Control method of electric vehicle, controller and electric vehicle

Abstract

The invention provides a control method of an electric vehicle, a controller and the electric vehicle, and is applied to the technical field of electric vehicles. According to the control method, by actively adjusting the steering angle of the wheels, the running stability of the electric vehicle on the split road surface is improved. In the straight driving process of the electric vehicle on the split road surface, before the steering angle of a steering wheel changes, by actively controlling steering of wheels of the electric vehicle, under the condition that a driver does not operate the rotating direction and angle of the steering wheel, yawing moment generated due to large road holding force difference is actively balanced, yawing of the electric vehicle is restrained, and the driving stability of the electric vehicle is improved. The running stability of the electric vehicle on the split road surface is improved, and the driving experience is improved. After the electric vehicle is driven away from the opposite road surface and before the steering angle of the steering wheel is changed, the wheels of the electric vehicle are actively controlled to return to be right, the situation that the wheels of the electric vehicle still keep steering, and consequently the electric vehicle yaws is avoided, and the electric vehicle returns to the normal driving state.

Description

Technical Field

[0001] This application relates to the field of electric vehicle technology, and more particularly to a control method, controller, and electric vehicle for an electric vehicle. Background Technology

[0002] When electric vehicles travel on split-level roads, the significant difference in traction between the left and right wheels can cause them to veer off course. This requires the driver to constantly turn the steering wheel to correct the vehicle's trajectory, a cumbersome process that is extremely difficult to control accurately, resulting in low stability when driving on split-level roads. Summary of the Invention

[0003] This application provides a control method, controller, and electric vehicle for an electric vehicle, which improves the stability of the electric vehicle when driving on a split road by actively adjusting the steering angle of the wheels.

[0004] In a first aspect, embodiments of this application provide a control method for an electric vehicle, comprising the following steps.

[0005] When an electric vehicle is traveling on a uniform road surface, the steering of the wheels is controlled based on the direction and angle of the steering wheel rotation. Specifically, the difference in the coefficient of friction between the two wheels on the same axle and the road surface is less than a preset value during this process.

[0006] When an electric vehicle is traveling straight on a split-level road, the steering of the wheels is actively controlled before the steering wheel angle changes. Specifically, the difference in the coefficient of friction between the two wheels on the same axle and the road surface is greater than a preset value during this travel.

[0007] And after the electric vehicle leaves the opposite road surface, before the steering wheel angle changes, actively control the electric vehicle's wheels to return to center.

[0008] In this embodiment, while the electric vehicle is traveling on a uniform road surface, the steering of the electric vehicle's wheels is controlled according to the direction and angle of the steering wheel rotation, allowing the driver to precisely control the vehicle's trajectory by operating the steering wheel. When the electric vehicle is traveling straight on a split road surface, before the steering wheel angle changes, the active control of the wheel steering allows the lateral force of the actively steered wheels to actively balance the yaw moment caused by the significant difference in grip, suppressing yaw and improving the vehicle's stability on split road surfaces. This reduces the driver's operational complexity and enhances the driving experience. After the electric vehicle leaves the split road surface, before the steering wheel angle changes, the wheels are actively controlled to return to center, preventing the wheels from remaining steered on the split road surface and causing yaw, thus returning the electric vehicle to a normal driving state.

[0009] In one embodiment of the first aspect, the control method further includes: during the process of the electric vehicle traveling straight on the split road surface, before the steering angle of the steering wheel changes, actively controlling the sum of the torques output by the drive system of the electric vehicle to the two right wheels to be equal to the sum of the torques output to the two left wheels; after the electric vehicle leaves the split road surface, before the steering angle of the steering wheel changes, actively controlling the sum of the torques output by the drive system of the electric vehicle to the two right wheels to be equal to the sum of the torques output to the two left wheels.

[0010] In this embodiment, while the electric vehicle is traveling on a split-level road, the sum of the torques output to the two right wheels is actively controlled to be different from the torques output to the two left wheels. This actively adjusts the torque output to the high-touch and low-touch wheels of the drive system, fully utilizing the traction of both sides and preventing wheel slippage, thus improving the acceleration and deceleration performance of the electric vehicle. After the electric vehicle leaves the split-level road, before the steering wheel angle changes, the sum of the torques output to the two right wheels of the drive system is actively controlled to be equal to the sum of the torques output to the two left wheels, maintaining the electric vehicle's straight-line travel.

[0011] In one embodiment of the first aspect, the control method specifically includes: the coefficient of adhesion of the two right wheels of the electric vehicle to the opposing road surface is greater than the coefficient of adhesion of the two left wheels; and during the process of the electric vehicle traveling straight on the opposing road surface, before the steering angle of the steering wheel changes, actively controlling the steering angle of at least one right wheel of the electric vehicle to be greater than the steering angle of the left wheel that is coaxial with at least one right wheel.

[0012] In this embodiment, when the coefficient of adhesion of the two right wheels of the electric vehicle to the opposing road surface is greater than that to the two left wheels, the grip provided by the opposing road surface to the two right wheels is greater than that provided to the two left wheels. The grip is the resultant force of the longitudinal force in the forward or backward direction of the electric vehicle and the lateral force perpendicular to the forward or backward direction of the electric vehicle. By actively controlling the steering angle of at least one right wheel of the electric vehicle to be greater than the steering angle of the left wheel coaxial with at least one right wheel, the lateral force of at least one wheel on the high-attachment side is actively adjusted to be larger and the lateral force of the wheel coaxial with the low-attachment side is smaller, so that the longitudinal force of the wheel on the high-attachment side is close to the same as that of the wheel on the low-attachment side, and the electric vehicle can still maintain straight-line driving on the opposing road surface.

[0013] In this embodiment, taking the case where the adhesion coefficient of the two right wheels to the open road surface is greater than that to the two left wheels as an example, and the case where the adhesion coefficient of the two right wheels to the open road surface is less than that to the two left wheels, the steering angle of at least one right wheel of the actively controlled electric vehicle is less than the steering angle of the left wheel that is coaxial with at least one right wheel. This is completely similar and will not be described in detail here.

[0014] In one embodiment of the first aspect, the control method specifically includes: when the electric vehicle is traveling straight on a split road, before the steering angle of the steering wheel changes, when the opening of the accelerator pedal is greater than a preset accelerator pedal opening, actively controlling the two front wheels of the electric vehicle to turn to the right and the steering angle of the two rear wheels to be zero.

[0015] In this embodiment, when the electric vehicle is traveling straight on a split-road surface, the system automatically detects the user's intention to accelerate the vehicle by detecting that the accelerator pedal opening is greater than a preset accelerator pedal opening. When the accelerator pedal opening is greater than the preset accelerator pedal opening, the system actively controls the two front wheels of the electric vehicle to turn to the right and the two rear wheels to turn at zero angle. This ensures that the lateral force of the turned wheels provides a counteracting yaw moment that is generated due to the significant difference in grip caused by the electric vehicle traveling on a split-road surface, thereby suppressing the yaw of the electric vehicle.

[0016] In one embodiment of the first aspect, the control method specifically includes: when the electric vehicle is traveling straight on a split road, before the steering angle of the steering wheel changes, when the opening of the brake pedal is greater than a preset brake pedal opening, actively controlling the two front wheels of the electric vehicle to turn to the left and the steering angle of the two rear wheels to be zero.

[0017] In this embodiment, when the electric vehicle is traveling straight on a split-road surface, the system automatically detects the user's intention to brake by detecting that the brake pedal opening is greater than a preset brake pedal opening. When the brake pedal opening is greater than the preset brake pedal opening, the system actively controls the two front wheels of the electric vehicle to turn to the left and the two rear wheels to turn at zero angle. This ensures that the lateral force of the turned wheels provides a counteracting yaw moment caused by the significant difference in grip between the electric vehicle and the road surface, thereby suppressing the yaw of the electric vehicle.

[0018] In one embodiment of the first aspect, the control method specifically includes: when the electric vehicle is traveling straight on a split road, before the steering angle of the steering wheel changes, when the opening of the accelerator pedal is greater than a preset accelerator pedal opening, actively controlling the two front wheels of the electric vehicle to turn to the right and the two rear wheels to turn to the left.

[0019] In this embodiment, when the electric vehicle is traveling straight on a split road, if the opening of the accelerator pedal is greater than the preset accelerator pedal opening, the two front wheels of the electric vehicle are actively controlled to turn right and the two rear wheels to turn left. This allows the lateral forces of the two front wheels and the two rear wheels to work together to provide a counter-clockwise yaw moment that counteracts the counter-clockwise yaw moment caused by the large difference in grip force when the electric vehicle is traveling on a split road. This reduces the sideslip angle of the electric vehicle and suppresses the yaw of the electric vehicle.

[0020] In one embodiment of the first aspect, the control method specifically includes: when the electric vehicle is traveling straight on a split road, before the steering angle of the steering wheel changes, when the opening of the brake pedal is greater than a preset brake pedal opening, actively controlling the two front wheels of the electric vehicle to turn to the left and the two rear wheels to turn to the right.

[0021] In this embodiment, when the electric vehicle is traveling straight on a split road, if the brake pedal opening is greater than the preset brake pedal opening, the two front wheels of the electric vehicle are actively controlled to turn left and the two rear wheels to turn right. This causes the lateral forces of the front and rear wheels to work together to provide a yaw moment that counteracts the clockwise yaw moment caused by the large difference in grip force when the electric vehicle is traveling on a split road. This reduces the sideslip angle of the electric vehicle and suppresses the yaw of the electric vehicle.

[0022] In one embodiment of the first aspect, the control method specifically includes: during the process of the electric vehicle traveling in a straight line on a split road, before the steering angle of the steering wheel changes, actively controlling the two right wheels of the electric vehicle to turn in different directions and the two left wheels to turn at zero angles.

[0023] In this embodiment, during the straight-line travel of the electric vehicle on a split-road surface, before the steering angle of the steering wheel changes, the two right wheels of the electric vehicle are actively controlled to steer in different directions. This ensures that after active steering, the lateral force of the high-tether side wheel provides a yaw moment to counteract the yaw moment caused by the significant difference in grip, while the lateral forces of the two high-tether side wheels are balanced. That is, the lateral forces of the right front wheel and the right rear wheel are balanced, thereby reducing the sideslip angle of the electric vehicle's center of gravity and improving the stability of the electric vehicle on the split-road surface. Furthermore, by actively controlling the steering angle of the two left wheels to zero, the low-tether side wheel is only used to provide longitudinal force, enabling the electric vehicle to achieve maximum longitudinal acceleration or deceleration. This allows the electric vehicle to maintain straight-line travel with maximum longitudinal acceleration or deceleration on the split-road surface.

[0024] In one embodiment of the first aspect, the control method specifically includes: when the electric vehicle is traveling straight on a split road, before the steering angle of the steering wheel changes, when the opening of the accelerator pedal is greater than a preset accelerator pedal opening, actively controlling the right front wheel to turn right and the right rear wheel to turn left.

[0025] In this embodiment, when the electric vehicle is traveling straight on a split-road surface, before the steering angle of the steering wheel changes, if the opening of the accelerator pedal is greater than the preset accelerator pedal opening, the right front wheel is actively controlled to turn right and the right rear wheel to turn left. This allows the lateral force of the steering wheels to provide a counter-clockwise yaw moment that counteracts the counter-clockwise yaw moment caused by the large difference in grip between the electric vehicle and the split-road surface. This suppresses the yaw of the electric vehicle, and the lateral forces of the right front wheel and the right rear wheel can be balanced, thereby reducing the sideslip angle of the electric vehicle's center of gravity and further improving the stability of the electric vehicle when traveling on a split-road surface.

[0026] In one embodiment of the first aspect, the control method specifically includes: when the electric vehicle is traveling straight on a split road, before the steering angle of the steering wheel changes, when the opening of the brake pedal is greater than a preset brake pedal opening, actively controlling the right front wheel to turn to the left and the right rear wheel to turn to the right.

[0027] In this embodiment, when the electric vehicle is traveling straight on a split-road surface, before the steering angle of the steering wheel changes, if the opening of the brake pedal is greater than the preset brake pedal opening, the right front wheel is actively controlled to turn left and the right rear wheel to turn right. This allows the lateral force of the steering wheels to provide a counteracting yaw moment caused by the significant difference in grip between the electric vehicle and the split-road surface, thereby suppressing the yaw of the electric vehicle. Furthermore, the lateral forces of the right front wheel and the right rear wheel can be balanced, reducing the sideslip angle of the electric vehicle's center of gravity and further improving the stability of the electric vehicle when traveling on a split-road surface.

[0028] In one embodiment of the first aspect, the control method specifically includes: the greater the difference between the coefficient of adhesion of the two right wheels of the electric vehicle and the coefficient of adhesion of the two left wheels on the open road surface, the greater the difference between the steering angle of at least one right wheel of the electric vehicle and the steering angle of the left wheel coaxial with at least one right wheel.

[0029] In this embodiment, the greater the difference between the coefficient of adhesion of the two right wheels and the two left wheels of the electric vehicle on the open road surface, the greater the difference in grip provided by the open road surface to the two left wheels and the two right wheels. In this case, by actively controlling the steering angle of at least one right wheel of the electric vehicle to be greater than the difference in the steering angle of the left wheel coaxial with at least one right wheel, the longitudinal forces of the high-adhesion side wheel and the low-adhesion side wheel are the same or similar when there is a difference in the coefficient of adhesion of the open road surface. No additional yaw moment is generated, which can maintain the straight-line driving of the electric vehicle, ensure the longitudinal acceleration or deceleration capability of the electric vehicle, and improve the flexibility of wheel steering control.

[0030] In one embodiment of the first aspect, the control method further includes: during the process of the electric vehicle traveling in a straight line on a split road, before the steering angle of the steering wheel changes, actively controlling the absolute value of the sum of the torques output by the drive system of the electric vehicle to the two right wheels to be greater than the absolute value of the sum of the torques output to the two left wheels.

[0031] In this embodiment, when the electric vehicle is traveling straight on a split road, before the steering angle of the steering wheel changes, the absolute value of the sum of the torques output by the electric vehicle's drive system to the two right wheels is made greater than the absolute value of the sum of the torques output to the two left wheels. This allows for full utilization of the grip of the high and low sides, and the wheels of the electric vehicle will not slip, thus ensuring the electric vehicle's ability to accelerate or decelerate longitudinally.

[0032] In one embodiment of the first aspect, the control method specifically includes: the greater the difference between the coefficient of adhesion of the two right wheels and the coefficient of adhesion of the two left wheels of the electric vehicle to the open road surface, the greater the absolute value of the difference between the sum of the torques output by the drive system of the electric vehicle to the two right wheels and the sum of the torques output to the two left wheels.

[0033] In this embodiment, the greater the difference between the coefficient of adhesion of the two right wheels and the two left wheels of the electric vehicle on the split road surface, the greater the difference in grip provided by the split road surface to the two left wheels and the two right wheels. In this case, by controlling the absolute value of the difference between the sum of the torques output by the electric vehicle's drive system to the two right wheels and the sum of the torques output to the two left wheels, the grip of both the high and low adhesion sides can be fully utilized even when there are different coefficients of adhesion on the split road surface, and the wheels of the electric vehicle will not slip, thus improving the flexibility of drive system control.

[0034] In one embodiment of the first aspect, the control method specifically includes: during the electric vehicle's travel on a uniform road surface, the steering wheel turns left at a first steering wheel angle, the right front wheel is controlled to turn left at a first front wheel angle, and the right rear wheel is controlled to turn left at a first rear wheel angle. The coefficient of adhesion between the two right wheels of the electric vehicle and the two left wheels is greater than the coefficient of adhesion between the two left wheels on the opposing road surface. During the electric vehicle's travel on the opposing road surface, the steering wheel turns left at a first steering wheel angle, the right front wheel is actively controlled to turn left at a second front wheel angle, and the right rear wheel is controlled to turn left at a second rear wheel angle; wherein the first front wheel angle and the second front wheel angle are different, and the first rear wheel angle and the second rear wheel angle are different.

[0035] In this embodiment, when the electric vehicle is traveling on a uniform road surface, the driver precisely controls the vehicle's trajectory by controlling the right front wheel to turn left at a first front wheel angle and the right rear wheel to turn left at a first rear wheel angle. When the electric vehicle is traveling on a split road surface, and the steering wheel angle to the left is the same as the steering angle on a uniform road surface, the driver actively controls the right front wheel to turn left at a second front wheel angle different from the first front wheel angle and the right rear wheel to turn left at a second rear wheel angle different from the first rear wheel angle. This provides a yaw moment opposite to the yaw moment caused by the significant difference in grip when the electric vehicle is traveling on a split road surface, thus suppressing the electric vehicle's yaw.

[0036] In this embodiment, the active control of the electric vehicle during a left turn on a two-way road is described in detail as an example. The situation is completely similar when the electric vehicle is turning right on a two-way road, and will not be described in detail here.

[0037] In one embodiment of the first aspect, the control method specifically includes: when the opening degree of the accelerator pedal is greater than a preset accelerator pedal opening degree, actively controlling the second front wheel angle to be less than the first front wheel angle and the second rear wheel angle to be greater than the first rear wheel angle.

[0038] In this embodiment, when the accelerator pedal opening is greater than a preset accelerator pedal opening, the yaw moment of the electric vehicle provided by the lateral force of the wheels is reduced by actively controlling the angle of the second front wheel to be smaller than the angle of the first front wheel. This reduces the yaw moment of the electric vehicle, and when combined with the counterclockwise yaw moment caused by the significant difference in grip when the electric vehicle is traveling on a split road surface, the total yaw moment remains the same as the yaw moment required for turning, thus suppressing the yaw of the electric vehicle. Furthermore, by actively controlling the angle of the second rear wheel to be greater than the angle of the first rear wheel, the increased lateral force of the right rear wheel can compensate for the decreased lateral force of the right front wheel. The overall lateral force of the electric vehicle remains unchanged, and it does not affect the sideslip angle of the electric vehicle's center of gravity, ensuring the stability of the electric vehicle when traveling on a split road surface.

[0039] In one embodiment of the first aspect, the control method specifically includes: when the opening of the brake pedal is greater than a preset brake pedal opening, actively controlling the second front wheel angle to be greater than the first front wheel angle and the second rear wheel angle to be less than the first rear wheel angle.

[0040] In this embodiment, when the brake pedal opening is greater than a preset brake pedal opening, the yaw moment of the electric vehicle is increased by actively controlling the angle of the second front wheel to be greater than the angle of the first front wheel. This compensates for the counterclockwise yaw moment caused by the significant difference in grip when the electric vehicle is traveling on opposite sides of the road, while maintaining the total yaw moment as required for turning, thus suppressing the yaw of the electric vehicle. Furthermore, by actively controlling the angle of the second rear wheel to be smaller than the angle of the first rear wheel, the reduced lateral force of the right rear wheel can balance the increased lateral force of the right front wheel. The overall lateral force of the electric vehicle remains unchanged, thus not affecting the sideslip angle of the electric vehicle's center of gravity, ensuring the stability of the electric vehicle when traveling on opposite sides of the road.

[0041] In one embodiment of the first aspect, the control method specifically includes: the greater the difference between the adhesion coefficients of the two right wheels of the electric vehicle and the adhesion coefficients of the two left wheels on the open road surface, the greater the difference between the angles of the second front wheel and the first front wheel, and the greater the difference between the angles of the second rear wheel and the first rear wheel.

[0042] In this embodiment, the greater the difference between the adhesion coefficients of the two right wheels and the two left wheels of the electric vehicle on the opposing road surface, the greater the difference in grip provided by the opposing road surface to the two left and two right wheels. This larger difference in grip results in a greater yaw moment, leading to more severe yaw of the electric vehicle. In this situation, by actively controlling the difference between the angles of the second and first front wheels to be greater, the front wheels provide greater resistance to the larger yaw moment generated by the significant difference in grip on the opposing road surface, thus suppressing the yaw of the electric vehicle. Furthermore, by actively controlling the difference between the angles of the second and first rear wheels to be greater, the change in lateral force of the right rear wheel can balance the change in lateral force of the right front wheel, keeping the overall lateral force of the electric vehicle unchanged and not affecting the sideslip angle of the electric vehicle's center of gravity, thus ensuring the stability of the electric vehicle when traveling on the opposing road surface.

[0043] In one embodiment of the first aspect, the control method further includes: during the process of the electric vehicle making a left turn on a single road, actively controlling the absolute value of the difference between the sum of the torques output by the drive system of the electric vehicle to the two right wheels and the sum of the torques output to the two left wheels to be a first value; during the process of the electric vehicle making a left turn on a double road, actively controlling the absolute value of the difference between the sum of the torques output by the drive system of the electric vehicle to the two right wheels and the sum of the torques output to the two left wheels to be a second value; wherein the first value is less than the second value.

[0044] In this embodiment, during the electric vehicle's left turn on a single road, the absolute value of the difference between the sum of the torques output to the two right wheels and the sum of the torques output to the two left wheels by the actively controlled electric vehicle's drive system is a first value. During the electric vehicle's left turn on a split road, a second value is achieved where the absolute value of the difference between the sum of the torques output to the two right wheels and the sum of the torques output to the two left wheels by the actively controlled electric vehicle's drive system is greater than the first value. This ensures full utilization of the grip on both the high and low sides, prevents wheel slippage, and guarantees the electric vehicle's ability to accelerate or decelerate longitudinally.

[0045] Secondly, embodiments of this application provide a controller, which is used to: control the wheel steering of an electric vehicle according to the direction and angle of the steering wheel rotation when the electric vehicle is traveling on a uniform road surface; actively control the wheel steering of the electric vehicle before the steering angle of the steering wheel changes when the electric vehicle is traveling straight on a split road surface; and actively control the wheels of the electric vehicle to return to center after the electric vehicle leaves the split road surface before the steering angle of the steering wheel changes. Wherein, the difference between the coefficient of adhesion between the two coaxial wheels and the road surface is less than a preset value when the electric vehicle is traveling on a uniform road surface, and the difference between the coefficient of adhesion between the two coaxial wheels and the road surface is greater than a preset value when the electric vehicle is traveling on a split road surface.

[0046] Thirdly, embodiments of this application provide an electric vehicle, which includes a controller and four wheels, wherein:

[0047] The controller is used to: control the wheel steering of an electric vehicle based on the direction and angle of the steering wheel rotation when the electric vehicle is traveling on a uniform road surface; actively control the wheel steering of the electric vehicle before the steering wheel angle changes when the electric vehicle is traveling straight on a split road surface; and actively control the wheels to return to center after the electric vehicle leaves the split road surface before the steering wheel angle changes. Specifically, when the electric vehicle is traveling on a uniform road surface, the difference in the coefficient of adhesion between the two coaxial wheels and the road surface is less than a preset value; when the electric vehicle is traveling on a split road surface, the difference in the coefficient of adhesion between the two coaxial wheels and the road surface is greater than a preset value.

[0048] The supplementary solutions and technical effects provided in the second and third aspects above can be found in the corresponding descriptions in the first aspect, and will not be repeated here. Attached Figure Description

[0049] Figure 1 A schematic diagram of an electric vehicle provided in an embodiment of this application is shown;

[0050] Figure 2 A schematic diagram of a driving system provided in an embodiment of this application is shown;

[0051] Figure 3 A schematic diagram of a steering system provided in an embodiment of this application is shown;

[0052] Figure 4 A schematic diagram of a control method for an electric vehicle provided in an embodiment of this application is shown;

[0053] Figure 5 A schematic diagram of a driving scenario provided by an embodiment of this application is shown;

[0054] Figure 6 A schematic diagram of another control method for an electric vehicle provided in an embodiment of this application is shown;

[0055] Figure 7 A timing diagram showing the steering angle of a steering wheel, the steering angles of the two left wheels, and the steering angles of the two right wheels provided in an embodiment of this application is shown.

[0056] Figure 8 A schematic diagram of another control method for an electric vehicle provided in an embodiment of this application is shown;

[0057] Figure 9This paper presents a timing diagram showing the steering angle of a steering wheel, the torque output by the drive system, the vehicle speed of an electric vehicle, and the wheel speed according to an embodiment of this application.

[0058] Figure 10 A schematic diagram showing the steering angle of the right front wheel and the steering angle of the right rear wheel according to an embodiment of this application is shown;

[0059] Figure 11 A schematic diagram showing another right front wheel steering angle and right rear wheel steering angle provided in an embodiment of this application is shown;

[0060] Figure 12 A schematic diagram of a controller provided in an embodiment of this application is shown;

[0061] Figure 13 A schematic diagram of the operating logic of a controller provided in an embodiment of this application is shown. Detailed Implementation

[0062] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0063] The use of prefixes such as "first" and "second" in this application embodiment is solely for distinguishing different descriptive objects and does not limit the position, order, priority, quantity, or content of the described objects. The use of ordinal numbers and other prefixes to distinguish descriptive objects in this application embodiment does not constitute a limitation on the described objects. The description of the described objects is found in the claims or the context of the embodiments, and the use of such prefixes should not constitute unnecessary restrictions.

[0064] When an electric vehicle is traveling on a split road, the difference in grip provided by the split road to the left and right wheels can cause the electric vehicle to veer.

[0065] Therefore, this application provides a control method, controller, and electric vehicle for an electric vehicle. When the electric vehicle is traveling on a uniform road surface, the steering of the wheels is controlled according to the direction and angle of the steering wheel rotation, allowing the driver to precisely control the vehicle's trajectory by operating the steering wheel. When the electric vehicle is traveling straight on a split road surface, before the steering wheel angle changes, the wheel steering is actively controlled. Even without the driver operating the steering wheel direction and angle, this actively balances the yaw moment caused by the significant difference in grip, suppressing yaw and improving the stability of the electric vehicle on split road surfaces. This reduces the driver's operational complexity and improves the driving experience. After the electric vehicle leaves the split road surface, before the steering wheel angle changes, the wheels are actively controlled to return to center, preventing the wheels from remaining on the split road surface and causing yaw, thus returning the electric vehicle to a normal driving state.

[0066] See Figure 1 , Figure 1 A schematic diagram of an electric vehicle provided in an embodiment of this application is shown. (As shown) Figure 1 As shown, the electric vehicle 100 includes a drive system 110, a power battery 120, a central controller 130, and a steering system 140. The drive system 110 drives the electric vehicle 100. The power battery 120 provides electrical energy to the drive system 110 and the steering system 140. The central controller 130 controls the drive system 110 and the steering system 140. The steering system 140 steers the wheels of the electric vehicle 100. The drive system 110 can also be referred to as a powertrain.

[0067] Based on their position within the electric vehicle 100, the wheels can be categorized as follows: left front wheel (FL), right front wheel (FR), left rear wheel (BL), and right rear wheel (BR). In terms of axle arrangement, the left and right front wheels are coaxial and connected via the front axle. The left and right rear wheels are coaxial and connected via the rear axle. In terms of position, the left and left rear wheels are on the same side (left side), and the right front and right rear wheels are on the same side (right side). In other words, in the electric vehicle 100, the left and right front wheels are coaxial, as are the left and right rear wheels; the left and left rear wheels are on the same side, as are the right and right rear wheels.

[0068] The electric vehicle 100 in this application embodiment can be any of different types of automobiles such as cars, trucks, and passenger buses, or it can be a tricycle, two-wheeled vehicle, train, or other transportation device that carries people or goods, or other types of vehicles powered by power batteries. This application embodiment does not limit this.

[0069] SeeFigure 2 , Figure 2 A schematic diagram of a driving system provided in an embodiment of this application is shown.

[0070] Figure 2 The electric vehicle 100 shown in (a) is a three-wheel drive vehicle. The drive system 110 includes drive motors 111 for the two front wheels and motor controllers 121 for the drive motors 111, drive motor 112 for the left rear wheel and motor controllers 122 for the drive motor 112, and drive motor 113 for the right rear wheel and motor controllers 123 for the drive motor 113.

[0071] When the electric vehicle 100 is in a driving state, each drive motor in the drive system 110 provides driving force to the electric vehicle 100. Specifically, when the electric vehicle 100 is in a driving state, the central controller 130 calculates the torque demand of the electric vehicle and outputs torque signals to the motor controllers of each drive motor. Each motor controller receives torque signals from the power battery 120 (e.g., ...). Figure 1 The electrical energy (as shown) is used to control the torque indicated by the output torque signal of the corresponding drive motor.

[0072] When the electric vehicle 100 is in a driving state, during the forward movement of the electric vehicle 100, each drive motor transmits positive torque to the wheels of the electric vehicle 100 to provide driving force to the electric vehicle 100. The positive torque is in the same direction as the wheels rotate when the electric vehicle is moving forward.

[0073] During the reverse movement of the electric vehicle 100, each drive motor supplies reverse torque to the wheels of the electric vehicle 100 to provide driving force to the electric vehicle 100. The reverse torque is in the same direction as the wheels rotate when the electric vehicle reverses.

[0074] In particular, each drive motor in the electric vehicle 100 with energy recovery function can also be used to provide braking force for the electric vehicle 100. Specifically, when the electric vehicle 100 is in a braking state, the central controller 130 receives a braking signal and sends an energy recovery command to each motor controller. Each motor controller responds to the energy recovery command and controls the corresponding drive motor to operate in a power generation state. Each drive motor converts the kinetic energy of the electric vehicle's wheels into electrical energy and outputs reverse torque to the wheels of the electric vehicle 100 to provide braking force for the electric vehicle 100.

[0075] The drive system 110 and the central controller 130 are connected via communication, and the specific communication connection method is not limited in this embodiment. For example, the motor controller in the drive system 110 and the central controller 130 can communicate via a private CAN network, or they can communicate via a public CAN network.

[0076] See Figure 2 (b) The electric vehicle 100 is a four-wheel drive vehicle, and the drive system 110 includes a drive motor 114 for the left front wheel and a motor controller 124 for the drive motor 114, a drive motor 115 for the right front wheel and a motor controller 125 for the drive motor 115, a drive motor 112 for the left rear wheel and a motor controller 122 for the drive motor 112, and a drive motor 113 for the right rear wheel and a motor controller 123 for the drive motor 113.

[0077] The drive system 110 and the central controller 130 are connected via communication, and the specific communication connection method is not limited in this embodiment. For example, the motor controller in the drive system 110 and the central controller 130 can communicate via a private CAN network, or they can communicate via a public CAN network.

[0078] See Figure 3 , Figure 3 A schematic diagram of a steering system provided in an embodiment of this application is shown.

[0079] Figure 3 The steering system 140 shown in (a) includes a steering motor 141 for two front wheels, a steering controller 142 and a steering actuator 143 for the steering motor 141, a steering motor 144 for two rear wheels, a steering controller 145 and a steering actuator 146 for the steering motor 144.

[0080] The steering motor 141 provides driving force for the steering of the two front wheels, and the steering motor 144 provides driving force for the steering of the two rear wheels. The steering controller 142 controls the output torque of the steering motor 141, and the steering controller 145 controls the output torque of the steering motor 144. The steering actuator 143 converts the rotational motion of the output torque of the steering motor 141 into linear motion to drive the steering of the two front wheels, and the steering actuator 146 converts the rotational motion of the output torque of the steering motor 144 into linear motion to drive the steering of the two front wheels. In other words, one steering controller controls one steering motor to output torque to drive one steering actuator to steer one wheel.

[0081] During the steering process of the electric vehicle, the steering controller 142 receives a steering angle signal from the central controller 130 and a signal from the power battery 120 (e.g., ...). Figure 1 The electrical energy (as shown) is used to control the steering motor 141 to output torque according to the steering angle indicated by the steering angle signal, driving the steering actuator 143 to steer the two front wheels. The steering controller 145 receives the steering angle signal from the central controller 130 and receives the power battery 120 (as shown) Figure 1The electrical energy (shown) controls the output torque of the steering motor 144 according to the steering angle indicated by the steering angle signal, driving the steering actuator 146 to steer the two rear wheels.

[0082] The steering motors 141 and 144 output torque in the same direction, and the two wheels they drive steer in the same direction. Each output torque includes a forward torque and a reverse torque. When the steering motor outputs forward torque and reverse torque, the wheels steer in opposite directions. For example, when the steering motor outputs forward torque, the wheel it drives steers to the left, and when it outputs reverse torque, the wheel it drives steers to the right.

[0083] Figure 3 The steering system 140 shown in (b) is a four-wheel independent steering system, including a steering motor 147 for the left front wheel, a steering controller 148 and a steering actuator 149 for the steering motor 147, a steering motor 150 for the right front wheel, a steering controller 151 and a steering actuator 152 for the steering motor 150, a steering motor 153 for the left rear wheel, a steering controller 154 and a steering actuator 155 for the steering motor 153, and a steering motor 156 for the right rear wheel, a steering controller 157 and a steering actuator 158 for the steering motor 156.

[0084] One steering motor provides driving force for steering one wheel. A steering controller controls the output torque of the steering motor. A steering actuator converts the rotational motion of the steering motor's output torque into linear motion, driving the steering of one wheel. Specifically, a steering controller controls the output torque of the steering motor to drive a steering actuator to steer one wheel; for example, steering controller 148 controls the output torque of steering motor 147 to drive steering actuator 149 to steer the left front wheel.

[0085] The steering system 140 and the central controller 130 are connected via communication, and the specific communication connection method is not limited in this embodiment. For example, the steering controller in the steering system 140 and the central controller 130 can communicate via a private CAN network, or they can communicate via a public CAN network.

[0086] The architecture of the embodiments of this application has been described above. The control method for electric vehicles provided by this application will be described below with reference to specific embodiments.

[0087] The present application provides a control method for electric vehicles that improves the stability of electric vehicles traveling on split-level roads by actively adjusting the steering angle of the wheels.

[0088] The electric vehicle control method provided in this application includes the following steps.

[0089] When an electric vehicle is traveling on a uniform road surface, the steering of the wheels is controlled based on the direction and angle of the steering wheel rotation. Specifically, the difference in the coefficient of friction between the two wheels on the same axle and the road surface is less than a preset value during this process.

[0090] If the difference between the adhesion coefficients of the two wheels on the same axle and the road surface is less than the preset value, it means that the adhesion coefficients of the two wheels on the same axle are the same or have a small difference. For example, if the two wheels on the same axle are driving on an asphalt road, the uniform road surface provides the two wheels on the same axle with the same or small grip.

[0091] When an electric vehicle is traveling on a uniform road surface, the driver can precisely control the vehicle's trajectory by adjusting the direction and angle of the steering wheel rotation to control the wheel steering.

[0092] For ease of understanding, see Figure 4 , Figure 4 This diagram illustrates a control method for an electric vehicle according to an embodiment of this application. Taking the straight-line travel of the electric vehicle as an example, the color depth represents the coefficient of adhesion of the road surface; the darker the color, the greater the coefficient of adhesion.

[0093] like Figure 4 As shown in position 1, the colors of the road surface on both sides of the electric vehicle's wheels are the same, meaning the electric vehicle is traveling on a uniform road surface.

[0094] When an electric vehicle enters a road surface with two wheels facing each other, due to the significant difference in the coefficient of friction between the left and right wheels, the electric vehicle will veer towards the side with the lower coefficient of friction. (See below) Figure 5 , Figure 5 The diagram illustrates a driving scenario provided by an embodiment of this application, wherein the lighter-colored side is the side with a lower coefficient of adhesion, which leads to reduced stability of the electric vehicle.

[0095] Thus, in one embodiment, the control method further includes: actively controlling the wheel steering of the electric vehicle before the steering angle of the steering wheel changes while the electric vehicle is traveling straight on the split-road surface. Specifically, the difference in the coefficient of adhesion between the two coaxial wheels and the road surface during the electric vehicle's travel on the split-road surface is greater than a preset value.

[0096] If the difference between the adhesion coefficients of the two wheels on the same axle and the road surface is greater than the preset value, it means that the adhesion coefficients of the two wheels on the same axle are quite different. For example, one wheel on the same axle is driving on sand, while the other wheel on the same axle is driving on asphalt.

[0097] When an electric vehicle is traveling on a split road, the grip provided to the left and right wheels by the split road is significantly different. Due to the significant difference in grip, the electric vehicle will generate an additional yaw moment, causing the electric vehicle to yaw.

[0098] In this situation, by actively controlling the steering of the electric vehicle's wheels, without changing the steering angle of the steering wheel (i.e., without the driver operating the direction and angle of the steering wheel), the lateral force of the actively steered wheels can actively balance the yaw moment caused by the large difference in grip force, suppressing the yaw of the electric vehicle, so that the electric vehicle can maintain straight-line driving on the opposite road surface.

[0099] Among them, actively controlling the wheel steering of an electric vehicle means that the controller of the electric vehicle senses that the electric vehicle is traveling on the opposite road and actively issues a command to control the wheel steering of the electric vehicle, rather than responding to the input of the driver operating the steering wheel to control the wheel steering of the electric vehicle.

[0100] See also Figure 4 ,exist Figure 4 The direction of the arrow perpendicular to the vehicle body indicates the direction of wheel steering, and the size of the arrow indicates the angle of wheel steering. For example... Figure 4 As shown in position 2, the colors of the road surface on both sides of the electric vehicle's wheels are different, meaning the electric vehicle is traveling on opposite sides of the road surface and the wheels of the electric vehicle are turning.

[0101] In one embodiment, the steering of all four wheels of an electric vehicle can be actively controlled, or the steering of any two wheels of the electric vehicle can be actively controlled, including the steering of two wheels on the same side (e.g., ...). Figure 4 (as shown in position 2) and the two wheels on the same axle turn.

[0102] In one embodiment, the control method further includes: actively controlling the wheels of the electric vehicle to return to center after the electric vehicle leaves the opposite road surface and before the steering angle of the steering wheel changes.

[0103] After the electric vehicle leaves the opposite road surface, before the steering wheel angle changes, the wheels of the electric vehicle are actively controlled to return to center, so as to prevent the electric vehicle from yawing due to the wheels still being on the opposite road surface, and thus return the electric vehicle to normal driving state.

[0104] Among them, the wheel return of an electric vehicle refers to the electric vehicle's wheels returning to the position of straight-line travel, that is, the steering angle is zero.

[0105] See also Figure 4 ,like Figure 4As shown in position 3, the colors of the road surface on both sides of the electric vehicle's wheels are the same, meaning that when the electric vehicle leaves the opposite road surface, the wheels of the electric vehicle return to center.

[0106] In this embodiment, while the electric vehicle is traveling on a uniform road surface, the steering of the electric vehicle's wheels is controlled according to the direction and angle of the steering wheel rotation, allowing the driver to precisely control the vehicle's trajectory by operating the steering wheel. When the electric vehicle is traveling straight on a split road surface, before the steering wheel angle changes, the active control of the wheel steering allows the lateral force of the actively steered wheels to actively balance the yaw moment caused by the significant difference in grip, suppressing yaw and improving the vehicle's stability on split road surfaces. This reduces the driver's operational complexity and enhances the driving experience. After the electric vehicle leaves the split road surface, before the steering wheel angle changes, the wheels are actively controlled to return to center, preventing the wheels from remaining steered on the split road surface and causing yaw, thus returning the electric vehicle to a normal driving state.

[0107] In order to ensure that electric vehicles can fully utilize the traction provided by the split road surface for acceleration or deceleration after entering the split road, and to prevent the wheels of the electric vehicles from slipping.

[0108] Thus, in one embodiment, the control method further includes: during the process of the electric vehicle traveling straight on the split road, before the steering angle of the steering wheel changes, actively controlling the sum of the torques output by the electric vehicle's drive system to the two right wheels to be equal to the sum of the torques output to the two left wheels; after the electric vehicle leaves the split road, before the steering angle of the steering wheel changes, actively controlling the sum of the torques output by the electric vehicle's drive system to the two right wheels to be equal to the sum of the torques output to the two left wheels.

[0109] When an electric vehicle is driving on a split road, by actively controlling the sum of the torques output to the two right wheels to be different from the torques output to the two left wheels, the drive system actively adjusts the torques output to the high-tether wheels and the low-tether wheels to make full use of the grip of the high-tether and low-tether wheels, and the wheels of the electric vehicle do not slip, thereby improving the acceleration or deceleration performance of the electric vehicle.

[0110] See also Figure 4 ,exist Figure 4 The direction of the arrow parallel to the vehicle body indicates the direction of the torque output by the drive system, and the size of the arrow indicates the magnitude of the torque output by the drive system.

[0111] like Figure 4As shown in position 1, the sum of the torques output by the drive system to the two left wheels is equal to the sum of the torques output by the drive system to the two right wheels; as Figure 4 As shown in position 2, the sum of the torques output by the drive system to the two left wheels is less than the sum of the torques output by the drive system to the two right wheels; as Figure 4 As shown in position 3, the sum of the torques output by the drive system to the two left wheels is equal to the sum of the torques output by the drive system to the two right wheels.

[0112] It should be noted that the schemes for actively controlling the torque output of the drive system and actively controlling wheel steering can be used individually or in combination.

[0113] In this embodiment, while the electric vehicle is traveling on a split-level road, the sum of the torques output to the two right wheels is actively controlled to be different from the torques output to the two left wheels. This actively adjusts the torque output to the high-touch and low-touch wheels of the drive system, fully utilizing the traction of both sides and preventing wheel slippage, thus improving the acceleration and deceleration performance of the electric vehicle. After the electric vehicle leaves the split-level road, before the steering wheel angle changes, the sum of the torques output to the two right wheels of the drive system is actively controlled to be equal to the sum of the torques output to the two left wheels, maintaining the electric vehicle's straight-line travel.

[0114] The following will provide a detailed explanation of the active control of electric vehicles during straight-line travel on a split road.

[0115] Specifically, taking the case where the adhesion coefficient of the two right wheels of the split road surface is greater than that of the two left wheels as an example, and the case where the adhesion coefficient of the two right wheels of the split road surface is less than that of the two left wheels is exactly the same, and will not be elaborated on here.

[0116] In one embodiment, the control method specifically includes: the adhesion coefficient of the two right wheels of the electric vehicle to the open road surface is greater than the adhesion coefficient of the two left wheels; during the process of the electric vehicle traveling straight on the open road surface, before the steering angle of the steering wheel changes, actively controlling the steering angle of at least one right wheel of the electric vehicle to be greater than the steering angle of the left wheel that is coaxial with at least one right wheel.

[0117] When the coefficient of adhesion of the two right wheels of an electric vehicle to the two split-surface road surface is greater than that to the two left wheels, the grip provided by the split-surface road surface to the two right wheels is greater than that provided to the two left wheels.

[0118] According to the tire friction circle theory, the gripping force has a longitudinal component (i.e., the forward or backward direction of the electric vehicle) called longitudinal force (including driving force and braking force) and a lateral component (perpendicular to the forward or backward direction of the electric vehicle) called lateral force.

[0119] When an electric vehicle is traveling in a straight line on a split road, by actively controlling the steering angle of at least one right wheel of the electric vehicle to be greater than the steering angle of the left wheel that is coaxial with at least one right wheel, the lateral force of at least one wheel on the high-attachment side is actively adjusted to be larger and the lateral force of the wheel on the low-attachment side coaxial with the low-attachment side is smaller. This makes the longitudinal forces of the high-attachment side wheel and the low-attachment side wheel the same or similar, and no additional yaw moment is generated, so that the electric vehicle can maintain straight-line driving.

[0120] Among them, at least one right wheel has the same steering direction as the left wheel that is coaxial with at least one right wheel.

[0121] See also Figure 6 In position 2, the right front wheel turns to the right at a greater angle than the left front wheel turns to the right.

[0122] In one embodiment, the steering angle of at least one right wheel of the electric vehicle can be actively controlled to be greater than the steering angle of the left wheel coaxial with the at least one right wheel throughout the entire period of the electric vehicle's straight-line travel on the split-road surface. Alternatively, the steering angle of at least one right wheel of the electric vehicle can be actively controlled to be greater than the steering angle of the left wheel coaxial with the at least one right wheel for a partial period of time. In other words, the action of actively controlling the steering angle of at least one right wheel of the electric vehicle to be greater than the steering angle of the left wheel coaxial with the at least one right wheel can occur at any moment during the electric vehicle's straight-line travel on the split-road surface.

[0123] In this embodiment, when the coefficient of adhesion of the two right wheels of the electric vehicle to the opposing road surface is greater than that to the two left wheels, by actively controlling the steering angle of at least one right wheel of the electric vehicle to be greater than the steering angle of the left wheel coaxial with at least one right wheel, the lateral force of at least one wheel on the high-adhesion side is actively adjusted to be larger and the lateral force of the wheel coaxial with the low-adhesion side is smaller, so that the longitudinal force of the wheel on the high-adhesion side is close to or the same as that of the wheel on the low-adhesion side, and the electric vehicle can still maintain straight-line driving on the opposing road surface.

[0124] In one embodiment, the control method specifically includes: when the electric vehicle is traveling straight on a split road, before the steering angle of the steering wheel changes, when the opening of the accelerator pedal is greater than a preset accelerator pedal opening, actively controlling the two front wheels of the electric vehicle to turn to the right and the steering angle of the two rear wheels to be zero.

[0125] The preset accelerator pedal opening is a small value. If the accelerator pedal opening is greater than the preset accelerator pedal opening, it indicates that the user intends to operate the accelerator pedal to accelerate the electric vehicle.

[0126] During the acceleration of an electric vehicle, a counterclockwise yaw moment is generated because the grip provided by the road surface to the left and right wheels is significantly different. By actively controlling the two front wheels of the electric vehicle to turn to the right and the two rear wheels to turn at zero angle, the lateral force of the turned wheels can provide a yaw moment that counteracts the counterclockwise yaw moment, thereby suppressing the yaw of the electric vehicle.

[0127] See Figure 6 , Figure 6 A schematic diagram of another control method for an electric vehicle provided in an embodiment of this application is shown.

[0128] like Figure 6 As shown in (a), the two front wheels turn to the right, while the two rear wheels do not turn.

[0129] In this embodiment, when the electric vehicle is traveling straight on a split-road surface, the system automatically detects the user's intention to accelerate the vehicle by detecting that the accelerator pedal opening is greater than a preset accelerator pedal opening. When the accelerator pedal opening is greater than the preset accelerator pedal opening, the system actively controls the two front wheels of the electric vehicle to turn to the right and the two rear wheels to turn at zero angle. This ensures that the lateral force of the turned wheels provides a counteracting yaw moment that is generated due to the significant difference in grip caused by the electric vehicle traveling on a split-road surface, thereby suppressing the yaw of the electric vehicle.

[0130] In one embodiment, the control method specifically includes: when the electric vehicle is traveling straight on a split road, before the steering angle of the steering wheel changes, when the opening of the brake pedal is greater than a preset brake pedal opening, actively controlling the two front wheels of the electric vehicle to turn to the left and the steering angle of the two rear wheels to be zero.

[0131] The preset brake pedal opening is a small value. If the brake pedal opening is greater than the preset brake pedal opening, it indicates that the user intends to operate the brake pedal to brake the electric vehicle.

[0132] During the braking process of an electric vehicle, due to the significant difference in grip provided by the road surface to the left and right wheels, a clockwise yaw moment is generated. By actively controlling the two front wheels of the electric vehicle to turn to the left and the two rear wheels to turn at zero angles, the lateral force of the turned wheels can provide a yaw moment that counteracts the clockwise yaw moment, thereby suppressing the yaw of the electric vehicle.

[0133] In this embodiment, when the electric vehicle is traveling straight on a split-road surface, the system automatically detects the user's intention to brake by detecting that the brake pedal opening is greater than a preset brake pedal opening. When the brake pedal opening is greater than the preset brake pedal opening, the system actively controls the two front wheels of the electric vehicle to turn to the left and the two rear wheels to turn at zero angle. This ensures that the lateral force of the turned wheels provides a counteracting yaw moment caused by the significant difference in grip between the electric vehicle and the road surface, thereby suppressing the yaw of the electric vehicle.

[0134] In one embodiment, the control method specifically includes: when the electric vehicle is traveling straight on a split road, before the steering angle of the steering wheel changes, when the opening of the accelerator pedal is greater than a preset accelerator pedal opening, actively controlling the two front wheels of the electric vehicle to turn right and the two rear wheels to turn left.

[0135] During the acceleration of an electric vehicle, due to the significant difference in grip provided by the road surface to the left and right wheels, a counterclockwise yaw moment is generated. By actively controlling the two front wheels of the electric vehicle to turn right and the two rear wheels to turn left, the lateral forces of the two front wheels and the two rear wheels work together to provide a yaw moment that counteracts the clockwise yaw moment, thereby reducing the sideslip angle of the electric vehicle and suppressing the yaw of the electric vehicle.

[0136] See Figure 6 ,like Figure 7 As shown in (b), the two front wheels turn to the right and the two rear wheels turn to the left.

[0137] In this embodiment, when the electric vehicle is traveling straight on a split road, if the accelerator pedal opening is greater than the preset accelerator pedal opening, the two front wheels of the electric vehicle are actively controlled to turn right and the two rear wheels to turn left. This allows the lateral forces of the front and rear wheels after turning to work together to provide a counter-clockwise yaw moment that counteracts the counter-clockwise yaw moment caused by the large difference in grip force when the electric vehicle is traveling on a split road. This reduces the sideslip angle of the electric vehicle and suppresses the yaw of the electric vehicle.

[0138] In one embodiment, the control method specifically includes: when the electric vehicle is traveling straight on a split road, before the steering angle of the steering wheel changes, when the opening of the brake pedal is greater than a preset brake pedal opening, actively controlling the two front wheels of the electric vehicle to turn to the left and the two rear wheels to turn to the right.

[0139] During the braking process of an electric vehicle, due to the significant difference in grip provided by the road surface to the left and right wheels, a clockwise yaw moment is generated. By actively controlling the two front wheels of the electric vehicle to turn left and the two rear wheels to turn right, the lateral forces of the two front wheels and the two rear wheels work together to provide a yaw moment that counteracts the clockwise yaw moment, thereby reducing the sideslip angle of the electric vehicle and suppressing the yaw of the electric vehicle.

[0140] In this embodiment, when the electric vehicle is traveling straight on a split road, if the brake pedal opening is greater than the preset brake pedal opening, the two front wheels of the electric vehicle are actively controlled to turn left and the two rear wheels to turn right. This allows the lateral forces of the front and rear wheels after turning to work together to provide a yaw moment that counteracts the clockwise yaw moment caused by the large difference in grip force when the electric vehicle is traveling on a split road. This reduces the sideslip angle of the electric vehicle and suppresses the yaw of the electric vehicle.

[0141] In one embodiment, the control method specifically includes: when the electric vehicle is traveling straight on a split road, before the steering angle of the steering wheel changes, actively controlling the two right wheels of the electric vehicle to turn in different directions and the two left wheels to turn at zero angles.

[0142] When an electric vehicle is traveling in a straight line on a split road, by actively controlling the two right wheels of the electric vehicle to steer in different directions, the high-attached wheel provides a yaw moment to counteract the yaw moment caused by the large difference in grip force. At the same time, the lateral forces of the two high-attached wheels can be balanced, that is, the lateral forces of the right front wheel and the right rear wheel can be balanced. This reduces the sideslip angle of the electric vehicle's center of gravity and improves the stability of the electric vehicle when traveling on a split road.

[0143] And by actively controlling the steering angle of the two left wheels to zero, the low-tether side wheels are used only to provide longitudinal force, enabling electric vehicles to achieve maximum longitudinal acceleration or deceleration.

[0144] In one embodiment, the steering of the right front wheel and the right rear wheel can be actively controlled with the goal of equalizing the lateral force after the right front wheel turns with the right rear wheel turns.

[0145] In one embodiment, the control method specifically includes: actively controlling the steering angle of the right rear wheel to increase as the steering angle of the right front wheel increases, so that the lateral force of the right rear wheel can be balanced with the lateral force of the right front wheel under different steering angles of the right front wheel, thereby reducing the center of gravity sideslip angle of the electric vehicle.

[0146] See Figure 7 , Figure 7The diagram shows a timing diagram of the steering angle of a steering wheel, the steering angles of the two left wheels, and the steering angles of the two right wheels, according to an embodiment of this application.

[0147] like Figure 7 As shown, before the first time t1, the electric vehicle travels on a uniform road surface. Between the first time t1 and the second time t2, the electric vehicle travels on a split road surface. After the second time t2, the electric vehicle leaves the split road surface.

[0148] Before the first moment t1, the steering wheel angle is zero, and the steering angles of both left wheels and both right wheels are also zero.

[0149] Between the first time t1 and the second time t2, the steering wheel angle is zero, the steering angle of both left wheels is zero, the right front wheel turns to the right, and the right rear wheel turns to the left.

[0150] After the second moment t2, the steering wheel angle is zero, the steering angles of the two left wheels are zero, and the two right wheels return to center.

[0151] In this embodiment, during the straight-line travel of the electric vehicle on a split-road surface, before the steering angle of the steering wheel changes, the two right wheels of the electric vehicle are actively controlled to steer in different directions. This ensures that after active steering, the lateral force of the high-tether side wheel provides a yaw moment to counteract the yaw moment caused by the significant difference in grip, while the lateral forces of the two high-tether side wheels are balanced. That is, the lateral forces of the right front wheel and the right rear wheel are balanced, thereby reducing the sideslip angle of the electric vehicle's center of gravity and improving the stability of the electric vehicle on the split-road surface. Furthermore, by actively controlling the steering angle of the two left wheels to zero, the low-tether side wheel is only used to provide longitudinal force, enabling the electric vehicle to achieve maximum longitudinal acceleration or deceleration. This allows the electric vehicle to maintain straight-line travel with maximum longitudinal acceleration or deceleration on the split-road surface.

[0152] In one embodiment, the control method specifically includes: when the electric vehicle is traveling straight on a split road, before the steering angle of the steering wheel changes, when the opening of the accelerator pedal is greater than a preset accelerator pedal opening, actively controlling the right front wheel to turn right and the right rear wheel to turn left.

[0153] During the acceleration of an electric vehicle, due to the significant difference in grip provided by the road surface to the left and right wheels, the electric vehicle will generate a counterclockwise yaw moment. By actively controlling the right front wheel to turn right and the right rear wheel to turn left, the lateral force of the wheel after turning can provide a yaw moment that counteracts the counterclockwise yaw moment, thereby suppressing the yaw of the electric vehicle. Furthermore, the lateral forces of the right front wheel and the right rear wheel can be balanced, thereby reducing the sideslip angle of the electric vehicle's center of gravity.

[0154] See alsoFigure 4 As the electric vehicle accelerates on the opposite side of the road, the right front wheel turns to the right and the right rear wheel turns to the left, such as... Figure 8 Position 2 is shown in the middle.

[0155] In this embodiment, when the electric vehicle is traveling straight on a split-road surface, before the steering angle of the steering wheel changes, if the opening of the accelerator pedal is greater than the preset accelerator pedal opening, the right front wheel is actively controlled to turn right and the right rear wheel to turn left. This allows the lateral force of the steering wheels to provide a counter-clockwise yaw moment that counteracts the counter-clockwise yaw moment caused by the large difference in grip between the electric vehicle and the split-road surface. This suppresses the yaw of the electric vehicle, and the lateral forces of the right front wheel and the right rear wheel can be balanced, thereby reducing the sideslip angle of the electric vehicle's center of gravity and further improving the stability of the electric vehicle when traveling on a split-road surface.

[0156] In one embodiment, the control method specifically includes: when the electric vehicle is traveling straight on a split road, before the steering angle of the steering wheel changes, when the opening of the brake pedal is greater than a preset brake pedal opening, actively controlling the right front wheel to turn to the left and the right rear wheel to turn to the right.

[0157] During the braking process of an electric vehicle, due to the significant difference in grip provided by the road surface to the left and right wheels, the electric vehicle will generate a clockwise yaw moment. By actively controlling the right front wheel to turn left and the right rear wheel to turn right, the lateral force of the wheel after turning can provide a yaw moment that counteracts the clockwise yaw moment, thereby suppressing the yaw of the electric vehicle. Furthermore, the lateral forces of the right front wheel and the right rear wheel can be balanced, thereby reducing the sideslip angle of the electric vehicle's center of gravity.

[0158] See Figure 8 , Figure 8 A schematic diagram of another electric vehicle control method provided in an embodiment of this application is shown.

[0159] like Figure 9 As shown, during the braking and driving of the electric vehicle on the split road, the right front wheel turns to the left and the right rear wheel turns to the right.

[0160] In this embodiment, when the electric vehicle is traveling straight on a split-road surface, before the steering angle of the steering wheel changes, if the opening of the brake pedal is greater than the preset brake pedal opening, the right front wheel is actively controlled to turn left and the right rear wheel to turn right. This allows the lateral force of the steering wheels to provide a counteracting yaw moment caused by the significant difference in grip between the electric vehicle and the split-road surface, thereby suppressing the yaw of the electric vehicle. Furthermore, the lateral forces of the right front wheel and the right rear wheel can be balanced, reducing the sideslip angle of the electric vehicle's center of gravity and further improving the stability of the electric vehicle when traveling on a split-road surface.

[0161] In one embodiment, the control method specifically includes: the greater the difference between the coefficient of adhesion of the two right wheels of the electric vehicle and the coefficient of adhesion of the two left wheels on the open road surface, the greater the difference between the steering angle of at least one right wheel of the electric vehicle and the steering angle of the left wheel coaxial with at least one right wheel.

[0162] The greater the difference between the coefficient of friction of the two right wheels and the two left wheels of an electric vehicle on a split road surface, the greater the difference in grip provided by the split road surface to the two left wheels and the two right wheels.

[0163] In this case, by actively controlling the steering angle of at least one right wheel of the electric vehicle and the steering angle of the left wheel coaxial with at least one right wheel, the difference between the lateral force of at least one right wheel and the lateral force of the left wheel coaxial with at least one right wheel is greater, so that the longitudinal forces of the high-attachment wheel and the low-attachment wheel are the same or similar, no additional yaw moment is generated, and the straight-line driving of the electric vehicle can be maintained.

[0164] In this embodiment, the greater the difference between the coefficient of adhesion of the two right wheels and the two left wheels of the electric vehicle on the open road surface, the greater the difference in grip provided by the open road surface to the two left wheels and the two right wheels. In this case, by actively controlling the steering angle of at least one right wheel of the electric vehicle to be greater than the difference in the steering angle of the left wheel coaxial with at least one right wheel, the longitudinal forces of the high-adhesion side wheel and the low-adhesion side wheel are the same or similar when there is a difference in the coefficient of adhesion of the open road surface. No additional yaw moment is generated, which can maintain the straight-line driving of the electric vehicle, ensure the longitudinal acceleration or deceleration capability of the electric vehicle, and improve the flexibility of wheel steering control.

[0165] In one embodiment, the control method further includes: during the process of the electric vehicle traveling in a straight line on a split road, before the steering angle of the steering wheel changes, actively controlling the absolute value of the sum of the torques output by the electric vehicle's drive system to the two right wheels to be greater than the absolute value of the sum of the torques output to the two left wheels.

[0166] During the operation of an electric vehicle, due to the significant difference in grip provided to the left and right wheels by the split road surface, the absolute value of the sum of the torques output to the two right wheels by actively controlling the electric vehicle's drive system is greater than the absolute value of the sum of the torques output to the two left wheels. This allows for full utilization of the grip on the high and low sides during acceleration or deceleration, and prevents the electric vehicle's wheels from slipping.

[0167] Furthermore, by actively controlling the steering angle of at least one right wheel of the electric vehicle to be greater than the steering angle of the left wheel that is coaxial with at least one right wheel, the yaw moment caused by the torque difference between the left and right differential wheels is balanced.

[0168] In one embodiment, the absolute value of the sum of torques output by the drive system of the actively controlled electric vehicle to the two right wheels is greater than the absolute value of the sum of torques output to the two left wheels, including: when the opening of the accelerator pedal is greater than a preset accelerator pedal opening, the sum of torques output by the actively controlled drive system to the two right wheels is greater than the sum of torques output to the two left wheels.

[0169] See Figure 9 , Figure 9 The illustration shows a timing diagram of the steering wheel angle, the torque output by the drive system, the vehicle speed of the electric vehicle, and the wheel speed according to an embodiment of this application.

[0170] like Figure 10 As shown, when the electric vehicle is driving on a split road, the steering wheel angle is zero, the sum of the torques output by the drive system to the two right wheels is greater than the sum of the torques output to the two left wheels, the speed of the electric vehicle is continuously increasing, the wheel speeds of the two left wheels and the two right wheels are very close, and the wheel speeds of the two left wheels are slightly greater than the wheel speeds of the two right wheels.

[0171] In one embodiment, the absolute value of the sum of torques output by the drive system of the actively controlled electric vehicle to the two right wheels is greater than the absolute value of the sum of torques output to the two left wheels, including: when the opening of the brake pedal is greater than a preset brake pedal opening, the sum of torques output by the actively controlled drive system to the two right wheels is less than the sum of torques output to the two left wheels.

[0172] In this embodiment, when the electric vehicle is traveling straight on a split road, before the steering angle of the steering wheel changes, the absolute value of the sum of the torques output by the electric vehicle's drive system to the two right wheels is made greater than the absolute value of the sum of the torques output to the two left wheels. This allows for full utilization of the grip of the high and low sides, and the wheels of the electric vehicle will not slip, thus ensuring the electric vehicle's ability to accelerate or decelerate longitudinally.

[0173] In one embodiment, the control method specifically includes: the greater the difference between the coefficient of adhesion to the two right wheels and the coefficient of adhesion to the two left wheels of the electric vehicle on the open road surface, the greater the absolute value of the difference between the sum of the torques output by the drive system of the electric vehicle to the two right wheels and the sum of the torques output to the two left wheels.

[0174] The greater the difference between the coefficient of friction of the two right wheels and the two left wheels of an electric vehicle on a split road surface, the greater the difference in grip provided by the split road surface to the two left wheels and the two right wheels.

[0175] In this case, by controlling the absolute value of the difference between the sum of the torques output to the two right wheels and the sum of the torques output to the two left wheels of the electric vehicle's drive system, the traction of the high and low sides can be fully utilized during acceleration or deceleration, and the wheels of the electric vehicle will not slip.

[0176] In this embodiment, the greater the difference between the coefficient of adhesion of the two right wheels and the two left wheels of the electric vehicle on the split road surface, the greater the difference in grip provided by the split road surface to the two left wheels and the two right wheels. In this case, by controlling the absolute value of the difference between the sum of the torques output by the electric vehicle's drive system to the two right wheels and the sum of the torques output to the two left wheels, the grip of both the high and low adhesion sides can be fully utilized even when there are different coefficients of adhesion on the split road surface, and the wheels of the electric vehicle will not slip, thus improving the flexibility of drive system control.

[0177] The following will provide a detailed explanation of the active control of electric vehicles during left turns on opposite sides of a road. The situation is entirely similar when electric vehicles are turning right on opposite sides of a road, and will not be elaborated upon here.

[0178] Similarly, taking the case where the adhesion coefficient of the two right wheels of the split road surface is greater than that of the two left wheels as an example, the case where the adhesion coefficient of the two right wheels of the split road surface is less than that of the two left wheels is exactly the same, and will not be elaborated on here.

[0179] In one embodiment, the control method specifically includes: during the process of the electric vehicle driving on a uniform road surface, the angle at which the steering wheel turns to the left is a first steering wheel angle, the angle at which the right front wheel turns to the left is a first front wheel angle, and the angle at which the right rear wheel turns to the left is a first rear wheel angle.

[0180] Wherein, the first front wheel angle is the angle at which the front wheels turn left when the steering wheel is turned to the left at the first steering wheel angle, and the first rear wheel angle is the angle at which the rear wheels turn left when the steering wheel is turned to the left at the first steering wheel angle. It can be considered that the first front wheel angle and the first rear wheel angle are the front wheel angle and the rear wheel angle indicated by the first steering wheel angle.

[0181] When an electric vehicle has the ability to turn backward, the angle at which the rear wheels turn to the left is not zero; when an electric vehicle does not have the ability to turn backward, the angle at which the rear wheels turn to the left is zero.

[0182] In one embodiment, the control method specifically includes: the adhesion coefficient of the two right wheels of the electric vehicle to the two left wheels is greater than the adhesion coefficient of the two left wheels on the open road surface; during the electric vehicle's travel on the open road surface, the steering wheel turns to the left at a first steering wheel angle; the right front wheel is actively controlled to turn to the left at a second front wheel angle; and the right rear wheel turns to the left at a second rear wheel angle; wherein the first front wheel angle and the second front wheel angle are different, and the first rear wheel angle and the second rear wheel angle are different.

[0183] When the coefficient of adhesion of the two right wheels of an electric vehicle to the two left wheels is greater than that of the two left wheels, the grip provided by the two right wheels to the two left wheels is greater than that provided by the two left wheels. Due to the large difference in grip, a yaw moment is generated, causing the electric vehicle to yaw.

[0184] In this situation, by actively adjusting the steering angles of the right front wheel and the right rear wheel to be different from those of the first front wheel and the first rear wheel, a yaw moment opposite to the direction of the yaw moment that causes the electric vehicle to yaw is provided, thereby suppressing the yaw of the electric vehicle.

[0185] And by not adjusting the steering angle of the two left wheels, and not affecting the longitudinal force of the low-tether side wheel, the electric vehicle can still maintain the ability to accelerate or decelerate at maximum during a left turn.

[0186] See Figure 10 , Figure 10 This diagram illustrates the steering angles of the right front wheel and the right rear wheel according to an embodiment of this application.

[0187] like Figure 10 As shown, the first front wheel angle is greater than the second front wheel angle, and the first rear wheel angle is less than the second rear wheel angle.

[0188] In this embodiment, when the electric vehicle is traveling on a uniform road surface, the driver precisely controls the vehicle's trajectory by controlling the right front wheel to turn left at a first front wheel angle and the right rear wheel to turn left at a first rear wheel angle. When the electric vehicle is traveling on a split road surface, and the steering wheel angle to the left is the same as the steering angle on a uniform road surface, the driver actively controls the right front wheel to turn left at a second front wheel angle different from the first front wheel angle and the right rear wheel to turn left at a second rear wheel angle different from the first rear wheel angle. This provides a yaw moment opposite to the yaw moment caused by the significant difference in grip when the electric vehicle is traveling on a split road surface, thus suppressing the electric vehicle's yaw.

[0189] In one embodiment, when the steering wheel turns to the right at the same angle, the steering angle of the right front wheel and the steering angle of the right rear wheel are different when the electric vehicle is traveling on a split road and on a uniform road.

[0190] In one embodiment, the control method specifically includes: when the opening degree of the accelerator pedal is greater than a preset accelerator pedal opening degree, actively controlling the second front wheel angle to be less than the first front wheel angle and the second rear wheel angle to be greater than the first rear wheel angle.

[0191] During the acceleration of an electric vehicle, the difference in grip provided by the road surface to the left and right wheels is significant. This difference in grip generates a counterclockwise yaw moment. This yaw moment is superimposed on the counterclockwise yaw moment provided by the lateral force of the wheels during the left turn of the electric vehicle, making the total yaw moment greater than the yaw moment required for the turn, causing the electric vehicle to yaw.

[0192] Without changing the steering wheel angle, by actively controlling the angle of the second front wheel to be smaller than the angle of the first front wheel, such as... Figure 10 As shown, after the electric vehicle enters the opposite road surface, the angle of the right front wheel turning to the left is reduced to reduce the yaw moment of the electric vehicle and suppress the yaw of the electric vehicle.

[0193] And by actively controlling the angle of the second rear wheel to be greater than the angle of the first rear wheel, such as Figure 11 As shown, after the electric vehicle enters the opposite road surface, the steering angle of the right rear wheel is increased so that the increased lateral force of the right rear wheel can compensate for the decreased lateral force of the right front wheel. The overall lateral force of the electric vehicle does not change and does not affect the sideslip angle of the electric vehicle's center of gravity, thus maintaining the stability of the electric vehicle's steering.

[0194] In this embodiment, when the accelerator pedal opening is greater than a preset accelerator pedal opening, the yaw moment of the electric vehicle provided by the lateral force of the wheels is reduced by actively controlling the angle of the second front wheel to be smaller than the angle of the first front wheel. This reduces the yaw moment of the electric vehicle, and when combined with the counterclockwise yaw moment caused by the significant difference in grip when the electric vehicle is traveling on a split road surface, the total yaw moment remains the same as the yaw moment required for turning, thus suppressing the yaw of the electric vehicle. Furthermore, by actively controlling the angle of the second rear wheel to be greater than the angle of the first rear wheel, the increased lateral force of the right rear wheel can compensate for the decreased lateral force of the right front wheel. The overall lateral force of the electric vehicle remains unchanged, and it does not affect the sideslip angle of the electric vehicle's center of gravity, ensuring the stability of the electric vehicle when traveling on a split road surface.

[0195] In one embodiment, the control method specifically includes: when the opening of the brake pedal is greater than a preset brake pedal opening, actively controlling the second front wheel angle to be greater than the first front wheel angle and the second rear wheel angle to be less than the first rear wheel angle.

[0196] During the braking process of an electric vehicle, the difference in grip provided by the road surface to the left and right wheels is significant. This difference in grip generates a clockwise yaw moment. This yaw moment is superimposed on the counterclockwise yaw moment provided by the lateral force of the wheels during the left turn of the electric vehicle, resulting in a total yaw moment that is less than the yaw moment required for the turn, causing the electric vehicle to yaw.

[0197] Without changing the steering angle of the steering wheel, the angle of the second front wheel is actively controlled to be greater than that of the first front wheel. That is, after the electric vehicle enters the opposite road surface, the angle of the right front wheel turning to the left is increased to increase the yaw moment of the electric vehicle and suppress the yaw of the electric vehicle.

[0198] Furthermore, by actively controlling the angle of the second rear wheel to be smaller than that of the first rear wheel, that is, reducing the steering angle of the right rear wheel after the electric vehicle enters the opposite road surface, the reduced lateral force of the right rear wheel can balance the increased lateral force of the right front wheel, so that the overall lateral force of the electric vehicle does not change and does not affect the sideslip angle of the electric vehicle's center of gravity, thereby maintaining the stability of the electric vehicle's steering.

[0199] See Figure 11 , Figure 11 This illustration shows another diagram of the steering angle of the right front wheel and the steering angle of the right rear wheel provided in an embodiment of this application.

[0200] like Figure 12 As shown, the angle of the first front wheel is smaller than the angle of the second front wheel, and the angle of the first rear wheel is larger than the angle of the second rear wheel.

[0201] In this embodiment, when the brake pedal opening is greater than a preset brake pedal opening, the yaw moment of the electric vehicle is increased by actively controlling the angle of the second front wheel to be greater than the angle of the first front wheel. This compensates for the counterclockwise yaw moment caused by the significant difference in grip when the electric vehicle is traveling on opposite sides of the road, while maintaining the total yaw moment as required for turning, thus suppressing the yaw of the electric vehicle. Furthermore, by actively controlling the angle of the second rear wheel to be smaller than the angle of the first rear wheel, the reduced lateral force of the right rear wheel can balance the increased lateral force of the right front wheel. The overall lateral force of the electric vehicle remains unchanged, thus not affecting the sideslip angle of the electric vehicle's center of gravity, ensuring the stability of the electric vehicle when traveling on opposite sides of the road.

[0202] In one embodiment, the control method specifically includes: the greater the difference between the adhesion coefficients of the two right wheels and the two left wheels of the electric vehicle on the open road surface, the greater the difference between the angles of the second front wheel and the first front wheel, and the greater the difference between the angles of the second rear wheel and the first rear wheel.

[0203] The greater the difference between the coefficient of friction of the two right wheels and the coefficient of friction of the two left wheels of an electric vehicle on a road surface, the greater the difference in grip provided by the road surface to the two left wheels and the two right wheels. The greater the difference in grip, the greater the yaw moment generated by the larger difference in grip, and the more severe the yaw of the electric vehicle.

[0204] Without changing the steering angle of the steering wheel, by actively controlling the difference between the angles of the second and first front wheels, that is, the greater the change in the steering angle of the right front wheel after the electric vehicle enters the opposite road surface, the greater the yaw moment of the electric vehicle, so as to resist the greater yaw moment caused by the large difference in grip and suppress the yaw of the electric vehicle.

[0205] Furthermore, by actively controlling the difference between the second rear wheel angle and the first rear wheel angle, that is, the greater the change in the steering angle of the right rear wheel after the electric vehicle enters the opposite road surface, the change in the lateral force of the right rear wheel can balance the change in the lateral force of the right front wheel, so that the overall lateral force of the electric vehicle does not change and does not affect the center of gravity sideslip angle of the electric vehicle, thereby maintaining the steering stability of the electric vehicle.

[0206] In this embodiment, the greater the difference between the adhesion coefficients of the two right wheels and the two left wheels of the electric vehicle on the opposing road surface, the greater the difference in grip provided by the opposing road surface to the two left and two right wheels. This larger difference in grip results in a greater yaw moment, leading to more severe yaw of the electric vehicle. In this situation, by actively controlling the difference between the angles of the second and first front wheels to be greater, the front wheels provide greater resistance to the larger yaw moment generated by the significant difference in grip on the opposing road surface, thus suppressing the yaw of the electric vehicle. Furthermore, by actively controlling the difference between the angles of the second and first rear wheels to be greater, the change in lateral force of the right rear wheel can balance the change in lateral force of the right front wheel, keeping the overall lateral force of the electric vehicle unchanged and not affecting the sideslip angle of the electric vehicle's center of gravity, thus ensuring the stability of the electric vehicle when traveling on the opposing road surface.

[0207] In one embodiment, the control method further includes: during the process of the electric vehicle turning left on a single road, actively controlling the absolute value of the difference between the sum of the torques output by the drive system of the electric vehicle to the two right wheels and the sum of the torques output to the two left wheels is a first value; during the process of the electric vehicle turning left on a two-way road, actively controlling the absolute value of the difference between the sum of the torques output by the drive system of the electric vehicle to the two right wheels and the sum of the torques output to the two left wheels is a second value; wherein, the first value is less than the second value.

[0208] When an electric vehicle is turning left on a straight road, the torque difference between the left and right wheels provides a counterclockwise yaw torque to assist the electric vehicle in turning.

[0209] When an electric vehicle is turning left on a road with two wheels facing each other, a yaw moment is generated due to the large difference in grip between the left and right wheels, causing the electric vehicle to yaw.

[0210] In this case, by actively controlling the absolute value of the difference between the sum of the torques output to the two right wheels and the sum of the torques output to the two left wheels of the electric vehicle's drive system, the absolute value of the torque difference between the left and right wheels is increased, so as to make full use of the grip of the high-touch side and the low-touch side during acceleration or deceleration, and the wheels of the electric vehicle will not slip.

[0211] In this embodiment, during the electric vehicle's left turn on a single road, the absolute value of the difference between the sum of the torques output to the two right wheels and the sum of the torques output to the two left wheels by the actively controlled electric vehicle's drive system is a first value. During the electric vehicle's left turn on a split road, a second value is achieved where the absolute value of the difference between the sum of the torques output to the two right wheels and the sum of the torques output to the two left wheels by the actively controlled electric vehicle's drive system is greater than the first value. This ensures full utilization of the grip on both the high and low sides, prevents wheel slippage, and guarantees the electric vehicle's ability to accelerate or decelerate longitudinally.

[0212] This application provides a controller for an electric vehicle 100, which is used to execute the electric vehicle control method provided in the above embodiment.

[0213] The controller is used to: control the wheel steering of an electric vehicle based on the direction and angle of the steering wheel rotation when the electric vehicle is traveling on a uniform road surface; actively control the wheel steering of the electric vehicle before the steering wheel angle changes when the electric vehicle is traveling straight on a split road surface; and actively control the wheels to return to center after the electric vehicle leaves the split road surface before the steering wheel angle changes. Specifically, when the electric vehicle is traveling on a uniform road surface, the difference in the coefficient of adhesion between the two coaxial wheels and the road surface is less than a preset value; when the electric vehicle is traveling on a split road surface, the difference in the coefficient of adhesion between the two coaxial wheels and the road surface is greater than a preset value.

[0214] See Figure 12 , Figure 12 A schematic diagram of a controller provided in an embodiment of this application is shown.

[0215] like Figure 13 As shown, the controller receives wheel speed signals, yaw rate signals, steering wheel signals, and pedal signals. When determining whether the electric vehicle is traveling on a uniform road surface based on these signals, it sends a steering angle signal to the steering controller to control the steering of the electric vehicle's wheels based on the direction and angle of the steering wheel rotation. When determining whether the electric vehicle is traveling in a straight line on a split road surface based on these signals, it actively sends a steering angle signal to the steering controller to control the steering of the electric vehicle's wheels. After determining whether the electric vehicle has left the split road surface, it actively sends a steering angle signal to the steering controller to control the steering motor to drive the electric vehicle's wheels back to center.

[0216] Among them, the wheel speed signal indicates the wheel speed of the four wheels of the electric vehicle, the yaw rate signal indicates the yaw rate of the electric vehicle, the steering wheel signal indicates the direction and angle of steering wheel rotation, and the pedal signal indicates the opening degree of the brake pedal and the accelerator pedal.

[0217] In one embodiment, the controller may be a central controller.

[0218] In another embodiment, the controller can be a controller used for controlling the electric vehicle's operation on split-level roads. The two can serve as backups for each other, improving the control stability of the electric vehicle.

[0219] In one embodiment, the controller also actively sends a torque signal to the motor controller to control the drive motor to adjust the torque output to the wheels.

[0220] See Figure 13 , ​ A schematic diagram of the operating logic of a controller provided in an embodiment of this application is shown.

[0221] In the controller, firstly, a split-road surface is identified based on the collected signals. Then, the identification result is corrected to avoid misidentifying sharp turning scenarios as split-road surfaces. Simultaneously, an additional yaw moment is calculated. Based on the target torque of each wheel, the additional yaw moment generated by the torque difference between the left and right wheels is calculated, and the additional yaw moment is smoothed.

[0222] Then, based on the corrected identification results and the smoothed additional yaw moment, the steering angles of the front and rear wheels on the high-attached side are calculated, and the steering angle signal and the torque signal are output.

[0223] Among them, the steering angle indicated by the steering angle signal is less than the maximum steering angle limited by the mechanical system.

[0224] In one embodiment, the process of determining the split road surface within the controller may include: calculating the translational velocity of the wheel centers of the four wheels; if the difference between the translational velocity and linear velocity of the left wheel center is greater than a threshold difference, incrementing the first counter by 1; if the difference between the translational velocity and linear velocity of the right wheel center is greater than a threshold difference, incrementing the second counter by 1; if the absolute value of the acceleration or deceleration of the electric vehicle is less than a threshold, or if the opening of the accelerator pedal or brake pedal is less than a preset pedal opening, decrementing the first or second counter by 1; if the count of the first counter exceeds a quantity threshold, determining the road surface as a split road surface with a lower attachment on the left and a higher attachment on the right; if the count of the second counter exceeds a quantity threshold, determining the road surface as a split road surface with a higher attachment on the left and a lower attachment on the right.

[0225] In another embodiment of this application, an electric vehicle is also provided, the electric vehicle including a controller and four wheels, wherein:

[0226] The controller is used to: control the wheel steering of an electric vehicle based on the direction and angle of the steering wheel rotation when the electric vehicle is traveling on a uniform road surface; actively control the wheel steering of the electric vehicle before the steering wheel angle changes when the electric vehicle is traveling straight on a split road surface; and actively control the wheels to return to center after the electric vehicle leaves the split road surface before the steering wheel angle changes. Specifically, when the electric vehicle is traveling on a uniform road surface, the difference in the coefficient of adhesion between the two coaxial wheels and the road surface is less than a preset value; when the electric vehicle is traveling on a split road surface, the difference in the coefficient of adhesion between the two coaxial wheels and the road surface is greater than a preset value.

[0227] 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.

[0228] Finally, it should be noted that the above are merely specific embodiments 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 of an electric vehicle, characterized by, The control method improves the stability of the electric vehicle driving on the split road by actively adjusting the steering angle of the wheels, and the control method comprises: During the process of the electric vehicle driving on the uniform road, the steering of the wheels of the electric vehicle is controlled according to the direction and angle of the steering wheel of the electric vehicle; During the process of the electric vehicle driving straight on the split road, the steering of the wheels of the electric vehicle is actively controlled before the steering angle of the steering wheel changes; After the electric vehicle drives off the split road, the steering of the wheels of the electric vehicle is actively controlled before the steering angle of the steering wheel changes; Wherein, the difference between the adhesion coefficients between the two coaxial wheels of the electric vehicle and the road during the process of the electric vehicle driving on the uniform road is less than a preset value, and the difference between the adhesion coefficients between the two coaxial wheels of the electric vehicle and the road during the process of the electric vehicle driving on the split road is greater than the preset value.

2. The control method according to claim 1, characterized by, The control method specifically comprises: The adhesion coefficients of the two right wheels of the electric vehicle on the split road are greater than the adhesion coefficients of the two left wheels, and during the process of the electric vehicle driving straight on the split road, the steering angle of at least one right wheel of the electric vehicle is actively controlled to be greater than the steering angle of the left wheel coaxial with the at least one right wheel before the steering angle of the steering wheel changes.

3. The control method according to claim 2, characterized by, The control method specifically comprises: During the process of the electric vehicle driving straight on the split road, the steering directions of the two right wheels of the electric vehicle are actively controlled to be different and the steering angles of the two left wheels are zero before the steering angle of the steering wheel changes.

4. The control method according to claim 3, characterized by The control method specifically comprises: During the process of the electric vehicle driving straight on the split road, the right front wheel is actively controlled to steer right and the right rear wheel is actively controlled to steer left before the steering angle of the steering wheel changes when the opening degree of the accelerator pedal is greater than a preset accelerator pedal opening degree.

5. The control method according to claim 3, characterized by, The control method specifically comprises: During the process of the electric vehicle driving straight on the split road, the right front wheel is actively controlled to steer left and the right rear wheel is actively controlled to steer right before the steering angle of the steering wheel changes when the opening degree of the brake pedal is greater than a preset brake pedal opening degree.

6. The control method according to claim 2, characterized by, The control method specifically comprises: During the process of the electric vehicle driving straight on the split road, the two front wheels of the electric vehicle are actively controlled to steer right and the steering angles of the two rear wheels are zero before the steering angle of the steering wheel changes when the opening degree of the accelerator pedal is greater than a preset accelerator pedal opening degree.

7. The control method according to claim 2, characterized by, The control method specifically comprises: During the process of the electric vehicle driving straight on the split road, the two front wheels of the electric vehicle are actively controlled to steer right and the two rear wheels are actively controlled to steer left before the steering angle of the steering wheel changes when the opening degree of the accelerator pedal is greater than a preset accelerator pedal opening degree.

8. The control method according to any one of claims 2 to 7, characterized by, The control method specifically comprises: The greater the difference between the adhesion coefficients of the two right wheels of the electric vehicle on the split road and the adhesion coefficients of the two left wheels, the greater the difference between the steering angle of at least one right wheel of the electric vehicle and the steering angle of the left wheel coaxial with the at least one right wheel.

9. The control method according to claim 1, characterized by, The control method further comprises: In the process that the electric vehicle runs on the uniform road surface, the angle of the steering wheel turning left is a first steering wheel angle, the angle of the right front wheel being actively controlled to turn left is a first front wheel angle, and the angle of the right rear wheel being actively controlled to turn left is a first rear wheel angle; The difference between the adhesion coefficient of the pair of open road surface to the two right wheels of the electric vehicle and the adhesion coefficient to the two left wheels is greater, the difference between the second front wheel angle and the first front wheel angle and the difference between the second rear wheel angle and the first rear wheel angle are greater. The control method specifically comprises:

10. The control method according to claim 9, characterized by When the opening degree of the accelerator pedal is greater than a preset accelerator pedal opening degree, the second front wheel angle is actively controlled to be smaller than the first front wheel angle, and the second rear wheel angle is actively controlled to be greater than the first rear wheel angle. The control method specifically comprises:

11. The control method according to claim 9, characterized by, When the opening degree of the brake pedal is greater than a preset brake pedal opening degree, the second front wheel angle is actively controlled to be greater than the first front wheel angle, and the second rear wheel angle is actively controlled to be smaller than the first rear wheel angle. The control method specifically comprises:

12. The control method according to any one of claims 9-11, characterized by, The difference between the adhesion coefficient of the pair of open road surface to the two right wheels of the electric vehicle and the adhesion coefficient to the two left wheels is greater, the difference between the second front wheel angle and the first front wheel angle and the difference between the second rear wheel angle and the first rear wheel angle are greater. The control method further comprises:

13. The control method according to any one of claims 2 to 7, characterized by, In the process that the electric vehicle runs straight on the pair of open road surface, before the steering angle of the steering wheel changes, the absolute value of the sum of the torques output by the driving system of the electric vehicle to the two right wheels is actively controlled to be greater than the absolute value of the sum of the torques output to the two left wheels. The control method further comprises:

14. The control method according to any one of claims 9-11, characterized by, In the process that the electric vehicle runs straight on the pair of open road surface, before the steering angle of the steering wheel changes, the absolute value of the sum of the torques output by the driving system of the electric vehicle to the two right wheels is actively controlled to be greater than the absolute value of the sum of the torques output to the two left wheels. The control method specifically comprises: The difference between the adhesion coefficient of the pair of open road surface to the two right wheels of the electric vehicle and the adhesion coefficient to the two left wheels is greater, the difference between the second front wheel angle and the first front wheel angle and the difference between the second rear wheel angle and the first rear wheel angle are greater. The controller is used for:

15. The control method according to claim 13 or 14, characterized by, In the process that the electric vehicle runs on the uniform road surface, the steering of the wheels of the electric vehicle is controlled according to the direction and angle of the steering wheel of the electric vehicle; In the process that the electric vehicle runs straight on the pair of open road surface, before the steering angle of the steering wheel changes, the steering of the wheels of the electric vehicle is actively controlled.

16. A controller characterized by comprising: ​ ​ ​ The wheels of the electric vehicle are actively controlled to straighten before the steering angle of the steering wheel changes after the electric vehicle drives away from the road surface with opposite adhesion coefficients. The difference between the adhesion coefficients between the two coaxial wheels and the road surface is less than a preset value when the electric vehicle drives on the uniform road surface, and the difference between the adhesion coefficients between the two coaxial wheels and the road surface is greater than the preset value when the electric vehicle drives on the road surface with opposite adhesion coefficients.

17. An electric vehicle characterized by comprising: The electric vehicle comprises a controller and four wheels, wherein: The controller is used to: The wheels of the electric vehicle are actively controlled to straighten before the steering angle of the steering wheel changes after the electric vehicle drives away from the road surface with opposite adhesion coefficients. The wheels of the electric vehicle are actively controlled to straighten before the steering angle of the steering wheel changes after the electric vehicle drives away from the road surface with opposite adhesion coefficients. The difference between the adhesion coefficients between the two coaxial wheels and the road surface is less than a preset value when the electric vehicle drives on the uniform road surface, and the difference between the adhesion coefficients between the two coaxial wheels and the road surface is greater than the preset value when the electric vehicle drives on the road surface with opposite adhesion coefficients. ​

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