Control method for restraining deviation of electric vehicle, controller and electric vehicle

Abstract

The invention discloses a control method for restraining deviation of an electric vehicle, a controller and the electric vehicle, and relates to the technical field of new energy automobiles. The control method is used for controlling the electric vehicle to restrain deviation after the electric vehicle deviates in the straight running process and comprises the steps that at the first moment, a driving system is controlled to output driving torque to a left wheel and a right wheel of the electric vehicle; at a second moment after the first moment, the difference value between the driving torque of the left wheel and the driving torque of the right wheel is adjusted to be increased; wherein the steering angle of the steering wheel of the electric vehicle at the first moment and the second moment is smaller than the steering angle threshold value. In this way, deviation of the electric vehicle in the straight running process can be restrained, 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 and a controller for suppressing deviation of an electric vehicle, and an electric vehicle. Background Art

[0002] When an electric vehicle is driving straight, if the speed is high and the driver does not turn the steering wheel, the direction and trajectory of the electric vehicle will deviate unexpectedly, causing the electric vehicle to run off the track. This is due to the difference in accuracy between the output torque of the left and right motors of the distributed drive electric vehicle, or the inconsistent wear of the left and right tires, which will reduce the stability and safety of the electric vehicle.

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

[0004] Based on this, how to effectively prevent electric vehicles from running off the track during straight driving and improve the driving safety of electric vehicles has become an urgent problem to be solved. Summary of the invention

[0005] The present application provides a control method, a controller, and an electric vehicle for preventing an electric vehicle from running off the track, which are used to prevent the electric vehicle from running off the track during straight driving and improve the driving safety of the electric vehicle.

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

[0007] In a first aspect, a control method for suppressing an electric vehicle from running off the track is provided, the control method being used to control the electric vehicle to suppress the electric vehicle from running off the track after the electric vehicle runs off the track during straight travel, the control method comprising: at a first moment, controlling a drive system to output a driving torque to a left wheel and a right wheel of the electric vehicle; at a second moment after the first moment, adjusting the difference between the driving torque of the left wheel and the driving torque of the right wheel to increase; wherein, at the first moment and the second moment, the steering wheel angle of the electric vehicle is less than an angle threshold, indicating that the user has not turned the steering wheel or has turned the steering wheel at a small angle, and the electric vehicle is in a straight travel state.

[0008] In the above technical scheme, at the first moment, the electric vehicle is still deviating, and the difference in the output driving torque of the left wheel and the right wheel is relatively small. At the second moment after the first moment, without the need for the user to turn the steering wheel to control the electric vehicle to adjust the driving direction, the control method provided in the embodiment of the present application can actively adjust the difference between the driving torque of the left wheel and the driving torque of the right wheel to increase. When the difference in the output driving torque of the left wheel and the right wheel is large, the driving force received by the left wheel and the right wheel will be quite different. As a result, during the continued driving of the electric vehicle, due to the inconsistent driving force of the wheels on both sides, the electric vehicle will have an expected deviation, which can be offset by the deviation of the electric vehicle, thereby ultimately achieving the purpose of suppressing the deviation of the electric vehicle and improving the driving safety of the electric vehicle.

[0009] In any possible implementation of the first aspect, at the second moment, the speed of the electric vehicle is greater than the preset speed, the lateral offset of the electric vehicle is greater than the first preset lateral offset, or the heading angle offset of the electric vehicle is greater than the preset heading angle offset. In the above possible implementations, the preset speed, the first preset lateral offset, and the preset heading angle offset are trigger thresholds for suppressing the electric vehicle from running off. When the speed of the electric vehicle is greater than the preset speed, it indicates that the electric vehicle 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 has deviated during high-speed straight driving and the offset is large, and the electric vehicle needs to be suppressed from running off. In this way, by setting the preset speed, the first preset lateral offset, and the preset heading angle offset, it is possible to timely detect whether the electric vehicle has deviated and needs to be suppressed, thereby improving the driving safety of the electric vehicle.

[0010] In any possible implementation of the first aspect, the control method specifically includes: at the second moment, the lateral offset to the left 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. The above possible implementation method adaptively adjusts the magnitude relationship of the driving torque of the wheels on both sides according to the offset direction of the electric vehicle, and controls the electric vehicle to deviate in the opposite direction of the deviation as expected, thereby effectively suppressing the deviation of the electric vehicle and improving the driving safety of the electric vehicle.

[0011] In any possible implementation of the first aspect, the control method specifically includes: at the second moment, the lateral offset to the left of the electric vehicle is greater than the first preset lateral offset, adjusting the driving torque of the left wheel to increase and adjusting the driving torque of the right wheel to decrease; at the second moment, the lateral offset to the right of the electric vehicle is greater than the first preset lateral offset, adjusting the driving torque of the right wheel to increase and adjusting the driving torque of the left wheel to decrease. The above possible implementation method, according to the offset direction of the electric vehicle, adaptively adjusts the magnitude relationship of the driving torque of the wheels on both sides, controls the electric vehicle to deviate in the opposite direction of the deviation as expected, thereby effectively suppressing the deviation of the electric vehicle and improving the driving safety of the electric vehicle.

[0012] In any possible implementation of the first aspect, the control method specifically includes: at the second moment, the lateral offset to the left 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, the lateral offset to the right of the electric vehicle is greater than the first preset lateral offset, and 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. The above possible implementation method adaptively adjusts the magnitude relationship of the driving torque of the wheels on both sides according to the offset direction of the electric vehicle, and controls the electric vehicle to deviate in the opposite direction of the deviation as expected, thereby effectively suppressing the deviation of the electric vehicle and improving the driving safety of the electric vehicle.

[0013] In any possible implementation of the first aspect, the control method specifically includes: at the second moment, the lateral offset to the left 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, and the increase in the driving torque of the left wheel is adjusted to be less than the decrease in the driving torque of the right wheel; at the second moment, the lateral offset to the left 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, and the increase in the driving torque of the left wheel is adjusted to be greater than the decrease in the driving torque of the right wheel. The above possible implementation, combined with the offset direction of the electric vehicle, can adaptively adjust the magnitude relationship of the driving torque of the wheels on both sides on a road with complex road conditions (for example, a side slope road), so as to control the electric vehicle to deviate in the opposite direction of the deviation as expected, thereby effectively suppressing the deviation of the electric vehicle and improving the driving safety of the electric vehicle.

[0014] In any possible implementation of the first aspect, the control method specifically includes: at the second moment, the lateral offset to the left 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, 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; at the second moment, the lateral offset to the left 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, 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. The above possible implementation, combined with the offset direction of the electric vehicle, on a road with complex road conditions (for example, on a split road), adaptively adjusts the magnitude relationship of the driving torque of the wheels on both sides, can control the electric vehicle to deviate in the opposite direction of the deviation as expected, thereby effectively suppressing the deviation of the electric vehicle and improving the driving safety of the electric vehicle.

[0015] In any possible implementation of the first aspect, the control method 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 torque of the left wheel and the driving torque of the right wheel to increase 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 greater than the first lateral offset, adjusting the difference between the driving torque of the left wheel and the driving torque of the right wheel to increase to the second difference after the second moment, and the second difference is greater than the first difference. In the above possible implementation, the driving torque of the left wheel and the driving torque of the right wheel of the electric vehicle are adjusted according to the actual deviation 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, and the control process of suppressing the deviation of the electric vehicle is shortened as much as possible, thereby improving the control efficiency of suppressing the deviation of the electric vehicle and improving the driving experience of the electric vehicle.

[0016] In any possible implementation of the first aspect, the control method further includes: at a third moment after the second moment, adjusting the difference between the driving torque of the left wheel and the driving torque of the right wheel to decrease. In the above possible implementation, at the third moment, the control method provided by the embodiment of the present application can detect that the lateral offset and the heading angle offset of the electric vehicle are reduced to a 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 that the driving torque of the left wheel and the driving torque of the right wheel are restored to a balanced state, and in the subsequent driving of the electric vehicle, the driving needs of the user's operation are responded to in a timely manner, thereby improving the driving experience of the electric vehicle.

[0017] In any possible implementation of the first aspect, at the third moment, the steering wheel angle of the electric vehicle is greater than the angle threshold or the opening of the brake pedal of the electric vehicle is greater than the preset brake pedal opening. In the above possible implementation, the steering wheel angle is greater than the angle threshold, indicating that the user has operated the steering wheel and hopes to control the electric vehicle to turn or end the straight state. The opening of the brake pedal is greater than the preset brake pedal opening, indicating that the user has stepped on the brake pedal and hopes to control the electric vehicle to reduce its speed or stop. At the third moment, the electric vehicle can also respond to the user's operation in a timely manner, thereby improving the driving experience of the electric vehicle.

[0018] In any possible implementation of the first aspect, the control method specifically includes: at the second moment, adjusting the difference between the driving torque of the left wheel and the driving torque of the right wheel to increase at a first rate; at the third moment, adjusting the difference between the driving torque of the left wheel and the driving torque of the right wheel to decrease at a second rate less than the first rate. In the above possible implementation, at the second moment, first actively adjust the difference between the driving torque of the left wheel and the driving torque of the right wheel to increase at a first rate; at the third moment, actively adjust the difference between the driving torque of the left wheel and the driving torque of the right wheel to decrease at a second rate less than the first rate, and the second rate is less than the first rate, so as to ensure that the driving torque of the left wheel and the driving torque of the right wheel can return to a balanced state at a relatively gentle rate, avoid the frustration caused by the driving torque increasing or decreasing too quickly, and improve the user's driving experience.

[0019] In any possible implementation of the first aspect, 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 the first angle threshold, the difference between the driving torque of the left wheel and the driving torque of the right wheel is adjusted to be reduced, wherein the moment when the steering wheel angle is greater than the first angle threshold is the third moment; during the driving process of the electric vehicle at a second speed, when the steering wheel angle of the electric vehicle is greater than the second angle threshold, the difference between the driving torque of the left wheel and the driving torque of the right wheel is adjusted to be reduced, 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 angle threshold is greater than the second angle threshold. In the above possible implementations, the control method provided by the embodiment of the present application can configure different angle thresholds according to different vehicle speeds, thereby timely responding to the user's operation needs according to different angle thresholds, thereby improving the user's driving experience.

[0020] In any possible implementation of the first aspect, the control method further includes: at the second moment, the lateral offset of the electric vehicle is greater than the second preset lateral offset, and outputting an alarm signal to the user. In the above possible implementation, at the second moment, the lateral offset of the electric vehicle exceeds the second preset lateral offset, indicating that in the process of suppressing the deviation of the electric vehicle, the lateral offset of the electric vehicle has not been reduced as expected, or the lateral offset of the electric vehicle is still increasing, and it is necessary to send an alarm signal to the user in time to remind the user to pay attention to the current offset 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, wherein the controller is used to execute the control method for suppressing the electric vehicle from running off the track provided in the first aspect or any possible implementation of the first aspect.

[0022] According to a third aspect, an electric vehicle is provided, comprising two left wheels, two right wheels and a distributed power assembly, wherein the distributed power assembly comprises two drive motors and a controller, wherein the controller is used to control one drive motor to drive a left wheel and to control another drive motor to drive a right wheel coaxial with a left wheel; the controller is used to control the electric vehicle to suppress deviation after the electric vehicle deviates during straight-line driving, and the controller is specifically used to: during driving of the electric vehicle at a speed greater than a preset speed, in response to a lateral offset of the electric vehicle being greater than a first preset lateral offset, control the difference in torque output by the two drive motors to increase.

[0023] It can be understood that the beneficial effects that can be achieved by the controller for an electric vehicle and the electric vehicle provided above can correspond to the beneficial effects of the control method for suppressing the deviation of the electric vehicle provided above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0025] Figure 2 A schematic diagram of the structure of an electric vehicle provided in an embodiment of the present application;

[0026] Figure 3 A schematic diagram of the structure of a four-motor distributed drive vehicle provided in an embodiment of the present application;

[0027] Figure 4 A schematic diagram of the structure of a three-motor distributed drive vehicle provided in an embodiment of the present application;

[0028] Figure 5 A schematic diagram of an electric vehicle veering 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 provided in an embodiment of the present application;

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

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

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

[0033] Fig.10 A signal timing diagram of a control method for suppressing deviation of an electric vehicle provided in an embodiment of the present application;

[0034] Fig.11 A schematic diagram of another control process for suppressing an electric vehicle from running off track provided in an embodiment of the present application. DETAILED DESCRIPTION

[0035] The following will discuss the making and use of each embodiment in detail. However, it should be understood that many applicable inventive concepts provided by this application can be implemented in a variety of specific environments. The specific embodiments discussed are only illustrative of specific ways to implement and use this application and this technology, and do not limit the scope of this application.

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

[0037] Electric vehicle deviation refers to the unexpected deviation of the driving direction and trajectory of the electric vehicle when the electric vehicle is moving straight ahead at a high speed and the user does not turn the steering wheel. For example, when a user is driving an electric vehicle on a highway, if the road conditions are good, the user will only exert slight control on the steering wheel and will not hold and turn the steering wheel at all times, which may cause the electric vehicle to deviate. This is due to the difference in accuracy of the output torque of the left and right motors of the distributed drive electric vehicle, or the inconsistent wear of the left and right tires, or the positioning differences of the four wheels of the electric vehicle, which will reduce the driving safety of the electric vehicle.

[0038] In the related art, in order to prevent the electric vehicle from deviating during straight driving, the steering system of the electric vehicle is usually used for control. Figure 1As shown, the steering system mainly includes a wire-controlled steering gear, an inertial measurement unit (IMU), a computing unit and a positioning device. The IMU is used to measure the heading angle deviation between the starting scale line and the target scale line of the electric vehicle. The positioning device is used to determine the position coordinates of the electric vehicle. The computing unit is used to calculate the lateral offset of the electric vehicle according to the heading angle deviation indicated by the heading angle information and the position coordinates of the electric vehicle, and when the lateral offset exceeds the lateral offset threshold, the median correction value of the wire-controlled steering gear is determined according to the heading angle deviation to perform median calibration on the wire-controlled steering gear, thereby correcting the straight-ahead deviation of the electric vehicle. The wire-controlled steering gear is used to receive the steering command of the computing unit and control the steering action of the electric vehicle.

[0039] In the process of using the steering system to control the electric vehicle to go straight and avoid deviation, it is necessary to calibrate the median correction value of the wire-controlled steering device. The calibration accuracy of the median correction value has a great influence on the control effect of the deviation correction of the electric vehicle. When the calibration result is inaccurate or the accuracy of the calibrated median correction value is poor, the control effect of the deviation correction of the electric vehicle will also be poor.

[0040] In view of this, the embodiments of the present application provide a control method, a controller, and an electric vehicle for suppressing deviation of an electric vehicle. The control method is used to control the electric vehicle to suppress deviation after the electric vehicle deviates during straight driving, and to control the driving system to adjust the difference between the driving torque of the left wheel and the driving torque of the right wheel, thereby effectively correcting the deviation phenomenon of the electric vehicle during straight driving and improving the driving safety of the electric vehicle.

[0041] The following will first introduce the electric vehicle provided in the embodiment of the present application in detail with reference to the accompanying drawings.

[0042] See also Figure 2 , Figure 2 This is a schematic diagram of the structure of an electric vehicle provided in an embodiment of the present 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 can also be called a powertrain, and the drive system 20 includes a motor controller 21 and a drive motor 22. The power battery 30 is used to provide electrical energy to the drive system 20. The vehicle controller 10 is used to output a torque signal to the motor controller 21. The motor controller 21 is used to control the output torque of the drive motor 22 based on the torque signal. Under the control of the motor controller 21, the drive motor 22 is used to provide driving force for the wheels of the electric vehicle 01 to rotate the wheels, thereby driving the electric vehicle 01 to travel. Optionally, the electric vehicle 01 also includes a braking system ( Figure 2 (not shown), the braking system is used to provide braking force for the wheels of the electric vehicle 01.

[0043] The functions of the vehicle controller 10 are described below in conjunction with the running state of the electric vehicle 01. The running state of the electric vehicle 01 includes 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 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 the electric energy from the power battery 30 and controls the drive motor 22 to output the torque value indicated by the torque signal, that is, the drive motor 22 provides driving force for the electric vehicle 01.

[0045] When the electric vehicle 01 is in a braking state, the drive system 20 stops driving the wheels to rotate, and the braking system is used to provide braking force for the wheels so that the electric vehicle 01 can reduce the speed under the action of the braking force. 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 a 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 electrical energy and outputs a negative torque to the wheels of the electric vehicle 01 to provide braking force to the electric vehicle 01. Among them, the output of positive torque by the drive motor 22 means that the output direction of the drive motor 22 is the same as the rotational speed direction of the drive motor 22; the output of negative torque by the drive motor 22 means that the output direction of the drive motor 22 is opposite to the rotational speed direction of the drive motor 22.

[0046] In one embodiment, if Figure 2As shown, the electric vehicle 01 also includes a domain controller 23 (domain controller unit, DCU). Compared with the vehicle controller 10, the domain controller 23 has a highly integrated feature and can integrate the functions of multiple electronic control units (electronic control units, ECU) into one controller to improve the integration of the control system and reduce the complexity of the control system. DCU can be used to integrate multiple related functions, such as power domain, chassis domain, body domain, cockpit domain and automatic driving domain, etc. These domains are responsible for different functions and control systems of the car. The controller for the electric vehicle provided in the embodiment of the present application may be a power domain controller that integrates the function of suppressing the electric vehicle from running off, or an automatic driving domain controller that integrates the function of suppressing the electric vehicle from running off, and the embodiment of the present application does not make specific restrictions on this. In one possible implementation, the domain controller 23 may be an independently integrated DCU chip, which is connected to the motor controller 21 in the drive system 20; or as Figure 2 As shown, the domain controller 23 may also be integrated inside the drive system 20 and connected to 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 embodiment of the present application can be a four-motor distributed drive vehicle (such as Figure 3 ), or a three-motor distributed drive vehicle (as shown Figure 4 shown).

[0048] In one example, if Figure 3 As shown, 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 respectively. The four drive motors include a drive motor 221, a drive motor 222, a drive motor 223 and a drive motor 224 respectively. The motor controller 211 is used to control the drive motor 221 to drive the wheel (left front wheel) 41, the motor controller 212 is used to control the drive motor 222 to drive the wheel (right front wheel) 42, the motor controller 213 is used to control the drive motor 223 to drive the wheel (left rear wheel) 43, and the motor controller 214 is used to control the drive motor 224 to drive the wheel (right rear wheel) 44.

[0049] In another example, Figure 4As shown, the electric vehicle 01 includes three motor controllers and drive motors. The three motor controllers include a motor controller 211, a motor controller 212 and a motor controller 213 respectively. The three drive motors include a drive motor 221, a drive motor 222 and a drive motor 223 respectively. The motor controller 211 is used to control the drive motor 221 to drive the wheel (left front wheel) 41 and the wheel (right front wheel) 42 at the same time, the motor controller 212 is used to control the drive motor 222 to drive the wheel (left rear wheel) 43, and the motor controller 213 is used to control the drive motor 223 to drive the wheel (right rear wheel) 44.

[0050] The architecture of the embodiment of the present application is described above. The technical solution provided by the embodiment of the present application is described in detail below in conjunction with specific embodiments.

[0051] The control method provided in the embodiment of the present application is used to control the electric vehicle 01 to suppress deviation after the electric vehicle 01 deviates during straight driving, and the relevant steps of the control method can be controlled and executed by the above-mentioned controller. The control method includes: at a first moment, controlling the drive system to output driving 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 driving torque of the left wheel and the driving torque of the right wheel to increase; wherein, at the first moment and the second moment, the steering wheel angle of the electric vehicle 01 is less than the angle threshold.

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

[0053] For ease of understanding, the following Figure 5 , the control method provided in the embodiment of the present application is illustrated by way of example.

[0054] In one embodiment, if Figure 5 As shown, the left wheel of the electric vehicle 01 is the left rear wheel 43, the right wheel of the electric vehicle 01 is the right rear wheel 44, and the electric vehicle 01 deviates to the left. For the convenience of description, the drive motor used to drive the left rear wheel of the electric vehicle 01 is referred to as the left rear wheel drive motor, and the drive motor used to drive the right rear wheel of the electric vehicle 01 is referred to as the right rear wheel drive motor.

[0055] At the first moment, 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, the left rear wheel drive motor is controlled to output drive torque M to the left rear wheel 43 of the electric vehicle 01. l , controls the right rear wheel drive motor to output a drive torque M to the right rear wheel 44 of the electric vehicle 01 r At this time, the driving torque M output by the left rear wheel drive motor l The driving torque M output by the right rear wheel drive motor r The difference between them is small.

[0056] At the second moment after the first moment, if Figure 5 As shown, the controller controls the driving torque M output by the left rear wheel drive motor l The driving torque M output by the right rear wheel drive motor r For example, taking the electric vehicle 01 as an example of deviating to the left, the controller controls the driving torque M output by the left rear wheel drive motor l Increase ΔM l_mot The controller also controls the driving torque M output by the right rear wheel drive motor r Reduce ΔM r_mot , at this time M l With M r The difference between them increases by ΔM r_mot +ΔM l_mot In this way, when the torque difference between the output of the left rear wheel drive motor and the right rear wheel drive motor is large, the driving force received by the left rear wheel 43 and the right rear wheel 44 will be greatly different (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 travel, due to the inconsistency of the driving forces of the two rear wheels, an expected deviation will occur. The expected deviation can offset the deviation of the electric vehicle 01, and finally the purpose of suppressing the deviation of the electric vehicle 01 is achieved, thereby improving the driving safety of the electric vehicle 01.

[0057] In one embodiment, 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.

[0058] The vehicle speed can indicate the current driving state of the electric vehicle 01 and is used to determine whether the electric vehicle 01 is currently in a high-speed driving state. The heading angle offset refers to the angle difference between the heading angle and the expected heading angle of the electric vehicle during straight driving. The lateral offset refers to the lateral distance that the electric vehicle deviates to the left or to the right during straight driving.

[0059] The above-mentioned preset vehicle speed, first preset lateral offset and preset heading angle offset are the trigger thresholds for the function of suppressing the electric vehicle from running off the track. When the speed of the electric vehicle 01 is greater than the preset vehicle speed, it means 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 means that the electric vehicle 01 has deviated during high-speed straight driving and the offset is large, and the electric vehicle 01 needs to be suppressed from running off the track. 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 electric vehicle 01 from running off the track.

[0060] In one embodiment, the lateral offset and the heading angle offset can be calculated by the speed and yaw rate of the electric vehicle. The yaw rate is the angular velocity of the electric vehicle rotating perpendicular to the plane of motion. The yaw rate can be detected by the yaw rate sensor of the electric vehicle. The vehicle speed can be detected by the 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 acquired yaw rate and vehicle speed, thereby determining the yaw control torque required to suppress the electric vehicle from running off the track according to the lateral offset and the heading angle offset, and distribute the yaw control torque to the drive motor of the left wheel and the drive motor of the right wheel to suppress the electric vehicle from running off the track.

[0061] The following is still Figure 5 As an example, the offset direction shown in Figure 6 and Figure 7 , describing in detail the control process of calculating the heading angle offset θ and the lateral offset l, and suppressing the electric vehicle 01 from running off the track.

[0062] In one embodiment, if Figure 6 As shown, when the electric vehicle 01 is traveling in a straight line (the user does not turn the steering wheel, that is, the steering wheel angle is less than the angle threshold), the yaw rate γ of the electric vehicle 01 can be obtained through the yaw rate sensor signal, and the vehicle speed v of the electric vehicle 01 can be obtained through the vehicle speed sensor 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 can calculate 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. These two offsets can be obtained by the following formulas (1) and (2).

[0063]

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

[0065] In one embodiment, if Figure 6 As shown, after calculating the lateral offset l and the 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 the heading angle offset θ. Zt , and based on the yaw control torque M Zt , actively adjusting the difference between the driving torque of the left wheel and the driving torque of the right wheel to increase.

[0066] Where, as mentioned above, the yaw control torque M Zt is the total control torque used to correct the heading angle deviation θ and the lateral deviation l. Zθ It represents the control torque to correct the heading angle deviation θ, expressed as M Zl represents the control torque to correct the lateral offset l, then M Zt =M Zθ +M Zl .

[0067] In a possible implementation, the control torque M Zθ and control torque M Zl It can be calculated by a proportional integration differentiation (PID) closed-loop controller. The PID closed-loop controller can be deployed in the controller. After determining the heading angle offset θ and the lateral offset l, the controller can input the heading angle offset θ and the lateral offset l as error amounts into the PID closed-loop controller to obtain the control torque M required to correct each offset. Zθ and M Zl , the control torque M Zθ and M Zl By adding them together, we can determine the yaw control moment M Zt .

[0068] In one embodiment, if Figure 7 As shown, the controller obtains the yaw control torque M Zt After that, the yaw control moment M Zt The tire force increment ΔF is converted into the tire force increment ΔF, and the tire force increment ΔF is further converted into the change in the driving torque of the left wheel and the driving torque of the right wheel ΔM mot , tire force increment ΔF and driving torque change ΔM motIt can be obtained by the following formulas (3) and (4) respectively. Wherein, the tire force represents the friction between the left wheel and the right wheel and the ground under the action of the driving torque. In the embodiment of the present application, the left wheel is the left rear wheel 43 and the right wheel is the right rear wheel 44 as an example for explanation.

[0069]

[0070] In formula (3), ΔF l represents the tire force increment of the left rear wheel 43, represents the yaw torque distribution factor of 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, ΔF r represents the tire force increment of the right rear wheel 44. In equation (4), ΔM l_mot represents the change in the driving torque of the left rear wheel 43, r l represents the tire radius of the left rear wheel 43, ΔM r_mot represents the change in the driving torque of the right rear wheel 44, r r Indicates the tire radius of the right rear wheel 44.

[0071] In one embodiment, if Figure 6 As shown, the controller determines the change in the driving torque of the left rear wheel 43 ΔM l_mot and the change in the driving torque of the right rear wheel 44 ΔM r_mot Afterwards, a motor torque control signal is output to the motor controller of the left rear wheel drive motor and the motor controller of the right rear wheel drive motor, so as to increase the difference between the driving torques output by the left rear wheel drive motor and the right rear wheel drive motor respectively through the two motor controllers. Then, the driving torque output by the left rear wheel drive motor at the second moment 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 formula (5), M l_act represents the driving torque output by the left rear wheel drive motor at the second moment, M l represents the driving torque output by the left rear wheel drive motor at the first moment. In formula (6), M r_act represents the driving torque output by the right rear wheel drive motor at the second moment, M r The driving torque output at the second moment is based on the driving torque output at the first moment, and the driving torque is 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 Shown in the offset direction of the electric vehicle 01, still taking the left rear wheel 43 and the right rear wheel 44 as an example. Combining the above formulas (1) to (6), it can be seen that when the lateral offset l is larger, the corresponding yaw control moment M Zt is larger. According to this yaw control moment 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, 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 shown, at the second moment, the lateral offset l to the left of the electric vehicle 01 is greater than the first preset lateral offset, indicating that the electric vehicle 01 is currently offset to the left and the offset is large, and the controller can actively adjust the driving torque of the left wheel to be greater than the driving torque of the right 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 that the electric vehicle 01 continues to move to the right as expected, thereby achieving the purpose of suppressing the deviation of the electric vehicle 01. 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 only actively increases the driving torque of the left rear wheel 43, or the controller only actively reduces the driving torque of the right rear wheel 44, and the embodiment of the present application does not make specific limitations on this.

[0078] Figure 5 This is a schematic diagram of the electric vehicle 01 veering to the left. The control process of the electric vehicle 01 veering to the right is similar to this and will not be repeated here.

[0079] In one embodiment, the control method provided in the present application specifically includes: at a second moment, the lateral offset to the left of the electric vehicle is greater than a 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 a second moment, 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 adjusted to increase and the driving torque of the left wheel is adjusted to decrease.

[0080] Combination Figure 5 In the offset direction of the electric vehicle 01 shown in FIG. 1 , at the second moment, the lateral offset l of the electric vehicle 01 to the left is greater than the first preset lateral offset, and the controller actively adjusts the driving torque of the left rear wheel 43 to increase, and adjusts the driving torque of the right rear wheel 44 to decrease. For example, the controller actively adjusts the driving torque M output by the left rear wheel driving motor to l Increase ΔM l_mot , and actively adjusts the driving torque M output by the right rear wheel drive motor r Reduce ΔM r_mot The adjusted driving torque output by the left rear wheel drive motor is M l_act =M l +ΔM l_mot The adjusted driving torque output by the right rear wheel drive motor is M r_act =M r -ΔM r_mot The control process of the electric vehicle 01 running to the right is similar to this and will not be described in detail here.

[0081] In one embodiment, the control method provided in the present application specifically includes: at a second moment, the lateral offset to the left of the electric vehicle is greater than a 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 a second moment, the lateral offset to the right of the electric vehicle is greater than the first preset lateral offset, and 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.

[0082] Combination Figure 5 As can be seen from the above equations (3) and (4), without considering special road conditions, when the electric vehicle 01 deviates 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. The value of is 0.5, that is, the tire force increment ΔF is evenly distributed to the left rear wheel and the right rear wheel. The tire force increment ΔF of the left rear wheel 43 is l The tire force increment ΔF of the right rear wheel 44 r The radius r of the tire of the left rear wheel 43 is equal to l The radius r of the tire of the right rear wheel 44 r equal, the increase value ΔM of the driving torque of the left rear wheel 43 l_mot With ΔM r_mot The reduction value of the driving torque of the right rear wheel 44 is equal. The control process of the electric vehicle 01 running to the right is similar to this, and will not be repeated here.

[0083] The following is still Figure 5 For example, combined with Figure 8 and Fig. 9 , respectively describing the adjustment process of the driving torque of the left wheel and the driving torque of the right wheel of the 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 the present application specifically includes: at a second moment, the left 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, and the increase in the driving torque of the left wheel is adjusted to be less than the decrease in the driving torque of the right wheel; at a second moment, the left 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, and the increase in the driving torque of the left wheel is adjusted to be greater than the decrease in the driving torque of the right wheel.

[0085] like Figure 8 As shown, when the electric vehicle is on a side slope road, the slope θ bThis will cause the center of mass position of the electric vehicle 01 to shift, causing the vertical load acting on the wheels of the electric vehicle 01 to change. The greater the vertical load, the greater the driving force required for the wheel to travel, the greater the torque threshold of the drive motor that drives the wheel, and the greater the output torque of the drive motor that drives the wheel. The torque threshold is the torque range when the drive motor is working normally. When the driving torque output by the drive motor exceeds the torque threshold, the motor controller of the electric vehicle will adjust the driving torque output by the drive motor to avoid overload or damage, thereby ensuring driving safety.

[0086] Combination Figure 5 The offset direction of the electric vehicle 01 shown, when the electric vehicle 01 is driving on a side slope road surface, takes the left rear wheel 43 and the right rear wheel 44 as an example. If the height of the left rear wheel 43 is greater than the height of the right rear wheel 44, it means that the left rear wheel 43 of the electric vehicle 01 is currently on the slope, while the right rear wheel 44 is below the slope. The center of mass position 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, resulting in a decrease in the dynamic radius of the right rear wheel 44, that is, the tire radius r of the right rear wheel 44. r The tire force increment ΔF of the right rear wheel 44 will be temporarily reduced. r From the above formula (4), it can be seen that the change in the driving torque of the right rear wheel 44 is ΔM r_mot The driving torque of the left rear wheel 43 changes accordingly. l_mot will decrease accordingly, that is, ΔM r_mot >ΔM 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 means that the left rear wheel 43 of the electric vehicle 01 is currently below the slope, while the right rear wheel 44 is above the slope. The center of mass of the electric vehicle 01 will move toward the side of the electric vehicle 01 below the slope, increasing the vertical load of the left rear wheel 43 and reducing the dynamic radius of the left rear wheel 43, that is, the tire radius r of the left rear wheel 43. l will temporarily decrease, and the tire force increment ΔF of the left rear wheel 43 l From the above formula (4), it can be seen that the change in the driving torque of the left rear wheel 43 is ΔM l_mot The driving torque of the right rear wheel 44 changes accordingly. r_mot will decrease accordingly, that is, ΔM r_mot <ΔM l_mot .

[0088] The control process of the electric vehicle 01 running to the right is similar to this and will not be repeated here.

[0089] In one embodiment, when the adhesion coefficients between the left wheel and the right wheel of the electric vehicle and the road surface are different, the control method provided in the present application specifically includes: at a second moment, the left 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, and the increase value of the driving torque of the left wheel is adjusted to be greater than the decrease value of the driving torque of the right wheel; at a second moment, the left 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, and the increase value of the driving torque of the left wheel is adjusted to be less than the decrease value of the driving torque of the right wheel.

[0090] like Fig. 9 As shown in the figure, on the split road, the adhesion coefficient between the wheel and the road will cause the tire force boundary of the wheel to change, making the yaw torque distribution factor The split road surface refers to a road surface with different adhesion coefficients on both sides, one side of the road surface has a higher adhesion coefficient, and the other side of the road surface has a lower adhesion coefficient.

[0091] Combination Figure 5 The offset direction of the electric vehicle 01 shown, when the electric vehicle 01 travels to the open road, takes the left rear wheel 43 and the right rear wheel 44 as an example. If the adhesion coefficient between the left rear wheel 43 and the road is greater than the adhesion coefficient between the right rear wheel 44 and the road, it means that more power needs to be distributed to the tire on the side with a higher adhesion coefficient, that is, to the left rear wheel 43. In a possible implementation, the adhesion coefficient can be obtained by the electric vehicle sensor of the electric vehicle 01. The electric vehicle sensor can obtain the adhesion coefficient μ between the left rear wheel 43 and the road. l and the adhesion coefficient μ between the right rear wheel 44 and the road surface r The controller is based on the received adhesion coefficient μ l and μ r , when calculating the tire force increments of the two rear wheels, adjust the yaw torque distribution factor of the left rear wheel 43 The value of is greater than 0.5, so that the yaw torque distribution factor of the right rear wheel 44 The value of is less than 0.5, so that the larger tire force increment is allocated to the left rear wheel 43, and the smaller tire force increment is allocated to the right rear wheel 44. Then, according to the tire force increment, 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 driving torque variation of the left rear wheel drive motor and the driving torque variation of the right rear wheel drive motor, the increase value of the driving torque of the left rear wheel is adjusted to be greater than the decrease value of the driving torque of the right rear wheel, that is, ΔM l_mot >ΔM r_motSimilarly, when the adhesion coefficient between the left rear wheel 43 and the road surface is smaller than the adhesion coefficient between the right rear wheel 44 and the road surface, the increase in the driving torque of the left rear wheel is adjusted to be smaller than the decrease in the driving torque of the right rear wheel, that is, ΔM l_mot <ΔM r_mot .

[0092] The control process of the electric vehicle 01 running to the right is similar to this and will not be repeated here.

[0093] In one embodiment, the control method provided by the present application further includes: at a third moment after the second moment, adjusting the difference between the driving torque of the left wheel and the driving torque of the right wheel to decrease. In a possible implementation, at the third moment, the controller can detect that the lateral offset and the heading angle offset of the electric vehicle 01 are reduced to a 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 01 to gradually decrease, so that the driving torque of the left wheel and the driving torque of the right wheel are restored to a balanced state, and in the subsequent driving of the electric vehicle 01, the driving needs of the user's operation are promptly responded to.

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

[0095] Among them, the steering wheel angle is greater than the angle threshold, which means that the user has operated the steering wheel and hopes to control the electric vehicle 01 to turn or end the straight-ahead state. The opening of the brake pedal is greater than the preset brake pedal opening, which means that the user has stepped on the brake pedal and hopes to control the electric vehicle 01 to reduce its speed or stop. The controller will gradually reduce the yaw control torque to end the deviation suppression of the electric vehicle 01. In one example, at the third moment, after the controller detects that the steering wheel angle is greater than the angle threshold or the opening of the brake pedal is greater than the preset brake pedal opening, it sends an exit signal to the motor controller of the left wheel and the motor controller of the right wheel. After receiving the exit signal, the motor controller of the left wheel and the motor controller of the right wheel control the difference between the driving torque of the left wheel and the driving torque of the right wheel to decrease.

[0096] In one embodiment, the control method provided in the present application specifically includes: at a second moment, adjusting the difference between the driving torque of the left wheel and the driving torque of the right wheel to increase at a first rate; at a third moment, adjusting the difference between the driving torque of the left wheel and the driving torque of the right wheel to decrease at a second rate that is less than the first rate.

[0097] Combination Figure 5As shown in the offset direction of the electric vehicle 01, at the second moment, the controller first 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 moment, 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, thereby ensuring that the driving torque of the left rear wheel 43 and the driving torque of the right rear wheel 44 can return to a balanced state at a relatively gentle rate, avoiding the sense of frustration caused by too rapid increase or decrease in the driving torque, and improving the user's driving experience.

[0098] In one embodiment, the control method provided in the present application specifically includes: when the electric vehicle is traveling at a first speed, at the moment 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 adjusted to be reduced. At this time, the moment when the steering wheel angle is greater than the first angle threshold is the above-mentioned third moment; when the electric vehicle is traveling at a second speed, at the moment when the steering wheel angle of the electric vehicle is greater than the second angle threshold, the difference between the driving torque of the left wheel and the driving torque of the right wheel is adjusted to be reduced. At this time, the moment when the steering wheel angle is greater than the second angle threshold is the above-mentioned third moment; the first vehicle speed is less than the second vehicle speed, and the first angle threshold is greater than the second angle threshold.

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

[0100] In one embodiment, the control method provided by the present application also includes: at the second moment, the lateral offset of the electric vehicle is greater than the second preset lateral offset, and an alarm signal is output to the user. In a possible implementation, at the second moment, the controller can calculate and evaluate the heading angle offset and the lateral offset in real time during the process of suppressing the deviation of the electric vehicle 01, and output the calculated heading angle offset and lateral offset to the vehicle display screen or external device, so that the user can promptly know the deviation suppression status of the electric vehicle 01. If at the second moment, the lateral offset of the electric vehicle 01 exceeds the second preset lateral offset, it means that in the process of suppressing the deviation of the electric vehicle 01, the lateral offset of the electric vehicle 01 has not decreased as expected, or the lateral offset of the electric vehicle 01 is still increasing, and it is necessary to send an alarm signal to the user in time to remind the user to pay attention to the current offset status of the electric vehicle 01.

[0101] Combine the following Fig.10 The specific embodiment also describes in detail the process of suppressing the deviation of the electric vehicle. Still taking the electric vehicle 01 deviating to the left as an example.

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

[0103] From time t1 to time t2 (second time), it is still the straight driving stage. From time t1 to time t2, the electric vehicle is driving straight, the user does not turn the steering wheel or the steering wheel angle is less than the angle threshold R1, and the user does not step on the brake pedal or the brake pedal opening is less than the preset brake pedal opening L1, the driving torque M of the left rear wheel l_act =M l And the driving torque of the right rear wheel M r_act =M r That is to say, before time t2, the electric vehicle was in the process of going straight and deviating.

[0104] From time t2 (second time) to time t4 (third time) is the stage of adjusting the driving torque. From time t2 to time t3, the driving torque of the left rear wheel increases by ΔM l_mot , the driving torque of the right rear wheel is reduced by ΔM r_mot At time t3, the driving torque M of the left rear wheel l_act =M l +ΔM l_mot， The driving torque of the right rear wheel is Mr_act =M r -ΔM r_mot From time t3 to time 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 deviates as expected, thereby offsetting the deviation of the electric vehicle, thereby achieving the purpose of correcting the deviation of the electric vehicle. In other words, from time t2 to time t4 is the process of suppressing the deviation of the electric vehicle.

[0105] From time t4 (the third time) to time t5, the electric vehicle 01 stops the deviation control process. At time t4, the user turns 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, and the electric vehicle 01 exits the deviation control process, and the driving torque M of the left rear wheel is l_act Gradually decrease to M l , the driving torque of the right rear wheel M r_act Gradually decrease to M r That is to say, from time t4 to time t5, the electric vehicle 01 exits the process of suppressing deviation. After time t5, the electric vehicle 01 responds normally to the user's driving operation.

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

[0107] When the electric vehicle is moving straight, 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 function. If the deviation suppression function needs to be started, the controller activates the deviation suppression function and calculates the deviation posture of the electric vehicle based on the input signal, that is, calculates the heading angle deviation and the lateral deviation.

[0108] If the heading angle offset is greater than the preset heading angle offset, or the lateral offset is greater than the first preset lateral offset, the required yaw control torque is calculated by the heading angle offset PID controller and the lateral offset PID controller respectively. The controller performs differential distribution of the driving torque according to the calculated yaw control torque, and controls the corresponding driving motor output torque through the motor controller.

[0109] An embodiment of the present application also provides a controller for an electric vehicle, which is used to execute the control method for suppressing the electric vehicle from running off track provided in the above embodiment.

[0110] An embodiment of the present application also provides an electric vehicle, which includes two left wheels, two right wheels and a distributed power assembly, wherein the distributed power assembly includes two drive motors and a controller, wherein the controller is used to control one drive motor to drive a left wheel and to control another drive motor to drive a right wheel coaxial with a left wheel; the controller is used to control the electric vehicle to suppress deviation after the electric vehicle deviates during straight-line driving, and the controller is specifically used to: when the electric vehicle is driving at a speed greater than a preset speed, in response to a lateral offset of the electric vehicle being greater than a first preset lateral offset, control the difference in torque output by the two drive motors to increase.

[0111] Finally, it should be noted that the above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A control method for suppressing deviation of an electric vehicle, characterized in that: The control method is used to control the electric vehicle to prevent deviation after the electric vehicle deviates during straight-line driving, and the control method includes: At a first moment, controlling the driving system to output driving torque to the left wheel and the right wheel of the electric vehicle; At a second moment after the first moment, adjusting the difference between the driving torque of the left wheel and the driving torque of the right wheel to increase; Among them, at the first moment and the second moment, the steering wheel angle of the electric vehicle is less than the angle threshold.

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 a 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 rightward lateral offset of the electric vehicle is greater than a 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, the leftward lateral offset of the electric vehicle 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 moment, the rightward lateral offset of the electric vehicle is greater than a first preset lateral offset, and the driving torque of the right wheel is adjusted to increase and the driving torque of the left wheel is adjusted to decrease.

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 value of the driving torque of the left wheel is adjusted to be equal to the decrease value of the driving torque of the right wheel; At the second moment, the rightward lateral offset of the electric vehicle is greater than a first preset lateral offset, and the increase value of the driving torque of the right wheel is adjusted to be equal to the decrease value of 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, and the increase value of the driving torque of the left wheel is adjusted to be less than the decrease value of the driving torque of the right wheel; At the second moment, the left 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, and the increase in the driving torque of the left wheel is adjusted to be greater than the decrease in the driving torque of the right wheel.

7. 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 adhesion coefficient between the left wheel and the road surface is greater than the adhesion coefficient between the right wheel and the road surface, and the increase value of the driving torque of the left wheel is adjusted to be greater than the decrease value of the driving torque of the right wheel; At the second moment, the left 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 smaller than the adhesion coefficient between the right wheel and the road surface, and the increase value of the driving torque of the left wheel is adjusted to be smaller than the decrease value of the driving torque of the right wheel.

8. 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 greater than the first preset lateral offset, adjusting the difference between the driving torque of the left wheel and the driving torque of the right wheel to increase 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 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 adjusted to increase to a second difference after the second moment, and the second difference is greater than the first difference.

9. The control method according to claim 1, characterized in that: The control method further comprises: At a third time after the second time, the difference between the driving torque of the left wheel and the driving torque of the right wheel is adjusted to decrease.

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

11. The control method according to claim 9, characterized in that: The control method specifically includes: At the second moment, adjusting the difference between the driving torque of the left wheel and the driving torque of the right wheel to increase at a 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 adjusted to decrease at a second rate that is smaller than the first rate.

12. The control method according to claim 9, characterized in that: The control method specifically includes: During the driving process of the electric vehicle at a first speed, at a moment when the steering wheel angle of the electric vehicle is greater than a first angle threshold, adjusting the difference between the driving torque of the left wheel and the driving torque of the right wheel to be reduced, wherein the moment when the steering wheel angle is greater than the first angle threshold is the third moment; During the driving process of the electric vehicle at the second speed, at the moment when the steering wheel angle of the electric vehicle is greater than the second angle threshold, the third moment adjusts the difference between the driving torque of the left wheel and the driving torque of the right wheel to be reduced, wherein the moment when the steering wheel angle is greater than the second angle threshold is the third moment; The first vehicle speed is lower than the second vehicle speed, and the first turning angle threshold is higher than the second turning angle threshold.

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

14. A controller for an electric vehicle, characterized in that: The controller is used to execute the method according to any one of claims 1 to 13.

15. An electric vehicle, characterized in that: The electric vehicle comprises two left wheels, two right wheels and a distributed powertrain, wherein the distributed powertrain comprises two drive motors and a controller, wherein the controller is used to control one of the drive motors to drive a left wheel and to control another of the drive motors to drive a right wheel coaxial with the left wheel; The controller is used to control the electric vehicle to prevent deviation after the electric vehicle deviates during straight-line driving. The controller is specifically used to: During the driving process of the electric vehicle at a speed greater than a preset speed, in response to a lateral offset of the electric vehicle being greater than a first preset lateral offset, the difference in torque output by the two driving motors is controlled to increase.

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