when the inner wheel fails the verification and cannot turn towards the target angle, its actual turning angle is substituted into the previously established equations as the inner wheel turning angle. Then, based on the recalculated outer wheel turning angle, the target turning angle of the other wheel is adjusted. Similarly, when the outer wheel fails the verification and cannot turn towards the target angle, its actual turning angle is substituted into the previously established equations as the outer wheel turning angle. Then, based on the recalculated inner wheel turning angle, the target turning angle of the other wheel is adjusted. In this way, when the vehicle is subjected to an unexpected impact, the left and right wheels can respond quickly and coordinate effectively.

[0017] Furthermore, in some examples, it also includes: when adjusting the target turning angle of the wheels, adjusting the steering wheel angle according to the current target turning angles of the left and right wheels and the overall vehicle speed, so that the position of the steering wheel matches the turning angle of the wheels.

[0018] In the above implementation process, when the vehicle turns unexpectedly, the steer-by-wire controller adjusts the target turning angle of the wheels to coordinate the turning angles of the left and right wheels. At the same time, based on the adjusted target turning angle of the wheels and the vehicle speed, the steering wheel angle is adjusted to match the position of the wheels, thereby providing accurate and effective feedback to the driver and ensuring driving safety.

[0019] Furthermore, in some examples, it also includes: when the vehicle is braking or accelerating on a straight road, if the steering wheel angle is zero and the yaw rate is not zero, the PID control algorithm is used to calculate the angle compensation value with the goal of controlling the yaw rate to be zero, and the target steering angle is adjusted based on the angle compensation value.

[0020] In the above implementation process, when the vehicle brakes or accelerates on a straight road, if the steering wheel angle is 0 and the yaw rate is not 0, it is determined that the vehicle is veering off course. At this time, the PID control algorithm is used to control the yaw rate to be 0 as the target and to give an angle compensation value to one side of the vehicle's wheels. In this way, by superimposing the compensation value brought by the yaw response of the whole vehicle, the vehicle direction can be accurately and effectively corrected.

[0021] Furthermore, in some examples, it also includes: when the vehicle is driving on a curve, if the lateral acceleration of the vehicle exceeds a preset threshold, or the wheel speeds of the four wheels do not operate as expected, a PID control algorithm is used to control the lateral acceleration as the target acceleration value or the wheel speeds of the four wheels as the target wheel speed value, and reduce the target turning angle of the outer wheels.

[0022] In the above implementation process, when the vehicle is driving on a curve, if it is detected that the lateral acceleration of the vehicle exceeds the preset threshold or the speed of the four wheels does not operate as expected, it indicates that the vehicle has a tendency to become unstable. At this time, the PID control algorithm is used to control the lateral acceleration of the vehicle or the speed of the four wheels, thereby reducing the turning angle of the outer wheels and improving the understeer of the vehicle, thus improving the stability of the vehicle.

[0023] Secondly, this application provides a wheel angle control device applied to the controller of a distributed steer-by-wire system; the device includes: a calculation module, used to calculate the average wheel angle based on the steering wheel angle, and then calculate the target angles of the left and right wheels based on the average wheel angle using a wheel target angle algorithm; the average wheel angle is the average of the inner wheel angle and the outer wheel angle; the wheel target angle algorithm is obtained based on the ideal angle relationship between the inner and outer wheels and the Ackerman ratio calculation formula; a verification module, used to verify the actual executed angle of the wheel based on the target angle of either the left or right wheel; and an adjustment module, used to adjust the target angle of the other wheel based on the actual executed angle of the wheel and the wheel target angle algorithm when the actual executed angle verification fails and the wheel cannot execute the target angle.

[0024] Thirdly, this application provides an electronic device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the steps of the method described in any of the first aspects.

[0025] Fourthly, this application provides a computer-readable storage medium storing instructions that, when executed on a computer, cause the computer to perform the method described in any of the first aspects.

[0026] Fifthly, this application provides a computer program product that, when run on a computer, causes the computer to perform the method described in any of the first aspects.

[0027] Other features and advantages disclosed in this application will be set forth in the following description, or some features and advantages may be inferred from the description or determined without doubt, or may be learned by practicing the above-described technology disclosed in this application.

[0028] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 A schematic diagram of the structure of a corner module provided in an embodiment of this application; Figure 2 A flowchart of a wheel steering angle control method provided in an embodiment of this application; Figure 3 This is a schematic diagram of the structure of a distributed steer-by-wire system provided in an embodiment of this application; Figure 4 A schematic diagram of a variable transmission ratio design provided in an embodiment of this application; Figure 5 A schematic diagram illustrating the workflow of a distributed steer-by-wire wheel angle control scheme provided in an embodiment of this application; Figure 6 A block diagram of a wheel steering angle control device provided in an embodiment of this application; Figure 7 This is a structural block diagram of an electronic device provided in an embodiment of this application. Detailed Implementation

[0031] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0032] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0033] With the development of automotive technology, the chassis, as the main execution platform for realizing intelligent driving, is constantly evolving towards mechatronics integration, control integration, and intelligent electrification. The corner module, as the core technology hub of the drive-by-wire integrated chassis, is driving the intelligent transformation of the chassis system. The structure of the corner module is as follows: Figure 1 As shown, it is connected to the vehicle via the upper control arm 101, the lower control arm 102 and the shock absorber 106. The corner module uses drive-by-wire technology to achieve independent control of the wheels and tires 107 through the internally integrated steering system 103, drive system 104 and braking system 105.

[0034] In the corner module, distributed steer-by-wire is employed. The steering gear housing is connected to the upper control arm 101, and the lower end of the steering gear is connected to the steering knuckle, directly driving the steering knuckle to steer. Distributed steer-by-wire decouples the left and right wheels, allowing independent control of each wheel, greatly expanding the vehicle's application scenarios. For example, reversing the left and right wheels enables a true U-turn on the spot; turning all four wheels 90° enables lateral translation; and turning each of the four wheels 45° enables a U-turn on the spot without tire wear. However, due to the decoupling of the left and right wheels, when the vehicle faces a single-wheel impact, the impact cannot be transmitted synchronously through the mechanical system. The coordination between the left and right wheels is easily disrupted, causing the vehicle to steer unexpectedly, making it extremely easy to lose control.

[0035] To address the aforementioned issues, this application provides a wheel angle control scheme. The scheme calculates the average wheel angle based on the steering wheel angle, and combines this with the ideal steering angle relationship between the inner and outer wheels and the Ackerman ratio formula to calculate the target steering angles for the left and right wheels. The actual steering angle of the wheels is then verified based on the calculated target angles. If the verification fails and the wheel cannot achieve the target steering angle, it indicates that the wheel has encountered a step and is stuck, or has experienced an unexpected steering reaction due to an external impact. In this way, the target steering angle of the other wheel is adjusted based on the actual steering angle of that wheel, ensuring coordinated steering between the left and right wheels. This allows the left and right wheels to respond quickly and coordinate effectively when the vehicle experiences an unexpected impact, thus effectively preventing vehicle instability caused by a single wheel impact.

[0036] The embodiments of this application will be described below: like Figure 2 As shown, Figure 2 This is a flowchart illustrating a wheel angle control method provided in an embodiment of this application. The method can be applied to the controller of a distributed steer-by-wire system. A steer-by-wire system is a technology that replaces the mechanical connection of a traditional steering system with electrical signal control. It eliminates the physical mechanical connection between the steering wheel and the steering wheels, using sensors to detect input signals from the steering wheel, and a servo motor to drive the steering mechanism to achieve steering. A distributed steer-by-wire system is a steering control scheme based on steer-by-wire technology. Its core feature is the elimination of the central steering mechanism, achieving independent or coordinated steering of all four wheels by independently controlling the steering motor of each wheel.

[0037] In this embodiment, the vehicle integrates a distributed steer-by-wire system, the structure of which is as follows: Figure 3 As shown, it includes a steering simulator 301 and a wheel-side steering unit 302. The steering simulator 301 and the wheel-side steering unit 302 are connected via a private CAN (Controller Area Network) bus. Both the steering simulator 301 and the wheel-side steering unit 302 are connected to the vehicle's CAN bus, and the left and right wheels are connected via the private CAN bus. In actual use, the steering simulator 301 is connected to the steering wheel, outputting the driver's steering angle command to the wheel-side steering unit 302, while simultaneously providing road feedback to the driver. Upon receiving the steering angle command from the steering simulator 301, the wheel-side steering unit 302 rotates the wheels to achieve steering. This distributed steer-by-wire system also includes a controller (not shown in the figure), i.e., a steer-by-wire controller. This controller is the "brain" of the distributed steer-by-wire system, responsible for processing sensor information and issuing commands to the wheel-side steering unit 302. This controller can be an Electronic Control Unit (ECU), containing components such as a microprocessor, memory, and input / output interfaces.

[0038] The method includes: Step 201: Calculate the average wheel angle based on the steering wheel angle, and then calculate the target wheel angles for the left and right wheels using the target wheel angle algorithm based on the average wheel angle; the average wheel angle is the average of the inner wheel angle and the outer wheel angle; the target wheel angle algorithm is based on the ideal angle relationship between the inner and outer wheels and the Ackerman ratio calculation formula. The target steering angle mentioned in this step is the desired steering angle of the wheels, calculated based on factors such as the driver's steering intention and the vehicle's driving status. In this embodiment, the steer-by-wire controller obtains the steering wheel angle from the vehicle's CAN bus, calculates the average wheel angle, and then combines it with the target wheel angle algorithm to calculate the target steering angles of the left and right wheels.

[0039] In practical applications, the ratio between the steering wheel angle and the average wheel angle is called the angular transmission ratio, which can be expressed as:

[0040] In equation (1), The angular transmission ratio; Steering wheel angle; This represents the average wheel steering angle. In the design of angular modules, the angular transmission ratio is typically designed as a variable ratio, as shown in the following diagram: Figure 4 As shown, by Figure 4 It can be seen that the angular transmission ratio changes with the vehicle speed to improve the vehicle's low-speed sensitivity and high-speed stability. In addition, the change in transmission ratio mainly affects the vehicle's yaw response and steering sensitivity. Specifically, the formula for calculating steering sensitivity is shown in equation (2):

[0041] In equation (2), Steering sensitivity; For vehicle speed; For vehicle quality; Wheelbase; This is the distance from the center of mass to the front axle; This is the distance from the center of mass to the rear axle; This refers to the lateral stiffness of the front wheel; The eccentric stiffness of the rear wheel; It represents the angular transmission ratio.

[0042] yaw rate The calculation formula is shown in equation (3):

[0043] Therefore, in some embodiments, the calculation of the average wheel angle based on the steering wheel angle mentioned in this step may include: calculating the angular transmission ratio based on the vehicle speed and yaw rate; and calculating the average wheel angle based on the current steering wheel angle and the angular transmission ratio. In other words, the steer-by-wire controller can collect the vehicle speed and yaw rate from the vehicle's CAN bus, substitute them into equation (3) to calculate the angular transmission ratio, and then substitute the calculated angular transmission ratio and the collected steering wheel angle into equation (1) to calculate the average wheel angle.

[0044] The target wheel steering angle algorithm mentioned in this step is based on the ideal steering angle relationship between the inner and outer wheels and the Ackerman ratio calculation formula. The ideal steering angle relationship between the inner and outer wheels can be expressed as:

[0045] In equation (4), The inner wheel rotation angle; For the outer wheel rotation angle; The center distance is the kingpin offset. Calculating the target wheel angle based on the ideal steering angle relationship between the inner and outer wheels can reduce tire wear during low-speed cornering. However, at high speeds, due to the larger slip angle of the wheels, the steering angles of the left and right wheels simply conforming to the ideal steering angle relationship between the inner and outer wheels are no longer sufficient for the overall vehicle requirements. Therefore, the steering angle of the outer wheel can be compensated to adapt to the vehicle's requirements. This is evaluated using the Ackerman ratio, defined as the percentage difference between the actual inner and outer wheel steering angles compared to the ideal difference. Since the lateral force changes of the outer wheel steering angle are more sensitive, and the angle is smaller, the outer wheel steering angle can be adjusted to adapt to the inner wheel steering angle. The Ackerman ratio can be expressed as:

[0046] In equation (5), For Ackerman's law, optionally, You can choose any value between 50% and 65%; This refers to the ideal steering angle of the outer wheel, also known as the ideal steering angle of the outer wheel. Obtaining the target steering angle based on the Ackermann relationship between the left and right wheels better meets the requirements of vehicle dynamics.

[0047] In some embodiments, calculating the target turning angles of the left and right wheels using the wheel target turning angle algorithm based on the average wheel turning angle mentioned in this step may include: establishing a first equation based on the average wheel turning angle; the unknowns of the first equation include the inner wheel turning angle and the outer wheel turning angle; establishing a second equation based on the ideal turning angle relationship between the inner and outer wheels; the unknowns of the second equation include the inner wheel turning angle and the ideal turning angle of the outer wheel; establishing a third equation based on the Ackermann ratio calculation formula; the unknowns of the third equation include the inner wheel turning angle, the outer wheel turning angle, and the ideal turning angle of the outer wheel; solving the system of equations consisting of the first equation, the second equation, and the third equation; and determining the target turning angles of the left and right wheels based on the solution results.

[0048] In other words, based on the average wheel rotation angle, the following first equation can be established:

[0049] Based on the ideal rotation angle relationship between the inner and outer wheels shown in equation (4), the second equation can be established as follows:

[0050] Based on the Ackerman rate calculation formula shown in equation (5), the following third-party process can be established:

[0051] Solving this system of three equations will yield the inner wheel rotation angle. and outer wheel angle The value of this value, combined with the vehicle's steering, allows us to determine the target turning angles for the left and right wheels. For example, when the vehicle turns left, the calculated inner wheel turning angle will be used. The target turning angle for the left wheel is determined, and the calculated turning angle of the outer wheel is then used. The target turning angle for the right wheel has been determined.

[0052] Step 202: Based on the target turning angle of either the left wheel or the right wheel, verify the actual turning angle of the wheel. The actual angle of rotation mentioned in this step refers to the actual rotation angle achieved by the wheel under control commands in a wired steering system, which can be obtained by an angle sensor installed on the steering knuckle. In this embodiment, the actual angle of rotation is verified based on the target angle of the wheel to determine whether the wheel angle meets expectations.

[0053] In some embodiments, this step may include: calculating the difference between the target turning angle and the actual executed turning angle of either the left or right wheel; if the absolute value of the difference is less than or equal to a target threshold, the verification is deemed successful; if the absolute value of the difference is greater than the target threshold, the verification is deemed unsuccessful. That is, a target threshold is preset. When the absolute value of the difference between the target turning angle and the actual executed turning angle of the wheel is less than or equal to the target threshold, the actual executed turning angle of the wheel is determined to meet expectations, and the verification is deemed successful. Conversely, when the absolute value of the difference between the target turning angle and the actual executed turning angle of the wheel is greater than the target threshold, the actual executed turning angle of the wheel is determined to not meet expectations, such as wheel overshoot, wheel misalignment, or unexpected steering, and the verification is deemed unsuccessful. The target threshold can be set to 0.5°. Of course, in other embodiments, the target threshold can also be set differently according to the needs of the specific scenario, and this application does not limit this.

[0054] Step 203: When the actual rotation angle verification of the wheel fails and the wheel cannot rotate toward the target angle, adjust the target angle of the other wheel based on the actual rotation angle of the wheel and the target rotation angle algorithm of the wheel.

[0055] In this embodiment, when the actual turning angle verification of the wheel fails, the steer-by-wire controller controls the wheel to continue turning towards the target angle. If the wheel cannot turn towards the target angle, it indicates that the wheel may encounter a step and get stuck, or it may encounter an unexpected impact from an external force. At this time, the steer-by-wire controller adjusts the target angle of the other wheel based on the actual turning angle of the wheel and the wheel target angle algorithm, so that the turning angles of the left and right wheels are coordinated, thereby avoiding vehicle instability caused by the impact of a single wheel and improving vehicle safety.

[0056] In some embodiments, the algorithm mentioned in this step, which adjusts the target angle of the other wheel based on the actual executed turning angle and the target turning angle of the wheel, may include: if the wheel is the inner wheel, substituting the actual executed turning angle of the wheel as the inner wheel turning angle into the system of equations to solve for the outer wheel turning angle, and adjusting the target turning angle of the other wheel to the outer wheel turning angle; if the wheel is the outer wheel, substituting the actual executed turning angle of the wheel as the outer wheel turning angle into the system of equations to solve for the inner wheel turning angle, and adjusting the target turning angle of the other wheel to the inner wheel turning angle. That is, when the wheel that fails the verification and cannot execute towards the target turning angle is the inner wheel, the actual executed turning angle of that wheel is taken as the inner wheel turning angle. Substitute the equations established earlier, and then, based on the recalculated outer wheel rotation angle... To adjust the target steering angle of the other wheel; similarly, when the wheel that fails the verification and cannot move toward the target steering angle is the outer wheel, the actual steering angle of that wheel is taken as the outer wheel steering angle. Substitute the equations established earlier, and then, based on the recalculated inner wheel rotation angle... This allows the target steering angle of the other wheel to be adjusted. In this way, when the vehicle is subjected to an unexpected impact, the left and right wheels can respond quickly and coordinate accordingly.

[0057] Furthermore, in some embodiments, the method may further include: when the actual steering angle verification of the wheel fails, but the wheel can perform steering towards the target angle, controlling the wheel to continue performing steering towards the target angle until the absolute value of the difference between the target angle and the actual steering angle is less than or equal to the target threshold. That is, when the actual steering angle verification of the wheel fails, the steer-by-wire controller controls the wheel to continue performing steering towards the target angle. If the wheel can perform steering towards the target angle, it indicates that the wheel has overshooted or is not performing correctly; at this point, the wheel is controlled to perform steering towards the expected angle until the verification passes. This ensures that the vehicle wheel steering angle meets expectations and satisfies vehicle dynamics requirements.

[0058] In a steer-by-wire system, the steering wheel and wheels interact only through electronic signals. If the steering wheel position remains unchanged after the wheel angle is adjusted, the driver will lose intuitive perception of the steering status. Thus, in emergency situations, the driver may misoperate the steering wheel due to a lack of feedback. Based on this, some embodiments may further include: when adjusting the target wheel angle, adjusting the steering wheel angle according to the current target angles of the left and right wheels and the vehicle speed, so that the steering wheel position matches the wheel angle. That is, when the vehicle experiences unexpected steering, the steer-by-wire controller adjusts the target wheel angle to coordinate the left and right wheel angles. At the same time, the steer-by-wire controller can recalculate the average wheel angle based on the adjusted target wheel angle, calculate the angular transmission ratio based on the vehicle speed at this moment, and then substitute it into equation (1) to obtain the steering wheel angle that matches the wheel angle, thereby adjusting the steering wheel position and providing accurate and effective feedback to the driver, thus ensuring driving safety.

[0059] Furthermore, in some embodiments, the method may also include: when the vehicle is braking or accelerating on a straight road, if the steering wheel angle is zero and the yaw rate is not zero, a PID control algorithm is used to calculate an angle compensation value with the yaw rate set to zero as the target, and the target steering angle is adjusted based on the angle compensation value. In other words, when the vehicle is braking or accelerating on a straight road, the vehicle speed, yaw rate, and steering wheel angle are collected from the vehicle's CAN bus. If the steering wheel angle is 0 and the yaw rate is not zero, it indicates that the driver's intention is to drive in a straight line, but the vehicle is yawing, which is inconsistent with the driver's intention. The vehicle is determined to be veering off course. At this time, a PID control algorithm can be used to set the yaw rate to 0 as the target, and an angle compensation value is given to one side of the vehicle's wheels. This angle compensation value is a steering angle directly superimposed on the target steering angle. For example, when a vehicle brakes or accelerates on a split road, the wheels on both sides may generate different braking or driving forces due to differences in adhesion, resulting in the vehicle being subjected to asymmetrical lateral forces, which in turn causes yaw motion. At this time, by superimposing the compensation value brought by the yaw response of the whole vehicle, the vehicle direction can be accurately and effectively corrected, thereby improving vehicle safety.

[0060] Furthermore, in some embodiments, the method may also include: when the vehicle is driving on a curve, if the vehicle's lateral acceleration exceeds a preset threshold, or the four wheel speeds do not operate as expected, a PID control algorithm is used to reduce the target steering angle of the outer wheels, with the lateral acceleration as the target acceleration value or the four wheel speeds as the target wheel speed value. In other words, when the vehicle is driving on a curve, the vehicle speed, lateral acceleration, wheel speed, and steering wheel angle are collected from the vehicle's CAN bus. If it is detected that the vehicle's lateral acceleration exceeds a preset threshold or the four wheel speeds do not operate as expected, indicating a tendency for the vehicle to become unstable, a PID control algorithm can be used to reduce the steering angle of the outer wheels, improve the vehicle's understeer, and thus enhance the vehicle's stability, with the lateral acceleration or four wheel speeds as the target.

[0061] In this embodiment, the average wheel angle is calculated based on the steering wheel angle. Combining the ideal steering angle relationship between the inner and outer wheels and the Ackerman ratio calculation formula, the target steering angles for the left and right wheels are calculated. The actual steering angles of the wheels are then verified based on the calculated target steering angles. If the verification fails and the wheel cannot achieve the target steering angle, it indicates an unexpected steering error. In this case, the target steering angle of the other wheel is adjusted based on the actual steering angle of that wheel, ensuring coordinated steering between the left and right wheels. This allows the left and right wheels to respond quickly and coordinate when the vehicle experiences an unexpected impact, effectively preventing vehicle instability caused by a single wheel impact.

[0062] To provide a more detailed explanation of the solution in this application, a specific embodiment is described below: This embodiment provides a distributed steer-by-wire wheel angle control scheme, the workflow of which is as follows: Figure 5 As shown, it includes: S501, obtain steering wheel angle, vehicle speed and yaw rate; S502, Calculate the angular transmission ratio; Specifically, substitute the vehicle speed and yaw rate collected from the vehicle's CAN bus into the previous formula (3), and then obtain the vehicle mass, wheelbase and other parameters from the vehicle design manual to calculate the angular transmission ratio. S503, Calculate the average wheel angle; Specifically, substitute the steering wheel angle collected from the vehicle's CAN bus and the calculated angular transmission ratio into the previous equation (1) to obtain the average wheel angle; S504. Based on the Ackerman relationship of the left and right wheels, the initial target turning angles of the left and right wheels are obtained, and then the angle compensation value brought by the yaw response of the whole vehicle is superimposed to obtain the final target turning angles of the left and right wheels. Specifically, the equation system composed of equations (6), (7) and (8) is solved to obtain the initial target turning angles of the left and right wheels. Based on the initial target turning angles, the angle compensation value brought by the yaw response of the whole vehicle is superimposed to obtain the final target turning angles of the left and right wheels. When the vehicle brakes or accelerates on the road surface, if the steering wheel angle is zero and the yaw rate is not zero, the vehicle uses the PID control algorithm to control the yaw rate of the vehicle to 0 as the target and calculates the angle compensation value. When the vehicle is driving on a high-speed curve, if the lateral acceleration of the vehicle exceeds the threshold or the speed of the four wheels does not operate as expected, the vehicle uses the PID control algorithm to control the lateral acceleration of the vehicle or the speed of the four wheels as the target and calculates the angle compensation value to reduce the turning angle of the outer wheel. S505. Based on the target turning angle of either the left or right wheel, verify the actual turning angle of that wheel. S506. Determine whether the verification passes. If yes, proceed to S507; otherwise, proceed to S508. Specifically, if the absolute value of the difference between the target turning angle of the wheel on this side and its actual turning angle is less than or equal to 0.5°, the verification passes. If the absolute value of the difference between the target turning angle of the wheel on this side and its actual turning angle is greater than 0.5°, the verification fails. S507. Confirm that the wheel on this side has been in position and end the process; S508. Determine whether the wheel on this side can continue to turn toward the target angle. If yes, execute S509; otherwise, execute S510. S509. Control the wheels on that side to continue turning toward the target angle until the verification is passed, then end the process. S510. Based on the actual turning angle of the wheel on this side, adjust the target turning angle of the wheel on the other side to make the turning angles of the left and right wheels coordinated. At the same time, according to the adjusted target turning angle of the wheel and the vehicle speed, adjust the steering wheel angle to match the position of the wheel, and then end the process.

[0063] This embodiment of the solution can ensure that the vehicle wheel turning angle meets the expected requirements and satisfies the vehicle dynamics requirements. At the same time, when the vehicle is subjected to an unexpected impact, the left and right wheels can respond quickly and coordinate to prevent the vehicle from becoming unstable due to the impact of a single wheel. It can also effectively provide feedback to the driver, allowing the driver to respond to the vehicle's feedback effectively and safely.

[0064] Corresponding to the embodiments of the aforementioned methods, this application also provides embodiments of a wheel steering angle control device and a terminal thereof: like Figure 6 As shown, Figure 6 This is a block diagram of a wheel steering angle control device provided in an embodiment of this application. The device is applied to the controller of a distributed steer-by-wire system; the device includes: The calculation module 61 is used to calculate the average wheel angle based on the steering wheel angle, and then calculate the target wheel angles of the left and right wheels based on the average wheel angle using a wheel target angle algorithm; the average wheel angle is the average of the inner wheel angle and the outer wheel angle; the wheel target angle algorithm is based on the ideal angle relationship between the inner and outer wheels and the Ackerman ratio calculation formula. Verification module 62 is used to verify the actual turning angle of the wheel based on the target turning angle of either the left wheel or the right wheel; The adjustment module 63 is used to adjust the target angle of the other wheel based on the actual angle of the wheel and the target angle algorithm when the actual angle of the wheel fails the verification and the wheel cannot turn toward the target angle.

[0065] The specific implementation process of the functions and roles of each module in the above device can be found in the implementation process of the corresponding steps in the above method, and will not be repeated here.

[0066] This application also provides an electronic device, please refer to [link to application]. Figure 7 , Figure 7 This is a structural block diagram of an electronic device provided in an embodiment of this application. The electronic device may include a processor 710, a communication interface 720, a memory 730, and at least one communication bus 740. The communication bus 740 is used to enable direct communication between these components. In this embodiment, the communication interface 720 of the electronic device is used for signaling or data communication with other node devices. The processor 710 may be an integrated circuit chip with signal processing capabilities.

[0067] The processor 710 described above can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), an off-the-shelf programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor, or the processor 710 can be any conventional processor.

[0068] The memory 730 may be, but is not limited to, random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), etc. The memory 730 stores computer-readable instructions, and when these computer-readable instructions are executed by the processor 710, the electronic device can perform the aforementioned operations. Figure 2 The various steps involved in the method implementation examples.

[0069] Alternatively, the electronic device may also include a storage controller and an input / output unit.

[0070] The memory 730, storage controller, processor 710, peripheral interface, and input / output unit are electrically connected directly or indirectly to achieve data transmission or interaction. For example, these components can be electrically connected to each other through one or more communication buses 740. The processor 710 is used to execute executable modules stored in the memory 730, such as software function modules or computer programs included in electronic devices.

[0071] The input / output unit is used to provide users with the ability to create tasks and to set optional start periods or preset execution times for those tasks, thereby enabling user-server interaction. The input / output unit may be, but is not limited to, a mouse and keyboard.

[0072] Understandable. Figure 7 The structure shown is for illustrative purposes only; the electronic device may also include components that are more advanced than those shown. Figure 7 The more or fewer components shown, or having the same Figure 7 The different configurations shown. Figure 7 The components shown can be implemented using hardware, software, or a combination thereof.

[0073] This application also provides a storage medium storing instructions. When the instructions are run on a computer, the computer program is executed by a processor to implement the method described in the method embodiment. To avoid repetition, the method will not be described again here.

[0074] This application also provides a computer program product that, when run on a computer, causes the computer to perform the method described in the method embodiment.

[0075] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can also be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0076] In addition, the functional modules in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0077] If the aforementioned functions are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0078] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application. It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0079] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0080] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A method for controlling wheel steering angle, characterized in that, A controller applied to a distributed steer-by-wire system; the method includes: The average wheel angle is calculated based on the steering wheel angle. Then, based on the average wheel angle, the target wheel angles for the left and right wheels are calculated using a wheel target angle algorithm. The average wheel angle is the average of the inner wheel angle and the outer wheel angle. The wheel target angle algorithm is based on the ideal angle relationship between the inner and outer wheels and the Ackerman ratio calculation formula. Based on the target turning angle of either the left wheel or the right wheel, the actual turning angle of the wheel is verified. When the actual rotation angle of the wheel fails the verification and the wheel cannot rotate toward the target angle, the target angle of the other wheel is adjusted based on the actual rotation angle of the wheel and the target rotation angle algorithm of the wheel.

2. The method according to claim 1, characterized in that, The calculation of the average wheel turning angle based on the steering wheel turning angle includes: Calculate the angular transmission ratio based on the vehicle speed and yaw rate; Calculate the average wheel angle based on the current steering wheel angle and the angular transmission ratio.

3. The method according to claim 2, characterized in that, The step of calculating the target turning angles of the left and right wheels based on the average turning angle of the wheels using a target turning angle algorithm includes: Based on the average wheel rotation angle, a first equation is established; the unknowns in the first equation include the inner wheel rotation angle and the outer wheel rotation angle. Based on the ideal rotation angle relationship between the inner and outer wheels, a second equation is established; the unknowns of the second equation include the rotation angle of the inner wheel and the ideal rotation angle of the outer wheel. A third process is established based on the Ackermann rate calculation formula; the unknowns of the third process include the inner wheel rotation angle, the outer wheel rotation angle, and the ideal outer wheel rotation angle. Solve the system of equations consisting of the first equation, the second equation, and the third equation, and determine the target turning angles of the left and right wheels based on the solution results.

4. The method according to claim 1, characterized in that, The step of verifying the actual turning angle of the wheels based on the target turning angle of either the left or right wheel includes: Calculate the difference between the target turning angle and the actual turning angle of either the left wheel or the right wheel; If the absolute value of the difference is less than or equal to the target threshold, the verification is deemed successful. If the absolute value of the difference is greater than the target threshold, the verification is determined to fail.

5. The method according to claim 4, characterized in that, Also includes: When the actual turning angle of the wheel fails the verification, and the wheel can turn toward the target turning angle, the wheel is controlled to continue turning toward the target turning angle until the absolute value of the difference between the target turning angle and the actual turning angle is less than or equal to the target threshold.

6. The method according to claim 3, characterized in that, The algorithm for adjusting the target angle of the other wheel based on the actual rotation angle of the wheel and the target rotation angle of the wheel includes: If the wheel is the inner wheel, the actual rotation angle of the wheel is used as the inner wheel rotation angle and substituted into the system of equations to solve for the outer wheel rotation angle, and the target rotation angle of the other wheel is adjusted to the outer wheel rotation angle; If the wheel is the outer wheel, the actual rotation angle of the wheel is substituted into the equation system as the outer wheel rotation angle to solve for the inner wheel rotation angle, and the target rotation angle of the other wheel is adjusted to the inner wheel rotation angle.

7. The method according to claim 1, characterized in that, Also includes: When adjusting the target turning angle of the wheels, the steering wheel angle is adjusted according to the current target turning angles of the left and right wheels and the overall vehicle speed, so that the position of the steering wheel matches the turning angle of the wheels.

8. The method according to claim 1, characterized in that, Also includes: When the vehicle brakes or accelerates on a straight road, if the steering wheel angle is zero and the yaw rate is not zero, the PID control algorithm calculates the angle compensation value with the goal of controlling the yaw rate to be zero, and adjusts the target steering angle based on the angle compensation value.

9. The method according to claim 1, characterized in that, Also includes: When the vehicle is driving on a curve, if the lateral acceleration of the vehicle exceeds a preset threshold, or the wheel speeds of the four wheels do not operate as expected, the PID control algorithm is used to reduce the target steering angle of the outer wheels by controlling the lateral acceleration as the target acceleration value or the wheel speeds of the four wheels as the target wheel speed value.

10. A wheel steering angle control device, characterized in that, A controller applied to a distributed steer-by-wire system; the device includes: The calculation module is used to calculate the average wheel angle based on the steering wheel angle, and then calculate the target wheel angles for the left and right wheels based on the average wheel angle using a wheel target angle algorithm; the average wheel angle is the average of the inner wheel angle and the outer wheel angle; the wheel target angle algorithm is based on the ideal angle relationship between the inner and outer wheels and the Ackerman ratio calculation formula. The verification module is used to verify the actual turning angle of the wheel based on the target turning angle of either the left wheel or the right wheel. The adjustment module is used to adjust the target angle of the other wheel based on the actual angle of the wheel and the target angle algorithm when the actual angle of the wheel fails the actual angle verification and the wheel cannot turn toward the target angle.

11. A computer-readable storage medium, characterized in that, It stores a computer program thereon, which, when executed by a processor, implements the method as described in any one of claims 1 to 9.

12. An electronic device, characterized in that, It includes a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the method as claimed in any one of claims 1 to 9.

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