Vehicle control method, vehicle and storage medium

Abstract

The present application belongs to the technical field of vehicles. Disclosed are a vehicle control method, a vehicle and a storage medium. The method comprises: when a steering wheel of a target vehicle keeps centered and rear wheels of the target vehicle exhibit abnormal steering, determining a target front wheel steering angle on the basis of the difference between the current rear wheel steering angle and a target rear wheel steering angle of the target vehicle and vehicle parameters, the target rear wheel steering angle being the angle of the rear wheels of the target vehicle in a centered state, and the target front wheel steering angle being an angle by which the front wheels of the target vehicle should turn to compensate for the abnormal steering of the rear wheels; on the basis of the target front wheel angle, determining target compensation torque; and controlling a front wheel motor of the target vehicle to output the target compensation torque, so as to adjust the front wheel angle of the target vehicle to keep the target vehicle in a straight driving state. In this way, outputting the target compensation torque by means of the front wheel motor can compensate for a trajectory deviation caused by the abnormal steering of the rear wheels, such that the target vehicle can keep traveling in a straight line, thereby improving driving safety.

Description

Vehicle control methods, vehicles and storage media

[0001] This application claims priority to Chinese patent application filed on November 27, 2024, with application number 202411717102.5 and entitled "Vehicle Control Method, Apparatus and Vehicle", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of vehicle technology, and in particular to a vehicle control method, a vehicle, and a storage medium. Background Technology

[0003] To enhance the driving experience, most vehicles nowadays are equipped with rear-wheel steering systems. During steering, both the front and rear wheels turn together, increasing the functionality of the steering system and improving steering responsiveness. Normally, when a vehicle is traveling in a straight line, the steering wheel is in the center position, and both the front and rear wheels are also in the center position, meaning both the front and rear wheel steering angles are 0 degrees.

[0004] However, when the rear-wheel steering system malfunctions, the rear wheels may exhibit unexpected steering problems while the vehicle is traveling in a straight line. That is, while the vehicle should be maintaining a centered position, the rear wheels may turn at an angle due to the malfunction. Generally, when the rear wheels turn left or right, the yaw rate of the entire vehicle increases, making the vehicle unstable and increasing driving risks. Therefore, a vehicle control method is urgently needed to solve the rear-wheel steering problem that occurs when the vehicle is traveling in a straight line. Summary of the Invention

[0005] This application provides a vehicle control method, a vehicle, and a storage medium. When the rear wheels exhibit abnormal steering during straight-line driving, a compensating torque is output from the front wheel motor. This torque is used to compensate for the trajectory deviation caused by the abnormal steering of the rear wheels, ensuring the vehicle maintains straight-line driving even when the rear wheels exhibit abnormal steering, thereby improving driving safety. The technical solution includes the following:

[0006] Firstly, a vehicle control method is provided, the method comprising:

[0007] When the steering wheel of the target vehicle is kept in the center and the rear wheels of the target vehicle exhibit abnormal steering, the target front wheel steering angle is determined based on the difference between the current rear wheel steering angle and the target rear wheel steering angle, as well as the vehicle parameters. The target rear wheel steering angle is the angle of the rear wheels of the target vehicle when they are in the center state, and the target front wheel steering angle is the angle that the front wheels of the target vehicle should rotate to compensate for the abnormal steering of the rear wheels. The vehicle parameters include dynamic vehicle parameters and static vehicle parameters.

[0008] Determine the target compensation torque based on the target front wheel steering angle;

[0009] Control the front wheel motor of the target vehicle to output the target compensation torque, so as to keep the target vehicle in a straight-line driving state by adjusting the front wheel angle.

[0010] In this application, when the steering wheel of the target vehicle remains centered and the rear wheels of the target vehicle exhibit abnormal steering, the target front wheel steering angle is first determined based on the difference between the current rear wheel steering angle and the target rear wheel steering angle, as well as vehicle parameters. This determines the angle at which the front wheels of the target vehicle should rotate to compensate for the abnormal steering of the rear wheels. Then, based on the target front wheel steering angle, the target compensation torque is determined, i.e., the torque that the front wheels should compensate for. Finally, the front wheel motor of the target vehicle is controlled to output the target compensation torque to maintain the target vehicle in a straight-line driving state by adjusting the front wheel angle. This application, when the rear wheels of the target vehicle exhibit abnormal steering while the vehicle is driving straight, controls the front wheels to rotate by a certain angle by outputting the target compensation torque from the front wheel motor. This compensates for the trajectory deviation caused by the abnormal steering of the rear wheels, thereby maintaining the target vehicle in a straight-line driving state and improving driving safety.

[0011] Optionally, when the steering wheel of the target vehicle remains centered and the rear wheels of the target vehicle exhibit abnormal steering, before determining the target front wheel steering angle based on the difference between the current rear wheel steering angle and the target rear wheel steering angle, as well as vehicle parameters, the following steps are also included:

[0012] Obtain the target vehicle's current steering wheel angle, current rear wheel angle, target rear wheel angle, and current yaw rate;

[0013] Based on the current steering wheel angle, current rear wheel angle, target rear wheel angle, and current yaw rate, determine whether the target vehicle's steering wheel remains centered and whether the target vehicle's rear wheels exhibit abnormal steering.

[0014] Optionally, based on the current steering wheel angle, current rear wheel angle, target rear wheel angle, and current yaw rate, determine whether the target vehicle's steering wheel remains centered and whether the target vehicle's rear wheels exhibit abnormal steering, including:

[0015] Subtract the target rear wheel angle from the current rear wheel angle to obtain the rear wheel angle difference;

[0016] If the current steering wheel angle is less than or equal to the preset steering wheel angle threshold, the rear wheel angle difference is greater than or equal to the preset difference threshold, and the current yaw rate is greater than or equal to the preset yaw rate threshold, then the steering wheel of the target vehicle is determined to remain centered and the rear wheels of the target vehicle are found to be abnormally turning.

[0017] If the current steering wheel angle is less than or equal to the preset steering wheel angle threshold, the difference in rear wheel angle is less than the preset difference threshold, and the current yaw rate is less than the preset angular rate threshold, then the steering wheel of the target vehicle remains centered and the rear wheels of the target vehicle do not exhibit abnormal steering.

[0018] Optionally, static vehicle parameters include the axle attributes of the target vehicle, and dynamic vehicle parameters include the current driving parameters of the target vehicle. Based on the difference between the current rear wheel steering angle and the target rear wheel steering angle, and the vehicle parameters, the target front wheel steering angle is determined, including:

[0019] The target front wheel angle is determined based on the difference between the current rear wheel angle and the target rear wheel angle of the target vehicle, the axle attributes, and the current driving parameters.

[0020] Optionally, the axle attributes include front axle lateral stiffness and rear axle lateral stiffness, and the current driving parameters include the current vehicle speed. Based on the difference between the current rear wheel steering angle and the target rear wheel steering angle, the axle attributes, and the current driving parameters, the target front wheel steering angle is determined, including:

[0021] Based on the current vehicle speed, a first compensation coefficient is determined. The first compensation coefficient is used to represent the ratio between the front wheel angle and the rear wheel angle of the target vehicle at the current vehicle speed.

[0022] Based on the front axle lateral stiffness and the rear axle lateral stiffness, a second compensation coefficient is determined. The second compensation coefficient is used to represent the inherent angle ratio between the front wheel angle and the rear wheel angle of the target vehicle.

[0023] Based on the first compensation coefficient, the second compensation coefficient, and the rear wheel angle difference, the target front wheel angle is determined, and the rear wheel angle difference is the difference between the current rear wheel angle of the target vehicle and the target rear wheel angle.

[0024] Optionally, the axle attributes also include front axle suspension elasticity and rear axle suspension elasticity. Based on the front axle lateral stiffness and rear axle lateral stiffness, a second compensation coefficient is determined, including:

[0025] The second compensation coefficient is determined based on the front axle lateral stiffness, rear axle lateral stiffness, front axle suspension elasticity, and rear axle suspension elasticity.

[0026] Optionally, a second compensation coefficient is determined based on the front axle lateral stiffness, rear axle lateral stiffness, front axle suspension elasticity, and rear axle suspension elasticity, including:

[0027] Divide the front axle side stiffness by the rear axle side stiffness to obtain the first reference coefficient.

[0028] Divide the rear axle suspension stiffness by the front axle suspension stiffness to obtain the second reference coefficient;

[0029] Multiply the first reference coefficient by the second reference coefficient to obtain the second compensation coefficient.

[0030] Optionally, the target front wheel steering angle is determined based on the first compensation coefficient, the second compensation coefficient, and the rear wheel steering angle difference, including:

[0031] Multiply the first compensation coefficient by the second compensation coefficient to obtain the target compensation coefficient;

[0032] Multiply the difference in rear wheel steering angle by the target compensation coefficient to obtain the target front wheel steering angle.

[0033] Optionally, before determining the target compensation torque based on the target front wheel steering angle, the method further includes:

[0034] The current speed, current steering wheel torque, and steering system stiffness of the target vehicle are obtained. Steering system stiffness refers to the ability of the target vehicle's steering system to resist deformation.

[0035] Based on the target front wheel steering angle, determine the target compensation torque, including:

[0036] The target compensation torque is determined based on the target front wheel angle, current vehicle speed, current steering wheel torque, and steering system stiffness.

[0037] Optionally, the target compensation torque is determined based on the target front wheel steering angle, current vehicle speed, current steering wheel torque, and steering system stiffness, including:

[0038] Based on the current vehicle speed, the target assist coefficient is determined. The target assist coefficient refers to the ratio between the torque provided by the steering system when controlling the front wheel steering at the current vehicle speed and the torque applied by the driver.

[0039] Multiply the target assist coefficient by the current steering wheel torque to obtain the first assist torque;

[0040] Multiply the target front wheel steering angle by the steering system stiffness to obtain the second assist torque;

[0041] The sum of the first assist torque and the second assist torque is determined as the target compensation torque.

[0042] Optionally, based on the current vehicle speed, the target assist coefficient is determined, including:

[0043] When the current vehicle speed is less than or equal to the target vehicle speed threshold, the target assist coefficient is determined as the first coefficient. The first coefficient is the target assist coefficient when the target vehicle is traveling at low speed.

[0044] When the current vehicle speed is greater than the target vehicle speed threshold, the target assist coefficient is determined as the second coefficient, which is the target assist coefficient when the target vehicle is traveling at high speed.

[0045] Optionally, the method further includes:

[0046] The target assist torque is obtained by adding the target compensation torque to the current assist torque of the assist motor of the target vehicle. The assist motor is the motor controlled by the electric power steering system of the target vehicle.

[0047] Control the power assist motor of the target vehicle to output the target assist torque in order to adjust the front wheel angle of the target vehicle.

[0048] Optionally, the target assist torque is obtained by adding the target compensation torque to the current assist torque of the target vehicle's assist motor, including:

[0049] Obtain the first weight corresponding to the target compensation torque;

[0050] Obtain the second weight corresponding to the current assist torque;

[0051] Based on the first and second weights, the target compensation torque and the current assist torque are weighted and summed to obtain the target assist torque.

[0052] Secondly, a vehicle control device is provided, the device comprising:

[0053] The first determining module is used to determine the target front wheel angle based on the difference between the current rear wheel angle and the target rear wheel angle, as well as vehicle parameters, when the steering wheel of the target vehicle is kept in the center and the rear wheels of the target vehicle exhibit abnormal steering. The target rear wheel angle is the angle of the rear wheels of the target vehicle when they are in the center state, and the target front wheel angle is the angle that the front wheels of the target vehicle should rotate to compensate for the abnormal steering of the rear wheels. The vehicle parameters include dynamic vehicle parameters and static vehicle parameters.

[0054] The second determining module is used to determine the target compensation torque based on the target front wheel steering angle;

[0055] The torque output module is used to control the front wheel motor of the target vehicle to output the target compensation torque, so as to keep the target vehicle in a straight-line driving state by adjusting the front wheel angle.

[0056] Optionally, the device further includes:

[0057] The first acquisition module is used to acquire the target vehicle's current steering wheel angle, current rear wheel angle, target rear wheel angle, and current yaw rate;

[0058] The third determining module is used to determine whether the steering wheel of the target vehicle remains centered and whether the rear wheels of the target vehicle exhibit abnormal steering based on the current steering wheel angle, the current rear wheel angle, the target rear wheel angle, and the current yaw rate.

[0059] Optionally, the third determining module is used for:

[0060] Subtract the target rear wheel angle from the current rear wheel angle to obtain the rear wheel angle difference;

[0061] If the current steering wheel angle is less than or equal to the preset steering wheel angle threshold, the rear wheel angle difference is greater than or equal to the preset difference threshold, and the current yaw rate is greater than or equal to the preset yaw rate threshold, then the steering wheel of the target vehicle is determined to remain centered and the rear wheels of the target vehicle are found to be abnormally turning.

[0062] If the current steering wheel angle is less than or equal to the preset steering wheel angle threshold, the difference in rear wheel angle is less than the preset difference threshold, and the current yaw rate is less than the preset angular rate threshold, then the steering wheel of the target vehicle remains centered and the rear wheels of the target vehicle do not exhibit abnormal steering.

[0063] Optionally, static vehicle parameters include the axle attributes of the target vehicle, and dynamic vehicle parameters include the current driving parameters of the target vehicle. The first determining module is used for:

[0064] The target front wheel angle is determined based on the difference between the current rear wheel angle and the target rear wheel angle of the target vehicle, the axle attributes, and the current driving parameters.

[0065] Optionally, the axle attributes include front axle lateral stiffness and rear axle lateral stiffness, and the current driving parameters include the current vehicle speed. The first determining module is used for:

[0066] Based on the current vehicle speed, a first compensation coefficient is determined. The first compensation coefficient is used to represent the ratio between the front wheel angle and the rear wheel angle of the target vehicle at the current vehicle speed.

[0067] Based on the front axle lateral stiffness and the rear axle lateral stiffness, a second compensation coefficient is determined. The second compensation coefficient is used to represent the inherent angle ratio between the front wheel angle and the rear wheel angle of the target vehicle.

[0068] Based on the first compensation coefficient, the second compensation coefficient, and the rear wheel angle difference, the target front wheel angle is determined, and the rear wheel angle difference is the difference between the current rear wheel angle of the target vehicle and the target rear wheel angle.

[0069] Optionally, the axle attributes also include front axle suspension elasticity and rear axle suspension elasticity, and the first determining module is further used for:

[0070] The second compensation coefficient is determined based on the front axle lateral stiffness, rear axle lateral stiffness, front axle suspension elasticity, and rear axle suspension elasticity.

[0071] Optionally, the first determining module is also specifically used for:

[0072] Divide the front axle side stiffness by the rear axle side stiffness to obtain the first reference coefficient.

[0073] Divide the rear axle suspension stiffness by the front axle suspension stiffness to obtain the second reference coefficient;

[0074] Multiply the first reference coefficient by the second reference coefficient to obtain the second compensation coefficient.

[0075] Optionally, the first determining module is used for:

[0076] Multiply the first compensation coefficient by the second compensation coefficient to obtain the target compensation coefficient;

[0077] Multiply the difference in rear wheel steering angle by the target compensation coefficient to obtain the target front wheel steering angle.

[0078] Optionally, the device further includes:

[0079] The second acquisition module is used to acquire the target vehicle's current speed, current steering wheel torque, and steering system stiffness, which refers to the target vehicle's steering system's ability to resist deformation.

[0080] Optionally, the second determining module is used for:

[0081] The target compensation torque is determined based on the target front wheel angle, current vehicle speed, current steering wheel torque, and steering system stiffness.

[0082] Optionally, the second determining module is used for:

[0083] Based on the current vehicle speed, the target assist coefficient is determined. The target assist coefficient refers to the ratio between the torque provided by the steering system when controlling the front wheel steering at the current vehicle speed and the torque applied by the driver.

[0084] Multiply the target assist coefficient by the current steering wheel torque to obtain the first assist torque;

[0085] Multiply the target front wheel steering angle by the steering system stiffness to obtain the second assist torque;

[0086] The sum of the first assist torque and the second assist torque is determined as the target compensation torque.

[0087] Optionally, the second determining module is specifically used for:

[0088] When the current vehicle speed is less than or equal to the target vehicle speed threshold, the target assist coefficient is determined as the first coefficient. The first coefficient is the target assist coefficient when the target vehicle is traveling at low speed.

[0089] When the current vehicle speed is greater than the target vehicle speed threshold, the target assist coefficient is determined as the second coefficient, which is the target assist coefficient when the target vehicle is traveling at high speed.

[0090] Optionally, the torque output module is also used for:

[0091] The target assist torque is obtained by adding the target compensation torque to the current assist torque of the assist motor of the target vehicle. The assist motor is the motor controlled by the electric power steering system of the target vehicle.

[0092] Control the power assist motor of the target vehicle to output the target assist torque in order to adjust the front wheel angle of the target vehicle.

[0093] Optionally, the torque output module is also used for:

[0094] Obtain the first weight corresponding to the target compensation torque;

[0095] Obtain the second weight corresponding to the current assist torque;

[0096] Based on the first and second weights, the target compensation torque and the current assist torque are weighted and summed to obtain the target assist torque.

[0097] Thirdly, a vehicle is provided, the vehicle comprising:

[0098] Memory, used to store executable program code;

[0099] The processor is used to call and run executable program code from memory, so that the vehicle performs the vehicle control methods described above.

[0100] Fourthly, a computer-readable storage medium is provided, the computer-readable storage medium storing a computer program, which, when executed by a processor, implements the above-described vehicle control method.

[0101] Fifthly, a computer program product containing instructions is provided, which, when run on a computer, causes the computer to perform the steps of the vehicle control method described above.

[0102] It is understood that the beneficial effects of the second, third, fourth, and fifth aspects mentioned above can be found in the relevant descriptions in the first aspect above, and will not be repeated here. Attached Figure Description

[0103] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0104] Figure 1 is a schematic diagram of the implementation environment of a vehicle control method provided in an embodiment of this application;

[0105] Figure 2 is a schematic diagram of a vehicle control method provided in an embodiment of this application;

[0106] Figure 3 is a flowchart of a vehicle control method provided in an embodiment of this application;

[0107] Figure 4 is a flowchart of determining a target assist torque according to an embodiment of this application;

[0108] Figure 5 is a flowchart of another vehicle control method provided in an embodiment of this application;

[0109] Figure 6 is a structural schematic diagram of a vehicle control device provided in an embodiment of this application;

[0110] Figure 7 is a structural schematic diagram of a vehicle provided in an embodiment of this application. Embodiments of the present invention

[0111] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0112] It should be understood that "multiple" as mentioned in this application refers to two or more. In the description of this application, unless otherwise stated, " / " indicates "or," for example, A / B can mean A or B; "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist, for example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, to facilitate a clear description of the technical solutions of this application, the terms "first," "second," etc., are used to distinguish identical or similar items with essentially the same function and effect. Those skilled in the art will understand that the terms "first," "second," etc., do not limit the quantity or execution order, and that "first," "second," etc., do not necessarily imply differences.

[0113] The application scenarios of the embodiments of this application will be explained first.

[0114] Figure 1 is a schematic diagram of the implementation environment of a vehicle control method provided in an embodiment of this application. Referring to Figure 1, Figure 1 includes a vehicle 101, which is equipped with an electric power steering system 102 (EPS) and a rear-wheel steering system 103.

[0115] Vehicle 101 is a vehicle equipped with the aforementioned rear-wheel steering system 103. For example, vehicle 101 can be a front-wheel drive (FWD), a rear-wheel drive (RWD), or an all-wheel drive (AWD) vehicle. This application embodiment does not limit the type of vehicle 101.

[0116] The electric power steering system 102 is a power steering system that directly relies on an electric motor to provide auxiliary torque. It assists the driver, reducing the force required for steering. Typically, the electric power steering system 102 calculates the required amount of assistance by detecting the steering wheel angle and vehicle speed. It then controls the front wheel motors to rotate and output the corresponding torque to automatically adjust the front wheel angle to provide steering assistance, thus saving the driver's effort on the steering wheel. Generally, when the vehicle is traveling at low speeds, especially when turning, the electric power steering system 102 can provide greater assistance, making steering easier.

[0117] The rear-wheel steering system 103 is a technology that can adjust the direction angle of the rear wheels. It improves vehicle handling performance by allowing the rear wheels to rotate in the same direction or opposite direction relative to the front wheels under certain conditions. The rear-wheel steering system 103 consists of a rear-wheel steering controller and a steer-by-wire system. It receives steering wheel angle and speed signals from the vehicle controller via wires, and then calculates the required rotation angle based on these signals. Under normal straight-line driving conditions, the rear wheels should remain straight to prevent the vehicle from veering off course. When turning at low speeds, the rear wheels can rotate in the opposite direction to reduce the turning radius; when changing lanes at high speeds, the rear wheels rotate in the same direction as the front wheels to improve vehicle stability.

[0118] In this embodiment of the application, if the rear wheel steering system 103 malfunctions during the straight-line driving of the vehicle 101, the rear wheels will steer abnormally. At this time, the electric power steering system 102 can compensate for the trajectory deviation caused by the abnormal steering of the rear wheels, thereby keeping the vehicle 101 in a straight-line driving position.

[0119] The application scenarios of the embodiments of this application will be described below.

[0120] For example, Figure 2 is a schematic diagram of a vehicle control method provided in an embodiment of this application. Referring to Figure 2, the vehicle 201 is included and the vehicle 201 is traveling in a straight line.

[0121] During the movement of vehicle 201, the electric power steering system 102 and the rear-wheel steering system 103 acquire the steering wheel angle of vehicle 201. When maintaining straight-line driving, the steering wheel angle is 0, therefore the electric power steering system 102 and the rear-wheel steering system 103 determine the front wheel angle and rear wheel angle to be 0 based on the steering wheel angle. During the movement of vehicle 201, the front wheel angle and the rear wheel angle can be controlled to be 0. As shown in Figure 2, vehicle 201 can travel along trajectory A.

[0122] However, if the rear-wheel steering system 103 malfunctions, the rear wheel angle, which should be 0 when the vehicle 201 is traveling straight, may become skewed due to the malfunction. This is known as unintended rear-wheel steering, causing the vehicle 201 to deviate from its original trajectory. As shown in Figure 2, when the rear wheels turn unexpectedly, the vehicle 201 may travel along trajectory B. In this situation, turning the rear wheels to the left or right increases the yaw rate of the entire vehicle, making it unstable and increasing the risk of accidents.

[0123] Therefore, this application provides a vehicle control method that can be applied to scenarios where a vehicle needs to maintain straight-line travel. For example, the vehicle control method can be applied to scenarios where a vehicle needs to travel straight on a narrow road, or to scenarios where a vehicle needs to travel straight on a narrow bridge.

[0124] Specifically, the vehicle control method provided in this application embodiment will be described using the scenario shown in Figure 2 above. During the straight-line driving of vehicle 201, the steering wheel of vehicle 201 remains centered. However, at this time, the rear wheels of vehicle 201 exhibit abnormal steering. First, based on the difference between the current rear wheel steering angle and the target rear wheel steering angle, and the vehicle parameters, a front wheel steering angle is determined. This front wheel steering angle is the angle at which the front wheels of vehicle 201 should rotate to compensate for the abnormal steering of the rear wheels. Then, based on this front wheel steering angle, a compensation torque is determined, that is, the torque that the front wheels should compensate for. Finally, the front wheel motor of vehicle 201 is controlled to output this compensation torque.

[0125] Thus, when the rear wheels of vehicle 201 veer abnormally while it is traveling in a straight line, the front wheel motor outputs a certain amount of compensating torque to control the front wheels to rotate at a certain angle. This can compensate for the trajectory deviation caused by the abnormal steering of the rear wheels, thereby keeping vehicle 201 in a straight-line state even when the rear wheels veer abnormally, thus improving driving safety.

[0126] The vehicle control method provided in the embodiments of this application will be explained in detail below.

[0127] Figure 3 is a flowchart of a vehicle control method provided in an embodiment of this application. This method can be applied to the vehicle control unit (VCU). Referring to Figure 3, the method includes the following steps.

[0128] Step 301: When the steering wheel of the target vehicle is kept in the center and the rear wheels of the target vehicle exhibit abnormal steering, the target front wheel steering angle is determined based on the difference between the current rear wheel steering angle and the target rear wheel steering angle, as well as vehicle parameters, including dynamic vehicle parameters and static vehicle parameters.

[0129] The current rear wheel rotation angle refers to the angle at which the rear wheels of the target vehicle are rotating at the current moment.

[0130] The target rear wheel steering angle is the angle of the target vehicle's rear wheels when they are in the center position. In this embodiment, the target rear wheel steering angle can be the requested rear wheel steering angle, that is, the angle at which the target vehicle requests the rear wheels to turn. Therefore, when the target vehicle's steering wheel is kept in the center position, the steering wheel angle is also 0. Thus, in this case, the requested rear wheel steering angle should also be 0, which is the angle of the rear wheels when they are in the center position.

[0131] It should be understood that the target vehicle's control of the front and rear wheel angles is performed on a cyclical basis. That is, the current steering wheel angle is acquired at preset intervals, the front and rear wheel angles are calculated, and the calculated front wheel angle is used to control the front wheel response, and the calculated rear wheel angle is used to control the rear wheel response. In this case, the target rear wheel angle can also be the rear wheel angle from the previous cycle. Furthermore, if abnormal rear wheel steering is determined in the current cycle, the rear wheel angle in the current cycle will necessarily be different from the rear wheel angle in the previous cycle. Therefore, when abnormal steering occurs, the target rear wheel angle can also be the rear wheel angle from the previous cycle.

[0132] The target front wheel steering angle is the angle that the front wheels of the target vehicle should rotate to compensate for abnormal steering of the rear wheels.

[0133] The vehicle parameters can include dynamic vehicle parameters and static vehicle parameters. Dynamic vehicle parameters refer to vehicle parameters that change as the target vehicle moves, such as vehicle speed, engine speed, and output torque. Static vehicle parameters indicate vehicle parameters that do not change with the target vehicle's movement; these are the inherent vehicle parameters of the target vehicle, such as the front axle lateral stiffness, wheelbase, and weight.

[0134] In this embodiment of the application, the difference between the current rear wheel angle and the target rear wheel angle of the target vehicle can be used to determine how much the rear wheels of the target vehicle have rotated, and thus the amount of angle that the front wheels should compensate can be determined.

[0135] In this scenario, the target front wheel angle is determined based on the difference between the current rear wheel steering angle and the target rear wheel steering angle, along with vehicle parameters. This allows us to determine the angle the front wheels should compensate for when the rear wheels exhibit abnormal steering during the vehicle's operation. Furthermore, when abnormal rear wheel steering occurs, compensating with a certain angle from the front wheels can correct the trajectory deviation caused by the abnormal rear wheel steering, enabling the target vehicle to continue traveling in a straight line.

[0136] In this embodiment, static vehicle parameters may include the axle attributes of the target vehicle, and dynamic vehicle parameters may include the current driving parameters of the target vehicle. In this case, step 301 can be performed by: determining the target front wheel angle based on the difference between the current rear wheel angle and the target rear wheel angle, the axle attributes, and the current driving parameters.

[0137] Axle attributes refer to information related to the axles of a target vehicle, such as axle length, axle weight, wheelbase, front axle lateral stiffness, rear axle lateral stiffness, and suspension elasticity.

[0138] Since the steering angle of the front wheels is greatly affected by the axle and driving parameters when the wheels are turning, the target front wheel steering angle can be determined by referring to the axle attributes and the current driving parameters.

[0139] In this case, the target front wheel angle is determined by combining the inherent vehicle parameters and dynamic driving parameters of the target vehicle, based on the difference between the current rear wheel angle and the target rear wheel angle, the axle attributes, and the current driving parameters. This can improve the accuracy of the target front wheel angle.

[0140] As one implementation, the axle attributes may include the front axle lateral stiffness and the rear axle lateral stiffness, and the current driving parameters may include the current vehicle speed. In this case, the operation of determining the target front wheel angle based on the difference between the current rear wheel angle and the target rear wheel angle of the target vehicle, the axle attributes, and the current driving parameters may include the following steps (1)-(3).

[0141] (1) Determine the first compensation coefficient based on the current vehicle speed.

[0142] The first compensation coefficient is used to represent the ratio between the front wheel angle and the rear wheel angle of the target vehicle at the current speed.

[0143] Because the angle of wheel rotation is affected by vehicle speed when turning, for example, the higher the vehicle speed, the larger the rotation angle needs to be to achieve a fast turn. Therefore, a first compensation coefficient can be determined based on the current vehicle speed. This establishes a ratio between the front wheel angle and the rear wheel angle at a given vehicle speed during operation.

[0144] Optionally, step (1) can be performed as follows: based on the current vehicle speed, obtain the corresponding compensation coefficient from the first correspondence and determine it as the first compensation coefficient.

[0145] The first correspondence is the correspondence between vehicle speed and compensation coefficient. The first correspondence includes multiple vehicle speeds and multiple compensation coefficients. The multiple vehicle speeds and multiple compensation coefficients correspond one-to-one, that is, any one of the multiple vehicle speeds has a corresponding compensation coefficient.

[0146] For example, Table 1 below shows an example of the first correspondence. Table 1 includes multiple vehicle speeds and multiple compensation coefficients, and the multiple vehicle speeds and multiple compensation coefficients correspond one-to-one. For example, if the current vehicle speed is 40, then from Table 1 below, the first compensation coefficient can be determined to be 0.3.

[0147] Table 1

[0148]

[0149] The embodiments of this application are merely illustrative examples of the first correspondence relationship described in Table 1 above, and do not constitute a limitation on the embodiments of this application.

[0150] (2) Determine the second compensation coefficient based on the front axle lateral stiffness and the rear axle lateral stiffness.

[0151] The second compensation coefficient is used to represent the inherent angle ratio between the front wheel angle and the rear wheel angle of the target vehicle.

[0152] The first compensation coefficient considers the ratio between the front and rear wheel angles at the current vehicle speed. However, the target vehicle's steering performance is also related to fixed parameters such as the front and rear axles. Typically, the most relevant parameters are the front and rear axle lateral stiffness, which affect the vehicle's roll during steering, thus impacting steering stability. Therefore, a second compensation coefficient can be determined based on the front and rear axle lateral stiffness.

[0153] Optionally, step (2) can be performed by dividing the front axle side stiffness by the rear axle side stiffness to obtain the second compensation coefficient.

[0154] In this case, the second compensation coefficient is positively correlated with the front axle lateral stiffness and negatively correlated with the rear axle lateral stiffness.

[0155] In this embodiment, the axle attributes may further include suspension elasticity. That is, the target vehicle's steering performance is also related to the front axle suspension elasticity and the rear axle suspension elasticity. In this case, the step of determining the second compensation coefficient may further include: dividing the rear axle suspension elasticity by the front axle suspension elasticity to obtain the second compensation coefficient.

[0156] In this case, the second compensation coefficient is positively correlated with the rear axle suspension elasticity and negatively correlated with the front axle suspension elasticity.

[0157] Alternatively, a second compensation coefficient can be determined based on the front axle lateral stiffness, rear axle lateral stiffness, front axle suspension elasticity, and rear axle suspension elasticity, thereby determining a more accurate second compensation coefficient.

[0158] Due to variations in lateral stiffness and suspension elasticity, a vehicle's steering stability can be affected in different ways. For example, if a vehicle's suspension elasticity weakens due to aging or excessive load, or if lateral stiffness becomes unbalanced due to tire wear or road surface variations, the required compensation during steering will be correspondingly higher. Therefore, different states of lateral stiffness and suspension elasticity during steering will lead to different compensation levels. Thus, by comprehensively considering the lateral stiffness of the front axle, rear axle, front axle suspension elasticity, and rear axle suspension elasticity, a more accurate second compensation coefficient can be determined, enabling subsequent steering compensation while maintaining vehicle stability.

[0159] Specifically, the operation of determining the second compensation coefficient based on the front axle lateral stiffness, rear axle lateral stiffness, front axle suspension elasticity, and rear axle suspension elasticity can be as follows: divide the front axle lateral stiffness by the rear axle lateral stiffness to obtain the first reference coefficient; divide the rear axle suspension stiffness by the front axle suspension stiffness to obtain the second reference coefficient; and multiply the first reference coefficient by the second reference coefficient to obtain the second compensation coefficient.

[0160] That is, based on the front axle lateral stiffness, rear axle lateral stiffness, front axle suspension elasticity and rear axle suspension elasticity, the second compensation coefficient is determined by the following formula (1).

[0161] (1)

[0162] It should be noted that the data such as front axle lateral stiffness, rear axle lateral stiffness, front axle suspension elasticity, and rear axle suspension elasticity may be related to the vehicle model. That is, the front axle lateral stiffness, rear axle lateral stiffness, front axle suspension elasticity, and rear axle suspension elasticity may be different for different vehicle models. This application does not limit this.

[0163] (3) Determine the target front wheel angle based on the first compensation coefficient, the second compensation coefficient and the difference in rear wheel angle.

[0164] The rear wheel steering angle difference is the difference between the current rear wheel steering angle of the target vehicle and the target rear wheel steering angle.

[0165] In this case, based on the first compensation coefficient, the second compensation coefficient, and the difference in rear wheel angle, it is equivalent to determining the target front wheel angle by comprehensively considering the ratio between the front wheel angle and the rear wheel angle at the current vehicle speed, as well as the inherent ratio between the front wheel angle and the rear wheel angle. Thus, it is equivalent to determining the compensation coefficient by comprehensively considering multiple angle ratios, thereby determining a more accurate target front wheel angle.

[0166] Specifically, step (3) can be performed by multiplying the first compensation coefficient by the second compensation coefficient to obtain the target compensation coefficient; and by multiplying the rear wheel steering angle difference by the target compensation coefficient to obtain the target front wheel steering angle.

[0167] For example, with a first compensation coefficient of 1.1, a second compensation coefficient of 1.3, and a rear wheel steering angle difference of 20°, the target front wheel steering angle is... °. In other words, to compensate for the 20° abnormal rotation of the rear wheels, the front wheels of the target vehicle need to rotate 28.6° in order to correct the abnormal steering caused by the abnormal rear wheel rotation and ensure that the target vehicle travels in a straight line.

[0168] It is worth noting that, in this embodiment of the application, it can be determined whether the target vehicle is traveling in a straight line before step 301.

[0169] Specifically, the steering wheel angle of the target vehicle is acquired in multiple cycles; if the steering wheel angle in multiple cycles is less than the preset steering wheel angle threshold, it is determined that the target vehicle is traveling in a straight line; otherwise, it is determined that the target vehicle is not traveling in a straight line.

[0170] The preset steering wheel angle threshold can be set in advance, and the preset steering wheel angle threshold can be set according to the steering wheel angle when the front wheels reach an angle. In this embodiment, the preset steering wheel angle threshold can be set to a small value, for example, the preset steering wheel angle threshold can be set to 3°.

[0171] If the steering wheel angle is less than the preset steering wheel angle threshold for multiple cycles, it means that the steering wheel angle is small for multiple cycles and is smaller than the steering wheel angle when the front wheels have an angle. Therefore, it can be determined that the steering wheel of the target vehicle is kept back in center and the front wheels have not had an angle, which means that the target vehicle is traveling in a straight line.

[0172] If a steering wheel angle greater than the preset steering wheel angle threshold exists in multiple cycles, it indicates that the steering wheel angle in this cycle is large and the front wheels have angled, thus confirming that the target vehicle is not maintaining a straight line.

[0173] Furthermore, after determining that the target vehicle is traveling in a straight line, it is also possible to continuously monitor whether the steering wheel of the target vehicle returns to center and whether the rear wheels of the target vehicle exhibit abnormal steering.

[0174] Specifically, first obtain the target vehicle's current steering wheel angle, current rear wheel angle, target rear wheel angle, and current yaw rate; then, based on the target vehicle's current steering wheel angle, current rear wheel angle, target rear wheel angle, and current yaw rate, determine whether the target vehicle's steering wheel remains centered and whether the target vehicle's rear wheels exhibit abnormal steering.

[0175] The current yaw rate refers to the angular velocity of the target vehicle rotating around its vertical axis at the current moment, and is typically used to describe the vehicle's steering behavior. Since the vehicle's yaw rate changes when the rear wheels angle, the current yaw rate can be obtained.

[0176] In this situation, by combining the current steering wheel angle, the current rear wheel angle, the target rear wheel angle, and the current yaw rate, it is possible to accurately determine whether the steering wheel of the target vehicle has returned to center and whether the rear wheels are turning abnormally.

[0177] The operation of determining whether the steering wheel of the target vehicle remains centered and whether the rear wheels of the target vehicle exhibit abnormal steering, based on the current steering wheel angle, current rear wheel angle, target rear wheel angle, and current yaw rate of the target vehicle, can be as follows: subtract the target rear wheel angle from the current rear wheel angle to obtain the rear wheel angle difference; if the current steering wheel angle is less than or equal to a preset steering wheel angle threshold, and the rear wheel angle difference is greater than or equal to a preset difference threshold, and the current yaw rate is greater than or equal to a preset angular velocity threshold, then it is determined that the steering wheel of the target vehicle remains centered and the rear wheels of the target vehicle exhibit abnormal steering; if the current steering wheel angle is less than or equal to a preset steering wheel angle threshold, and the rear wheel angle difference is less than a preset difference threshold, and the current yaw rate is less than a preset angular velocity threshold, then it is determined that the steering wheel of the target vehicle remains centered and the rear wheels of the target vehicle do not exhibit abnormal steering.

[0178] The preset difference threshold can be set in advance, and the preset difference threshold can be set relatively large. For example, the preset difference threshold can be set to 1°.

[0179] The preset angular velocity threshold can be set in advance, and the preset angular velocity threshold can be set relatively large. For example, the preset angular velocity threshold can be set to 1° / s (degrees per second).

[0180] In this situation, if the current steering wheel angle is less than or equal to a preset steering wheel angle threshold, it indicates that the steering wheel is currently centered. Further investigation can then be conducted to determine if the target vehicle's rear wheels are exhibiting abnormal steering. If the rear wheel angle difference is greater than or equal to a preset difference threshold, it indicates a large rear wheel angle difference, meaning the difference between the current rear wheel angle and the target rear wheel angle is significant. Additionally, if the current yaw rate is greater than or equal to a preset yaw rate threshold, it indicates a large yaw rate, suggesting the vehicle has a steering tendency. Therefore, if the current rear wheel angle is large and the vehicle exhibits a steering tendency, it can be concluded that the rear wheels are exhibiting abnormal steering.

[0181] If the rear wheel steering angle difference is less than the preset difference threshold, it indicates that the rear wheel steering angle difference is normal. This means the difference between the current rear wheel steering angle and the target rear wheel steering angle is relatively normal, indicating that the current rear wheel steering angle is normal. Similarly, if the current yaw rate is less than the preset yaw rate threshold, it indicates that the current yaw rate is low, thus indicating that the overall vehicle yaw rate is normal, and there is no steering tendency. In this case, it can be confirmed that there is no abnormal steering of the rear wheels.

[0182] It is worth noting that when the rear wheels of the target vehicle exhibit abnormal steering, step 301 above can determine the angle that the front wheels of the target vehicle need to compensate for. This allows for subsequent correction of the target vehicle's trajectory by compensating for a certain angle. That is, steps 302 and 303 can then be executed.

[0183] Step 302: Determine the target compensation torque based on the target front wheel steering angle.

[0184] In this embodiment, the target vehicle has an electric power steering system. When controlling the front wheel steering, the electric power steering system can control the front wheels to rotate at a certain angle. However, the electric power steering system outputs a certain torque to make the front wheels of the target vehicle rotate at a certain angle. Therefore, in this embodiment, the target compensation torque can also be determined based on the target front wheel steering angle.

[0185] In this case, the target compensation torque is the torque that the electric power steering system needs to compensate for, and it is the torque that needs to be output on top of the current output torque. That is, by outputting the target compensation torque, the front wheels of the target vehicle can be rotated by a target front wheel angle. In this embodiment, the direction of the target compensation torque can be the same as the direction of the current yaw rate.

[0186] Optionally, before determining the target compensation torque, the current vehicle speed, current steering wheel torque, and steering system stiffness of the target vehicle can be obtained first.

[0187] The steering system stiffness of a target vehicle refers to the vehicle's steering system's ability to resist deformation. This steering system stiffness can be calibrated during the production of the target vehicle and stored in the vehicle's memory.

[0188] In this case, step 302 can be performed by determining the target compensation torque based on the target front wheel angle, current vehicle speed, current steering wheel torque, and steering system stiffness.

[0189] Since the angle of front wheel rotation is affected by many factors, such as the current speed of the target vehicle, the torque applied to the steering wheel by the user, and the stiffness of the steering system, the target compensation torque can be calculated based on these parameters.

[0190] Specifically, the operation of determining the target compensation torque based on the target front wheel angle, current vehicle speed, current steering wheel torque, and steering system stiffness can be as follows: determine the target assist coefficient based on the current vehicle speed; multiply the target assist coefficient by the current steering wheel torque to obtain the first assist torque; multiply the target front wheel angle by the steering system stiffness to obtain the second assist torque; and determine the sum of the first assist torque and the second assist torque as the target compensation torque.

[0191] The target assist coefficient refers to the ratio between the torque provided by the electric power steering system and the torque applied by the driver when controlling the front wheels at the current vehicle speed.

[0192] The first assist torque is the torque required by the electric power steering system to overcome the force applied by the user to the steering wheel, and the second assist torque is the torque required by the electric power steering system to overcome the system stiffness when steering.

[0193] Since the electric power steering system must not only overcome the force applied by the user to the steering wheel (to provide assistance to the user) when steering, but also overcome the reverse force brought about by the system stiffness of the steering system, the first assist torque and the second assist torque can be calculated, and the target compensation torque can be determined based on the first assist torque and the second assist torque.

[0194] In this case, the sum of the first assist torque and the second assist torque is determined as the target compensation torque. This target compensation torque can counteract the force applied by the user on the steering wheel and the reverse force brought about by the stiffness of the steering system, thereby obtaining a more accurate target compensation torque, which allows for more precise adjustment of the front wheel angle in the future.

[0195] The operation of determining the target assist coefficient based on the current vehicle speed can be as follows: if the current vehicle speed is less than or equal to the target vehicle speed threshold, the target assist coefficient is determined as the first coefficient; if the current vehicle speed is greater than the target vehicle speed threshold, the target assist coefficient is determined as the second coefficient.

[0196] The first coefficient and the second coefficient can be preset, and the first coefficient is the target assist coefficient when the target vehicle is traveling at low speed, and the second coefficient is the target assist coefficient when the target vehicle is traveling at high speed.

[0197] As one implementation method, the target assist coefficient can also be determined according to the following formula (2).

[0198] (2)

[0199] Where k is the target assist coefficient. As the first coefficient, The second coefficient is denoted by v, where v is the current vehicle speed. The target vehicle speed threshold. The parameters for a smooth transition can be set in advance.

[0200] For example, the first coefficient is 0.5, the second coefficient is 0.2, the smooth transition parameter is 1, the current vehicle speed is 30, and the target vehicle speed threshold is 50. Then, the target assist coefficient is determined by the above formula (2) as shown below.

[0201]

[0202] Step 303: Control the front wheel motor of the target vehicle to output the target compensation torque, so as to keep the target vehicle in a straight-line driving state by adjusting the front wheel angle of the target vehicle.

[0203] In this situation, by controlling the output of the target compensation torque of the front wheel motor of the target vehicle, the front wheel is controlled to rotate at a certain angle, so that the front wheel can compensate for the trajectory deviation caused by the abnormal steering of the rear wheel, thereby keeping the target vehicle in a straight driving state and improving driving safety.

[0204] In this embodiment, the electric power steering system of the target vehicle can also control the power steering motor to output the target compensation torque. In this case, the electric power steering system sends a signal to the power steering motor to output the target compensation torque, thereby enabling subsequent control of the power steering motor of the target vehicle to output the target compensation torque.

[0205] It should be understood that the power steering motor is the motor controlled by the electric power steering system of the target vehicle.

[0206] Optionally, the power assist motor of the target vehicle can be controlled to output a target compensation torque based on the current assist torque.

[0207] Specifically, the target compensation torque is added to the current assist torque to obtain the target assist torque; the assist motor of the target vehicle is controlled to output the target assist torque in order to adjust the front wheel angle of the target vehicle.

[0208] The current assist torque is the assist torque output by the power steering motor of the target vehicle when it is determined that the rear wheels are turning abnormally. It should be understood that, in the embodiments of this application, if the current steering wheel angle is 0, the current front wheel angle should also be 0, and therefore the current assist torque can be 0.

[0209] When the current assist torque is 0, the target assist torque is also the target compensation torque.

[0210] The operation of adding the target compensation torque to the current assist torque to obtain the target assist torque can be as follows: obtain the first weight corresponding to the target compensation torque; obtain the second weight corresponding to the current assist torque; and perform a weighted summation of the target compensation torque and the current assist torque based on the first weight and the second weight to obtain the target assist torque.

[0211] The first and second weights can be preset by technical personnel.

[0212] In this case, by weighting and summing the target compensation torque and the current assist torque, the front wheels can be turned slowly to gradually bring the front wheel angle to the target front wheel angle. This makes the rotation of the front wheels of the target vehicle smoother and more fluid, rather than directly outputting the target compensation torque to make the front wheels suddenly turn to the target front wheel angle. This can improve the user experience.

[0213] It is worth noting that, in the embodiments of this application, the target compensation torque can be determined in multiple iterations, and in the process of multiple iterations, the target compensation torque determined in each round is added to the current assist torque to obtain the target assist torque.

[0214] The above multi-round iterative process is explained using a 3-round iterative process.

[0215] In the first iteration, the target front wheel angle is determined based on the current rear wheel angle, the target rear wheel angle (the angle at which the rear wheel returned to positive in the previous cycle), and vehicle parameters. The target compensation torque is then determined based on the target front wheel angle. The target compensation torque is then weighted and summed with the current assist torque to obtain the target assist torque for the first iteration. The assist motor is then controlled to output the target assist torque for the first iteration.

[0216] In the second iteration, the target assist torque is the current assist torque of the second iteration. The target front wheel angle is subtracted from the current front wheel angle to obtain the front wheel rotation angle during the second iteration. Based on the front wheel rotation angle during the second iteration, the target compensation torque is determined. Then, the target compensation torque determined in the second iteration is weighted and summed with the current assist torque to obtain the target assist torque determined in the second iteration. Subsequently, the assist motor is controlled to output the target assist torque of the second iteration.

[0217] In the third iteration, the target assist torque is the current assist torque of the third iteration. The front wheel rotation angle at the second iteration is subtracted from the current front wheel rotation angle to obtain the front wheel rotation angle at the third iteration. Based on this rotation angle, the target compensation torque is determined. Then, the target compensation torque determined in the third iteration is weighted and summed with the current assist torque to obtain the target assist torque determined in the third iteration. Subsequently, the assist motor is controlled to output the target assist torque of the third iteration.

[0218] In this scenario, the first and second weights can adaptively change during multiple iterations. The trend is that the first weight increases over multiple iterations, while the second weight decreases. This results in a greater output of the target compensation torque during the iterations, gradually increasing the front wheel steering angle to correct trajectory deviation.

[0219] In addition, during multiple rounds of iterative updates, the current rear wheel angle can be detected in real time. In this case, the compensation torque can be iteratively updated based on the real-time detected current rear wheel angle.

[0220] Specifically, during multiple iterations, the current rear wheel angle is obtained in real time. The difference between the current rear wheel angle and the target rear wheel angle is updated based on the real-time detected current rear wheel angle. The target front wheel angle is determined based on the updated rear wheel angle difference and the vehicle parameters of the target vehicle. Then, the target compensation torque is determined based on the determined target front wheel angle. This enables the target compensation torque to be continuously updated based on the real-time detected rear wheel angle during multiple iterations, and the target compensation torque output by the front wheel motor is continuously adjusted during multiple iterations.

[0221] For ease of understanding, the process of determining the target assist torque in the embodiments of this application will now be described with reference to Figure 4. For example, Figure 4 is a flowchart of determining the target assist torque provided in an embodiment of this application.

[0222] As shown in Figure 4, the difference between the current rear wheel angle of the target vehicle and the rear wheel angle of the previous cycle (target rear wheel angle) is first calculated (rear wheel angle difference). Then, the rear wheel angle difference is multiplied by the target compensation coefficient to obtain the target front wheel angle. Next, torque is calculated on the target front wheel angle to determine the target compensation torque required to rotate the front wheels to the target front wheel angle. Finally, the target compensation torque and the current assist torque are weighted and summed (the target compensation torque is multiplied by the first weight 'a' and the current assist torque is multiplied by the second weight 'b') to obtain the compensated assist torque, which is the target assist torque.

[0223] It is worth noting that in this embodiment, after the target vehicle is powered on, the vehicle controller continuously monitors the steering wheel angle, rear wheel angle, and yaw rate. If the current steering wheel angle is less than or equal to a preset steering wheel angle threshold, and the rear wheel angle difference is greater than or equal to a preset difference threshold, and the current yaw rate is greater than or equal to a preset yaw rate threshold, it is determined that the target vehicle has experienced abnormal rear wheel steering while maintaining straight-line driving. At this time, the vehicle controller can send an unexpected steering compensation function activation signal to the EPS system. Upon receiving the signal, the EPS system activates the unexpected steering compensation function and sends a feedback signal to the vehicle controller indicating that the function is activated. The EPS system can then execute steps 301-303 to calculate a target compensation torque, allowing the power steering motor to output the target compensation torque based on the current output torque. This achieves the correction of trajectory deviation caused by abnormal rear wheel steering by rotating the front wheels at a certain angle.

[0224] In addition, during the aforementioned process of front wheel torque compensation, the vehicle controller continuously monitors the steering wheel angle and rear wheel angle. If the current steering wheel angle is less than or equal to a preset steering wheel angle threshold, and the rear wheel angle difference is less than a preset difference threshold and the current yaw rate is less than a preset angular velocity threshold, it is determined that the rear wheels are working normally. In this case, an unexpected steering compensation function exit command signal can be sent to the EPS system. After receiving the command signal, the EPS system will turn off the unexpected steering compensation function and control the motor output according to the normal power assist torque.

[0225] For ease of understanding, the vehicle control method provided in this application embodiment will now be described by way of example with reference to FIG5. For example, FIG5 is a flowchart of another vehicle control method provided in this application embodiment. Referring to FIG5, it is assumed that the preset steering wheel angle threshold is 3°, the preset angular velocity threshold is 1° / s, and the preset difference threshold is 1°. FIG5 includes steps 501-507.

[0226] Step 501: Obtain the current steering wheel angle, the current rear wheel angle, and the current yaw rate, and calculate the difference in rear wheel angle.

[0227] Step 502: Determine if the current steering wheel angle is less than 3°. If the current steering wheel angle is less than 3°, proceed to step 503 below.

[0228] Step 503: Determine whether the rear wheel steering angle difference is greater than or equal to 1° and whether the current yaw rate is greater than or equal to 1° / s. If the rear wheel steering angle difference is greater than or equal to 1° and the current yaw rate is greater than or equal to 1° / s, proceed to step 504 below; otherwise, proceed to step 507.

[0229] Step 504: Determine the target front wheel steering angle based on the rear wheel steering angle difference and the vehicle parameters of the target vehicle.

[0230] Step 505: Determine the target compensation torque based on the target front wheel steering angle.

[0231] Step 506: Control the front wheel motor to output the target compensation torque and execute step 503 above.

[0232] Step 507: Confirm that there is no abnormality in the rear wheels and do not activate the unexpected steering compensation function.

[0233] In this embodiment, when the steering wheel of the target vehicle remains centered and the rear wheels of the target vehicle exhibit abnormal steering, the vehicle controller first determines the target front wheel angle based on the difference between the current rear wheel angle and the target rear wheel angle, as well as vehicle parameters. This means determining the angle at which the front wheels of the target vehicle should rotate to compensate for the abnormal steering of the rear wheels. Then, based on the target front wheel angle, the target compensation torque is determined, which is the torque that the front wheels should compensate for. Finally, the front wheel motors of the target vehicle are controlled to output the target compensation torque to maintain the target vehicle in a straight-line driving state by adjusting the front wheel angle. This application, when the rear wheels of the target vehicle exhibit abnormal steering while the vehicle is driving straight, controls the front wheels to rotate by a certain angle by outputting the target compensation torque from the front wheel motors. This compensates for the trajectory deviation caused by the abnormal steering of the rear wheels, thereby maintaining the target vehicle in a straight-line driving state and improving driving safety.

[0234] Figure 6 is a schematic diagram of a vehicle control device provided in an embodiment of this application. This vehicle control device can be implemented as part or all of a vehicle by software, hardware, or a combination of both, and the vehicle can be the vehicle shown in Figure 7 below. Referring to Figure 6, the device includes: a first determining module 601, a second determining module 602, and a torque output module 603.

[0235] The first determining module 601 is used to determine the target front wheel angle based on the difference between the current rear wheel angle and the target rear wheel angle, and vehicle parameters, when the steering wheel of the target vehicle is kept in the center and the rear wheel of the target vehicle exhibits abnormal steering. The target rear wheel angle is the angle of the rear wheel of the target vehicle when it is in the center state, and the target front wheel angle is the angle that the front wheel of the target vehicle should rotate to compensate for the abnormal steering of the rear wheel. The vehicle parameters include dynamic vehicle parameters and static vehicle parameters.

[0236] The second determining module 602 is used to determine the target compensation torque based on the target front wheel steering angle;

[0237] The torque output module 603 is used to control the front wheel motor of the target vehicle to output the target compensation torque, so as to keep the target vehicle in a straight-line driving state by adjusting the front wheel angle of the target vehicle.

[0238] Optionally, the device further includes:

[0239] The first acquisition module is used to acquire the target vehicle's current steering wheel angle, current rear wheel angle, target rear wheel angle, and current yaw rate;

[0240] The third determining module is used to determine whether the steering wheel of the target vehicle remains centered and whether the rear wheels of the target vehicle exhibit abnormal steering based on the current steering wheel angle, the current rear wheel angle, the target rear wheel angle, and the current yaw rate.

[0241] Optionally, the third determining module is used for:

[0242] Subtract the target rear wheel angle from the current rear wheel angle to obtain the rear wheel angle difference;

[0243] If the current steering wheel angle is less than or equal to the preset steering wheel angle threshold, the rear wheel angle difference is greater than or equal to the preset difference threshold, and the current yaw rate is greater than or equal to the preset yaw rate threshold, then the steering wheel of the target vehicle is determined to remain centered and the rear wheels of the target vehicle are found to be abnormally turning.

[0244] If the current steering wheel angle is less than or equal to the preset steering wheel angle threshold, the difference in rear wheel angle is less than the preset difference threshold, and the current yaw rate is less than the preset angular rate threshold, then the steering wheel of the target vehicle remains centered and the rear wheels of the target vehicle do not exhibit abnormal steering.

[0245] Optionally, the static vehicle parameters include the axle attributes of the target vehicle, and the dynamic vehicle parameters include the current driving parameters of the target vehicle. The first determining module 601 is used for:

[0246] The target front wheel angle is determined based on the difference between the current rear wheel angle and the target rear wheel angle of the target vehicle, the axle attributes, and the current driving parameters.

[0247] Optionally, the axle attributes include front axle lateral stiffness and rear axle lateral stiffness, and the current driving parameters include the current vehicle speed. The first determining module 601 is used for:

[0248] Based on the current vehicle speed, a first compensation coefficient is determined. The first compensation coefficient is used to represent the ratio between the front wheel angle and the rear wheel angle of the target vehicle at the current vehicle speed.

[0249] Based on the front axle lateral stiffness and the rear axle lateral stiffness, a second compensation coefficient is determined. The second compensation coefficient is used to represent the inherent angle ratio between the front wheel angle and the rear wheel angle of the target vehicle.

[0250] Based on the first compensation coefficient, the second compensation coefficient, and the rear wheel angle difference, the target front wheel angle is determined, and the rear wheel angle difference is the difference between the current rear wheel angle of the target vehicle and the target rear wheel angle.

[0251] Optionally, the axle attributes also include front axle suspension elasticity and rear axle suspension elasticity, and the first determining module 601 is further used for:

[0252] The second compensation coefficient is determined based on the front axle lateral stiffness, rear axle lateral stiffness, front axle suspension elasticity, and rear axle suspension elasticity.

[0253] Optionally, the first determining module 601 is further specifically used for:

[0254] Divide the front axle side stiffness by the rear axle side stiffness to obtain the first reference coefficient.

[0255] Divide the rear axle suspension stiffness by the front axle suspension stiffness to obtain the second reference coefficient;

[0256] Multiply the first reference coefficient by the second reference coefficient to obtain the second compensation coefficient.

[0257] Optionally, the first determining module 601 is used for:

[0258] Multiply the first compensation coefficient by the second compensation coefficient to obtain the target compensation coefficient;

[0259] Multiply the difference in rear wheel steering angle by the target compensation coefficient to obtain the target front wheel steering angle.

[0260] Optionally, the device further includes:

[0261] The second acquisition module is used to acquire the target vehicle's current speed, current steering wheel torque, and steering system stiffness, which refers to the target vehicle's steering system's ability to resist deformation.

[0262] Optionally, the second determining module 602 is used for:

[0263] The target compensation torque is determined based on the target front wheel angle, current vehicle speed, current steering wheel torque, and steering system stiffness.

[0264] Optionally, the second determining module 602 is used for:

[0265] Based on the current vehicle speed, the target assist coefficient is determined. The target assist coefficient refers to the ratio between the torque provided by the steering system when controlling the front wheel steering at the current vehicle speed and the torque applied by the driver.

[0266] Multiply the target assist coefficient by the current steering wheel torque to obtain the first assist torque;

[0267] Multiply the target front wheel steering angle by the steering system stiffness to obtain the second assist torque;

[0268] The sum of the first assist torque and the second assist torque is determined as the target compensation torque.

[0269] Optionally, the second determining module 602 is specifically used for:

[0270] When the current vehicle speed is less than or equal to the target vehicle speed threshold, the target assist coefficient is determined as the first coefficient. The first coefficient is the target assist coefficient when the target vehicle is traveling at low speed.

[0271] When the current vehicle speed is greater than the target vehicle speed threshold, the target assist coefficient is determined as the second coefficient, which is the target assist coefficient when the target vehicle is traveling at high speed.

[0272] Optionally, the torque output module 603 is also used for:

[0273] The target assist torque is obtained by adding the target compensation torque to the current assist torque of the assist motor of the target vehicle. The assist motor is the motor controlled by the electric power steering system of the target vehicle.

[0274] Control the power assist motor of the target vehicle to output the target assist torque in order to adjust the front wheel angle of the target vehicle.

[0275] Optionally, the torque output module 603 is also used for:

[0276] Obtain the first weight corresponding to the target compensation torque;

[0277] Obtain the second weight corresponding to the current assist torque;

[0278] Based on the first and second weights, the target compensation torque and the current assist torque are weighted and summed to obtain the target assist torque.

[0279] In this embodiment, when the steering wheel of the target vehicle remains centered and the rear wheels of the target vehicle exhibit abnormal steering, the target front wheel angle is first determined based on the difference between the current rear wheel steering angle and the target rear wheel steering angle, along with vehicle parameters. This determines the angle at which the front wheels of the target vehicle should rotate to compensate for the abnormal steering of the rear wheels. Then, based on the target front wheel steering angle, the target compensation torque is determined, i.e., the torque that the front wheels should compensate for. Finally, the front wheel motor of the target vehicle is controlled to output the target compensation torque to maintain the target vehicle in a straight-line driving state by adjusting the front wheel angle. This application, when the rear wheels of the target vehicle exhibit abnormal steering while the vehicle is driving straight, controls the front wheels to rotate by a certain angle by outputting the target compensation torque from the front wheel motor. This compensates for the trajectory deviation caused by the abnormal steering of the rear wheels, thereby maintaining the target vehicle in a straight-line driving state and improving driving safety.

[0280] It should be noted that the vehicle control device provided in the above embodiments, when controlling the vehicle when the rear wheels of the vehicle steer abnormally, is only illustrated by the division of the above functional modules. In actual applications, the above 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.

[0281] The functional units and modules in the above embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of the embodiments of this application.

[0282] The vehicle control device and vehicle control method embodiments provided in the above embodiments belong to the same concept. The specific working process and technical effects of the units and modules in the above embodiments can be found in the method embodiment section, and will not be repeated here.

[0283] Figure 7 is a structural schematic diagram of a vehicle provided in an embodiment of this application.

[0284] For example, as shown in FIG7, the vehicle 700 includes a memory 71 and a processor 70, wherein the memory 71 stores executable program code 72, and the processor 70 is used to call and execute the executable program code 72 to perform the above-described vehicle control method.

[0285] This embodiment can divide the vehicle into functional modules according to the above method example. For example, each function can be assigned to a separate module, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware. It should be noted that the module division in this embodiment is illustrative and only represents one logical functional division. In actual implementation, there may be other division methods.

[0286] When each functional module is divided according to its corresponding function, the vehicle may include: a first determining module, a second determining module, and a torque output module. It should be noted that all relevant content regarding the steps involved in the above method embodiments can be referenced from the functional descriptions of the corresponding functional modules, and will not be repeated here.

[0287] The vehicle provided in this embodiment is used to execute the vehicle control method described above, and therefore can achieve the same effect as the above implementation method.

[0288] When using integrated units, the vehicle may include a processing module and a storage module. The processing module is used to control and manage the vehicle's actions. The storage module is used to support the vehicle in executing corresponding program code and data.

[0289] The processing module may be a processor or a controller, which can implement or execute various exemplary logic blocks, modules, and circuits shown in conjunction with the disclosure of this application. The processor may also be a combination of functions that implement computing capabilities, such as a combination of one or more microprocessors, a combination of digital signal processing (DSP) and a microprocessor, etc., and the storage module may be a memory.

[0290] This embodiment also provides a computer-readable storage medium storing computer program code. When the computer program code is run on a computer, the computer executes the aforementioned method steps to implement the vehicle control method described in the above embodiment.

[0291] This embodiment also provides a computer program product that, when run on a computer, causes the computer to perform the aforementioned steps to implement the vehicle control method described in the above embodiment.

[0292] In this embodiment, the vehicle, computer-readable storage medium, computer program product, or chip are all used to execute the method described above. Therefore, the beneficial effects that can be achieved can be referred to the beneficial effects of the method described above, and will not be repeated here.

[0293] Through the above description of the embodiments, those skilled in the art will understand that, for the sake of convenience and brevity, only the division of the above functional modules is used as an example. In actual applications, the above 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.

[0294] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are illustrative; for instance, the division of modules or units is merely a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0295] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A vehicle control method in which, The method includes: When the steering wheel of the target vehicle remains centered and the rear wheels of the target vehicle exhibit abnormal steering, the target front wheel steering angle is determined based on the difference between the current rear wheel steering angle and the target rear wheel steering angle, as well as vehicle parameters. The target rear wheel steering angle is the angle of the rear wheels of the target vehicle when they are centered, and the target front wheel steering angle is the angle that the front wheels of the target vehicle should rotate to compensate for the abnormal steering of the rear wheels. The vehicle parameters include dynamic vehicle parameters and static vehicle parameters. Based on the target front wheel steering angle, determine the target compensation torque; The target vehicle's front wheel motor is controlled to output the target compensation torque, so as to keep the target vehicle in a straight-line driving state by adjusting the front wheel angle.

2. The method of claim 1, wherein, Before determining the target front wheel steering angle based on the difference between the current rear wheel steering angle and the target rear wheel steering angle, and vehicle parameters, when the steering wheel of the target vehicle is kept centered and the rear wheels of the target vehicle exhibit abnormal steering, the method further includes: The current steering wheel angle, the current rear wheel angle, the target rear wheel angle, and the current yaw rate of the target vehicle are obtained. Based on the current steering wheel angle, the current rear wheel angle, the target rear wheel angle, and the current yaw rate, determine whether the steering wheel of the target vehicle remains centered and whether the rear wheels of the target vehicle exhibit abnormal steering.

3. The method of claim 2, wherein, The determination of whether the steering wheel of the target vehicle remains centered and whether the rear wheels of the target vehicle exhibit abnormal steering, based on the current steering wheel angle, the current rear wheel angle, the target rear wheel angle, and the current yaw rate, includes: Subtract the target rear wheel angle from the current rear wheel angle to obtain the rear wheel angle difference; If the current steering wheel angle is less than or equal to a preset steering wheel angle threshold, the rear wheel angle difference is greater than or equal to a preset difference threshold, and the current yaw rate is greater than or equal to a preset angular rate threshold, then it is determined that the steering wheel of the target vehicle remains centered and the rear wheels of the target vehicle exhibit abnormal steering. If the current steering wheel angle is less than or equal to the preset steering wheel angle threshold, the rear wheel angle difference is less than the preset difference threshold, and the current yaw rate is less than the preset angular rate threshold, then it is determined that the steering wheel of the target vehicle remains centered and the rear wheels of the target vehicle do not exhibit abnormal steering.

4. The method of claim 1, wherein, The static vehicle parameters include the axle attributes of the target vehicle, and the dynamic vehicle parameters include the current driving parameters of the target vehicle. Determining the target front wheel steering angle based on the difference between the current rear wheel steering angle and the target rear wheel steering angle, along with the vehicle parameters, includes: The target front wheel angle is determined based on the difference between the current rear wheel angle and the target rear wheel angle of the target vehicle, the axle attributes, and the current driving parameters.

5. The method of claim 4, wherein, The axle attributes include front axle lateral stiffness and rear axle lateral stiffness; the current driving parameters include current vehicle speed; and determining the target front wheel steering angle based on the difference between the current rear wheel steering angle and the target rear wheel steering angle, the axle attributes, and the current driving parameters includes: Based on the current vehicle speed, a first compensation coefficient is determined. The first compensation coefficient is used to represent the ratio between the front wheel angle and the rear wheel angle of the target vehicle at the current vehicle speed. Based on the front axle lateral stiffness and the rear axle lateral stiffness, a second compensation coefficient is determined. The second compensation coefficient is used to represent the inherent angle ratio between the front wheel angle and the rear wheel angle of the target vehicle. Based on the first compensation coefficient, the second compensation coefficient, and the rear wheel angle difference, the target front wheel angle is determined, and the rear wheel angle difference is the difference between the current rear wheel angle of the target vehicle and the target rear wheel angle.

6. The method of claim 5, wherein, The axle attributes also include front axle suspension elasticity and rear axle suspension elasticity. The determination of the second compensation coefficient based on the front axle lateral stiffness and the rear axle lateral stiffness includes: The second compensation coefficient is determined based on the front axle lateral stiffness, the rear axle lateral stiffness, the front axle suspension elasticity, and the rear axle suspension elasticity.

7. The method of claim 6, wherein, The determination of the second compensation coefficient based on the front axle lateral stiffness, the rear axle lateral stiffness, the front axle suspension elasticity, and the rear axle suspension elasticity includes: Divide the front axle lateral stiffness by the rear axle lateral stiffness to obtain the first reference coefficient; Divide the rear axle suspension stiffness by the front axle suspension stiffness to obtain the second reference coefficient; The second compensation coefficient is obtained by multiplying the first reference coefficient by the second reference coefficient.

8. The method of claim 5, wherein, Determining the target front wheel steering angle based on the first compensation coefficient, the second compensation coefficient, and the rear wheel steering angle difference includes: Multiply the first compensation coefficient by the second compensation coefficient to obtain the target compensation coefficient; The target front wheel steering angle is obtained by multiplying the difference in rear wheel steering angle by the target compensation coefficient.

9. The method of claim 1, wherein, Before determining the target compensation torque based on the target front wheel steering angle, the process also includes: The current vehicle speed, current steering wheel torque, and steering system stiffness of the target vehicle are obtained. Steering system stiffness refers to the ability of the target vehicle's steering system to resist deformation. Determining the target compensation torque based on the target front wheel steering angle includes: The target compensation torque is determined based on the target front wheel angle, the current vehicle speed, the current steering wheel torque, and the steering system stiffness.

10. The method of claim 9, wherein, The determination of the target compensation torque based on the target front wheel steering angle, the current vehicle speed, the current steering wheel torque, and the steering system stiffness includes: Based on the current vehicle speed, a target assist coefficient is determined. The target assist coefficient refers to the ratio between the torque provided by the steering system when controlling the front wheel steering at the current vehicle speed and the torque applied by the driver. Multiply the target assist coefficient by the current steering wheel torque to obtain the first assist torque; Multiplying the target front wheel steering angle by the steering system stiffness yields the second assist torque; The sum of the first assist torque and the second assist torque is determined as the target compensation torque.

11. The method of claim 10, wherein, Determining the target assist coefficient based on the current vehicle speed includes: When the current vehicle speed is less than or equal to the target vehicle speed threshold, the target assist coefficient is determined to be the first coefficient, and the first coefficient is the target assist coefficient when the target vehicle is traveling at a low speed. If the current vehicle speed is greater than the target vehicle speed threshold, the target assist coefficient is determined as the second coefficient, which is the target assist coefficient when the target vehicle is traveling at high speed.

12. The method of claim 1, wherein, The method further includes: The target assist torque is obtained by adding the target compensation torque to the current assist torque of the power assist motor of the target vehicle, wherein the power assist motor is the motor controlled by the electric power steering system of the target vehicle. The power assist motor of the target vehicle is controlled to output the target assist torque in order to adjust the front wheel angle of the target vehicle.

13. The method of claim 12, wherein, The step of adding the target compensation torque to the current assist torque of the target vehicle's power steering motor to obtain the target assist torque includes: Obtain the first weight corresponding to the target compensation torque; Obtain the second weight corresponding to the current assist torque; Based on the first weight and the second weight, the target compensation torque and the current assist torque are weighted and summed to obtain the target assist torque.

14. A vehicle, wherein, The vehicles include: Memory, used to store executable program code; A processor for calling and running the executable program code from the memory, causing the vehicle to perform the method as described in any one of claims 1 to 13.

15. A computer readable storage medium, wherein, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the method as described in any one of claims 1 to 13.

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