Control method for reducing pitching of electric vehicle, motor controller and electric vehicle

Abstract

The invention provides a control method for reducing pitching of an electric vehicle, a motor controller and the electric vehicle, and is applied to the technical field of electric vehicles, and the control method is used for adjusting torque output by a driving system in the process that the electric vehicle passes through a deceleration strip so as to improve the driving comfort. The output torque is adjusted by actively controlling the front drive motor and the rear drive motor, the backward moving degree of the gravity center of the electric vehicle is adjusted, the sprung mass of the front suspension and the sprung mass of the rear suspension are adjusted, the offset frequency of the wheel ends of the suspensions is rapidly adjusted, and the heights of the front suspension and the rear suspension change at the same frequency (for example, compression and bounce at the same time); the front axle and the rear axle of the electric vehicle are changed at the same frequency, pitching of the electric vehicle is reduced, and the driving comfort is improved in the process that the electric vehicle passes through the deceleration strip. And after the two rear wheels leave the deceleration strip, the front-drive motor and the rear-drive motor are actively controlled to adjust the output torque, the same-frequency change of the front shaft and the rear shaft of the electric vehicle is rapidly controlled, and the pitching of the electric vehicle is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of electric vehicles, and particularly to a control method for reducing the pitch of an electric vehicle, a motor controller, and an electric vehicle. Background Art

[0002] During the driving process of an electric vehicle, when the electric vehicle passes over a speed bump, the wheels in contact with the speed bump will be compressed by the intrusion of the speed bump, and the suspension of the wheel will be compressed. After the suspension is compressed, it will quickly bounce back. This process will cause the body attitude of the electric vehicle to be unstable, affecting the comfort of the user's ride. In addition, the driver may also step on the accelerator pedal or the brake pedal to accelerate or decelerate when passing over the speed bump. During this process, the body attitude of the electric vehicle is even more unstable, and the electric vehicle is also prone to move forward and backward, further affecting the ride comfort. After the electric vehicle leaves the speed bump, the front and rear pitch of the electric vehicle will not disappear immediately and will continue to affect the ride comfort. Summary of the Invention

[0003] Embodiments of the present application provide a control method for reducing the pitch of an electric vehicle, a motor controller, and an electric vehicle. By actively controlling the drive system to adjust the torque output to adjust the attitudes of the front suspension and the rear suspension, it is realized that during the process of the electric vehicle passing over a speed bump, the changes of the front axle and the rear axle are quickly controlled to be in the same frequency, reducing the pitch of the electric vehicle and improving the ride comfort.

[0004] In a first aspect, embodiments of the present application provide a control method for reducing the pitch of an electric vehicle. The control method is used to adjust the torque output by the drive system during the process of the electric vehicle accelerating over a speed bump to improve the ride comfort. Before the two front wheels of the electric vehicle contact the speed bump, the torque output by the front drive motor of the electric vehicle to the two front wheels and the torque output by the rear drive motor of the electric vehicle to the two rear wheels are controlled according to the opening of the accelerator pedal; during the process of the electric vehicle passing over the speed bump, the front drive motor and the rear drive motor are actively controlled to adjust the output torque; after the two rear wheels of the electric vehicle leave the speed bump, the torque output by the drive motor corresponding to the suspension with a higher height in the front suspension and the rear suspension of the electric vehicle is actively controlled to be greater than the torque output by the drive motor corresponding to the suspension with a lower height in the front suspension and the rear suspension.

[0005] In this embodiment, before the two front wheels of the electric vehicle come into contact with the speed bump, by controlling the torques output by the front drive motor and the rear drive motor according to the opening degree of the accelerator pedal, the electric vehicle can accelerate at the acceleration expected by the user. During the process of the electric vehicle passing over the speed bump, by actively controlling the front drive motor and the rear drive motor to adjust the output torques, adjusting the degree of the center of gravity of the electric vehicle moving backward, and adjusting the unsprung masses of the front suspension and the rear suspension, the rapid adjustment of the wheel-end natural frequency of the suspension is achieved, so that the heights of the front suspension and the rear suspension change in the same frequency (for example, compressing simultaneously and bouncing simultaneously), the front axle and the rear axle of the electric vehicle change in the same frequency, the pitching of the electric vehicle is reduced, and the riding comfort is improved during the process of the electric vehicle passing over the speed bump. After the two rear wheels of the electric vehicle leave the speed bump, by actively controlling the torque output by the drive motor corresponding to the suspension with a larger height in the front suspension and the rear suspension of the electric vehicle to be greater than the torque output by the drive motor corresponding to the suspension with a smaller height in the front suspension and the rear suspension, adjusting the unsprung masses of the front suspension and the rear suspension, quickly controlling the heights of the front suspension and the rear suspension to change in the same frequency after the two rear wheels leave the speed bump, the front axle and the rear axle of the electric vehicle change in the same frequency, the pitching of the electric vehicle is reduced, and the riding comfort is improved.

[0006] In an embodiment of the first aspect, after the first moment when the two front wheels come into contact with the speed bump and before the second moment when the two front wheels reach the highest point of the speed bump, control both the front drive motor and the rear drive motor to output the torques indicated by the torque signals; after the second moment and before the third moment when the two front wheels leave the speed bump, actively control the torque output by the front drive motor to decrease and the torque output by the rear drive motor to increase.

[0007] In this embodiment, during the process of the electric vehicle accelerating over the speed bump, after the second moment when the two front wheels reach the highest point of the speed bump and before the third moment when the two front wheels leave the speed bump, by actively controlling the torque output by the front drive motor to decrease and the torque output by the rear drive motor to increase, it is possible to adjust the increase of the unsprung mass of the front suspension and the decrease of the unsprung mass of the rear suspension, so that the heights of the front suspension and the rear suspension increase in the same frequency, the front axle and the rear axle of the electric vehicle change in the same frequency, thereby reducing the pitching of the electric vehicle and improving the riding comfort. At the same time, the wheel-end natural frequency of the front suspension is reduced, so that the vibration response of the vehicle body when the front wheels pass over the speed bump will be slow, further improving the riding comfort.

[0008] In an embodiment of the first aspect, after the third moment and before the fourth moment when the front suspension bounces, actively control the torque output by the front drive motor to increase and the torque output by the rear drive motor to decrease.

[0009] In this embodiment, during the process of an electric vehicle accelerating over a speed bump, after the third moment when the two front wheels leave the speed bump and before the fourth moment when the front suspension rebounds, by actively controlling the increase in the torque output by the front drive motor and the decrease in the torque output by the rear drive motor, it is possible to adjust the reduction of the unsprung mass of the front suspension and the increase of the unsprung mass of the rear suspension, so that the heights of the front suspension and the rear suspension decrease in the same frequency, and the front axle and the rear axle of the electric vehicle change in the same frequency, thereby reducing the pitch of the electric vehicle and improving the riding comfort.

[0010] In an embodiment of the first aspect, after the fifth moment when the two rear wheels contact the speed bump and before the sixth moment when the two rear wheels reach the highest point of the speed bump, control both the front drive motor and the rear drive motor to output the torque indicated by the torque signal; after the sixth moment and before the seventh moment when the two rear wheels leave the speed bump, actively control the increase in the torque output by the front drive motor and the decrease in the torque output by the rear drive motor.

[0011] In this embodiment, during the process of an electric vehicle accelerating over a speed bump, after the fifth moment when the two rear wheels contact the speed bump and before the sixth moment when the two rear wheels reach the highest point of the speed bump, by controlling both the front drive motor and the rear drive motor to output the torque indicated by the torque signal, the electric vehicle can accelerate at the acceleration desired by the user. After the sixth moment when the two rear wheels reach the highest point of the speed bump and before the seventh moment when the two rear wheels leave the speed bump, by actively controlling the increase in the torque output by the front drive motor and the decrease in the torque output by the rear drive motor, it is possible to adjust the reduction of the unsprung mass of the front suspension and the increase of the unsprung mass of the rear suspension, so that the heights of the front suspension and the rear suspension increase in the same frequency, and the front axle and the rear axle of the electric vehicle change in the same frequency, thereby reducing the pitch of the electric vehicle and improving the riding comfort. At the same time, the wheel-end natural frequency of the rear suspension is reduced, so that the vibration response of the vehicle body when the rear wheels pass over the speed bump will be slow, further improving the riding comfort.

[0012] In an embodiment of the first aspect, actively control the difference between the torque output by the drive motor corresponding to the suspension with a larger height in the front suspension and the rear suspension and the torque output by the drive motor corresponding to the suspension with a smaller height in the front suspension and the rear suspension to increase as the height difference between the front suspension and the rear suspension increases.

[0013] In this embodiment, the greater the height difference between the front suspension and the rear suspension, the greater the difference in the unsprung mass between the front suspension and the rear suspension, and the greater the pitch of the electric vehicle. By actively controlling the difference between the torque output by the drive motor corresponding to the suspension with a greater height in the front suspension and the rear suspension and the torque output by the drive motor corresponding to the suspension with a smaller height in the front suspension and the rear suspension, which increases as the height difference between the front suspension and the rear suspension increases, it is possible to flexibly adjust the torques output by the front drive motor and the rear drive motor when the height differences between the front suspension and the rear suspension are different, so as to adjust the unsprung mass of the front suspension and the rear suspension, achieve rapid control of the synchronous change in the heights of the front suspension and the rear suspension, reduce the pitch of the electric vehicle, and improve the riding comfort.

[0014] In an embodiment of the first aspect, the fifth moment and the sixth moment are predicted based on the first moment, the second moment, the vehicle speed of the electric vehicle, the acceleration of the electric vehicle, and the distance between the front wheels and the rear wheels of the electric vehicle.

[0015] In this embodiment, by obtaining relevant information when the two front wheels pass over a speed bump, the moments when the drive motor torques need to be adjusted when the two rear wheels pass over the speed bump are predicted, which is beneficial for subsequent feedforward control of the torque output of the drive motor when the two rear wheels pass over the speed bump based on the torque output data of the drive motor when the two front wheels pass over the speed bump, and is beneficial for better controlling the overall vehicle attitude during the process of the electric vehicle passing over the speed bump and enhancing the riding experience.

[0016] In an embodiment of the first aspect, after the second moment and before the third moment, actively control the torque output by the front drive motor to the two front wheels to be less than the torque indicated by the torque signal and the torque output by the rear drive motor to the two rear wheels to be greater than the torque indicated by the torque signal; after the sixth moment and before the seventh moment, actively control the torque output by the front drive motor to the two front wheels to be greater than the torque indicated by the torque signal and the torque output by the rear drive motor to the two rear wheels to be less than the torque indicated by the torque signal.

[0017] In this embodiment, during the process of the electric vehicle accelerating over a speed bump, by actively controlling the torque output by the front drive motor to the two front wheels to be less than the torque indicated by the torque signal and the torque output by the rear drive motor to the two rear wheels to be greater than the torque indicated by the torque signal, and actively controlling the torque output by the front drive motor to the two front wheels to be greater than the torque indicated by the torque signal and the torque output by the rear drive motor to the two rear wheels to be less than the torque indicated by the torque signal, rather than not adjusting the torque output of the drive motor and waiting for the suspension system to buffer the bumps, the riding comfort is improved.

[0018] In an embodiment of the first aspect, the difference between the decrease in the torque output by the front drive motor to the two front wheels and the increase in the torque output by the rear drive motor to the two rear wheels is less than a preset difference; the difference between the increase in the torque output by the front drive motor to the two front wheels and the decrease in the torque output by the rear drive motor to the two rear wheels is less than a preset difference.

[0019] Wherein, the preset difference is a relatively small value, such as 3, 5, 8, etc. If the difference between the decrease in the torque output by the drive motor to the two front wheels and the increase in the torque output by the drive motor to the two rear wheels is less than the preset difference, it is considered that the decrease in the torque output by the drive motor to the two front wheels and the increase in the torque output by the drive motor to the two rear wheels are almost the same.

[0020] In this embodiment, during the process of the electric vehicle accelerating over a speed bump, by actively controlling the difference between the decrease in the torque output by the front drive motor to the two front wheels and the increase in the torque output by the rear drive motor to the two rear wheels to be less than the preset difference; actively controlling the difference between the increase in the torque output by the front drive motor to the two front wheels and the decrease in the torque output by the rear drive motor to the two rear wheels to be less than the preset difference, it is realized that the total torque output by the drive motor to the electric vehicle remains unchanged, and the overall acceleration of the electric vehicle is stable, so that the vehicle front and rear axles are adjusted in the same frequency without the user's perception, improving the driving and riding experience.

[0021] In an embodiment of the first aspect, the height of the suspension of the four wheels is determined according to the height indicated by the height signals from the wheel height sensors of the four wheels and / or the acceleration indicated by the acceleration signals of the acceleration sensors in the vertical direction.

[0022] In this embodiment, both the height signals of the wheel height sensors and the acceleration signals of the acceleration sensors in the vertical direction are signals that can be directly obtained. According to the height signals and the acceleration signals, the height of the suspension of the wheels can be accurately determined, thereby improving the accuracy of subsequent control.

[0023] Second aspect, an embodiment of the present application provides a control method for reducing the pitch of an electric vehicle. The control method is used to adjust the torque output by the drive system during the process of the electric vehicle braking through a speed bump to improve the ride comfort. Before the two front wheels of the electric vehicle touch the speed bump, the reverse torque output by the front drive motor of the electric vehicle to the two front wheels and the reverse torque output by the rear drive motor of the electric vehicle to the two rear wheels are controlled according to the opening of the brake pedal; the direction of the reverse torque is opposite to the direction of wheel rotation; during the process of the electric vehicle passing through the speed bump, the front drive motor and the rear drive motor are actively controlled to adjust the output reverse torque; after the two rear wheels of the electric vehicle leave the speed bump, the reverse torque output by the drive motor corresponding to the suspension with a higher height in the front suspension and the rear suspension of the electric vehicle is actively controlled to be greater than the reverse torque output by the drive motor corresponding to the suspension with a lower height in the front suspension and the rear suspension.

[0024] In this embodiment, before the two front wheels of the electric vehicle touch the speed bump, by controlling the reverse torque output by the front drive motor and the rear drive motor according to the opening of the brake pedal, the electric vehicle can decelerate at a deceleration desired by the user. During the process of the electric vehicle passing through the speed bump, by actively controlling the front drive motor and the rear drive motor to adjust the output reverse torque, the degree of the center of gravity of the electric vehicle moving forward is adjusted, the unsprung mass of the front suspension and the rear suspension is adjusted, and the rapid adjustment of the wheel-end natural frequency of the suspension is realized, so that the heights of the front suspension and the rear suspension are controlled to change in the same frequency, the front axle and the rear axle of the electric vehicle change in the same frequency, the pitch of the electric vehicle is reduced, and the ride comfort is improved during the process of the electric vehicle passing through the speed bump. After the two rear wheels of the electric vehicle leave the speed bump, by actively controlling the torque output by the drive motor corresponding to the suspension with a higher height in the front suspension and the rear suspension of the electric vehicle to be greater than the torque output by the drive motor corresponding to the suspension with a lower height in the front suspension and the rear suspension, the unsprung mass of the front suspension and the rear suspension is adjusted, and the heights of the front suspension and the rear suspension are quickly controlled to change in the same frequency after the two rear wheels leave the speed bump, the front axle and the rear axle of the electric vehicle change in the same frequency, the pitch of the electric vehicle is reduced, and the ride comfort is improved.

[0025] In an embodiment of the second aspect, after the first moment when the two front wheels touch the speed bump and before the second moment when the two front wheels reach the highest point of the speed bump, the front drive motor and the rear drive motor are controlled to output the reverse torque indicated by the torque signal; after the second moment and before the third moment when the two front wheels leave the speed bump, the reverse torque output by the front drive motor is actively controlled to increase and the reverse torque output by the rear drive motor is actively controlled to decrease.

[0026] In this embodiment, during the process of an electric vehicle braking through a speed bump, after the first moment when the two front wheels contact the speed bump and before the second moment when the two front wheels reach the highest point of the speed bump, by controlling both the front drive motor and the rear drive motor to output reverse torques indicated by torque signals, the electric vehicle can decelerate and travel at a deceleration desired by the user. After the second moment when the two front wheels reach the highest point of the speed bump and before the third moment when the two front wheels leave the speed bump, by actively controlling the reverse torque output by the front drive motor to increase and the reverse torque output by the rear drive motor to decrease, it is possible to adjust the increase in the unsprung mass of the front suspension and the decrease in the unsprung mass of the rear suspension, so that the heights of the front suspension and the rear suspension increase in the same frequency, and the front axle and the rear axle of the electric vehicle change in the same frequency, thereby reducing the pitch of the electric vehicle and improving the riding comfort. At the same time, the wheel-end natural frequency of the front suspension is reduced, so that the vibration response of the vehicle body when the front wheels pass over the speed bump is slow, further improving the riding comfort.

[0027] In an embodiment of the second aspect, after the third moment and before the fourth moment when the front suspension rebounds, actively control the reverse torque output by the front drive motor to decrease and the reverse torque output by the rear drive motor to increase.

[0028] In this embodiment, during the process of an electric vehicle braking through a speed bump, after the third moment when the two front wheels leave the speed bump and before the fourth moment when the front suspension rebounds, by actively controlling the reverse torque output by the front drive motor to decrease and the reverse torque output by the rear drive motor to increase, it is possible to adjust the decrease in the unsprung mass of the front suspension and the increase in the unsprung mass of the rear suspension, so that the heights of the front suspension and the rear suspension decrease in the same frequency, and the front axle and the rear axle of the electric vehicle change in the same frequency, thereby reducing the pitch of the electric vehicle and improving the riding comfort.

[0029] In an embodiment of the second aspect, after the fifth moment when the two rear wheels contact the speed bump and before the sixth moment when the two rear wheels reach the highest point of the speed bump, control both the front drive motor and the rear drive motor to output reverse torques indicated by torque signals; after the sixth moment and before the seventh moment when the two rear wheels leave the speed bump, actively control the reverse torque output by the front drive motor to decrease and the reverse torque output by the rear drive motor to increase.

[0030] In this embodiment, during the process of an electric vehicle braking over a speed bump, after the fifth moment when the two rear wheels contact the speed bump and before the sixth moment when the two rear wheels reach the highest point of the speed bump, by controlling both the front drive motor and the rear drive motor to output the reverse torque indicated by the torque signal, the electric vehicle can decelerate at a deceleration desired by the user. After the sixth moment when the two rear wheels reach the highest point of the speed bump and before the seventh moment when the two rear wheels leave the speed bump, by actively controlling the reduction of the reverse torque output by the front drive motor and the increase of the reverse torque output by the rear drive motor, it is possible to adjust the reduction of the unsprung mass of the front suspension and the increase of the unsprung mass of the rear suspension, so that the heights of the front suspension and the rear suspension increase in the same frequency, and the front axle and the rear axle of the electric vehicle change in the same frequency, thereby reducing the pitch of the electric vehicle and improving the ride experience. The ride comfort is improved. At the same time, the wheel-end partial frequency of the rear suspension is reduced, so that the vibration response of the vehicle body when the rear wheels pass over the speed bump is slow, further improving the ride comfort.

[0031] In an embodiment of the second aspect, the difference between the reverse torque output by the drive motor corresponding to the suspension with a larger height in the front suspension and the rear suspension and the reverse torque output by the drive motor corresponding to the suspension with a smaller height in the front suspension and the rear suspension is actively controlled to increase as the height difference between the front suspension and the rear suspension increases.

[0032] In this embodiment, the larger the height difference between the front suspension and the rear suspension, the greater the difference in the unsprung mass between the front suspension and the rear suspension, and the greater the pitch of the electric vehicle. By actively controlling the difference between the reverse torque output by the drive motor corresponding to the suspension with a larger height in the front suspension and the rear suspension and the reverse torque output by the drive motor corresponding to the suspension with a smaller height in the front suspension and the rear suspension to increase as the height difference between the front suspension and the rear suspension increases, it is possible to flexibly adjust the reverse torque output by the front drive motor and the rear drive motor when the height differences between the front suspension and the rear suspension are different, so as to adjust the unsprung mass of the front suspension and the rear suspension, realize the rapid control of the same-frequency change of the heights of the front suspension and the rear suspension, reduce the pitch of the electric vehicle, and improve the ride comfort.

[0033] In an embodiment of the second aspect, after the second moment and before the third moment, actively control the reverse torque output by the front drive motor to the two front wheels to be less than the reverse torque indicated by the torque signal and the reverse torque output by the rear drive motor to the two rear wheels to be less than the reverse torque indicated by the torque signal; after the sixth moment and before the seventh moment, actively control the reverse torque output by the front drive motor to the two front wheels to be greater than the reverse torque indicated by the torque signal and the reverse torque output by the rear drive motor to the two rear wheels to be greater than the reverse torque indicated by the torque signal.

[0034] In this embodiment, during the process of an electric vehicle braking through a speed bump, by actively controlling the reverse torque output by the front-wheel drive motor to the two front wheels to be less than the reverse torque indicated by the torque signal and the reverse torque output by the rear-wheel drive motor to the two rear wheels to be less than the reverse torque indicated by the torque signal, and by actively controlling the reverse torque output by the front-wheel drive motor to the two front wheels to be greater than the reverse torque indicated by the torque signal and the reverse torque output by the rear-wheel drive motor to the two rear wheels to be greater than the reverse torque indicated by the torque signal, rather than not adjusting the reverse torque output of the drive motor or the braking force output of the braking system and waiting for the suspension system to buffer the bumps, the riding comfort is improved.

[0035] In an embodiment of the second aspect, the difference between the decrease amount of the reverse torque output by the front-wheel drive motor to the two front wheels actively controlled and the increase amount of the reverse torque output by the rear-wheel drive motor to the two rear wheels is less than a preset difference; the difference between the increase amount of the reverse torque output by the front-wheel drive motor to the two front wheels actively controlled and the decrease amount of the reverse torque output by the rear-wheel drive motor to the two rear wheels is less than a preset difference.

[0036] In this embodiment, during the process of an electric vehicle braking through a speed bump, by actively controlling the difference between the decrease amount of the reverse torque output by the front-wheel drive motor to the two front wheels and the increase amount of the reverse torque output by the rear-wheel drive motor to the two rear wheels to be less than a preset difference; the difference between the increase amount of the reverse torque output by the front-wheel drive motor to the two front wheels and the decrease amount of the reverse torque output by the rear-wheel drive motor to the two rear wheels is less than a preset difference, it is achieved that the total reverse torque output by the drive motor to the electric vehicle remains unchanged, and the overall deceleration of the electric vehicle is stable, so that the vehicle front and rear axles are adjusted in the same frequency without the user's perception, and the riding experience is improved.

[0037] In the third aspect, an embodiment of the present application provides a motor controller, and the motor controller is used to execute the vehicle control method in any implementation manner of the first aspect and / or the second aspect.

[0038] In the fourth aspect, an embodiment of the present application provides an electric vehicle, and this electric vehicle includes the motor controller, the drive system, and the braking system as described in the third aspect. The motor controller is used to control the drive motor to output torque or reverse torque to the wheels of the electric vehicle, and is also used to control the braking system to output braking force to the four wheels of the electric vehicle.

[0039] For the supplements and technical effects of the solutions provided in the above third aspect and fourth aspect, reference may be made to the corresponding descriptions in the first aspect and the second aspect, and details will not be repeated. Description of the Drawings

[0040] Figure 1 A schematic diagram showing the height of the suspension of the four wheels of an electric vehicle is shown;

[0041] Figure 2 Shows a schematic diagram of an electric vehicle 100 provided by an embodiment of the present application;

[0042] Figure 3 Shows a schematic diagram of the architecture of an electric vehicle 100 provided by an embodiment of the present application;

[0043] Figure 4 Shows a schematic diagram of a driving scenario of an electric vehicle 100 provided by an embodiment of the present application;

[0044] Figure 5 Shows a schematic diagram of a control method of an electric vehicle 100 provided by an embodiment of the present application;

[0045] Figure 6 Shows a schematic diagram of a control method of an electric vehicle 100 provided by an embodiment of the present application;

[0046] Figure 7 Shows a schematic diagram of a motor controller provided by an embodiment of the present application. Detailed implementation manners

[0047] Next, the technical solutions in the embodiments of the present application will be described with reference to the accompanying drawings.

[0048] In the embodiments of the present application, prefix words such as "first" and "second" are only used to distinguish different described objects, and have no limiting effect on the position, order, priority, quantity, content, etc. of the described objects. The use of ordinal numbers and other prefix words for distinguishing described objects in the embodiments of the present application does not constitute a limitation on the described objects. The statements of the described objects refer to the descriptions in the context of the claims or embodiments, and should not constitute unnecessary limitations because of the use of such prefix words.

[0049] During the driving process of an electric vehicle, when the electric vehicle passes over a speed bump, the wheel in contact with the speed bump will be invaded and compressed by the speed bump, and the suspension of this wheel will be compressed. After the suspension is compressed, it will quickly bounce back. This process will cause the body attitude of the electric vehicle to be unstable, affecting the comfort of the user's ride. Also, the driver may step on the accelerator pedal or the brake pedal to accelerate or decelerate when passing over the speed bump. During this process, the body attitude of the electric vehicle is even more unstable, and the electric vehicle is also prone to move forward and backward, further affecting the comfort of the ride. After the electric vehicle leaves the speed bump, the front and rear pitching of the electric vehicle will not disappear immediately, and will continue to affect the comfort of the ride.

[0050] In one implementation, a combination of a shock absorber (e.g., a Continuous Damping Control (CDC)) and an air spring can be used to achieve support, buffering, and energy absorption of an electric vehicle in response to bumpy scenarios, so as to reduce the jolts of the electric vehicle when passing over a speed bump. As an example, during the process of the electric vehicle passing over a speed bump, the CDC identifies the state of the electric vehicle through four wheel height sensors and an acceleration sensor in the vertical direction, and through continuous adjustment of the damping, enables the electric vehicle to better absorb road impacts when passing over a speed bump. The air spring, on the other hand, acts more as a passive component, providing different vehicle body heights and spring stiffnesses at different vehicle speeds for bump buffering.

[0051] However, during the process of the electric vehicle passing over a speed bump, for the combination of the CDC and the air spring, it is generally hoped that the user can reduce the vehicle speed when passing over the speed bump, giving the suspension more time for undulating motion to reduce the impact on the ride experience, and the applicable range is limited. Also, when accelerating or braking while passing over the speed bump, the combination of the CDC and the air spring will make the vehicle body attitude more uncertain, and still easily cause the instability of the electric vehicle body attitude, affecting the ride experience.

[0052] According to the analysis, please refer to Figure 1 , Figure 1 shows a schematic diagram of the heights of the front suspension and the rear suspension of an electric vehicle. During the process of the electric vehicle driving over a speed bump, as Figure 1 shown, the following process occurs to the electric vehicle: The wheels in contact with the speed bump (e.g., two front wheels) are compressed by the intrusion of the speed bump, the height of the suspension of this wheel decreases, the suspension rebounds after compression, and the height of the suspension increases. During this process, the height of the suspension of the wheels not in contact with the speed bump (e.g., two rear wheels) remains unchanged, causing the height changes on the side of the wheels in contact with the speed bump (e.g., the front axle) and the side of the wheels not in contact with the speed bump (e.g., the rear axle) to be out of sync, thereby causing the electric vehicle to pitch forward and backward, further leading to the instability of the electric vehicle body attitude and the electric vehicle to move forward and backward erratically. And Figure 1 after the electric vehicle leaves the speed bump, the front suspension and the rear suspension still compress and rebound and the height changes of the front suspension and the rear suspension are out of sync (e.g., not compressing simultaneously, not rebounding simultaneously), which will also cause the electric vehicle to pitch forward and backward, affecting the ride comfort.

[0053] In view of this, the embodiments of the present application provide a control method, a motor controller, and an electric vehicle for reducing the pitch of an electric vehicle. By actively controlling the drive system to adjust the torque output to adjust the attitudes of the front suspension and the rear suspension, it is realized that during the process of the electric vehicle passing over a speed bump, the changes of the front axle and the rear axle are quickly controlled to be in sync, reducing the pitch of the electric vehicle and improving the ride comfort.

[0054] See Figure 2, Figure 2 shows a schematic diagram of an electric vehicle 100 provided by an embodiment of the present application. As Figure 2 shown, the electric vehicle 100 includes a drive system 110, a power battery 120 connected to the drive system 110, and a vehicle controller 130. Among them, the drive system 110 is used to drive the electric vehicle 100. The power battery 120 is used to supply electrical energy to the drive system 110. The drive system 110 is used to receive power supply from the power battery 120 and provide power for the electric vehicle 100. Among them, the drive system 110 can also be referred to as a powertrain.

[0055] Optionally, the electric vehicle 100 further includes a braking system 140, and the braking system 140 is used to provide braking force for the electric vehicle 100 when the electric vehicle 100 is in a braking state.

[0056] According to the position of the wheels in the electric vehicle 100, they can be divided into a left front wheel FL, a right front wheel FR, a left rear wheel BL, and a right rear wheel BR. Divided by the axle, the left front wheel and the right front wheel among the four wheels are coaxial and connected by the front axle. The left rear wheel and the right rear wheel are coaxial and connected by the rear axle. Divided by position, the left front wheel and the left rear wheel among the four wheels are on the same side, located on the left side, and the right front wheel and the right rear wheel are on the same side, located on the right side. That is to say, among the four wheels of the electric vehicle 100, the left front wheel and the right front wheel are coaxial wheels with each other, and the left rear wheel and the right rear wheel are coaxial wheels with each other; the left front wheel and the left rear wheel are same-side wheels with each other, and the right front wheel and the right rear wheel are same-side wheels with each other.

[0057] The electric vehicle 100 in the embodiment of the present application can specifically be any one of different types of vehicles such as a sedan, a truck, a passenger bus, etc., and can also be a tricycle, a two-wheeler, a train and other transportation devices for carrying people or goods, or other types of transportation means driven by a power battery. The embodiment of the present application does not make any limitations in this regard. Among them, the vehicle includes but is not limited to pure electric vehicles (pure electric vehicle / battery electric vehicle, pure EV / battery EV), hybrid electric vehicles (hybrid electric vehicle, HEV), range extended electric vehicles (range extended electric vehicle, REEV), plug-in hybrid electric vehicles (plug-in hybrid electric vehicle, PHEV), new energy vehicles (new energy vehicle, NEV), etc.

[0058] The embodiments of the present application do not limit the specific type of the powertrain. By way of example and not limitation, the above powertrain may be a centralized powertrain, or a wheel hub motor powertrain or a wheel side motor powertrain. Among them, the wheel hub motor powertrain directly sets the motor and the reducer in the wheel rim, canceling transmission components such as the half shaft, universal joint, differential, and transmission; the wheel side motor powertrain sets the motor on the subframe.

[0059] The power battery 120 in the embodiments of the present application may be a lithium-ion battery, a lithium metal battery, a lead-acid battery, a nickel-cadmium battery, a nickel-metal hydride battery, a lithium-sulfur battery, a lithium-air battery, or a sodium-ion battery, etc., and the present application does not limit this. In terms of scale, the power battery 120 in the embodiments of the present application may be a single battery cell, or a battery module or a battery pack, and the present application does not limit this. The power battery 120 can also supply power to other electrical appliances in the vehicle, such as the in-vehicle air conditioner, the in-vehicle player, etc.

[0060] Figure 3 The schematic diagram of the architecture of the electric vehicle 100 provided by the embodiments of the present application is shown.

[0061] See Figure 3 In (a) thereof, the electric vehicle 100 is a two-wheel drive model. The drive system 110 includes drive motors 111 of two front wheels and motor controllers 121 of the drive motors 111, and drive motors 112 of two rear wheels and motor controllers 122 of the drive motors 112.

[0062] Among them, each drive motor in the drive system 110 is used to provide driving force for the electric vehicle 100. Specifically, when the electric vehicle 100 is in the driving state, the motor controller of each drive motor receives a torque signal, and receives electric energy from the power battery 120 and controls the corresponding drive motor to output the torque indicated by the torque signal.

[0063] When the electric vehicle 100 is in the driving state, each drive motor in the drive system 110 is used to provide driving force for the electric vehicle 100. Specifically, when the electric vehicle 100 is in the driving state, the vehicle controller 130 calculates the torque demand of the electric vehicle and outputs a torque signal to the motor controller of each drive motor. Each motor controller receives electric energy from the power battery 120 (as Figure 2 shown) and controls the corresponding drive motor to output the torque indicated by the torque signal.

[0064] Continue to refer to Figure 3 In (a) thereof, the braking system 140 mainly includes a brake pedal ( Figure 3(not shown in (a)), a brake controller 141, and four wheel-end brake devices 142. Among them, the brake controller 141 can generate a brake signal based on the opening of the brake pedal, and control one or more of the four wheel-end brake devices 142 to output braking force to the corresponding wheels based on the indication of the brake signal, so as to prevent the wheels from rotating or prevent the rotation tendency of the wheels.

[0065] During the braking process of the electric vehicle 100, the greater the braking force indicated by the brake signal, the greater the braking force output by the wheel-end brake device 142, and the faster the vehicle speed of the electric vehicle 100 decreases.

[0066] When the electric vehicle 100 is in a braking state, the drive system 110 stops driving the wheels to rotate, and the braking system 140 provides braking force for the wheels so that the electric vehicle 100 reduces its speed under the action of the braking force. In the braking state of the electric vehicle 100, each drive motor in the electric vehicle 100 with an 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 vehicle controller 130 receives the brake signal and sends an energy recovery command to each motor controller. Each motor controller controls the corresponding drive motor to operate in a generating state in response to the energy recovery command. Each drive motor converts the kinetic energy of the wheels of the electric vehicle into electrical energy and outputs a reverse torque to the wheels of the electric vehicle 100 to provide braking force for the electric vehicle 100.

[0067] The brake in the braking system 140 in the embodiments of the present application can be an electronic hydraulic brake (EHB) or an electronic mechanical brake (EMB) or other types of brakes, without limitation.

[0068] Among them, the drive system 110, the braking system 140, and the vehicle controller 130 are communicatively connected through a CAN network, and the embodiments of the present application do not limit the specific communication connection method. For example, the motor controller in the drive system 110 and the vehicle controller 130 can communicate through a private CAN network, the brake controller 141 of the braking system 140 and the vehicle controller 130 can communicate through a public CAN network, and the brake controller 141 and each wheel-end brake device 142 can communicate through another private CAN network. Another example is that the vehicle controller 130 can communicate with the motor controller in the drive system 110 and the brake controller 141 in the braking system 140 through the same CAN network.

[0069] See Figure 3In (b) of [description], the electric vehicle 100 is a four-wheel drive model. The drive system 110 includes a drive motor 113 for the left front wheel and a motor controller 123 for the drive motor 113, a drive motor 114 for the right front wheel and a motor controller 124 for the drive motor 114, a drive motor 115 for the left rear wheel and a motor controller 125 for the drive motor 115, and a drive motor 116 for the right rear wheel and a motor controller 126 for the drive motor 116.

[0070] The architecture of the embodiments of the present application has been described above. The following describes the control method for reducing the pitch of an electric vehicle provided by the present application in combination with specific embodiments.

[0071] A control method for reducing the pitch of an electric vehicle provided by an embodiment of the present application can be used to adjust the torque output by the drive system during the process of an electric vehicle accelerating or decelerating through a speed bump to improve the ride comfort.

[0072] Among them, the method provided by the embodiments of the present application is also applicable to scenarios such as when an electric vehicle accelerates or decelerates through bumps caused by damaged road structures, bumps left over from construction, etc.

[0073] The following describes the control method for reducing the pitch of an electric vehicle provided by an embodiment of the present application during the process of an electric vehicle accelerating through a speed bump.

[0074] The control method for reducing the pitch of an electric vehicle provided by an embodiment of the present application includes the following steps.

[0075] Before the two front wheels of the electric vehicle touch the speed bump, control the torque output by the front drive motor of the electric vehicle to the two front wheels and the torque output by the rear drive motor of the electric vehicle to the two rear wheels according to the opening of the accelerator pedal.

[0076] Among them, the front drive motor refers to the drive motors of the two front wheels, and the rear drive motor refers to the drive motors of the two rear wheels.

[0077] Before the two front wheels touch the speed bump, control the front drive motor to output the torque indicated by the opening of the accelerator pedal to the two front wheels and the rear drive motor to output the torque indicated by the opening of the accelerator pedal to the two rear wheels.

[0078] By controlling the torque output by the front drive motor and the rear drive motor according to the opening of the accelerator pedal, the electric vehicle can accelerate at the acceleration expected by the user.

[0079] For easy understanding, please refer to Figure 4 and Figure 5 , Figure 4 shows a schematic diagram of a driving scenario of an electric vehicle 100, Figure 5 shows a schematic diagram of a control method of an electric vehicle 100, Figure 5Take the case where the opening of the accelerator pedal remains unchanged.

[0080] As Figure 4 shown, before the first moment t1, the electric vehicle travels to position 1, and the four wheels do not contact the speed bump.

[0081] Correspondingly, as Figure 5 shown, before the first moment t1, the heights of the front suspension and the rear suspension have not changed. In response to the opening of the accelerator pedal, the front drive motor controls the torque output to the two front wheels, and the rear drive motor of the electric vehicle controls the torque output to the two rear wheels.

[0082] During the process of the electric vehicle passing over the speed bump, actively control the front drive motor and the rear drive motor to adjust the output torque.

[0083] During the process of the electric vehicle passing over the speed bump, actively controlling the front drive motor and the rear drive motor to adjust the output torque includes: actively controlling the output torque of the front drive motor to increase or decrease and actively controlling the rear drive motor to adjust the output torque to increase or decrease.

[0084] As Figure 4 shown, during the process of the electric vehicle passing over the speed bump, the positional relationship between the electric vehicle and the speed bump includes: the electric vehicle travels to position 2, and the two front wheels contact the speed bump; the electric vehicle travels to position 3, and the two front wheels pass over the highest point of the speed bump; the electric vehicle travels to position 4, and the two front wheels leave the speed bump and contact the road surface; the electric vehicle travels to position 5, and the two rear wheels contact the speed bump; the electric vehicle travels to position 6, and the two rear wheels pass over the highest point of the speed bump; the electric vehicle travels to position 7, and the two rear wheels leave the speed bump and contact the road surface.

[0085] When the electric vehicle accelerates, the center of gravity of the electric vehicle moves backward. The unsprung mass of the front suspension is small, and the unsprung mass of the rear suspension is large.

[0086] By actively controlling the front drive motor and the rear drive motor to adjust the output torque, adjusting the degree of the center of gravity of the electric vehicle moving backward, adjusting the unsprung mass of the front suspension and the rear suspension, realizing a rapid adjustment of the wheel-end natural frequency of the suspension, enabling the heights of the front suspension and the rear suspension to change in the same frequency (for example, compressing and rebounding simultaneously), and the front axle and the rear axle of the electric vehicle to change in the same frequency, reducing the pitch of the electric vehicle, and improving the ride comfort during the process of the electric vehicle passing over the speed bump.

[0087] Among them, the wheel-end natural frequency of the suspension refers to the frequency of the wheel vibrating vertically relative to the vehicle body in the suspension system, reflecting the speed of the wheel vibrating in the vertical direction.

[0088] After the two rear wheels of the electric vehicle leave the speed bump, actively control the torque output by the drive motor corresponding to the suspension with a greater height in the front suspension and the rear suspension of the electric vehicle to be greater than the torque output by the drive motor corresponding to the suspension with a smaller height in the front suspension and the rear suspension.

[0089] After the two rear wheels of the electric vehicle leave the speed bump, for example Figure 4 As shown, when the electric vehicle travels to position 8, due to inertia, the front suspension and the rear suspension will be compressed and bounced multiple times under the action of inertia, and the height changes out of sync, which will also cause the electric vehicle to pitch, affecting the riding comfort.

[0090] Among them, the greater the height of the suspension, the lighter the unsprung mass of the suspension; the smaller the height of the suspension, the heavier the unsprung mass of the suspension.

[0091] By actively controlling the torque output by the drive motor corresponding to the suspension with a greater height in the front suspension and the rear suspension of the electric vehicle to be greater than the torque output by the drive motor corresponding to the suspension with a smaller height in the front suspension and the rear suspension, adjust the unsprung mass of the front suspension and the rear suspension, and quickly control the height of the front suspension and the rear suspension to change synchronously after the two rear wheels leave the speed bump. The front axle and the rear axle of the electric vehicle change synchronously, reducing the pitching of the electric vehicle and improving the riding comfort.

[0092] In one embodiment, the difference between the torque output by the drive motor corresponding to the suspension with a greater height in the front suspension and the rear suspension and the torque output by the drive motor corresponding to the suspension with a smaller height in the front suspension and the rear suspension increases as the height difference between the front suspension and the rear suspension increases.

[0093] In this embodiment, the greater the height difference between the front suspension and the rear suspension, the greater the difference in unsprung mass between the front suspension and the rear suspension, and the greater the pitching of the electric vehicle. By actively controlling the difference between the torque output by the drive motor corresponding to the suspension with a greater height in the front suspension and the rear suspension and the torque output by the drive motor corresponding to the suspension with a smaller height in the front suspension and the rear suspension to increase as the height difference between the front suspension and the rear suspension increases, it is possible to flexibly adjust the torque output by the front drive motor and the rear drive motor when the height difference between the front suspension and the rear suspension is different, so as to adjust the unsprung mass of the front suspension and the rear suspension, achieve quick control of the height of the front suspension and the rear suspension to change synchronously, reduce the pitching of the electric vehicle, and improve the riding comfort.

[0094] The following will be combined with Figure 4 and Figure 5 to detail the control method for reducing the pitching of the electric vehicle during the process of passing through the speed bump.

[0095] Among them, the control method for reducing the pitch of an electric vehicle during the acceleration through a speed bump by the two front wheels of the electric vehicle is described by the control steps from the first moment t1 to the fourth moment t4, and the control method for reducing the pitch of the electric vehicle during the acceleration through a speed bump by the two rear wheels of the electric vehicle is described by the control steps from the fifth moment t5 to the seventh moment t7.

[0096] After the first moment when the two front wheels contact the speed bump and before the second moment when the two front wheels reach the highest point of the speed bump, control both the front drive motor and the rear drive motor to output the torque indicated by the torque signal.

[0097] Among them, the torque indicated by the torque signal is the torque indicated by the opening of the accelerator pedal.

[0098] At the first moment t1, the two front wheels contact the speed bump and the front suspension compresses.

[0099] At the second moment t2, the two front wheels reach the highest point of the speed bump and the front suspension compresses to the maximum.

[0100] At any moment between the first moment t1 and the second moment t2, that is, at any moment between the two front wheels contacting the speed bump and driving to the highest point of the speed bump, control both the front drive motor and the rear drive motor to output the torque indicated by the torque signal. For example, when the electric vehicle drives to the moment at position 2 as shown in Figure 4 the figure.

[0101] As shown in Figure 5 the figure, after the first moment t1, the height of the front suspension decreases, the height of the rear suspension remains unchanged, and the torque output by the front drive motor to the two front wheels and the torque output by the rear drive motor of the electric vehicle to the two rear wheels remain unchanged.

[0102] At the second moment t2, the height of the front suspension decreases to a minimum value, the height of the rear suspension remains unchanged, and the torque output by the front drive motor to the two front wheels and the torque output by the rear drive motor to the two rear wheels remain unchanged.

[0103] After the second moment and before the third moment when the two front wheels leave the speed bump, actively control the torque output by the front drive motor to decrease and the torque output by the rear drive motor to increase.

[0104] After the second moment t2, the two front wheels leave the highest point of the speed bump and the front suspension rebounds.

[0105] At the third moment t3, the two front wheels leave the speed bump and contact the road surface, the front suspension compresses again, and the height of the front suspension begins to decrease.

[0106] At any time between the second moment t2 and the third moment t3, that is, at any time between when the two front wheels reach the highest point of the speed bump and leave the speed bump to contact the road surface, and at any time during the upward movement of the front suspension, actively control the torque output by the front drive motor to decrease and the torque output by the rear drive motor to increase. For example, when the electric vehicle travels to the position 3 as shown in Figure 4 shown.

[0107] Between the second moment t2 and the third moment t3, reduce the torque output by the front drive motor to the two front wheels and increase the torque output by the rear drive motor to the two rear wheels, so that the unsprung mass of the front suspension increases and the unsprung mass of the rear suspension decreases, the wheel-end natural frequency of the front suspension decreases, and the wheel-end natural frequency of the rear suspension increases, realizing rapid adjustment of the wheel-end natural frequency of the suspension.

[0108] The decrease in the wheel-end natural frequency of the front suspension makes the vibration response of the vehicle body slow under external excitation (such as when the front wheels pass over the speed bump), and the ride comfort is better.

[0109] During this process, the unsprung mass of the rear suspension decreases, the rear suspension rebounds, and the heights of both the front suspension and the rear suspension increase. The front axle and the rear axle of the electric vehicle change in the same frequency.

[0110] As Figure 5 shown, after the second moment t2, the height of the front suspension increases, the height of the rear suspension increases, the torque output by the front drive motor to the two front wheels decreases, and the torque output by the rear drive motor of the electric vehicle to the two rear wheels increases.

[0111] At the third moment t3, the height of the front suspension increases to a maximum value, the torque output by the front drive motor to the two front wheels decreases to a minimum value, and the torque output by the rear drive motor to the two rear wheels increases to a maximum value.

[0112] In this embodiment, during the process of the electric vehicle accelerating through the speed bump, after the second moment when the two front wheels reach the highest point of the speed bump and before the third moment when the two front wheels leave the speed bump, by actively controlling the torque output by the front drive motor to decrease and the torque output by the rear drive motor to increase, it is possible to adjust the increase in the unsprung mass of the front suspension and the decrease in the unsprung mass of the rear suspension, so that the heights of the front suspension and the rear suspension increase in the same frequency, and the front axle and the rear axle of the electric vehicle change in the same frequency, thereby reducing the pitch of the electric vehicle and improving the ride comfort. At the same time, the wheel-end natural frequency of the front suspension is reduced, so that the vibration response of the vehicle body is slow when the front wheels pass over the speed bump, further improving the ride comfort.

[0113] After the third moment t3 and before the fourth moment t4 when the front suspension rebounds, actively control the torque output by the front drive motor to increase and the torque output by the rear drive motor to decrease.

[0114] After the third moment \(t3\), the two front wheels contact the road surface, the front suspension compresses, and the height of the front suspension decreases.

[0115] At the fourth moment \(t4\), the front suspension rebounds again, and the height of the front suspension begins to increase after decreasing to a minimum value.

[0116] At any moment between the third moment \(t3\) and the fourth moment \(t4\), that is, at any moment when the two front wheels leave the speed bump until the front suspension rebounds due to inertia, and at any moment during the compression process of the front suspension, the torque output by the active control front drive motor increases and the torque output by the rear drive motor decreases. For example, when the electric vehicle travels to the position 4 as shown in Figure 4 the moment shown.

[0117] Between the third moment \(t3\) and the fourth moment \(t4\), increase the torque output by the front drive motor to the two front wheels and decrease the torque output by the rear drive motor to the two rear wheels, so that the unsprung mass of the front suspension decreases and the unsprung mass of the rear suspension increases, the wheel-end frequency of the front suspension increases, and the wheel-end frequency of the rear suspension decreases, realizing a rapid adjustment of the wheel-end frequency of the suspension.

[0118] The increase in the wheel-end frequency of the front suspension and the decrease in the wheel-end frequency of the rear suspension here actually make the wheel-end frequencies of the two front wheels and the rear suspension return to their natural frequencies when not affected by external excitation.

[0119] During this process, the unsprung mass of the rear suspension increases, the rear suspension compresses, and the heights of both the front suspension and the rear suspension decrease, and the changes in the front axle and rear axle of the electric vehicle achieve the same frequency.

[0120] As Figure 5 shown, after the third moment \(t3\), the height of the front suspension decreases, the height of the rear suspension decreases, the torque output by the front drive motor to the two front wheels increases, and the torque output by the rear drive motor of the electric vehicle to the two rear wheels decreases.

[0121] At the fourth moment \(t4\), the height of the front suspension decreases to a minimum value, the torque output by the front drive motor to the two front wheels increases to a maximum value, and the torque output by the rear drive motor to the two rear wheels decreases to a minimum value.

[0122] In this embodiment, during the process of the electric vehicle accelerating through the speed bump, after the third moment when the two front wheels leave the speed bump and before the fourth moment when the front suspension rebounds, by actively controlling the increase in the torque output by the front drive motor and the decrease in the torque output by the rear drive motor, it is possible to adjust the decrease in the unsprung mass of the front suspension and the increase in the unsprung mass of the rear suspension, so that the heights of the front suspension and the rear suspension decrease in the same frequency, and the front axle and rear axle of the electric vehicle change in the same frequency, thereby reducing the pitch of the electric vehicle and improving the riding comfort.

[0123] At this point, the two front wheels have passed over the speed bump. After the fourth moment t4, due to inertia, the front suspension will still be in a state of compression and bounce multiple times. Under the action of damping, the vibration amplitude of the suspension gradually decreases until the vibration stops. When the front suspension compresses and bounces due to inertia, the same as the above steps, the torque output by the drive motor corresponding to the suspension with a higher height in the front suspension and rear suspension of the electric vehicle is greater than the torque output by the drive motor corresponding to the suspension with a lower height in the front suspension and rear suspension, so that the changes in the front axle and rear axle of the electric vehicle are in the same frequency, reducing the pitch of the electric vehicle.

[0124] After the fifth moment t5 when the two rear wheels contact the speed bump and before the sixth moment t6 when the two rear wheels reach the highest point of the speed bump, control both the front drive motor and the rear drive motor to output the torque indicated by the torque signal.

[0125] At the fifth moment t5, the two rear wheels contact the speed bump and the rear suspension compresses.

[0126] At the sixth moment t6, the two rear wheels reach the highest point of the speed bump and the rear suspension is compressed to the maximum.

[0127] At any moment between the fifth moment t5 and the sixth moment t6, that is, at any moment between the two rear wheels contacting the speed bump and driving to the highest point of the speed bump, control both the front drive motor and the rear drive motor to output the torque indicated by the torque signal. For example, when the electric vehicle travels to the moment at position 5 as shown in Figure 4 shown.

[0128] As Figure 5 shown, after the fifth moment t5, the height of the rear suspension decreases, and the torque output by the front drive motor to the two front wheels and the torque output by the rear drive motor of the electric vehicle to the two rear wheels remain unchanged.

[0129] At the sixth moment t6, the height of the rear suspension decreases to a minimum value, and the torque output by the front drive motor to the two front wheels and the torque output by the rear drive motor to the two rear wheels remain unchanged.

[0130] By controlling both the front drive motor and the rear drive motor to output the torque indicated by the torque signal, the electric vehicle can accelerate at the acceleration desired by the user.

[0131] In one embodiment, the fifth moment and the sixth moment can be the moments when the body sensor detects that the height of the rear suspension decreases.

[0132] In another embodiment, the fifth moment and the sixth moment can be predicted and determined. The method for predicting the fifth moment includes: predicting the fifth moment t5 and the sixth moment t6 according to the first moment t1, the second moment t2, the vehicle speed of the electric vehicle, the acceleration of the electric vehicle, and the distance between the front wheels and the rear wheels of the electric vehicle.

[0133] Similarly, for subsequent seventh moment, it can be predicted and determined. Between the predicted and determined fifth moment t5 and sixth moment t6, and between the sixth moment t6 and seventh moment t7, according to the control methods of the front drive motor and rear drive motor during the process of the two front wheels passing over the speed bump (between the first moment t1 and second moment t2, and between the second moment t2 and third moment t3), control the torque output of the front drive motor and rear drive motor between the fifth moment t5 and sixth moment t6, and between the sixth moment t6 and seventh moment t7.

[0134] In this embodiment, by obtaining relevant information when the two front wheels pass over the speed bump, predicting the moments when the torque of the drive motors needs to be adjusted when the two rear wheels pass over the speed bump is beneficial for subsequent feedforward control of the torque output of the drive motors when the two rear wheels pass over the speed bump based on the torque output data of the drive motors when the two front wheels pass over the speed bump, and is beneficial for better controlling the overall vehicle attitude during the process of the electric vehicle passing over the speed bump and improving the ride experience.

[0135] Similarly, the prediction method for the sixth moment provided in this embodiment can also be used to predict the corresponding fifth moment, sixth moment, and seventh moment during the process of the electric vehicle braking and passing over the speed bump.

[0136] After the sixth moment t6 and before the seventh moment t7 when the two rear wheels leave the speed bump, actively control the torque output by the front drive motor to increase and the torque output by the rear drive motor to decrease.

[0137] After the sixth moment t6, the two rear wheels pass over the highest point of the speed bump, and the rear suspension rebounds.

[0138] At the seventh moment t7, the two rear wheels leave the speed bump and contact the road surface, the rear suspension is compressed again, and the height of the rear suspension begins to decrease.

[0139] At any moment between the sixth moment t6 and the seventh moment t7, that is, at any moment between the two rear wheels reaching the highest point of the speed bump and leaving the speed bump and contacting the road surface, and at any moment during the process of the rear suspension rebounding, actively control the torque output by the front drive motor to increase and the torque output by the rear drive motor to decrease. For example, when the electric vehicle travels to the moment at position 6 as shown in Figure 4 the figure.

[0140] Between the sixth moment t6 and the seventh moment t7, increase the torque output by the front drive motor to the two front wheels and decrease the torque output by the rear drive motor to the two rear wheels, so that the unsprung mass of the front suspension decreases and the unsprung mass of the rear suspension increases, the wheel end frequency of the front suspension increases, and the wheel end frequency of the rear suspension increases, realizing rapid adjustment of the wheel end frequency of the suspension.

[0141] The off-frequency of the rear suspension wheel end decreases, making the vibration response of the vehicle body relatively slow when the rear suspension is subjected to external excitation (such as when the rear wheels pass over a speed bump), and the ride comfort is better.

[0142] During this process, the unsprung mass of the front suspension decreases, the front suspension rebounds, the heights of both the front suspension and the rear suspension increase, and the front and rear axles of the electric vehicle change in the same frequency.

[0143] Such as Figure 5 As shown, after the sixth moment t6, the height of the front suspension increases, the height of the rear suspension increases, the torque output by the front drive motor to the two front wheels increases, and the torque output by the rear drive motor of the electric vehicle to the two rear wheels decreases.

[0144] At the seventh moment t7, the height of the rear suspension increases to a maximum value, the torque output by the front drive motor to the two front wheels increases to a maximum value, and the torque output by the rear drive motor to the two rear wheels decreases to a minimum value.

[0145] In this embodiment, during the process of the electric vehicle accelerating through a speed bump, after the sixth moment when the two rear wheels reach the highest point of the speed bump and before the seventh moment when the two rear wheels leave the speed bump, by actively controlling the increase in the torque output by the front drive motor and the decrease in the torque output by the rear drive motor, it is possible to adjust the decrease in the unsprung mass of the front suspension and the increase in the unsprung mass of the rear suspension, so that the heights of the front suspension and the rear suspension increase in the same frequency, and the front and rear axles of the electric vehicle change in the same frequency, thereby reducing the pitch of the electric vehicle and improving the ride experience. At the same time, the off-frequency of the rear suspension wheel end is reduced, making the vibration response of the vehicle body slow when the rear wheels pass over a speed bump, and improving the ride comfort.

[0146] After the seventh moment t7 and before the eighth moment t8 when the rear suspension rebounds, actively control the reduction of the torque output by the front drive motor and the increase of the torque output by the rear drive motor.

[0147] After the seventh moment t7, the two rear wheels contact the road surface, the rear suspension compresses, and the height of the rear suspension decreases.

[0148] At the eighth moment t8, the rear suspension rebounds again, and the height of the rear suspension begins to increase after decreasing to a minimum value.

[0149] At any moment between the seventh moment t7 and the eighth moment t8, that is, at any moment when the two rear wheels leave the speed bump until the rear suspension rebounds due to inertia, and at any moment during the compression process of the front suspension, actively control the reduction of the torque output by the front drive motor and the increase of the torque output by the rear drive motor. For example, when the electric vehicle travels to the moment at position 7 as Figure 4 shown.

[0150] Between the seventh moment t7 and the eighth moment t8, the torque output by the front drive motor to the two front wheels is decreased and the torque output by the rear drive motor to the two rear wheels is increased, so that the unsprung mass of the front suspension is increased and the unsprung mass of the rear suspension is decreased, the wheel-end natural frequency of the front suspension is decreased, and the wheel-end natural frequency of the rear suspension is increased, achieving a rapid adjustment of the wheel-end natural frequency of the suspension.

[0151] The decrease in the wheel-end natural frequency of the front suspension and the increase in the wheel-end natural frequency of the rear suspension here actually make the wheel-end natural frequencies of the two front wheels and the rear suspension return to their natural frequencies when not affected by external excitation.

[0152] During this process, the unsprung mass of the rear suspension is increased, the rear suspension is compressed, the heights of both the front suspension and the rear suspension are decreased, and the changes in the front axle and the rear axle of the electric vehicle are in the same frequency.

[0153] As Figure 5 shown, after the seventh moment t7, the height of the front suspension is decreased, the height of the rear suspension is decreased, the torque output by the front drive motor to the two front wheels is decreased, and the torque output by the rear drive motor of the electric vehicle to the two rear wheels is increased.

[0154] At the eighth moment t8, the height of the rear suspension is decreased to a minimum value, the torque output by the front drive motor to the two front wheels is decreased to a minimum value, and the torque output by the rear drive motor to the two rear wheels is increased to a maximum value.

[0155] At this point, the two rear wheels have passed over the speed bump. After the eighth moment t8, due to inertia, the rear suspension will still be in a state of being compressed and bouncing several times. Under the action of damping, the vibration amplitude of the suspension gradually decreases until the vibration stops. When the rear suspension is compressed and bounces due to inertia, the same as the above steps, actively control the torque output of the drive motor corresponding to the suspension with a higher height in the front suspension and the rear suspension of the electric vehicle to be greater than the torque output of the drive motor corresponding to the suspension with a lower height in the front suspension and the rear suspension, so that the changes in the front axle and the rear axle of the electric vehicle are in the same frequency and the pitching of the electric vehicle is reduced.

[0156] Some more details about controlling the drive system to adjust the torque output from the first moment t1 to the eighth moment t8 are introduced below.

[0157] In one embodiment, after the second moment t2 and before the third moment t3, actively control the torque output by the front drive motor to the two front wheels to be less than the torque indicated by the torque signal and the torque output by the rear drive motor to the two rear wheels to be greater than the torque indicated by the torque signal; after the sixth moment t6 and before the seventh moment t7, actively control the torque output by the front drive motor to the two front wheels to be greater than the torque indicated by the torque signal and the torque output by the rear drive motor to the two rear wheels to be less than the torque indicated by the torque signal.

[0158] In this embodiment, during the process of an electric vehicle accelerating over a speed bump, by actively controlling the torque output by the front drive motor to the two front wheels to be less than the torque indicated by the torque signal and the torque output by the rear drive motor to the two rear wheels to be greater than the torque indicated by the torque signal, and by actively controlling the torque output by the front drive motor to the two front wheels to be greater than the torque indicated by the torque signal and the torque output by the rear drive motor to the two rear wheels to be less than the torque indicated by the torque signal, rather than waiting for the suspension system to buffer the bumps without adjusting the torque output of the drive motor, the riding comfort is improved.

[0159] In one embodiment, the difference between the amount of decrease in the torque output by the front drive motor to the two front wheels and the amount of increase in the torque output by the rear drive motor to the two rear wheels is less than a preset difference; the difference between the amount of increase in the torque output by the front drive motor to the two front wheels and the amount of decrease in the torque output by the rear drive motor to the two rear wheels is less than a preset difference.

[0160] In the embodiments of the present application, the specific value of the preset difference is not limited. Among them, the preset difference is a relatively small value, such as 3, 5, 8, etc. If the difference between the amount of decrease in the torque output by the front drive motor to the two front wheels and the amount of increase in the torque output by the rear drive motor to the two rear wheels is less than the preset difference, it is considered that the amount of decrease in the torque output by the front drive motor to the two front wheels and the amount of increase in the torque output by the rear drive motor to the two rear wheels are almost the same.

[0161] In this case, it can be considered that the total torque output by the drive motor to the four wheels remains unchanged, and the overall acceleration of the electric vehicle remains unchanged.

[0162] In this embodiment, during the process of an electric vehicle accelerating over a speed bump, by actively controlling the difference between the amount of decrease in the torque output by the front drive motor to the two front wheels and the amount of increase in the torque output by the rear drive motor to the two rear wheels to be less than the preset difference; and actively controlling the difference between the amount of increase in the torque output by the front drive motor to the two front wheels and the amount of decrease in the torque output by the rear drive motor to the two rear wheels to be less than the preset difference, the total torque output by the drive motor to the electric vehicle remains unchanged, and the overall acceleration of the electric vehicle is stable, so that the change in the front and rear axles of the vehicle can be adjusted in the same frequency without the user's perception, improving the riding experience.

[0163] In one embodiment, the height of the suspension of the four wheels is determined according to the height signal of the suspension indicated by the height sensors of the four wheels and / or the acceleration signal of the acceleration sensor in the vertical direction indicating the acceleration.

[0164] Among them, the wheel height sensor can accurately measure the height change of the wheel relative to the vehicle body, that is, the suspension. The acceleration sensor in the vertical direction can accurately measure the acceleration change of the vehicle in the vertical direction, and the height change of the front suspension and the rear suspension can be reflected through the acceleration.

[0165] In the embodiment of the present application, the electric vehicle 100 is at least equipped with two wheel height sensors and / or two acceleration sensors in the vertical direction to monitor the height changes of the front suspension and the rear suspension.

[0166] In this embodiment, both the height signal of the wheel height sensor and the acceleration signal of the acceleration sensor in the vertical direction are signals that can be directly obtained. Based on the height signal and the acceleration signal, the height of the wheel suspension can be accurately determined, thereby improving the accuracy of subsequent control.

[0167] Next, a control method for reducing the pitch of an electric vehicle provided in the embodiment of the present application during the process of the electric vehicle braking and passing over a speed bump will be described.

[0168] The control method for reducing the pitch of an electric vehicle provided in the embodiment of the present application includes the following steps.

[0169] Before the two front wheels of the electric vehicle touch the speed bump, control the reverse torque output by the front drive motor of the electric vehicle to the two front wheels and the reverse torque output by the rear drive motor of the electric vehicle to the two rear wheels according to the opening of the brake pedal; the direction of the reverse torque is opposite to the direction of wheel rotation.

[0170] Before the two front wheels touch the speed bump, control the front drive motor to output the reverse torque indicated by the opening of the brake pedal to the two front wheels and the rear drive motor to output the reverse torque indicated by the opening of the brake pedal to the two rear wheels.

[0171] For ease of understanding, please refer to Figure 6 , Figure 6 which shows a schematic diagram of a control method for an electric vehicle 100, Figure 6 taking the case where the opening of the brake pedal remains unchanged as an example.

[0172] Before the first moment t1, the electric vehicle travels to the position 1 as shown in Figure 4 , and the four wheels do not touch the speed bump. As shown in Figure 6 , the heights of the front suspension and the rear suspension have not changed. In response to the opening of the acceleration pedal, control the front drive motor to output reverse torque to the two front wheels and the rear drive motor of the electric vehicle to output reverse torque to the two rear wheels.

[0173] During the process of the electric vehicle passing over the speed bump, actively control the front drive motor and the rear drive motor to adjust the output reverse torque.

[0174] Similarly, during the process of the electric vehicle passing over the speed bump, the positional relationship between the electric vehicle and the speed bump includes six positional relationships from position 2 to position 7 as shown in Figure 4 .

[0175] When an electric vehicle brakes, the center of gravity of the electric vehicle moves forward, the unsprung mass of the front suspension is large, and the unsprung mass of the rear suspension is small.

[0176] By actively controlling the reverse torque output by the front drive motor and the rear drive motor, the degree of forward movement of the center of gravity of the electric vehicle is adjusted, and the unsprung masses of the front suspension and the rear suspension are adjusted, so as to quickly adjust the cornering frequency at the wheel end of the suspension, enabling the heights of the front suspension and the rear suspension to change in the same frequency (for example, compressing and bouncing simultaneously), the front axle and the rear axle of the electric vehicle to change in the same frequency, reducing the pitch of the electric vehicle, and improving the riding comfort.

[0177] After the two rear wheels of the electric vehicle leave the speed bump, actively control the reverse torque output by the drive motor corresponding to the suspension with a higher height in the front suspension and the rear suspension of the electric vehicle to be greater than the reverse torque output by the drive motor corresponding to the suspension with a lower height in the front suspension and the rear suspension.

[0178] By actively controlling the reverse torque output by the drive motor corresponding to the suspension with a higher height in the front suspension and the rear suspension of the electric vehicle to be greater than the reverse torque output by the drive motor corresponding to the suspension with a lower height in the front suspension and the rear suspension, the unsprung masses of the front suspension and the rear suspension are adjusted, achieving rapid control of the heights of the front suspension and the rear suspension to change in the same frequency, the front axle and the rear axle of the electric vehicle to change in the same frequency, reducing the pitch of the electric vehicle, and improving the riding comfort.

[0179] Similarly, the control method provided in the embodiments of the present application is also applicable to the process of braking an electric vehicle through a braking system, and adjusts the braking force output by controlling the braking system to reduce the pitch of the electric vehicle and improve the riding comfort.

[0180] In one embodiment, the difference between the reverse torque output by the drive motor corresponding to the suspension with a higher height in the front suspension and the rear suspension and the reverse torque output by the drive motor corresponding to the suspension with a lower height in the front suspension and the rear suspension increases as the height difference between the front suspension and the rear suspension increases.

[0181] In this embodiment, the greater the height difference between the front suspension and the rear suspension, the greater the difference in the unsprung masses between the front suspension and the rear suspension, and the greater the pitch of the electric vehicle. By actively controlling the difference between the reverse torque output by the drive motor corresponding to the suspension with a higher height in the front suspension and the rear suspension and the reverse torque output by the drive motor corresponding to the suspension with a lower height in the front suspension and the rear suspension to increase as the height difference between the front suspension and the rear suspension increases, it is possible to flexibly adjust the reverse torque output by the front drive motor and the rear drive motor when the height difference between the front suspension and the rear suspension is different, so as to adjust the unsprung masses of the front suspension and the rear suspension, achieve rapid control of the heights of the front suspension and the rear suspension to change in the same frequency, reduce the pitch of the electric vehicle, and improve the riding comfort.

[0182] The following will be combined withFigure 4 and Figure 6 A control method for reducing the pitch of an electric vehicle during passing over a speed bump will be described in detail. Among them, the control steps from the first moment t1 to the fourth moment t4 describe the control method for reducing the pitch of the electric vehicle during the braking of the two front wheels of the electric vehicle when passing over the speed bump, and the control steps from the fifth moment t5 to the seventh moment t7 describe the control method for reducing the pitch of the electric vehicle during the braking of the two rear wheels of the electric vehicle when passing over the speed bump.

[0183] During the process of the electric vehicle braking and passing over the speed bump, the positional relationship between the electric vehicle and the speed bump at each moment is the same as that during the process of the electric vehicle accelerating and passing over the speed bump.

[0184] After the first moment t1 when the two front wheels contact the speed bump and before the second moment t2 when the two front wheels reach the highest point of the speed bump, control both the front drive motor and the rear drive motor to output the reverse torque indicated by the torque signal.

[0185] At any moment between the first moment t1 and the second moment t2, that is, at any moment between the two front wheels from contacting the speed bump to traveling to the highest point of the speed bump, control both the front drive motor and the rear drive motor to output the reverse torque indicated by the torque signal. For example, the moment when the electric vehicle travels to the position 2 as Figure 4 shown.

[0186] As Figure 6 shown, after the first moment t1, the height of the front suspension decreases, the height of the rear suspension remains unchanged, the reverse torque output by the front drive motor to the two front wheels and the reverse torque output by the rear drive motor of the electric vehicle to the two rear wheels remain unchanged.

[0187] At the second moment t2, the height of the front suspension decreases to a minimum value, the height of the rear suspension remains unchanged, the reverse torque output by the front drive motor to the two front wheels and the reverse torque output by the rear drive motor to the two rear wheels remain unchanged.

[0188] By controlling both the front drive motor and the rear drive motor to output the reverse torque indicated by the torque signal, the electric vehicle can decelerate at a deceleration desired by the user.

[0189] After the second moment t2 and before the third moment t3 when the two front wheels leave the speed bump, actively control the reverse torque output by the front drive motor to increase and the reverse torque output by the rear drive motor to decrease.

[0190] At any moment between the second moment t2 and the third moment t3, that is, at any moment between when the two front wheels reach the highest point of the speed bump and leave the speed bump and touch the road surface, and at any moment during the upward movement of the front suspension, actively control the increase of the reverse torque output by the front drive motor and the decrease of the reverse torque output by the rear drive motor. For example, when the electric vehicle travels to the position as shown in Figure 4 at moment 3.

[0191] Between the second moment t2 and the third moment t3, increase the reverse torque output by the drive motor to the two front wheels and decrease the reverse torque output by the drive motor to the two rear wheels, so that the unsprung mass of the front suspension increases and the unsprung mass of the rear suspension decreases, the wheel-end natural frequency of the front suspension decreases, and the wheel-end natural frequency of the rear suspension increases, realizing the rapid adjustment of the wheel-end natural frequency of the suspension.

[0192] The decrease in the wheel-end natural frequency of the front suspension makes the vibration response of the vehicle body slow when the front suspension is excited by the outside world (such as the front wheels passing over a speed bump), and the ride comfort is better.

[0193] During this process, the unsprung mass of the rear suspension decreases, the rear suspension bounces up, the heights of both the front suspension and the rear suspension increase, and the front and rear axles of the electric vehicle change in the same frequency.

[0194] As shown in Figure 6 after the second moment t2, the height of the front suspension increases, the height of the rear suspension increases, the reverse torque output by the front drive motor to the two front wheels increases, and the reverse torque output by the rear drive motor of the electric vehicle to the two rear wheels decreases.

[0195] At the third moment t3, the height of the front suspension increases to a maximum value, the reverse torque output by the front drive motor to the two front wheels increases to a maximum value, and the reverse torque output by the rear drive motor to the two rear wheels decreases to a minimum value.

[0196] In this embodiment, during the process of the electric vehicle braking and passing over a speed bump, after the second moment when the two front wheels reach the highest point of the speed bump and before the third moment when the two front wheels leave the speed bump, by actively controlling the increase of the reverse torque output by the front drive motor and the decrease of the reverse torque output by the rear drive motor, it is possible to adjust the increase of the unsprung mass of the front suspension and the decrease of the unsprung mass of the rear suspension, so that the heights of the front suspension and the rear suspension increase in the same frequency, and the front and rear axles of the electric vehicle change in the same frequency, thereby reducing the pitch of the electric vehicle and improving the ride comfort. At the same time, the wheel-end natural frequency of the front suspension is reduced, so that the vibration response of the vehicle body is slow when the front wheels pass over the speed bump, further improving the ride comfort.

[0197] After the third moment t3 and before the fourth moment t4 when the front suspension bounces up, actively control the decrease of the reverse torque output by the front drive motor and the increase of the reverse torque output by the rear drive motor.

[0198] At any moment between the third moment t3 and the fourth moment t4, that is, at any moment before the front suspension bounces due to inertia after the two front wheels leave the speed bump, and at any moment during the compression process of the front suspension, the reverse torque output by the active control front drive motor decreases and the reverse torque output by the rear drive motor increases. For example, when the electric vehicle travels to the moment at position 4 as shown in Figure 4 shown.

[0199] Between the third moment t3 and the fourth moment t4, the reverse torque output by the drive motor to the two front wheels is decreased and the reverse torque output by the drive motor to the two rear wheels is increased, so that the unsprung mass of the front suspension is decreased and the unsprung mass of the rear suspension is increased, the wheel-end natural frequency of the front suspension is increased, and the wheel-end natural frequency of the rear suspension is decreased, realizing rapid adjustment of the wheel-end natural frequency of the suspension.

[0200] The increase in the wheel-end natural frequency of the front suspension and the decrease in the wheel-end natural frequency of the rear suspension here actually make the wheel-end natural frequencies of the two front wheels and the rear suspension return to their natural frequencies when not excited by the outside world.

[0201] During this process, the unsprung mass of the rear suspension is increased, the rear suspension is compressed, the heights of both the front suspension and the rear suspension are decreased, and the front axle and the rear axle of the electric vehicle change in the same frequency.

[0202] As Figure 6 shown, after the third moment t3, the height of the front suspension is decreased, the height of the rear suspension is decreased, the reverse torque output by the front drive motor to the two front wheels is decreased, and the reverse torque output by the rear drive motor of the electric vehicle to the two rear wheels is increased.

[0203] At the fourth moment t4, the height of the front suspension is decreased to a minimum value, the reverse torque output by the front drive motor to the two front wheels is decreased to a minimum value, and the reverse torque output by the rear drive motor to the two rear wheels is increased to a maximum value.

[0204] In this embodiment, during the process of the electric vehicle braking through the speed bump, after the third moment when the two front wheels leave the speed bump and before the fourth moment when the front suspension bounces, by actively controlling the decrease of the reverse torque output by the front drive motor and the increase of the reverse torque output by the rear drive motor, it is possible to adjust the decrease of the unsprung mass of the front suspension and the increase of the unsprung mass of the rear suspension, so that the heights of the front suspension and the rear suspension decrease in the same frequency, and the front axle and the rear axle of the electric vehicle change in the same frequency, thereby reducing the pitching of the electric vehicle and improving the riding comfort.

[0205] At this point, the two front wheels have passed over the speed bump. After the fourth moment t4, due to inertia, the front suspension will continue to be in a state of compression and rebound multiple times. Under the action of damping, the vibration amplitude of the suspension gradually decreases until the vibration stops. When the front suspension compresses and rebounds due to inertia, the same as the above steps, actively control the reverse torque output by the drive motor corresponding to the suspension with a higher height in the front suspension and rear suspension of the electric vehicle to be greater than the reverse torque output by the drive motor corresponding to the suspension with a lower height in the front suspension and rear suspension, so that the changes in the front axle and rear axle of the electric vehicle are in the same frequency, reducing the pitching of the electric vehicle.

[0206] After the fifth moment t5 when the two rear wheels contact the speed bump and before the sixth moment t6 when the two rear wheels reach the highest point of the speed bump, control both the front drive motor and the rear drive motor to output the reverse torque indicated by the torque signal.

[0207] At any moment between the fifth moment t5 and the sixth moment t6, that is, at any moment between the two rear wheels from contacting the speed bump to driving to the highest point of the speed bump, control both the front drive motor and the rear drive motor to output the reverse torque indicated by the torque signal. For example, when the electric vehicle travels to the moment at position 5 as shown in Figure 4 shown.

[0208] As Figure 6 shown, after the fifth moment t5, the height of the rear suspension decreases, and the reverse torque output by the front drive motor to the two front wheels and the reverse torque output by the rear drive motor of the electric vehicle to the two rear wheels remain unchanged.

[0209] At the sixth moment t6, the height of the rear suspension decreases to a minimum value, and the reverse torque output by the front drive motor to the two front wheels and the reverse torque output by the rear drive motor to the two rear wheels remain unchanged.

[0210] By controlling both the front drive motor and the rear drive motor to output the reverse torque indicated by the torque signal, the electric vehicle can decelerate at a deceleration expected by the user.

[0211] After the sixth moment t6 and before the seventh moment t7 when the two rear wheels leave the speed bump, actively control the reverse torque output by the front drive motor to decrease and the reverse torque output by the rear drive motor to increase.

[0212] At any moment between the sixth moment t6 and the seventh moment t7, that is, at any moment between the two rear wheels from reaching the highest point of the speed bump to leaving the speed bump and contacting the road surface, at any moment during the rebound process of the rear suspension, actively control the reverse torque output by the front drive motor to decrease and the reverse torque output by the rear drive motor to increase. For example, when the electric vehicle travels to the moment at position 6 as shown in Figure 4 shown.

[0213] Between the sixth moment t6 and the seventh moment t7, the reverse torque output by the drive motor to the two front wheels is reduced and the reverse torque output by the drive motor to the two rear wheels is increased, so that the unsprung mass of the front suspension is reduced and the unsprung mass of the rear suspension is increased, the wheel-end natural frequency of the front suspension is increased, and the wheel-end natural frequency of the rear suspension is reduced, achieving a rapid adjustment of the wheel-end natural frequency of the suspension.

[0214] The reduction of the wheel-end natural frequency of the rear suspension makes the vibration response of the vehicle body relatively slow under external excitation (such as when the rear wheels pass over a speed bump), and the ride comfort is better.

[0215] During this process, the unsprung mass of the front suspension is reduced, the front suspension rebounds, and the heights of both the front suspension and the rear suspension increase. The changes in the front axle and the rear axle of the electric vehicle are in the same frequency.

[0216] As Figure 6 shown, after the sixth moment t6, the height of the front suspension increases, the height of the rear suspension increases, the reverse torque output by the front drive motor to the two front wheels is reduced, and the reverse torque output by the rear drive motor of the electric vehicle to the two rear wheels is increased.

[0217] At the seventh moment t7, the height of the rear suspension increases to a maximum value, the reverse torque output by the front drive motor to the two front wheels is reduced to a minimum value, and the reverse torque output by the rear drive motor to the two rear wheels is increased to a maximum value.

[0218] In this embodiment, during the process of the electric vehicle braking and passing over a speed bump, after the sixth moment when the two rear wheels reach the highest point of the speed bump and before the seventh moment when the two rear wheels leave the speed bump, by actively controlling the reduction of the reverse torque output by the front drive motor and the increase of the reverse torque output by the rear drive motor, it is possible to adjust the reduction of the unsprung mass of the front suspension and the increase of the unsprung mass of the rear suspension, so that the heights of the front suspension and the rear suspension increase in the same frequency, and the front axle and the rear axle of the electric vehicle change in the same frequency, thereby reducing the pitch of the electric vehicle and improving the ride experience. The ride comfort is improved. At the same time, the wheel-end natural frequency of the rear suspension is reduced, so that the vibration response of the vehicle body is slow when the rear wheels pass over the speed bump, further improving the ride comfort.

[0219] After the seventh moment t7 and before the eighth moment t8 when the rear suspension rebounds, actively control the increase of the reverse torque output by the front drive motor and the reduction of the reverse torque output by the rear drive motor.

[0220] At any moment between the seventh moment t7 and the eighth moment t8, that is, at any moment when the two rear wheels leave the speed bump until the rear suspension rebounds due to inertia, and at any moment during the compression process of the front suspension, actively control the increase of the reverse torque output by the front drive motor and the reduction of the reverse torque output by the rear drive motor. For example, the moment when the electric vehicle travels to the position 7 as Figure 4 shown.

[0221] Between the seventh moment t7 and the eighth moment t8, increase the reverse torque output by the drive motor to the two front wheels and decrease the reverse torque output by the drive motor to the two rear wheels, so that the unsprung mass of the front suspension increases and the unsprung mass of the rear suspension decreases, the wheel-end natural frequency of the front suspension decreases, and the wheel-end natural frequency of the rear suspension increases, achieving a rapid adjustment of the wheel-end natural frequency of the suspension.

[0222] The decrease in the wheel-end natural frequency of the front suspension and the increase in the wheel-end natural frequency of the rear suspension here actually make the wheel-end natural frequencies of the two front wheels and the rear suspension return to their natural frequencies when not subjected to external excitation.

[0223] During this process, the unsprung mass of the rear suspension increases, the rear suspension compresses, the heights of both the front suspension and the rear suspension decrease, and the changes in the front axle and the rear axle of the electric vehicle are in the same frequency.

[0224] As Figure 6 shown, after the seventh moment t7, the height of the front suspension decreases, the height of the rear suspension decreases, the reverse torque output by the front drive motor to the two front wheels increases, and the reverse torque output by the rear drive motor of the electric vehicle to the two rear wheels decreases.

[0225] At the eighth moment t8, the height of the rear suspension decreases to a minimum value, the reverse torque output by the front drive motor to the two front wheels increases to a maximum value, and the reverse torque output by the rear drive motor to the two rear wheels decreases to a minimum value.

[0226] At this point, the two rear wheels have passed over the speed bump. After the eighth moment t8, due to inertia, the rear suspension will still be in a state of compressing and bouncing multiple times. Under the action of damping, the vibration amplitude of the suspension gradually decreases until the vibration stops. When the rear suspension compresses and bounces due to inertia, in the same way as the above steps, actively control the reverse torque output by the drive motor corresponding to the suspension with a higher height in the front suspension and the rear suspension of the electric vehicle to be greater than the reverse torque output by the drive motor corresponding to the suspension with a lower height in the front suspension and the rear suspension, so that the changes in the front axle and the rear axle of the electric vehicle are in the same frequency and reduce the pitching of the electric vehicle.

[0227] Some more details about controlling the drive system to adjust the reverse torque output between the first moment t1 and the eighth moment t8 are introduced below.

[0228] In an embodiment, after the second moment t2 and before the third moment t3, actively control the reverse torque output by the front drive motor to the two front wheels to be less than the reverse torque indicated by the torque signal, and the reverse torque output by the rear drive motor to the two rear wheels to be less than the reverse torque indicated by the torque signal; after the sixth moment t6 and before the seventh moment t7, actively control the reverse torque output by the front drive motor to the two front wheels to be greater than the reverse torque indicated by the torque signal, and the reverse torque output by the rear drive motor to the two rear wheels to be greater than the reverse torque indicated by the torque signal.

[0229] In this embodiment, during the process of the electric vehicle braking over a speed bump, by actively controlling the reverse torque output by the front drive motor to the two front wheels to be less than the reverse torque indicated by the torque signal, the reverse torque output by the rear drive motor to the two rear wheels to be less than the reverse torque indicated by the torque signal, and actively controlling the reverse torque output by the front drive motor to the two front wheels to be greater than the reverse torque indicated by the torque signal, and the reverse torque output by the rear drive motor to the two rear wheels to be greater than the reverse torque indicated by the torque signal, rather than not adjusting the reverse torque output of the drive motor or the braking force output of the braking system and waiting for the suspension system to buffer the bumps, the ride comfort is improved.

[0230] In an embodiment, the difference between the decrease amount of the reverse torque output by the front drive motor to the two front wheels and the increase amount of the reverse torque output by the rear drive motor to the two rear wheels is less than a preset difference; the difference between the increase amount of the reverse torque output by the front drive motor to the two front wheels and the decrease amount of the reverse torque output by the rear drive motor to the two rear wheels is less than a preset difference.

[0231] If the difference between the increase amount of the reverse torque output by the front drive motor to the two front wheels and the decrease amount of the reverse torque output by the rear drive motor to the two rear wheels is less than a preset difference, it is considered that the increase amount of the reverse torque output by the front drive motor to the two front wheels and the decrease amount of the reverse torque output by the rear drive motor to the two rear wheels are almost the same.

[0232] In this case, it can be considered that the total reverse torque output by the drive motor to the four wheels remains unchanged, and the overall deceleration of the electric vehicle remains unchanged.

[0233] In this embodiment, during the process of the electric vehicle braking over a speed bump, by actively controlling the difference between the decrease amount of the reverse torque output by the front drive motor to the two front wheels and the increase amount of the reverse torque output by the rear drive motor to the two rear wheels to be less than a preset difference; the difference between the increase amount of the reverse torque output by the front drive motor to the two front wheels and the decrease amount of the reverse torque output by the rear drive motor to the two rear wheels to be less than a preset difference, the total reverse torque output by the drive motor to the electric vehicle remains unchanged, and the overall deceleration of the electric vehicle is stable, so that the front and rear axles of the vehicle are adjusted in the same frequency without the user's perception, improving the ride experience.

[0234] An embodiment of the present application provides a motor controller for an electric vehicle 100, and the motor controller is configured to execute the control method for reducing the pitch of the electric vehicle provided in the above embodiment.

[0235] Please refer to Figure 7 , Figure 7 which shows a schematic diagram of a motor controller.

[0236] As Figure 7 shown, the vehicle controller receives a pedal signal, generates a torque signal when the received pedal signal indicates the opening of the accelerator pedal, and sends the torque signal to the motor controller. Before the two front wheels of the electric vehicle contact a speed bump, after the first moment and before the second moment, after the fifth moment and before the sixth moment, the motor controller controls the torque output of the drive motor in response to the torque signal. After the second moment and before the third moment, after the third moment and before the fourth moment, after the sixth moment and before the seventh moment, the motor controller sends a suspension adaptation function activation signal to the vehicle controller, and at the same time actively controls the drive motor to adjust the torque output. Wherein, the suspension adaptation function activation signal is used to indicate that the torque for actively controlling the drive motor to adjust the torque output is not equal to the torque indicated by the torque signal.

[0237] When the received pedal signal indicates the opening of the brake pedal, a torque signal is generated, and the torque signal is sent to the motor controller or a brake signal is sent to the brake controller. Before the two front wheels of the electric vehicle contact a speed bump, after the first moment and before the second moment, after the fifth moment and before the sixth moment, the motor controller controls the torque output of the drive motor in response to the torque signal or controls the braking force output of the braking system in response to the brake signal. After the second moment and before the third moment, after the third moment and before the fourth moment, after the sixth moment and before the seventh moment, the motor controller or the brake controller sends a suspension adaptation function activation signal to the vehicle controller, and at the same time the motor controller actively controls the drive motor to adjust the torque output or the braking system to adjust the braking force output.

[0238] Wherein, the motor controller also receives a height signal from a wheel height sensor and an acceleration signal from an acceleration sensor in the vertical direction sent by the CDC, and determines the height change of the suspension according to the height signal and / or the acceleration signal.

[0239] Wherein, the communication between the CDC, the motor controller and the vehicle controller is realized through a central gateway.

[0240] In another embodiment of the embodiments of the present application, an electric vehicle is further provided. The electric vehicle includes a drive system, a braking system, and the motor controller provided in the above embodiments. The motor controller is used to control the drive system and / or the braking system to implement the control method for reducing the pitch of the electric vehicle proposed in the embodiments of the present application.

[0241] It can be understood that all relevant contents of each step involved in the above method embodiments can be cited in the embodiments of the controller and the embodiments of the electric vehicle. The embodiments of the present application will not be repeated here.

[0242] Finally, it should be noted that the above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A control method for reducing the pitch of an electric vehicle, characterized in that, The control method is used to adjust the torque output by the drive system during the process of the electric vehicle accelerating through a speed bump to improve the riding comfort. The control method includes: Before the two front wheels of the electric vehicle contact the speed bump, control the torque output by the front drive motor of the electric vehicle to the two front wheels and the torque output by the rear drive motor of the electric vehicle to the two rear wheels according to the opening of the accelerator pedal; During the process of the electric vehicle passing through the speed bump, actively control the front drive motor and the rear drive motor to adjust the output torque; After the two rear wheels of the electric vehicle leave the speed bump, actively control the torque output by the drive motor corresponding to the suspension with a greater height in the front suspension and the rear suspension of the electric vehicle to be greater than the torque output by the drive motor corresponding to the suspension with a smaller height in the front suspension and the rear suspension.

2. The control method according to claim 1, characterized in that For the active control of the front drive motor and the rear drive motor to adjust the output torque, the control method specifically includes: After the first moment when the two front wheels contact the speed bump and before the second moment when the two front wheels reach the highest point of the speed bump, control both the front drive motor and the rear drive motor to output the torque indicated by the torque signal; After the second moment and before the third moment when the two front wheels leave the speed bump, actively control the torque output by the front drive motor to decrease and the torque output by the rear drive motor to increase.

3. The control method according to claim 2, wherein For the active control of the front drive motor and the rear drive motor to adjust the output drive torque, the control method further includes: After the third moment and before the fourth moment when the front suspension rebounds, actively control the torque output by the front drive motor to increase and the torque output by the rear drive motor to decrease.

4. The control method according to claim 3, wherein For the active control of the front drive motor and the rear drive motor to adjust the output drive torque, the control method further includes: After the fifth moment when the two rear wheels contact the speed bump and before the sixth moment when the two rear wheels reach the highest point of the speed bump, control both the front drive motor and the rear drive motor to output the torque indicated by the torque signal; After the sixth moment and before the seventh moment when the two rear wheels leave the speed bump, actively control the torque output by the front drive motor to increase and the torque output by the rear drive motor to decrease.

5. The control method according to claim 2 or 4, characterized in that The control method specifically includes: After the second moment and before the third moment, actively control the torque output by the front drive motor to the two front wheels to be less than the torque indicated by the torque signal and the torque output by the rear drive motor to the two rear wheels to be greater than the torque indicated by the torque signal; After the sixth moment and before the seventh moment, actively control the torque output by the front drive motor to the two front wheels to be greater than the torque indicated by the torque signal and the torque output by the rear drive motor to the two rear wheels to be less than the torque indicated by the torque signal.

6. The control method according to any one of claims 2-4, characterized in that, The control method specifically includes: Actively control the difference between the decrease amount of the torque output by the front drive motor to the two front wheels and the increase amount of the torque output by the rear drive motor to the two rear wheels to be less than a preset difference; The difference between the increased amount of the torque output by the front drive motor to the two front wheels and the decreased amount of the torque output by the rear drive motor to the two rear wheels actively controlled is less than a preset difference.

7. A control method for reducing the pitch of an electric vehicle, characterized in that, The control method is used to adjust the torque output by the drive system during the process of the electric vehicle braking through a speed bump to improve the riding comfort. The control method includes: Before the two front wheels of the electric vehicle contact the speed bump, control the reverse torque output by the front drive motor of the electric vehicle to the two front wheels and the reverse torque output by the rear drive motor of the electric vehicle to the two rear wheels according to the opening degree of the brake pedal; the direction of the reverse torque is opposite to the direction of the wheel rotation; During the process of the electric vehicle passing through the speed bump, actively control the front drive motor and the rear drive motor to adjust the output reverse torque; After the two rear wheels of the electric vehicle leave the speed bump, actively control the reverse torque output by the drive motor corresponding to the suspension with a greater height in the front suspension and the rear suspension of the electric vehicle to be greater than the reverse torque output by the drive motor corresponding to the suspension with a smaller height in the front suspension and the rear suspension.

8. The control method according to claim 7, wherein For the active control of the front drive motor and the rear drive motor to adjust the output reverse torque, the control method specifically includes: After the first moment when the two front wheels contact the speed bump and before the second moment when the two front wheels reach the highest point of the speed bump, control both the front drive motor and the rear drive motor to output the reverse torque indicated by the torque signal; After the second moment and before the third moment when the two front wheels leave the speed bump, actively control the reverse torque output by the front drive motor to increase and the reverse torque output by the rear drive motor to decrease.

9. The control method according to claim 8, wherein For the active control of the front drive motor and the rear drive motor to adjust the output driving reverse torque, the control method further includes: After the third moment and before the fourth moment when the front suspension rebounds, actively control the reverse torque output by the front drive motor to decrease and the reverse torque output by the rear drive motor to increase.

10. The control method according to claim 9, characterized in that For the active control of the front drive motor and the rear drive motor to adjust the output driving reverse torque, the control method further includes: After the fifth moment when the two rear wheels contact the speed bump and before the sixth moment when the two rear wheels reach the highest point of the speed bump, control both the front drive motor and the rear drive motor to output the reverse torque indicated by the torque signal; After the sixth moment and before the seventh moment when the two rear wheels leave the speed bump, actively control the reverse torque output by the front drive motor to decrease and the reverse torque output by the rear drive motor to increase.

11. The control method according to claim 8 or 10, characterized in that The control method specifically includes: After the second moment and before the third moment, actively control the reverse torque output by the front drive motor to the two front wheels to be less than the reverse torque indicated by the torque signal and the reverse torque output by the rear drive motor to the two rear wheels to be less than the reverse torque indicated by the torque signal; After the sixth moment and before the seventh moment, actively control the reverse torque output by the front drive motor to the two front wheels to be greater than the reverse torque indicated by the torque signal, and the reverse torque output by the rear drive motor to the two rear wheels to be greater than the reverse torque indicated by the torque signal.

12. The control method according to any one of claims 8-10, characterized in that, The control method specifically includes: Actively control the difference between the decrease in the reverse torque output by the front drive motor to the two front wheels and the increase in the reverse torque output by the rear drive motor to the two rear wheels to be less than a preset difference; Actively control the difference between the increase in the reverse torque output by the front drive motor to the two front wheels and the decrease in the reverse torque output by the rear drive motor to the two rear wheels to be less than a preset difference.

13. A motor controller, characterized in that, The motor controller is used to execute the control method according to any one of claims 1 to 6 and / or claims 7 to 12.

14. An electric vehicle, characterized in that, The electric vehicle includes the motor controller according to claim 13.

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