Method and apparatus for controlling steering of rear wheels, and vehicle and storage medium

Abstract

Provided are a method and apparatus for controlling the steering of rear wheels, and a vehicle and a storage medium. The method for controlling the steering of rear wheels comprises: when a front-wheel steering-by-wire system fails, determining a steering control quantity of a steering wheel; on the basis of the steering control quantity, a target transmission ratio between the steering wheel and front wheels, and a yaw direction value, determining a target steering control quantity of rear wheels; and on the basis of the target steering control quantity, controlling the steering of the rear wheels. Since yaw is generated during the steering of front wheels, a yaw direction value is introduced when a target steering control quantity is determined, such that the same steering effect can be produced during the steering of the rear wheels and the steering of front wheels. Therefore, when a front-wheel steering-by-wire system fails, the method can not only aid, by means of the rear wheels, a vehicle in meeting steering requirements, but can also achieve a steering effect the same as that of the front wheels, thereby conforming to the steering habit of a vehicle user.

Description

Method, device, vehicle and storage medium for controlling rear wheel steering

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on October 27, 2023, with application number 202311411705.8 and application name “Method, device, vehicle and storage medium for controlling rear-wheel steering”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of vehicle technology, and in particular to a method, device, vehicle, and storage medium for controlling rear wheel steering in the field of vehicle technology. Background Art

[0003] Currently, vehicle steering is typically controlled by a steer-by-wire (SBW) system that controls the front wheels of the vehicle. However, the SBW system may fail.

[0004] If a vehicle equipped with a steer-by-wire system fails, the vehicle will be unable to steer effectively. To ensure driving safety, the rear wheels can be used to control the vehicle's trajectory and assist in steering. However, achieving the same steering effect as the front wheels through the rear wheels remains a pressing issue.

[0005] Summary of the Invention

[0006] The present application provides a method, device, vehicle and storage medium for controlling rear-wheel steering. This method can not only assist the vehicle in achieving steering requirements through the rear wheels when the front-wheel steer-by-wire system fails, thereby ensuring the safety of the vehicle user during vehicle driving, but also achieve the same steering effect as front-wheel steering, which is in line with the steering habits of the vehicle user.

[0007] In a first aspect, the present application provides a method for controlling rear wheel steering, the method comprising: determining a steering control amount of a steering wheel in the vehicle in the event that a front wheel steer-by-wire system of the vehicle fails; determining a target steering control amount of the rear wheels in the vehicle based on the steering control amount, a target transmission ratio between the steering wheel and the front wheels, and a yaw direction value, the yaw direction value being a numerical value indicating that the rotation direction of the rear wheels is opposite to the rotation direction of the front wheels when the steering wheel is rotated in the target direction; and controlling the rear wheel steering based on the target steering control amount.

[0008] In the above technical solution, if the front-wheel steer-by-wire system of a vehicle fails, the system cannot control the front wheels to steer the vehicle. Therefore, the rear wheels must intervene to steer the vehicle. In this solution, when the front-wheel steer-by-wire system fails, the steering control variable of the vehicle's steering wheel is determined. A target steering control variable for the rear wheels is determined based on this steering control variable, the target gear ratio between the steering wheel and the front wheels, and the yaw direction value. Because front-wheel steering generates yaw, which is caused by the rolling resistance of the wheels, this solution incorporates the yaw direction value when determining the target steering control variable for the rear wheels. This ensures that the yaw generated by rear-wheel steering is the same as that generated by front-wheel steering, producing the same steering effect. In determining the target steering control variable, the target angle of the rear wheel rotation is determined based on the steering control variable and the target gear ratio. Therefore, this solution not only ensures that the rear wheels assist in steering the vehicle in the event of a front-wheel steer-by-wire system failure, ensuring the safety of the vehicle's occupants during driving, but also achieves the same steering effect as front-wheel steering, conforming to the user's steering habits.

[0009] In combination with the first aspect, in some possible implementations, the front-wheel steer-by-wire system includes a steering wheel module and a steer-by-wire execution module, and the method for determining that the front-wheel steer-by-wire system of the vehicle has a fault includes: determining that the front-wheel steer-by-wire system has a fault when the number of times a first fault status signal sent by the steering wheel module is received within a first preset time period is greater than the first preset number; and / or determining that the front-wheel steer-by-wire system has a fault when the number of times a second fault status signal sent by the steer-by-wire execution module is received within a second preset time period is greater than the second preset number.

[0010] In the above technical solution, the front-wheel steer-by-wire system in the vehicle includes a steering wheel module and a steer-by-wire execution module. A malfunction in the front-wheel steer-by-wire system is often caused by a malfunction in the steering wheel module and / or the steer-by-wire execution module. Therefore, whether the front-wheel steer-by-wire system has malfunctioned can be determined by whether a first malfunction status signal from the steering wheel module has been received a number of times greater than a first preset number of times within a first preset time period; and / or whether a second malfunction status signal from the steer-by-wire execution module has been received a number of times greater than a second preset number of times within a second preset time period.

[0011] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, determining the steering control amount of the steering wheel in the vehicle includes: when the steering wheel module in the front-wheel wire-controlled steering system is not faulty, determining the steering control amount through the angle sensor in the steering wheel module; when the steering wheel module fails, obtaining the steering control amount from the target system through the controller local area network of the vehicle, and the target system is used to determine the steering control amount.

[0012] In the above technical solution, the front-wheel steer-by-wire system includes a steering wheel module and a steer-by-wire execution module. The steering wheel module includes a steering wheel and a steering angle sensor, and the steering wheel is connected to the steering angle sensor. When the steering wheel module does not malfunction, the various vehicle components in the steering wheel module can operate normally, so the steering control amount of the steering wheel can be determined by the steering angle sensor. This solution can determine the accurate steering control amount, and then obtain the accurate target steering control amount to more accurately control the rear wheel steering. In the event that the steering wheel module malfunctions, the steering control amount determined by other systems can be obtained through the vehicle CAN line (the vehicle's controller local area network). This solution can avoid the process of being unable to determine the steering control amount of the steering wheel when the steering wheel module malfunctions.

[0013] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, the target steering control amount of the rear wheels in the vehicle is determined based on the steering control amount, the target transmission ratio between the steering wheel and the front wheels, and the yaw direction value, including: determining the ratio between the steering control amount and the target transmission ratio as a first angle; and determining the product between the first angle and the yaw direction value as the target steering control amount.

[0014] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, controlling the rear wheel steering based on the target steering control amount includes: determining the target direction when the rear wheel rotates and the target angle value when the rear wheel rotates based on the target steering control amount; and controlling the rear wheel to rotate toward the target direction by the target angle value.

[0015] In the above technical solution, before determining wheel rotation, it is usually necessary to determine the wheel's rotation direction and rotation angle (value). Therefore, based on the target steering control variable, this solution determines the target direction and target angle value for rear wheel rotation; then controls the rear wheel to rotate toward the target direction and target angle value. In other words, in the event of a malfunction in the front wheel steer-by-wire system, the actual rotation of the rear wheel is used to achieve the same effect as the front wheel rotation, thereby meeting the vehicle user's steering needs and conforming to the vehicle user's steering habits.

[0016] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, in the event that a front-wheel steer-by-wire system of a vehicle fails, the steering control amount of the steering wheel in the vehicle is determined, including: in the event that the front-wheel steer-by-wire system fails, controlling the maximum turning angle value of the steering wheel that can be turned; in the event that the maximum turning angle value is limited, determining the steering control amount of the steering wheel in response to the rotation operation of the steering wheel.

[0017] In the above-mentioned technical solution, to improve vehicle stability during steering, the maximum steering angle of the rear wheels is often limited. Since the target steering control variable for the rear wheels in this solution is related to the steering control variable of the steering wheel, specifically the steering angle and direction, the maximum steering angle of the rear wheels can be indirectly limited by controlling the maximum steering angle of the steering wheel. Specifically, with the maximum steering angle limited, the steering control variable is determined in response to the steering wheel rotation operation. Thus, the rear wheel steering is controlled based on the target steering control variable, ensuring vehicle stability during steering and preventing loss of control.

[0018] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, the method also includes: detecting whether a rear-wheel steering system in the vehicle fails; and when the rear-wheel steering system does not fail, executing the step of determining the target steering control amount of the rear wheels in the vehicle based on the steering control amount, the target transmission ratio between the steering wheel and the front wheels, and the yaw direction value.

[0019] The above technical solution detects whether the rear-wheel steering system in the vehicle has a fault before the rear wheels are used to steer the vehicle. The target steering control variable for the rear wheels is determined only if the rear-wheel steering system is not faulty. This solution avoids the need to determine the target steering control variable even when the rear-wheel steering system has a fault, thereby avoiding the problem of wasted computing resources.

[0020] In a second aspect, the present application provides a device for controlling rear wheel steering, which includes: a determination module, used to: determine the steering control amount of the steering wheel in the vehicle when the front wheel wire-controlled steering system of the vehicle fails; determine the target steering control amount of the rear wheels in the vehicle based on the steering control amount, the target transmission ratio between the steering wheel and the front wheels, and the yaw direction value, the yaw direction value is a numerical value used to indicate that the rotation direction of the rear wheels is opposite to the rotation direction of the front wheels when the steering wheel is rotated in the target direction; a control module, used to control the rear wheel steering based on the target steering control amount.

[0021] In combination with the second aspect, in some possible implementations, the front-wheel steer-by-wire system includes a steering wheel module and a steer-by-wire execution module, and the determination module is specifically used to: determine that the front-wheel steer-by-wire system has a fault when the number of times the first fault status signal sent by the steering wheel module is received within a first preset time period is greater than the first preset number; and / or determine that the front-wheel steer-by-wire system has a fault when the number of times the second fault status signal sent by the steer-by-wire execution module is received within a second preset time period is greater than the second preset number.

[0022] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the determination module is further specifically used to: when the steering wheel module in the front-wheel wire-controlled steering system is not faulty, determine the steering control amount through the angle sensor in the steering wheel module; when the steering wheel module fails, obtain the steering control amount from the target system through the controller local area network of the vehicle, and the target system is used to determine the steering control amount.

[0023] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the determination module is further specifically used to: determine the ratio between the steering control amount and the target transmission ratio as a first angle; and determine the product between the first angle and the yaw direction value as the target steering control amount.

[0024] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the determination module is also used to determine the target direction of the rear wheel rotation and the target angle value of the rear wheel rotation based on the target steering control amount; the control module is specifically used to control the rear wheel to rotate toward the target direction and the target angle value.

[0025] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the control module is also used to control the maximum turning angle value of the steering wheel when a failure occurs in the front-wheel wire-controlled steering system; the determination module is specifically used to determine the steering control amount of the steering wheel in response to the rotation operation of the steering wheel when the maximum turning angle value is limited.

[0026] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the device also includes: a detection module for detecting whether a rear-wheel steering system in the vehicle fails; the determination module is also used to execute the step of determining the target steering control amount of the rear wheels in the vehicle based on the steering control amount, the target transmission ratio between the steering wheel and the front wheels, and the yaw direction value when the rear-wheel steering system does not fail.

[0027] In a third aspect, the present application provides a vehicle comprising a memory, a processor, and a computer program stored in the memory and running on the processor, wherein when the processor executes the computer program, the vehicle executes the method in the above-mentioned first aspect or any possible implementation of the first aspect.

[0028] In a fourth aspect, the present application provides a computer-readable storage medium, which stores instructions. When the instructions are executed on a computer or processor, the computer or processor executes the method in the above-mentioned first aspect or any possible implementation of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG1 is an architecture diagram of a front-wheel steer-by-wire system provided in an embodiment of the present application;

[0030] FIG2 is a schematic flow chart of a method for controlling rear wheel steering provided in an embodiment of the present application;

[0031] FIG3 is a block diagram of a method for controlling rear wheel steering provided in an embodiment of the present application;

[0032] FIG4 is a scene diagram of controlling rear wheel steering provided by an embodiment of the present application;

[0033] FIG5 is a schematic structural diagram of a device for controlling rear wheel steering provided in an embodiment of the present application;

[0034] FIG6 is a schematic structural diagram of a vehicle provided in an embodiment of the present application. DETAILED DESCRIPTION

[0035] The technical solutions in this application will be described clearly and in detail below in conjunction with the accompanying drawings. In the description of the embodiments of this application, "multiple" refers to two or more than two. The terms "first" and "second" are used for descriptive purposes only and should not be understood as implying or suggesting relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0036] Steer-by-wire systems eliminate the mechanical connection between the steering wheel and the steered wheels in traditional steering systems. Instead, they convert detected steering intentions into digital signals and transmit these signals to a steering controller, which then controls the steered wheels to complete the steering process. By eliminating mechanical connections like the steering column between the steering wheel and the steered wheels, steer-by-wire technology can significantly improve vehicle safety and prevent damage to the driver from the steering column in traffic accidents.

[0037] The steer-by-wire system consists of a steering wheel module and a steer-by-wire actuator module. The steering wheel module includes vehicle components such as the steering wheel, steering angle sensor, road sensor motor, and reduction gear mechanism. The steer-by-wire actuator module includes vehicle components such as the steering wheel, steering motor, and reduction gear mechanism. Furthermore, the steer-by-wire system also includes components such as the steering controller and power supply.

[0038] Among them, for the steering wheel module, the steering wheel is used to receive the driver's steering operation; the angle sensor is used to determine the steering wheel's rotation angle and rotation speed; the road sensing motor and deceleration mechanism can provide the driver with the vehicle's motion state, road surface state information and the steering wheel's return torque.

[0039] Among them, for the wire-controlled steering execution module, the steering motor and the speed reduction mechanism are used to overcome the steering resistance and drive the steering wheel to rotate a corresponding rotation angle.

[0040] The steering controller is configured to determine the rotation angle of the steering wheel based on the rotation angle of the steering wheel, and transmit a control signal for controlling the steering wheel to rotate by the rotation angle to the steering motor, so that the steering motor drives the steering wheel to rotate by the rotation angle. Furthermore, the power supply can be the entire vehicle power supply.

[0041] In some embodiments, the steered wheel is a front wheel of the vehicle. In the case where the steered wheel is a front wheel, the steer-by-wire system can be regarded as a front wheel steer-by-wire system.

[0042] Figure 1 is an architecture diagram of a front-wheel steer-by-wire system provided in an embodiment of the present application. As shown in Figure 1, the front-wheel steer-by-wire system of the vehicle shown in Figure 1 includes a steering wheel module and a steer-by-wire execution module. The steering wheels in the steer-by-wire execution module are the front wheels of the vehicle. In the event that the steering wheel module fails, the vehicle controller in the vehicle obtains the steering wheel rotation angle determined by the target system through the vehicle controller local area network (CAN) line, determines the rotation angle of the front wheels based on the rotation angle, and sends the control signal for controlling the front wheels to rotate the rotation angle to the steering motor in the steer-by-wire execution module through the vehicle CAN line. The steering motor drives the front wheels to rotate the rotation angle to achieve the steering requirement of the vehicle. It should be understood that the target system refers to any system in the vehicle that can determine the steering wheel rotation angle in the event that the steering wheel module fails.

[0043] It should be understood that the vehicle CAN line in the above solution is used for signal interaction between the wire-controlled steering system and the vehicle controller, and the private CAN line is used for interaction between signals within the wire-controlled steering system.

[0044] It should also be understood that due to long-term use of the front-wheel steer-by-wire system and external factors, the front-wheel steer-by-wire system may experience various faults. For example, the angle sensor in the steering wheel module may be unable to detect the steering wheel's rotation angle, and the steering motor in the steer-by-wire execution module may be unable to rotate. If any device in the front-wheel steer-by-wire system fails, the vehicle will not be able to achieve effective steering. Considering the safety of the vehicle's driving, the vehicle's driving trajectory can be controlled by the rear wheels to assist the vehicle in achieving steering requirements. However, how to achieve the steering effect of the front wheels through the rear wheels has become a problem that needs to be solved urgently.

[0045] To address the aforementioned issue of how to achieve the steering effect of the front wheels through the rear wheels, the present application provides a method for controlling rear-wheel steering. In the event that the front-wheel steer-by-wire system fails, the rear wheels can simulate front-wheel steering to achieve the vehicle's steering requirements and achieve the same steering effect as the front wheels. The following describes the method for controlling rear-wheel steering provided in an embodiment of the present application. For details, please refer to Figure 2, which is a schematic flow chart of a method for controlling rear-wheel steering provided in an embodiment of the present application.

[0046] It should be understood that the rear-wheel steering control method provided in the embodiments of the present application can be applied to the vehicle shown in Figure 1. Specifically, the rear-wheel steering control method can be applied to a target controller in the vehicle, which can be either a vehicle controller or a body domain controller. The body domain controller is used to control various vehicle components in the vehicle. When the target controller is a body domain controller, the body domain controller is used to control the rear wheels of the vehicle.

[0047] It should also be understood that the method for controlling rear-wheel steering in the present application is applicable to all vehicles that support steer-by-wire and are equipped with rear-wheel steering.

[0048] Exemplarily, as shown in FIG2 , the method 200 includes:

[0049] Step 201: When a front wheel steer-by-wire system of a vehicle fails, the vehicle controller determines a steering control amount of a steering wheel in the vehicle.

[0050] It should be understood that the "front-wheel steer-by-wire system" in step 201 above can be specifically understood as a steer-by-wire system in which the steered wheels are the front wheels of the vehicle. The front-wheel steer-by-wire system includes a steering wheel module, a steer-by-wire execution module, and a steering controller. In the solution of this application, the steering controller is specifically a vehicle controller. "Failure of the front-wheel steer-by-wire system" can be specifically understood as a failure of the steering wheel module and / or the steer-by-wire execution module.

[0051] It should also be understood that the "steering control amount of the steering wheel" in the above step 201 is equivalent to the "steering wheel rotation angle" in the above solution, specifically including the steering wheel rotation angle value and rotation direction.

[0052] In one possible implementation, the front-wheel steer-by-wire system includes a steering wheel module and a steer-by-wire execution module. The method for determining that the front-wheel steer-by-wire system of the vehicle has a fault in step 201 includes: when the number of times a first fault status signal sent by the steering wheel module is received within a first preset time period is greater than the first preset number, the vehicle controller determines that the front-wheel steer-by-wire system has a fault; and / or when the number of times a second fault status signal sent by the steer-by-wire execution module is received within a second preset time period is greater than the second preset number, the vehicle controller determines that the front-wheel steer-by-wire system has a fault.

[0053] It should be understood that in the above solution, the steering wheel module can send a first fault status signal to the vehicle controller through the vehicle CAN line, and the wire-controlled steering execution module can also send a second fault status signal to the vehicle controller through the vehicle CAN line.

[0054] In the above technical solution, the front-wheel steer-by-wire system in the vehicle includes a steering wheel module and a steer-by-wire execution module. A malfunction in the front-wheel steer-by-wire system is often caused by a malfunction in the steering wheel module and / or the steer-by-wire execution module. Therefore, whether the front-wheel steer-by-wire system has malfunctioned can be determined by specifically determining whether a first malfunction status signal from the steering wheel module has been received a number of times greater than a first preset number of times within a first preset time period; and / or whether a second malfunction status signal from the steer-by-wire execution module has been received a number of times greater than a second preset number of times within a second preset time period.

[0055] In some embodiments, the first preset number of times is the same as the second preset number of times, specifically 15 times.

[0056] In some embodiments, the first preset duration and the second preset duration are the same, specifically 10 ms.

[0057] In one possible implementation, the vehicle controller in step 201 determines the steering control amount of the steering wheel in the vehicle, including: when the steering wheel module in the front-wheel wire-steer system is not faulty, the vehicle controller determines the steering control amount through the angle sensor in the steering wheel module; when the steering wheel module fails, the vehicle controller obtains the steering control amount from the target system through the controller local area network of the vehicle, and the target system is used to determine the steering control amount.

[0058] It should be understood that when the steering wheel module does not malfunction, any device in the steering wheel module is able to work, so the vehicle controller can determine the steering control amount of the steering wheel through the angle sensor in the steering wheel module. In the event that the steering wheel module malfunctions, even if the angle sensor does not malfunction and the steering control amount of the steering wheel can be obtained, the steering control amount cannot be transmitted to the vehicle controller. Therefore, the present application obtains the steering control amount determined by other systems through the vehicle CAN line. This ensures that in the event that the steering wheel module in the front-wheel wire-controlled steering system malfunctions, the steering control amount can be obtained, thereby determining the target steering control amount of the rear wheels and assisting in completing the vehicle's steering requirements. Therefore, it is beneficial to ensure the safety of the vehicle.

[0059] It should also be understood that in the solution of the present application, if the steering wheel module in the front-wheel steer-by-wire system fails, the vehicle controller can intervene. The vehicle controller determines the steering controller of the steering wheel and, based on the steering control amount, the target gear ratio between the steering wheel and the front wheels, and the yaw direction value, determines the target steering control amount of the rear wheels of the vehicle; and controls the steering of the rear wheels based on the target steering control amount. If the steering wheel module is not faulty, the controller (i.e., the steering controller) in the front-wheel steer-by-wire system is used, which can be the determination module mentioned above in the device for controlling the rear-wheel steering.

[0060] In the above technical solution, the front-wheel steer-by-wire system includes a steering wheel module and a steer-by-wire execution module. The steering wheel module includes a steering wheel and a steering angle sensor, and the steering wheel is connected to the steering angle sensor. When the steering wheel module does not malfunction, the various vehicle components in the steering wheel module can operate normally, so the steering control amount of the steering wheel can be determined by the steering angle sensor. This solution can determine the accurate steering control amount, and then obtain the accurate target steering control amount to more accurately control the rear wheel steering. In the event that the steering wheel module malfunctions, the steering control amount determined by other systems can be obtained through the vehicle CAN line. This solution can avoid the process of being unable to determine the steering control amount of the steering wheel when the steering wheel module malfunctions.

[0061] In some embodiments, the target system includes a three-axis acceleration sensor in the vehicle, and the target system collects the vehicle's driving parameters in real time through the three-axis acceleration sensor to determine the rotation angle of the rear wheels; the target system determines the steering control amount of the steering wheel based on the rotation angle of the rear wheels.

[0062] It should be understood that the three-axis acceleration sensor can detect the acceleration, position, and speed of the vehicle in three-dimensional space.

[0063] In some embodiments, the vehicle controller determines the steering control amount of the steering wheel in the vehicle, including: in the event of a failure of the steering wheel module, the vehicle controller collects an initial image before the steering wheel is turned and a target image after the steering wheel is turned through a visual sensor in the vehicle, and the visual sensor is located above the steering wheel; the vehicle controller determines the steering control amount based on the initial position of the steering wheel in the initial image and the target position of the steering wheel in the target image.

[0064] In the above technical solution, if the steering wheel module fails, even if the angle sensor is not faulty and can obtain the steering control value of the steering wheel, it cannot transmit the steering control value to the vehicle controller. Therefore, this application adopts a visual method to determine the steering control value of the steering wheel. This ensures that in the event of a failure of the steering wheel module in the front-wheel steer-by-wire system, the steering control value can be obtained, thereby determining the target steering control value of the rear wheels and assisting in completing the vehicle's steering requirements. This is conducive to ensuring the safety of the vehicle.

[0065] In some embodiments, the visual sensor is any sensor that can capture a position image of the steering wheel in a visual manner.

[0066] In some embodiments, the visual sensor is a monocular camera or a multi-camera.

[0067] In some embodiments, the vehicle controller determines the steering control amount based on the initial position of the steering wheel in the initial image and the target position of the steering wheel in the target image, including: the vehicle controller determines a first position of the target reference point when the steering wheel is in the initial position and a second position of the target reference point when the steering wheel is in the target position; with the main center of the steering wheel as the origin, the vehicle controller determines the angle between the first line and the second line as the angle value of the steering wheel rotation in the steering control amount, and determines the direction of the steering wheel rotation in the steering control amount based on the position of the target reference point of the second position relative to the target reference point of the first position, the first line is the line between the target reference point of the first position and the origin, and the second line is the line between the target reference point of the second position and the origin.

[0068] It should be understood that, generally, different brands of vehicles have brand logos on their steering wheels. The brand logos include pictorial logos and / or letter logos. Therefore, the target reference point in the above solution can be a reference point on the pictorial logo or letter logo.

[0069] It should also be understood that steering wheels are typically circular and come in various styles, including two-spoke, three-spoke, and four-spoke. A two-spoke design refers to a steering wheel with two spokes; a three-spoke design refers to a steering wheel with three spokes; and a four-spoke design refers to a steering wheel with four spokes. Therefore, the steering control amount of the steering wheel can be determined by the changes in the positions of the spokes before and after the steering wheel is turned.

[0070] In some embodiments, the vehicle controller determines the direction of the steering wheel rotation in the steering control amount based on the position of the target reference point of the second position relative to the target reference point of the first position, including: when the target reference point of the second position is to the left of the target reference point of the first position, the vehicle controller determines that the direction is counterclockwise; when the target reference point of the second position is to the right of the target reference point of the first position, the vehicle controller determines that the direction is clockwise.

[0071] In one possible implementation, step 201 includes: in the event that the front-wheel steer-by-wire system fails, the vehicle controller controls the maximum turning angle value of the steering wheel; when the maximum turning angle value is limited, the vehicle controller determines the steering control amount of the steering wheel in response to the rotation operation of the steering wheel.

[0072] In the above-mentioned technical solution, to improve vehicle stability during steering, the maximum steering angle of the rear wheels is often limited. Since the target steering control variable for the rear wheels in this solution is related to the steering control variable of the steering wheel, specifically the steering angle and direction, limiting the maximum steering angle of the rear wheels can be achieved indirectly by controlling the maximum steering angle of the steering wheel. Specifically, with this maximum steering angle limited, the steering control variable is determined in response to the steering wheel's rotational operation. Thus, rear wheel steering is controlled based on the target steering control variable, ensuring that the vehicle remains stable during steering and is less likely to lose control.

[0073] In some embodiments, the maximum turning angle value is the product of the maximum turning angle value when the rear wheels turn and the target transmission ratio, and the target transmission ratio is the target transmission ratio between the steering wheel and the front wheels.

[0074] It should be understood that the maximum rear wheel rotation angle is 10 degrees. When the vehicle's front-wheel steer-by-wire system fails, the vehicle cannot achieve large steering angles through the rear wheels when traveling at low speeds. However, it can still meet driving needs in low-speed scenarios, for example, it can support vehicle parking. When the vehicle's front-wheel steer-by-wire system fails, the steering wheel rotation angle is generally within 180 degrees when the vehicle is traveling at high speed. The target transmission ratio is 18, and the corresponding rear wheel rotation angle is within 10 degrees, which can also meet the vehicle's high-speed driving needs.

[0075] In step 202, the vehicle controller determines a target steering control amount for the rear wheels of the vehicle based on the steering control amount, the target transmission ratio between the steering wheel and the front wheels, and the yaw direction value, wherein the yaw direction value is a value indicating that the rotation direction of the rear wheels is opposite to the rotation direction of the front wheels when the steering wheel is turned in the target direction.

[0076] It should be understood that the "target steering control amount of the rear wheel" in the above step 202 is equivalent to the "rotation angle of the rear wheel" in the above scheme, specifically including the target direction when the rear wheel rotates and the target angle value when the rear wheel rotates.

[0077] It should also be understood that, due to the turning angle characteristics of the vehicle, the "target transmission ratio" in step 202 gradually decreases as the steering wheel rotation angle increases. This is for vehicle safety considerations.

[0078] In one possible implementation, step 202 includes: the vehicle controller determines the ratio between the steering control amount and the target transmission ratio as a first angle; and the vehicle controller determines the product of the first angle and the yaw direction value as the target steering control amount.

[0079] It should be understood that the "first angle" in the above solution specifically refers to the rotation angle of the front wheels.

[0080] In some embodiments, the method for determining the yaw direction value includes: the vehicle controller determines the front wheel yaw angular velocity when the front wheel rotates based on the vehicle's driving speed, the distance between the front and rear wheels of the vehicle, and the front wheel turning angle, and determines the rear wheel yaw angular velocity when the rear wheel rotates based on the driving speed, the distance between the front and rear wheels, and the rear wheel turning angle; the vehicle controller determines the yaw direction value based on the front wheel yaw angular velocity and the rear wheel yaw angular velocity.

[0081] It should be understood that the "distance between the front and rear wheels of the vehicle" in the above solution specifically refers to the distance between the front and rear wheels on the same side. "Yaw rate" refers to the deflection of the wheels in the vehicle about the vertical axis, and can be simply understood as the speed at which the wheels swing in the lateral direction.

[0082] It should also be understood that the “front wheel turning angle” and “rear wheel turning angle” in the above solution are used to generally refer to the rotation angle of the wheels and have no specific meaning.

[0083] In some embodiments, the vehicle controller determines the front wheel yaw rate when the front wheel rotates based on the vehicle's driving speed, the distance between the front and rear wheels of the vehicle, and the front wheel turning angle, including: the vehicle controller determines the front wheel yaw rate based on the following formula (1);

[0084] Among them, ω1 is the front wheel yaw rate, v is the driving speed, L is the distance between the front and rear wheels, δ f is the front wheel turning angle, and K is a constant.

[0085] In some embodiments, the vehicle controller determines the rear wheel yaw rate when the rear wheel rotates based on the driving speed, the distance between the front and rear wheels, and the rear wheel turning angle, including: the vehicle controller determines the rear wheel yaw rate based on the following formula (2);

[0086] Among them, ω2 is the rear wheel yaw rate, v is the driving speed, L is the distance between the front and rear wheels, δ r is the front wheel turning angle, and K is a constant.

[0087] In some embodiments, the vehicle controller determines the yaw direction value based on the front wheel yaw angular velocity and the rear wheel yaw angular velocity, including: the vehicle controller determines the ratio between a first numerical value corresponding to the front wheel yaw angular velocity and a second numerical value corresponding to the rear wheel yaw angular velocity as the yaw direction value, the first numerical value is a numerical value used to indicate the positive or negative yaw angular velocity of the front wheel, and the second numerical value is a numerical value used to indicate the positive or negative yaw angular velocity of the rear wheel.

[0088] It should be understood that during actual driving, the direction of the front wheel yaw velocity differs from that of the rear wheel yaw velocity. Therefore, when simulating front wheel steering with the rear wheels, the impact of yaw velocity must be considered to achieve the same steering effect as the front wheels. To address this, the present application incorporates a yaw direction value when determining the target steering control amount for the rear wheels. This ensures that when the rear wheels steer with this target steering control amount, they achieve the same steering effect as the front wheels, conforming to the vehicle user's steering habits.

[0089] In one possible implementation, the method 200 further includes: the vehicle controller detecting whether a rear-wheel steering system in the vehicle fails; if the rear-wheel steering system does not fail, the vehicle controller executing a step of determining a target steering control amount for the rear wheels in the vehicle based on the steering control amount, the target transmission ratio between the steering wheel and the front wheels, and the yaw direction value.

[0090] The above technical solution detects whether the rear-wheel steering system in the vehicle has a fault before the rear wheels are used to steer the vehicle. The target steering control variable for the rear wheels is determined only if the rear-wheel steering system is not faulty. This solution avoids the need to determine the target steering control variable even when the rear-wheel steering system has a fault, thereby avoiding the problem of wasted computing resources.

[0091] Step 203: The vehicle controller controls the rear wheel steering based on the target steering control amount.

[0092] In one possible implementation, step 203 includes: the vehicle controller determines the target direction and target angle value of the rear wheel rotation based on the target steering control amount; and the vehicle controller controls the rear wheel to rotate toward the target direction by the target angle value.

[0093] In the above technical solution, before determining wheel rotation, it is usually necessary to determine the wheel's rotation direction and rotation angle (value). Therefore, based on the target steering control variable, this solution determines the target direction and target angle value for rear wheel rotation; then controls the rear wheel to rotate toward the target direction and target angle value. In other words, in the event of a malfunction in the front wheel steer-by-wire system, rotating the rear wheel will have the same effect as rotating the front wheel, thereby meeting the vehicle user's steering needs and conforming to the vehicle user's steering habits.

[0094] In some embodiments, the vehicle controller determines the target direction and target angle value of the rear wheel when the rear wheel rotates based on the target steering control amount, including: when the target steering control amount is a positive value, the vehicle controller determines the clockwise direction as the target direction and determines the absolute value of the target steering control amount as the target angle value; when the target steering control amount is a negative value, the vehicle controller determines the counterclockwise direction as the target direction and determines the absolute value of the target steering control amount as the target angle value.

[0095] In some embodiments, after step 203, the method 200 further includes: the vehicle controller controls the display screen of the vehicle to display a reminder message or controls the voice output device of the vehicle to broadcast the reminder message, and the reminder message is used to remind that the steering of the vehicle is being controlled by the rear wheels.

[0096] In the above technical solution, after the vehicle controller determines that the rear wheels need to be steered based on the target steering control amount, the vehicle controller controls the vehicle to output the reminder information. This can remind the user on the vehicle that the vehicle is steering via the rear wheels and can prompt the user to adjust their sitting posture to avoid collisions.

[0097] Next, please refer to Figure 3, which is a block diagram of a method for controlling rear-wheel steering provided in an embodiment of the present application. Exemplarily, as shown in Figure 3, if a first fault status signal is not received from a steering wheel module in a front-wheel steer-by-wire system of a vehicle within a first preset duration, but a second fault status signal is received from a steer-by-wire execution module in the front-wheel steer-by-wire system a number of times greater than a second preset duration, the vehicle controller determines that a fault has occurred in the steer-by-wire execution module and the front-wheel steer-by-wire system, making it impossible to steer the vehicle through the front wheels. The vehicle controller obtains the steering control amount of the steering wheel through the steering angle sensor in the steering wheel module, and obtains the driving speed of the vehicle through the wheel speed signal of the vehicle; the vehicle controller determines the front wheel yaw rate when the front wheels of the vehicle rotate based on the driving speed, the distance between the front and rear wheels of the vehicle and the front wheel angle, and determines the rear wheel yaw rate when the rear wheels of the vehicle rotate based on the driving speed, the distance between the front and rear wheels of the vehicle and the rear wheel angle; the vehicle controller determines the yaw direction value based on the front wheel yaw rate and the rear wheel yaw rate, and the yaw direction value is a numerical value used to indicate that the rotation direction of the rear wheels is opposite to the rotation direction of the front wheels when the steering wheel is rotated in the target direction; the vehicle controller determines the target steering control amount of the rear wheels based on the steering control amount, the target transmission ratio between the steering wheel and the front wheels, and the yaw direction value; the vehicle controller determines the target direction when the rear wheels rotate and the target angle value when the rear wheels rotate based on the target steering control amount. The vehicle controller sends the target direction and the target angle value of the rear wheel rotation to the steering motor corresponding to the rear wheel, so that the steering motor drives the rear wheel to rotate toward the target direction by the target angle value.

[0098] In another exemplary embodiment, as shown in FIG3 , when the vehicle controller receives a first fault status signal from a steering wheel module in the front-wheel steer-by-wire system of the vehicle greater than a first preset number of times within a first preset time period, the vehicle controller determines that the steering wheel module has failed, the front-wheel steer-by-wire system has failed, and the vehicle cannot be steered by the front wheels. The vehicle controller obtains the steering control amount of the steering wheel determined by other systems through the vehicle CAN line, and obtains the driving speed of the vehicle through the wheel speed signal of the vehicle; the vehicle controller determines the front wheel yaw rate when the front wheels of the vehicle rotate based on the driving speed, the distance between the front and rear wheels of the vehicle and the front wheel turning angle, and determines the rear wheel yaw rate when the rear wheels of the vehicle rotate based on the driving speed, the distance between the front and rear wheels of the vehicle and the rear wheel turning angle; the vehicle controller determines the yaw direction value based on the front wheel yaw rate and the rear wheel yaw rate, and the yaw direction value is used to indicate that the rotation direction of the rear wheels is opposite to the rotation direction of the front wheels when the steering wheel is rotated in the target direction; the vehicle controller determines the target steering control amount of the rear wheels based on the steering control amount, the target transmission ratio between the steering wheel and the front wheels, and the yaw direction value; the vehicle controller determines the target direction when the rear wheels rotate and the target angle value when the rear wheels rotate based on the target steering control amount. The vehicle controller sends the target direction and the target angle value of the rear wheel rotation to the steering motor corresponding to the rear wheel, so that the steering motor drives the rear wheel to rotate toward the target direction by the target angle value.

[0099] Next, please refer to Figure 4, which is a scene diagram of controlling rear wheel steering provided in an embodiment of the present application. Exemplarily, as shown in Figure 4, in the case where the front wheel wire-controlled steering system of the vehicle fails, the vehicle controller receives a steering demand for the vehicle and determines the steering control amount of the steering wheel in the vehicle. In the case where the steering control amount indicates that the steering wheel is turned in the clockwise direction, the vehicle controller determines the target rotation angle value of the rear wheel in the vehicle based on the steering control amount and the target transmission ratio between the steering wheel and the front wheel. The vehicle controller controls the rear wheel to rotate in the counterclockwise direction to the target rotation angle value. Corresponding to the aforementioned method 200, in the embodiment shown in Figure 4, the target steering control amount in the method 200 includes the target direction when the rear wheel rotates being counterclockwise, and the target angle value when the rear wheel rotates being the target rotation angle value.

[0100] FIG5 is a schematic structural diagram of a device for controlling rear wheel steering provided in an embodiment of the present application.

[0101] Exemplarily, as shown in FIG5 , the apparatus 500 includes:

[0102] The determination module 501 is configured to:

[0103] determining a steering control amount of a steering wheel in the vehicle in the event of a malfunction in a front wheel steer-by-wire system of the vehicle; determining a target steering control amount of rear wheels in the vehicle based on the steering control amount, a target gear ratio between the steering wheel and the front wheels, and a yaw direction value, the yaw direction value being a value indicating that a rotation direction of the rear wheels is opposite to a rotation direction of the front wheels when the steering wheel is turned in the target direction;

[0104] The control module 502 is configured to control the rear wheel steering based on the target steering control amount.

[0105] Optionally, the front-wheel steer-by-wire system includes a steering wheel module and a steer-by-wire execution module, and the determination module 501 is specifically used to: determine that the front-wheel steer-by-wire system has a fault when the number of times a first fault status signal sent by the steering wheel module is received within a first preset time period is greater than a first preset number; and / or determine that the front-wheel steer-by-wire system has a fault when the number of times a second fault status signal sent by the steer-by-wire execution module is received within a second preset time period is greater than a second preset number.

[0106] Optionally, the determination module 501 is further specifically used to: when the steering wheel module in the front-wheel wire-controlled steering system is not faulty, determine the steering control amount through the angle sensor in the steering wheel module; when the steering wheel module fails, obtain the steering control amount from the target system through the controller local area network of the vehicle, and the target system is used to determine the steering control amount.

[0107] Optionally, the determination module 501 is further configured to: determine a ratio between the steering control amount and the target transmission ratio as a first angle; and determine a product of the first angle and the yaw direction value as the target steering control amount.

[0108] Optionally, the determination module 501 is further used to determine the target direction and target angle value of the rear wheel rotation based on the target steering control amount; the control module 502 is specifically used to control the rear wheel to rotate toward the target direction and the target angle value.

[0109] Optionally, the control module 502 is also used to control the maximum turning angle value of the steering wheel when the front-wheel wire-controlled steering system fails; the determination module 501 is specifically further used to determine the steering control amount of the steering wheel in response to the rotation operation of the steering wheel when the maximum turning angle value is limited.

[0110] Optionally, the device 500 also includes: a detection module for detecting whether a rear-wheel steering system in the vehicle fails; the determination module 501 is also used to execute the step of determining the target steering control amount of the rear wheels in the vehicle based on the steering control amount, the target transmission ratio between the steering wheel and the front wheels, and the yaw direction value when the rear-wheel steering system does not fail.

[0111] FIG6 is a schematic structural diagram of a vehicle provided in an embodiment of the present application.

[0112] Exemplarily, as shown in FIG6 , the vehicle 600 includes: a memory 601, a processor 602, and a computer program 603 stored in the memory 601 and running on the processor 602, wherein when the processor 602 executes the computer program 603, the vehicle can execute any one of the methods for controlling rear wheel steering described above.

[0113] This embodiment can divide the vehicle into functional modules based on the above-described method example. For example, each functional module can be mapped to a specific function, or two or more functions can be integrated into a single processing module. The integrated module can be implemented in hardware. It should be noted that the module division in this embodiment is illustrative and represents only one logical functional division. In actual implementation, other division methods may be used.

[0114] In the case of dividing each functional module into corresponding functional modules, the vehicle may include: a determination module, a control module, a detection module, etc. It should be noted that all relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding functional module and will not be repeated here.

[0115] The vehicle provided in this embodiment is used to execute the above-mentioned method of controlling rear wheel steering, and thus can achieve the same effect as the above-mentioned implementation method.

[0116] In the case of an integrated unit, the vehicle may include a processing module and a storage module. The processing module may be used to control and manage the vehicle's movements, while the storage module may be used for the vehicle to execute program codes and data.

[0117] The processing module may be a processor or controller that implements or executes various exemplary logic blocks, modules, and circuits disclosed herein. The processor may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a digital signal processing (DSP) and a microprocessor, and the storage module may be a memory.

[0118] This embodiment provides a computer-readable storage medium having instructions stored therein. When the instructions are executed on a computer or a processor, the computer or processor executes any one of the methods for controlling rear wheel steering described above.

[0119] This embodiment also provides a computer program product containing instructions. When the computer program product is run on a computer or a processor, it enables the computer or the processor to execute the above-mentioned related steps to implement any of the methods for controlling rear wheel steering described above.

[0120] Among them, the vehicle, computer-readable storage medium, computer program product or chip containing instructions provided in this embodiment are all used to execute the corresponding methods provided above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding methods provided above, and will not be repeated here.

[0121] Through the description of the above implementation methods, technical personnel in the relevant field can understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0122] In the embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of modules or units is only a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0123] The above content is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A method for controlling rear wheel steering, characterized in that: The method comprises: determining a steering control amount of a steering wheel in the vehicle in the event of a failure of a front wheel steer-by-wire system of the vehicle; determining a target steering control amount for rear wheels in the vehicle based on the steering control amount, a target transmission ratio between the steering wheel and the front wheels, and a yaw direction value, wherein the yaw direction value is a value indicating that the rotation direction of the rear wheels is opposite to the rotation direction of the front wheels when the steering wheel is turned in the target direction; The rear wheel steering is controlled based on the target steering control amount.

2. The method according to claim 1, characterized in that: The front wheel steer-by-wire system comprises a steering wheel module and a steer-by-wire execution module, and the method for determining that the front wheel steer-by-wire system of the vehicle has a fault comprises: When the number of times the first fault status signal sent by the steering wheel module is received within the first preset time period is greater than the first preset number of times, determining that the front wheel steer-by-wire system has a fault; and / or, When the number of times the second fault status signal sent by the steer-by-wire execution module is received within the second preset time period is greater than the second preset number, it is determined that the front-wheel steer-by-wire system has a fault.

3. The method according to claim 1, characterized in that The determining of the steering control amount of the steering wheel in the vehicle comprises: In the case where the steering wheel module in the front wheel steer-by-wire system does not fail, determining the steering control amount by means of a steering angle sensor in the steering wheel module; In the event of a failure of the steering wheel module, the steering control amount is acquired from a target system via a controller area network of the vehicle, and the target system is used to determine the steering control amount.

4. The method according to claim 1, characterized in that: The step of determining a target steering control amount for rear wheels of the vehicle based on the steering control amount, a target transmission ratio between the steering wheel and the front wheels, and a yaw direction value comprises: determining a ratio between the steering control amount and the target transmission ratio as a first angle; The product of the first angle and the yaw direction value is determined as the target steering control amount.

5. The method according to claim 4, characterized in that The controlling the rear wheel steering based on the target steering control amount comprises: Determining a target direction when the rear wheels rotate and a target angle value when the rear wheels rotate based on the target steering control amount; The rear wheel is controlled to rotate toward the target direction by the target angle value.

6. The method according to claim 1, characterized in that The method of determining a steering control amount of a steering wheel in the vehicle when a front wheel steer-by-wire system of the vehicle fails comprises: In the event of a failure of the front wheel steer-by-wire system, controlling the maximum rotatable angle of the steering wheel; In the case where the maximum turning angle value is limited, a steering control amount of the steering wheel is determined in response to a turning operation of the steering wheel.

7. The method according to any one of claims 1 to 6, characterized in that: The method further comprises: detecting whether a rear wheel steering system in the vehicle fails; In the case where the rear-wheel steering system does not fail, the step of determining the target steering control amount of the rear wheels in the vehicle based on the steering control amount, the target gear ratio between the steering wheel and the front wheels, and the yaw direction value is performed.

8. A device for controlling rear wheel steering, characterized in that: The device comprises: Identify modules for: determining a steering control amount of a steering wheel in the vehicle in the event of a failure of a front wheel steer-by-wire system of the vehicle; determining a target steering control amount for rear wheels in the vehicle based on the steering control amount, a target transmission ratio between the steering wheel and the front wheels, and a yaw direction value, wherein the yaw direction value is a value indicating that the rotation direction of the rear wheels is opposite to the rotation direction of the front wheels when the steering wheel is turned in the target direction; A control module is used to control the rear wheel steering based on the target steering control amount.

9. A vehicle, characterized in that: The invention comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the vehicle executes the method for controlling rear wheel steering as claimed in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores instructions, and when the instructions are executed on a computer or a processor, the computer or the processor executes the method for controlling rear wheel steering according to any one of claims 1 to 7.

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