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

Abstract

The invention provides a method and device for controlling steering of rear wheels, a vehicle and a storage medium. When a front wheel steer-by-wire system of the vehicle breaks down, the front wheel steer-by-wire system cannot control front wheel steering. Therefore, rear wheel intervention is needed to achieve vehicle steering. According to the scheme, when the front wheel steer-by-wire system fails, the steering control quantity of a steering wheel is determined; a target steering control amount of the rear wheels is determined based on the steering control amount, a target gear ratio between the steering wheel and the front wheels, and the yaw direction value. Due to the fact that yawing can be generated in front wheel steering, the yawing direction value is introduced when the target steering control quantity is determined in the scheme. Therefore, the steering effect of the rear wheel is the same as that of the front wheel. A target angle value for rear wheel rotation is also determined based on the steering control amount and the target gear ratio. Therefore, according to the scheme, when the front wheel steer-by-wire system fails, the vehicle can be assisted by the rear wheels to meet the steering requirement, the steering effect the same as that of the front wheels is achieved, and the steering habit of a vehicle user is met.

Description

Technical Field

[0001] The present application relates to the field of vehicles, and more specifically, to a method, a device, a vehicle and a storage medium for controlling rear wheel steering in the field of vehicles. Background Art

[0002] At present, the steering control of a vehicle is usually controlled by a steer-by-wire (SBW) system to control the steering of the front wheels of the vehicle. However, the SBW system may fail.

[0003] For vehicles equipped with a steer-by-wire system, if the steer-by-wire system fails, the vehicle will not be able to achieve effective steering. Considering the driving safety of the vehicle, 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 an urgent problem to be solved. Summary of the invention

[0004] The present application provides a method, device, vehicle and storage medium for controlling rear-wheel steering. The method can not only achieve steering requirements through the rear wheels to assist the vehicle in achieving steering requirements when the front-wheel wire-controlled steering system fails, thereby ensuring the safety of vehicle users during vehicle driving, but also achieve the same steering effect as front-wheel steering, which is in line with the steering habits of vehicle users.

[0005] In a first aspect, a method for controlling rear wheel steering is provided, the method comprising: in case a front wheel steer-by-wire system of the vehicle fails, determining a steering control amount of a steering wheel in the vehicle; determining a target steering control amount for 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 for indicating that the rotation direction of the rear wheels is opposite to that of the front wheels when the steering wheel is turned in the target direction; and controlling the rear wheel steering based on the target steering control amount.

[0006] In the above technical solution, when the front wheel steer-by-wire system of the vehicle fails, the front wheel steer-by-wire system cannot control the front wheel to realize vehicle steering. Therefore, the rear wheel needs to intervene to realize vehicle steering. When the front wheel steer-by-wire system fails, the solution determines the steering control amount of the steering wheel in the vehicle; based on the steering control amount, the target transmission ratio between the steering wheel and the front wheel, and the yaw direction value, the target steering control amount of the rear wheel is determined. Since the front wheel steering will produce yaw, which is caused by the rolling resistance of the wheel, the solution introduces the yaw direction value in the process of determining the target steering control amount of the rear wheel. This can make the yaw generated when the rear wheel is turned the same as the yaw generated when the front wheel is turned, and produce the same steering effect. In the process of determining the target steering control amount, the target angle value of the rear wheel rotation can be determined based on the steering control amount and the target transmission ratio. Therefore, the solution can not only realize the steering demand through the rear wheel assist vehicle in the case of the failure of the front wheel steer-by-wire system, and ensure the safety of the users on the vehicle during the driving of the vehicle, but also achieve the same steering effect as the front wheel steering, which conforms to the steering habits of the vehicle users.

[0007] 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 a method for determining that a 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 a first preset number of times; 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 a second preset number of times.

[0008] 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. The malfunction of the front wheel steer-by-wire system is often caused by the malfunction of the steering wheel module and / or the steer-by-wire execution module. Therefore, it can be determined whether the front wheel steer-by-wire system has a malfunction by whether the number of times the first malfunction status signal sent by the steering wheel module is received within a first preset time period is greater than the first preset number of times; and / or whether the number of times the second malfunction 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 of times.

[0009] 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, acquiring 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.

[0010] In the above technical solution, the front wheel wire-controlled steering system includes a steering wheel module and a wire-controlled steering execution module, and 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 fail, the various vehicle components in the steering wheel module can work 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 fails, the steering control amount determined by other systems can be obtained through the vehicle CAN line (the vehicle's controller 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 fails.

[0011] 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; determining the product between the first angle and the yaw direction value as the target steering control amount.

[0012] 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; controlling the rear wheel to rotate toward the target direction by the target angle value.

[0013] In the above technical solution, usually before determining the rotation of the wheel, it is necessary to determine the rotation direction and rotation angle (value) of the wheel. Therefore, the solution determines 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 then controls the rear wheel to rotate to the target direction by the target angle value. In other words, in the event of a failure in the front wheel steer-by-wire system, the actual rotation of the rear wheel is equivalent to the effect of the front wheel rotation, so as to meet the vehicle user's steering needs for the vehicle and meet the vehicle user's steering habits.

[0014] 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, a steering control amount of a 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 a turning operation of the steering wheel.

[0015] In the above technical solution, in order to improve the stability of the vehicle body during steering, the maximum turning angle value of the rear wheels during steering is often limited. Since the target steering control amount of the rear wheels in this solution is related to the steering control amount of the steering wheel, and the steering control amount is specifically the turning angle value and the turning direction, the maximum turning angle value of the rear wheels during steering can be indirectly limited by controlling the maximum turning angle value of the steering wheel. That is, under the condition of the maximum turning angle value limitation, the steering control amount of the steering wheel is determined in response to the turning operation of the steering wheel. Therefore, the rear wheel steering is controlled based on the target steering control amount, so that the vehicle body is kept stable during the steering process and is not prone to loss of control.

[0016] 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; when the rear-wheel steering system does not fail, executing the 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.

[0017] In the above technical solution, it is equivalent to detecting whether the rear wheel steering system in the vehicle fails before the vehicle is turned by the rear wheels. The target steering control amount of the rear wheels is determined only when the rear wheel steering system does not fail. This solution can avoid the process of determining the target steering control amount when the rear wheel steering system fails, which can avoid the problem of wasting computing resources.

[0018] In a second aspect, a device for controlling rear wheel steering is provided, the device comprising: a determination module, used to: determine the steering control amount of the steering wheel in the vehicle when a 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 being a numerical value indicating that the rotation direction of the rear wheels is opposite to that of the front wheels when the steering wheel is turned in the target direction; and a control module, used to control the rear wheel steering based on the target steering control amount.

[0019] 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 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 of times; 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 of times.

[0020] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the determination module is specifically further 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 steering 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.

[0021] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the determination module is specifically used to: determine the ratio between the steering control amount and the target transmission ratio as a first angle; determine the product between the first angle and the yaw direction value as the target steering control amount.

[0022] 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 when it turns and the target angle value of the rear wheel when it turns 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.

[0023] 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 the front-wheel wire-controlled steering system fails; 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.

[0024] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the device also includes: a detection module, used to detect 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.

[0025] In a third aspect, a vehicle is provided, 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.

[0026] In a fourth aspect, a computer-readable storage medium is provided, which stores instructions. When the instructions are executed on a computer or a processor, the computer or the processor executes the method in the first aspect or any possible implementation of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is an architecture diagram of a front wheel steer-by-wire system provided in an embodiment of the present application;

[0028] Figure 2 is a schematic flow chart of a method for controlling rear wheel steering provided in an embodiment of the present application;

[0029] Figure 3 is a block diagram of a method for controlling rear wheel steering provided in an embodiment of the present application;

[0030] Figure 4 is a scene diagram for controlling rear wheel steering provided in an embodiment of the present application;

[0031] Figure 5 is a schematic structural diagram of a device for controlling rear wheel steering provided in an embodiment of the present application;

[0032] Figure 6 It is a structural schematic diagram of a vehicle provided in an embodiment of the present application. DETAILED DESCRIPTION

[0033] The technical solutions in the present application will be described clearly and in detail below in conjunction with the accompanying drawings. In the description of the embodiments of the present application, "multiple" means 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. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0034] The steer-by-wire system eliminates the mechanical connection between the steering wheel and the steering wheel in the traditional steering system. It converts the detected steering intention into a digital signal and transmits the digital signal to the steering controller, which then controls the steering wheel to complete the steering process. Since the steer-by-wire system eliminates the mechanical connection between the steering wheel and the steering wheel, such as the steering column, the steer-by-wire technology can greatly improve the vehicle's safe driving performance and prevent the steering column from harming the driver in traffic accidents.

[0035] The steer-by-wire system includes a steering wheel module and a steer-by-wire execution module. The steering wheel module includes vehicle components such as a steering wheel, a steering angle sensor, a road sensing motor, and a deceleration mechanism; the steer-by-wire execution module includes vehicle components such as a steering wheel, a steering motor, and a deceleration mechanism. In addition, the steer-by-wire system also includes components such as a steering controller and a power supply.

[0036] 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 rotation angle and rotation speed of the steering wheel; the road sensing motor and the deceleration mechanism can provide the driver with the vehicle's motion state, road surface state information and the steering wheel's return torque.

[0037] 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.

[0038] The steering controller is used to determine the rotation angle of the steering wheel based on the rotation angle of the steering wheel, and send a control signal for controlling the steering wheel to rotate the rotation angle to the steering motor, so that the steering motor drives the steering wheel to rotate the rotation angle. In addition, the power supply can be the whole vehicle power supply in the vehicle.

[0039] 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.

[0040] Figure 1 This is an architectural diagram of a front-wheel steer-by-wire system provided in an embodiment of the present application.

[0041] For example, Figure 1 As shown, Figure 1 The front wheel steer-by-wire system of the vehicle shown includes a steering wheel module and a steer-by-wire execution module. The steered wheels in the steer-by-wire execution module are the front wheels of the vehicle. In the event of a failure of the steering wheel module, the vehicle controller in the vehicle obtains the steering angle of the steering wheel determined by the target system through the vehicle controller local area network (CAN) line, determines the steering angle of the front wheel based on the rotation angle, and sends the control signal for controlling the front wheel 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 wheel 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 angle of the steering wheel in the event of a failure of the steering wheel module.

[0042] 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.

[0043] 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 have various faults. For example, the angle sensor in the steering wheel module cannot collect the steering wheel's rotation angle, and the steering motor in the steer-by-wire execution module cannot rotate. In the event of a failure in any device in the front-wheel steer-by-wire system, 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 at this time 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.

[0044] In order to solve the above problems, the present application provides a method for controlling rear wheel steering, so that when the front wheel steer-by-wire system fails, the rear wheels can simulate the front wheel steering to achieve the steering requirements of the vehicle and achieve the same steering effect as the front wheels. Figure 2 The method flow is shown.

[0045] Figure 2 It 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 method for controlling rear wheel steering provided in the embodiment of the present application can be applied to Figure 1 The vehicle shown. Specifically, the method for controlling rear wheel steering can be applied to a target controller in the vehicle, and the target controller is any one of a vehicle controller and a body domain controller in the vehicle. 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 in 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] For example, Figure 2 As shown, the method 200 includes:

[0049] Step 201, when a front wheel steer-by-wire system of a vehicle fails, a 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 the above step 201 can be specifically understood as: a steer-by-wire system in which the steering wheels are the front wheels of the vehicle. The front wheel steer-by-wire system includes a steering wheel module and a steer-by-wire execution module, and also includes a steering controller. In the solution of the present application, the steering controller is specifically a vehicle controller. "Front wheel steer-by-wire system failure" can be specifically understood as: the steering wheel module and / or the steer-by-wire execution module failure.

[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 aforementioned 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, and 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 of times, 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 of times, the vehicle controller determines that the front-wheel steer-by-wire system has a fault.

[0053] It should be understood that in the above scheme, 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. The malfunction of the front wheel steer-by-wire system is often caused by the malfunction of the steering wheel module and / or the steer-by-wire execution module. Therefore, it can be determined whether the front wheel steer-by-wire system has a malfunction by specifically determining whether the number of times the first malfunction status signal sent by the steering wheel module is received within a first preset time period is greater than the first preset number of times; and / or whether the number of times the second malfunction 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 of times.

[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 time length and the second preset time length 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-controlled steering system is not faulty, the vehicle controller determines the steering control amount through the steering 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 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 fail, 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 case of a failure of the steering wheel module, even if the angle sensor does not fail, the steering control amount of the steering wheel can be obtained, but 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. In this way, it can be ensured that in the event of a failure of the steering wheel module in the front-wheel wire-controlled steering system, the steering control amount is obtained, thereby determining the target steering control amount of the rear wheel, and assisting in completing the steering requirements of the vehicle. 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, in the case of a failure of the steering wheel module in the front-wheel steer-by-wire system, the vehicle controller can intervene, and the vehicle controller determines the steering controller of the steering wheel, and determines 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; controls the steering of the rear wheels based on the target steering control amount, etc. In the case that the steering wheel module does not fail, the self-controller (i.e., the steering controller) in the front-wheel steer-by-wire system is used, which can be the determination module mentioned in the device for controlling the steering of the rear wheels above.

[0060] In the above technical solution, the front wheel wire-controlled steering system includes a steering wheel module and a wire-controlled steering execution module, and 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 fail, the various vehicle components in the steering wheel module can work 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 fails, 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 fails.

[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 turning angle of the rear wheels; the target system determines the steering control amount of the steering wheel based on the turning 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, in the case of a failure of the steering wheel module, even if the angle sensor is not faulty and can obtain the steering control amount of the steering wheel, the steering control amount cannot be transmitted to the vehicle controller. Therefore, the present application adopts a visual method to determine the steering control amount of the steering wheel. In this way, it can be ensured that in the case of a failure of the steering wheel module in the front wheel wire control system, the steering control amount can be obtained, thereby determining the target steering control amount of the rear wheel and assisting in completing the steering requirements of the vehicle. Therefore, it 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 a 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; taking 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 at the second position relative to the target reference point at the first position, the first line being the line between the target reference point at the first position and the origin, and the second line being the line between the target reference point at the second position and the origin.

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

[0069] It should also be understood that, generally, the steering wheel is circular in design, and the styles of the steering wheel are double-spoke, three-spoke, four-spoke, etc. Among them, the double-spoke means that there are two spokes on the steering wheel; the three-spoke means that there are three spokes on the steering wheel; and the four-spoke means that there are four spokes on the steering wheel. Therefore, the steering control amount of the steering wheel can be determined by the position change of multiple 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 at the second position relative to the target reference point at the first position, including: when the target reference point at the second position is to the left of the target reference point at the first position, the vehicle controller determines that the direction is counterclockwise; when the target reference point at the second position is to the right of the target reference point at the first position, the vehicle controller determines that the direction is clockwise.

[0071] In one possible implementation, step 201 includes: when a failure occurs in the front-wheel steer-by-wire system, 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 technical solution, in order to improve the stability of the vehicle body during steering, the maximum turning angle value of the rear wheels during steering is often limited. Since the target steering control amount of the rear wheels in this solution is related to the steering control amount of the steering wheel, and the steering control amount is specifically the turning angle value and the turning direction, the maximum turning angle value of the rear wheels during steering can be indirectly limited by controlling the maximum turning angle value of the steering wheel. That is, under the condition of the maximum turning angle value limitation, the steering control amount of the steering wheel is determined in response to the turning operation of the steering wheel. Therefore, the rear wheel steering is controlled based on the target steering control amount, so that the vehicle body remains stable during the steering process and is not prone to loss of 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 rotation angle of the rear wheels is 10 degrees. When the front-wheel steer-by-wire system of the vehicle fails, the vehicle cannot achieve large-angle steering through the rear wheels when the vehicle is traveling at a low speed, but it can also meet the driving needs in low-speed scenarios, for example, it can support vehicle parking. When the front-wheel steer-by-wire system of the vehicle fails, when the vehicle is traveling at high speed, the steering wheel rotation angle value is generally within 180 degrees, the target transmission ratio is 18, and the corresponding rear wheel rotation angle value is within 10 degrees, which can also meet the vehicle's high-speed driving needs.

[0075] Step 202, the vehicle controller determines 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, 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 aforementioned 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 turning angle value of the steering wheel increases. This is for vehicle safety considerations.

[0078] In a 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 is specifically the distance between the front wheel and the rear wheel on the same side. "Yaw angular velocity" refers to the deflection of the wheels in the vehicle around the vertical axis, which 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 scheme are used to refer to the turning angle of the wheels in general, 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 travel 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]

[0085] Among them, ω1 is the yaw angular velocity of the front wheel, 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.

[0086] 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);

[0087]

[0088] 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.

[0089] 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 yaw direction value as 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, the first numerical value being a numerical value used to indicate the positive or negative yaw angular velocity of the front wheel, and the second numerical value being a numerical value used to indicate the positive or negative yaw angular velocity of the rear wheel.

[0090] It should be understood that in the actual driving process, the direction of the yaw angular velocity of the front wheel is different from the direction of the yaw angular velocity of the rear wheel. Therefore, in the process of simulating the front wheel steering by the rear wheel, in order to achieve the same steering effect as the front wheel steering, the influence of the yaw angular velocity needs to be considered. In this regard, the present application introduces the yaw direction value in the process of determining the target steering control amount of the rear wheel, so that when the rear wheel is turned with the target steering control amount, the same steering effect as the front wheel is achieved, which is in line with the steering habits of the vehicle user.

[0091] In one possible implementation, the method 200 also includes: the vehicle controller detects whether a rear-wheel steering system in the vehicle fails; when the rear-wheel steering system does not fail, the vehicle controller executes 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.

[0092] In the above technical solution, it is equivalent to detecting whether the rear wheel steering system in the vehicle fails before the vehicle is turned by the rear wheels. The target steering control amount of the rear wheels is determined only when the rear wheel steering system does not fail. This solution can avoid the process of determining the target steering control amount when the rear wheel steering system fails, which can avoid the problem of wasting computing resources.

[0093] Step 203: The vehicle controller controls the rear wheel steering based on the target steering control amount.

[0094] In one possible implementation, step 203 includes: the vehicle controller determines the target direction and the target angle value of the rear wheel when the rear wheel rotates based on the target steering control amount; the vehicle controller controls the rear wheel to rotate toward the target direction by the target angle value.

[0095] In the above technical solution, usually before determining the rotation of the wheel, it is necessary to determine the rotation direction and rotation angle (value) of the wheel. Therefore, the solution determines 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 then controls the rear wheel to rotate to the target direction by the target angle value. In other words, in the event of a failure of the front wheel steer-by-wire system, the rear wheel is rotated to achieve the same effect as the front wheel rotation, so as to meet the steering needs of the user on the vehicle and meet the steering habits of the vehicle user.

[0096] In some embodiments, the vehicle controller determines the target direction and the target angle value of the rear wheel when the rear wheel turns 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.

[0097] 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.

[0098] In the above technical solution, after the vehicle controller determines that the rear wheel steering needs to be controlled based on the target steering control amount, the vehicle controller controls the vehicle to output the reminder information, so as to remind the user on the vehicle that the vehicle is steering through the rear wheels and to remind the user on the vehicle to adjust the sitting posture to avoid collision.

[0099] Figure 3 It is a block diagram of a method for controlling rear wheel steering provided in an embodiment of the present application.

[0100] An exemplary example is Figure 3 As shown, if the first fault status signal sent by the steering wheel module in the front-wheel steering-by-wire system of the vehicle is not received within a first preset time period, but the number of times the second fault status signal sent by the steering-by-wire execution module in the front-wheel steering-by-wire system is received within a second preset time period is greater than the second preset number, the vehicle controller determines that the steering-by-wire execution module has a fault, the front-wheel steering-by-wire system has a fault, and the vehicle cannot be steered by 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 velocity when the front wheel in the vehicle rotates 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 velocity when the rear wheel in the vehicle rotates 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 velocity and the rear wheel yaw velocity, and the yaw direction value is a value used to indicate that the rotation direction of the rear wheel is opposite to the rotation direction of the front wheel when the steering wheel is rotated in the target direction; the vehicle controller determines the target steering control amount of the rear wheel based on the steering control amount, the target transmission ratio between the steering wheel and the front wheel, and the yaw direction value; the vehicle controller determines 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. The vehicle controller sends the target direction and the target angle value of the rear wheel when the rear wheel rotates 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.

[0101] Another exemplary example is Figure 3As shown, when the vehicle controller receives the first fault status signal sent by the steering wheel module in the front-wheel steering-by-wire system of the vehicle more than the first preset number of times within the first preset time period, the vehicle controller determines that the steering wheel module has failed, the front-wheel steering-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 velocity 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 velocity 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 velocity and the rear wheel yaw velocity, and the yaw direction value is a 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 turned 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 when the rear wheel rotates 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.

[0102] Figure 4 This is a scene diagram for controlling rear wheel steering provided in an embodiment of the present application.

[0103] For example, Figure 4 As shown, in the case where the front wheel steer-by-wire 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 clockwise, the vehicle controller determines the target rotation angle value of the rear wheels in the vehicle based on the steering control amount and the target transmission ratio between the steering wheel and the front wheels. The vehicle controller controls the rear wheels to rotate counterclockwise to the target rotation angle value. Corresponding to the aforementioned method 200, in Figure 4 In the illustrated embodiment, the target steering control amount in the method 200 includes a target direction when the rear wheel rotates being a counterclockwise direction, and a target angle value when the rear wheel rotates being a target rotation angle value.

[0104] Figure 5 It is a structural schematic diagram of a device for controlling rear wheel steering provided in an embodiment of the present application.

[0105] For example, Figure 5 As shown, the device 500 includes:

[0106] The determination module 501 is used to:

[0107] 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 of 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 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 a target direction;

[0108] The control module 502 is used to control the rear wheel steering based on the target steering control amount.

[0109] 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 of times; 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 of times.

[0110] Optionally, the determination module 501 is further specifically used for: when the steering wheel module in the front-wheel wire-controlled steering system is not faulty, determining the steering control amount by means of a steering angle sensor in the steering wheel module; when the steering wheel module fails, acquiring the steering control amount from a target system via the controller area network of the vehicle, and the target system is used to determine the steering control amount.

[0111] Optionally, the determination module 501 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 of the first angle and the yaw direction value as the target steering control amount.

[0112] Optionally, the determination module 501 is also used to determine the target direction and target angle value of the rear wheel when the rear wheel rotates 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 by the target angle value.

[0113] 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 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.

[0114] 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.

[0115] Figure 6 It is a structural schematic diagram of a vehicle provided in an embodiment of the present application.

[0116] For example, Figure 6 As shown, 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.

[0117] In this embodiment, the functional modules of the vehicle can be divided according to the above method example. For example, each functional module can be corresponded, or two or more functions can be integrated into one processing module. The above integrated module can be implemented in the form of hardware. It should be noted that the division of modules in this embodiment is schematic and is only a logical function division. There may be other division methods in actual implementation.

[0118] In the case of dividing each functional module according to each function, 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, which will not be repeated here.

[0119] 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.

[0120] 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 actions of the vehicle. The storage module may be used for the vehicle to execute mutual program codes and data.

[0121] The processing module may be a processor or a controller, which may implement or execute various exemplary logic blocks, modules and circuits disclosed in the present application. The processor may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of digital signal processing (DSP) and a microprocessor, etc. The storage module may be a memory.

[0122] This embodiment provides a computer-readable storage medium, in which instructions are stored. When the instructions are executed on a computer or a processor, the computer or the processor executes any one of the methods for controlling rear wheel steering described above.

[0123] This embodiment also provides a computer program product including instructions. When the computer program product is executed on a computer or a processor, the computer or the processor executes the above-mentioned related steps to implement any one of the methods for controlling rear wheel steering described above.

[0124] 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.

[0125] 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 assigned to 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.

[0126] In the embodiments provided in the present 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 only schematic, for example, the division of modules or units is only a logical function division, and there may be other division methods in actual implementation, 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.

[0127] The above contents are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope 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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