Control method for automatic u-turn of electric vehicle, controller, and electric vehicle

Abstract

A control method for automatic U-turn of an electric vehicle (01), comprising: when a user selects an automatic U-turn function, detecting the rotation angle of a steering wheel of the electric vehicle; and when the rotation angle of the steering wheel is greater than a preset angle, in response to the opening degree of an accelerator pedal of the electric vehicle being greater than a preset accelerator opening degree, enabling the automatic U-turn function. Also disclosed are a controller and an electric vehicle. By means of the control method, a driver only needs to perform a simple operation to control the electric vehicle to achieve a U-turn, thereby effectively reducing the difficulty of the U-turn of the electric vehicle, and improving the driving experience of the user.

Description

A control method, controller, and electric vehicle for automatic U-turn of electric vehicles

[0001] This application claims priority to Chinese Patent Application No. 202411550862.1, filed with the State Intellectual Property Office of China on October 31, 2024, entitled "A Control Method, Controller and Electric Vehicle for Automatic U-Turning of an Electric Vehicle", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of new energy vehicle technology, and in particular to a control method, controller, and electric vehicle for automatic U-turn of an electric vehicle. Background Technology

[0003] During the driving of electric vehicles, situations often require U-turns. A typical U-turn requires the driver to repeatedly observe the surrounding road conditions and, based on the actual driving situation, adjust the steering wheel, accelerator, and gear to control the electric vehicle's forward and backward movement, gradually adjusting the vehicle's orientation to the desired direction. However, when making U-turns on narrow roads or in complex road conditions, the driver finds it difficult to accurately control the electric vehicle's posture, further increasing the difficulty of the U-turn and impacting the user's driving experience.

[0004] Therefore, how to effectively reduce the difficulty of turning electric vehicles and improve the user's driving experience has become an urgent technical problem to be solved. Summary of the Invention

[0005] This application provides a control method, controller, and electric vehicle for automatic U-turn of electric vehicles, which reduces the difficulty of U-turns for electric vehicles and improves the user's driving experience.

[0006] To achieve the above objectives, the embodiments of this application adopt the following technical solutions:

[0007] In a first aspect, a control method for automatic U-turn of an electric vehicle is provided. The control method is used to control the automatic U-turn function of the electric vehicle. 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 rotation angle of the steering wheel is greater than a preset angle, in response to the opening degree of the accelerator pedal of the electric vehicle being greater than a preset accelerator opening degree, activating the automatic U-turn function.

[0008] In the above technical solution, after the user activates the automatic U-turn function, the steering wheel rotation angle can be detected first. By detecting whether the steering wheel rotation angle is greater than a preset angle, it can be determined whether the user is ready to make a U-turn. After detecting that the steering wheel rotation angle is greater than the preset angle, it can be further determined whether the user is ready to make a U-turn based on whether the opening of the accelerator pedal of the electric vehicle is greater than the preset accelerator opening. Thus, through dual judgment, it can avoid the user activating the U-turn function before being ready due to accidental touch, and ensure the user's driving safety.

[0009] Furthermore, according to the technical solution provided in the embodiments of this application, the driver only needs to perform simple operations to control the electric vehicle to achieve automatic U-turn, which can effectively reduce the difficulty of U-turns for electric vehicles and improve the user's driving experience.

[0010] In any possible implementation of the first aspect, the control method further includes: after the user selects to make a U-turn and before the steering wheel rotation angle is greater than a preset angle, setting the gear of the electric vehicle to forward gear. In the above possible implementation, before activating the automatic U-turn function, the gear of the electric vehicle is first set to forward gear, and then the steering wheel rotation angle is checked to ensure that the electric vehicle is in forward gear. When the gear position, steering wheel angle, and accelerator pedal opening all meet the conditions, the automatic U-turn function can be activated.

[0011] In any possible implementation of the first aspect, the control method further includes: after the user selects to make a U-turn, detecting the gear position of the electric vehicle; and after the gear position of the electric vehicle is set to drive, detecting the steering wheel rotation angle of the electric vehicle. In the above possible implementation, before activating the automatic U-turn function, the gear position of the electric vehicle is detected. If the gear position is drive, the steering wheel rotation angle is checked to see if it is greater than a preset angle. If the gear position is not drive, the steering wheel rotation angle is checked again after setting the gear to drive to ensure that the electric vehicle is in drive. The automatic U-turn function can be activated when the gear position, steering wheel angle, and accelerator pedal opening all meet the conditions.

[0012] In any possible implementation of the first aspect, the control method further includes: after activating the automatic U-turn function, locking one rear wheel of the electric vehicle, driving the two front wheels of the electric vehicle to rotate forward and driving the other rear wheel of the electric vehicle to rotate in reverse to cause the electric vehicle to begin U-turn; stopping the driving of the two front wheels and the other rear wheel at a first moment after the electric vehicle begins U-turn, and unlocking the one rear wheel and locking the other rear wheel after the first moment, driving the two front wheels to rotate forward and driving the one rear wheel of the electric vehicle to rotate in reverse to cause the electric vehicle to continue U-turn. The aforementioned possible implementation, after activating the automatic U-turn function, allows the electric vehicle to rotate around one rear wheel as the center, preventing unexpected movement during the U-turn. By stopping the driving of the two front wheels and the other rear wheel immediately after the U-turn begins, the electric vehicle can initially come to a standstill. While remaining stationary, one rear wheel can be unlocked and the other locked, while the two front wheels rotate forward and the other rear wheel rotates in the opposite direction, allowing the electric vehicle to continue turning around the other rear wheel as the center. This effectively reduces the lateral distance of the electric vehicle during the U-turn, enabling it to complete automatic U-turns even on road sections with limited lateral distance, thus avoiding the risk of collisions.

[0013] In any possible implementation of the first aspect, the control method further includes: stopping the driving of the two front wheels and the one rear wheel at a second moment after the electric vehicle continues to make a U-turn, and unlocking the other rear wheel after the second moment to allow the electric vehicle to exit the automatic U-turn function. In the above possible implementation, during the process of controlling the electric vehicle to exit the automatic U-turn function, the driving of the two front wheels and one rear wheel is stopped first, and then the other rear wheel is unlocked. This allows the electric vehicle to stop stably and exit the U-turn, thereby improving the safety of the electric vehicle during the U-turn process and enhancing the user's driving experience. If the other rear wheel is unlocked before the driving of the two front wheels and one rear wheel has stopped, the electric vehicle will lurch forward under the drive of the two front wheels and the left rear wheel, affecting the user's driving experience.

[0014] In any possible implementation of the first aspect, the control method specifically includes: after activating the automatic U-turn function, first locking one rear wheel, and then driving the two front wheels to rotate forward and driving the other rear wheel to rotate in the opposite direction. The above possible implementation, by first locking one rear wheel after activating the automatic U-turn function, and then driving the two front wheels to rotate forward and driving the other rear wheel to rotate in the opposite direction, enables the electric vehicle to begin turning under stable conditions, thereby improving the safety of the electric vehicle during the U-turn process and enhancing the user's driving experience.

[0015] In any possible implementation of the first aspect, the control method specifically includes: after the first moment, first unlocking 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 in the reverse direction. This possible implementation, by completing the switching of the locked wheel after the first moment before driving the other three wheels to rotate, ensures that the electric vehicle remains stationary during the switching of the locked wheel, preventing unexpected deviations and improving user safety.

[0016] In any possible implementation of the first aspect, the control method specifically includes: after activating the automatic U-turn function, first controlling the wheel-end braking device corresponding to the rear wheel to output a first braking force to lock the rear wheel; then, during the process of driving the two front wheels to rotate forward, controlling the braking force output by the wheel-end braking device to the rear wheel to increase to a second braking force so that the rear wheel remains locked. In the above possible implementation, after activating 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 in the opposite direction, the drive motors corresponding to the two front wheels have not yet output torque. First, controlling the wheel-end braking device corresponding to the rear wheel to output a small first braking force to lock the first rear wheel; during the process of driving the two front wheels to rotate forward and driving the other rear wheel of the electric vehicle to rotate in the opposite direction, controlling the braking force output by the wheel-end braking device to the rear wheel to increase to a second braking force so that the rear wheel continues to remain locked.

[0017] 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 activated, controlling the second braking force to increase as the positive torque output by the motors corresponding to the two front wheels increases enables the locked rear wheel to remain locked, thereby preventing the electric vehicle from moving unexpectedly and improving the reliability and stability of the electric vehicle's U-turn.

[0018] In any possible implementation of the first aspect, the control method specifically includes: after the first moment, controlling the torque output of the motor corresponding to the rear wheel to decrease to zero at a first rate to unlock the rear wheel; after unlocking the rear wheel, controlling the torque output of the motor corresponding to the rear wheel to increase from zero at a second rate greater than the first rate to drive the rear wheel to rotate in the opposite direction. The above possible implementations can smoothly achieve the switching of the locking wheel, avoiding the jerking sensation during the locking wheel switching process and improving the user's driving experience.

[0019] In any possible implementation of the first aspect, the control method further includes: during the process of controlling the electric vehicle to make a U-turn, when the steering wheel's return angle is greater than a preset return angle, the electric vehicle's speed is greater than a preset speed, or the electric vehicle's brake pedal opening is greater than a preset brake opening, controlling the electric vehicle to stop making the U-turn. In the above possible implementations, when the steering wheel's return angle is greater than the preset return angle, it indicates that the user has returned the steering wheel to center and wishes to stop the electric vehicle's U-turn. Thus, in response to the driver's operation, the control method provided in this application embodiment controls the electric vehicle to stop making a U-turn, thereby improving the flexibility of the automatic U-turn function and ensuring the safety of the electric vehicle during the U-turn process.

[0020] In any possible implementation of the first aspect, the control method further includes: during the process of controlling the electric vehicle to make a U-turn, when the user operates the accelerator pedal, causing the opening of the accelerator pedal to decrease from greater than the preset accelerator opening to less than the preset accelerator opening, controlling the electric vehicle to stop making the U-turn. In the above possible implementations, when the accelerator pedal opening decreases to less than the preset accelerator opening, it indicates that the user has released the accelerator pedal, intending to stop the U-turn process of the electric vehicle. At this time, in response to the driver's operation, the control method provided in this application will control the vehicle to stop making the U-turn. For example, if the user finds an obstacle in the U-turn path during the U-turn process of the electric vehicle, the user can control the electric vehicle to stop making the U-turn by releasing the accelerator pedal, thereby avoiding an accident.

[0021] In any possible implementation of the first aspect, the control method further includes: during the process of controlling the electric vehicle to make a U-turn, controlling the vehicle speed to remain unchanged regardless of changes in the accelerator pedal opening when the accelerator pedal opening is greater than a preset accelerator pedal opening. In the above possible implementations, during the process of controlling the electric vehicle to make a U-turn, the vehicle speed remains at a constant rate or a preset rate, and the vehicle speed does not increase with the increase in the accelerator pedal opening. This ensures that the electric vehicle completes the U-turn at a stable speed, guaranteeing the stability and reliability of the electric vehicle during the U-turn process and improving the user's driving experience.

[0022] In a second aspect, a controller for an electric vehicle is provided, the controller being used to execute the control method described in the first aspect or any possible implementation thereof.

[0023] Thirdly, an electric vehicle is provided, the electric vehicle including a drive system, a braking system and a 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 perform the control methods described in the first aspect or any possible implementation of the first aspect.

[0024] Understandably, the beneficial effects that the controller and electric vehicle provided above can achieve can be referred to in the beneficial effects of the control method for automatic U-turn of electric vehicles provided above, and will not be repeated here. Attached Figure Description

[0025] Figure 1 is a schematic diagram of an electric vehicle making a U-turn in place;

[0026] Figure 2 is a schematic diagram of a leopard-style U-turn in an electric vehicle;

[0027] Figure 3 is a schematic diagram of an electric vehicle provided in an embodiment of this application;

[0028] Figure 4 is a schematic diagram of the architecture of a four-motor distributed drive electric vehicle provided in an embodiment of this application;

[0029] Figure 5 is a schematic diagram of the architecture of a three-motor distributed drive electric vehicle provided in an embodiment of this application;

[0030] Figure 6 is a schematic diagram of the architecture of a two-motor driven electric vehicle provided in an embodiment of this application;

[0031] Figure 7 is a schematic diagram of the automatic U-turn function activation provided in an embodiment of this application;

[0032] Figure 8 is a schematic diagram of an electric vehicle turning around according to an embodiment of this application;

[0033] Figure 9 is a signal timing diagram of a U-turn process of an electric vehicle provided in an embodiment of this application;

[0034] Figure 10 is a schematic diagram of another electric vehicle turning around process provided in an embodiment of this application;

[0035] Figure 11 is a schematic diagram of another electric vehicle turning around process provided in an embodiment of this application. Detailed Implementation

[0036] The following sections will discuss the fabrication and use of various embodiments in detail. However, it should be understood that many applicable inventive concepts provided in this application can be implemented in a variety of specific environments. The specific embodiments discussed are merely illustrative of specific ways of implementing and using this application and technology, and do not limit the scope of this application.

[0037] Before introducing the embodiments of this application, the application scenarios involved in this application will be described first.

[0038] When driving electric vehicles, situations often arise where U-turns are necessary. Conventional U-turn methods for electric vehicles result in a large turning radius and low efficiency. This is especially true when making U-turns on narrow roads or in complex road conditions, where users struggle to complete the maneuver due to limited lateral distance. Compared to conventional U-turn methods, techniques such as in-situ U-turns and "leopard turn" U-turns can significantly reduce the turning radius of electric vehicles during U-turns.

[0039] The following sections, in conjunction with Figures 1 and 2, introduce the techniques of U-turn on the spot and U-turn like a leopard.

[0040] As a first example, referring to Figure 1, which illustrates a schematic diagram of an electric vehicle making a U-turn on the spot. Taking the direction shown in Figure 1 as an example, the two wheels near the front of the vehicle are the two front wheels, and the two wheels near the rear are the two rear wheels. Based on their left-right positions, they can be categorized as left front wheel, right front wheel, left rear wheel, and right rear wheel. Specifically, taking the direction indicated by the arrow in Figure 1 as an example, when the electric vehicle needs to turn right to make a U-turn, the motors of the right front wheel and right rear wheel output reverse torque to drive the right front and right rear wheels in the opposite direction. The motors of the left front wheel and left rear wheel output forward torque to drive the left front and left rear wheels in the forward direction. In this way, the electric vehicle can turn around its own center during the U-turn, with a U-turn radius approximately half the axial length of the electric vehicle itself.

[0041] As a second example, referring to Figure 2, which illustrates a schematic diagram of an electric vehicle performing a U-turn. During the U-turn, the electric vehicle rotates from position 1 to position 2, and then from position 2 to position 3. Specifically, when the electric vehicle rotates to the right to make a U-turn, the front wheel motor outputs positive torque to drive the left and right front wheels in the forward direction, while the rear wheel motor outputs negative torque to drive the right rear wheel in the reverse direction. The braking system then locks the left rear wheel. In this way, the electric vehicle can turn with the left rear wheel as the center point during the U-turn, and the U-turn radius is approximately half the sum of the electric vehicle's axial length and body width.

[0042] In the first example above, the U-turn scheme has a small turning radius, but it has high requirements for the drive configuration of the electric vehicle; in the second example above, the leopard-style U-turn scheme has low requirements for the drive configuration of the electric vehicle, but its turning radius is relatively large and its turning efficiency is low.

[0043] Therefore, embodiments of this application provide a control method, controller, and electric vehicle for automatic U-turns of electric vehicles. The control method provided in this application detects the steering wheel rotation angle and the accelerator pedal opening, and activates the automatic U-turn function when the steering wheel rotation angle and the accelerator pedal opening meet certain conditions, thereby effectively reducing the difficulty of U-turns for electric vehicles and improving the user's driving experience.

[0044] The electric vehicle provided in this application will be described in detail below with reference to specific embodiments.

[0045] Referring to Figure 3, which is a schematic diagram of an electric vehicle according to an embodiment of this application, 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 supplies power to the drive system. The motor controller 20 controls the output torque of the motor 30 based on the electrical energy provided by the power battery 40. The vehicle controller 10 sends a torque signal to the motor controller 20, which receives the torque signal and controls the output torque of the motor 30 based on the torque signal, thereby driving the electric vehicle 01. Optionally, the electric vehicle 01 also includes a braking system (not shown in Figure 3), which provides braking force to the electric vehicle 01 when it is in a braking state.

[0046] The operating states of an electric vehicle include driving state and braking state. The functions of the vehicle controller 10 are explained below in conjunction with the operating states of electric vehicle 01.

[0047] When the electric vehicle 01 is in driving mode, the motor 30 in the drive system provides driving force to the electric vehicle 01. Specifically, when the electric vehicle 01 is in driving mode, the vehicle controller 10 calculates the torque demand of the electric vehicle 01 based on the accelerator pedal opening indicated by the accelerator pedal and outputs a torque signal to the motor controller 20. The motor controller 20 receives electrical energy from the power battery 40 and controls the motor 30 to output the torque value indicated by the torque signal.

[0048] When electric vehicle 01 is in a braking state, the drive system stops driving the wheels to rotate, and the braking system provides braking force to the wheels to reduce the speed of electric vehicle 01. During the braking state of electric vehicle 01, the motor 30 in electric vehicle 01 with energy recovery function can also provide braking force. Specifically, when electric vehicle 01 is in a braking state, the vehicle controller 10 receives a braking signal and sends an energy recovery command to the motor controller 20. The motor controller 20 responds to the energy recovery command by controlling the motor 30 to operate in a power generation state. The motor 30 converts the kinetic energy of the wheels of electric vehicle 01 into electrical energy and outputs reverse torque to the wheels of electric vehicle 01 to provide braking force. Here, the forward torque output of motor 30 means that the direction of the motor 30's output force is the same as the direction of the motor 30's rotational speed. The reverse torque output of motor 30 means that the direction of the motor 30's output force is opposite to the direction of the motor 30's rotational speed.

[0049] Optionally, the electric vehicle 01 mentioned above can be a four-motor distributed drive electric vehicle (as shown in Figure 4), a three-motor distributed drive electric vehicle (as shown in Figure 5), or a two-motor drive electric vehicle (as shown in Figure 6).

[0050] In one example, as shown in Figure 4, 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 controls motor 31 to drive wheel 41, motor controller 22 controls motor 32 to drive wheel 42, motor controller 23 controls motor 33 to drive wheel 43, and motor controller 24 controls motor 34 to drive wheel 44.

[0051] In another example, as shown in Figure 5, 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 controls motor 31 to drive wheel 41, motor controller 22 controls motor 32 to drive wheel 42, and motor controller 23 controls motor 33 to drive wheel 43 and wheel 44.

[0052] In another example, as shown in Figure 6, the electric vehicle 01 includes two motor controllers, two motors, and a braking system. The two motor controllers include motor controller 21 and motor controller 22. The two motors include motor 31 and motor 32. Motor controller 21 controls motor 31 to drive wheels 41 and 42, and motor controller 22 controls motor 32 to drive wheels 43 and 44. The braking system mainly includes a brake pedal (not shown in Figure 6), a brake controller 51, and four wheel-end braking devices 52. The brake controller 51 can generate a braking signal based on the opening degree of the brake pedal and, based on the indication of the braking signal, control one or more of the four wheel-end braking devices 52 to output braking force to the corresponding wheel to prevent wheel rotation or prevent the wheel's rotational tendency. Furthermore, during the braking process of the electric vehicle 01, the greater the opening degree of the brake pedal, the greater the braking force indicated by the brake signal, the greater the braking force output by the wheel-end braking devices 52, and the faster the speed of the electric vehicle 01 decreases.

[0053] Furthermore, the drive system, braking system, and vehicle controller 10 can communicate via a controller area network (CAN). For example, the vehicle controller 10 and the motor controller 20 in the drive system can communicate via a private CAN, the vehicle controller 10 and the brake controller 51 in the braking system can communicate via a public CAN, and the brake controller 51 and each wheel-end brake device 52 in the braking system can communicate via another private CAN. Alternatively, the vehicle controller 10 can also communicate separately with the motor controller 30 in the drive system and the brake controller 51 in the braking system via the same CAN.

[0054] Optionally, the vehicle controller 10 can also acquire a driving mode signal via CAN, which is used to indicate the current driving mode of the electric vehicle 01. For example, the driving mode may include one or more of the following: sport mode, comfort mode, and smart mode.

[0055] Optionally, the vehicle controller 10 can also acquire the electric vehicle gear position signal via CAN. The electric vehicle gear position signal is used to indicate the current gear position of the electric vehicle 01, such as forward gear, reverse gear, etc.

[0056] The electric vehicle control method provided in this application can be applied not only to the four-motor distributed drive electric vehicle shown in Figure 4, but also to the three-motor distributed drive electric vehicle shown in Figure 5, or the two-motor drive electric vehicle shown in Figure 6. It has low configuration requirements for electric vehicles and high practicality. The relevant steps of this electric vehicle control method can be executed by the electric vehicle controller of the electric vehicle. For example, the relevant functions of the electric vehicle controller can be implemented collaboratively by the vehicle controller and the motor controller in the drive system, or collaboratively by the vehicle controller, the motor controller in the drive system, and the brake controller in the braking system.

[0057] The architecture of the embodiments of this application has been described above. The automatic U-turn control method for electric vehicles provided by this application will be described below with reference to specific embodiments.

[0058] The control method in this 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, and controlling the electric vehicle to exit the automatic U-turn function.

[0059] The control method provided in this application will be described in detail below with reference to specific embodiments.

[0060] Control the automatic U-turn function when starting electric vehicles.

[0061] The control method provided in this 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 degree of the accelerator pedal of the electric vehicle being greater than a preset accelerator opening degree, activating the automatic U-turn function.

[0062] Users can select the automatic U-turn function in several ways. For example, the electric vehicle 01 can be equipped with a U-turn button for users to operate and select the automatic U-turn function. This U-turn button can be a physical button, which the user can press to activate the U-turn function of the electric vehicle 01. As shown in Figure 7, the U-turn button can also be a virtual button on the in-vehicle display screen or the central control display screen, which the user can select to activate the U-turn function of the electric vehicle 01. The vehicle controller or other controllers of the electric vehicle 01 can be used to detect the angle of the electric vehicle's steering wheel.

[0063] The preset angle and preset throttle opening are the trigger thresholds for the automatic U-turn function. For example, the preset angle can be 400 degrees and the preset throttle opening can be 20%.

[0064] In one embodiment, the control method provided in this 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 forward, detecting the steering wheel rotation angle of the electric vehicle. That is, before activating the automatic U-turn function, the control method provided in this application not only needs to detect the steering wheel rotation angle but also needs to detect the gear position of the electric vehicle to ensure that the electric vehicle is in forward gear.

[0065] In another embodiment, the control method provided in this application further includes: after the user selects the automatic U-turn function and before the steering wheel rotation angle is greater than a preset angle, setting the gear of the electric vehicle to forward gear. That is, for the control method provided in this application to activate the automatic U-turn function, the user also needs to set the gear of the electric vehicle to forward gear. In other words, after the user selects the U-turn function, the gear needs to be adjusted to forward gear, the steering wheel turned, and the accelerator pedal pressed to activate the automatic U-turn function.

[0066] Controlling an electric vehicle to turn around. Controlling an electric vehicle to turn around includes: locking one rear wheel of the electric vehicle, driving the two front wheels of the electric vehicle to rotate forward and driving the other rear wheel of the electric vehicle to rotate in the opposite direction, unlocking one rear wheel and locking the other rear wheel, and driving the two front wheels to rotate forward and driving the other rear wheel of the electric vehicle to rotate in the opposite direction.

[0067] In this embodiment of the application, the control method provided includes: locking one rear wheel of an electric vehicle, driving the two front wheels of the electric vehicle to rotate forward and driving the other rear wheel of the electric vehicle to rotate in the opposite direction to make the electric vehicle start to turn around; stopping the driving of the two front wheels and the other rear wheel at the first moment after the electric vehicle starts to turn around, and unlocking one rear wheel and locking the other rear wheel after the first moment, driving the two front wheels to rotate forward and driving the one rear wheel of the electric vehicle to rotate in the opposite direction to make the electric vehicle continue to turn around.

[0068] For ease of understanding, the method provided in this application embodiment will be illustrated below using the process of electric vehicle 01 making a U-turn as shown in Figure 8. In Figure 8, the arrow indicates a rightward rotation, meaning the user turns the steering wheel to the right to make electric vehicle 01 complete a clockwise U-turn.

[0069] In one example, as shown in Figure 8, before the electric vehicle 01 makes a U-turn, the electric vehicle 01 is in position 1. During the U-turn, 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 in the opposite direction to make the electric vehicle start to turn around, thereby causing the electric vehicle 01 to rotate from position 1 to position 2.

[0070] After the electric vehicle 01 reaches position 2, the two front wheels and the right rear wheel are stopped. Then, the left rear wheel of the electric vehicle 01 is unlocked and the right rear wheel, which is coaxial with the left rear wheel, is locked. After that, the two front wheels are driven to rotate forward and the left rear wheel is driven to rotate in the opposite direction, so that the electric vehicle 01 rotates from position 1 to position 3, completing the U-turn of the electric vehicle 01.

[0071] As can be seen from Figure 8, the lateral distance during the U-turn of the electric vehicle 01 is the axial length of the vehicle body.

[0072] Figure 8 is a schematic diagram of electric vehicle 01 turning right to complete a U-turn. The process of electric vehicle 01 turning left to complete a U-turn is similar and will not be described in detail here.

[0073] The control method provided in this 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. Different methods are provided in this application to lock the rear wheels of the electric vehicle 01.

[0074] In one embodiment, the control method provided in this application locks a rear wheel by controlling the rotational speed of a rear-drive motor corresponding to a rear wheel to zero, thereby reducing the wheel speed of that rear wheel to zero. Specifically, the electric vehicle controller can output a rotational speed signal to the motor controller of the rear-drive motor corresponding to the rear wheel; the motor controller, based on the rotational speed signal, controls the rotational speed of the rear-drive motor corresponding to the rear wheel to zero, so that the rear wheel stops rotating. The rotational speed signal is used to indicate that the motor controller is operating in rotational speed mode and controls the rotational speed of the rear-drive motor to zero. Optionally, when the motor controller is operating in rotational speed mode, the motor controller can sample the resolver speed of the rear-drive motor and perform closed-loop control of the rear-drive motor based on the sampled value, thereby controlling the rotational speed of the rear-drive motor to zero. Taking the electric vehicle 01 shown in Figure 4 as an example, and referring to Figure 8, during the process of electric vehicle 01 moving from position 1 to position 2, motor controller 23 controls the speed of motor 33 to zero to lock the left rear wheel 43. During the process of electric vehicle 01 moving from position 2 to position 3, motor controller 24 controls the speed of motor 34 to zero to lock the right rear wheel 44. That is, during the process of electric vehicle 01 moving from position 1 to position 2, motor 33 operates in speed mode, with zero speed as the control target, thereby locking the left rear wheel 43, while motor 34 operates in torque mode, outputting reverse torque to drive the right rear wheel 44 to rotate in the opposite direction. During the process of electric vehicle 01 moving from position 2 to position 3, motor 34 operates in speed mode, with zero speed as the control target, thereby locking the right rear wheel 44, while motor 33 operates in torque mode, outputting reverse torque to drive the left rear wheel 43 to rotate in the opposite direction.

[0075] In another embodiment, the control method provided in this application locks a rear wheel by controlling the wheel-end braking device corresponding to a rear wheel to output braking force to that rear wheel, thereby reducing the wheel speed of that rear wheel to zero. Specifically, taking the electric vehicle shown in Figure 6 as an example, the vehicle controller 10 can output a braking signal to the brake controller 51. The brake controller 51 can control the wheel-end braking device 52 corresponding to the left rear wheel 43 to output braking force according to the indication of the braking signal. The wheel-end braking device 52 can gradually increase the output braking force until it exceeds the braking force threshold and locks the left rear wheel 43, causing the left rear wheel 43 to stop rotating. Taking the electric vehicle 01 shown in Figure 4 as an example, combined with the process of the electric vehicle 01 turning right as shown in Figure 8, during the process of the electric vehicle 01 moving from position 1 to position 2, the wheel-end braking device 52 outputs braking force to the left rear wheel 43 to lock the left rear wheel 43. During the process of the electric vehicle 01 moving from position 2 to position 3, the wheel-end braking device 52 outputs braking force to the right rear wheel 44 to lock the right rear wheel 44.

[0076] In one embodiment, the control method provided in this application specifically includes: after activating the automatic U-turn function, first locking one rear wheel, and after locking the one rear wheel, driving the two front wheels to rotate in the forward direction and driving the other rear wheel to rotate in the reverse direction.

[0077] The control method provided in this application locks one rear wheel before driving the electric vehicle 01 to rotate. This ensures that the electric vehicle 01 rotates around that rear wheel, preventing unexpected movement of the electric vehicle 01 and thus improving the safety of the electric vehicle 01 during U-turns and the driver's driving experience. For example, as shown in Figure 8, when the electric vehicle 01 is making a right U-turn, after activating the automatic U-turn function, the left rear wheel is locked first. After locking the left rear wheel, the two front wheels are driven to rotate forward, and the right rear wheel is driven to rotate in the opposite direction, so that the electric vehicle 01 moves from position 1 to position 2.

[0078] In one embodiment, the control method provided in this application specifically includes: after a first moment, first unlocking 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 in the forward direction and driving one rear wheel of the electric vehicle to rotate in the reverse direction.

[0079] As shown in Figure 8, during the process of electric vehicle 01 making a right turn, at the first moment when electric vehicle 01 moves from position 1 to position 2, it stops driving the two front wheels and the other rear wheel. After the first moment, it first unlocks the left rear wheel and then locks the right rear wheel. Then it drives the two front wheels of the electric vehicle to rotate in the forward direction and drives one rear wheel of the electric vehicle to rotate in the reverse direction. This ensures that the two front wheels do not rotate during the switching process, thus preventing electric vehicle 01 from moving unexpectedly.

[0080] In one embodiment, the control method provided in this application specifically includes: after activating 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 braking force output by the wheel-end braking device to the rear wheel to increase to a second braking force during the forward rotation of the two front wheels to keep the rear wheel locked.

[0081] Referring to the process of electric vehicle 01 making a right turn as shown in Figure 8, after the automatic turn function is activated, before driving the two front wheels to rotate forward and the right rear wheel of the electric vehicle to rotate in the opposite direction, the drive motors corresponding to the two front wheels have not yet output torque. First, the wheel-end braking device corresponding to the left rear wheel is controlled to output a small first braking force to lock the left rear wheel. During the process of driving the two front wheels to rotate forward and driving the right rear wheel of the electric vehicle to rotate in the opposite direction, the braking force output by the wheel-end braking device to the left rear wheel is increased to a second braking force to keep the left rear wheel locked.

[0082] In one embodiment, the control method provided in this application specifically includes: during the process of driving the two front wheels of an electric vehicle to rotate in the forward direction, controlling the second braking force to increase as the forward torque output by the motors corresponding to the two front wheels increases.

[0083] As shown in Figure 8, during the process of electric vehicle 01 making a right turn, after the automatic turn function is activated, as electric vehicle 01 moves from position 1 to position 2, the second braking force is controlled to increase as the positive torque output by the motors corresponding to the two front wheels increases to ensure that the left rear wheel can remain locked, thereby avoiding unexpected movement of electric vehicle 01 and improving the reliability and stability of electric vehicle 01's turn.

[0084] In one embodiment, the control method provided in this application specifically includes: after a first moment, controlling the torque output of 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 of the motor corresponding to the rear wheel to increase from zero at a second rate greater than the first rate to drive the rear wheel to rotate in the opposite direction.

[0085] Referring to the process of electric vehicle 01 making a right turn as shown in Figure 8, for the method of locking the wheels by controlling the zero speed 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 speed to unlock the left rear wheel 43 and lock the right rear wheel 44. Then, the motor 33 corresponding to the left rear wheel 43 is controlled to increase at a second speed greater than the first speed to drive one rear wheel to rotate in the opposite direction so that electric vehicle 01 can continue to turn around. This ensures that the motor 33 can achieve the transition from zero speed mode to torque mode at a relatively smooth speed, avoiding the jerking sensation during the wheel locking process and improving the user's driving experience.

[0086] In one embodiment, the control method provided in this application further includes: during the process of controlling the electric vehicle to make a U-turn, controlling the vehicle speed to remain unchanged regardless of the accelerator pedal opening when the accelerator pedal opening is greater than a preset accelerator pedal opening. That is, during the process of controlling the electric vehicle to make a U-turn, the vehicle speed remains constant or at a preset speed, and the vehicle speed does not increase with the increase of the accelerator pedal opening, thereby ensuring the stability and reliability of the electric vehicle 01 during the U-turn process.

[0087] In one embodiment, the control method provided in this application further includes: during the process of controlling the wheel-end braking device corresponding to a rear wheel to output braking force to lock a rear wheel, controlling the output braking force of the wheel-end braking device corresponding to a rear wheel to decrease as the adhesion coefficient between the rear wheel and the road surface decreases.

[0088] Referring to the process of electric vehicle 01 making a right turn as shown in Figure 8, during the process of controlling the left rear wheel's wheel-end braking device to output braking force to lock the left rear wheel, when the coefficient of friction between the left rear wheel and the road surface decreases, the braking force output by the wheel-end braking device of the left rear wheel can be reduced accordingly. This is to avoid excessive braking force causing the left rear wheel to lose friction with the road surface, thereby preventing the left rear wheel from slipping. Therefore, the control method provided in this application embodiment can set different braking force parameters according to different coefficients of friction during the wheel locking process, thereby applying different braking forces according to different braking force parameters, thus improving the user's driving safety.

[0089] In another possible embodiment, during the process of the front drive motor outputting positive torque to drive the two front wheels to rotate in the forward direction, the torque output by the front drive motor is controlled to increase as the coefficient of adhesion between the two front wheels and the road surface increases; during the process of the other rear drive motor outputting reverse torque to drive the other rear wheel to rotate in the reverse direction, the torque output by the other rear drive motor is controlled to increase as the coefficient of adhesion between the other rear wheel and the road surface increases.

[0090] Referring to the process of electric vehicle 01 making a right turn as shown in Figure 8, during the forward rotation of the two front wheels (left and right front wheels) driven by the front drive motor outputting positive torque, a higher coefficient of adhesion between the two front wheels and the road surface indicates greater traction that the two front wheels can utilize. Therefore, a larger driving force can be output to ensure the normal rotation of the two front wheels on the road surface. Similarly, during the reverse rotation of the right rear wheel driven by the rear drive motor outputting reverse torque, a higher coefficient of adhesion between the right rear wheel and the road surface indicates greater traction that the right rear wheel can utilize. Therefore, a larger reverse torque can be output to ensure the right rear wheel can rotate normally in the reverse direction on the road surface.

[0091] Control the electric vehicle to disengage from the automatic U-turn function.

[0092] In one embodiment, the control method provided in this application includes: stopping the driving of the two front wheels and one rear wheel at a second moment after the electric vehicle continues to make a U-turn, and unlocking the other rear wheel after the second moment to cause the electric vehicle to exit the automatic U-turn function.

[0093] Referring to Figure 8, during the process of electric vehicle 01 making a right turn, the electric vehicle completes the turn at the second moment after reaching position 3. The control method provided in this embodiment can control the electric vehicle to exit the automatic turn function. In controlling the electric vehicle to exit the automatic turn function, the two front wheels and the left rear wheel are stopped first, and then the right rear wheel is unlocked. This allows the vehicle to stop stably and exit the turn, thereby improving the safety of electric vehicle 01 during the turn and enhancing the user's driving experience. If the right rear wheel is unlocked before the two front wheels and the left rear wheel have stopped, the electric vehicle 01 will lurch forward under the drive of the two front wheels and the left rear wheel, affecting the user's driving experience.

[0094] In one embodiment, the control method provided in this application includes: during the process of controlling an electric vehicle to make a U-turn, when the steering wheel's return angle is greater than a preset return angle, controlling the electric vehicle to stop making the U-turn.

[0095] When the steering wheel's return angle is greater than the preset return angle, it indicates that the user has returned the steering wheel to center and intends 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 embodiment will control the electric vehicle 01 to stop the U-turn.

[0096] In another embodiment, the control method provided in this application further includes: during the process of controlling the electric vehicle to make a U-turn, when the speed of the electric vehicle is greater than a preset speed, controlling the electric vehicle to stop making the U-turn.

[0097] When the speed of electric vehicle 01 exceeds a preset speed, it indicates that the speed of electric vehicle 01 is too high during the automatic U-turn. Making a U-turn at excessive speed can easily cause the vehicle's posture to become uncontrollable, leading to danger. Furthermore, making a U-turn at excessive speed can also cause panic for the driver. Therefore, the control method provided in this application embodiment will control the electric vehicle to stop making a U-turn when its speed exceeds a preset speed to improve safety and enhance the user's sense of security. For example, the preset speed could be 10 km / h; if the speed exceeds this preset speed during the U-turn, the electric vehicle will be controlled to stop making the U-turn.

[0098] In another embodiment, the control method provided in this application further includes: during the process of controlling the electric vehicle to turn around, when the user operates the accelerator pedal to reduce the opening of the accelerator pedal from greater than a preset accelerator opening to less than a preset accelerator opening, the vehicle is controlled to stop turning around.

[0099] For example, when the accelerator pedal opening decreases to less than the preset accelerator pedal opening, it indicates that the user has released the accelerator pedal, intending 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 the U-turn. For example, if the user finds an obstacle in the U-turn path during the U-turn process of the electric vehicle 01, the user can control the electric vehicle to stop the U-turn by releasing the accelerator pedal to avoid an accident.

[0100] In another embodiment, the control method provided in this application further includes: during 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 the driving of the four wheels of the electric vehicle 01.

[0101] For example, when the brake pedal opening is greater than the preset brake opening, it indicates that the user has pressed the brake pedal, intending to stop the U-turn process of the electric vehicle 01. In this case, to respond to the driver's operation, the control method provided in this application embodiment will control the electric vehicle to stop the U-turn. That is, in an emergency, the user can press the brake pedal to control the electric vehicle 01 to stop the U-turn.

[0102] Based on the above operations, when the controller of the electric vehicle detects that any one or more of the following conditions are met: a change in the opening degree of the brake pedal, a change in the steering wheel angle, or a change in the opening degree of the accelerator pedal, the control method provided in this application embodiment 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.

[0103] The process of controlling an electric vehicle to make a U-turn to the right is described in detail below with reference to Figure 9 and specific embodiments.

[0104] The period from before time t1 to time t1 is the startup phase. 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 activated.

[0105] The period from time t1 to t5 is the turning phase. At time t1, the automatic U-turn function is activated. The braking system first outputs braking force to the left rear wheel to lock it. 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 begin turning. While the drive motors corresponding to the two front wheels are outputting torque to drive the electric vehicle to begin turning, the braking system continuously outputs braking force to the left rear wheel to keep it locked. It should be noted that after the automatic U-turn function is activated, the wheel-end braking device of the left rear wheel first outputs braking force to lock the left rear wheel, and then controls the electric vehicle 01 to begin turning. This ensures that the left rear wheel is already locked when the drive motors corresponding to the two front wheels begin to output torque, preventing the electric vehicle 01 from moving forward and deviating from its original position if the rear wheel is not locked.

[0106] Furthermore, after the automatic U-turn function is activated, from time t1 to t2, the wheel-end braking device corresponding to the left rear wheel first outputs a first braking force to lock the left rear wheel. After time t2, the braking force output by the wheel-end braking device to the left rear wheel is increased to a second braking force to keep the left rear wheel locked. This is because from time t1 to t2, the drive motors corresponding to the two front wheels have not yet output torque, so the wheel-end braking device corresponding to the left rear wheel only needs to output a small first braking force. However, 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 braking device to the left rear wheel needs to be increased to a second braking force to keep the left rear wheel locked.

[0107] From time t2 to time t3, the torque output by the drive motors corresponding to the two front wheels continuously increases, meaning that the period from time t2 to time t3 is the process of establishing drive torque. From time t3 to time t4, the torque output by the drive motors corresponding to the two front wheels is relatively stable, meaning that the time period from time t3 to time t4 is the process of the electric vehicle making a stable U-turn.

[0108] At time t4, i.e., the first moment, electric vehicle 01 completes the first stage of turning. Referring to Figure 8, this means that electric vehicle 01 has turned to position 2 at time t4. The turning angle of electric vehicle 01 can be any angle between 0° and 180°. For example, this turning angle can be 30°, 45°, 60°, 90°, 120°, 135°, or 150°. This turning angle is related to the road conditions when electric vehicle 01 makes a U-turn. For example, this turning angle can be determined based on the road width and road conditions such as obstacles when electric vehicle 01 makes a U-turn, or it can be a turning angle preset by the user.

[0109] The transition period is from time t4 to time t7. During this transition period, the locked wheel will be switched from the left rear wheel to the right rear wheel.

[0110] From time t4 to time t5, the torque output of the drive motors corresponding to the two front wheels is gradually reduced to zero; from time t5 to time t6, the braking force output of the wheel-end brake device of the left rear wheel is gradually reduced to zero so that the left rear wheel is unlocked; from time t6 to time t7, the braking force output of the wheel-end brake device of the right rear wheel is increased to lock the right rear wheel. At this time, the locking wheel of electric vehicle 01 is switched from the left rear wheel to the right rear wheel.

[0111] During the switching phase, the control method provided in this application first controls the torque output of the drive motors corresponding to the two front wheels to gradually decrease to zero, then controls the braking force output of the wheel-end braking device of the left rear wheel to gradually decrease to zero so that the left rear wheel is unlocked, and finally controls the braking force output of the wheel-end braking device of the right rear wheel to increase so as to lock the right rear wheel. This ensures that the two front wheels do not rotate during the switching process, preventing the electric vehicle 01 from undergoing unexpected movement.

[0112] The period from time t7 to time t8 is the continued steering phase. 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 steer with the right rear wheel as the center.

[0113] The period from time t8 to time t10 is the exit phase.

[0114] At time t8, electric vehicle 01 completes the U-turn, i.e., the second time. Referring to Figure 8, this means that electric vehicle 01 has rotated to position 3 at time t8. At this point, the user releases the accelerator pedal until the pedal opening is less than the preset pedal opening. From time t8 to time t9, the torque output of the drive motors corresponding to the two front wheels begins to decrease to zero. After the torque output of 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 reduced to zero to unlock the left rear wheel, and electric vehicle 01 exits the U-turn function. During the process of electric vehicle 01 exiting the U-turn function, it is also necessary to reduce the braking force of the left rear wheel to zero to unlock the left rear wheel only after the torque output of the drive motors corresponding to the two front wheels begins to decrease to zero, thereby preventing unintended movement of electric vehicle 01.

[0115] Figures 10 and 11 illustrate two other methods for achieving on-the-spot U-turns for electric vehicles.

[0116] In the example provided in Figure 10, before the electric vehicle 01 makes a U-turn, it is in position 1. During the U-turn, the right front wheel of the electric vehicle 01 is locked, the rear drive motor outputs reverse torque to drive the left and right rear wheels to rotate in the opposite direction, and the front drive motor outputs forward torque to drive the left front wheel to rotate in the forward direction. With the rotation of the left front wheel, left rear wheel, and right rear wheel, the electric vehicle 01 rotates from position 1 to position 2, a rotation of 90°. After the electric vehicle 01 reaches position 2, its drive system first stops driving all four wheels, unlocks the right front wheel, and locks the left front wheel, which is coaxial with the right front wheel. 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 forward torque to drive the right front wheel to rotate in the forward direction. The electric vehicle 01 rotates from position 2 to position 3 by rotating its right front wheel, left rear wheel, and right rear wheel, completing a 90° turn. At this time, the lateral distance of the electric vehicle 01 during the turn is its axial length. The control method for the electric vehicle 01 during the turn, as shown in Figure 10, has been described previously and will not be repeated here.

[0117] In the example provided in Figure 11, before the electric vehicle 01 makes a U-turn, it is in position 1, i.e., its front is facing upwards as shown in Figure 11. During the U-turn, 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 in the forward direction, and the rear drive motor of the right rear wheel outputs negative torque to drive the right rear wheel to rotate in the reverse direction. With the rotation of the left front wheel, right front wheel, and 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 all four wheels of the electric vehicle 01, unlocks the left rear wheel and locks the left front wheel on the same side as the left rear wheel. Then, the front drive motor of the right front wheel outputs positive torque to drive the right front wheel to rotate in the forward direction, and the rear drive motors of the two rear wheels output negative torque to drive the two rear wheels to rotate in the reverse direction. The electric vehicle 01 rotates from position 2 to position 3 by rotating its right front wheel, left rear wheel, and right rear wheel, completing a 90° turn. At this time, the lateral distance of the electric vehicle 01 during the turn is its axial length. The control method for the electric vehicle 01 during the turn, as shown in Figure 11, has been described previously and will not be repeated here.

[0118] In another embodiment of this application, an electric vehicle controller for an electric vehicle is also provided, which is used to control the electric vehicle to achieve an automatic U-turn function.

[0119] In another embodiment of this application, an electric vehicle is also provided, which includes a drive system, a braking system, and a controller provided in the above embodiments. 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.

[0120] It is understood that all relevant content of each step involved in the above method embodiments can be referenced in the embodiments of the controller and the embodiments of the electric vehicle, and will not be repeated here.

[0121] Finally, it should be noted that 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 within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A 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, the rotation angle of the steering wheel of the electric vehicle is detected; After the steering wheel is rotated at an angle greater than a preset angle, the automatic U-turn function is activated in response to the accelerator pedal opening of the electric vehicle being greater than a preset accelerator opening.

2. The control method according to claim 1, characterized in that, The control method further includes: After the user selects to make a U-turn but before the steering wheel rotation angle is greater than a preset angle, the gear of the electric vehicle is set to forward gear.

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

4. The control method according to claim 1 or 2, characterized in that, The control method further includes: After the automatic U-turn function is activated, one rear wheel of the electric vehicle is locked, the two front wheels of the electric vehicle are driven to rotate in the forward direction, and the other rear wheel of the electric vehicle is driven to rotate in the reverse direction so that the electric vehicle begins to turn around. The electric vehicle stops driving the two front wheels and the other rear wheel at the first moment after it begins to turn around. After the first moment, the other rear wheel is unlocked and the other rear wheel is locked. The two front wheels are driven to rotate forward and the other rear wheel is driven to rotate in the opposite direction so that the electric vehicle can continue to turn around.

5. The control method according to claim 4, characterized in that, The control method further includes: At a second moment after the electric vehicle continues to turn around, drive the two front wheels and the one rear wheel, and unlock the other rear wheel after the second moment to deactivate the automatic U-turn function.

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

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

8. The control method according to claim 6, characterized in that, The control method specifically includes: After activating the automatic U-turn function, the wheel-end braking device corresponding to the rear wheel is first controlled to output a first braking force to lock the rear wheel. Then, during the process of driving the two front wheels to rotate in the forward direction, the braking force output by the wheel-end braking device to the rear wheel is increased to a second braking force to keep the rear wheel locked.

9. The control method according to claim 8, characterized in that, The control method further includes: 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, the torque output by the motor corresponding to the rear wheel is reduced to zero at a first rate to unlock the rear wheel; After unlocking one of the rear wheels, the torque output of the motor corresponding to the one rear wheel is increased 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 includes: During the process of controlling the electric vehicle to make a U-turn, if the steering wheel's return angle is greater than a preset return angle, the electric vehicle's speed is greater than a preset speed, or the electric vehicle's brake pedal opening is greater than a preset braking opening, the electric vehicle is controlled to stop making the U-turn.

12. The control method according to claim 1, characterized in that, The control method further includes: During the process of controlling the electric vehicle to turn around, when the user operates the accelerator pedal to reduce the opening of the accelerator pedal 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 includes: During the process of controlling the electric vehicle to turn around, the speed of the electric vehicle is controlled to remain unchanged regardless of the change in the opening of the accelerator pedal when the opening of the accelerator pedal is greater than the preset accelerator pedal opening.

14. A controller for an electric vehicle, characterized in that, The controller is used to perform the control method as described in 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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