Control method for electric vehicle, motor controller and electric vehicle

Abstract

The invention discloses a control method for an electric vehicle, a motor controller and the electric vehicle, and relates to the technical field of new energy automobiles. The control method is used for controlling a driving system to output forward torque which is the same as the wheel speed direction or reverse torque which is opposite to the wheel speed direction to two rear wheels so as to improve the stability of the electric vehicle in the lane changing process. The control method comprises the step of controlling the driving system to output forward torque to the left rear wheel and output reverse torque to the right rear wheel after a first moment when the steering wheel begins to rotate leftwards and before a second moment when the steering wheel begins to rotate rightwards. And after the second moment and before a third moment when the steering wheel starts to return to the left, the driving system is controlled to output reverse torque to the left rear wheel and output forward torque to the right rear wheel. And after the third moment and before a fourth moment when the steering wheel returns to the right, the driving system is controlled to output forward torque to the left rear wheel and output reverse torque to the right rear wheel. According to the scheme, the safety and stability of the electric vehicle are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electric vehicles, and more particularly, to a control method for an electric vehicle, a motor controller and an electric vehicle. BACKGROUND

[0002] When an electric vehicle encounters an emergency situation such as an obstacle in front or a vehicle component failure out of control at high speed, it is one of the most extreme tests of the stability of the electric vehicle. When an emergency lane change is needed, the driver usually quickly and greatly turns the steering wheel, which is extremely easy to cause the vehicle's center of gravity to shift sharply and break the tire grip limit, so that understeering or more dangerous oversteering may occur, and the vehicle body may completely deviate from the intended route. Under the working condition of vehicle emergency lane change, the electronic stability control system (ESC) is a key safety technology for maintaining dynamic stability. The electronic stability control system accurately identifies the instability trend by monitoring the vehicle state parameters in real time, and generates a compensatory return torque by applying a braking force to a single wheel based on a control algorithm, thereby effectively inhibiting the vehicle body roll and making the actual driving route track the driver's intended path to the maximum extent. However, the electronic stability system only relies on the braking system to control the electric vehicle during the emergency lane change process, lacks control coordination, and is prone to loss of control of the electric vehicle once the braking system fails.

[0003] Therefore, how to utilize the driving system to perform stable control during the emergency lane change process of the electric vehicle is a problem to be solved. SUMMARY

[0004] The present application provides a control method for an electric vehicle, a motor controller and an electric vehicle, which utilizes the driving system to output a reverse torque to one side of the wheels, so that differential torque is generated on both sides of the vehicle body, a compensatory return torque is generated, and the vehicle roll is corrected, thereby ensuring the safety of the electric vehicle during lane change and improving the safety and stability of the electric vehicle.

[0005] In a first aspect, the present application provides a control method for an electric vehicle, which is used to improve the stability of the electric vehicle during lane change by controlling the driving system to output forward torque or reverse torque in the same direction as the wheel speed to two rear wheels, the control method comprising: after a first time when the steering wheel starts to turn left, and before a second time when the steering wheel starts to turn right, controlling the driving system to output forward torque to the left rear wheel and reverse torque to the right rear wheel. After the second time, and before a third time when the steering wheel starts to return to the left, controlling the driving system to output reverse torque to the left rear wheel and forward torque to the right rear wheel. After the third time, and before a fourth time when the steering wheel returns to the center, controlling the driving system to output forward torque to the left rear wheel and reverse torque to the right rear wheel.

[0006] The size of the reverse torque in this application is the absolute value of the output torque of the drive system, and increasing the output of the reverse torque is equal to increasing the absolute value of the output torque. During the forward driving of the electric vehicle, the positive torque is used to drive the vehicle, and the negative torque is used to brake the vehicle, at this time the forward torque is positive torque, and the reverse torque is negative torque. The drive system changes the phase of the three-phase current output by the motor controller to the drive motor, so that the rotor cuts the magnetic field generated by the stator winding, and the kinetic energy of the rotor becomes electric energy input into the power battery, at this time the drive motor outputs negative torque. The motor controller changes the size of the three-phase current output to the motor, which can increase or decrease the positive torque or negative torque output by the drive. It should be understood that during the reverse driving of the electric vehicle, the positive torque is used to brake the vehicle, and the negative torque is used to drive the vehicle. In this application, the forward driving of the electric vehicle is taken as an example for description, and the similar description can be referred to in the reverse driving of the electric vehicle, the direction of the torque output by the drive motor can be modified accordingly, and the function of the torque should be kept consistent.

[0007] When the electric vehicle needs to change lanes in an emergency, for example, an obstacle appears on the driving route of the electric vehicle and needs to be avoided, the driver will quickly turn the steering wheel to one side to make the electric vehicle quickly change the driving route to change lanes and avoid obstacles. After entering the new road, the driver immediately reverses the steering wheel to make the vehicle head of the electric vehicle change to guide the driving route to the correct route. After the electric vehicle passes the obstacle, the driver will turn the steering wheel to the other side, and the electric vehicle will change lanes again. During the emergency lane change, the path change of the vehicle completely depends on the friction between the tire and the ground, and the tire is easy to reach the limit of the grip during the emergency lane change, which may cause the electric vehicle to lose control. Therefore, the yaw of the electric vehicle needs to be controlled to improve the stability of driving, so that the electric vehicle can change lanes as expected by the driver.

[0008] At the first moment, the steering wheel starts to turn to the left, and the electric vehicle changes lanes to the left. Since it is an emergency lane change, the electric vehicle may turn too much. In order to ensure stability, the electric vehicle needs to generate a right correction moment. At this time, the control drive system outputs positive torque to the left rear wheel and outputs reverse torque to the right rear wheel, so that for the two wheels of the rear axle, the left wheel receives positive torque and the right wheel receives reverse torque, so that the torque received by the left and right sides is different, which will make the vehicle generate a right correction moment to improve the stability of the electric vehicle.

[0009] At the second moment, the steering wheel starts to turn right, the driver countersteers the steering wheel to correct the yaw of the electric vehicle, and a leftward return torque needs to be generated for the electric vehicle. At this moment, the control system outputs a reverse torque to the left rear wheel and a forward torque to the right rear wheel, so that the left wheel of the two wheels of the rear axle receives a reverse torque and the right wheel receives a forward torque, and the magnitudes of the torques received by the left and right sides are different, so that the electric vehicle generates a leftward return torque to correct the yaw of the electric vehicle.

[0010] At the third moment, the steering wheel starts to turn left to correct the yaw of the electric vehicle, and a rightward return torque needs to be generated for the electric vehicle. At this moment, the control system outputs a reverse torque to the left rear wheel and a forward torque to the right rear wheel, so that the left wheel of the two wheels of the rear axle receives a forward torque and the right wheel receives a reverse torque, and the magnitudes of the torques received by the left and right sides are different, so that the electric vehicle generates a rightward return torque to improve the stability of the electric vehicle.

[0011] In another embodiment, before the sixth moment when the steering wheel starts to turn left after the fifth moment when the steering wheel starts to turn right, the control system outputs a forward torque to the right rear wheel and a reverse torque to the left rear wheel. After the sixth moment, before the seventh moment when the steering wheel starts to turn right to correct the yaw of the electric vehicle, the control system outputs a reverse torque to the right rear wheel and a forward torque to the left rear wheel. After the seventh moment, before the eighth moment when the steering wheel starts to turn right to correct the yaw of the electric vehicle, the control system outputs a forward torque to the right rear wheel and a reverse torque to the left rear wheel.

[0012] According to the scheme of the present application, during the emergency lane change of the electric vehicle, the control system outputs a forward torque and a reverse torque to the two rear wheels respectively, so that the electric vehicle generates a return torque for yaw stability control, thereby correcting the yaw of the electric vehicle and ensuring the safety of the electric vehicle during the emergency lane change.

[0013] In combination with the first aspect, in some implementations of the first aspect, the control method further includes, before the first moment, during straight driving when the steering wheel is not turned, controlling the drive system to output a forward torque to the two rear wheels. After the fourth moment, during straight driving when the steering wheel is not turned, controlling the drive system to output a forward torque to the two rear wheels.

[0014] Before the first moment, the electric vehicle drives straight, and the steering wheel is not turned. At this moment, the drive system outputs a forward torque to the two rear wheels to drive the electric vehicle.

[0015] After the fourth moment, the electric vehicle completes the emergency obstacle avoidance lane change process and returns to the straight driving state, and the steering wheel is not turned. At this moment, the drive system outputs a forward torque to the two rear wheels to drive the electric vehicle.

[0016] It should be understood that after the fourth moment, the electric vehicle can still not be completely stabilized due to inertia, and at this time the driver can fine-tune the steering wheel to stabilize the electric vehicle, and the driving system still outputs positive torque to the two rear wheels to drive the electric vehicle.

[0017] In combination with the first aspect, in some implementations of the first aspect, the control method further comprises controlling the driving system to output positive torque to the left rear wheel that varies with the opening degree of the accelerator pedal between the first moment and the second moment, between the third moment and the fourth moment. Controlling the driving system to output positive torque to the right rear wheel that varies with the opening degree of the accelerator pedal between the second moment and the third moment.

[0018] The accelerator pedal in the present application is also called a throttle pedal or an accelerator pedal. The opening degree of the accelerator pedal indicates the size of the driving force required by the driver, and the greater the opening degree of the accelerator pedal, the greater the demand of the driver for driving, and the greater the torque required to be output by the driving motor. The driving system controls the current output to the driving motor according to the opening degree of the accelerator pedal to make the driving motor output the torque indicated by the opening degree of the accelerator pedal, and the greater the opening degree of the accelerator pedal, the greater the current and the greater the torque output by the driving motor, and the smaller the opening degree of the accelerator pedal, the smaller the current and the smaller the torque output by the driving motor.

[0019] In the process of emergency lane changing, the driving system outputs positive torque to the steering side wheel, and the size of the positive torque varies with the opening degree of the accelerator pedal.

[0020] In another embodiment, after the fifth moment when the steering wheel starts to turn to the right, before the sixth moment when the steering wheel starts to turn to the left, the driving system is controlled to output positive torque to the right rear wheel that varies with the opening degree of the accelerator pedal. After the sixth moment, before the seventh moment when the steering wheel starts to turn to the right, the driving system is controlled to output positive torque to the left rear wheel that varies with the opening degree of the accelerator pedal. After the seventh moment, before the eighth moment when the steering wheel turns to the right, the driving system is controlled to output positive torque to the right rear wheel that varies with the opening degree of the accelerator pedal.

[0021] According to the scheme of the present application, in the process of emergency lane changing of the electric vehicle, the driving system outputs positive torque to the steering side rear wheel and is determined by the opening degree of the accelerator pedal, so that the electric vehicle adjusts the braking force according to the indication of the driver while performing yaw stability control, improves the operability of the electric vehicle, and ensures the safety of the electric vehicle during emergency lane changing.

[0022] With reference to the first aspect, in some implementations of the first aspect, the control method further includes, between the first time and the second time, when it is detected that the turning angle of the steering wheel is greater than a preset angle, or the turning speed of the steering wheel is greater than a preset speed, or the yaw angular velocity of the electric vehicle is greater than a preset yaw angular velocity, controlling the drive system to output a reverse torque to the right rear wheel.

[0023] At the first time, the steering wheel starts to turn to the left, and the electric vehicle determines whether to perform the emergency lane change according to the turning angle of the steering wheel. When the driver needs to perform the emergency lane change, the driver usually turns the steering wheel to one side by a large angle, and therefore the stable control is performed when the turning angle of the steering wheel is greater than the preset angle.

[0024] The preset angle is preset according to real vehicle experiments and / or model calculations, or is preset by comprehensively considering the overall vehicle demand and the vehicle performance.

[0025] At the first time, the steering wheel starts to turn to the left, and the electric vehicle determines whether to perform the emergency lane change according to the turning speed of the steering wheel. When the driver needs to perform the emergency lane change, the driver usually quickly turns the steering wheel to one side, and therefore the stable control is performed when the turning speed of the steering wheel is greater than the preset speed.

[0026] The preset speed is preset according to real vehicle experiments and / or model calculations, or is preset by comprehensively considering the overall vehicle demand and the vehicle performance.

[0027] At the first time, the steering wheel starts to turn to the left, and the electric vehicle determines whether to perform the emergency lane change according to the yaw angular velocity. When the electric vehicle performs the emergency lane change, the direction changes rapidly, and the yaw angular velocity rises rapidly, and therefore the stable control is performed when the yaw angular velocity is greater than the preset yaw angular velocity.

[0028] The preset yaw angular velocity is preset according to real vehicle experiments and / or model calculations, or is preset by comprehensively considering the overall vehicle demand and the vehicle performance.

[0029] In another embodiment, after a fifth time when the steering wheel starts to turn to the right, and before a sixth time when the steering wheel starts to turn to the left, when it is detected that the turning angle of the steering wheel is greater than a preset angle, or the turning speed of the steering wheel is greater than a preset speed, or the yaw angular velocity of the electric vehicle is greater than a preset yaw angular velocity, the drive system is controlled to output a reverse torque to the left rear wheel.

[0030] According to the scheme of the application, whether the electric vehicle is in an emergency lane change is determined according to the steering wheel rotation angle or rotation speed or yaw rate, so as to control whether the driving system adjusts the torque output to the two rear wheels. In a non-emergency lane change scenario, the driving system is controlled to output a positive torque indicated by the accelerator pedal to the two rear wheels, so that the driving capability of the electric vehicle is not affected. In an emergency lane change scenario, the driving system is controlled to output a reverse torque to one rear wheel, so as to correct the yaw of the electric vehicle, thereby ensuring the safety of the electric vehicle in the emergency lane change.

[0031] In combination with the first aspect, in some implementations of the first aspect, the control method specifically includes increasing the reverse torque output by the driving system to the right rear wheel with the increase of the accelerator pedal opening degree between the first time and the second time, and between the third time and the fourth time. The reverse torque output by the driving system to the left rear wheel is increased with the increase of the accelerator pedal opening degree between the second time and the third time.

[0032] The yaw rate of the electric vehicle during the emergency lane change is affected by the vehicle speed of the electric vehicle. The faster the vehicle speed, the greater the change of the yaw rate, and therefore the electric vehicle needs a greater righting torque to stabilize the electric vehicle. If the driver steps on the accelerator pedal, the vehicle speed of the electric vehicle will change. At this time, the size of the reverse torque output to the rear wheel is determined according to the size of the accelerator pedal opening degree.

[0033] In one implementation, the greater the vehicle speed of the electric vehicle, the greater the reverse torque output by the driving system to the right rear wheel between the first time and the second time, and between the third time and the fourth time. The greater the vehicle speed of the electric vehicle, the greater the reverse torque output by the driving system to the left rear wheel between the second time and the third time.

[0034] In another embodiment, the reverse torque output by the driving system to the left rear wheel is increased with the increase of the accelerator pedal opening degree after the fifth time when the steering wheel starts to turn right and before the sixth time when the steering wheel starts to turn left. The reverse torque output by the driving system to the right rear wheel is increased with the increase of the accelerator pedal opening degree after the sixth time and before the seventh time when the steering wheel starts to right. The reverse torque output by the driving system to the left rear wheel is increased with the increase of the accelerator pedal opening degree after the seventh time and before the eighth time when the steering wheel right.

[0035] According to the scheme of the application, during the emergency lane change of the electric vehicle, the size of the reverse torque output by the driving system to the rear wheel is determined according to the vehicle speed of the electric vehicle, so that the torque difference between the two rear wheels is within a suitable range, which can enable the electric vehicle to generate sufficient righting moment, more effectively correct the yaw of the electric vehicle, and improve the safety and stability of the electric vehicle in the emergency lane change.

[0036] In some implementations of the first aspect, the control method further includes, between the first time and the second time, and between the third time and the fourth time, controlling the drive system to increase the reverse torque output to the right rear wheel as the steering wheel rotation angle or the steering wheel rotation speed increases. Between the second time and the third time, controlling the drive system to increase the reverse torque output to the left rear wheel as the steering wheel rotation angle or the steering wheel rotation speed increases.

[0037] The yaw angular velocity of the electric vehicle during the emergency lane changing process is also affected by the steering wheel rotation angle and the steering wheel rotation speed. The greater the steering wheel rotation angle or the faster the steering wheel rotation speed, the greater the change in the yaw angular velocity of the electric vehicle, and thus the greater the return torque required by the electric vehicle to stabilize the electric vehicle. The greater the steering wheel rotation angle or the faster the steering wheel rotation speed, the greater the reverse torque output by the drive system to the rear wheels, and thus the greater the torque difference between the two rear wheels, which can generate a greater return moment for the electric vehicle.

[0038] According to the scheme of the present application, during the emergency lane changing process of the electric vehicle, the size of the reverse torque output by the drive system to the rear wheels is determined according to the steering wheel rotation angle or the steering wheel rotation speed of the electric vehicle, so that the torque difference between the two rear wheels is within a suitable range, which can generate sufficient return moment for the electric vehicle to more effectively correct the yaw of the electric vehicle and improve the safety and stability of the emergency lane changing of the electric vehicle.

[0039] In some implementations of the first aspect, the control method further includes, between the first time and the second time, and between the third time and the fourth time, controlling the drive system to increase the reverse torque output to the right rear wheel as the steering wheel rotation angle or the steering wheel rotation speed increases. Between the second time and the third time, controlling the drive system to increase the reverse torque output to the left rear wheel as the steering wheel rotation angle or the steering wheel rotation speed increases.

[0040] The control method is also used to improve the stability of the electric vehicle during the lane changing process by controlling the drive system to adjust the torque output to the two rear wheels and controlling the brake system to adjust the brake force output to the four wheels.

[0041] The brake system includes four wheel-end brake devices, each of which is used to output a brake force to a wheel of the electric vehicle. The four wheel-end brake devices correspond one-to-one to the four wheels, and the four wheel-end brake devices are used to output brake forces respectively. In a normal state, the four wheel-end brake devices are used to output brake forces indicated by the opening degree of the brake pedal.

[0042] The right turning demand of the electric vehicle between the first time and the second time and between the third time and the fourth time, the control brake system outputs the brake force to the two right wheels greater than the brake force to the two left wheels, so that the brake force to the two sides of the electric vehicle is not equal, and a right turning moment is generated to correct the yaw of the electric vehicle. Between the second time and the third time, the left turning demand of the electric vehicle, the control brake system outputs the brake force to the two right wheels less than the brake force to the two left wheels, so that the brake force to the two sides of the electric vehicle is not equal, and a right turning moment is generated to correct the yaw of the electric vehicle.

[0043] In another embodiment, after the fifth time when the steering wheel starts to turn right, before the sixth time when the steering wheel starts to turn left, the control brake system outputs the brake force to the two left wheels greater than the brake force to the two right wheels. After the sixth time, before the seventh time when the steering wheel starts to turn right, the control brake system outputs the brake force to the two right wheels greater than the brake force to the two left wheels. After the seventh time, before the eighth time when the steering wheel turns right, the control brake system outputs the brake force to the two left wheels greater than the brake force to the two right wheels.

[0044] According to the scheme of the present application, during the emergency lane change of the electric vehicle, even if the opening degree of the brake pedal does not change, by controlling the brake system to output unequal brake force to the left and right wheels of the electric vehicle, and adjusting the torque output to the two rear wheels by the drive system, the electric vehicle generates sufficient right turning moment to correct the yaw of the electric vehicle more effectively, and the safety and stability of the emergency lane change of the electric vehicle are improved.

[0045] In combination with the first aspect, in some implementations of the first aspect, the control method specifically includes between the first time and the second time and between the third time and the fourth time, increasing the brake force to the two right wheels of the electric vehicle with the increase of the accelerator pedal opening degree. Between the second time and the third time, increasing the brake force to the two left wheels of the electric vehicle with the increase of the accelerator pedal opening degree.

[0046] The yaw angular velocity of the electric vehicle during the emergency lane change is affected by the speed of the electric vehicle, the faster the speed, the greater the change of the yaw angular velocity, so the electric vehicle needs a larger right turning torque to stabilize the electric vehicle, and if the driver steps on the accelerator pedal, the speed of the electric vehicle will change, at this time, the size of the brake force output to the wheels on one side by the brake system is determined according to the opening degree of the accelerator pedal.

[0047] In one implementation, the greater the vehicle speed of the electric vehicle between the first time and the second time, between the third time and the fourth time, the greater the sum of the brake forces output by the brake system of the electric vehicle to the two right-side wheels. The greater the vehicle speed of the electric vehicle between the second time and the third time, the greater the sum of the brake forces output by the brake system to the two left-side wheels.

[0048] In another embodiment, the sum of the brake forces output by the brake system to the two left-side wheels increases with the increase of the accelerator pedal opening degree after the fifth time when the steering wheel starts to turn right and before the sixth time when the steering wheel starts to turn left. The sum of the brake forces output by the brake system of the electric vehicle to the two right-side wheels increases with the increase of the accelerator pedal opening degree after the sixth time and before the seventh time when the steering wheel starts to turn right. The sum of the brake forces output by the brake system to the two left-side wheels increases with the increase of the accelerator pedal opening degree after the seventh time and before the eighth time when the steering wheel turns right.

[0049] According to the scheme of the present application, during the emergency lane change of the electric vehicle, the size of the brake force output by the brake system to one side is determined according to the vehicle speed of the electric vehicle, so that the difference between the brake forces received by the wheels on both sides of the electric vehicle is within a suitable range, which can enable the electric vehicle to generate sufficient righting torque and more effectively correct the yaw of the electric vehicle, thereby improving the safety and stability of the emergency lane change of the electric vehicle.

[0050] In combination with the first aspect, in some implementations of the first aspect, the control method specifically includes, between the first time and the second time, between the third time and the fourth time, increasing the sum of the brake forces output by the brake system of the electric vehicle to the two right-side wheels with the increase of the turning angle or turning speed of the steering wheel. Between the second time and the third time, increasing the sum of the brake forces output by the brake system to the two left-side wheels with the increase of the turning angle or turning speed of the steering wheel.

[0051] The yaw angular velocity of the electric vehicle during the emergency lane change is also affected by the turning angle and turning speed of the steering wheel. The greater the turning angle of the steering wheel or the faster the turning speed of the steering wheel, the greater the change in the yaw angular velocity of the electric vehicle, and thus the electric vehicle needs greater righting torque to stabilize the electric vehicle. The greater the turning angle of the steering wheel or the faster the turning speed of the steering wheel, the greater the brake force output by the brake system to one side, and thus the greater the difference between the brake forces received by the wheels on both sides of the electric vehicle, which can enable the electric vehicle to generate greater righting torque.

[0052] According to the scheme of the application, during the emergency lane changing process of the electric vehicle, the size of the braking force output to one side by the braking system is determined according to the rotation angle or rotation speed of the steering wheel of the electric vehicle, so that the difference between the braking forces received by the wheels on both sides of the electric vehicle is within a suitable range, and the electric vehicle can generate sufficient righting moment, more effectively correct the yaw of the electric vehicle, and improve the safety and stability of the emergency lane changing of the electric vehicle.

[0053] In combination with the first aspect, in some implementations of the first aspect, the control method is specifically used in the lane changing process after the failure of the braking of one wheel of the electric vehicle, and the driving system is controlled to output positive torque in the same direction as the wheel speed or negative torque in the opposite direction as the wheel speed to the two rear wheels respectively to improve the stability of the electric vehicle during the lane changing process.

[0054] In the application, the failure of the braking of one wheel refers to that the wheel-end braking device for braking one wheel in the braking system cannot normally output the braking force to the one wheel. The causes of the failure of the braking of one wheel include actuator failure, braking motor failure, controller failure, and wheel speed sensor failure, etc. When the braking of the one wheel fails, the braking system cannot output the braking force to the one wheel, which will lead to the reduction of the braking effect of the braking system on one side of the electric vehicle and affect the safety and stability of the electric vehicle during the emergency lane changing process.

[0055] The existing electronic stability control system generates compensatory righting moment by applying braking force to a single wheel through the braking system during the emergency lane changing process of the electric vehicle, thereby effectively inhibiting the body yaw and making the actual driving path track the driver's intended path to the maximum extent. Therefore, when the braking of one wheel fails, the braking system cannot effectively control all the wheels, which is easy to lead to the loss of control of the electric vehicle during the emergency lane changing process.

[0056] When one wheel fails, the wheel-end braking device for braking the one wheel cannot output effective braking force. At this time, outputting negative torque to the one wheel through the control of the braking system can make up for the failure of the braking force, thereby realizing the function of the original electronic stability control system in stability control through the driving system.

[0057] According to the scheme of the application, when the braking of one wheel fails, negative torque is output to the wheel with the failure of the braking through the control of the driving system to make up for the failure of the braking force. During the emergency lane changing process of the electric vehicle, positive torque and negative torque are output to the two rear wheels through the driving system, so that the electric vehicle generates righting moment to perform yaw stability control, thereby correcting the yaw of the electric vehicle and ensuring the safety of the electric vehicle during the emergency lane changing. Even if the braking fails, the electric vehicle can still be controlled.

[0058] With reference to the first aspect, in some implementations of the first aspect, during the lane-changing process in which the right rear wheel of the electric vehicle is subject to brake failure, the control method specifically comprises, between the first time and the second time, between the third time and the fourth time, controlling the brake system to output a braking force of zero to the left front wheel, and controlling the brake system to output a braking force greater than zero to the right front wheel. Between the second time and the third time, the brake system is controlled to output a braking force of zero to the right front wheel, and the brake system is controlled to output a braking force greater than zero to the left front wheel.

[0059] When the wheel subject to brake failure is the right rear wheel, the brake system cannot output an effective braking force to the right rear wheel, so the brake system is controlled to adjust the braking forces output to the other three wheels in coordination with the drive system to perform stability control on the electric vehicle.

[0060] Between the first time and the second time, between the third time and the fourth time, the electric vehicle requires rightward correction, the brake system is controlled to output a braking force of zero to the left front wheel, and the brake system is controlled to output a braking force greater than zero to the right front wheel, so that the electric vehicle receives a greater braking force on the right side than on the left side, generating a rightward correction torque to correct the yaw of the electric vehicle. Between the second time and the third time, the electric vehicle requires leftward correction, the brake system is controlled to output a braking force of zero to the right front wheel, and the brake system is controlled to output a braking force greater than zero to the left front wheel, so that the electric vehicle receives a greater braking force on the left side than on the right side, generating a leftward correction torque to correct the yaw of the electric vehicle.

[0061] In another embodiment, after the fifth time when the steering wheel starts to turn right, before the sixth time when the steering wheel starts to turn left, the brake system is controlled to output a braking force of zero to the right front wheel, and the brake system is controlled to output a braking force greater than zero to the left front wheel. After the sixth time, before the seventh time when the steering wheel starts to correct rightward, the brake system is controlled to output a braking force of zero to the left front wheel, and the brake system is controlled to output a braking force greater than zero to the right front wheel. After the seventh time, before the eighth time when the steering wheel corrects rightward, the brake system is controlled to output a braking force of zero to the right front wheel, and the brake system is controlled to output a braking force greater than zero to the left front wheel.

[0062] In another embodiment, when the wheel subject to brake failure is the left rear wheel, during the lane-changing process in which the left rear wheel of the electric vehicle is subject to brake failure, the control method specifically comprises, between the first time and the second time, between the third time and the fourth time, controlling the brake system to output a braking force of zero to the left front wheel, and controlling the brake system to output a braking force greater than zero to the right front wheel. Between the second time and the third time, the brake system is controlled to output a braking force of zero to the right front wheel, and the brake system is controlled to output a braking force greater than zero to the left front wheel.

[0063] According to the scheme, in the emergency lane-changing process of the right rear wheel brake failure of the electric vehicle, even if the opening degree of the brake pedal does not change, by controlling the brake forces output by the brake system to the left and right wheels of the electric vehicle to be unequal, the electric vehicle generates a righting moment, effectively corrects the yaw of the electric vehicle, and improves the safety and stability of the emergency lane-changing of the electric vehicle.

[0064] In combination with the first aspect, in some implementations of the first aspect, the control method further includes controlling the brake system to output a brake force greater than zero to the left rear wheel between the second time and the third time.

[0065] The maximum braking effect that each wheel of the electric vehicle can achieve is fixed. The wheel can achieve braking by outputting a reverse torque through the drive system, can achieve braking by outputting a brake force through the brake system, and can achieve braking by outputting a reverse torque through the drive system in cooperation with the brake system outputting a brake force. The reverse torque output by the drive system is limited, so when the wheel does not reach the maximum braking effect, the brake force output by the brake system can be superimposed to improve the braking effect.

[0066] When the right rear wheel brake fails and the left rear wheel brake is normal, for the left rear wheel, the braking effect can be achieved by outputting a reverse torque through the drive system in cooperation with the brake system outputting a brake force. Between the second time and the third time, the brake system is controlled to output a brake force greater than zero to the left rear wheel, which cooperates with the reverse torque output by the drive system to the left rear wheel, so that the left rear wheel generates a larger braking effect, and the electric vehicle generates a righting moment, effectively correcting the yaw of the electric vehicle.

[0067] In another embodiment, after the fifth time when the steering wheel starts to turn to the right, before the sixth time when the steering wheel starts to turn to the left, the brake system is controlled to output a brake force greater than zero to the left rear wheel. After the seventh time, before the eighth time when the steering wheel returns to the right, the brake system is controlled to output a brake force greater than zero to the left rear wheel.

[0068] In another embodiment, when the brake failure wheel is the left rear wheel, between the first time and the second time, and between the third time and the fourth time, the brake system is controlled to output a brake force greater than zero to the right rear wheel.

[0069] According to the scheme, the brake force output by the brake system cooperates with the reverse torque output by the drive system, so that the wheel can reach the maximum braking effect, and the electric vehicle can generate a sufficient righting moment, more effectively correcting the yaw of the electric vehicle, and improving the safety and stability of the emergency lane-changing of the electric vehicle.

[0070] In combination with the first aspect, in some implementations of the first aspect, in the lane-changing process in which the right front wheel of the electric vehicle is subject to brake failure, the control method specifically comprises, between the first time and the second time, between the third time and the fourth time, controlling the drive system to output a reverse torque to the right rear wheel, and controlling the brake system to output a braking force of zero to the left front wheel. Between the second time and the third time, controlling the drive system to output a reverse torque to the left rear wheel, and controlling the brake system to output a braking force greater than zero to the left front wheel.

[0071] When the wheel subject to brake failure is the right front wheel, the brake system cannot output an effective braking force to the right front wheel, so the braking force output to the other three wheels is adjusted by the brake system in coordination with the drive system to perform stability control on the electric vehicle.

[0072] Between the first time and the second time, between the third time and the fourth time, the electric vehicle requires a rightward return, the brake system is controlled to output a braking force of zero to the left front wheel, and the drive system is controlled to output a reverse torque to the right rear wheel, thereby generating a rightward return moment to correct the yaw of the electric vehicle. Between the second time and the third time, the electric vehicle requires a leftward return, the brake system is controlled to output a braking force greater than zero to the left front wheel, so that the braking force on the left side of the electric vehicle is greater than that on the right side, thereby generating a leftward return moment to correct the yaw of the electric vehicle.

[0073] In another embodiment, after the fifth time when the steering wheel starts to turn right, before the sixth time when the steering wheel starts to turn left, the drive system is controlled to output a reverse torque to the left rear wheel, and the brake system is controlled to output a braking force greater than zero to the left front wheel. After the sixth time, before the seventh time when the steering wheel starts to return right, the drive system is controlled to output a reverse torque to the right rear wheel, and the brake system is controlled to output a braking force equal to zero to the left front wheel. After the seventh time, before the eighth time when the steering wheel returns, the drive system is controlled to output a reverse torque to the left rear wheel, and the brake system is controlled to output a braking force greater than zero to the left front wheel.

[0074] In another embodiment, when the wheel subject to brake failure is the left front wheel, in the lane-changing process in which the left front wheel of the electric vehicle is subject to brake failure, the control method specifically comprises, between the first time and the second time, between the third time and the fourth time, controlling the drive system to output a reverse torque to the right rear wheel, and controlling the brake system to output a braking force greater than zero to the right front wheel. Between the second time and the third time, controlling the drive system to output a reverse torque to the left rear wheel, and controlling the brake system to output a braking force equal to zero to the right front wheel.

[0075] According to the scheme of the application, in the emergency lane-changing process of the electric vehicle with the right rear wheel brake failure, even if the opening degree of the brake pedal does not change, the control of the brake system to output the braking forces to the left and right wheels of the electric vehicle is not equal, so that the electric vehicle generates a return torque, effectively corrects the yaw of the electric vehicle, and improves the safety and stability of the emergency lane-changing of the electric vehicle.

[0076] In combination with the first aspect, in some implementations of the first aspect, the control method further includes controlling the drive system to output reverse torques to the two front wheels after the first time.

[0077] Compared with the rear wheel brake failure, when the front wheel brake failure occurs, if the speed of the electric vehicle is large, the electric vehicle is more likely to lose control. Therefore, when the front wheel brake failure occurs, the control of the drive system to output reverse torques to the two front wheels can provide additional deceleration, so that the electric vehicle is more likely to be controlled.

[0078] According to the scheme of the application, in the emergency lane-changing process of the electric vehicle with the right rear wheel brake failure, the drive system is controlled to output reverse torques to the two front wheels, thereby providing additional deceleration, so that the return torque generated by the electric vehicle more effectively corrects the yaw of the electric vehicle, and improves the safety and stability of the emergency lane-changing of the electric vehicle.

[0079] In combination with the first aspect, in some implementations of the first aspect, the control method further includes controlling the brake system to output a braking force greater than zero to the right rear wheel between the first time and the second time, and between the third time and the fourth time. Between the second time and the third time, the brake system is controlled to output a braking force greater than zero to the left rear wheel.

[0080] When the right front wheel brake failure occurs, the brakes of the two rear wheels are normal, so for the two rear wheels, the reverse torques output by the drive system can be used to realize the braking effect together with the braking force output by the brake system. Between the first time and the second time, and between the third time and the fourth time, the brake system is controlled to output a braking force greater than zero to the right rear wheel, which cooperates with the reverse torque output by the drive system to the right rear wheel to make the right rear wheel generate a larger braking effect, so that the electric vehicle generates a return torque, effectively correcting the yaw of the electric vehicle. Between the second time and the third time, the brake system is controlled to output a braking force greater than zero, which cooperates with the reverse torque output by the drive system to the left rear wheel to make the left rear wheel generate a larger braking effect, so that the electric vehicle generates a return torque, effectively correcting the yaw of the electric vehicle.

[0081] In another embodiment, after a fifth time point when the steering wheel starts to turn right, before a sixth time point when the steering wheel starts to turn left, the control system controls the brake system to output a brake force greater than zero to the left rear wheel. After the sixth time point, before a seventh time point when the steering wheel starts to turn right back, the control system controls the brake system to output a brake force greater than zero to the right rear wheel, and controls the brake system to output a brake force greater than zero to the right front wheel. After the seventh time point, before an eighth time point when the steering wheel turns back, the control system controls the brake system to output a brake force greater than zero to the left rear wheel.

[0082] According to the scheme of the present application, the brake force output by the brake system matches the reverse torque output by the drive system, so that the wheels can achieve maximum braking effect, and the electric vehicle can generate sufficient turning back torque, which can more effectively correct the yaw of the electric vehicle, and improve the safety and stability of the electric vehicle in the process of emergency lane change.

[0083] In a second aspect, the present application provides a motor controller. The motor controller is used to control the drive system to output torque to two rear wheels of an electric vehicle, and the controller is specifically used to: After a first time point when the steering wheel starts to turn left, before a second time point when the steering wheel starts to turn right, the control system controls the drive system to output a positive torque to the left rear wheel and a reverse torque to the right rear wheel; After the second time point, before a third time point when the steering wheel starts to turn left back, the control system controls the drive system to output a reverse torque to the left rear wheel and a positive torque to the right rear wheel; After the third time point, before a fourth time point when the steering wheel turns back, the control system controls the drive system to output a positive torque to the left rear wheel and a reverse torque to the right rear wheel.

[0084] In a third aspect, the present application provides an electric vehicle, which comprises a motor controller as described in the second aspect, and a power battery, a drive system, a brake system and four wheels. The motor controller is used to receive power supply from the power battery and control the drive system to output torque to two rear wheels.

[0085] The beneficial effects of other aspects can refer to the beneficial effects described in the first aspect, which will not be described here. BRIEF DESCRIPTION OF DRAWINGS

[0086] Figure 1 is a schematic diagram of an electric vehicle provided by an embodiment of the present application; Figure 2 is a schematic diagram of a brake system architecture provided by an embodiment of the present application; Figure 3 is a schematic diagram of an electric vehicle architecture provided by an embodiment of the present application; Figure 4 is a schematic diagram of a drive system control in the process of emergency lane change provided by an embodiment of the present application; Figure 5 is a control schematic of a driving system and a braking system in an emergency lane-changing process provided by an embodiment of the present application; Figure 6 is a scenario schematic of an emergency lane-changing process provided by an embodiment of the present application; Figure 7 is a control schematic of a driving system and a braking system in an emergency lane-changing process provided by an embodiment of the present application; Figure 8 is another scenario schematic of an emergency lane-changing process provided by an embodiment of the present application; Figure 9 is another control schematic of a driving system and a braking system in an emergency lane-changing process provided by an embodiment of the present application; Figure 10 is a control flow schematic in an emergency lane-changing process of one wheel brake failure of an electric vehicle provided by an embodiment of the present application; Figure 11 is another control schematic of a driving system and a braking system in an emergency lane-changing process provided by an embodiment of the present application; Figure 12 is another scenario schematic of an emergency lane-changing process provided by an embodiment of the present application; Figure 13 is another control schematic of a driving system and a braking system in an emergency lane-changing process provided by an embodiment of the present application; Figure 14 is another scenario schematic of an emergency lane-changing process provided by an embodiment of the present application; Figure 15 is another control schematic of a driving system and a braking system in an emergency lane-changing process provided by an embodiment of the present application; Figure 16 is another scenario schematic of an emergency lane-changing process provided by an embodiment of the present application; Figure 17 is another control schematic of a driving system and a braking system in an emergency lane-changing process provided by an embodiment of the present application; Figure 18 is another scenario schematic of an emergency lane-changing process provided by an embodiment of the present application; Figure 19 is another control schematic of a driving system and a braking system in an emergency lane-changing process provided by an embodiment of the present application; Figure 20 is a control flow schematic in an emergency lane-changing process of two wheel brake failure of an electric vehicle provided by an embodiment of the present application; Figure 21 is another scenario schematic of an emergency lane-changing process provided by an embodiment of the present application; Figure 22is another driving system and brake system control schematic diagram in an emergency lane changing process provided by an embodiment of the present application; Figure 23 is another emergency lane changing process scenario schematic diagram provided by an embodiment of the present application; Figure 24 is another driving system and brake system control schematic diagram in an emergency lane changing process provided by an embodiment of the present application; Figure 25 is a control flow schematic diagram in an emergency lane changing process of three-wheel brake failure of an electric vehicle provided by an embodiment of the present application; Figure 26 is an emergency lane changing process signal transmission schematic diagram of an electric vehicle provided by an embodiment of the present application. DETAILED DESCRIPTION

[0087] The technical solutions in the present application will be described below with reference to the drawings. The detailed description of the following embodiments and the drawings are used to exemplarily illustrate the principles of the present application, but cannot be used to limit the scope of the present application, i.e., the present application is not limited to the described embodiments.

[0088] When an electric vehicle encounters a sudden situation such as an obstacle in front or a vehicle component failure out of control during high-speed driving, it needs to perform emergency lane changing, which is one of the most extreme tests for the stability of the electric vehicle. During emergency lane changing, the driver usually quickly and greatly turns the steering wheel, which is extremely easy to cause the vehicle center of gravity to shift sharply and break through the tire grip limit, so that understeering or more dangerous oversteering may occur, and the vehicle body may completely deviate from the predetermined route. The existing electronic stability system only relies on the brake system to control the electric vehicle in the emergency lane changing process, lacks control coordination, and once the brake system fails, the electric vehicle is easy to lose control.

[0089] Based on the above problems, the present application provides a control method, a motor controller and an electric vehicle for an electric vehicle. The driving system outputs reverse torque to one side wheel, so that differential torque is generated on both sides of the vehicle body, a compensatory righting moment is generated, and then the vehicle yaw is corrected, thereby ensuring the safety of the electric vehicle during lane changing and improving the safety and stability of the electric vehicle.

[0090] Figures 1-3 is a schematic diagram of an electric vehicle 10 architecture provided by an embodiment of the present application.

[0091] As Figure 1As shown, the electric vehicle 10 comprises a vehicle controller 20, a drive system 50 and a brake system 60, the drive system 50 comprises a motor controller 40 and a drive motor 30, the motor controller 40 is configured to output current to the drive motor 30 to control the drive motor 30 to output torque to drive the electric vehicle 10, the brake system 60 is configured to output braking force to brake four wheels of the electric vehicle 10.

[0092] As shown in Figure 2 , the brake system 60 comprises a brake pedal and four wheel-end brake devices. During the driving of the electric vehicle 10, when the electric vehicle 10 needs to be braked, the driver steps on the brake pedal, and the brake system 60 controls the four wheel-end brakes to output braking force to brake the electric vehicle 10.

[0093] The brake pedal in this application is also called brake or brake pedal. The opening degree of the brake pedal indicates the size of the braking force required by the driver, the larger the opening degree of the brake pedal, the greater the demand of the driver for braking, and the greater the braking force required by the brake system 60 to output. When the electric vehicle 10 is in normal driving, the brake system 60 controls the wheel-end brake device according to the opening degree of the brake pedal, so as to output the braking force indicated by the opening degree of the brake pedal, the larger the opening degree of the brake pedal, the greater the braking force output by the wheel-end brake device, and the smaller the opening degree of the brake pedal, the smaller the braking force output by the wheel-end brake device. The braking force output by the brake system 60 changes with the change of the opening degree of the brake pedal.

[0094] Exemplarily, the brake system comprises four wheel-end brake devices, and the four wheel-end brake devices comprise a wheel-end brake device 61, a wheel-end brake device 62, a wheel-end brake device 63 and a wheel-end brake device 64. The wheel-end brake device 61 is configured to brake the wheel 51, the wheel-end brake device 62 is configured to brake the wheel 52, the wheel-end brake device 63 is configured to brake the wheel 53, and the wheel-end brake device 64 is configured to brake the wheel 54.

[0095] In an embodiment, the electric vehicle 10 is a distributed four-drive motor driving architecture, and the drive motor is arranged on the driven wheel side and controlled by a separate motor controller 40. In an embodiment, the electric vehicle 10 is also a centralized drive motor driving architecture, and the drive motor for driving two front wheels or two rear wheels is arranged together. The motor controller 40 is one or more. The motor controller 40 is one-to-one corresponding to the drive motor, or one motor controller 40 corresponds to multiple drive motors. The motor controller 40 is configured to control one or more drive motors to output torque to drive the electric vehicle 10.

[0096] In an embodiment, as shown in (a) of Figure 3 , the electric vehicle 10 is a distributed four-drive motor driving architecture, and the drive motor is arranged on the driven wheel side and controlled by a separate motor controller. The electric vehicle 10 is also a centralized drive motor driving architecture as shown inFigure 3 The centralized four-motor drive architecture shown in (b) of FIG. 1A is used to drive two front wheels or two rear wheels. Two drive motors are set together.

[0097] For example, the electric vehicle 10 includes four motor controllers, including motor controller 41, motor controller 42, motor controller 43, and motor controller 44. The four motors include drive motor 31, drive motor 32, drive motor 33, and drive motor 34. The motor controller 41 controls the drive motor 31 to drive the wheel 51, the motor controller 42 controls the drive motor 32 to drive the wheel 52, the motor controller 43 controls the drive motor 33 to drive the wheel 53, and the motor controller 44 controls the drive motor 34 to drive the wheel 54.

[0098] In one embodiment, the electric vehicle 10 is also as shown in (c) of FIG. 1A, which is a centralized drive motor architecture, using one drive motor to drive two front wheels of the electric vehicle 10, and using two drive motors to drive two rear wheels of the electric vehicle 10. Figure 3

[0099] In one embodiment, the front drive can use the distributed drive motor architecture, and the rear drive can use the centralized drive motor architecture.

[0100] The electric vehicle 10 also includes an accelerator pedal and a steering wheel. The accelerator pedal is used to indicate the drive system to output positive torque to the wheels of the electric vehicle 10. The steering wheel is used to indicate the steering angle of the two front wheels.

[0101] The accelerator pedal in this application is also called a throttle pedal or a gas pedal. The opening of the accelerator pedal indicates the size of the driving force required by the driver. The larger the opening of the accelerator pedal, the greater the demand of the driver for driving, and the greater the torque required by the drive motor to output. The drive system controls the current output to the drive motor according to the opening of the accelerator pedal to make the drive motor output the torque indicated by the opening of the accelerator pedal. The larger the opening of the accelerator pedal, the greater the current and the greater the torque output by the drive motor. The smaller the opening of the accelerator pedal, the smaller the current and the smaller the torque output by the drive motor. The positive torque output by the drive system changes with the change of the opening of the accelerator pedal.

[0102] In one embodiment, each motor controller 40 is directly connected to the accelerator pedal and controls the corresponding drive motor to output torque according to the torque signal output by the accelerator pedal.

[0103] ​In an embodiment, each motor controller 40 is connected with a resolver sensor for detecting the rotating speed of the drive motor 30 controlled by the motor controller 40, and the motor controller 40 is configured to receive signals from the resolver sensor. The resolver sensor can accurately detect the position, direction and speed of the motor rotor, is responsible for monitoring and extracting the rotating speed of the drive motor, has a high sampling rate, and is directly connected with the motor controller 40, so that the signal transmission time is short and the stability is higher.

[0104] In an embodiment, the motor controller 40 further acquires the vehicle speed, yaw rate and center side slip angle of the electric vehicle 10 from the whole vehicle controller 20 or other sensors of the electric vehicle 10 through the signal interface.

[0105] The control method for the electric vehicle 10, the motor controller 40 and the electric vehicle 10 provided by the embodiments of the present application will be described below. Figures 4-10 Figure 4 、 Figure 5 、 Figure 7 and Figure 9 are signal timing diagrams of the electric vehicle 10 in the driving process, Figure 4 including the relationship between the drive system 50 and the steering wheel angle in the emergency lane changing process of the electric vehicle 10, Figure 5 、 Figure 7 and Figure 9 include the relationship between the drive system 50, the brake system 60 and the steering wheel angle in the emergency lane changing process of the electric vehicle 10. Figure 6 and Figure 8 are scene schematic diagrams of the electric vehicle 10 in the emergency lane changing process. Figure 10 is a control flow schematic diagram of the emergency lane changing process of a wheel brake failure of the electric vehicle.

[0106] The control method provided by the present application is used to improve the stability of the electric vehicle 10 in the lane changing process by controlling the drive system 50 to output positive torque with the same direction of wheel speed or reverse torque with the opposite direction of wheel speed to the two rear wheels.

[0107] As shown in Figure 4 , the control method includes controlling the drive system 50 to output positive torque to the left rear wheel and reverse torque to the right rear wheel after the first time t1 when the steering wheel starts to turn left and before the second time t2 when the steering wheel starts to turn right. After the second time t2 and before the third time t3 when the steering wheel starts to turn left, the drive system 50 is controlled to output reverse torque to the left rear wheel and positive torque to the right rear wheel. After the third time t3 and before the fourth time t4 when the steering wheel returns to the normal position, the drive system 50 is controlled to output positive torque to the left rear wheel and reverse torque to the right rear wheel.

[0108] ​When the electric vehicle 10 needs to change lanes in an emergency, for example, an obstacle appears on the driving route of the electric vehicle 10 and needs to be avoided, the driver will quickly turn the steering wheel to one side to make the electric vehicle 10 quickly change the driving route to change lanes to avoid the obstacle, and after entering the new road, the driver will immediately reverse the steering wheel to make the vehicle head of the electric vehicle 10 change to guide the driving route to the straightening route, and after the electric vehicle 10 passes the obstacle, the driver will turn the steering wheel to the other side, and the electric vehicle 10 will change lanes again. During the emergency lane change process, the path change of the vehicle completely depends on the friction between the tire and the ground, and the tire is extremely easy to reach the limit of the grip during the emergency lane change, resulting in the loss of control of the electric vehicle 10, so it is necessary to control the yaw of the electric vehicle 10 to improve the stability of driving, so that the electric vehicle 10 can change lanes as expected by the driver.

[0109] At the first time t1, the steering wheel starts to turn to the left, and the electric vehicle 10 changes lanes to the left. Since it is an emergency lane change, the electric vehicle 10 may turn too much. In order to ensure stability, it is necessary to make the electric vehicle 10 generate a right straightening moment. At this time, the control driving system 50 outputs positive torque to the left rear wheel and outputs reverse torque to the right rear wheel, so that for the two wheels of the rear axle, the left wheel receives positive torque and the right wheel receives reverse torque, so that the torques received by the left and right sides are different, which will make the vehicle generate a right straightening moment to improve the stability of the electric vehicle 10.

[0110] At the second time t2, the steering wheel starts to turn to the right, and the driver reverses the steering wheel to correct the yaw of the electric vehicle 10, which needs to make the electric vehicle 10 generate a left straightening moment. At this time, the control driving system 50 outputs reverse torque to the left rear wheel and outputs positive torque to the right rear wheel, so that for the two wheels of the rear axle, the left wheel receives reverse torque and the right wheel receives positive torque, so that the torques received by the left and right sides are different, which will make the vehicle generate a left straightening moment to straighten the electric vehicle 10.

[0111] At the third time t3, the steering wheel starts to turn to the left, and the electric vehicle 10 changes lanes from the left lane again after passing the obstacle, which needs to make the electric vehicle 10 generate a right straightening moment. At this time, the control driving system 50 outputs reverse torque to the left rear wheel and outputs positive torque to the right rear wheel, so that for the two wheels of the rear axle, the left wheel receives positive torque and the right wheel receives reverse torque, so that the torques received by the left and right sides are different, which will make the vehicle generate a right straightening moment to improve the stability of the electric vehicle 10.

[0112] In another embodiment, after the fifth time when the steering wheel starts to turn right, before the sixth time when the steering wheel starts to turn left, the control system controls the drive system 50 to output positive torque to the right rear wheel and output negative torque to the left rear wheel. After the sixth time, before the seventh time when the steering wheel starts to turn right, the control system controls the drive system 50 to output negative torque to the right rear wheel and output positive torque to the left rear wheel. After the seventh time, before the eighth time when the steering wheel turns right, the control system controls the drive system 50 to output positive torque to the right rear wheel and output negative torque to the left rear wheel.

[0113] It should be understood that, because the drive system 50 needs to output torque to the two rear wheels respectively, the drive system 50 includes multiple drive motors 30, the two front wheels are driven by at least one drive motor 30, and the two rear wheels are driven by two drive motors 30.

[0114] According to the scheme of the present application, during the emergency lane changing process of the electric vehicle 10, the drive system 50 outputs positive torque and negative torque to the two rear wheels respectively, so that the electric vehicle 10 generates a righting moment for yaw stability control, thereby correcting the yaw of the electric vehicle 10, and ensuring the safety of the electric vehicle 10 during emergency lane changing.

[0115] In one embodiment, the control method further comprises, before the first time t1, during driving with no steering wheel turning, controlling the drive system 50 to output positive torque to the two rear wheels. After the fourth time t4, during driving with no steering wheel turning, controlling the drive system 50 to output positive torque to the two rear wheels.

[0116] Before the first time t1, the electric vehicle 10 is driving straight, the steering wheel is not turning, and at this time the drive system 50 outputs positive torque to the two rear wheels to drive the electric vehicle 10.

[0117] After the fourth time t4, the electric vehicle 10 has completed the emergency obstacle avoidance lane changing process and returned to the straight driving state, the steering wheel is not turning, and at this time the drive system 50 outputs positive torque to the two rear wheels to drive the electric vehicle 10.

[0118] In one embodiment, the control method further comprises, between the first time t1 and the second time t2, between the third time t3 and the fourth time t4, controlling the drive system 50 to output positive torque to the left rear wheel that varies with the opening degree of the accelerator pedal. Between the second time t2 and the third time t3, controlling the drive system 50 to output positive torque to the right rear wheel that varies with the opening degree of the accelerator pedal.

[0119] During the emergency lane changing process, the drive system 50 outputs positive torque to the steering side wheel indicated by the opening degree of the accelerator pedal, and the magnitude of the positive torque varies with the opening degree of the accelerator pedal.

[0120] In another embodiment, after the fifth time when the steering wheel starts to turn right, before the sixth time when the steering wheel starts to turn left, the control system 50 controls the drive system 50 to output positive torque to the right rear wheel, which varies with the opening degree of the accelerator pedal. After the sixth time, before the seventh time when the steering wheel starts to turn right, the control system 50 controls the drive system 50 to output positive torque to the left rear wheel, which varies with the opening degree of the accelerator pedal. After the seventh time, before the eighth time when the steering wheel turns right, the control system 50 controls the drive system 50 to output positive torque to the right rear wheel, which varies with the opening degree of the accelerator pedal.

[0121] In one embodiment, the control method further comprises, between the first time t1 and the second time t2, when it is detected that the turning angle of the steering wheel is greater than a preset angle, or the turning speed is greater than a preset speed, or the yaw rate of the electric vehicle 10 is greater than a preset yaw rate, the control system 50 controls the drive system 50 to output reverse torque to the right rear wheel.

[0122] At the first time t1, the steering wheel starts to turn left, and the electric vehicle 10 determines whether the electric vehicle 10 performs emergency lane changing according to the turning angle of the steering wheel. When the driver needs to perform emergency lane changing, the driver usually turns the steering wheel to one side by a large angle, so when the turning angle of the steering wheel is greater than a preset angle, the control system 50 controls the drive system 50 to output reverse torque to the right rear wheel.

[0123] The preset angle is pre-calibrated according to real vehicle experiments and / or model calculations, or is pre-set by comprehensively considering the overall vehicle demand and vehicle performance.

[0124] At the first time t1, the steering wheel starts to turn left, and the electric vehicle 10 determines whether the electric vehicle 10 performs emergency lane changing according to the turning speed of the steering wheel. When the driver needs to perform emergency lane changing, the driver usually turns the steering wheel to one side quickly, so when the turning speed of the steering wheel is greater than a preset speed, the control system 50 controls the drive system 50 to output reverse torque to the right rear wheel.

[0125] The preset speed is pre-calibrated according to real vehicle experiments and / or model calculations, or is pre-set by comprehensively considering the overall vehicle demand and vehicle performance.

[0126] At the first time t1, the steering wheel starts to turn left, and the electric vehicle 10 determines whether the electric vehicle 10 performs emergency lane changing according to the yaw rate. When the electric vehicle 10 performs emergency lane changing, the direction changes rapidly, and the yaw rate rises quickly, so when the yaw rate is greater than a preset yaw rate, the control system 50 controls the drive system 50 to output reverse torque to the right rear wheel.

[0127] The preset yaw rate is pre-calibrated according to real vehicle experiments and / or model calculations, or is pre-set by comprehensively considering the overall vehicle demand and vehicle performance.

[0128] In another embodiment, after the fifth time when the steering wheel starts to turn right, before the sixth time when the steering wheel starts to turn left, the control system controls the driving system 50 to output a reverse torque to the left rear wheel when the turning angle of the steering wheel is greater than a preset angle, or the turning speed is greater than a preset speed, or the yaw rate of the electric vehicle 10 is greater than a preset yaw rate.

[0129] In one embodiment, the control method specifically comprises increasing the reverse torque output by the driving system 50 to the right rear wheel with the increase of the opening degree of the accelerator pedal between the first time t1 and the second time t2, and between the third time t3 and the fourth time t4. The reverse torque output by the driving system 50 to the left rear wheel is increased with the increase of the opening degree of the accelerator pedal between the second time t2 and the third time t3.

[0130] The yaw rate of the electric vehicle 10 during the emergency lane changing process is affected by the vehicle speed of the electric vehicle 10. The faster the vehicle speed, the greater the change of the yaw rate, and thus the electric vehicle 10 needs a greater return torque to stabilize the electric vehicle 10. If the driver steps on the accelerator pedal, the vehicle speed of the electric vehicle 10 will change. At this time, the size of the reverse torque output to the rear wheel is determined according to the opening degree of the accelerator pedal.

[0131] In one implementation, the greater the vehicle speed of the electric vehicle 10, the greater the reverse torque output by the driving system 50 to the right rear wheel between the first time t1 and the second time t2, and between the third time t3 and the fourth time t4. The greater the vehicle speed of the electric vehicle 10, the greater the reverse torque output by the driving system 50 to the left rear wheel between the second time t2 and the third time t3.

[0132] In another embodiment, after the fifth time when the steering wheel starts to turn right, before the sixth time when the steering wheel starts to turn left, the control system controls the driving system 50 to increase the reverse torque output to the left rear wheel with the increase of the opening degree of the accelerator pedal. After the sixth time, before the seventh time when the steering wheel starts to turn right, the control system controls the driving system 50 to increase the reverse torque output to the right rear wheel with the increase of the opening degree of the accelerator pedal. After the seventh time, before the eighth time when the steering wheel turns right, the control system controls the driving system 50 to increase the reverse torque output to the left rear wheel with the increase of the opening degree of the accelerator pedal.

[0133] In one embodiment, the control method specifically comprises increasing the reverse torque output by the driving system 50 to the right rear wheel with the increase of the turning angle or turning speed of the steering wheel between the first time t1 and the second time t2, and between the third time t3 and the fourth time t4. The reverse torque output by the driving system 50 to the left rear wheel is increased with the increase of the turning angle or turning speed of the steering wheel between the second time t2 and the third time t3.

[0134] The yaw rate of the electric vehicle 10 during the emergency lane-changing process is also affected by the steering wheel rotation angle and the rotation speed. The greater the steering wheel rotation angle or the faster the steering wheel rotation speed, the greater the change in the yaw rate of the electric vehicle 10, and thus the greater the return torque required by the electric vehicle 10 to stabilize the electric vehicle 10. The greater the steering wheel rotation angle or the faster the steering wheel rotation speed, the greater the reverse torque output by the drive system 50 to the rear wheels, and thus the greater the torque difference generated by the two rear wheels, which can enable the electric vehicle 10 to generate a greater return moment.

[0135] In an embodiment, as shown in FIG. 1, the control method further comprises, between the first time t1 and the second time t2, between the third time t3 and the fourth time t4, controlling the drive system 50 to output a torque difference between the two right wheels and the two left wheels of the electric vehicle 10, and controlling the brake system 60 to output a brake force difference between the two right wheels and the two left wheels of the electric vehicle 10. Figure 5

[0136] The control method is further used to improve the stability of the electric vehicle 10 during the lane-changing process by controlling the drive system 50 to adjust the torque output to the two rear wheels and controlling the brake system 60 to adjust the brake force output to the four wheels.

[0137] The brake system 60 comprises four wheel-end brake devices, each of which is used to output a brake force to a wheel of the electric vehicle 10. The four wheel-end brake devices correspond one-to-one to the four wheels, and the four wheel-end brake devices are used to output brake forces respectively. In a normal state, the four wheel-end brake devices are used to output brake forces indicated by the opening degree of the brake pedal.

[0138] Between the first time t1 and the second time t2, between the third time t3 and the fourth time t4, the return demand of the electric vehicle 10 is to the right, and the brake system 60 is controlled to output a brake force sum to the two right wheels that is greater than a brake force sum output to the two left wheels, so that the brake forces received by the two sides of the electric vehicle 10 are not equal, a return moment is generated to correct the yaw of the electric vehicle 10. Between the second time t2 and the third time t3, the return demand of the electric vehicle 10 is to the left, and the brake system 60 is controlled to output a brake force sum to the two right wheels that is less than a brake force sum output to the two left wheels, so that the brake forces received by the two sides of the electric vehicle 10 are not equal, a return moment is generated to correct the yaw of the electric vehicle 10.

[0139] ​In another embodiment, after the fifth time when the steering wheel starts to turn right, before the sixth time when the steering wheel starts to turn left, the control system 60 controls the brake system 60 to output a larger total brake force to the two left wheels than to the two right wheels. After the sixth time, before the seventh time when the steering wheel starts to turn right, the control system 60 controls the brake system 60 of the electric vehicle 10 to output a larger total brake force to the two right wheels than to the two left wheels. After the seventh time, before the eighth time when the steering wheel turns right, the control system 60 controls the brake system 60 to output a larger total brake force to the two left wheels than to the two right wheels.

[0140] In one embodiment, the control method specifically comprises, between the first time tl and the second time t2, between the third time t3 and the fourth time t4, controlling the brake system 60 of the electric vehicle 10 to increase the total brake force output to the two right wheels with the increase of the accelerator pedal opening. Between the second time t2 and the third time t3, controlling the brake system 60 to increase the total brake force output to the two left wheels with the increase of the accelerator pedal opening.

[0141] The yaw rate of the electric vehicle 10 during the emergency lane change process is affected by the speed of the electric vehicle 10, the faster the speed, the greater the change of the yaw rate, so the electric vehicle 10 needs a larger righting torque to stabilize the electric vehicle 10, and if the driver steps on the accelerator pedal, the speed of the electric vehicle 10 will change, at this time, the size of the brake force output by the brake system 60 to the wheels on one side is determined according to the size of the accelerator pedal opening.

[0142] In one implementation, between the first time tl and the second time t2, between the third time t3 and the fourth time t4, the greater the speed of the electric vehicle 10, the greater the total brake force output by the brake system 60 of the electric vehicle 10 to the two right wheels. Between the second time t2 and the third time t3, the greater the speed of the electric vehicle 10, the greater the total brake force output by the brake system 60 to the two left wheels.

[0143] In another embodiment, after the fifth time when the steering wheel starts to turn right, before the sixth time when the steering wheel starts to turn left, the control system 60 controls the brake system 60 to increase the total brake force output to the two left wheels with the increase of the accelerator pedal opening. After the sixth time, before the seventh time when the steering wheel starts to turn right, the control system 60 controls the brake system 60 of the electric vehicle 10 to increase the total brake force output to the two right wheels with the increase of the accelerator pedal opening. After the seventh time, before the eighth time when the steering wheel turns right, the control system 60 controls the brake system 60 to increase the total brake force output to the two left wheels with the increase of the accelerator pedal opening.

[0144] In an embodiment, the control method specifically comprises increasing the sum of the braking forces output by the braking system 60 to the two right-side wheels of the electric vehicle 10 with the increase of the steering wheel rotation angle or rotation speed between the first time t1 and the second time t2, and between the third time t3 and the fourth time t4. The sum of the braking forces output by the braking system 60 to the two left-side wheels is increased with the increase of the steering wheel rotation angle or rotation speed between the second time t2 and the third time t3.

[0145] The yaw rate of the electric vehicle 10 during the emergency lane-changing process is also affected by the steering wheel rotation angle and rotation speed. The greater the steering wheel rotation angle or the faster the steering wheel rotation speed, the greater the change of the yaw rate of the electric vehicle 10, and thus the greater the return torque required by the electric vehicle 10 to stabilize the electric vehicle 10. The greater the steering wheel rotation angle or the faster the steering wheel rotation speed, the greater the braking force output by the braking system 60 to one side, and thus the greater the difference in braking force between the wheels of the electric vehicle 10 on both sides, which can generate a greater return torque for the electric vehicle 10.

[0146] In an embodiment, the control method is specifically used in the lane-changing process after the failure of the braking of one wheel of the electric vehicle 10, to control the driving system 50 to output positive torque in the same direction as the wheel speed or negative torque in the opposite direction to the wheel speed to the two rear wheels respectively, so as to improve the stability of the electric vehicle 10 during the lane-changing process.

[0147] The failure of the braking system 60 includes various cases, such as single-wheel braking failure, double-wheel braking failure, and triple-wheel braking failure. In this application, the failure of the braking of one wheel of the electric vehicle 10 refers to the failure of the wheel-end braking device for braking one wheel of the electric vehicle 10 to normally output braking force to the one wheel. The causes of the failure of the braking of one wheel of the electric vehicle 10 include actuator failure, braking motor failure, controller failure, and wheel speed sensor failure, etc. When the braking of the one wheel of the electric vehicle 10 fails, the braking system 60 cannot output braking force to the one wheel, which will result in the reduction of the braking effect of the braking system 60 on one side of the electric vehicle 10, and affect the safety and stability of the electric vehicle 10 during the emergency lane-changing process.

[0148] The existing electronic stability control system generates a compensatory return torque by applying braking force to a single wheel of the electric vehicle 10 during the emergency lane-changing process of the electric vehicle 10, so as to effectively suppress the body yaw, and make the actual driving path track the driver's intended path to the maximum extent. Therefore, when the braking of one wheel of the electric vehicle 10 fails, the braking system 60 cannot effectively control all the wheels, which is easy to cause the electric vehicle 10 to lose control during the emergency lane-changing process.

[0149] When one wheel fails, the wheel end brake device for braking the one wheel cannot output effective braking force, at this time, by controlling the brake system 60 to output reverse torque to the one wheel, the lack of braking force can be made up, so that the function of the original electronic stability control system in stability control is realized through the driving system 50.

[0150] According to the scheme of the present application, when the braking of one wheel fails, by controlling the driving system 50 to output reverse torque to the wheel where the braking fails to make up for the failure of braking, in the process of emergency lane changing of the electric vehicle 10, by controlling the driving system 50 to output positive torque and reverse torque to the two rear wheels respectively, the electric vehicle 10 generates a righting moment to perform yaw stability control, thereby correcting the yaw of the electric vehicle 10, ensuring the safety of the electric vehicle 10 during emergency lane changing, and even if braking failure occurs, the electric vehicle 10 can still be controlled.

[0151] In one embodiment, as shown in Figure 6 and Figure 7 , in the process of lane changing with the right rear wheel of the electric vehicle 10 braking failure, the control method specifically includes controlling the brake system 60 to output braking force of zero to the left front wheel and controlling the brake system 60 to output braking force greater than zero to the right front wheel between the first time t1 and the second time t2, and between the third time t3 and the fourth time t4. Between the second time t2 and the third time t3, the brake system 60 is controlled to output braking force of zero to the right front wheel and the brake system 60 is controlled to output braking force greater than zero to the left front wheel.

[0152] When the wheel where the braking fails is the right rear wheel, the brake system 60 cannot output effective braking force to the right rear wheel, so by controlling the brake system 60 to adjust the braking force output to the other three wheels, the driving system 50 cooperates to perform stability control on the electric vehicle 10.

[0153] Between the first time t1 and the second time t2, and between the third time t3 and the fourth time t4, the righting demand of the electric vehicle 10 is to the right, the brake system 60 is controlled to output braking force of zero to the left front wheel, and the brake system 60 is controlled to output braking force greater than zero to the right front wheel, so that the braking force received by the right side of the electric vehicle 10 is greater than the braking force received by the left side, generating a rightward righting moment to correct the yaw of the electric vehicle 10. Between the second time t2 and the third time t3, the righting demand of the electric vehicle 10 is to the left, the brake system 60 is controlled to output braking force of zero to the right front wheel, and the brake system 60 is controlled to output braking force greater than zero to the left front wheel, so that the braking force received by the left side of the electric vehicle 10 is greater than the braking force received by the right side, generating a leftward righting moment to correct the yaw of the electric vehicle 10.

[0154] In another embodiment, after the fifth time when the steering wheel starts to turn right, before the sixth time when the steering wheel starts to turn left, the control method controls the brake system 60 to output zero braking force to the right front wheel and controls the brake system 60 to output braking force greater than zero to the left front wheel. After the sixth time, before the seventh time when the steering wheel starts to turn right, the control method controls the brake system 60 to output zero braking force to the left front wheel and controls the brake system 60 to output braking force greater than zero to the right front wheel. After the seventh time, before the eighth time when the steering wheel turns right, the control method controls the brake system 60 to output zero braking force to the right front wheel and controls the brake system 60 to output braking force greater than zero to the left front wheel.

[0155] In another embodiment, when the left rear wheel is the wheel whose brake fails, during the lane changing process of the left rear wheel of the electric vehicle 10, the control method specifically includes controlling the brake system 60 to output zero braking force to the left front wheel and controlling the brake system 60 to output braking force greater than zero to the right front wheel between the first time t1 and the second time t2 and between the third time t3 and the fourth time t4. Between the second time t2 and the third time t3, the control method controls the brake system 60 to output zero braking force to the right front wheel and controls the brake system 60 to output braking force greater than zero to the left front wheel.

[0156] In an embodiment, the control method further includes controlling the brake system 60 to output braking force greater than zero to the left rear wheel between the second time t2 and the third time t3.

[0157] The maximum braking effect that each wheel of the electric vehicle 10 can achieve is fixed. The wheel can achieve braking through the drive system 50 outputting reverse torque, can achieve braking through the brake system 60 outputting braking force, and can achieve braking through the drive system 50 outputting reverse torque together with the brake system 60 outputting braking force. The reverse torque output by the drive system 50 is limited, so when the wheel does not reach the maximum braking effect, the braking force output by the brake system 60 can be superimposed to improve the braking effect.

[0158] When the right rear wheel's brake fails and the left rear wheel's brake is normal, for the left rear wheel, the braking effect can be achieved through the drive system 50 outputting reverse torque together with the brake system 60 outputting braking force. Between the second time t2 and the third time t3, the control method controls the brake system 60 to output braking force greater than zero to the left rear wheel, which cooperates with the reverse torque output by the drive system 50 to the left rear wheel to make the left rear wheel produce a larger braking effect, so that the electric vehicle 10 produces a righting moment, effectively correcting the yaw of the electric vehicle 10.

[0159] In another embodiment, after the fifth time when the steering wheel starts to turn right, before the sixth time when the steering wheel starts to turn left, the control system 60 controls the brake system 60 to output a brake force greater than zero to the left rear wheel. After the seventh time, before the eighth time when the steering wheel returns to the straight position, the control system 60 controls the brake system 60 to output a brake force greater than zero to the left rear wheel.

[0160] In another embodiment, when the wheel with brake failure is the left rear wheel, between the first time t1 and the second time t2, between the third time t3 and the fourth time t4, the control system 60 controls the brake system 60 to output a brake force greater than zero to the right rear wheel.

[0161] In one embodiment, as shown in FIG. 1, the control method specifically includes, during the lane changing process when the right front wheel of the electric vehicle 10 has brake failure, between the first time t1 and the second time t2, between the third time t3 and the fourth time t4, controlling the drive system 50 to output a reverse torque to the right rear wheel, and controlling the brake system 60 to output a brake force of zero to the left front wheel. Between the second time t2 and the third time t3, the control system 50 controls the drive system 50 to output a reverse torque to the left rear wheel, and controls the brake system 60 to output a brake force greater than zero to the left front wheel. Figure 8 Figure 9 In another embodiment, when the wheel with brake failure is the left rear wheel, between the first time t1 and the second time t2, between the third time t3 and the fourth time t4, the control system 60 controls the brake system 60 to output a brake force greater than zero to the right rear wheel.

[0162] When the wheel with brake failure is the right front wheel, the brake system 60 cannot output an effective brake force to the right front wheel, so the control system 60 adjusts the brake forces output to the other three wheels in coordination with the drive system 50 to perform stability control on the electric vehicle 10.

[0163] Between the first time t1 and the second time t2, between the third time t3 and the fourth time t4, the return demand of the electric vehicle 10 is to the right, the control system 60 controls the brake system 60 to output a brake force of zero to the left front wheel, and the drive system 50 outputs a reverse torque to the right rear wheel to generate a right return moment to correct the yaw of the electric vehicle 10. Between the second time t2 and the third time t3, the return demand of the electric vehicle 10 is to the left, the control system 60 controls the brake system 60 to output a brake force greater than zero to the left front wheel, so that the brake force on the left side of the electric vehicle 10 is greater than the brake force on the right side, generating a left return moment to correct the yaw of the electric vehicle 10.

[0164] ​In another embodiment, after a fifth time instant at which the steering wheel starts to turn right, before a sixth time instant at which the steering wheel starts to turn left, the control system controls the drive system 50 to output a reverse torque to the left rear wheel and controls the brake system 60 to output a braking force greater than zero to the left front wheel. After the sixth time instant, before a seventh time instant at which the steering wheel starts to turn right back, the control system controls the drive system 50 to output a reverse torque to the right rear wheel and controls the brake system 60 to output a braking force equal to zero to the left front wheel. After the seventh time instant, before an eighth time instant at which the steering wheel turns back, the control system controls the drive system 50 to output a reverse torque to the left rear wheel and controls the brake system 60 to output a braking force greater than zero to the left front wheel.

[0165] In another embodiment, when the failed wheel is the left front wheel, the control method comprises, during the lane change with the left front wheel of the electric vehicle 10 being failed, between the first time instant tl and the second time instant t2, between the third time instant t3 and the fourth time instant t4, controlling the drive system 50 to output a reverse torque to the right rear wheel and controlling the brake system 60 to output a braking force greater than zero to the right front wheel. Between the second time instant t2 and the third time instant t3, the control system controls the drive system 50 to output a reverse torque to the left rear wheel and controls the brake system 60 to output a braking force equal to zero to the right front wheel.

[0166] In an embodiment, the control method further comprises, after the first time instant tl, controlling the drive system 50 to output a reverse torque to both front wheels.

[0167] When the front wheels are failed, the electric vehicle 10 is more likely to lose control if the speed of the electric vehicle 10 is high, compared to when the rear wheels are failed. Therefore, when the front wheels are failed, controlling the drive system 50 to output a reverse torque to both front wheels provides an additional deceleration, which makes the electric vehicle 10 more likely to be controlled.

[0168] In an embodiment, the control method further comprises, between the first time instant tl and the second time instant t2, between the third time instant t3 and the fourth time instant t4, controlling the brake system 60 to output a braking force greater than zero to the right rear wheel. Between the second time instant t2 and the third time instant t3, the control system controls the brake system 60 to output a braking force greater than zero to the left rear wheel.

[0169] When the right front wheel brake fails, the two rear wheel brakes are normal, so for the two rear wheels, the reverse torque output by the drive system 50 can be combined with the brake force output by the brake system 60 to achieve the braking effect. Between the first time t1 and the second time t2, between the third time t3 and the fourth time t4, the brake system 60 is controlled to output a brake force greater than zero to the right rear wheel, which is combined with the reverse torque output by the drive system 50 to the right rear wheel, so that the right rear wheel produces a larger braking effect, and the electric vehicle 10 generates a return torque, effectively correcting the yaw of the electric vehicle 10. Between the second time t2 and the third time t3, the brake system 60 is controlled to output a brake force greater than zero, which is combined with the reverse torque output by the drive system 50 to the left rear wheel, so that the left rear wheel produces a larger braking effect, and the electric vehicle 10 generates a return torque, effectively correcting the yaw of the electric vehicle 10.

[0170] In another embodiment, after the fifth time when the steering wheel starts to turn right, before the sixth time when the steering wheel starts to turn left, the brake system 60 is controlled to output a brake force greater than zero to the left rear wheel. After the sixth time, before the seventh time when the steering wheel starts to turn right, the brake system 60 is controlled to output a brake force greater than zero to the right rear wheel, and the brake system 60 is controlled to output a brake force greater than zero to the right front wheel. After the seventh time, before the eighth time when the steering wheel turns right, the brake system 60 is controlled to output a brake force greater than zero to the left rear wheel.

[0171] As shown in Figure 10 and Figure 26 , when the electric vehicle 10 performs an emergency lane change, the return demand is calculated according to the driving state of the electric vehicle 10, and the electric vehicle 10 is controlled according to the braking capacity of each wheel. When one wheel brake fails, the drive system 50 and the brake system 60 are controlled differently according to the direction of the return and the position of the failed wheel. The vehicle state signal includes the speed, acceleration, yaw rate, steering wheel signal, wheel speed signal and load information of the electric vehicle 10. The specific control method is described above and will not be repeated here.

[0172] The following Figures 11-20 Another control method for the electric vehicle 10, motor controller 4050 and electric vehicle 10 provided by the embodiment of the application will be described. Figure 11 、 Figure 13 、 Figure 15 、 Figure 17 and Figure 19 is a signal timing diagram of the electric vehicle 10 during driving, Figure 11 、 Figure 13 、 Figure 15 、 Figure 17 and Figure 19The control method includes the relationship between the driving system 50, the braking system 60 and the steering wheel angle during the emergency lane change process of the electric vehicle 10. Figure 12 , Figure 14 , Figure 16 and Figure 18 is a schematic diagram of the scenario of the electric vehicle 10 during the emergency lane change process. Figure 20 is a schematic diagram of the control flow during the emergency lane change process of the electric vehicle 10 when the two wheels of the electric vehicle 10 lose braking.

[0173] The control method is used to control the driving system 50 and the braking system 60 to improve the stability of the electric vehicle 10 during the lane change process.

[0174] As shown in Figure 10 , the control method includes controlling the braking system 60 to output zero braking force and controlling the driving system 50 to output positive torque to the four wheels indicated by the opening degree of the accelerator pedal before the steering wheel is turned to one side, the positive torque being in the same direction as the wheel speed. After the steering wheel is turned to one side, the driving system 50 is first controlled to output positive torque to the rear wheel on one side and negative torque to the rear wheel on the other side; then the braking system 60 is controlled to output braking force greater than zero to the front wheel on the other side or the driving system 50 is controlled to output negative torque to the front wheel on the other side, the negative torque being opposite to the direction of the speed.

[0175] Before the steering wheel is turned to one side, the electric vehicle 10 travels straight, the driver steps on the accelerator pedal, and the electric vehicle 10 controls the braking system 60 to output zero braking force and controls the driving system 50 to output positive torque to the four wheels indicated by the opening degree of the accelerator pedal to drive the electric vehicle 10.

[0176] When the electric vehicle 10 needs to change lanes in an emergency, for example, an obstacle appears on the driving route of the electric vehicle 10 and needs to be avoided, the driver will quickly turn the steering wheel to one side to quickly change the driving route of the electric vehicle 10 to change lanes to avoid the obstacle, and immediately after entering the new road, the driver will reverse the steering wheel to change the heading of the electric vehicle 10 to guide the driving route to the straight route, and after the electric vehicle 10 passes the obstacle, the driver will turn the steering wheel to the other side, and the electric vehicle 10 will change lanes again. During the emergency lane change process, the path change of the vehicle completely depends on the friction between the tire and the ground, and the tire is extremely easy to reach the limit of the grip force during the emergency lane change, causing the electric vehicle 10 to lose control, so the yaw of the electric vehicle 10 needs to be controlled to improve the stability of the driving to enable the electric vehicle 10 to change lanes as expected by the driver.

[0177] After the steering wheel is turned to one side, the electric vehicle 10 performs lane changing to one side. Since it is emergency lane changing, the electric vehicle 10 can turn too much, and in order to ensure stability, a return torque to the other side needs to be generated for the electric vehicle 10. At this time, the driving system 50 is first controlled to output positive torque to the rear wheel on one side and output reverse torque to the rear wheel on the other side, so that for the two wheels of the rear axle, the wheel on one side receives positive torque and the wheel on the other side receives reverse torque, so that the torque received by the left and right sides is different, which causes the electric vehicle 10 to generate a return torque to the other side and thus improve the stability of the electric vehicle 10. By outputting longitudinal torque and reverse torque to the rear wheels, the torque of the left and right wheels is reasonably distributed, which can correct the yaw of the electric vehicle 10. Further, the braking system 60 is further controlled to output brake force greater than zero to the front wheel on the other side. By outputting brake force to the front wheel on the other side through the braking system 60, for the two front wheels of the front axle, the brake force received by the wheel on one side is zero, and the brake force received by the wheel on the other side is greater than zero, so that the brake force received by the left and right sides is different, which causes the electric vehicle 10 to generate a return torque to the other side and thus improve the stability of the electric vehicle 10. Alternatively, the driving system 50 is controlled to output reverse torque to the front wheel on the other side, and the wheel can output brake force through the braking system 60 to achieve braking, or output reverse torque through the driving system 50 to achieve braking.

[0178] According to the scheme of the present application, during the emergency lane changing of the electric vehicle 10, the driving system 50 outputs positive torque and reverse torque to the two rear wheels respectively, and the braking system 60 outputs brake force to the front wheel, so that the electric vehicle 10 generates a return torque to correct the yaw of the electric vehicle 10 and ensure the safety of the electric vehicle 10 during emergency lane changing.

[0179] In an embodiment, the control method further comprises, after the steering wheel is turned to one side, when it is detected that the turning angle of the steering wheel is greater than a preset angle, or the turning speed is greater than a preset speed, or the yaw angular velocity of the electric vehicle 10 is greater than a preset angular velocity, first controlling the driving system 50 to output positive torque to the rear wheel on one side and output reverse torque to the rear wheel on the other side, and then controlling the braking system 60 to output brake force greater than zero to the front wheel on the other side, or controlling the driving system 50 to output reverse torque to the front wheel on the other side.

[0180] After the steering wheel is turned to one side, the electric vehicle 10 determines whether the electric vehicle 10 performs emergency lane changing according to the turning angle of the steering wheel. When the driver needs to perform emergency lane changing, the driver will usually turn the steering wheel to one side by a large angle, so when the turning angle of the steering wheel is greater than a preset angle, stability control is performed.

[0181] The preset angle is pre-calibrated according to real vehicle experiments and / or model calculations, or is pre-set by comprehensively considering the whole vehicle demand and vehicle performance.

[0182] After the steering wheel is turned to one side, the electric vehicle 10 determines whether the electric vehicle 10 performs emergency lane change according to the steering speed of the steering wheel. The driver usually turns the steering wheel to one side quickly when emergency lane change is needed, and thus the stable control is performed when the steering speed of the steering wheel is greater than a preset speed.

[0183] The preset speed is preset according to real vehicle experiments and / or model calculation, or is preset by comprehensively considering the whole vehicle demand and vehicle performance.

[0184] After the steering wheel is turned to one side, the electric vehicle 10 determines whether the electric vehicle 10 performs emergency lane change according to the yaw rate. The direction of the electric vehicle 10 changes rapidly and the yaw rate rises quickly when the electric vehicle 10 performs emergency lane change, and thus the stable control is performed when the yaw rate is greater than a preset angle speed.

[0185] The preset angle speed is preset according to real vehicle experiments and / or model calculation, or is preset by comprehensively considering the whole vehicle demand and vehicle performance.

[0186] In an embodiment, the control method further comprises, after the steering wheel is turned to one side, controlling the positive torque output by the driving system 50 to the rear wheel on one side to change with the opening degree of the accelerator pedal, and controlling the reverse torque output by the driving system 50 to the rear wheel on the other side to change with the opening degree of the accelerator pedal.

[0187] During the emergency lane change, the driving system 50 outputs the positive torque indicated by the opening degree of the accelerator pedal to the steering side wheel, and the size of the positive torque changes with the opening degree of the accelerator pedal.

[0188] The yaw rate of the electric vehicle 10 during the emergency lane change is affected by the vehicle speed of the electric vehicle 10, the faster the vehicle speed, the greater the change of the yaw rate, and thus the electric vehicle 10 needs greater righting torque to stabilize the electric vehicle 10, and if the driver steps on the accelerator pedal, the vehicle speed of the electric vehicle 10 will change, and at this time the size of the reverse torque output to the rear wheel is determined according to the size of the opening degree of the accelerator pedal.

[0189] In an implementation, after the steering wheel is turned to one side, the greater the vehicle speed of the electric vehicle 10, the greater the positive torque output by the driving system 50 to the rear wheel on one side, and the greater the reverse torque output by the driving system 50 to the rear wheel on the other side.

[0190] In an embodiment, the control method further comprises, after the steering wheel is turned to one side, controlling the reverse torque output by the driving system 50 to the rear wheel on the other side to increase with the increase of the steering angle or the steering speed of the steering wheel.

[0191] The yaw rate of the electric vehicle 10 during the emergency lane-changing process is also affected by the steering wheel rotation angle and rotation speed. The greater the steering wheel rotation angle or the faster the steering wheel rotation speed, the greater the change in the yaw rate of the electric vehicle 10, and thus the greater the return torque required by the electric vehicle 10 to stabilize the electric vehicle 10. The greater the steering wheel rotation angle or the faster the steering wheel rotation speed, the greater the reverse torque output by the drive system 50 to the rear wheels, and thus the greater the torque difference generated by the two rear wheels, which can enable the electric vehicle 10 to generate a greater return moment.

[0192] In an embodiment, the control method further comprises, after the steering wheel is rotated to one side, increasing the difference between the sum of the braking forces output by the brake system 60 to the two wheels on the other side and the sum of the braking forces output to the two wheels on one side as the steering wheel rotation angle or rotation speed increases.

[0193] After the steering wheel is rotated to one side, the return demand of the electric vehicle 10 is to the other side, and the control method further comprises, after the steering wheel is rotated to one side, increasing the difference between the sum of the braking forces output by the brake system 60 to the two wheels on the other side and the sum of the braking forces output to the two wheels on one side as the steering wheel rotation angle or rotation speed increases.

[0194] In an embodiment, the control method further comprises, after the steering wheel is rotated to one side, increasing the braking force output by the brake system 60 to the front wheel on the other side as the accelerator pedal opening increases.

[0195] The yaw rate of the electric vehicle 10 during the emergency lane-changing process is affected by the vehicle speed of the electric vehicle 10. The faster the vehicle speed, the greater the change in the yaw rate, and thus the greater the return torque required by the electric vehicle 10 to stabilize the electric vehicle 10. If the driver steps on the accelerator pedal, the vehicle speed of the electric vehicle 10 will change, and at this time, the size of the braking force output by the brake system 60 to the front wheel on the other side is determined according to the size of the accelerator pedal opening.

[0196] In an embodiment, the control method further comprises, during the lane-changing process after the brake failure of the two wheels of the electric vehicle 10, controlling the drive system 50 to output positive torque or reverse torque to the two rear wheels, respectively, and controlling the brake system 60 to output braking force to the wheels on the other side to improve the stability of the electric vehicle 10 during the lane-changing process.

[0197] The brake failure of two wheels in the present application refers to that the wheel end brake device for braking the two wheels in the brake system 60 cannot normally output brake force to the corresponding two wheels. The brake failure reasons include actuator failure, brake motor failure, controller failure, and wheel speed sensor failure, etc. When the brake failure of two wheels occurs, the brake system 60 cannot output brake force to the two wheels, which will cause the brake system 60 to reduce the brake effect and stability control effect on the electric vehicle 10, and affect the safety and stability of the electric vehicle 10 during the emergency lane changing process.

[0198] The brake failure of two wheels includes the brake failure of two coaxial wheels, the brake failure of two wheels on the same side, and the brake failure of two diagonal wheels. The two front wheels or the two rear wheels of the electric vehicle 10 are coaxial wheels, the two left wheels or the two right wheels of the electric vehicle 10 are wheels on the same side, and the front left wheel and the rear right wheel of the electric vehicle 10 are diagonal wheels or the front right wheel and the rear left wheel are diagonal wheels.

[0199] The existing electronic stability control system generates a compensatory righting moment by applying brake force to a single wheel through the brake system 60 during the emergency lane changing process of the electric vehicle 10, thereby effectively inhibiting the body roll, and making the actual driving path track the driver's intended path to the maximum extent. Therefore, when the brake failure of two wheels occurs, the brake system 60 cannot effectively control the vehicle body, which is easy to cause the electric vehicle 10 to lose control during the emergency lane changing process.

[0200] When the two wheels fail, the wheel end brake device for braking the two wheels cannot output effective brake force. At this time, the driving system 50 is controlled to output positive torque or reverse torque to the two rear wheels respectively, and the brake system 60 is controlled to output brake force to the wheels on the other side, so as to realize the function of the original electronic stability control system in stability control through the cooperation of the driving system 50 and the brake system 60.

[0201] According to the scheme of the present application, when the brake failure of two wheels occurs, the driving system 50 is controlled to output positive torque or reverse torque to the two rear wheels respectively, and the brake system 60 is controlled to output brake force to the wheels on the other side, so that the electric vehicle 10 generates a righting moment to perform yaw stability control, and then corrects the yaw of the electric vehicle 10, thereby ensuring the safety of the electric vehicle 10 during the emergency lane changing process. Even if brake failure occurs, the electric vehicle 10 can still be controlled.

[0202] In one embodiment, as Figure 11 and Figure 12As shown, in the lane changing process of the two front wheel brake failure of the electric vehicle 10, the control method specifically comprises: after the steering wheel turns to the left side, first controlling the driving system 50 to output positive torque to the left rear wheel and output reverse torque to the right rear wheel; and then controlling the driving system 50 to output reverse torque to the two front wheels. After the steering wheel turns to the right side, first controlling the driving system 50 to output positive torque to the right rear wheel and output reverse torque to the left rear wheel; and then controlling the driving system 50 to output reverse torque to the two front wheels.

[0203] After the steering wheel turns to the left side, the return demand of the electric vehicle 10 is to the right, first controlling the driving system 50 to output positive torque to the left rear wheel and output reverse torque to the right rear wheel, generating a right return moment to correct the yaw of the electric vehicle 10. Then control the driving system 50 to output reverse torque to the two front wheels, thereby providing additional deceleration, so that the electric vehicle 10 is more easily controlled. After the steering wheel turns to the right side, the return demand of the electric vehicle 10 is to the left, first controlling the driving system 50 to output positive torque to the right rear wheel and output reverse torque to the left rear wheel, generating a left return moment to correct the yaw of the electric vehicle 10. Then control the driving system 50 to output reverse torque to the two front wheels, thereby providing additional deceleration, so that the electric vehicle 10 is more easily controlled.

[0204] Exemplarily, in a complete lane changing process, after the first time t1 when the steering wheel starts to turn to the left, before the second time t2 when the steering wheel starts to turn to the right, the driving system 50 is controlled to output positive torque to the left rear wheel and output reverse torque to the right rear wheel, and the driving system 50 is controlled to output reverse torque to the two front wheels. After the second time t2, before the third time t3 when the steering wheel starts to turn to the left, the driving system 50 is controlled to output reverse torque to the left rear wheel and output positive torque to the right rear wheel, and the driving system 50 is controlled to output reverse torque to the two front wheels. After the third time t3, before the fourth time t4 when the steering wheel turns to the right, the driving system 50 is controlled to output positive torque to the left rear wheel and output reverse torque to the right rear wheel, and the driving system 50 is controlled to output reverse torque to the two front wheels.

[0205] According to the scheme of the present application, when the brakes of the two front wheels fail, in the emergency lane changing process of the electric vehicle 10, the driving system 50 is controlled to output positive torque and reverse torque to the two rear wheels respectively, so that the electric vehicle 10 generates a return moment for yaw stability control, and the driving system 50 is further controlled to output reverse torque to the two front wheels, thereby providing additional deceleration, so that the electric vehicle 10 is more easily controlled, thereby correcting the yaw of the electric vehicle 10, and ensuring the safety of the electric vehicle 10 during emergency lane changing. Even if brake failure occurs, the electric vehicle 10 can still be controlled.

[0206] In one embodiment, the control method further comprises, after the steering wheel turns to the left, increasing the brake force output by the brake system 60 to the right rear wheel as the accelerator pedal opening increases when the accelerator pedal opening is greater than the preset opening. After the steering wheel turns to the left, increasing the brake force output by the brake system 60 to the left rear wheel as the accelerator pedal opening increases when the accelerator pedal opening is greater than the preset opening.

[0207] The maximum braking effect that each wheel of the electric vehicle 10 can achieve is fixed. The wheel can achieve braking by the drive system 50 outputting reverse torque, by the brake system 60 outputting brake force, or by the drive system 50 outputting reverse torque in combination with the brake system 60 outputting brake force. The reverse torque output by the drive system 50 is limited, so when the wheel has not reached the maximum braking effect, the brake force output by the brake system 60 can be superimposed to improve the braking effect.

[0208] The yaw rate of the electric vehicle 10 during the emergency lane change process is affected by the speed of the electric vehicle 10, the faster the speed, the greater the change in the yaw rate, so the electric vehicle 10 needs more return torque to stabilize the electric vehicle 10, and if the driver steps on the accelerator pedal, the speed of the electric vehicle 10 will change, when the accelerator pedal opening is less than the preset opening, sufficient return torque can be achieved by controlling the drive system 50 to output positive torque and reverse torque to the two rear wheels. When the accelerator pedal opening is greater than the preset opening, it is insufficient to achieve sufficient return torque by controlling the drive system 50 to output positive torque and reverse torque to the two rear wheels, at this time the brake system 60 is controlled to output brake force in combination with the reverse torque output by the drive system 50, further increasing the return torque of the electric vehicle 10. When the accelerator pedal opening is greater than the preset opening, the brake system 60 outputs brake force to the right rear wheel, and the brake force increases as the accelerator pedal opening increases.

[0209] It should also be understood that the maximum braking effect that each wheel can achieve is limited, when the reverse torque output by the drive system 50 has made the wheel reach the maximum braking effect, the brake system 60 no longer controls the brake force output to the wheel. Similarly, when the reverse torque output by the drive system 50 and the brake force output by the brake system 60 make the wheel reach the maximum braking effect, the brake system 60 no longer increases the brake force output.

[0210] In one embodiment, the control method specifically comprises, after the steering wheel turns to one side, controlling the drive system 50 to output reverse torque to the two front wheels when the speed of the electric vehicle 10 is greater than the preset speed.

[0211] During an emergency lane change, the higher the speed of electric vehicle 10, the greater the change in yaw rate, and the easier it is to lose control. When the speed of electric vehicle 10 is less than the preset speed, the control drive system 50 outputs positive and negative torques to the two rear wheels respectively. The resulting restoring torque is sufficient to correct the yaw of electric vehicle 10, and there is no need to control the drive system 50 to output negative torque to the two front wheels. When the speed of electric vehicle 10 is greater than the preset speed, the restoring torque generated by the drive system 50 outputting positive and negative torques to the two rear wheels respectively is insufficient to correct the yaw of electric vehicle 10, and electric vehicle 10 may lose control. It is necessary to control the drive system 50 to output negative torque to the two front wheels to further provide deceleration. The speed of electric vehicle 10 decreases, making it easier to control.

[0212] In one embodiment, such as Figure 13 and Figure 14 As shown, during a lane change when the brakes on both rear wheels of the electric vehicle 10 fail, the control method specifically includes, after turning the steering wheel to the left, first controlling the drive system 50 to output positive torque to the left rear wheel and reverse torque to the right rear wheel; then controlling the braking system 60 to output a braking force greater than zero to the right front wheel. After turning the steering wheel to the right, first controlling the drive system 50 to output positive torque to the right rear wheel and reverse torque to the left rear wheel; then controlling the braking system 60 to output a braking force greater than zero to the left front wheel.

[0213] After the steering wheel is turned to the left, the electric vehicle 10's return-to-center demand is to the right. First, the drive system 50 outputs positive torque to the left rear wheel and reverse torque to the right rear wheel, generating a rightward return-to-center torque to correct the yaw of the electric vehicle 10. Then, the braking system 60 outputs a braking force greater than zero to the right front wheel, further increasing the rightward return-to-center torque. After the steering wheel is turned to the right, the electric vehicle 10's return-to-center demand is to the left. First, the drive system 50 outputs positive torque to the right rear wheel and reverse torque to the left rear wheel, generating a leftward return-to-center torque to correct the yaw of the electric vehicle 10. Then, the braking system 60 outputs a braking force greater than zero to the left front wheel, further increasing the leftward return-to-center torque.

[0214] Exemplarily, in a complete lane-changing process, after a first time t1 when the steering wheel starts to turn left, before a second time t2 when the steering wheel starts to turn right, the control system controls the drive system 50 to output positive torque to the left rear wheel and output negative torque to the right rear wheel, and controls the brake system 60 to output brake force greater than zero to the right front wheel. After the second time t2, before a third time t3 when the steering wheel starts to turn back left, the control system controls the drive system 50 to output negative torque to the left rear wheel and output positive torque to the right rear wheel, and controls the brake system 60 to output brake force greater than zero to the left front wheel. After the third time t3, before a fourth time t4 when the steering wheel turns back, the control system controls the drive system 50 to output positive torque to the left rear wheel and output negative torque to the right rear wheel, and controls the brake system 60 to output brake force greater than zero to the right front wheel.

[0215] In an embodiment, as shown in FIG. 6, in a lane-changing process with the right front wheel and the right rear wheel of the electric vehicle 10 being disabled, the control method specifically comprises, after the steering wheel turns left, first controlling the drive system 50 to output positive torque to the left rear wheel and output negative torque to the right rear wheel, and then controlling the drive system 50 to output negative torque to both front wheels. Figure 15 and Figure 16 After the steering wheel turns left, the control system controls the drive system 50 to output positive torque to the left rear wheel and output negative torque to the right rear wheel, to generate a rightward return torque to correct the yaw of the electric vehicle 10. Then the control system controls the drive system 50 to output negative torque to both front wheels, to provide additional deceleration, so that the electric vehicle 10 is more controllable. After the steering wheel turns right, the control system controls the drive system 50 to output positive torque to the right rear wheel and output negative torque to the left rear wheel, to generate a leftward return torque to correct the yaw of the electric vehicle 10. Then the control system controls the brake system 60 to output brake force greater than zero to the left front wheel, to further increase the leftward return torque.

[0216] After the steering wheel turns left, the control system controls the drive system 50 to output positive torque to the left rear wheel and output negative torque to the right rear wheel, to generate a rightward return torque to correct the yaw of the electric vehicle 10. Then the control system controls the drive system 50 to output negative torque to both front wheels, to provide additional deceleration, so that the electric vehicle 10 is more controllable. After the steering wheel turns right, the control system controls the drive system 50 to output positive torque to the right rear wheel and output negative torque to the left rear wheel, to generate a leftward return torque to correct the yaw of the electric vehicle 10. Then the control system controls the brake system 60 to output brake force greater than zero to the left front wheel, to further increase the leftward return torque.

[0217] Exemplarily, in a complete lane-changing process, after a first time t1 when the steering wheel starts to turn left, before a second time t2 when the steering wheel starts to turn right, the control system controls the driving system 50 to output positive torque to the left rear wheel and output negative torque to the right rear wheel, and controls the driving system 50 to output negative torque to both front wheels. After the second time t2, before a third time t3 when the steering wheel starts to turn back left, the control system controls the driving system 50 to output negative torque to the left rear wheel and output positive torque to the right rear wheel, and controls the braking system 60 to output braking force greater than zero to the left front wheel. After the third time t3, before a fourth time t4 when the steering wheel turns back, the control system controls the driving system 50 to output positive torque to the left rear wheel and output negative torque to the right rear wheel, and controls the driving system 50 to output negative torque to both front wheels.

[0218] In an embodiment, as shown in FIG. 4, in a lane-changing process with the left front wheel and the right rear wheel of the electric vehicle 10 braking failure, the control method specifically comprises, after the steering wheel turns left, first controlling the driving system 50 to output positive torque to the left rear wheel and output negative torque to the right rear wheel; and then controlling the braking system 60 to output braking force greater than zero to the right front wheel. After the steering wheel turns right, first controlling the driving system 50 to output positive torque to the right rear wheel and output negative torque to the left rear wheel; and then controlling the driving system 50 to output negative torque to both front wheels. Figure 17 and Figure 18 In an embodiment, as shown in FIG. 4, in a lane-changing process with the left front wheel and the right rear wheel of the electric vehicle 10 braking failure, the control method specifically comprises, after the steering wheel turns left, first controlling the driving system 50 to output positive torque to the left rear wheel and output negative torque to the right rear wheel; and then controlling the braking system 60 to output braking force greater than zero to the right front wheel. After the steering wheel turns right, first controlling the driving system 50 to output positive torque to the right rear wheel and output negative torque to the left rear wheel; and then controlling the driving system 50 to output negative torque to both front wheels.

[0219] After the steering wheel turns left, the turning-back demand of the electric vehicle 10 is to the right, first controlling the driving system 50 to output positive torque to the left rear wheel and output negative torque to the right rear wheel to generate a turning-back moment to the right to correct the yaw of the electric vehicle 10. Then controlling the braking system 60 to output braking force greater than zero to the right front wheel to further increase the turning-back moment to the right. After the steering wheel turns right, the turning-back demand of the electric vehicle 10 is to the left, first controlling the driving system 50 to output positive torque to the right rear wheel and output negative torque to the left rear wheel to generate a turning-back moment to the left to correct the yaw of the electric vehicle 10. Then controlling the driving system 50 to output negative torque to both front wheels to provide additional deceleration so that the electric vehicle 10 is more controllable.

[0220] For example, during a complete lane change, after the first moment t1 when the steering wheel begins to turn left and before the second moment t2 when the steering wheel begins to turn right, the drive system 50 outputs positive torque to the left rear wheel and negative torque to the right rear wheel, while the braking system 60 outputs a braking force greater than zero to the right front wheel. After the second moment t2 and before the third moment t3 when the steering wheel begins to return to center, the drive system 50 outputs negative torque to the left rear wheel and positive torque to the right rear wheel, while also outputting negative torque to both front wheels. After the third moment t3 and before the fourth moment t4 when the steering wheel returns to center, the drive system 50 outputs positive torque to the left rear wheel and negative torque to the right rear wheel, while the braking system 60 outputs a braking force greater than zero to the right front wheel.

[0221] like Figure 20 and Figure 26 As shown, when the electric vehicle 10 makes an emergency lane change, the return-to-center requirement is calculated based on the driving state of the electric vehicle 10, and the electric vehicle 10 is controlled according to the braking capacity of each wheel. When the braking of two wheels fails, the drive system 50 and the braking system 60 are controlled differently according to the direction of return-to-center and the position of the wheel with failed braking. The vehicle status signals include the electric vehicle 10's speed, acceleration, yaw rate, steering wheel signal, wheel speed signal, and load information. The specific control method is described above and will not be repeated here.

[0222] The following is combined Figures 21-25 Another control method for an electric vehicle 10, a motor controller 4050, and an electric vehicle 10 provided in this application embodiment will be described. Figure 22 and Figure 24 This is a signal timing diagram of electric vehicle 10 during its operation. Figure 22 and Figure 24 This includes the relationship between the drive system 50, the braking system 60, and the steering wheel angle during an emergency lane change by the electric vehicle 10. Figure 21 and Figure 23 This is a schematic diagram of an electric vehicle 10 during an emergency lane change. Figure 25 This is a schematic diagram of the control process during an emergency lane change when the brakes on both wheels of an electric vehicle 10 fail.

[0223] This control method is used to control the braking system 60 and the drive system 50 to improve the stability of the electric vehicle 10 during lane changing.

[0224] The control method comprises: before the steering wheel turns to one side, controlling the brake system 60 to output a braking force of zero and controlling the drive system 50 to output positive torques to the four wheels, the positive torques being in the same direction as the wheel speeds. After the steering wheel turns to one side, first controlling the brake system 60 to output a sum of braking forces to the two wheels on one side that is less than a sum of braking forces to the two wheels on the other side; and then controlling the drive system 50 to output a reverse torque to at least one wheel, the reverse torque being in the opposite direction to the rotational speed.

[0225] Before the steering wheel turns to one side, the electric vehicle 10 travels in a straight line, and the driver steps on the accelerator pedal. The electric vehicle 10 controls the brake system 60 to output a braking force of zero and controls the drive system 50 to output positive torques to the four wheels, the positive torques being in the same direction as the wheel speeds, to drive the electric vehicle 10.

[0226] After the steering wheel turns to one side, the electric vehicle 10 changes lanes to one side. Since it is an emergency lane change, the electric vehicle 10 can turn too much. In order to ensure stability, the electric vehicle 10 needs to generate a yaw torque to the other side. At this time, first, the brake system 60 is controlled to output a sum of braking forces to the two wheels on one side that is less than a sum of braking forces to the two wheels on the other side, so that the electric vehicle 10 receives different braking forces on the left and right sides, which causes the electric vehicle 10 to generate a yaw torque to the other side and thus improves the stability of the electric vehicle 10. Further, the drive system 50 is controlled to output a reverse torque to at least one wheel, which is the rear wheel on the other side or the two front wheels, so as to increase the return torque or slow down the electric vehicle 10 and improve the stability of the electric vehicle 10.

[0227] According to the scheme of the present application, during the emergency lane change of the electric vehicle 10, different braking forces are output to the two sides of the electric vehicle 10 by the brake system 60, and a reverse torque is output by the drive system 50, so that the electric vehicle 10 generates a yaw torque for yaw stability control, and thus corrects the yaw of the electric vehicle 10, ensuring the safety of the electric vehicle 10 during the emergency lane change.

[0228] In one embodiment, the control method further comprises: after the steering wheel turns to one side, when it is detected that the turning angle of the steering wheel is greater than a preset angle, or the turning speed is greater than a preset speed, or the yaw angular velocity of the electric vehicle 10 is greater than a preset angular velocity, first controlling the brake system 60 to output a sum of braking forces to the two wheels on one side that is less than a sum of braking forces to the two wheels on the other side; and then controlling the drive system 50 to output a reverse torque to at least one wheel.

[0229] After the steering wheel is turned to one side, the electric vehicle 10 determines whether the electric vehicle 10 performs emergency lane change according to the turning angle of the steering wheel. The driver usually turns the steering wheel to one side greatly when the emergency lane change is needed, and thus the stability control is performed when the turning angle of the steering wheel is greater than a preset angle.

[0230] The preset angle is preset according to real vehicle experiments and / or model calculation, or is preset by comprehensively considering the whole vehicle demand and vehicle performance.

[0231] After the steering wheel is turned to one side, the electric vehicle 10 determines whether the electric vehicle 10 performs emergency lane change according to the turning speed of the steering wheel. The driver usually turns the steering wheel to one side quickly when the emergency lane change is needed, and thus the stability control is performed when the turning speed of the steering wheel is greater than a preset speed.

[0232] The preset speed is preset according to real vehicle experiments and / or model calculation, or is preset by comprehensively considering the whole vehicle demand and vehicle performance.

[0233] After the steering wheel is turned to one side, the electric vehicle 10 determines whether the electric vehicle 10 performs emergency lane change according to the yaw rate. The yaw rate rises quickly when the electric vehicle 10 performs emergency lane change, and thus the stability control is performed when the yaw rate is greater than a preset yaw rate.

[0234] The preset yaw rate is preset according to real vehicle experiments and / or model calculation, or is preset by comprehensively considering the whole vehicle demand and vehicle performance.

[0235] In an embodiment, the control method further comprises increasing the difference between the sum of the brake forces output by the brake system 60 to the two wheels on the other side and the sum of the brake forces output by the brake system 60 to the two wheels on one side as the turning angle or the turning speed of the steering wheel increases after the steering wheel is turned to one side.

[0236] After the steering wheel is turned to one side, the return demand of the electric vehicle 10 is to the other side, and the sum of the brake forces output by the brake system 60 to the two wheels on the other side is greater than the sum of the brake forces output by the brake system 60 to the two wheels on one side, so that the brake forces received by the two sides of the electric vehicle 10 are not equal, a return torque is generated to correct the yaw of the electric vehicle 10. The greater the turning angle of the steering wheel or the faster the turning speed of the steering wheel, the greater the change of the yaw rate of the electric vehicle 10, and thus the electric vehicle 10 needs a greater return torque to stabilize the electric vehicle 10. The greater the turning angle of the steering wheel or the faster the turning speed of the steering wheel, the greater the difference between the brake forces output by the brake system 60 to the two sides of the electric vehicle 10, and thus the electric vehicle 10 can generate a greater yaw torque.

[0237] In an embodiment, the control method further comprises increasing the sum of the braking forces output by the brake system 60 to the two wheels on the other side as the accelerator pedal opening increases after the steering wheel turns to one side.

[0238] The yaw rate of the electric vehicle 10 during the emergency lane change process is affected by the speed of the electric vehicle 10, the faster the speed, the greater the change in the yaw rate, and thus the electric vehicle 10 requires greater return torque to stabilize the electric vehicle 10, and if the driver steps on the accelerator pedal, the speed of the electric vehicle 10 will change, at which point the sum of the braking forces output by the brake system 60 to the two wheels on the other side is determined according to the size of the accelerator pedal opening.

[0239] In an embodiment, the control method further comprises controlling the brake system 60 to output different braking forces to the wheels on both sides and controlling the drive system 50 to output a reverse torque to at least one wheel to improve the stability of the electric vehicle 10 during the lane change process after the three wheels of the electric vehicle 10 fail to brake.

[0240] In this application, the failure of the three wheels to brake means that the wheel end brake device in the brake system 60 for braking the three wheels cannot normally output braking force to the corresponding three wheels. The causes of brake failure include actuator failure, brake motor failure, controller failure, and wheel speed sensor failure. When the three wheels fail to brake, the brake system 60 cannot output braking force to the three wheels, which will result in a decrease in the braking effect and stability control effect of the brake system 60 on the electric vehicle 10, affecting the safety and stability of the electric vehicle 10 during the emergency lane change process.

[0241] The existing electronic stability control system, during the emergency lane change process of the electric vehicle 10, applies braking force to a single wheel through the brake system 60 to generate a compensatory return torque, thereby effectively suppressing the body roll and making the actual driving path track the driver's intended path to the maximum extent. Therefore, when the three wheels fail to brake, the brake system 60 cannot effectively control the body, which can easily lead to loss of control of the electric vehicle 10 during the emergency lane change process.

[0242] When the three wheels fail, only one wheel end brake device of a wheel can output effective braking force, at which point the brake system 60 is controlled to output different braking forces to the wheels on both sides, and the drive system 50 is controlled to output a reverse torque to at least one wheel, thereby achieving the function of the original electronic stability control system in stability control through the drive system 50 in cooperation with the brake system 60.

[0243] According to the scheme of the present application, when the braking of three wheels fails, by controlling the braking forces output by the braking system 60 to the wheels on both sides to be different, and controlling the drive system 50 to output reverse torque to at least one wheel, the electric vehicle 10 generates a yaw torque to perform yaw stability control, thereby correcting the yaw of the electric vehicle 10, ensuring the safety of the electric vehicle 10 when changing lanes in an emergency, and still being able to keep the electric vehicle 10 under control even if the braking fails.

[0244] In an embodiment, as shown in FIG. 1, the control method specifically includes, during the lane changing process of the electric vehicle 10 when the braking of the three wheels other than the right front wheel fails, after the steering wheel turns to the left side, first controlling the braking system 60 to output a braking force greater than zero to the right front wheel, and then controlling the drive system 50 to output a forward torque to the left rear wheel and a reverse torque to the right rear wheel. Figure 21 and 22 In an embodiment, as shown in FIG. 1, the control method specifically includes, during the lane changing process of the electric vehicle 10 when the braking of the three wheels other than the right front wheel fails, after the steering wheel turns to the left side, first controlling the braking system 60 to output a braking force greater than zero to the right front wheel, and then controlling the drive system 50 to output a forward torque to the left rear wheel and a reverse torque to the right rear wheel.

[0245] When only the right front wheel braking is normal, the braking system 60 outputs zero braking force to the other wheels. After the steering wheel turns to the left side, the return demand of the electric vehicle 10 is to the right, first controlling the braking system 60 to output a braking force greater than zero to the right front wheel, so that the braking force on the right side of the electric vehicle 10 is greater than that on the left side, generating a right return torque to correct the yaw of the electric vehicle 10. Further, the drive system 50 is further controlled to output a forward torque to the left rear wheel and a reverse torque to the right rear wheel, generating a left return torque to correct the yaw of the electric vehicle 10.

[0246] In another embodiment, the braking normal side wheel is different from the return side. During the lane changing process of the electric vehicle 10 when the braking of the three wheels other than the right front wheel fails, after the steering wheel turns to the right side, first controlling the drive system 50 to output a forward torque to the right rear wheel and a reverse torque to the left rear wheel, and then controlling the drive system 50 to output a reverse torque to the two front wheels.

[0247] Exemplarily, in a complete lane changing process, after a first time t1 when the steering wheel starts to turn to the left, before a second time t2 when the steering wheel starts to turn to the right, the drive system 50 is controlled to output a forward torque to the left rear wheel and a reverse torque to the right rear wheel, and the braking system 60 is controlled to output a braking force greater than zero to the right front wheel. After the second time t2, before a third time t3 when the steering wheel starts to turn to the left, the drive system 50 is controlled to output a reverse torque to the left rear wheel and a forward torque to the right rear wheel, and the drive system 50 is controlled to output a reverse torque to the two front wheels. After the third time t3, before a fourth time t4 when the steering wheel turns to the right, the drive system 50 is controlled to output a forward torque to the left rear wheel and a reverse torque to the right rear wheel, and the braking system 60 is controlled to output a braking force greater than zero to the right front wheel.

[0248] In another embodiment, in the lane changing process with the failure of the braking of the three wheels of the electric vehicle 10 except the left front wheel, after the steering wheel is turned to the left side, the driving system 50 is first controlled to output a positive torque to the left rear wheel and a reverse torque to the right rear wheel, and then the driving system 50 is controlled to output a reverse torque to the two front wheels.

[0249] In another embodiment, in the lane changing process with the failure of the braking of the three wheels of the electric vehicle 10 except the left front wheel, after the steering wheel is turned to the right side, the driving system 50 is first controlled to output a positive torque to the right rear wheel and a reverse torque to the left rear wheel, and then the driving system 50 is controlled to output a reverse torque to the two front wheels.

[0250] In one embodiment, the control method further comprises, after the steering wheel is turned to the left side, controlling the driving system 50 to output a positive torque to the left rear wheel that varies with the opening degree of the accelerator pedal, and controlling the driving system 50 to output a reverse torque to the right rear wheel that varies with the opening degree of the accelerator pedal.

[0251] In the process of emergency lane changing, the driving system 50 outputs a positive torque to the steering side wheel indicated by the opening degree of the accelerator pedal, and the size of the positive torque varies with the opening degree of the accelerator pedal.

[0252] The yaw angular velocity of the electric vehicle 10 in the process of emergency lane changing is affected by the speed of the electric vehicle 10, the faster the speed, the greater the change of the yaw angular velocity, and therefore the electric vehicle 10 needs a greater return torque to stabilize the electric vehicle 10, and if the driver steps on the accelerator pedal, the speed of the electric vehicle 10 will change, at which time the size of the reverse torque output to the rear wheel is determined according to the size of the opening degree of the accelerator pedal.

[0253] In one implementation, after the steering wheel is turned to the left side, the greater the speed of the electric vehicle 10, the greater the positive torque controlled by the driving system 50 to output to the rear wheel on one side, and the greater the reverse torque controlled by the driving system 50 to output to the rear wheel on the other side.

[0254] In one embodiment, the control method further comprises, after the steering wheel is turned to the left side, controlling the driving system 50 to increase the reverse torque output to the right rear wheel as the turning angle or turning speed of the steering wheel increases.

[0255] The yaw rate of the electric vehicle 10 during the emergency lane-changing process is also affected by the steering wheel rotation angle and rotation speed. The greater the steering wheel rotation angle or the faster the steering wheel rotation speed, the greater the change in the yaw rate of the electric vehicle 10, and thus the greater the return torque required for the electric vehicle 10 to stabilize. The greater the steering wheel rotation angle or the faster the steering wheel rotation speed, the greater the reverse torque output by the drive system 50 to the rear wheels, and thus the greater the torque difference generated by the two rear wheels, which can enable the electric vehicle 10 to generate a greater return moment.

[0256] In one embodiment, as shown in FIG. 1, the control method specifically comprises, during the lane-changing process in which the brakes of the three wheels of the electric vehicle 10 other than the right rear wheel fail, controlling the drive system 50 to output a positive torque to the right rear wheel and a reverse torque to the left rear wheel after the steering wheel is turned to the left side, and then controlling the drive system 50 to output a reverse torque to the two front wheels. Figure 23 and Figure 24 In one embodiment, as shown in FIG. 1, the control method specifically comprises, during the lane-changing process in which the brakes of the three wheels of the electric vehicle 10 other than the right rear wheel fail, controlling the drive system 50 to output a positive torque to the right rear wheel and a reverse torque to the left rear wheel after the steering wheel is turned to the left side, and then controlling the drive system 50 to output a reverse torque to the two front wheels.

[0257] When only the right rear wheel brake is normal, the brake system 60 outputs zero brake force to the other wheels. After the steering wheel is turned to the left side, the return demand of the electric vehicle 10 is to the right, and the brake system 60 is first controlled to output a brake force greater than zero to the right rear wheel, so that the right side of the electric vehicle 10 is subjected to a greater brake force than the left side, generating a right return moment to correct the yaw of the electric vehicle 10. Further, the drive system 50 is then controlled to output a reverse torque to the two front wheels, thereby providing additional deceleration, so that the electric vehicle 10 is more easily controlled.

[0258] In another embodiment, the normal brake side is different from the return side. During the lane-changing process in which the brakes of the three wheels of the electric vehicle 10 other than the left rear wheel fail, the drive system 50 is first controlled to output a positive torque to the right rear wheel and a reverse torque to the left rear wheel after the steering wheel is turned to the right side, and then the drive system 50 is controlled to output a reverse torque to the two front wheels.

[0259] Exemplarily, in a complete lane-changing process, after a first time t1 at which the steering wheel begins to turn to the left, before a second time t2 at which the steering wheel begins to turn to the right, the brake system 60 is controlled to output a brake force greater than zero to the right rear wheel, and the drive system 50 is controlled to output a reverse torque to the two front wheels. After the second time t2, before a third time t3 at which the steering wheel begins to return to the left, the drive system 50 is controlled to output a reverse torque to the left rear wheel and a positive torque to the right rear wheel, and the drive system 50 is controlled to output a reverse torque to the two front wheels. After the third time t3, before a fourth time t4 at which the steering wheel returns, the brake system 60 is controlled to output a brake force greater than zero to the right rear wheel, and the drive system 50 is controlled to output a reverse torque to the two front wheels.

[0260] In another embodiment, in the process of lane changing with three wheels of the electric vehicle 10 losing braking, after the steering wheel is turned to the left, the driving system 50 is first controlled to output positive torque to the left rear wheel and output reverse torque to the right rear wheel, and then the driving system 50 is controlled to output reverse torque to the two front wheels.

[0261] In another embodiment, in the process of lane changing with three wheels of the electric vehicle 10 losing braking, after the steering wheel is turned to the right, the driving system 50 is first controlled to output braking force greater than zero to the left rear wheel, and then the driving system 50 is controlled to output reverse torque to the two front wheels.

[0262] In an embodiment, the control method specifically comprises, after the steering wheel is turned to the left, when the vehicle speed of the electric vehicle 10 is greater than a preset vehicle speed, controlling the driving system 50 to output reverse torque to the two front wheels.

[0263] In the process of emergency lane changing, the greater the vehicle speed of the electric vehicle 10, the greater the change in the yaw rate, and the more likely it is to lose control. When the vehicle speed of the electric vehicle 10 is less than the preset vehicle speed, the driving system 60 is controlled to output braking force greater than zero to the right rear wheel, and the generated righting moment is sufficient to correct the yaw of the electric vehicle 10, so there is no need to control the driving system 50 to output reverse torque to the two front wheels. When the vehicle speed of the electric vehicle 10 is greater than the preset vehicle speed, the righting moment generated by the driving system 60 outputting braking force to the right rear wheel is insufficient to correct the yaw of the electric vehicle 10, and the electric vehicle 10 may lose control, so the driving system 50 needs to be controlled to output reverse torque to the two front wheels, thereby further providing deceleration, reducing the speed of the electric vehicle, and thus making it easier to control.

[0264] In an embodiment, the control method specifically comprises, after the steering wheel is turned to the left, controlling the reverse torque output by the driving system 50 to the two front wheels to change with the opening of the accelerator pedal.

[0265] The yaw rate of the electric vehicle 10 in the process of emergency lane changing is affected by the vehicle speed of the electric vehicle 10, and the faster the vehicle speed, the greater the change in the yaw rate. In the case where the righting moment is constant, greater deceleration is required to stabilize the electric vehicle 10. If the driver steps on the accelerator pedal, the vehicle speed of the electric vehicle 10 will change, and the size of the reverse torque output by the driving system 50 to the two front wheels is determined according to the opening of the accelerator pedal.

[0266] It should also be understood that the maximum braking effect that can be achieved by the driving system 50 outputting reverse torque to the two front wheels is limited, and when the reverse torque output by the driving system 50 has caused the wheels to reach the maximum braking effect, the driving system 60 is no longer controlled to output braking force to the wheels.

[0267] In one embodiment, the control method specifically includes controlling the reverse torque output by the drive system 50 to the two front wheels to increase as the steering wheel rotation angle or rotation speed increases after the steering wheel is turned to the left.

[0268] The yaw rate of electric vehicle 10 during an emergency lane change is also affected by the steering wheel angle and speed. A larger steering wheel angle or a faster steering wheel speed results in a greater change in the yaw rate of electric vehicle 10, requiring a larger deceleration to stabilize the vehicle while maintaining a constant return torque. Conversely, a larger steering wheel angle or a faster steering wheel speed also increases the magnitude of the counter-torque output by the drive system 50 to the two front wheels, resulting in greater deceleration and contributing to the vehicle's stability.

[0269] like Figure 25 and Figure 26 As shown, when the electric vehicle 10 makes an emergency lane change, the return-to-center requirement is calculated based on the driving state of the electric vehicle 10, and the electric vehicle 10 is controlled according to the braking capacity of each wheel. When the braking of three wheels fails, the drive system 50 and the braking system 60 are controlled differently according to the direction of return-to-center and the position of the wheel with failed braking. The vehicle status signals include the electric vehicle 10's speed, acceleration, yaw rate, steering wheel signal, wheel speed signal, and load information. The specific control method is described above and will not be repeated here.

[0270] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A control method for electric vehicles, characterized in that, The control method is used to control the drive system to output positive torque and negative torque to the two rear wheels respectively during the lane change process of the electric vehicle. The direction of the positive torque is the same as the wheel speed direction, and the direction of the negative torque is opposite to the wheel speed direction. The control method includes: After the first moment when the steering wheel begins to turn to the left and before the second moment when the steering wheel begins to turn to the right, the drive system is controlled to output the positive torque to the left rear wheel and the reverse torque to the right rear wheel; After the second moment and before the third moment when the steering wheel begins to return to the left, the drive system is controlled to output the reverse torque to the left rear wheel and the positive torque to the right rear wheel; After the third moment and before the fourth moment when the steering wheel returns to center, the drive system is controlled to output the positive torque to the left rear wheel and the reverse torque to the right rear wheel.

2. The control method according to claim 1, characterized in that, The control method further includes: Before the first moment, during the driving process when the steering wheel is not turned, the drive system is controlled to output the positive torque to the two rear wheels; After the fourth moment, during the driving process when the steering wheel is not turned, the drive system is controlled to output the positive torque to the two rear wheels.

3. The control method according to claim 1 or 2, characterized in that, The control method further includes: Between the first moment and the second moment, and between the third moment and the fourth moment, the drive system is controlled to output positive torque to the left rear wheel in a manner that varies with the opening of the accelerator pedal; Between the second and third time points, the positive torque output by the drive system to the right rear wheel varies with the opening of the accelerator pedal.

4. The control method according to claim 2 or 3, characterized in that, The control method further includes: Between the first moment and the second moment, when it is detected that the steering wheel rotation angle is greater than a preset angle, or the rotation speed is greater than a preset speed, or the yaw rate of the electric vehicle is greater than a preset angular rate, the drive system is controlled to output reverse torque to the right rear wheel.

5. The control method according to any one of claims 1-4, characterized in that, The control method specifically includes: Between the first moment and the second moment, and between the third moment and the fourth moment, the reverse torque output by the drive system to the right rear wheel increases as the opening of the accelerator pedal increases; Between the second and third time points, the reverse torque output by the drive system to the left rear wheel increases as the opening of the accelerator pedal increases.

6. The control method according to any one of claims 1-4, characterized in that, The control method specifically includes: Between the first moment and the second moment, and between the third moment and the fourth moment, the reverse torque output by the drive system to the right rear wheel increases as the rotation angle or rotation speed of the steering wheel increases; Between the second and third moments, the reverse torque output by the drive system to the left rear wheel increases as the rotation angle or rotation speed of the steering wheel increases.

7. The control method according to any one of claims 1-6, characterized in that, The control method further includes: Between the first moment and the second moment, and between the third moment and the fourth moment, the sum of the braking forces output by the braking system of the electric vehicle to the two right wheels is greater than the sum of the braking forces output to the two left wheels. Between the second and third time points, the sum of the braking forces output by the braking system to the two left wheels is greater than the sum of the braking forces output to the two right wheels.

8. The control method according to any one of claims 4-7, characterized in that, The control method specifically includes: Between the first moment and the second moment, and between the third moment and the fourth moment, the sum of the braking forces output by the braking system of the electric vehicle to the two right wheels increases as the accelerator pedal opening increases; Between the second and third time points, the sum of the braking forces output by the braking system to the two left wheels increases as the accelerator pedal opening increases.

9. The control method according to any one of claims 4-7, characterized in that, The control method specifically includes: Between the first moment and the second moment, and between the third moment and the fourth moment, the sum of the braking forces output by the braking system of the electric vehicle to the two right wheels increases as the rotation angle or rotation speed of the steering wheel increases. Between the second and third moments, the sum of the braking forces output by the braking system to the two left wheels increases as the rotation angle or speed of the steering wheel increases.

10. The control method according to any one of claims 1-9, characterized in that, The control method is specifically used for: During lane change after the braking of one wheel of the electric vehicle fails, the drive system is controlled to output a positive torque in the same direction as the wheel speed or a reverse torque in the opposite direction to the wheel speed to the two rear wheels to improve the stability of the electric vehicle during the lane change.

11. The control method according to any one of claims 7-10, characterized in that, During lane-changing when the right rear wheel brake of the electric vehicle fails, the control method specifically includes: Between the first moment and the second moment, and between the third moment and the fourth moment, the braking system is controlled to output zero braking force to the left front wheel, and the braking system is controlled to output greater than zero braking force to the right front wheel; Between the second and third time points, the braking system is controlled to output zero braking force to the right front wheel and to output greater than zero braking force to the left front wheel.

12. The control method according to claim 11, characterized in that, The control method further includes: Between the second and third time points, the braking force output by the braking system to the left rear wheel is greater than zero.

13. The control method according to any one of claims 7-10, characterized in that, During lane-changing when the right front wheel brake of the electric vehicle fails, the control method specifically includes: Between the first and second moments, and between the third and fourth moments, the drive system is controlled to output reverse torque to the right rear wheel, and the braking system is controlled to output zero braking force to the left front wheel; Between the second and third moments, the drive system is controlled to output reverse torque to the left rear wheel, and the braking system is controlled to output braking force to the left front wheel greater than zero.

14. A motor controller, characterized in that, The motor controller is used to control the drive system to output torque to the two rear wheels of the electric vehicle. Specifically, the controller is used for: During the lane change process of the electric vehicle, after the first moment when the steering wheel begins to turn to the left and before the second moment when the steering wheel begins to turn to the right, the drive system is controlled to output the positive torque to the left rear wheel and the reverse torque to the right rear wheel; After the second moment and before the third moment when the steering wheel begins to return to the left, the drive system is controlled to output the reverse torque to the left rear wheel and the positive torque to the right rear wheel; After the third moment and before the fourth moment when the steering wheel returns to center, the drive system is controlled to output the positive torque to the left rear wheel and the reverse torque to the right rear wheel.

15. An electric vehicle, characterized in that, The electric vehicle includes a motor controller as described in claim 14, a power battery, a drive system, a braking system, and four wheels. The controller is used to receive power from the power battery and control the drive system to output torque to the two rear wheels.

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