Control method and controller for automatic turning of electric vehicle and electric vehicle

Abstract

The invention discloses an electric vehicle automatic turning control method, a controller and an electric vehicle, and relates to the technical field of new energy automobiles. The control method is used for controlling the automatic U-turn function of the electric vehicle and comprises the steps that after a user selects the automatic U-turn function, the rotation angle of a steering wheel of the electric vehicle is detected; and after the rotation angle of the steering wheel is larger than the preset angle, responding to the situation that the opening degree of an accelerator pedal of the electric vehicle is larger than the preset accelerator opening degree, and starting the automatic turning-around function. Therefore, the driver can control the electric vehicle to turn around only through simple operation, the turning-around difficulty of the electric vehicle can be effectively reduced, and the driving experience of the user is improved.

Description

Technical Field

[0001] The present application relates to the technical field of new energy vehicles, and in particular to a control method and controller for automatic U-turn of an electric vehicle, and an electric vehicle. Background Art

[0002] When driving an electric vehicle, you often encounter situations where you need to turn the vehicle around. When making a conventional U-turn, the driver needs to repeatedly observe the surrounding road conditions and adjust the steering wheel, throttle and gear according to the actual driving situation to control the electric vehicle to move forward and backward, so as to slowly adjust the front of the electric vehicle to the desired driving direction. However, when making a U-turn on a narrow road or a road with complex road conditions, it is difficult for the driver to accurately control the body posture of the electric vehicle, which will further increase the difficulty of turning the electric vehicle and affect the user's driving experience.

[0003] Based on this, how to effectively reduce the difficulty of turning electric vehicles and improve the user's driving experience has become a technical problem that needs to be solved urgently. Summary of the invention

[0004] The present application provides a control method for automatic U-turn of an electric vehicle, a controller and an electric vehicle, which are used to reduce the difficulty of U-turn of the electric vehicle and improve the driving experience of the user.

[0005] To achieve the above objectives, the embodiments of the present application adopt the following technical solutions:

[0006] In a first aspect, a control method for automatic U-turn of an electric vehicle is provided, the control method being used to control the automatic U-turn function of the electric vehicle, the control method comprising: after a user selects the automatic U-turn function, detecting a turning angle of a steering wheel of the electric vehicle; after the turning angle of the steering wheel is greater than a preset angle, in response to an opening of an accelerator pedal of the electric vehicle being greater than a preset throttle opening, starting the automatic U-turn function.

[0007] In the above technical solution, after the user starts the automatic U-turn function, the steering wheel rotation angle can be detected first, and whether the user is ready to U-turn can be judged by detecting whether the steering wheel rotation angle is greater than the preset angle. After detecting that the steering wheel rotation angle is greater than the preset angle, it is further judged whether the user is currently ready to U-turn based on whether the opening of the accelerator pedal of the electric vehicle is greater than the preset throttle opening. Through double judgment, it is possible to avoid the user starting the U-turn function when he is not ready due to accidental touch, thereby ensuring the user's driving safety.

[0008] In addition, according to the technical solution provided in the embodiment of the present application, the driver only needs to perform simple operations to control the electric vehicle to make an automatic U-turn, which can effectively reduce the difficulty of turning the electric vehicle and improve the user's driving experience.

[0009] In any possible implementation of the first aspect, the control method further includes: after the user selects to turn around and before the steering wheel rotation angle is greater than a preset angle, setting the gear of the electric vehicle to a forward gear. In the above possible implementation, before starting the automatic U-turn function, the gear of the electric vehicle is first set to a forward gear, and then detecting whether the steering wheel rotation angle is greater than a preset angle to ensure that the electric vehicle is in a forward gear. When the gear position, steering wheel angle, and accelerator pedal opening meet the conditions, the automatic U-turn function can be started.

[0010] In any possible implementation of the first aspect, the control method further includes: after the user selects a U-turn, detecting the gear position of the electric vehicle; after the gear position of the electric vehicle is set to the forward gear, detecting the rotation angle of the steering wheel of the electric vehicle. In the above possible implementation, before starting the automatic U-turn function, the gear position of the electric vehicle is first detected. If the gear position is the forward gear, then detecting whether the rotation angle of the steering wheel is greater than a preset angle; if the gear position is not the forward gear, it is necessary to set the gear position to the forward gear and then detect whether the rotation angle of the steering wheel is greater than a preset angle to ensure that the electric vehicle is in the forward gear. When the gear position, steering wheel angle and accelerator pedal opening meet the conditions, the automatic U-turn function can be started.

[0011] In any possible implementation of the first aspect, the control method further includes: after starting the automatic U-turn function, locking one rear wheel of the electric vehicle, driving the two front wheels of the electric vehicle to rotate forwardly and driving the other rear wheel of the electric vehicle to rotate reversely to enable the electric vehicle to start turning around; stopping driving the two front wheels and the other rear wheel at the first moment after the electric vehicle starts turning around, unlocking the one rear wheel and locking the other rear wheel after the first moment, driving the two front wheels to rotate forwardly and driving the one rear wheel of the electric vehicle to rotate reversely to enable the electric vehicle to continue turning around. The above possible implementation method, after starting the automatic U-turn function, can make the electric vehicle rotate with the one rear wheel as the center, avoiding the electric vehicle from making unexpected movements during the U-turn process; stopping driving the two front wheels and the other rear wheel at the first moment after the electric vehicle starts to turn around, can make the electric vehicle be in a stationary state first, thereby unlocking the one rear wheel and locking the other rear wheel while remaining stationary, driving the two front wheels to rotate forward and driving the one rear wheel of the electric vehicle to rotate in the opposite direction, so that the electric vehicle can continue to turn with the other rear wheel as the center. In this way, the lateral distance of the electric vehicle during the U-turn process can be effectively reduced, so that the electric vehicle can also complete the automatic U-turn on the road section with limited lateral distance, avoiding the risk of scratches.

[0012] In any possible implementation of the first aspect, the control method further includes: at a second moment after the electric vehicle continues to turn around, stopping driving the two front wheels and the one rear wheel and unlocking the other rear wheel after the second moment so that the electric vehicle exits the automatic U-turn function. In the above possible implementation, in the process of controlling the electric vehicle to exit the automatic U-turn function, first stop driving the two front wheels and one rear wheel, and then unlock the other rear wheel, so that the electric vehicle can be stably stopped and exit the U-turn, thereby improving the safety of the electric vehicle during the U-turn process and improving the user's driving experience. If the other rear wheel is unlocked before the two front wheels and one rear wheel are stopped, the electric vehicle will move and jump out under the drive of the two front wheels and the left rear wheel, affecting the user's driving experience.

[0013] In any possible implementation of the first aspect, the control method specifically includes: after starting the automatic U-turn function, first locking the one rear wheel, and then driving the two front wheels to rotate forward and driving the other rear wheel to rotate reversely after locking the one rear wheel. The above possible implementation, after starting the automatic U-turn function, first locking the one rear wheel, and then driving the two front wheels to rotate forward and driving the other rear wheel to rotate reversely, can enable the electric vehicle to start turning in a stable state, which can improve the safety of the electric vehicle during the U-turn process and enhance the user's driving experience.

[0014] In any possible implementation of the first aspect, the control method specifically includes: after the first moment, first unlocking the one rear wheel and locking the other rear wheel of the electric vehicle, then driving the two front wheels of the electric vehicle to rotate forward and driving the one rear wheel of the electric vehicle to rotate reversely. In the above possible implementation, after the first moment, the locking wheel is switched first, and then the other three wheels are driven to rotate, which can ensure that the electric vehicle is stationary during the switching of the locking wheel, avoid unexpected deviation of the electric vehicle, and improve the driving safety of the user.

[0015] In any possible implementation of the first aspect, the control method specifically includes: after starting the automatic U-turn function, first controlling the wheel-end brake device corresponding to the one rear wheel to output a first braking force to lock the one rear wheel, and then controlling the wheel-end brake device to increase the braking force output to the one rear wheel to a second braking force in the process of driving the two front wheels to rotate forward so that the one rear wheel remains locked. In the above possible implementation, after starting the automatic U-turn function, before driving the two front wheels to rotate forward and driving the right rear wheel of the electric vehicle to rotate reversely, the drive motors corresponding to the two front wheels have not yet output torque, first controlling the wheel-end brake device corresponding to the one rear wheel to output a smaller first braking force to lock the first rear wheel, and in the process of driving the two front wheels to rotate forward and driving the other rear wheel of the electric vehicle to rotate reversely, controlling the wheel-end brake device to increase the braking force output to the one rear wheel to the second braking force to keep the one rear wheel locked.

[0016] In any possible implementation of the first aspect, the control method further includes: controlling the second braking force to increase as the positive torque output by the motors corresponding to the two front wheels increases. In the above possible implementation, after the automatic U-turn function is started, controlling the second braking force to increase as the positive torque output by the motors corresponding to the two front wheels increases can enable a locked rear wheel to remain locked, thereby preventing the electric vehicle from unexpectedly moving, thereby improving the reliability and stability of the electric vehicle's U-turn.

[0017] In any possible implementation of the first aspect, the control method specifically includes: after the first moment, controlling the torque output by the motor corresponding to the one rear wheel to decrease to zero at a first rate to unlock the one rear wheel; after unlocking the one rear wheel, controlling the torque output by the motor corresponding to the one rear wheel to increase from zero at a second rate greater than the first rate to drive the one rear wheel to rotate in the opposite direction. The above possible implementation can smoothly realize the switching of the locking wheel, avoid the sense of frustration during the switching process of the locking wheel, and improve the user's driving experience.

[0018] In any possible implementation of the first aspect, the control method further includes: in the process of controlling the electric vehicle to turn around, when the return angle of the steering wheel is greater than the preset return angle, the speed of the electric vehicle is greater than the preset speed, or the brake pedal opening of the electric vehicle is greater than the preset brake opening, controlling the electric vehicle to stop turning around. In the above possible implementation, when the return angle of the steering wheel is greater than the preset return angle, it means that the user has returned the steering wheel and hopes to stop the U-turn process of the electric vehicle. In this way, in response to the driver's operation, the control method provided in the embodiment of the present application will control the electric vehicle to stop turning around, thereby improving the flexibility of the automatic U-turn function to ensure the safety of the electric vehicle during the U-turn process.

[0019] In any possible implementation of the first aspect, the control method further includes: in the process of controlling the electric vehicle to turn around, when the user operates the accelerator pedal so that the opening of the accelerator pedal decreases from greater than the preset accelerator opening to less than the preset accelerator opening, the electric vehicle is controlled to stop turning around. In the above possible implementation, when the accelerator pedal opening decreases to less than the preset accelerator opening, it means that the user has released the accelerator pedal and hopes to stop the electric vehicle's U-turn process. At this time, in order to respond to the driver's operation, the control method provided in the present application will control the vehicle to stop turning around. For example, if the user finds that there is an obstacle on the U-turn path during the U-turn of the electric vehicle, the user can control the electric vehicle to stop turning around by releasing the accelerator pedal, thereby avoiding accidents.

[0020] In any possible implementation of the first aspect, the control method further includes: in the process of controlling the electric vehicle to turn around, controlling the speed of the electric vehicle not to change with the change of the opening of the accelerator pedal when the opening of the accelerator pedal is greater than the preset accelerator opening. In the above possible implementation, in the process of controlling the electric vehicle to turn around, the speed of the electric vehicle is kept at a constant rate or a preset rate, and the speed of the electric vehicle will not increase with the increase of the opening of the accelerator pedal, thereby ensuring that the electric vehicle completes the U-turn at a stable speed during the U-turn process, ensuring the stability and reliability of the electric vehicle during the U-turn process, and improving the user's driving experience.

[0021] In a second aspect, a controller for an electric vehicle is provided, wherein the controller is used to execute the control method described in the above-mentioned first aspect or any possible implementation manner of the first aspect.

[0022] In a third aspect, an electric vehicle is provided, comprising a drive system, a braking system and the controller provided in the second aspect, the drive system being used to drive the four wheels of the electric vehicle to rotate, the braking system being used to output braking force to the four wheels, and the controller being used to control the drive system and the braking system to execute the control method described in the first aspect or any possible implementation of the first aspect.

[0023] It can be understood that the beneficial effects that can be achieved by the controller and electric vehicle provided above can correspond to the beneficial effects of the control method for automatic U-turn of the electric vehicle provided above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of an electric vehicle turning around on the spot;

[0025] Figure 2 A schematic diagram of a leopard U-turn of an electric vehicle;

[0026] Figure 3 A schematic diagram of an electric vehicle provided in an embodiment of the present application;

[0027] Figure 4 A schematic diagram of the architecture of a four-motor distributed drive electric vehicle provided in an embodiment of the present application;

[0028] Figure 5 A schematic diagram of the architecture of a three-motor distributed drive electric vehicle provided in an embodiment of the present application;

[0029] Figure 6 A schematic diagram of the architecture of a two-motor driven electric vehicle provided in an embodiment of the present application;

[0030] Figure 7 A schematic diagram of activating the automatic U-turn function provided in an embodiment of the present application;

[0031] Figure 8 A schematic diagram of a U-turn process of an electric vehicle provided in an embodiment of the present application;

[0032] Fig. 9 A signal timing diagram of an electric vehicle U-turn process provided by an embodiment of the present application;

[0033] Fig.10 A schematic diagram of another electric vehicle U-turn process provided in an embodiment of the present application;

[0034] Fig.11 A schematic diagram of another electric vehicle U-turn process provided in an embodiment of the present application. DETAILED DESCRIPTION

[0035] The following will discuss the making and use of each embodiment in detail. However, it should be understood that many applicable inventive concepts provided by this application can be implemented in a variety of specific environments. The specific embodiments discussed are only illustrative of specific ways to implement and use this application and this technology, and do not limit the scope of this application.

[0036] Before introducing the embodiments of the present application, the application scenarios involved in the present application are first introduced and explained.

[0037] When an electric vehicle is driving, it is often necessary to control the electric vehicle to turn around. Conventional electric vehicle U-turn methods have a large U-turn radius and low U-turn efficiency. Especially when making a U-turn on a narrow road or a road with complex road conditions, it is difficult for users to use conventional methods to complete the U-turn of the electric vehicle when the lateral distance of the road is limited. Compared with conventional electric vehicle U-turn methods, the on-the-spot U-turn technology and the leopard U-turn technology can reduce the U-turn radius of the electric vehicle to a certain extent.

[0038] The following combination Figure 1 and Figure 2 , the on-the-spot U-turn technique and the leopard U-turn technique are introduced.

[0039] As a first example, refer to Figure 1 , Figure 1 The following is a schematic diagram of an electric vehicle turning around in place. Figure 1 Taking the direction shown in the figure as an example, the two wheels near the front of the vehicle are the two front wheels of the electric vehicle, and the two wheels near the rear of the vehicle are the two rear wheels of the electric vehicle. According to the left and right positions of the wheels, they can be divided into the left front wheel, the right front wheel, the left rear wheel and the right rear wheel. Figure 1 Take the arrow direction as an example. When the electric vehicle needs to turn right, the motor of the right front wheel and the motor of the right rear wheel respectively output reverse torque to reversely drive the right front wheel and the right rear wheel, and the motor of the left front wheel and the motor of the left rear wheel respectively output positive torque to positively drive the left front wheel and the left rear wheel. In this way, the electric vehicle can turn with the center of the electric vehicle itself as the center of the circle during the U-turn, and the U-turn radius is basically equivalent to half of the axial length of the electric vehicle itself.

[0040] As a second example, see Figure 2 , Figure 2 The example shows a schematic diagram of an electric vehicle turning around. During the entire turning process, the electric vehicle rotates from position 1 to position 2, and then from position 2 to position 3. Specifically, when the electric vehicle turns right, the front wheel motor outputs positive torque to drive the left front wheel and the right front wheel in the positive direction, and the rear wheel motor outputs reverse torque to drive the right rear wheel in the reverse direction, and the left rear wheel is braked and locked by the braking system. In this way, the electric vehicle can turn with the left rear wheel as the center during the turning process, and the turning radius is basically equivalent to half of the sum of the axial length of the electric vehicle and the body width.

[0041] In the first example above, although the turning radius of the on-the-spot U-turn scheme is small, it has high requirements on the driving configuration of the electric vehicle; in the second example above, although the leopard U-turn scheme does not have high requirements on the driving configuration of the electric vehicle, its turning radius is relatively large and the U-turn efficiency is low.

[0042] In view of this, the embodiments of the present application provide a control method, a controller and an electric vehicle for automatic U-turn of an electric vehicle. The control method provided by the present application detects the rotation angle of the steering wheel and the opening of the accelerator pedal, and activates the automatic U-turn function when the rotation angle of the steering wheel and the opening of the accelerator pedal meet the conditions, thereby effectively reducing the difficulty of U-turn of the electric vehicle and improving the driving experience of the user.

[0043] The electric vehicle provided in the embodiments of the present application will be described in detail below in conjunction with specific embodiments.

[0044] See also Figure 3 , Figure 3 A schematic diagram of an electric vehicle provided in an embodiment of the present application. Figure 3 As shown, the electric vehicle 01 includes a vehicle controller 10, a motor controller 20, a motor 30 and a power battery 40. The motor controller 20 and the motor 30 can be referred to as a drive system or a powertrain. The power battery 40 is used to supply power to the drive system. The motor controller 20 is used to control the output torque of the motor 30 according to the electric energy provided by the power battery 40. The vehicle controller 10 is used to send a torque signal to the motor controller 20, and the motor controller 20 can receive the torque signal and control the output torque of the motor 30 based on the torque signal, thereby driving the electric vehicle 01 to travel. Optionally, the electric vehicle 01 also includes a braking system ( Figure 3 (not shown), the braking system is used to provide braking force for the electric vehicle 01 when the electric vehicle 01 is in a braking state.

[0045] The running state of the electric vehicle includes a driving state and a braking state. The function of the vehicle controller 10 is described below in conjunction with the running state of the electric vehicle 01 .

[0046] When the electric vehicle 01 is in a driving state, the motor 30 in the driving system is used to provide driving force for the electric vehicle 01. Specifically, when the electric vehicle 01 is in a driving state, the vehicle controller 10 calculates the torque demand of the electric vehicle 01 according to the accelerator pedal opening indicated by the accelerator pedal, and outputs a torque signal to the motor controller 20. The motor controller 20 receives electric energy from the power battery 40 and controls the motor 30 to output the torque value indicated by the torque signal.

[0047] When the electric vehicle 01 is in a braking state, the drive system stops driving the wheels to rotate, and the braking system is used to provide braking force to the wheels so that the electric vehicle 01 can reduce the speed under the action of the braking force. In the braking state of the electric vehicle 01, the motor 30 in the electric vehicle 01 with energy recovery function can also be used to provide braking force for the electric vehicle 01. Specifically, when the electric vehicle 01 is in a braking state, the vehicle controller 10 receives a braking signal and sends an energy recovery instruction to the motor controller 20. The motor controller 20 controls the motor 30 to operate in a power generation state in response to the energy recovery instruction. The motor 30 converts the kinetic energy of the wheels of the electric vehicle 01 into electrical energy and outputs a reverse torque to the wheels of the electric vehicle 01 to provide braking force to the electric vehicle 01. Among them, the output of positive torque by the motor 30 means that the output direction of the motor 30 is the same as the rotational speed direction of the motor 30. The output of reverse torque by the motor 30 means that the output direction of the motor 30 is opposite to the rotational speed direction of the motor 30.

[0048] Optionally, the electric vehicle 01 may be a four-motor distributed drive electric vehicle (eg Figure 4 As shown), it can also be a three-motor distributed drive electric vehicle (as shown Figure 5 ), or an electric vehicle driven by two motors (such as Figure 6 shown).

[0049] In one example, if Figure 4 As shown, the electric vehicle 01 includes four motor controllers and four motors. The four motor controllers include motor controller 21, motor controller 22, motor controller 23 and motor controller 24. The four motors include motor 31, motor 32, motor 33 and motor 34. Motor controller 21 is used to control motor 31 to drive wheel 41, motor controller 22 is used to control motor 32 to drive wheel 42, motor controller 23 is used to control motor 33 to drive wheel 43, and motor controller 24 is used to control motor 34 to drive wheel 44.

[0050] In another example, Figure 5 As shown, the electric vehicle 01 includes three motor controllers and three motors. The three motor controllers include motor controller 21, motor controller 22 and motor controller 23. The three motors include motor 31, motor 32 and motor 33. Motor controller 21 is used to control motor 31 to drive wheel 41, motor controller 22 is used to control motor 32 to drive wheel 42, and motor controller 23 is used to control motor 33 to drive wheel 43 and wheel 44.

[0051] In another example, Figure 6 As shown, the electric vehicle 01 includes two motor controllers, two motors, and a braking system. The two motor controllers include a motor controller 21 and a motor controller 22. The two motors include a motor 31 and a motor 32. The motor controller 21 is used to control the motor 31 to drive wheels 41 and 42, and the motor controller 22 is used to control the motor 32 to drive wheels 43 and 44. The braking system mainly includes a brake pedal ( Figure 6 ), a brake controller 51 and four wheel-end brake devices 52. The brake controller 51 can generate a brake signal based on the opening of the brake pedal, and control one or more of the four wheel-end brake devices 52 to output a braking force to the corresponding wheel based on the indication of the brake signal, so as to prevent the wheel from rotating or prevent the tendency of the wheel to rotate. Furthermore, during the braking process of the electric vehicle 01, the greater the opening of the brake pedal, the greater the braking force indicated by the brake signal, the greater the braking force output by the wheel-end brake device 52, and the faster the speed of the electric vehicle 01 decreases.

[0052] Furthermore, the drive system, the brake system and the vehicle controller 10 can be connected to each other through a controller area network (CAN). For example, the vehicle controller 10 and the motor controller 20 in the drive system can communicate through a private CAN, the vehicle controller 10 and the brake controller 51 in the brake system can communicate through a public CAN, and the brake controller 51 in the brake system and each wheel-end brake device 52 can communicate through another private CAN. For another example, the vehicle controller 10 can also communicate with the motor controller 30 in the drive system and the brake controller 51 in the brake system respectively through the same CAN.

[0053] Optionally, the vehicle controller 10 can also obtain a driving mode signal through CAN, where the driving mode signal is used to indicate the current driving mode of the electric vehicle 01. For example, the driving mode may include one or more of a sports mode, a comfort mode, and an intelligent mode.

[0054] Optionally, the vehicle controller 10 may also obtain an electric vehicle gear signal through CAN, where the electric vehicle gear signal is used to indicate the current gear of the electric vehicle 01 , for example, the gear may include a forward gear, a reverse gear, etc.

[0055] The electric vehicle control method provided in the embodiment of the present application can be applied not only to the above-mentioned Figure 4 The electric vehicle with four motors distributed drive shown in FIG. 1 can also be applied to the above-mentioned Figure 5 The three-motor distributed drive electric vehicle shown or Figure 6 In the electric vehicle driven by two motors shown, the configuration requirements for the electric vehicle are low and the practicality is high. The relevant steps of the electric vehicle control method can be executed by the electric vehicle controller of the electric vehicle. Exemplarily, the relevant functions of the electric vehicle controller can be implemented by the above-mentioned whole vehicle controller and the motor controller in the drive system, or by the above-mentioned whole vehicle controller, the motor controller in the drive system and the brake controller in the brake system.

[0056] The architecture of the embodiment of the present application is described above. The electric vehicle automatic U-turn control method provided by the present application is described below in conjunction with a specific embodiment.

[0057] The control method of the embodiment of the present application includes: after the user selects the automatic U-turn function, controlling the electric vehicle to start the automatic U-turn function, controlling the electric vehicle to turn around, and controlling the electric vehicle to exit the automatic U-turn function.

[0058] The control method provided in this application is described in detail below in conjunction with specific embodiments.

[0059] Control the electric vehicle to start the automatic U-turn function.

[0060] The control method provided in the embodiment of the present application includes: after the user selects the automatic U-turn function, detecting the rotation angle of the steering wheel of the electric vehicle; after the rotation angle of the steering wheel is greater than a preset angle, in response to the opening of the accelerator pedal of the electric vehicle being greater than the preset throttle opening, starting the automatic U-turn function.

[0061] The user can select the automatic U-turn function in a variety of ways. For example, the electric vehicle 01 may be provided with a U-turn button for the user to operate to select the automatic U-turn function. The U-turn button may be a physical button, and the user may activate the U-turn function of the electric vehicle 01 by pressing the physical button. Figure 7 As shown, the U-turn button can also be a virtual button on the vehicle display screen or the central control display screen, and the user can select the virtual button through the vehicle display screen or the central control display screen to start the U-turn function of the electric vehicle 01. The vehicle controller or other controller of the electric vehicle 01 can be used to detect the angle of the steering wheel of the electric vehicle.

[0062] The preset angle and the preset throttle opening are triggering thresholds of the automatic U-turn function. For example, the preset angle may be 400 degrees, and the preset throttle opening may be 20%.

[0063] In one embodiment, the control method provided by the present application further includes: after the user selects the automatic U-turn function, detecting the gear position of the electric vehicle, and after the gear position of the electric vehicle is set to the forward gear, detecting the rotation angle of the steering wheel of the electric vehicle. That is to say, before starting the automatic U-turn function, the control method provided by the embodiment of the present application needs to detect the gear position of the electric vehicle in addition to detecting the rotation angle of the steering wheel to ensure that the electric vehicle is in the forward gear.

[0064] In another embodiment, the control method provided by the present application further includes: after the user selects the automatic U-turn function and before the steering wheel is turned at a greater angle than a preset angle, the gear of the electric vehicle is set to the forward gear. That is to say, the control method provided by the embodiment of the present application needs to activate the automatic U-turn function, and the user also needs to set the gear of the electric vehicle to the forward gear. That is to say, after the user selects the U-turn function, the gear needs to be adjusted to the forward gear, the steering wheel needs to be turned, and the accelerator pedal needs to be pressed to activate the automatic U-turn function.

[0065] Controlling the electric vehicle to turn around. Controlling the electric vehicle to turn around includes: locking one rear wheel of the electric vehicle, driving two front wheels of the electric vehicle to rotate forward and driving another rear wheel of the electric vehicle to rotate reversely, unlocking one rear wheel and locking the other rear wheel, and driving two front wheels to rotate forward and driving one rear wheel of the electric vehicle to rotate reversely.

[0066] In an embodiment of the present application, the control method provided by the present application includes: locking one rear wheel of the electric vehicle, driving the two front wheels of the electric vehicle to rotate forwardly and driving the other rear wheel of the electric vehicle to rotate reversely so that the electric vehicle starts to turn around; stopping driving the two front wheels and the other rear wheel at the first moment after the electric vehicle starts to turn around, unlocking one rear wheel and locking the other rear wheel after the first moment, driving the two front wheels to rotate forwardly and driving one rear wheel of the electric vehicle to rotate reversely so that the electric vehicle continues to turn around.

[0067] For ease of understanding, the following Figure 8 Taking the process of turning around the electric vehicle 01 as an example, the method provided in the embodiment of the present application is illustrated. Figure 8 The direction of the arrow shown in is right rotation, indicating that the user turns the steering wheel to the right to make the electric vehicle 01 complete a clockwise U-turn on the spot.

[0068] In one example, if Figure 8 As shown, before the electric vehicle 01 turns around, the electric vehicle 01 is at position 1. During the turning process of the electric vehicle 01, the left rear wheel of the electric vehicle 01 is locked, the two front wheels of the electric vehicle are driven to rotate forward, and the right rear wheel of the electric vehicle is driven to rotate reversely to make the electric vehicle start to turn around, so that the electric vehicle 01 turns from position 1 to position 2.

[0069] After the electric vehicle 01 reaches position 2, the driving of the two front wheels and the right rear wheel is stopped, and then the left rear wheel of the electric vehicle 01 is unlocked and the right rear wheel coaxial with the left rear wheel is locked. Thereafter, the two front wheels are driven to rotate forward and the left rear wheel is driven to rotate reversely so that the electric vehicle 01 rotates from position 1 to position 3, completing the U-turn of the electric vehicle 01.

[0070] from Figure 8 It can be seen that the lateral distance of the electric vehicle 01 during the U-turn is the axial length of the body of the electric vehicle 01 .

[0071] Figure 8 This is a schematic diagram of the electric vehicle 01 turning right to complete a U-turn. The process of the electric vehicle 01 turning left to complete a U-turn is similar to this, which will not be repeated here.

[0072] The control method provided in the embodiment of the present application requires locking and unlocking the rear wheels of the electric vehicle 01 during the process of controlling the electric vehicle 01 to turn around. The embodiment of the present application provides different methods for locking the rear wheels of the electric vehicle 01.

[0073] In one embodiment, the control method provided in the embodiment of the present application locks a rear wheel by controlling the rotational speed of a rear-drive motor corresponding to the rear wheel to zero so that the wheel speed of the rear wheel is zero. Specifically, the electric vehicle controller can output a speed signal to the motor controller of the rear-drive motor corresponding to the rear wheel; based on the speed signal, the motor controller controls the rotational speed of the rear-drive motor corresponding to the rear wheel to zero so that the rear wheel stops rotating. The speed signal is used to indicate that the motor controller operates in a speed mode and controls the rotational speed of the rear-drive motor to zero. Optionally, when the motor controller operates in the speed mode, the motor controller can sample the rotational speed of the rear-drive motor, and perform closed-loop control on the rear-drive motor based on the sampled value, so as to control the rotational speed of the rear-drive motor to zero. Figure 4 As an example, the electric vehicle 01 described above Figure 8 , during the movement of the electric vehicle 01 from position 1 to position 2, the motor controller 23 controls the speed of the motor 33 to be zero to lock the left rear wheel 43, and during the movement of the electric vehicle 01 from position 2 to position 3, the motor controller 24 controls the speed of the motor 34 to be zero to lock the right rear wheel 44. That is to say, during the movement of the electric vehicle 01 from position 1 to position 2, the motor 33 operates in the speed mode, with zero speed as the control target to lock the left rear wheel 43, and the motor 34 operates in the torque mode to output the reverse torque to drive the right rear wheel 44 to rotate in the opposite direction. During the movement of the electric vehicle 01 from position 2 to position 3, the motor 34 operates in the speed mode, with zero speed as the control target to lock the right rear wheel 44, and the motor 33 operates in the torque mode to output the reverse torque to drive the left rear wheel 43 to rotate in the opposite direction.

[0074] In another embodiment, the control method provided in the embodiment of the present application controls a wheel end brake device corresponding to a rear wheel to output a braking force to the rear wheel so that the wheel speed of the rear wheel is zero, thereby locking the rear wheel. Figure 6 Taking the electric vehicle shown in the figure as an example, the vehicle controller 10 can output a braking signal to the brake controller 51, and the brake controller 51 can control the wheel end brake device 52 corresponding to the left rear wheel 43 to output a braking force according to the instruction of the braking signal. The wheel end brake device 52 can gradually increase the output braking force until it exceeds the braking force threshold and then locks the left rear wheel 43, so that the left rear wheel 43 stops rotating. Figure 4 As an example, the electric vehicle 01 described above Figure 8 As shown, the electric vehicle 01 is in the process of turning right, and when the electric vehicle 01 moves from position 1 to position 2, the wheel-end brake device 52 outputs braking force to the left rear wheel 43 to lock the left rear wheel 43 . When the electric vehicle 01 moves from position 2 to position 3, the wheel-end brake device 52 outputs braking force to the right rear wheel 44 to lock the right rear wheel 44 .

[0075] In one embodiment, the control method provided in the embodiment of the present application specifically includes: after starting the automatic U-turn function, first locking one rear wheel, and after locking the one rear wheel, driving the two front wheels to rotate forward and driving the other rear wheel to rotate reversely.

[0076] The control method provided in the embodiment of the present application will lock one rear wheel before driving the electric vehicle 01 to rotate, so as to ensure that the electric vehicle 01 rotates with the rear wheel as the center and avoid unexpected movement of the electric vehicle 01, thereby improving the safety of the electric vehicle 01 during the U-turn and the driving experience of the driver. Figure 8 The electric vehicle 01 shown is in the process of turning right. After the automatic turning function is activated, the left rear wheel is locked first, and then the two front wheels are driven to rotate forward and the right rear wheel is driven to rotate reversely to move the electric vehicle 01 from position 1 to position 2.

[0077] In one embodiment, the control method provided in the embodiment of the present application specifically includes: after a first moment, first unlocking one rear wheel and locking another rear wheel of the electric vehicle, then driving the two front wheels of the electric vehicle to rotate forward and driving one rear wheel of the electric vehicle to rotate reversely.

[0078] Combination Figure 8 In the process of the electric vehicle 01 shown in FIG. 10A , when the electric vehicle 01 moves from position 1 to position 2, the driving of the two front wheels and the other rear wheel is stopped at the first moment. After the first moment, the left rear wheel is unlocked first and then the right rear wheel is locked. Then, the two front wheels of the electric vehicle are driven to rotate forward and one rear wheel of the electric vehicle is driven to rotate reversely. In this way, the two front wheels do not rotate during the switching process of the locked wheels, thereby avoiding unexpected movement of the electric vehicle 01.

[0079] In one embodiment, the control method provided in the embodiment of the present application specifically includes: after starting the automatic U-turn function, first controlling the wheel-end braking device corresponding to a rear wheel to output a first braking force to lock the rear wheel, and then controlling the wheel-end braking device to increase the braking force output to the rear wheel to a second braking force during the forward rotation of the two driven front wheels to keep the rear wheel locked.

[0080] Combination Figure 8 In the process of the electric vehicle 01 shown in FIG. 10A making a right U-turn, after the automatic U-turn function is activated, before driving the two front wheels to rotate forwardly and driving the right rear wheel of the electric vehicle to rotate reversely, the drive motors corresponding to the two front wheels have not yet output torque, and the wheel-end brake device corresponding to the left rear wheel is first controlled to output a smaller first braking force to lock the left rear wheel. In the process of driving the two front wheels to rotate forwardly and driving the right rear wheel of the electric vehicle to rotate reversely, the braking force output by the wheel-end brake device to the left rear wheel is controlled to increase to the second braking force to keep the left rear wheel locked.

[0081] In one embodiment, the control method provided in the embodiment of the present application specifically includes: in the process of driving the two front wheels of the electric vehicle to rotate forward, controlling the second braking force to increase as the forward torque output by the motors corresponding to the two front wheels increases.

[0082] Combination Figure 8 In the process of the electric vehicle 01 turning right, after the automatic U-turn function is activated, during the process of the electric vehicle 01 moving from position 1 to position 2, the second braking force is controlled to increase with the increase of the positive torque output by the motors corresponding to the two front wheels to ensure that the left rear wheel can remain locked, thereby avoiding unexpected movement of the electric vehicle 01 and improving the reliability and stability of the U-turn of the electric vehicle 01.

[0083] In one embodiment, the control method provided by the embodiment of the present application specifically includes: after a first moment, controlling the torque output by a motor corresponding to a rear wheel to decrease to zero at a first rate to unlock a rear wheel. After unlocking a rear wheel, controlling the torque output by a motor corresponding to a rear wheel to increase from zero at a second rate greater than the first rate to drive a rear wheel to rotate in the opposite direction.

[0084] Combination Figure 8 In the process of the electric vehicle 01 shown in the figure turning right, for the method of achieving wheel locking by zero speed control of the drive motor, after the first moment, the motor 33 corresponding to the left rear wheel 43 is first controlled to decrease to zero at a first rate to unlock the left rear wheel 43 and lock the right rear wheel 44, and then the motor 33 corresponding to the left rear wheel 43 is controlled to increase at a second rate greater than the first rate to drive one rear wheel to rotate in the opposite direction so that the electric vehicle 01 continues to turn around, thereby ensuring that the motor 33 can achieve a transition from zero speed mode to torque mode at a relatively gentle rate, avoiding the sense of frustration during the switching process of the locked wheel, and improving the user's driving experience.

[0085] In one embodiment, the control method provided in the embodiment of the present application further includes: in the process of controlling the electric vehicle to turn around, controlling the speed of the electric vehicle not to change with the change of the opening of the accelerator pedal when the opening of the accelerator pedal is greater than the preset accelerator opening. In other words, in the process of controlling the electric vehicle to turn around, the speed of the electric vehicle maintains a constant rate or a preset rate, and the speed of the electric vehicle does not increase with the increase of the opening of the accelerator pedal, thereby ensuring the stability and reliability of the electric vehicle 01 during the U-turn process.

[0086] In one embodiment, the control method provided by the embodiment of the present application also includes: in the process of controlling the wheel-end brake device corresponding to a rear wheel to output a braking force to lock a rear wheel, controlling the wheel-end brake device corresponding to a rear wheel to output a braking force that decreases as the adhesion coefficient between the rear wheel and the road surface decreases.

[0087] Combination Figure 8 In the process of the electric vehicle 01 turning right, when the wheel-end brake device of the left rear wheel is controlled to output the braking force to lock the left rear wheel, when the adhesion coefficient between the left rear wheel and the road surface decreases, the braking force output by the wheel-end brake device of the left rear wheel can be reduced accordingly to avoid excessive braking force causing the left rear wheel to lose friction with the road surface, thereby avoiding the left rear wheel from sliding. Therefore, the control method provided in the embodiment of the present application can set different braking force parameters according to different adhesion coefficients during the process of locking the wheel, thereby applying different braking forces according to different braking force parameters, thereby improving the driving safety of the user.

[0088] In another possible embodiment, when the front-drive motor outputs a positive torque to drive the two front wheels to rotate forwardly, the torque output by the front-drive motor is controlled to increase as the adhesion coefficient between the two front wheels and the road surface increases; when the other rear-drive motor outputs a negative torque to drive the other rear wheel to rotate reversely, the torque output by the other rear-drive motor is controlled to increase as the adhesion coefficient between the other rear wheel and the road surface increases.

[0089] Combination Figure 8 In the process of the electric vehicle 01 turning right, when the front-drive motor outputs a positive torque to drive the two front wheels (left front wheel and right front wheel) to rotate forward, the greater the adhesion coefficient between the two front wheels and the road surface, the greater the adhesion that the two front wheels can use. Therefore, a greater driving force can be output to ensure the normal rotation of the two front wheels on the road surface. In the process of the rear-drive motor of the right rear wheel outputting a reverse torque to drive the right rear wheel to rotate in the opposite direction, the greater the adhesion coefficient between the right rear wheel and the road surface, the greater the adhesion that the right rear wheel can use. Therefore, a greater reverse torque can be output to ensure that the right rear wheel can rotate normally in the opposite direction on the road surface.

[0090] Control the electric vehicle to exit the automatic U-turn function.

[0091] In one embodiment, the control method provided by the embodiment of the present application includes: stopping driving two front wheels and one rear wheel at a second moment after the electric vehicle continues to turn around and unlocking the other rear wheel after the second moment to enable the electric vehicle to exit the automatic U-turn function.

[0092] Combination Figure 8The electric vehicle 01 shown is in the process of turning right. At the second moment when the electric vehicle 01 reaches position 3, the electric vehicle completes the U-turn. The control method provided in the embodiment of the present application can control the electric vehicle to exit the automatic U-turn function. In the process of controlling the electric vehicle to exit the automatic U-turn function, first stop driving the two front wheels and the left rear wheel, and then unlock the right rear wheel. This allows the vehicle to stop stably and exit the U-turn, thereby improving the safety of the electric vehicle 01 during the U-turn process and improving the user's driving experience. If the right rear wheel is unlocked before stopping driving the two front wheels and the left rear wheel, the electric vehicle 01 will move and jump out under the drive of the two front wheels and the left rear wheel, affecting the user's driving experience.

[0093] In one embodiment, the control method provided in the present application includes: in the process of controlling the electric vehicle to turn around, when the return angle of the steering wheel is greater than a preset return angle, controlling the electric vehicle to stop turning around.

[0094] When the steering wheel return angle is greater than the preset return angle, it means that the user has returned the steering wheel and expects to stop the U-turn process of the electric vehicle 01. At this time, in response to the driver's operation, the control method provided in the embodiment of the present application will control the electric vehicle 01 to stop turning.

[0095] In another embodiment, the control method provided in the embodiment of the present application further includes: in the process of controlling the electric vehicle to turn around, when the speed of the electric vehicle is greater than a preset speed, controlling the electric vehicle to stop turning around.

[0096] When the speed of the electric vehicle 01 is greater than the preset speed, it means that the speed of the electric vehicle 01 is too high during the automatic U-turn of the electric vehicle. When turning at an excessively high speed, the body posture of the electric vehicle 01 is easily out of control, thus causing danger. In addition, turning at an excessively high speed will also cause panic to the driver. Therefore, the control method provided in the embodiment of the present application will control the electric vehicle to stop turning when the speed of the electric vehicle is greater than the preset speed to improve safety and enhance the user's sense of safety while driving. For example, the preset speed can be 10km / h. During the U-turn of the electric vehicle, if the speed exceeds this preset speed, the electric vehicle is controlled to stop turning.

[0097] In another embodiment, the control method provided in the embodiment of the present application also includes: in the process of controlling the electric vehicle to turn around, when the user operates the accelerator pedal so that the opening of the accelerator pedal decreases from greater than a preset throttle opening to less than a preset throttle opening, controlling the vehicle to stop turning around.

[0098] Exemplarily, when the accelerator pedal opening decreases to less than the preset accelerator opening, it means that the user has released the accelerator pedal and expects to stop the U-turn process of the electric vehicle 01. At this time, in response to the driver's operation, the control method provided in this application will control the vehicle to stop turning. For example, if the user finds an obstacle on the U-turn path during the U-turn process of the electric vehicle 01, the user can control the electric vehicle to stop turning by releasing the accelerator pedal to avoid accidents.

[0099] In another embodiment, the control method provided in the embodiment of the present application also includes: in the process of controlling the electric vehicle to turn around, when the brake pedal opening of the electric vehicle 01 is greater than the preset brake opening, stopping driving the four wheels of the electric vehicle 01.

[0100] For example, when the opening of the brake pedal is greater than the preset brake opening, it means that the user has stepped on the brake pedal and hopes to stop the U-turn process of the electric vehicle 01. At this time, in response to the driver's operation, the control method provided in the embodiment of the present application will control the electric vehicle to stop turning. In other words, in an emergency, the user can step on the brake pedal to control the electric vehicle 01 to stop turning.

[0101] Based on the above operations, when the controller of the electric vehicle detects that any one or more of the conditions of a change in the opening of the brake pedal, a change in the steering wheel angle, or a change in the opening of the accelerator pedal are met, the control method provided in the embodiment of the present application can flexibly control the electric vehicle 01 to exit the U-turn function, thereby improving the safety of the U-turn process of the electric vehicle 01.

[0102] Combine the following Fig. 9 And the specific embodiment describes in detail the process of controlling the electric vehicle to turn right on the spot.

[0103] The starting phase is from before time t1 to time t1. Before time t0, the user selects the automatic U-turn function and turns the steering wheel of the electric vehicle until the steering wheel angle is greater than the preset angle R1. At time t0, the user presses the accelerator pedal. At time t1 after time t0, the accelerator pedal opening is greater than the preset accelerator opening L1, and the automatic U-turn function is started.

[0104] The turning stage is from time t1 to time t5. At time t1, the automatic U-turn function is activated, and the braking system first outputs braking force to the left rear wheel to lock the left rear wheel. At time t2 after the left rear wheel is locked, the drive motors corresponding to the two front wheels begin to output torque to drive the electric vehicle to start turning. In the process of the drive motors corresponding to the two front wheels starting to output torque to drive the electric vehicle to start turning, the braking system continues to output braking force to the left rear wheel to keep the left rear wheel locked. It should be noted that after the automatic U-turn function is activated, the wheel-end brake device of the left rear wheel first outputs braking force to the left rear wheel to lock the left rear wheel, and then controls the electric vehicle 01 to start turning. This ensures that the left rear wheel is already in a locked state when the drive motors corresponding to the two front wheels start to output torque, avoiding the electric vehicle 01 from deviating from the original position due to the rear wheels not being locked.

[0105] In addition, after the automatic U-turn function is activated, from time t1 to time t2, the wheel-end brake device corresponding to the left rear wheel is first controlled to output the first braking force to lock the left rear wheel, and after time t2, the braking force output by the wheel-end brake device to the left rear wheel is controlled to increase to the second braking force to keep the left rear wheel locked. This is because from time t1 to time t2, the drive motors corresponding to the two front wheels have not yet output torque, so the wheel-end brake device corresponding to the left rear wheel only needs to output a smaller first braking force, and after time t2, the drive motors corresponding to the two front wheels begin to output torque, and the braking force output by the wheel-end brake device to the left rear wheel needs to increase to the second braking force to keep the left rear wheel locked.

[0106] From t2 to t3, the torque output by the drive motors corresponding to the two front wheels continues to increase, that is, from t2 to t3, the drive torque is being established. From t3 to t4, the torque output by the drive motors corresponding to the two front wheels is relatively stable, that is, from t3 to t4, the electric vehicle 01 is turning around stably.

[0107] At time t4, i.e. the first time, the electric vehicle 01 completes the first stage of turning, combined with Figure 8 , that is to say, the electric vehicle 01 turns to position 2 at time t4. The steering angle of the electric vehicle 01 can be any angle between 0° and 180°. For example, the steering angle can be 30°, 45°, 60°, 90°, 120°, 135° or 150°. The steering angle is related to the road conditions when the electric vehicle 01 turns around. For example, the steering angle can be determined based on the road conditions such as the width of the road and obstacles when the electric vehicle 01 turns around, or the steering angle can also be a steering angle preset by the user.

[0108] The switching phase is from time t4 to time t7, during which the locked wheel is switched from the left rear wheel to the right rear wheel.

[0109] From moment t4 to moment t5, the torque output by the drive motors corresponding to the two front wheels is controlled to gradually decrease to zero; from moment t5 to moment t6, the braking force output by the wheel-end brake device of the left rear wheel is controlled to gradually decrease to zero to unlock the left rear wheel; from moment t6 to moment t7, the braking force output by the wheel-end brake device of the right rear wheel is controlled to increase to lock the right rear wheel. At this time, the locking wheel of the electric vehicle 01 is switched from the left rear wheel to the right rear wheel.

[0110] In the switching stage, the control method provided in the embodiment of the present application first controls the torque output by the drive motors corresponding to the two front wheels to gradually decrease to zero, then controls the braking force output by the wheel-end brake device of the left rear wheel to gradually decrease to zero to unlock the left rear wheel, and finally controls the braking force output by the wheel-end brake device of the right rear wheel to increase to lock the right rear wheel. Thus, the two front wheels do not rotate during the switching process of the locked wheels, avoiding unexpected movement of the electric vehicle 01.

[0111] From time t7 to time t8 is the continued steering stage. From time t7 to time t8, the drive motors corresponding to the two front wheels continue to output torque, and the electric vehicle continues to turn with the right rear wheel as the center.

[0112] The exit phase is from time t8 to time t10.

[0113] At time t8, the electric vehicle 01 completes the U-turn, i.e., the second time, combined with Figure 8 , that is to say, the electric vehicle 01 rotates to position 3 at time t8, at which time the user releases the accelerator pedal until the accelerator pedal opening is less than the preset pedal opening. From time t8 to time t9, the torque output by the drive motors corresponding to the two front wheels begins to decrease to zero. After the torque output by the drive motors corresponding to the two front wheels begins to decrease to zero, at time t10, the braking force of the left rear wheel is controlled to decrease to zero to unlock the left rear wheel, and the electric vehicle 01 exits the U-turn function. In the process of the electric vehicle 01 exiting the U-turn function, it is also necessary to control the braking force of the left rear wheel to decrease to zero after the torque output by the drive motors corresponding to the two front wheels begins to decrease to zero to unlock the left rear wheel, thereby avoiding unexpected movement of the electric vehicle 01.

[0114] Fig.10 and Fig.11 Two other methods for realizing an electric vehicle U-turn on the spot are shown.

[0115] exist Fig.10In the example provided, before the electric vehicle 01 turns around, the electric vehicle 01 is in position 1. During the process of the electric vehicle 01 turning around, the right front wheel of the electric vehicle 01 is locked, the rear drive motor outputs reverse torque to drive the left rear wheel and the right rear wheel to rotate in the opposite direction, and the front drive motor outputs positive torque to drive the left front wheel to rotate in the positive direction. Under the rotation of the left front wheel, the left rear wheel and the right rear wheel, the electric vehicle 01 rotates from position 1 to position 2, rotating 90°. After the electric vehicle 01 reaches position 2, the drive system of the electric vehicle 01 first stops driving the four wheels of the electric vehicle 01, unlocks the right front wheel and locks the left front wheel coaxial with the right front wheel, and then the rear drive motors of the two rear wheels output reverse torque to drive the two rear wheels to rotate in the opposite direction, and the front drive motor of the right front wheel outputs positive torque to drive the right front wheel to rotate in the positive direction. The electric vehicle 01 rotates from position 2 to position 3 by 90° under the rotation of the right front wheel, the left rear wheel and the right rear wheel, completing the U-turn of the electric vehicle 01. At this time, the lateral distance of the electric vehicle 01 during the U-turn is the axial length of the electric vehicle 01. Fig.10 The control method of the electric vehicle 01 during the U-turn process is as described above and will not be repeated here.

[0116] exist Fig.11 In the example provided, before the electric vehicle 01 turns around, the electric vehicle 01 is in position 1, that is, the front of the vehicle faces Fig.11 As shown above. During the U-turn process of the electric vehicle 01, the left rear wheel of the electric vehicle 01 is locked, the front drive motors of the two front wheels output positive torque to drive the two front wheels to rotate forward, and the rear drive motor of the right rear wheel outputs reverse torque to drive the right rear wheel to rotate in the opposite direction. The electric vehicle 01 rotates from position 1 to position 2 by 90° under the rotation of the left front wheel, the right front wheel and the right rear wheel. After the electric vehicle 01 reaches position 2, the drive system of the electric vehicle 01 first stops driving the four wheels of the electric vehicle 01, unlocks the left rear wheel of the electric vehicle 01 and locks the left front wheel on the same side as the left rear wheel. After that, the front drive motor of the right front wheel outputs positive torque to drive the right front wheel to rotate forward, and the rear drive motors of the two rear wheels output reverse torque to drive the two rear wheels to rotate in the opposite direction. Under the rotation of the right front wheel, the left rear wheel and the right rear wheel, the electric vehicle 01 rotates from position 2 to position 3 by 90°, completing the U-turn of the electric vehicle 01. At this time, the lateral distance of the electric vehicle 01 during the U-turn is the axial length of the electric vehicle 01 . Fig.11 The control method of the electric vehicle 01 during the U-turn process is as described above and will not be repeated here.

[0117] In another embodiment of the present application, an electric vehicle controller for an electric vehicle is provided. The electric vehicle controller is used to control the electric vehicle to realize an automatic U-turn function.

[0118] In another embodiment of the present application, an electric vehicle is also provided, which includes a drive system, a braking system and a controller provided in the above embodiment, the drive system is used to drive the four wheels of the electric vehicle to rotate, the braking system is used to output braking force to the four wheels, and the controller is used to control the drive system and the braking system to realize the automatic U-turn function of the electric vehicle.

[0119] It can be understood that all relevant contents of each step involved in the above method embodiment can be referred to the embodiment of the controller and the embodiment of the electric vehicle, and the embodiments of the present application will not be repeated here.

[0120] Finally, it should be noted that the above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A control method for automatic U-turn of an electric vehicle, characterized in that: The control method is used to control the automatic U-turn function of the electric vehicle, and the control method includes: After the user selects the automatic U-turn function, detecting the rotation angle of the steering wheel of the electric vehicle; After the steering wheel is turned at a rotation angle greater than a preset angle, in response to the accelerator pedal opening of the electric vehicle being greater than a preset accelerator opening, the automatic U-turn function is activated.

2. The control method according to claim 1, characterized in that: The control method further comprises: After the user selects to turn around and before the steering wheel is turned at a angle greater than a preset angle, the gear position of the electric vehicle is set to a forward gear.

3. The control method according to claim 1 or 2, characterized in that: The control method further comprises: After the user selects to turn around, detecting the gear position of the electric vehicle; After the gear position of the electric vehicle is set to a forward gear, a rotation angle of a steering wheel of the electric vehicle is detected.

4. The control method according to claim 1 or 2, characterized in that: The control method further comprises: After the automatic U-turn function is activated, one rear wheel of the electric vehicle is locked, two front wheels of the electric vehicle are driven to rotate forwardly, and another rear wheel of the electric vehicle is driven to rotate reversely so that the electric vehicle starts to turn around; At the first moment after the electric vehicle starts to turn around, the driving of the two front wheels and the other rear wheel is stopped, and after the first moment, the one rear wheel is unlocked and the other rear wheel is locked, the two front wheels are driven to rotate forwardly and the one rear wheel of the electric vehicle is driven to rotate reversely so that the electric vehicle continues to turn around.

5. The control method according to claim 4, characterized in that: The control method further comprises: At a second moment after the electric vehicle continues to make a U-turn, driving of the two front wheels and the one rear wheel is stopped and the other rear wheel is unlocked after the second moment to enable the electric vehicle to exit the automatic U-turn function.

6. The control method according to claim 4, characterized in that: The control method specifically includes: After the automatic U-turn function is started, the one rear wheel is locked first, and then the two front wheels are driven to rotate forwardly and the other rear wheel is driven to rotate reversely.

7. The control method according to claim 4, characterized in that: The control method specifically includes: After the first moment, the one rear wheel is unlocked and the other rear wheel of the electric vehicle is locked, and then the two front wheels of the electric vehicle are driven to rotate forward and the one rear wheel of the electric vehicle is driven to rotate reversely.

8. The control method according to claim 6, characterized in that: The control method specifically includes: After starting the automatic U-turn function, the wheel-end brake device corresponding to the one rear wheel is first controlled to output a first braking force to lock the one rear wheel, and then while driving the two front wheels to rotate forward, the wheel-end brake device is controlled to increase the braking force output to the one rear wheel to a second braking force to keep the one rear wheel locked.

9. The control method according to claim 8, characterized in that: The control method further comprises: The second braking force is controlled to increase as the positive torque output by the motors corresponding to the two front wheels increases.

10. The control method according to claim 4, characterized in that: The control method specifically includes: After the first moment, controlling the torque output by the motor corresponding to the one rear wheel to decrease to zero at a first rate to unlock the one rear wheel; After unlocking the one rear wheel, the torque output by the motor corresponding to the one rear wheel is controlled to increase from zero at a second rate greater than the first rate to drive the one rear wheel to rotate in the opposite direction.

11. The control method according to claim 1, characterized in that: The control method further comprises: During the process of controlling the electric vehicle to turn around, when the steering wheel return angle is greater than a preset return angle, the speed of the electric vehicle is greater than a preset speed, or the brake pedal opening of the electric vehicle is greater than a preset brake opening, the electric vehicle is controlled to stop turning around.

12. The control method according to claim 1, characterized in that: The control method further comprises: In the process of controlling the electric vehicle to turn around, when the user operates the accelerator pedal so that the opening of the accelerator pedal decreases from greater than the preset accelerator opening to less than the preset accelerator opening, the electric vehicle is controlled to stop turning around.

13. The control method according to claim 1, characterized in that: The control method further comprises: In the process of controlling the electric vehicle to turn around, the speed of the electric vehicle is controlled not to change with the change of the opening of the accelerator pedal when the opening of the accelerator pedal is greater than the preset accelerator opening.

14. A controller for an electric vehicle, characterized in that: The controller is used to execute the control method according to any one of claims 1 to 13.

15. An electric vehicle, characterized in that: The electric vehicle includes a drive system, a braking system and a controller as described in claim 14, wherein the drive system is used to drive the four wheels of the electric vehicle to rotate, the braking system is used to output braking force to the four wheels, and the controller is used to control the drive system and the braking system to perform the control method as described in any one of claims 1 to 13.

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