A control method, controller, and electric vehicle for suppressing deviation of the electric vehicle

Abstract

The application discloses a control method, a controller and an electric vehicle for inhibiting deviation of the electric vehicle, and relates to the technical field of new energy vehicles. The control method is used for inhibiting deviation of the electric vehicle after deviation in a straight driving process of the electric vehicle. The control method comprises the following steps: at a first time, a driving system is controlled to output driving torques to left wheels and right wheels of the electric vehicle; at a second time after the first time, a difference between the driving torque of the left wheels and the driving torque of the right wheels is increased; and the steering wheel angle of the electric vehicle is smaller than a steering angle threshold value at the first time and the second time. Thus, the deviation of the electric vehicle in the straight driving process can be inhibited, and the driving safety of the electric vehicle is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy vehicles, and in particular to a control method for suppressing deviation of an electric vehicle, a controller, and an electric vehicle. BACKGROUND

[0002] During straight driving of the electric vehicle, if the speed of the electric vehicle is high and the driver does not turn the steering wheel, the driving direction and trajectory of the electric vehicle will deviate unexpectedly, and the electric vehicle will deviate. This is caused by the fact that the output torques of the left motor and the right motor of the distributed drive electric vehicle have accuracy differences, or the left tire and the right tire have inconsistent wear, thereby reducing the stability and safety of driving the electric vehicle.

[0003] At present, in order to correct the deviation of the electric vehicle during straight driving, the steering system of the electric vehicle is usually controlled. However, during the control process, the neutral value of the steer-by-wire device in the steering system needs to be calibrated. If the calibration is inaccurate or the accuracy of the calibration is poor, it will directly affect the correction effect of the deviation of the electric vehicle.

[0004] Therefore, how to effectively suppress the deviation of the electric vehicle during straight driving and improve the driving safety of the electric vehicle has become a problem to be solved. SUMMARY

[0005] The present application provides a control method for suppressing deviation of an electric vehicle, a controller, and an electric vehicle, which is used to suppress deviation of the electric vehicle during straight driving and improve the driving safety of the electric vehicle.

[0006] To achieve the above-mentioned purpose, the embodiments of the present application adopt the following technical solutions:

[0007] In a first aspect, a control method for suppressing deviation of an electric vehicle is provided. The control method is used to control the electric vehicle to suppress deviation after the electric vehicle deviates during straight driving. The control method comprises: at a first time, controlling a drive system to output a driving torque to a left wheel and a right wheel of the electric vehicle; at a second time after the first time, increasing a difference between the driving torque of the left wheel and the driving torque of the right wheel; wherein the steering wheel angle of the electric vehicle at the first time and the second time is less than a steering angle threshold, indicating that the user does not turn the steering wheel or the angle of the steering wheel turned by the user is small, and the electric vehicle is in a straight driving state.

[0008] In the technical solution, at the first moment, the electric vehicle is still deviating, and the difference between the driving torques of the left wheel and the right wheel is small. At the second moment after the first moment, without the user rotating the steering wheel to control the electric vehicle to adjust the driving direction, the control method provided by the embodiment of the application can actively increase the difference between the driving torques of the left wheel and the right wheel. When the difference between the driving torques of the left wheel and the right wheel is large, the driving forces received by the left wheel and the right wheel are different, and thus the electric vehicle deviates as expected during continuous driving, which can offset the deviation of the electric vehicle, and finally the purpose of suppressing the deviation of the electric vehicle is achieved, and the driving safety of the electric vehicle is improved.

[0009] In any possible implementation manner of the first aspect, at the second moment, the vehicle speed of the electric vehicle is greater than a preset vehicle speed, the lateral deviation of the electric vehicle is greater than a first preset lateral deviation, or the heading angle deviation of the electric vehicle is greater than a preset heading angle deviation. The preset vehicle speed, the first preset lateral deviation, and the preset heading angle deviation are trigger thresholds of the function of suppressing the deviation of the electric vehicle. When the vehicle speed of the electric vehicle is greater than the preset vehicle speed, it indicates that the electric vehicle is currently in a high-speed driving state. When the lateral deviation is greater than the first preset lateral deviation or the heading angle deviation is greater than the preset heading angle deviation, it indicates that the electric vehicle has deviated and the deviation is large during high-speed driving, and the deviation of the electric vehicle needs to be suppressed. In this way, by setting the preset vehicle speed, the first preset lateral deviation, and the preset heading angle deviation, whether the electric vehicle deviates and needs to be suppressed can be detected in time, and the driving safety of the electric vehicle is improved.

[0010] In any possible implementation manner of the first aspect, the control method specifically comprises: at the second moment, when the lateral deviation of the electric vehicle to the left is greater than the first preset lateral deviation, the driving torque of the left wheel is greater than that of the right wheel; and at the second moment, when the lateral deviation of the electric vehicle to the right is greater than the first preset lateral deviation, the driving torque of the right wheel is greater than that of the left wheel. According to the deviation direction of the electric vehicle, the size relationship between the driving torques of the two wheels is adaptively adjusted, the electric vehicle is controlled to deviate in the opposite direction of the deviation, and thus the deviation of the electric vehicle can be effectively suppressed, and the driving safety of the electric vehicle is improved.

[0011] In any possible implementation manner of the first aspect, the control method specifically comprises: at the second time, when the lateral offset of the electric vehicle to the left is greater than the first preset lateral offset, the driving torque of the left wheel is adjusted to increase and the driving torque of the right wheel is adjusted to decrease; at the second time, when the lateral offset of the electric vehicle to the right is greater than the first preset lateral offset, the driving torque of the right wheel is adjusted to increase and the driving torque of the left wheel is adjusted to decrease. The above possible implementation manner adaptively adjusts the size relationship of the driving torques of the wheels on both sides according to the offset direction of the electric vehicle, controls the electric vehicle to offset in the opposite direction of the running offset, thereby effectively inhibiting the running offset of the electric vehicle, and improving the driving safety of the electric vehicle.

[0012] In any possible implementation manner of the first aspect, the control method specifically comprises: at the second time, when the lateral offset of the electric vehicle to the left is greater than the first preset lateral offset, the increase value of the driving torque of the left wheel is equal to the decrease value of the driving torque of the right wheel; at the second time, when the lateral offset of the electric vehicle to the right is greater than the first preset lateral offset, the increase value of the driving torque of the right wheel is equal to the decrease value of the driving torque of the left wheel. The above possible implementation manner adaptively adjusts the size relationship of the driving torques of the wheels on both sides according to the offset direction of the electric vehicle, controls the electric vehicle to offset in the opposite direction of the running offset, thereby effectively inhibiting the running offset of the electric vehicle, and improving the driving safety of the electric vehicle.

[0013] In any possible implementation manner of the first aspect, the control method specifically comprises: at the second time, when the lateral offset of the electric vehicle to the left is greater than the first preset lateral offset and the height of the left wheel is greater than the height of the right wheel, the increase value of the driving torque of the left wheel is less than the decrease value of the driving torque of the right wheel; at the second time, when the lateral offset of the electric vehicle to the left is greater than the first preset lateral offset and the height of the left wheel is less than the height of the right wheel, the increase value of the driving torque of the left wheel is greater than the decrease value of the driving torque of the right wheel. The above possible implementation manner adaptively adjusts the size relationship of the driving torques of the wheels on both sides in combination with the offset direction of the electric vehicle on a complex road surface (for example, a side slope road surface), can control the electric vehicle to offset in the opposite direction of the running offset, thereby effectively inhibiting the running offset of the electric vehicle, and improving the driving safety of the electric vehicle.

[0014] In any possible implementation manner of the first aspect, the control method specifically comprises: at the second time, when the lateral offset of the electric vehicle to the left is greater than the first preset lateral offset and the adhesion coefficient of the left wheel to the road surface is greater than the adhesion coefficient of the right wheel to the road surface, the increase value of the driving torque of the left wheel is greater than the decrease value of the driving torque of the right wheel; at the second time, when the lateral offset of the electric vehicle to the left is greater than the first preset lateral offset and the adhesion coefficient of the left wheel to the road surface is less than the adhesion coefficient of the right wheel to the road surface, the increase value of the driving torque of the left wheel is less than the decrease value of the driving torque of the right wheel. The above possible implementation manner, in combination with the offset direction of the electric vehicle, adaptively adjusts the size relationship of the driving torques of the wheels on both sides on the road surface with complex road conditions (for example, on a split road), can control the electric vehicle to offset in the opposite direction of the expected offset, thereby effectively inhibiting the electric vehicle from offsetting and improving the driving safety of the electric vehicle.

[0015] In any possible implementation manner of the first aspect, the control method specifically comprises: when the lateral offset of the electric vehicle at the second time is a first lateral offset greater than the first preset lateral offset, the difference between the driving torque of the left wheel and the driving torque of the right wheel is increased to a first difference value after the second time; when the lateral offset of the electric vehicle at the second time is a second lateral offset greater than the first lateral offset, the difference between the driving torque of the left wheel and the driving torque of the right wheel is increased to a second difference value after the second time, and the second difference value is greater than the first difference value. The above possible implementation manner adjusts the driving torque of the left wheel and the driving torque of the right wheel of the electric vehicle according to the actual offset situation and degree of the electric vehicle, so that the difference between the driving torque of the left wheel and the driving torque of the right wheel of the electric vehicle increases with the increase of the lateral offset, thereby shortening the control process of inhibiting the electric vehicle from offsetting as much as possible, improving the control efficiency of inhibiting the electric vehicle from offsetting, and improving the driving experience of the electric vehicle.

[0016] In any possible implementation manner of the first aspect, the control method further comprises: at a third time after the second time, adjusting the difference between the driving torque of the left wheel and the driving torque of the right wheel to decrease. The above possible implementation manner, at the third time, the control method provided by the embodiments of the present application can detect that the lateral offset and the heading angle offset of the electric vehicle decrease to the normal range, and actively adjust the difference between the driving torque of the left wheel and the driving torque of the right wheel of the electric vehicle to gradually decrease, so as to make the driving torque of the left wheel and the driving torque of the right wheel return to a balanced state, timely respond to the driving demand of the user operation in the subsequent driving of the electric vehicle, and improve the driving experience of the electric vehicle.

[0017] In any possible implementation manner of the first aspect, at the third time, the steering wheel angle of the electric vehicle is greater than the steering wheel angle threshold or the opening degree of the brake pedal of the electric vehicle is greater than the preset brake pedal opening degree. The possible implementation manner that the steering wheel angle is greater than the steering wheel angle threshold indicates that the user operates the steering wheel and wants to control the electric vehicle to turn or end the straight driving state. The opening degree of the brake pedal is greater than the preset brake pedal opening degree, which indicates that the user steps on the brake pedal and wants to control the speed of the electric vehicle to reduce or stop. At the third time, the electric vehicle can also respond to the user's operation in time, improving the driving experience of the electric vehicle.

[0018] In any possible implementation manner of the first aspect, the control method specifically comprises: at the second time, increasing the difference between the driving torque of the left wheel and the driving torque of the right wheel at a first rate; and at the third time, decreasing the difference between the driving torque of the left wheel and the driving torque of the right wheel at a second rate smaller than the first rate. In the possible implementation manner, at the second time, the difference between the driving torque of the left wheel and the driving torque of the right wheel is actively increased at the first rate; at the third time, the difference between the driving torque of the left wheel and the driving torque of the right wheel is actively decreased at the second rate smaller than the first rate, and the second rate is smaller than the first rate, so that the driving torque of the left wheel and the driving torque of the right wheel can return to the balanced state at a relatively gentle rate, avoiding the jerk caused by the rapid increase or decrease of the driving torque, and improving the driving experience of the user.

[0019] In any possible implementation manner of the first aspect, the control method specifically comprises: during the driving process of the electric vehicle at a first vehicle speed, decreasing the difference between the driving torque of the left wheel and the driving torque of the right wheel at a time when the steering wheel angle of the electric vehicle is greater than a first steering wheel angle threshold, wherein the time when the steering wheel angle is greater than the first steering wheel angle threshold is the third time; and during the driving process of the electric vehicle at a second vehicle speed, decreasing the difference between the driving torque of the left wheel and the driving torque of the right wheel at a time when the steering wheel angle of the electric vehicle is greater than a second steering wheel angle threshold, wherein the time when the steering wheel angle is greater than the second steering wheel angle threshold is the third time; the first vehicle speed is smaller than the second vehicle speed, and the first steering wheel angle threshold is greater than the second steering wheel angle threshold. The control method provided in the embodiments of the present application can configure different steering wheel angle thresholds according to different vehicle speeds, so as to respond to the operation demand of the user in time according to different steering wheel angle thresholds, and improve the driving experience of the user.

[0020] In any possible implementation manner of the first aspect, the control method further includes: outputting an alarm signal to the user when the lateral offset of the electric vehicle is greater than the second preset lateral offset at the second time. The possible implementation manner above indicates that, when the lateral offset of the electric vehicle exceeds the second preset lateral offset at the second time, it means that the lateral offset of the electric vehicle fails to decrease as expected or the lateral offset of the electric vehicle is still increasing in the process of suppressing the deviation of the electric vehicle. Therefore, the alarm signal needs to be output to the user in a timely manner to remind the user to pay attention to the deviation of the electric vehicle, thereby improving the driving safety of the electric vehicle.

[0021] In a second aspect, a controller for an electric vehicle is provided, and the controller is configured to execute the control method for suppressing the deviation of the electric vehicle according to the first aspect or any possible implementation manner of the first aspect.

[0022] In a third aspect, an electric vehicle is provided, and the electric vehicle includes two left wheels, two right wheels and a distributed power assembly. The distributed power assembly includes two drive motors and a controller. The controller is configured to control one drive motor to drive one left wheel and to control another drive motor to drive one right wheel coaxial with the one left wheel. The controller is configured to control the electric vehicle to suppress the deviation of the electric vehicle after the deviation of the electric vehicle occurs during straight driving of the electric vehicle. Specifically, the controller is configured to increase a difference between the torques output by the two drive motors in response to the lateral offset of the electric vehicle being greater than a first preset lateral offset during driving of the electric vehicle at a vehicle speed greater than a preset vehicle speed.

[0023] It can be understood that the controller for the electric vehicle and the electric vehicle provided above can achieve the beneficial effects corresponding to the beneficial effects of the control method for suppressing the deviation of the electric vehicle provided above, which will not be described herein again. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 FIG. 1 is a structural schematic diagram of a steering system;

[0025] Figure 2 FIG. 2 is a structural schematic diagram of an electric vehicle provided in an embodiment of the present application;

[0026] Figure 3 FIG. 3 is a structural schematic diagram of a four-motor distributed drive vehicle provided in an embodiment of the present application;

[0027] Figure 4 FIG. 4 is a structural schematic diagram of a three-motor distributed drive vehicle provided in an embodiment of the present application;

[0028] Figure 5 FIG. 5 is a schematic diagram of deviation of an electric vehicle to the left provided in an embodiment of the present application;

[0029] Figure 6 A schematic diagram of a control process for suppressing deviation of an electric vehicle according to an embodiment of the present application is provided;

[0030] Figure 7 A schematic diagram of another control process for suppressing deviation of an electric vehicle according to an embodiment of the present application is provided;

[0031] Figure 8 A schematic diagram of a control process for suppressing deviation of an electric vehicle based on different heights of wheels according to an embodiment of the present application is provided;

[0032] Figure 9 A schematic diagram of a control process for suppressing deviation of an electric vehicle based on different adhesion coefficients according to an embodiment of the present application is provided;

[0033] Figure 10 A signal timing diagram of a control method for suppressing deviation of an electric vehicle according to an embodiment of the present application is provided;

[0034] Figure 11 A schematic diagram of another control process for suppressing deviation of an electric vehicle according to an embodiment of the present application is provided. DETAILED DESCRIPTION

[0035] The making and using of various embodiments will now be described in detail. It should be appreciated that numerous specific implementation details, relationships, and methods are set forth in order to provide a full and enabling disclosure. Those skilled in the art will readily recognize numerous adaptations of the application as applied to various implementations.

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

[0037] Deviation of an electric vehicle refers to that, in the process of straight driving of an electric vehicle, when the speed of the electric vehicle is high and the user does not turn the steering wheel, the driving direction and trajectory of the electric vehicle will deviate unexpectedly. For example, when a user drives an electric vehicle on a highway, in the case of good road conditions, the user will only exert slight control on the steering wheel and will not hold and turn the steering wheel at all times, and the phenomenon of deviation of the electric vehicle may occur. This is due to the fact that there are differences in output torque between the left motor and the right motor of the distributed drive electric vehicle, or the left tire and the right tire are not worn uniformly, or there are positioning differences between the four wheels of the electric vehicle, etc., which will reduce the driving safety of the electric vehicle.

[0038] In the related art, in order to avoid the deviation phenomenon of the electric vehicle in the process of straight driving, the steering system of the electric vehicle is usually used for control. For example, Figure 1As shown, the steering system mainly includes a steer-by-wire system, an inertial measurement unit (IMU), a computing unit, and a positioning device. The IMU measures the yaw angle deviation between the starting and target markings of the electric vehicle. The positioning device determines the electric vehicle's position coordinates. The computing unit calculates the lateral offset of the electric vehicle based on the yaw angle deviation indicated by the yaw angle information and the electric vehicle's position coordinates. When the lateral offset exceeds a lateral offset threshold, it determines the centering correction value of the steer-by-wire system based on the yaw angle deviation to perform centering calibration, thereby correcting the electric vehicle's deviation from its straight-line trajectory. The steer-by-wire system receives steering commands from the computing unit and controls the steering actions of the electric vehicle.

[0039] In the process of controlling an electric vehicle to go straight and avoid veering using the steering system, it is necessary to calibrate the center correction value of the steer-by-wire system. The accuracy of this calibration has a significant impact on the control effect of correcting the vehicle's veering. When the calibration result is inaccurate or the accuracy of the calibrated center correction value is poor, the control effect of correcting the vehicle's veering will also be poor.

[0040] Therefore, embodiments of this application provide a control method, controller, and electric vehicle for suppressing vehicle deviation. This control method is used to control the electric vehicle to suppress deviation after it deviates while traveling straight. It adjusts the difference between the drive torque of the left wheel and the drive torque of the right wheel by controlling the drive system, thereby effectively correcting the deviation phenomenon during straight-line travel and improving the driving safety of the electric vehicle.

[0041] The electric vehicle provided in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0042] See Figure 2 , Figure 2 This is a structural schematic diagram of an electric vehicle provided as an embodiment of this application. Figure 2 As shown, the electric vehicle 01 includes a vehicle controller 10, a drive system 20, and a power battery 30. The drive system 20, also referred to as a powertrain, includes a motor controller 21 and a drive motor 22. The power battery 30 provides electrical energy to the drive system 20. The vehicle controller 10 outputs a torque signal to the motor controller 21. The motor controller 21 controls the output torque of the drive motor 22 based on this torque signal. Under the control of the motor controller 21, the drive motor 22 provides driving force to the wheels of the electric vehicle 01 to rotate the wheels, thereby driving the electric vehicle 01. Optionally, the electric vehicle 01 also includes a braking system (…). Figure 2 (Not shown in the image), the braking system is used to provide braking force to the wheels of the electric vehicle 01.

[0043] The functions of the vehicle controller 10 will be described in connection with the operating states of the electric vehicle 01. The operating states of the electric vehicle 01 include a driving state and a braking state.

[0044] When the electric vehicle 01 is in the driving state, the drive system 20 drives the wheels to rotate. The vehicle controller 10 calculates the torque demand of the electric vehicle 01 according to the opening degree of the accelerator pedal indicated by the accelerator pedal signal, and outputs a torque signal to the motor controller 21. The motor controller 21 receives electric energy from the power battery 30 and controls the drive motor 22 to output a torque value indicated by the torque signal, i.e., the drive motor 22 provides driving force for the electric vehicle 01.

[0045] When the electric vehicle 01 is in the braking state, the drive system 20 stops driving the wheels to rotate, and the brake system provides braking force for the wheels to reduce the speed of the electric vehicle 01. In the braking state of the electric vehicle 01, the drive motor 22 in the electric vehicle with energy recovery function can also be used to provide braking force for the electric vehicle 01. Specifically, when the electric vehicle 01 is in the braking state, the vehicle controller 10 receives a braking signal and sends an energy recovery instruction to the motor controller 21. The motor controller 21 controls the drive motor 22 to operate in a power generation state in response to the energy recovery instruction. The drive motor 22 converts the kinetic energy of the wheels of the electric vehicle 01 into electric energy and outputs a negative torque to the wheels of the electric vehicle 01 to provide braking force for the electric vehicle 01. Wherein, the drive motor 22 outputs a positive torque means that the output direction of the drive motor 22 is the same as the rotation direction of the drive motor 22; the drive motor 22 outputs a negative torque means that the output direction of the drive motor 22 is opposite to the rotation direction of the drive motor 22.

[0046] In one embodiment, as Figure 2As shown, the electric vehicle 01 also includes a domain controller unit (DCU) 23. Compared with the vehicle controller 10, the domain controller unit 23 has a highly integrated feature, which can integrate the functions of multiple electronic control units (ECUs) into one controller to improve the integration of the control system and reduce the complexity of the control system. The DCU can be used to integrate multiple related functions, such as power domain, chassis domain, body domain, cabin domain, and autonomous driving domain, etc., which are responsible for different functions and control systems of the vehicle. The controller for the electric vehicle provided in the embodiments of the present application can be a power domain controller integrated with the function of suppressing the deviation of the electric vehicle, or an autonomous driving domain controller integrated with the function of suppressing the deviation of the electric vehicle, which is not specifically limited in the embodiments of the present application. In one possible implementation, the domain controller unit 23 can be an independently integrated DCU chip connected with the motor controller 21 in the drive system 20; or as shown in Figure 2 The domain controller unit 23 can also be integrated inside the drive system 20 and connected with the motor controller 21.

[0047] In one embodiment, according to the number of motor controllers 21 and drive motors 22 in the drive system 20, the electric vehicle 01 provided in the embodiments of the present application can be a four-motor distributed drive vehicle (as shown in Figure 3 or a three-motor distributed drive vehicle (as shown in Figure 4 ).

[0048] In one example, as shown in Figure 3 The electric vehicle 01 includes four motor controllers and four drive motors. The four motor controllers include a motor controller 211, a motor controller 212, a motor controller 213, and a motor controller 214. The four drive motors include a drive motor 221, a drive motor 222, a drive motor 223, and a drive motor 224. The motor controller 211 is used to control the drive motor 221 to drive the front left wheel 41, the motor controller 212 is used to control the drive motor 222 to drive the front right wheel 42, the motor controller 213 is used to control the drive motor 223 to drive the rear left wheel 43, and the motor controller 214 is used to control the drive motor 224 to drive the rear right wheel 44.

[0049] In another example, as shown in Figure 4As shown, the electric vehicle 01 includes three motor controllers and drive motors. The three motor controllers are motor controller 211, motor controller 212, and motor controller 213. The three drive motors are drive motor 221, drive motor 222, and drive motor 223. Motor controller 211 controls drive motor 221 to simultaneously drive wheel (left front wheel) 41 and wheel (right front wheel) 42, motor controller 212 controls drive motor 222 to drive wheel (left rear wheel) 43, and motor controller 213 controls drive motor 223 to drive wheel (right rear wheel) 44.

[0050] The architecture of the embodiments of this application has been described above. The technical solutions provided by the embodiments of this application will be described in detail below with reference to specific embodiments.

[0051] The control method provided in this application embodiment is used to control the electric vehicle 01 to suppress deviation after it veers while traveling straight. The relevant steps of this control method can be controlled and executed by the aforementioned controller. The control method includes: at a first moment, controlling the drive system to output drive torque to the left and right wheels of the electric vehicle 01; at a second moment after the first moment, adjusting the difference between the drive torque of the left wheel and the drive torque of the right wheel to increase; wherein, at both the first and second moments, the steering wheel angle of the electric vehicle 01 is less than a steering angle threshold.

[0052] The steering wheel angle can be used to determine whether the electric vehicle 01 is currently in a straight-line state without steering wheel control. When the steering wheel angle is less than a threshold angle, it indicates that the electric vehicle 01 is currently in a straight-line state; when the steering wheel angle is greater than or equal to the threshold angle, it indicates that the user is currently turning the steering wheel and the electric vehicle 01 is not currently in a straight-line state. The control method provided in this application embodiment is used to actively correct the deviation of the electric vehicle when the user does not turn the steering wheel, so as to suppress the deviation of the electric vehicle.

[0053] To facilitate understanding, the following will be combined with Figure 5 The control method provided in the embodiments of this application will be illustrated by example.

[0054] In one embodiment, such as Figure 5 As shown, the example given is an electric vehicle 01 with its left rear wheel 43, its right rear wheel 44, and the vehicle veering to the left. For ease of description, the drive motor for driving the left rear wheel of the electric vehicle 01 will be referred to as the left rear wheel drive motor, and the drive motor for driving the right rear wheel of the electric vehicle 01 will be referred to as the right rear wheel drive motor.

[0055] At the first moment, such as Figure 5As shown, the controller controls the drive system to output drive torque to the left and right wheels of the electric vehicle 01. That is, it controls the left rear wheel drive motor to output drive torque M to the left rear wheel 43 of the electric vehicle 01. l Control the right rear wheel drive motor to output drive torque M to the right rear wheel 44 of electric vehicle 01. r At this time, the drive torque M output by the left rear wheel drive motor is... l With the drive torque M output by the right rear wheel drive motor r The difference between them is small.

[0056] In the second moment after the first moment, such as Figure 5 As shown, the controller controls the drive torque M output by the left rear wheel drive motor. l With the drive torque M output by the right rear wheel drive motor r The difference between them increases. For example, taking the leftward drift of electric vehicle 01 as an example, the controller controls the drive torque M output by the left rear wheel drive motor. l Increase ΔM l_mot The controller also controls the drive torque M output by the right rear wheel drive motor. r Decrease ΔM r_mot At this time, M l With M r The difference between them increased ΔM r_mot +ΔM l_mot In this way, when the torque difference between the left and right rear wheel drive motors is large, the driving force received by the left rear wheel 43 and the right rear wheel 44 will differ significantly (the driving force of the left rear wheel is larger, and the driving force of the right rear wheel is smaller). As the electric vehicle 01 continues to move, the expected deviation will occur due to the inconsistent driving force of the two rear wheels. This expected deviation can cancel out the deviation of the electric vehicle 01, ultimately achieving the goal of suppressing the deviation of the electric vehicle 01 and improving the driving safety of the electric vehicle 01.

[0057] In one embodiment, at a second moment, the electric vehicle's speed is greater than a preset speed, the electric vehicle's lateral offset is greater than a first preset lateral offset, or the electric vehicle's heading angle offset is greater than a preset heading angle offset.

[0058] The vehicle speed indicates the current driving status of electric vehicle 01, used to determine whether electric vehicle 01 is currently in a high-speed driving state. The heading angle offset refers to the angular difference between the heading angle and the desired heading angle when the electric vehicle is traveling straight. The lateral offset refers to the lateral distance by which the electric vehicle deviates to the left or right when traveling straight.

[0059] The preset vehicle speed, the first preset lateral offset, and the preset heading angle offset are trigger thresholds of the deviation suppression function of the electric vehicle. When the vehicle speed of the electric vehicle 01 is greater than the preset vehicle speed, it indicates that the electric vehicle 01 is currently in a high-speed driving state. When the lateral offset is greater than the first preset lateral offset or the heading angle offset is greater than the preset heading angle offset, it indicates that the electric vehicle 01 has deviated during high-speed straight driving and the offset is large, and the deviation of the electric vehicle 01 needs to be suppressed. The controller can actively adjust the difference between the driving torque of the left wheel and the driving torque of the right wheel to increase, so as to suppress the deviation of the electric vehicle 01.

[0060] In an embodiment, the lateral offset and the heading angle offset can be calculated by the vehicle speed and the yaw rate of the electric vehicle. The yaw rate is the angular velocity of the electric vehicle rotating perpendicular to the motion plane. The yaw rate can be detected by the yaw rate sensor of the electric vehicle. The vehicle speed can be detected by the vehicle speed sensor of the electric vehicle. In a possible implementation, the controller can determine the lateral offset and the heading angle offset of the electric vehicle during straight driving according to the obtained yaw rate and vehicle speed, so as to determine the yaw control moment required for suppressing the deviation of the electric vehicle according to the lateral offset and the heading angle offset, and distribute the yaw control moment to the driving motor of the left wheel and the driving motor of the right wheel to suppress the deviation of the electric vehicle.

[0061] The following still takes the offset direction shown in Figure 5 as an example, and Figure 6 and Figure 7 are combined to detail the control process of calculating the heading angle offset θ and the lateral offset l and suppressing the deviation of the electric vehicle 01.

[0062] In an embodiment, as shown in Figure 6 , during the straight driving process of the electric vehicle 01 (the user does not turn the steering wheel, i.e., the steering wheel angle is less than the angle threshold), the yaw rate sensor signal can be used to obtain the yaw rate γ of the electric vehicle 01, and the vehicle speed sensor of the electric vehicle 01 can be used to obtain the vehicle speed v of the electric vehicle 01. The yaw rate sensor and the vehicle speed sensor can output the obtained yaw rate and vehicle speed to the controller (for example, the domain controller DCU), so that the controller calculates the heading angle offset θ and the lateral offset l of the electric vehicle 01 based on the yaw rate γ and the vehicle speed v. The two offsets can be obtained by the following formulas (1) and (2).

[0063]

[0064] Equation (1) represents the integral operation of the yaw rate γ of electric vehicle 01 over a period of time, and the result of this integral operation is the heading angle offset θ. Equation (2) represents the multiplication operation of the vehicle speed v of electric vehicle 01 and the tangent of the heading angle offset θ, and the product is the lateral offset l.

[0065] In one embodiment, such as Figure 6 As shown, after calculating the lateral offset l and heading angle offset θ of the electric vehicle 01, the controller can determine the yaw control torque M based on the lateral offset l and heading angle offset θ. Zt And based on this yaw control torque M Zt The difference between the driving torque of the left wheel and the driving torque of the right wheel is increased by actively adjusting the torque.

[0066] Among them, as mentioned above, the yaw control torque M Zt It is the total control torque used to correct the heading angle deviation θ and the lateral deviation l. (M) Zθ This represents the control torque that corrects the heading angle deviation θ, expressed in M. Zl M represents the control torque that corrects the lateral offset l. Zt =M Zθ +M Zl .

[0067] In one possible implementation, the control torque M Zθ and control torque M Zl This can be calculated using a proportional-integral-differential (PID) closed-loop controller. The PID closed-loop controller can be deployed within the controller. After determining the heading angle offset θ and lateral offset l, the controller can input these offsets as error quantities into the PID closed-loop controller to obtain the control torque M required to correct each offset. Zθ and M Zl Control torque M Zθ and M Zl By adding them together, the yaw control torque M can be determined. Zt .

[0068] In one embodiment, such as Figure 7 As shown, the controller obtains the yaw control torque M Zt Then, the yaw control torque M can be adjusted. Zt This is converted into tire force increment ΔF, and further converted into the change in drive torque of the left wheel and the right wheel ΔM. mot The increase in tire force ΔF and the change in driving torque ΔM motIt can be obtained by the following formulas (3) and (4) respectively. Among them, the tire force represents the frictional force between the left wheel and the right wheel and the ground under the action of the driving torque. In this embodiment, the left wheel is still the left rear wheel 43 and the right wheel is the right rear wheel 44 as an example for explanation.

[0069]

[0070] In equation (3), ΔF l This indicates the increase in tire force for the left rear wheel (43). This represents the yaw torque distribution factor for the left rear wheel (43), and The value range of is [0, 1], b represents the wheelbase between the left rear wheel 43 and the right rear wheel 44, and ΔF r This represents the tire force increment of the right rear wheel 44. In equation (4), ΔM l_mot This represents the change in drive torque of the left rear wheel 43, r. l This represents the tire radius of the left rear wheel (43), ΔM. r_mot This represents the change in drive torque of the right rear wheel 44, r. r This indicates the tire radius of the right rear wheel (44).

[0071] In one embodiment, such as Figure 6 As shown, the controller determines the change in drive torque ΔM of the left rear wheel 43. l_mot The change in drive torque ΔM of the right rear wheel 44 r_mot Then, motor torque control signals are output to the motor controllers of the left rear wheel drive motor and the right rear wheel drive motor, so that the difference between the driving torques output by the left rear wheel drive motor and the right rear wheel drive motor can be increased by the two motor controllers respectively. Then, the driving torque output by the left rear wheel drive motor and the driving torque output by the right rear wheel drive motor at the second moment can be obtained by the following equations (5) and (6) respectively.

[0072]

[0073] In equation (5), M l_act This represents the drive torque output by the left rear wheel drive motor at the second moment, M. l This represents the driving torque output by the left rear wheel drive motor at the first moment. In equation (6), M r_act This indicates the drive torque output by the right rear wheel drive motor at the second moment, M. r This indicates the drive torque output by the right rear wheel drive motor at the first moment. The drive torque output at the second moment is based on the drive torque output at the first moment, with the corresponding change in drive torque increased or decreased according to the offset direction of the electric vehicle 01.

[0074] In one embodiment, the control method provided by the present application specifically includes: when the lateral offset of the electric vehicle at the second moment is a first lateral offset greater than the first preset lateral offset, adjusting the difference between the driving torques of the left wheel and the right wheel to increase to a first difference after the second moment; when the lateral offset of the electric vehicle at the second moment is a second lateral offset greater than the first lateral offset, adjusting the difference between the driving torques of the left wheel and the right wheel to increase to a second difference after the second moment, and the second difference is greater than the first difference.

[0075] Combined with Figure 5 Taking the offset direction of the electric vehicle 01 shown as an example, still taking the left rear wheel 43 and the right rear wheel 44. Combining the above formulas (1) to (6), it can be seen that when the lateral offset l is larger, the corresponding yaw control torque M Zt is larger. According to this yaw control torque M Zt the calculated tire force increment ΔF and the change amount ΔM of the driving torque of the drive motor mot are larger. Let l1 and l2 represent the first lateral offset and the second lateral offset respectively, and ΔM mot1 and ΔM mot2 represent the first difference and the second difference respectively. Then when l1 < l2, ΔM mot1 < ΔM mot2 . In this way, according to the actual deviation situation and degree of the electric vehicle 01, the driving torques of the left wheel and the right wheel of the electric vehicle 01 are adjusted, so that the difference between the driving torques of the left wheel and the right wheel of the electric vehicle 01 increases with the increase of the lateral offset, and the control process of suppressing the deviation of the electric vehicle 01 is shortened as much as possible, thereby improving the control efficiency of suppressing the deviation of the electric vehicle 01.

[0076] In one embodiment, the control method provided by the present application specifically includes: at the second moment, when the leftward lateral offset of the electric vehicle 01 is greater than the first preset lateral offset, adjusting the driving torque of the left wheel to be greater than that of the right wheel; at the second moment, when the rightward lateral offset of the electric vehicle is greater than the first preset lateral offset, adjusting the driving torque of the right wheel to be greater than that of the left wheel.

[0077] Combined with Figure 5The offset direction of the electric vehicle 01 is shown. At the second moment, the lateral offset amount l of the electric vehicle 01 to the left is greater than the first preset lateral offset amount, indicating that the electric vehicle 01 is currently offset to the left and the offset amount is large. The controller can actively adjust the driving torque of the left side wheel to be greater than the driving torque of the right side wheel. For example, the controller actively adjusts the driving torque of the left rear wheel 43 to be greater than the driving torque of the right rear wheel 44, so as to cause the electric vehicle 01 to have an expected offset to the right in the continuous driving of the electric vehicle 01, thereby achieving the purpose of inhibiting the electric vehicle 01 from deviating. In a possible implementation, the controller can actively increase the driving torque of the left rear wheel 43 and actively reduce the driving torque of the right rear wheel 44, or the controller can only actively increase the driving torque of the left rear wheel 43, or the controller can only actively reduce the driving torque of the right rear wheel 44, which is not limited in the embodiments of the present application.

[0078] Figure 5 For a schematic diagram of the electric vehicle 01 deviating to the left, the control process of the electric vehicle 01 deviating to the right is similar, which will not be described here.

[0079] In an embodiment, the control method provided by the present application specifically includes: at the second moment, the lateral offset amount of the electric vehicle to the left is greater than the first preset lateral offset amount, the driving torque of the left side wheel is adjusted to increase and the driving torque of the right side wheel is adjusted to decrease; at the second moment, the lateral offset amount of the electric vehicle to the right is greater than the first preset lateral offset amount, the driving torque of the right side wheel is adjusted to increase and the driving torque of the left side wheel is adjusted to decrease.

[0080] In combination Figure 5 The offset direction of the electric vehicle 01 is shown. At the second moment, the lateral offset amount l of the electric vehicle 01 to the left is greater than the first preset lateral offset amount, the controller actively adjusts the driving torque of the left rear wheel 43 to increase and the driving torque of the right rear wheel 44 to decrease. For example, the controller actively adjusts the driving torque M l ΔM l_mot of the left rear wheel driving motor output to increase and actively adjusts the driving torque M r ΔM r_mot of the right rear wheel driving motor output to decrease. The adjusted driving torque of the left rear wheel driving motor output is M l_act =M l +ΔM l_mot , and the adjusted driving torque of the right rear wheel driving motor output is M r_act =M r -ΔM r_mot . The control process of the electric vehicle 01 deviating to the right is similar, which will not be described here.

[0081] In one embodiment, the control method provided in this application specifically includes: at a second moment, when the leftward lateral offset of the electric vehicle is greater than a first preset lateral offset, adjusting the increase in the driving torque of the left wheel to equal the decrease in the driving torque of the right wheel; at a second moment, when the rightward lateral offset of the electric vehicle is greater than the first preset lateral offset, adjusting the increase in the driving torque of the right wheel to equal the decrease in the driving torque of the left wheel.

[0082] Combination Figure 5 As shown in equations (3) and (4) above, without considering special road conditions, when electric vehicle 01 shifts to the left, the increase in the driving torque of the left wheel is equal to the decrease in the driving torque of the right wheel. In one example, the above allocation factor... The value is 0.5, which means that the tire force increment ΔF is evenly distributed between the left and right rear wheels. The tire force increment ΔF of the left rear wheel is 43. l The tire force increment ΔF of the right rear wheel 44 r Equal, the tire radius r of the left rear wheel is 43. l The tire radius r of the right rear wheel is 44. r If they are equal, then the increase in the driving torque of the left rear wheel 43 is ΔM. l_mot With ΔM r_mot The decrease in drive torque of the right rear wheel 44 is equal. The control process for the electric vehicle 01 to veer to the right is similar and will not be described in detail here.

[0083] The following is still in the format of Figure 5 For example, combined with Figure 8 and Figure 9 This section explains the adjustment process of the driving torque of the left and right wheels of electric vehicle 01 under special road conditions.

[0084] In one embodiment, when the electric vehicle is located on a side slope road surface, the control method provided in this application specifically includes: at a second moment, when the leftward lateral offset of the electric vehicle is greater than a first preset lateral offset and the height of the left wheel is greater than the height of the right wheel, adjusting the increase value of the driving torque of the left wheel to be less than the decrease value of the driving torque of the right wheel; at the second moment, when the leftward lateral offset of the electric vehicle is greater than the first preset lateral offset and the height of the left wheel is less than the height of the right wheel, adjusting the increase value of the driving torque of the left wheel to be greater than the decrease value of the driving torque of the right wheel.

[0085] like Figure 8 As shown, when an electric vehicle is on a side slope road, the slope angle θ bThe center of mass of the electric vehicle 01 will be shifted, which will change the vertical load acting on the wheels of the electric vehicle 01. The greater the vertical load, the greater the driving force required for the wheel to travel, the greater the torque threshold of the driving motor driving the wheel, and the greater the output torque of the driving motor driving the wheel. The torque threshold is the torque range in which the driving motor operates normally. When the driving torque output by the driving motor exceeds the torque threshold, the motor controller of the electric vehicle will adjust the driving torque output by the driving motor to avoid overload or damage and ensure driving safety.

[0086] In combination Figure 5 The direction of the shift of the electric vehicle 01 is shown, and when the electric vehicle 01 travels to the side slope, the left rear wheel 43 and the right rear wheel 44 are taken as examples. If the height of the left rear wheel 43 is greater than the height of the right rear wheel 44, it indicates that the left rear wheel 43 of the current electric vehicle 01 is on the slope, and the right rear wheel 44 is below the slope. The center of mass of the electric vehicle 01 will move to the side of the electric vehicle 01 below the slope, so that the vertical load of the right rear wheel 44 increases, causing the dynamic radius of the right rear wheel 44 to decrease, that is, the tire radius r r of the right rear wheel 44 will temporarily decrease, and the tire force increment AF r of the right rear wheel 44 will become larger. As can be seen from the above formula (4), the change amount AM r_mot of the driving torque of the right rear wheel 44 will also become larger, and relatively, the change amount AM l_mot of the driving torque of the left rear wheel 43 will decrease, that is, AM r_mot > AM l_mot .

[0087] Similarly, if the height of the left rear wheel 43 is less than the height of the right rear wheel 44, it indicates that the left rear wheel 43 of the current electric vehicle 01 is below the slope, and the right rear wheel 44 is on the slope. The center of mass of the electric vehicle 01 will move to the side of the electric vehicle 01 below the slope, so that the vertical load of the left rear wheel 43 increases, causing the dynamic radius of the left rear wheel 43 to decrease, that is, the tire radius r l of the left rear wheel 43 will temporarily decrease, and the tire force increment AF l of the left rear wheel 43 will become larger. As can be seen from the above formula (4), the change amount AM l_mot of the driving torque of the left rear wheel 43 will also become larger, and relatively, the change amount AM r_mot of the driving torque of the right rear wheel 44 will decrease, that is, AM r_mot < AM l_mot .

[0088] The control process of the electric vehicle 01 running to the right is similar, which will not be described here.

[0089] In one embodiment, when the coefficients of adhesion between the left and right wheels of an electric vehicle and the road surface are different, the control method provided in this application specifically includes: at a second moment, when the leftward lateral offset of the electric vehicle is greater than a first preset lateral offset and the coefficient of adhesion between the left wheel and the road surface is greater than the coefficient of adhesion between the right wheel and the road surface, adjusting the increase in the driving torque of the left wheel to be greater than the decrease in the driving torque of the right wheel; at a second moment, when the leftward lateral offset of the electric vehicle is greater than the first preset lateral offset and the coefficient of adhesion between the left wheel and the road surface is less than the coefficient of adhesion between the right wheel and the road surface, adjusting the increase in the driving torque of the left wheel to be less than the decrease in the driving torque of the right wheel.

[0090] like Figure 9 As shown, on a split-type road surface, the coefficient of adhesion between the wheel and the road surface causes a change in the tire force boundary of that wheel, thus affecting the yaw torque distribution factor. Changes occur. Among them, split road surfaces refer to road surfaces with different adhesion coefficients on both sides, with one side having a higher adhesion coefficient and the other side having a lower adhesion coefficient.

[0091] Combination Figure 5 The deflection direction of the electric vehicle 01 is shown. Taking the left rear wheel 43 and right rear wheel 44 as an example, when the electric vehicle 01 travels on a split road surface, if the coefficient of friction between the left rear wheel 43 and the road surface is greater than that between the right rear wheel 44 and the road surface, it means that more power needs to be distributed to the tire with the higher coefficient of friction, i.e., to the left rear wheel 43. In one possible implementation, the coefficient of friction can be obtained by the electric vehicle sensor of the electric vehicle 01. The electric vehicle sensor can measure the coefficient of friction μ between the left rear wheel 43 and the road surface. l And the coefficient of adhesion μ between the right rear wheel 44 and the road surface r Transmitted to the controller. The controller then uses the received adhesion coefficient μ. l and μ r When calculating the tire force increment of the two rear wheels, the yaw torque distribution factor of the left rear wheel 43 is adjusted. A value greater than 0.5 results in a yaw torque distribution factor of 44 for the right rear wheel. The value is less than 0.5, thus distributing the larger tire force increment to the left rear wheel 43 and the smaller tire force increment to the right rear wheel 44. Furthermore, based on the tire force increment and the tire radius r of the left rear wheel 43... l And the tire radius r of the right rear wheel (43). r When calculating the changes in drive torque output by the left rear wheel drive motor and the right rear wheel drive motor, the increase in drive torque output by the left rear wheel should be greater than the decrease in drive torque output by the right rear wheel, i.e., ΔM. l_mot >ΔM r_motSimilarly, when the adhesion coefficient of the left rear wheel 43 to the road surface is less than the adhesion coefficient of the right rear wheel 44 to the road surface, the increase value of the driving torque of the left rear wheel is less than the decrease value of the driving torque of the right rear wheel, i.e., AM l_mot <ΔM r_mot .

[0092] The control process of the electric vehicle 01 running to the right is similar, and thus is not described herein.

[0093] In an embodiment, the control method provided in the present application further includes: at a third time after the second time, gradually reducing the difference between the driving torque of the left side wheel and the driving torque of the right side wheel. In a possible implementation, at the third time, the controller can detect that the lateral deviation and the heading angle deviation of the electric vehicle 01 are reduced to the normal range, and actively adjusts the difference between the driving torque of the left side wheel and the driving torque of the right side wheel to gradually reduce, so as to restore the driving torque of the left side wheel and the driving torque of the right side wheel to a balanced state, and timely respond to the driving demand of the user operation in the subsequent driving of the electric vehicle 01.

[0094] In an embodiment, at the third time, the steering wheel angle of the electric vehicle 01 is greater than an angle threshold or the opening degree of the brake pedal of the electric vehicle 01 is greater than a preset brake pedal opening degree.

[0095] Wherein, the steering wheel angle greater than the angle threshold indicates that the user operates the steering wheel and hopes to control the electric vehicle 01 to turn or end the straight driving state. The opening degree of the brake pedal greater than the preset brake pedal opening degree indicates that the user steps on the brake pedal and hopes to control the speed of the electric vehicle 01 to reduce or stop. Then the controller gradually reduces the yaw control torque to end the deviation suppression of the electric vehicle 01. In an example, at the third time, the controller sends an exit signal to the motor controller of the left side wheel and the motor controller of the right side wheel after detecting that the steering wheel angle is greater than the angle threshold or the opening degree of the brake pedal is greater than the preset brake pedal opening degree, and the motor controller of the left side wheel and the motor controller of the right side wheel reduce the difference between the driving torque of the left side wheel and the driving torque of the right side wheel after receiving the exit signal.

[0096] In an embodiment, the control method provided in the present application specifically includes: at the second time, increasing the difference between the driving torque of the left side wheel and the driving torque of the right side wheel at a first rate; and at the third time, reducing the difference between the driving torque of the left side wheel and the driving torque of the right side wheel at a second rate less than the first rate.

[0097] In combination with Figure 5The offset direction of the electric vehicle 01 is shown. At the second time, the controller actively adjusts the driving torque of the left rear wheel 43 to be greater than the driving torque of the right rear wheel 44, and adjusts the difference between the driving torque of the left rear wheel 43 and the driving torque of the right rear wheel 44 to increase at a first rate. At the third time, the controller actively adjusts the difference between the driving torque of the left rear wheel 43 and the driving torque of the right rear wheel 44 to decrease at a second rate, and the second rate is less than the first rate, so that the driving torque of the left rear wheel 43 and the driving torque of the right rear wheel 44 can return to the balanced state at a relatively gentle rate, avoiding the jerk caused by the rapid increase or decrease of the driving torque, and improving the driving experience of the user.

[0098] In an embodiment, the control method provided by the present application specifically includes: during the driving process of the electric vehicle at a first vehicle speed, adjusting the difference between the driving torque of the left side wheel and the driving torque of the right side wheel to decrease when the steering wheel angle of the electric vehicle is greater than a first angle threshold, at this time, the time when the steering wheel angle is greater than the first angle threshold is the third time; during the driving process of the electric vehicle at a second vehicle speed, adjusting the difference between the driving torque of the left side wheel and the driving torque of the right side wheel to decrease when the steering wheel angle of the electric vehicle is greater than a second angle threshold, at this time, the time when the steering wheel angle is greater than the second angle threshold is the third time; the first vehicle speed is less than the second vehicle speed, and the first angle threshold is greater than the second angle threshold.

[0099] Wherein, the angle threshold is the angle threshold corresponding to the vehicle speed. In a possible implementation, the controller can configure multiple angle thresholds according to the correspondence between the set vehicle speed and the angle threshold. For example, when the vehicle speed of the electric vehicle is greater than a preset vehicle speed and less than or equal to a first vehicle speed, the first angle threshold corresponds, and when the steering wheel angle is greater than the first angle threshold, it indicates that the user operates the steering wheel to control the electric vehicle 01 to end the suppression of running deviation; when the vehicle speed of the electric vehicle is greater than the first vehicle speed and less than or equal to a second vehicle speed, the second angle threshold less than the first angle threshold corresponds, and when the steering wheel angle is greater than the second angle threshold and less than the first angle threshold, it indicates that the user operates the steering wheel to control the electric vehicle 01 to end the suppression of running deviation.

[0100] In one embodiment, the control method provided by this application further includes: at a second moment, if the lateral deviation of the electric vehicle is greater than a second preset lateral deviation, an alarm signal is output to the user. In one possible implementation, at the second moment, during the process of suppressing the deviation of the electric vehicle 01, the controller can calculate and evaluate the heading angle deviation and lateral deviation in real time, and output the calculated heading angle deviation and lateral deviation to the vehicle display screen or external device so that the user can be informed of the deviation suppression status of the electric vehicle 01 in a timely manner. If, at the second moment, the lateral deviation of the electric vehicle 01 exceeds the second preset lateral deviation, it indicates that during the process of suppressing the deviation of the electric vehicle 01, the lateral deviation of the electric vehicle 01 has failed to decrease as expected, or the lateral deviation of the electric vehicle 01 is still increasing. In this case, an alarm signal needs to be issued to the user in a timely manner to remind the user to pay attention to the current deviation status of the electric vehicle 01.

[0101] The following is combined Figure 10 The process of suppressing electric vehicle deviation is explained in detail with specific embodiments. Taking electric vehicle 01 deviating to the left as an example.

[0102] The period from before time t1 to time t1 (the first time point) is the straight-line phase. Before time t1, the electric vehicle is traveling straight, the user does not turn the steering wheel or the steering wheel angle is less than the steering angle threshold R1, and the user does not press the brake pedal or the brake pedal opening is less than the preset brake pedal opening L1. The drive torque M of the left rear wheel is... l_act =M l And the drive torque M of the right rear wheel r_act =M r .

[0103] From time t1 to time t2 (the second time point), the vehicle is still in the straight-line driving phase. During this phase, the electric vehicle is traveling straight, the user does not turn the steering wheel or the steering wheel angle is less than the steering angle threshold R1, and the user does not depress the brake pedal or the brake pedal opening is less than the preset brake pedal opening L1. The drive torque M of the left rear wheel... l_act =M l And the drive torque M of the right rear wheel r_act =M r In other words, before time t2, the electric vehicle veers off course while traveling straight.

[0104] The period from time t2 (second moment) to time t4 (third moment) is the stage for adjusting the drive torque. From time t2 to time t3, the drive torque of the left rear wheel increases by ΔM. l_mot The drive torque of the right rear wheel decreased by ΔM r_mot At time t3, the drive torque M of the left rear wheel is... l_act =M l +ΔM l_mot， Drive torque M of the right rear wheelr_act = M r - ΔM r_mot From the moment t3 to the moment t4, the left rear wheel rotates under the action of the increased driving torque, and the right rear wheel rotates under the action of the reduced driving torque, so that the electric vehicle 01 generates the expected deviation, thereby offsetting the deviation of the electric vehicle, and achieving the purpose of correcting the deviation of the electric vehicle. That is, the moment t2 to the moment t4 is the process of suppressing the deviation of the electric vehicle.

[0105] From the moment t4 (the third moment) to the moment t5, the electric vehicle 01 ends the process of suppressing the deviation. At the moment t4, the user rotates the steering wheel so that the steering wheel angle is greater than the angle threshold R1, or the user steps on the brake pedal with an opening greater than the preset brake pedal opening L1, the electric vehicle 01 exits the control process of suppressing the deviation, the driving torque M l_act of the left rear wheel gradually decreases to M l , and the driving torque M r_act of the right rear wheel gradually decreases to M r . That is, the moment t4 to the moment t5 is the process of the electric vehicle 01 exiting the process of suppressing the deviation. After the moment t5, the electric vehicle 01 normally responds to the driving operation of the user.

[0106] Figure 11 A process for correcting the deviation of the electric vehicle provided by the embodiment of the application is shown. The specific details of the method for correcting the deviation of the electric vehicle provided by the embodiment of the application are as described above, and will not be described here.

[0107] During the straight driving of the electric vehicle, the controller of the electric vehicle uses the steering wheel angle signal input by the user, the yaw rate signal input by the yaw rate sensor, and the vehicle speed signal input by the vehicle speed sensor to determine whether the current state of the electric vehicle needs to actively start the deviation suppression. If the deviation suppression needs to be started, the controller activates the deviation suppression function, and calculates the deviation posture of the electric vehicle based on the input signals, that is, calculates the heading angle deviation and the lateral deviation.

[0108] If the heading angle deviation is greater than the preset heading angle deviation, or the lateral deviation is greater than the first preset lateral deviation, the required yaw control moment is calculated through the heading angle deviation PID controller and the lateral deviation PID controller respectively. The controller differentially distributes the driving torque according to the calculated yaw control moment, and controls the corresponding driving motor to output torque through the motor controller.

[0109] The embodiment of the application also provides a controller for an electric vehicle, which is used to execute the control method for suppressing the deviation of the electric vehicle provided in the above embodiments.

[0110] The embodiment of the application further provides an electric vehicle, which comprises two left wheels, two right wheels and a distributed power assembly, the distributed power assembly comprising two driving motors and a controller, the controller being configured to control one driving motor to drive one left wheel and to control the other driving motor to drive one right wheel coaxial with the one left wheel; the controller being configured to control the electric vehicle to suppress deviation after deviation during straight driving of the electric vehicle, and the controller is specifically configured to: in response to a lateral deviation of the electric vehicle being greater than a first preset lateral deviation, increase a difference between torques output by the two driving motors during driving of the electric vehicle at a vehicle speed greater than a preset vehicle speed.

[0111] Finally, it should be noted that the above description is merely a specific implementation of the present application, but the protection scope of the present application is not limited thereto, and any changes or replacements within the technical scope disclosed in the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A control method for suppressing the deviation of electric vehicles, characterized in that, The control method is used to control the electric vehicle to suppress deviation after it veers off course during straight-line travel. The control method includes: At the first moment, the control drive system outputs drive torque to the left and right wheels of the electric vehicle; At a second moment after the first moment, the difference between the driving torque of the left wheel and the driving torque of the right wheel is increased. Wherein, at both the first and second moments, the steering wheel angle of the electric vehicle is less than the angle threshold; At the second moment, the leftward lateral offset of the electric vehicle is greater than the first preset lateral offset and the adhesion coefficient between the left wheel and the road surface is greater than the adhesion coefficient between the right wheel and the road surface. The increase in the driving torque of the left wheel is greater than the decrease in the driving torque of the right wheel. At the second moment, the leftward lateral offset of the electric vehicle is greater than the first preset lateral offset and the adhesion coefficient between the left wheel and the road surface is less than the adhesion coefficient between the right wheel and the road surface. Therefore, the increase in the driving torque of the left wheel is less than the decrease in the driving torque of the right wheel.

2. The control method according to claim 1, characterized in that, At the second moment, the speed of the electric vehicle is greater than a preset speed, the lateral offset of the electric vehicle is greater than a first preset lateral offset, or the heading angle offset of the electric vehicle is greater than a preset heading angle offset.

3. The control method according to claim 2, characterized in that, The control method specifically includes: At the second moment, the leftward lateral offset of the electric vehicle is greater than the first preset lateral offset, and the driving torque of the left wheel is adjusted to be greater than the driving torque of the right wheel. At the second moment, the lateral offset to the right of the electric vehicle is greater than the first preset lateral offset, and the driving torque of the right wheel is adjusted to be greater than the driving torque of the left wheel.

4. The control method according to claim 2, characterized in that, The control method specifically includes: At the second moment, if the leftward lateral offset of the electric vehicle is greater than the first preset lateral offset, the driving torque of the left wheel is increased and the driving torque of the right wheel is decreased. At the second moment, if the lateral offset to the right of the electric vehicle is greater than the first preset lateral offset, the driving torque of the right wheel is increased and the driving torque of the left wheel is decreased.

5. The control method according to claim 3 or 4, characterized in that, The control method specifically includes: At the second moment, the leftward lateral offset of the electric vehicle is greater than the first preset lateral offset, and the increase in the driving torque of the left wheel is adjusted to be equal to the decrease in the driving torque of the right wheel. At the second moment, if the lateral offset to the right of the electric vehicle is greater than the first preset lateral offset, the increase in the driving torque of the right wheel is adjusted to be equal to the decrease in the driving torque of the left wheel.

6. The control method according to claim 3 or 4, characterized in that, The control method specifically includes: At the second moment, the leftward lateral offset of the electric vehicle is greater than the first preset lateral offset and the height of the left wheel is greater than the height of the right wheel, so the increase in the driving torque of the left wheel is less than the decrease in the driving torque of the right wheel. At the second moment, the leftward lateral offset of the electric vehicle is greater than the first preset lateral offset and the height of the left wheel is less than the height of the right wheel, so the increase in the driving torque of the left wheel is greater than the decrease in the driving torque of the right wheel.

7. The control method according to claim 2, characterized in that, The control method specifically includes: When the lateral offset of the electric vehicle at the second moment is a first lateral offset that is greater than the first preset lateral offset, the difference between the driving torque of the left wheel and the driving torque of the right wheel is increased to the first difference after the second moment. When the lateral offset of the electric vehicle at the second moment is a second lateral offset that is greater than the first lateral offset, the difference between the driving torque of the left wheel and the driving torque of the right wheel is increased to a second difference after the second moment, and the second difference is greater than the first difference.

8. The control method according to claim 1, characterized in that, The control method further includes: At a third time point following the second time point, the difference between the driving torque of the left wheel and the driving torque of the right wheel is reduced.

9. The control method according to claim 8, characterized in that, At the third moment, the steering wheel angle of the electric vehicle is greater than the steering angle threshold or the opening of the brake pedal of the electric vehicle is greater than the preset brake pedal opening.

10. The control method according to claim 8, characterized in that, The control method specifically includes: At the second moment, the difference between the driving torque of the left wheel and the driving torque of the right wheel is increased at a first rate. At the third moment, the difference between the driving torque of the left wheel and the driving torque of the right wheel is adjusted to decrease at a second rate less than the first rate.

11. The control method according to claim 8, characterized in that, The control method specifically includes: During the driving process of the electric vehicle at a first speed, when the steering wheel angle of the electric vehicle is greater than a first angle threshold, the difference between the driving torque of the left wheel and the driving torque of the right wheel is reduced, wherein the moment when the steering wheel angle is greater than the first angle threshold is the third moment. During the operation of the electric vehicle at a second speed, at a moment when the steering wheel angle of the electric vehicle is greater than a second angle threshold, the difference between the driving torque of the left wheel and the driving torque of the right wheel is reduced at the third moment, wherein the moment when the steering wheel angle is greater than the second angle threshold is the third moment. The first vehicle speed is less than the second vehicle speed, and the first turning angle threshold is greater than the second turning angle threshold.

12. The control method according to claim 2, characterized in that, The control method further includes: At the second moment, if the lateral offset of the electric vehicle is greater than the second preset lateral offset, an alarm signal is output to the user.

13. A controller for an electric vehicle, characterized in that, The controller is used to perform the method as described in any one of claims 1-12.

14. An electric vehicle, characterized in that, The electric vehicle includes two left wheels, two right wheels, and a distributed powertrain. The distributed powertrain includes two drive motors and a controller. The controller is used to control one of the drive motors to drive one left wheel and to control the other drive motor to drive a right wheel that is coaxial with one of the left wheels. The controller is used to control the electric vehicle to suppress deviation after it veers off course while traveling straight. Specifically, the controller is used to: During the process of the electric vehicle traveling at a speed greater than a preset speed, in response to the lateral offset of the electric vehicle being greater than a first preset lateral offset, the difference in torque output by the two drive motors is increased. At the second moment, the leftward lateral offset of the electric vehicle is greater than the first preset lateral offset and the adhesion coefficient between the left wheel and the road surface is greater than the adhesion coefficient between the right wheel and the road surface. Therefore, the increase in the driving torque of the left wheel is greater than the decrease in the driving torque of the right wheel. At the second moment, the leftward lateral offset of the electric vehicle is greater than the first preset lateral offset and the adhesion coefficient between the left wheel and the road surface is less than the adhesion coefficient between the right wheel and the road surface. Therefore, the increase in the driving torque of the left wheel is less than the decrease in the driving torque of the right wheel.

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