A steering control method of an electric vehicle and an electric vehicle

Abstract

The application discloses a steering control method of an electric vehicle and the electric vehicle. The method comprises the following steps: in response to triggering of a spot steering instruction, determining whether the vehicle is in a preset vehicle working condition, and if yes, controlling a steering controller to lock a steering wheel; acquiring a first tangential velocity of any front wheel of the vehicle and a second tangential velocity of a rear wheel arranged in a diagonal line with the front wheel, and determining a compensation velocity of the rear wheel according to the first tangential velocity and the second tangential velocity, and determining a compensation torque according to the compensation velocity; acquiring an initial torque requested by a rear wheel driving motor for driving the rear wheel to rotate, and determining a driving torque of the rear wheel driving motor according to the initial torque and the compensation torque. The tangential velocities of the front wheel and the rear wheel arranged in the diagonal line are respectively acquired to determine the compensation torque, and the driving torque of the rear wheel driving motor is obtained according to the initial torque and the compensation torque, so that the vehicle mass center is prevented from being obviously offset due to different road adhesion coefficients, and the stability and safety of spot steering are improved.

Description

Technical Field

[0001] This application relates to the field of electric vehicle in-situ steering technology, specifically to a steering control method for an electric vehicle and an electric vehicle. Background Technology

[0002] With the rapid development of vehicle electrification and intelligence, various types of electric vehicles have emerged and penetrated into all industries and fields related to national economy and people's livelihood. From electric buses to electric passenger cars, from electric logistics vehicles to electric forklifts in factory workshops, these vehicles all have a complete steering mechanism. By operating the steering wheel, the steering wheels are driven to deflect in order to achieve vehicle turning and U-turn.

[0003] Existing technologies employ four drive motors, each driving one of the four wheels with the same torque, to achieve vehicle steering in place. However, when road conditions are complex, resulting in different coefficients of friction for each wheel, steering in place with the same torque can easily cause the vehicle's center of gravity to shift. When the shift is large, the stability and safety of the vehicle during in-place steering cannot be guaranteed. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a steering control method for an electric vehicle and an electric vehicle in general. By compensating for torque and determining the initial torque requested by the rear-wheel drive motor, the driving torque of the rear-wheel drive motor is determined, thereby ensuring the stability and safety of the vehicle when turning in place on any surface with different adhesion combinations.

[0005] To achieve the above objectives, the present invention provides a steering control method for an electric vehicle, the vehicle comprising two front wheels and two rear wheels, each of which is driven by a different drive motor. The method includes the following steps:

[0006] In response to the triggering of the stationary turning command, it is determined whether the vehicle is in a preset vehicle operating condition. If so, the steering controller is controlled to lock the steering wheel.

[0007] The first tangential velocity of any front wheel of the vehicle and the second tangential velocity of the rear wheel diagonally opposite to the front wheel are obtained, and the compensation speed of the rear wheel is determined based on the first tangential velocity and the second tangential velocity, and the compensation torque is determined based on the compensation speed.

[0008] Obtain the initial torque requested by the rear-wheel drive motor to drive the rear wheels, and determine the drive torque of the rear-wheel drive motor based on the initial torque and the compensation torque.

[0009] Optionally, determining whether the vehicle is in a preset vehicle operating condition, and if so, controlling the steering controller to lock the steering wheel, includes:

[0010] Determine whether the vehicle's brake pedal is depressed and whether the vehicle's current speed is zero. If the brake pedal is depressed and the current speed is zero, control the vehicle controller to send a steering wheel lock request to the steering controller.

[0011] In response to the triggering of the steering wheel lock request, the steering controller is controlled to adjust the steering wheel to the zero position, and the steering wheel is locked when the steering wheel angle is less than or equal to a preset angle threshold.

[0012] Optionally, after locking the steering wheel when the steering wheel angle is less than or equal to a preset angle threshold, the following steps are included:

[0013] In response to the triggering of the stationary turn-out command, it is determined whether the vehicle's brake pedal is depressed and whether the vehicle's current speed is zero. If the brake pedal is depressed and the current speed is zero, the vehicle controller is controlled to send a steering wheel unlock request to the steering controller.

[0014] In response to the triggering of the steering wheel unlock request, the steering controller is controlled to unlock the steering wheel.

[0015] Optionally, determining the compensation speed of the rear wheel based on the first tangential speed and the second tangential speed, and determining the compensation torque based on the compensation speed, includes:

[0016] The difference between the first tangential velocity and the second tangential velocity is determined as the compensation velocity, and the vehicle controller is controlled to determine the compensation torque based on the compensation velocity.

[0017] Optionally, obtaining the first tangential velocity of any front wheel of the vehicle and the second tangential velocity of the rear wheel diagonally opposite to the front wheel includes:

[0018] The first lateral acceleration and the first longitudinal acceleration of the front wheel are obtained, and the first tangential acceleration is determined based on the first lateral acceleration and the first longitudinal acceleration.

[0019] The second lateral acceleration and the second longitudinal acceleration of the rear wheel are obtained, and the second tangential acceleration is determined based on the second lateral acceleration and the second longitudinal acceleration.

[0020] The current speed of the vehicle is obtained, the first tangential speed is determined based on the current speed and the first tangential acceleration, and the second tangential speed is determined based on the current speed and the second tangential acceleration.

[0021] Optionally, obtaining the current speed of the vehicle includes:

[0022] The accelerator pedal opening is calculated based on the operating voltage output by the accelerator pedal, and the current speed is determined based on the accelerator pedal opening.

[0023] Optionally, obtaining the initial torque requested by the rear-wheel drive motor for driving the rear wheels includes:

[0024] The total requested torque of all the drive motors is determined based on the accelerator pedal opening. The maximum drivable torque and the maximum permissible drivable torque of the vehicle are obtained. The minimum value among the total requested torque, the maximum drivable torque and the maximum permissible drivable torque is determined as the total torque to be allocated.

[0025] The initial torque is determined by dividing the total torque to be allocated by the total number of wheels of the vehicle.

[0026] Optionally, determining the drive torque of the rear-wheel drive motor based on the initial torque and the compensated torque includes:

[0027] The sum of the initial torque and the compensation torque is determined as the driving torque.

[0028] Optionally, obtaining the initial torque requested by the rear-wheel drive motor for driving the rear wheels to rotate further includes:

[0029] Obtain the road surface adhesion coefficient of the road where the vehicle is located, and determine the initial torque based on the road surface adhesion coefficient.

[0030] The present invention also provides an electric vehicle, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, it implements the steps of the steering control method for the electric vehicle as described above.

[0031] This invention determines the compensation torque by acquiring the tangential velocities of the diagonally arranged front and rear wheels during a vehicle's stationary turn. The driving torque of the rear-wheel drive motor is then determined based on the initial torque requested by the rear-wheel drive motor and the compensation torque. The front wheels rotate with the initial torque, while the rear wheels rotate with the driving torque. This ensures that the tangential velocities of the front and rear wheels are close during the stationary turn, preventing significant shifts in the vehicle's center of gravity during stationary turns on various surface surfaces and improving the stability and safety of the vehicle's stationary turn. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the structure of an electric vehicle provided in one embodiment of this application;

[0034] Figure 2 A schematic flowchart of a steering control method for an electric vehicle provided in an embodiment of this application;

[0035] Figure 3 A schematic diagram illustrating the tangential velocity of the wheels of an electric vehicle when it turns in place, according to an embodiment of this application.

[0036] Figure 4 A schematic diagram showing the relationship between the stationary turning angular velocity of an electric vehicle and the accelerator pedal opening, provided in an embodiment of this application;

[0037] Figure 5 This is a schematic diagram illustrating how an electric vehicle controller sends a torque request to a drive motor, according to an embodiment of this application. Detailed Implementation

[0038] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. Based on the description of the present invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of the present invention.

[0039] The following specific embodiments illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification.

[0040] In the description of this invention, unless otherwise expressly specified and limited, the terms "first," "second," "third," etc., are used merely to distinguish elements with similar properties, and not to indicate or imply relative importance or a specific order.

[0041] Furthermore, the terms “including,” “comprising,” or any other variations thereof are intended to cover non-exclusive inclusion, which includes not only the elements listed but also other elements not expressly listed.

[0042] Please refer to Figure 1 , Figure 1A schematic diagram of an electric vehicle is shown. The vehicle includes front and rear wheels. The front wheels include a left front wheel and a right front wheel, and the rear wheels include a left rear wheel and a right rear wheel. Each of the four wheels is driven by a different drive motor. The vehicle's power battery provides the driving energy. The drive motor system is responsible for converting electrical energy into mechanical energy to drive the vehicle. The vehicle control unit (VCU) is responsible for the main control of the vehicle's stationary steering. Based on the driver's stationary steering command and steering speed request, it can issue steering wheel locking commands, calculate the four drive motor modes, and drive torque. MCU_LF is the left front wheel motor controller, MCU_RF is the right front wheel motor controller, MCU_LR is the left rear wheel drive motor controller, and MCU_RR is the right rear wheel motor controller. Each motor controller is responsible for executing the motor operating mode and motor torque requests sent by the VCU. It can be understood that when the electric vehicle is turning in place, the left front wheel and left rear wheel rotate along a first deflection direction, and the right front wheel and right rear wheel rotate along a second deflection direction opposite to the first deflection direction. For example, when a vehicle turns clockwise in place, the two wheels on the left side of the vehicle apply forward driving force and rotate forward, while the two wheels on the right side of the vehicle apply backward driving force and rotate backward. The first deflection direction is forward, and the second deflection direction is backward, and vice versa.

[0043] Please refer to Figure 2 , Figure 2 A flowchart illustrating a steering control method for an electric vehicle is shown, the method comprising the following steps:

[0044] S1. In response to the triggering of the stationary steering command, determine whether the vehicle is in a preset vehicle operating condition. If so, control the steering controller to lock the steering wheel. Specifically, in this embodiment, the driver can initiate a stationary steering request command and a stationary steering direction request (clockwise or counterclockwise rotation, setting the rotation angle, etc.) through the large screen controller. At this time, the vehicle controller will determine the current status of the vehicle. Only when the vehicle is in a preset vehicle operating condition will the vehicle controller control the steering controller electrically connected to it to lock the steering wheel and activate the stationary steering function.

[0045] S2. Obtain the first tangential velocity of any front wheel of the vehicle and the second tangential velocity of the rear wheel diagonally opposite to the front wheel, and determine the compensation speed of the rear wheel based on the first and second tangential velocities, and determine the compensation torque based on the compensation speed. Specifically, in one embodiment, a first acceleration sensor is installed on the right front wheel of the vehicle body, and a second acceleration sensor is installed on the left rear wheel, wherein the longitudinal direction of the acceleration sensor is parallel to the wheelbase direction of the vehicle, and the lateral direction is coincident with the axis direction of the wheel. The vehicle controller obtains the first tangential velocity of the right front wheel and the second tangential velocity of the left rear wheel through the first acceleration sensor, calculates the compensation speed of the left rear wheel based on the first and second tangential velocities, and finally calculates the compensation torque based on the compensation speed. In another embodiment, the first acceleration sensor can also be installed on the left front wheel, and the corresponding second acceleration sensor is installed on the right rear wheel.

[0046] S3. Obtain the initial torque requested by the rear-wheel drive motor to drive the rear wheels, and determine the drive torque of the rear-wheel drive motor based on the initial torque and the compensation torque. Specifically, following the example in step S2, the vehicle controller obtains the initial torque requested by the rear-wheel drive motor to drive the left rear wheel. Then, the PID (Proportional Integral Derivative) control system in the vehicle controller can determine the drive torque allocated to the rear-wheel drive motor based on the initial torque and the compensation torque. The right front wheel still rotates with the initial torque, while the left rear wheel rotates with the drive torque, so that the first tangential speed and the second tangential speed are close in magnitude. This ensures that the vehicle's center of gravity does not shift significantly when turning in place on various surfaces, thus ensuring the safety and stability of turning in place.

[0047] Optionally, the determination of whether the vehicle is in a preset vehicle operating condition in step S2, and if so, controlling the steering controller to lock the steering wheel, includes: determining whether the vehicle's brake pedal is depressed and whether the vehicle's current speed is zero. If the brake pedal is depressed and the current speed is zero, the vehicle controller sends a steering wheel lock request to the steering controller. In response to the triggering of the steering wheel lock request, the steering controller adjusts the steering wheel to the zero position and locks the steering wheel when the steering angle is less than or equal to a preset angle threshold. Specifically, in this embodiment, the preset vehicle operating condition is that the vehicle is stationary (current speed is zero) and the brake pedal is depressed. In actual implementation, the vehicle controller determines whether the brake pedal is depressed based on the brake pedal position signal. When the vehicle is in a preset vehicle operating condition, the vehicle controller sends a steering wheel lock request to the electrically connected steering controller. Upon receiving this request, the steering controller automatically adjusts the steering wheel to the zero position. When the steering controller rotates the steering wheel to a position where the steering angle is less than or equal to a preset angle threshold, it locks the steering wheel. After the steering wheel is locked, the vehicle controller activates the stationary steering function. Furthermore, the steering controller also sends a steering wheel lock signal back to the vehicle controller to further confirm that the steering wheel is locked, preventing accidental steering wheel activation during stationary steering due to steering controller malfunction or other reasons, which could lead to safety hazards such as collisions with pedestrians, oncoming vehicles, or loss of control. Preferably, the preset angle threshold is 2°.

[0048] Optionally, after locking the steering wheel when the steering wheel angle is less than or equal to a preset angle threshold as described above, the process includes: responding to the triggering of the stationary steering exit command, determining whether the vehicle's brake pedal is depressed and whether the vehicle's current speed is zero; if the brake pedal is depressed and the current speed is zero, controlling the vehicle controller to send a steering wheel unlock request to the steering controller; and responding to the triggering of the steering wheel unlock request, controlling the steering controller to unlock the steering wheel. Specifically, in this embodiment, during or after stationary steering, an exit stationary steering request command can be initiated through the large screen controller. Only when the vehicle is in the preset vehicle operating condition described above will the vehicle controller send a steering wheel unlock request to the steering controller, which is electrically connected to it. After receiving the request, the steering controller unlocks the steering wheel, and after the steering wheel is unlocked, the vehicle controller exits the stationary steering function. In addition, the steering controller will also send a steering wheel unlock signal back to the vehicle controller to further confirm that the current state of the steering wheel is unlocked. At this time, the driver can operate the steering wheel for normal driving, thereby improving the safety of stationary steering.

[0049] Optionally, determining the compensation speed of the rear wheel based on the first tangential speed and the second tangential speed in step S2, and determining the compensation torque based on the compensation speed, includes: determining the difference between the first tangential speed and the second tangential speed as the compensation speed, and controlling the vehicle controller to determine the compensation torque based on the compensation speed. Specifically, regardless of the direction of the speed, the vehicle controller defines the difference between the values ​​of the first tangential speed and the second tangential speed as the compensation speed. It is understandable that when the front and rear wheels of the vehicle are on roads with different road surface adhesion coefficients, the values ​​of the first tangential speed of the front wheel and the second tangential speed of the rear wheel are different. For example, if the right front wheel of the vehicle is on sand and the left rear wheel is on concrete, due to the difference in road surface adhesion coefficients (the static friction coefficient between the tire and the road surface), during a stationary turn, the first tangential speed of the right front wheel must be greater than the second tangential speed of the left rear wheel before the right front wheel leaves the sand. The larger the difference between the tangential speeds, the greater the offset of the vehicle's center of gravity, and the worse the stability and safety of the vehicle when turning in place. In this embodiment, the difference between the first tangential speed and the second tangential speed is determined as the compensation speed. The vehicle controller, controlling its electrically connected PID control system, determines the compensation torque based on the compensation speed, and then distributes the compensation torque to the drive torque of the rear-wheel drive motor. At this time, the right front wheel continues to rotate with the initial torque, while the left rear wheel rotates with the drive torque, thereby achieving a speed close in magnitude between the first and second tangential speeds, improving the safety and stability of the vehicle's stationary turning.

[0050] Please refer to Figure 3 , Figure 3A schematic diagram illustrating the tangential velocity of an electric vehicle during a stationary turn is shown. Step S2, which involves obtaining the first tangential velocity of any front wheel and the second tangential velocity of the rear wheel diagonally opposite the front wheel, includes: obtaining the first lateral acceleration and the first longitudinal acceleration of the front wheel, and determining the first tangential acceleration based on the first lateral acceleration and the first longitudinal acceleration; obtaining the second lateral acceleration and the second longitudinal acceleration of the rear wheel, and determining the second tangential acceleration based on the second lateral acceleration and the second longitudinal acceleration; obtaining the current speed of the vehicle, determining the first tangential velocity based on the current speed and the first tangential acceleration, and determining the second tangential velocity based on the current speed and the second tangential acceleration. Specifically, the acceleration sensor can detect the lateral acceleration and longitudinal acceleration of the vehicle. For example, a first acceleration sensor is installed on the right front wheel of the vehicle, and a second acceleration sensor is installed on the left rear wheel. The first acceleration sensor detects the lateral acceleration and longitudinal acceleration of the right front wheel as a1lat(t) and a1long(t), respectively, and the second acceleration sensor detects the lateral acceleration and longitudinal acceleration of the left rear wheel as a2lat(t) and a2long(t), respectively. Using the Pythagorean theorem, the first tangential acceleration of the right front wheel and the second tangential acceleration of the left rear wheel when the vehicle is turning in place can be calculated. Second tangential acceleration Based on the tangential acceleration, the vehicle's current speed, and the speed formula V = V0 + at, the tangential velocities of the vehicle's right front wheel and left rear wheel can be calculated separately. The first tangential velocity... Second tangential velocity Preferably, each time the vehicle performs a stationary turn, in order to eliminate the error caused by integration, the vehicle controller will reset the first tangential velocity and the second tangential velocity retained during the previous stationary turn to zero.

[0051] Optionally, obtaining the vehicle's current speed as described above includes: calculating the accelerator pedal opening based on the operating voltage output by the accelerator pedal, and determining the current speed based on the accelerator pedal opening. Specifically, in this embodiment, the vehicle includes a first accelerator pedal sensor and a second accelerator pedal sensor for acquiring output voltage based on the accelerator pedal travel. The vehicle controller is electrically connected to both the first and second accelerator pedal sensors. The output voltage acquired by the first accelerator pedal sensor is U1, and the output voltage acquired by the second accelerator pedal sensor is U2. The vehicle controller calculates the accelerator pedal opening based on the output voltages U1 and U2. The Electronic Stability Control (ESC) system provides the vehicle's current speed to the vehicle controller based on the accelerator pedal opening.

[0052] Please refer to Figure 4 , Figure 4This diagram illustrates the relationship between the stationary turning angular velocity of an electric vehicle and the accelerator pedal opening. Furthermore, the stationary turning angular velocity increases with increasing accelerator pedal opening, rather than being a fixed value. Understandably, before the driver depresses the accelerator pedal, three control modes can be selected. The first curve (first control mode) shows that as the accelerator pedal opening gradually increases, the rate of increase in the stationary turning angular velocity decreases from high to low, resulting in a higher turning angular velocity in the initial stage, suitable for more aggressive drivers (e.g., areas with heavy traffic requiring rapid stationary turns). The second curve (second control mode) shows that as the accelerator pedal opening gradually increases, the rate of increase in the stationary turning angular velocity remains constant, suitable for more conventional drivers. The third curve (third control mode) shows that as the accelerator pedal opening gradually increases, the rate of increase in the stationary turning angular velocity increases from low to high, resulting in a lower turning angular velocity in the initial stage, suitable for more conservative drivers (e.g., situations where babies, children, the elderly, or patients are in the vehicle). In practical applications, drivers can choose any of the three control methods according to the actual situation, giving them greater flexibility.

[0053] Optionally, obtaining the initial torque requested by the rear-wheel drive motor for driving the rear wheels in step S3 includes: determining the total requested torque of all drive motors based on the accelerator pedal opening; obtaining the vehicle's maximum drivable torque and maximum permissible drive torque; determining the minimum value among the total requested torque, maximum drivable torque, and maximum permissible drive torque as the total torque to be allocated; and determining the quotient obtained by dividing the total torque to be allocated by the total number of wheels of the vehicle as the initial torque. Specifically, in this embodiment, the vehicle controller obtains the total requested torque of the four drive motors by looking up a table based on the accelerator pedal opening. Simultaneously, the vehicle controller obtains the maximum drivable torque and maximum permissible drive torque stored in the system for limiting the total requested torque. The minimum value among the three is determined as the total torque to be allocated to the four drive motors to limit the maximum speed of the vehicle when turning in place, thereby improving the safety and stability when turning in place. Further, the quotient obtained by dividing the total torque to be allocated by four is the initial torque requested by each drive motor. Preferably, when the direction of the initial torque requested by the drive motor is positive, the drive motor rotates forward; conversely, when the direction is negative, the drive motor rotates backward. For example, when the driver requests a clockwise turn while stationary, the drive motors for the left front and left rear wheels request an initial torque in the positive direction, causing the left front and left rear wheels to rotate forward. Conversely, the drive motors for the right front and right rear wheels request an initial torque in the negative direction, causing the right front and right rear wheels to rotate backward. This achieves a clockwise turn while stationary. The principle is the same when the turn request is counter-clockwise, and will not be repeated here.

[0054] Please refer to Figure 5 , Figure 5 This diagram illustrates a process where a vehicle controller sends a torque request to a drive motor. Step S3, determining the drive torque of the rear-wheel drive motor based on the initial torque and the compensation torque, includes summing the initial torque and the compensation torque to determine the drive torque. Specifically, the vehicle controller sums the compensation torque determined by the PID control system in step S2 with the initial torque requested by the rear-wheel drive motor to determine the drive torque allocated to the rear-wheel drive motor. In this embodiment, a first acceleration sensor is located on the right front wheel, and a second acceleration sensor is located on the left rear wheel. The PID control system determines the compensation speed based on the first tangential velocity of the right front wheel and the second tangential velocity of the left rear wheel, and then determines the compensation torque based on the compensation speed. The vehicle controller then acquires the initial torque requested by the left rear-wheel drive motor and sums it with the compensation torque; the sum is the drive torque of the left rear-wheel drive motor. Simultaneously, the drive torques of the left front wheel, right front wheel, and right rear wheel drive motors are all the initial torques as described above (the quotient obtained by dividing the total torque to be allocated by four). By dynamically adjusting the drive torque of the left rear wheel (or right rear wheel) drive motor according to the difference in tangential speeds of the wheels distributed diagonally, the first tangential speed and the second tangential speed are made close in magnitude. This ensures that the vehicle's center of gravity does not shift significantly when turning in place on various surfaces, thus ensuring the safety and stability of turning in place.

[0055] Optionally, obtaining the initial torque requested by the rear-wheel drive motor for driving the rear wheels in step S3 further includes: obtaining the road surface adhesion coefficient of the road where the vehicle is located, and determining the initial torque based on the road surface adhesion coefficient. Specifically, in this embodiment, the road surface adhesion coefficient of the road where the vehicle is currently located is determined by sensors installed on the vehicle in cooperation with the vehicle controller, and the initial torque requested by the four drive motors is determined by the magnitude of the road surface adhesion coefficient. For example, when the road surface adhesion coefficient is large, it means that the friction between the four wheels and the ground is large. In order to enable the vehicle to obtain better stability during stationary turning, the initial torque requested by the four drive motors is correspondingly increased to overcome the friction. Conversely, when the road surface adhesion coefficient is small, the initial torque requested by the four drive motors is correspondingly reduced to avoid excessive vehicle speed causing tire slippage, which would affect the stability of the vehicle during stationary turning, and also save the power of the vehicle's power battery.

[0056] The present invention also provides an electric vehicle equipped with a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steering control method for the electric vehicle as described above, achieving the same beneficial effects. In one embodiment, the vehicle is further equipped with a large-screen controller electrically connected to the vehicle control unit (VCU), used by the driver to issue a request for the vehicle to turn in place and a request for the direction of the turn in place to the VCU.

[0057] 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 technical scope disclosed in this invention should be included within the scope of protection of this invention. Therefore, the scope of protection of this invention should be determined by the appended claims.

Claims

1. A steering control method of an electric vehicle, the vehicle comprising two front wheels and two rear wheels, the four wheels being driven by different drive motors, respectively, characterized by, The method comprises the following steps: In response to triggering of the spin-on-the-spot instruction, it is determined whether the vehicle is in a preset vehicle working condition, and if so, a steering controller is controlled to lock a steering wheel; A first tangential speed of any front wheel of the vehicle and a second tangential speed of a rear wheel diagonally arranged with the front wheel are obtained, and a compensation speed of the rear wheel is determined according to the first tangential speed and the second tangential speed, and a compensation torque is determined according to the compensation speed; An initial torque requested by a rear wheel driving motor for driving the rear wheel to rotate is obtained, and a driving torque of the rear wheel driving motor is determined according to the initial torque and the compensation torque.

2. The method of claim 1, wherein, The determination of whether the vehicle is in a preset vehicle working condition, and if so, the control of the steering controller to lock the steering wheel comprises: It is determined whether a brake pedal of the vehicle is depressed and whether a current speed of the vehicle is zero, and if the brake pedal is depressed and the current speed is zero, a vehicle controller is controlled to send a steering wheel locking request to the steering controller; In response to triggering of the steering wheel locking request, the steering controller is controlled to adjust the steering wheel to a zero position, and lock the steering wheel when a steering angle of the steering wheel is less than or equal to a preset angle threshold.

3. The method of claim 2, wherein, After the steering wheel is locked when the steering angle of the steering wheel is less than or equal to the preset angle threshold, the method comprises: In response to triggering of a spin-on-the-spot exit instruction, it is determined whether a brake pedal of the vehicle is depressed and whether a current speed of the vehicle is zero, and if the brake pedal is depressed and the current speed is zero, the vehicle controller is controlled to send a steering wheel unlocking request to the steering controller; In response to triggering of the steering wheel unlocking request, the steering controller is controlled to unlock the steering wheel.

4. The method of claim 2, wherein, The determination of the compensation speed of the rear wheel according to the first tangential speed and the second tangential speed, and the determination of the compensation torque according to the compensation speed comprises: A difference obtained by subtracting the second tangential speed from the first tangential speed is determined as the compensation speed, and the vehicle controller is controlled to determine the compensation torque according to the compensation speed.

5. The method of claim 1, wherein, The obtaining of the first tangential speed of any front wheel of the vehicle and the second tangential speed of a rear wheel diagonally arranged with the front wheel comprises: A first lateral acceleration and a first longitudinal acceleration of the front wheel are obtained, and a first tangential acceleration is determined according to the first lateral acceleration and the first longitudinal acceleration; A second lateral acceleration and a second longitudinal acceleration of the rear wheel are obtained, and a second tangential acceleration is determined according to the second lateral acceleration and the second longitudinal acceleration; A current speed of the vehicle is obtained, the first tangential speed is determined according to the current speed and the first tangential acceleration, and the second tangential speed is determined according to the current speed and the second tangential acceleration.

6. The method of claim 5, wherein, The obtaining of the current speed of the vehicle comprises: An acceleration pedal opening degree is calculated according to a working voltage output by an acceleration pedal, and the current speed is determined according to the acceleration pedal opening degree.

7. The method of claim 6, wherein, The obtaining of the initial torque requested by the rear wheel driving motor for driving the rear wheel to rotate comprises: determining a total requested torque of all the drive motors according to the accelerator pedal opening degree, obtaining a maximum drivable torque and a maximum allowable driving torque of the vehicle, and determining the minimum value among the total requested torque, the maximum drivable torque and the maximum allowable driving torque as a total torque to be distributed; determining a quotient obtained by dividing the total torque to be distributed by a total number of wheels of the vehicle as the initial torque.

8. The method of claim 1, wherein, the determining the driving torque of the rear wheel drive motor according to the initial torque and the compensation torque, comprises: determining a sum obtained by adding the initial torque and the compensation torque as the driving torque.

9. The method of claim 1, wherein, the obtaining the initial torque requested by the rear wheel drive motor for driving the rear wheel, further comprises: obtaining a road surface adhesion coefficient of a road on which the vehicle is located, and determining the initial torque according to the road surface adhesion coefficient.

10. An electric vehicle characterized by comprising: a computer program product, comprising a memory, a processor, and a computer program stored in the memory and capable of running on the processor, when the processor executes the computer program, the steps of the steering control method of the electric vehicle according to any one of claims 1 to 9 are implemented.

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