Vehicle steering control method, device and system, vehicle and storage medium

Abstract

The invention provides a steering control method, device and system of a vehicle, the vehicle and a storage medium, and the method comprises the steps that when a crabbing function is activated, two rear wheels and a front wheel of the vehicle are controlled to steer in the same direction, and differential torque control is conducted on the two rear wheels of the vehicle, so that the vehicle moves in a crabbing mode. Two rear wheels and a front wheel of the vehicle are controlled to steer in the same direction, differential torque control is conducted on the two rear wheels of the vehicle, so that the difference between the steering angle of a front axle and the steering angle of a rear axle is made up based on the differential torque control, the vehicle moves in a crabbing mode, and crabbing obstacle avoidance of a larger angle is achieved.

Description

Technical Field

[0001] The present invention relates to the field of vehicle technology, and in particular to a vehicle steering control method, device, system, vehicle and storage medium. Background Art

[0002] The traditional steering function is mainly achieved by the driver controlling the steering angle of the front wheels by operating the steering wheel. When facing narrow spaces or complex environments, the turning radius of the above-mentioned steering method is large, which may make it difficult for the driver to pass through narrow curved areas or bypass obstacles in one go.

[0003] In order to improve the maneuverability and flexibility of vehicles in narrow spaces, vehicle assisted steering technologies are proposed, such as tank U-turns and U8 agile steering. For example, when the front and rear wheels of the vehicle are turned in the same direction, the opposite driving torques applied to the front and rear wheels are configured so that the driving forces applied to the front and rear wheels on the same side of the vehicle body are equal in magnitude and opposite in direction in the longitudinal direction of the vehicle, and the stationary vehicle can rotate roughly around the center of mass of the vehicle without obvious displacement in the longitudinal direction, thereby reducing the turning radius of the vehicle. However, the aforementioned method of rotating the vehicle around the center of the vehicle causes obvious abrupt setbacks during the overall driving of the vehicle, and cannot achieve rapid turning or obstacle avoidance in narrow urban spaces. That is, after the vehicle enters the turning state, although the current vehicle assisted steering can help reduce the turning radius of the vehicle, it is inevitable that the vehicle cannot pass through in some narrow spaces, and there is a possibility that the vehicle is in danger. Summary of the invention

[0004] In view of the above problems, embodiments of the present invention are proposed to provide a vehicle steering control method, a corresponding control device, a corresponding electric drive system, a corresponding vehicle and a corresponding computer-readable storage medium that overcome the above problems or at least partially solve the above problems.

[0005] An embodiment of the present invention discloses a vehicle steering control method, the method comprising:

[0006] When the crab walking function is activated, the two rear wheels of the vehicle are controlled to steer in the same direction as the front wheels, and the two rear wheels of the vehicle are subjected to differential torque control so as to make the vehicle move in a crab walking manner.

[0007] Optionally, the method further includes:

[0008] The two rear wheels of the vehicle are controlled to steer to a target steering angle, where the target steering angle is suitable for being set to any value between zero degrees and a steering threshold.

[0009] Optionally, the target steering angle is the steering threshold of the rear wheels.

[0010] Optionally, the step of performing differential torque control on the two rear wheels of the vehicle includes:

[0011] The two rear wheels of the vehicle are subjected to differential torque control according to the difference between the front wheel steering angle and the rear wheel steering angle, and the rear axle differential torque, so as to make the vehicle perform crab motion.

[0012] Optionally, the step of performing differential torque control on the two rear wheels of the vehicle according to the difference between the front wheel steering angle and the rear wheel steering angle and the rear axle differential torque to make the vehicle crab move comprises:

[0013] Determine the required torque of the rear axle according to the difference between the front wheel steering angle and the rear wheel steering angle;

[0014] The two rear wheels of the vehicle are subjected to differential torque control according to the rear axle required torque and the rear axle differential torque, so as to enable the vehicle to perform crab motion.

[0015] Optionally, the front wheel steering angle is directly proportional to the steering wheel angle.

[0016] Optionally, the rear axle differential torque includes a rear axle basic differential torque, and the rear axle basic differential torque is determined according to a preset corresponding relationship between a steering wheel angle and a steering wheel torque.

[0017] Optionally, the rear axle differential torque also includes a correction coefficient, the rear axle differential torque = the rear axle basic differential torque * the correction coefficient, the correction coefficient includes one of the braking attenuation coefficient, the rear wheel torque coefficient and the slope attenuation coefficient and a combination thereof, and the numerical signs of the differential torques of the two wheels are different.

[0018] Optionally, the rear axle differential torque also includes a correction coefficient and a direction indication value, the rear axle differential torque = the direction indication value * the rear axle basic differential torque * the correction coefficient, the correction coefficient includes one of the braking attenuation coefficient, the rear wheel torque coefficient and the slope attenuation coefficient and a combination thereof, when the turning direction of the vehicle is left, the direction indication value is a positive value, and when the turning direction of the vehicle is right, the direction indication value is a negative value.

[0019] Optionally, the braking attenuation coefficient is negatively correlated with the braking depth.

[0020] Optionally, the slope attenuation coefficient is negatively correlated with the slope.

[0021] Optionally, the step of performing differential torque control on the two rear wheels of the vehicle to make the vehicle crab move includes:

[0022] When it is determined based on the vehicle driving information and the vehicle environment information that the vehicle meets a preset activation condition, the crab motion function is activated to perform differential torque control on the two rear wheels of the vehicle so as to enable the vehicle to crab motion;

[0023] When it is determined based on the vehicle driving information and the vehicle environment information that the vehicle does not meet the preset activation condition, the crab steering function is not activated.

[0024] Optionally, the vehicle driving information includes front wheel steering angle information, gear position information and braking depth information, and the vehicle environment information includes slope information;

[0025] The preset activation conditions include: the front wheel steering angle information does not exceed the preset angle threshold, the slope information does not exceed the preset slope threshold, the braking depth information does not exceed the preset depth threshold and the gear information meets the preset driving information, wherein the preset driving information includes preset traveling information and preset reversing information.

[0026] Optionally, the method further includes:

[0027] The vehicle is subjected to torque zero-crossing smoothing control according to the current vehicle speed and road adhesion coefficient of the vehicle.

[0028] Optionally, performing torque zero-crossing smooth control on the vehicle according to the current vehicle speed and road adhesion coefficient of the vehicle includes:

[0029] Determining the actual wheel end torque according to the current vehicle speed and the road adhesion coefficient of the vehicle;

[0030] Based on the torque range of the actual wheel end torque, the torque variation amplitude when the crab function target torque is output is controlled.

[0031] Optionally, the method further includes:

[0032] The target torque of the crab function is limited according to the road adhesion coefficient.

[0033] Optionally, limiting the crab function target torque according to the road adhesion coefficient includes:

[0034] When it is determined based on the road adhesion coefficient that the rear wheel is slipping, limiting the rear wheel end target torque based on the rear wheel drive motor torque;

[0035] When it is determined based on the road adhesion coefficient that the rear wheels are not slipping, the rear wheel end target torque is limited based on the rear wheel drive motor torque and the rear wheel torque limit.

[0036] Optionally, the method further includes:

[0037] The current driving trajectory of the vehicle is revised according to the yaw rate.

[0038] Optionally, the method further includes:

[0039] The output displays the revised driving trajectory to assist the vehicle owner in driving.

[0040] An embodiment of the present invention further discloses a control device, which includes a controller component, a memory, and a computer program stored in the memory. When the computer program is executed by the controller component, any one of the vehicle steering control methods is implemented.

[0041] Optionally, the controller component includes a vehicle controller, a vehicle motion controller and a motor control unit.

[0042] Optionally, the vehicle controller performs a fault judgment on the crab function and sends a crab function fault instruction to the vehicle motion controller; the vehicle motion controller performs a fault judgment on the crab function again based on the crab function fault instruction.

[0043] Optionally, the vehicle motion controller sends a crab function activation instruction to the vehicle controller, and the vehicle controller makes a crab function activation judgment based on the crab function activation instruction.

[0044] Optionally, the controller component further comprises a display, and the display is used to respond to a crab crawl function activation instruction and display a driving trajectory of the vehicle during crab crawling.

[0045] The embodiment of the present invention further discloses an electric drive system, the electric drive system comprising:

[0046] A motor at the front end is used to output torque to the two front wheels of the vehicle; two motors at the rear end are used to output torque to the two rear wheels of the vehicle respectively; and any one of the control devices. The embodiment of the present invention also discloses a vehicle, including: any one of the control devices; or any one of the electric drive systems.

[0047] The embodiment of the present invention further discloses a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the computer program implements any of the vehicle steering control methods.

[0048] The embodiments of the present invention include the following advantages:

[0049] In the embodiment of the present invention, when the crab steering function is activated, the two rear wheels of the vehicle can be controlled to steer in the same direction as the front wheels, and the two rear wheels of the vehicle can be subjected to differential torque control, so as to make up for the difference between the steering angle of the front axle and the steering angle of the rear axle based on the differential torque control, so that the vehicle can crab-steering and achieve a larger angle of crab-steering obstacle avoidance, thereby helping to reduce the turning radius of the vehicle and achieve the purpose of rapid steering or obstacle avoidance in narrow urban spaces. Furthermore, the differential torque control of the two rear wheels of the vehicle can be intervened to achieve point-to-point oblique motion with almost no yaw, thereby increasing the stability of the vehicle during the crab steering process. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a structural schematic diagram of a control device of the present invention;

[0051] Figure 2 is a schematic diagram of the functional architecture of each controller component in a control device provided by an embodiment of the present invention;

[0052] Figure 3 is a flowchart of a vehicle steering control method embodiment of the present invention;

[0053] Figure 4 is a schematic diagram of vehicle steering provided by an embodiment of the present invention;

[0054] Figure 5 It is a structural block diagram of an electric drive system embodiment of the present invention. DETAILED DESCRIPTION

[0055] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0056] The vehicle's crab walk function, when activated, allows the vehicle to move sideways, achieving crab walk.

[0057] Reference Figure 1 , showing a schematic diagram of the structure of a control device of the present invention, the control device may include a controller component, a memory and a computer program stored in the memory, and the computer program can be executed by the controller component to implement the vehicle steering control method proposed in an embodiment of the present invention.

[0058] like Figure 1As shown, the controller components may include a vehicle controller 10 (Vehicle Control Unit, VCU for short), a display 11, a motor control unit 12 (Microcontroller Unit, MCU for short), a vehicle motion controller Didyna 13, an intelligent integrated braking control system 14 (Integrated Power Brake, IPB for short), a steering control system 15 (Electric Power Steering, EPS for short), a rear wheel steering system 16 (Rear Wheel Steering, RWS for short), an active suspension system Disus 17, and an electronic parking system 18 (Electric Park Brake, EPB for short).

[0059] Specifically, the controller component can perform a double fault judgment when the crab walking function is turned on, and perform a double activation process after determining that there is no fault and turning on the crab walking function.

[0060] The double fault judgment can be mainly manifested in that the fault judgment of the crab crawling function is performed by the vehicle controller 10, and a crab crawling function fault instruction is sent to the vehicle motion controller 13, and then the vehicle motion controller 13 performs the crab crawling function fault judgment again based on the crab crawling function fault instruction, so as to ensure the safety of the vehicle when performing the crab crawling motion based on the double fault judgment.

[0061] The dual activation processing can be mainly manifested in sending a crab crawling function activation instruction to the vehicle controller 10 through the vehicle motion controller 13, and then the vehicle controller 10 makes a crab crawling function activation judgment based on the crab crawling function activation instruction, so as to further ensure the safety of the vehicle when performing crab crawling based on the dual activation processing.

[0062] Optionally, the display in the controller assembly can also be used to respond to the crab walking function activation command to display the driving trajectory of the vehicle during the crab walking movement, further ensuring the safety of the vehicle during the crab walking movement. Exemplarily, the display 11 can be a panoramic assist display (Panoramic Assist Display, referred to as PAD).

[0063] Specifically, the functional architecture of each controller component in the control device can be as follows: Figure 2As shown, when the user turns on the crab walking function through the PAD switch, that is, when the driver manually turns on the crab walking function through the PAD, the PAD can synchronize the driver's crab walking function requirements to the vehicle controller VCU and the vehicle motion controller Didyna, and send a configuration switch signal to the vehicle controller VCU and the vehicle motion controller Didyna. The vehicle controller VCU and the vehicle motion controller Didyna can receive the crab walking function start instruction; the vehicle controller VCU can perform a crab walking function fault judgment, and after performing the crab walking function fault judgment, a crab walking function fault alarm can be generated based on the current crab walking function fault judgment result. Instructions are sent, and a crab walking function fault instruction is sent to the vehicle motion controller Didyna, so that the vehicle motion controller Didyna can respond to the crab walking function fault instruction and perform crab walking function fault judgment again, which is specifically manifested in obtaining vehicle fault information, analyzing the crab walking function fault judgment result performed by the aforementioned vehicle controller VCU, and when it is determined that the fault state of the crab walking function is no fault, the vehicle motion controller Didyna can send a crab walking function start signal to the vehicle controller VCU, so that the vehicle controller VCU responds to turn on the crab walking function, thereby realizing double fault judgment when the crab walking function is turned on.

[0064] Optionally, when the vehicle motion controller Didyna detects a vehicle failure or a crab walking function failure, it means that the preset crab walking function activation conditions cannot be met. At this time, feedback can be synchronously sent to the PAD, and a corresponding display can be made in the PAD interface to inform the user that the crab walking function is not available.

[0065] like Figure 2 As shown, after the vehicle motion controller Didyna sends a crab crawling function start signal to the vehicle controller VCU, the vehicle motion controller Didyna can also make a preliminary crab crawling function activation judgment on the vehicle driving information and the vehicle environmental information to determine whether the crab crawling function meets the preset activation conditions. When it is preliminarily determined that the crab crawling function meets the preset activation conditions, a crab crawling function activation instruction is generated, and the crab crawling function activation instruction is sent to the vehicle controller VCU. The vehicle controller VCU can make a crab crawling function activation judgment again based on the crab crawling function activation instruction. For example, it can again determine whether the vehicle meets the preset activation conditions based on the vehicle driving information and the vehicle environmental information. When it is determined that the vehicle meets the preset activation conditions, the crab crawling function is activated to control the vehicle to perform crab crawling based on the crab crawling function.

[0066] In the embodiment of the present invention, when the crab walking function is activated, the two rear wheels of the vehicle can be controlled to steer in the same direction as the front wheels, and the two rear wheels of the vehicle can be differentially controlled to make the vehicle crab-walk.

[0067] Specifically, after the crab walking function is activated, Figure 2As shown, the vehicle motion controller can transmit relevant information of the rear wheel steering angle to the vehicle controller for the vehicle controller to calculate the target torque difference, and then perform torque difference control on the two rear wheels of the vehicle. Specifically, the motor control unit responds to the target speed and target torque to control the two rear wheels accordingly, thereby realizing torque difference control.

[0068] In actual applications, the configuration switch signal can be sent to the vehicle controller VCU and the vehicle motion controller Didyna through the PAD. The vehicle controller VCU can receive the function switch signal sent by the PAD. After the crab function is turned on, the PAD can receive the function switch signal sent by the vehicle motion controller Didyna. The steering control system EPS can send the steering wheel angle signal to the vehicle motion controller Didyna. When the crab function is activated, the VCU can receive the crab function activation signal sent by the vehicle motion controller Didyna. The rear-wheel steering system RWS can send the actual rear wheel angle signal to the vehicle motion controller Didyna, and can receive the target rear wheel angle signal sent by the vehicle motion controller Didyna. The front wheel motor control unit FMCU (Front Microcontroller Unit), the left rear wheel motor control unit RLMCU (RearLeft Motor Control Unit) and the right rear wheel motor control unit RRMCU (Rear Right Motor The vehicle control unit (VCU) can send the actual torque signal to the vehicle controller VCU. At the same time, the vehicle controller VCU can send the throttle depth signal, IMU signal (actual yaw angular velocity and slope judgment), front motor torque, left rear wheel, and right rear wheel actual torque in real time, and calculate the target torque signal based on the above information, and then send the target torque signal to the front / left rear / right rear motor control unit FMCU / RLMCU / RRMCU, so that the front / left rear / right rear motor control unit FMCU / RLMCU / RRMCU can control the actual torque accordingly based on the received target torque signal. In addition, the electronic parking system EPB can mainly receive the vehicle request from the vehicle motion controller Didyna, and at the same time feedback the actual status signal of EPB. It should be noted that the above-mentioned system components usually communicate with each other through the vehicle's CAN (Controller Area Network) bus to achieve efficient data exchange and coordinated control.

[0069] Optional, such as Figure 2As shown, the vehicle controller can perform trajectory calculation, for example, revise the current driving trajectory of the vehicle according to the yaw angular velocity, and then output the revised driving trajectory to the display screen to assist the driver in driving. The display screen can display the revised driving trajectory by popping up a panoramic interface and displaying the vehicle turning trajectory, which is not limited in this embodiment of the present invention.

[0070] Reference Figure 3 , shows a flow chart of steps of a vehicle steering control method embodiment of the present invention, the vehicle steering control method provided by the embodiment of the present invention can be as follows Figure 1 The control device shown is implemented, that is, involving various controller components, and may specifically include the following steps:

[0071] Step S301, when the crab walking function is activated, the two rear wheels of the vehicle are controlled to steer in the same direction as the front wheels, and the two rear wheels of the vehicle are subjected to differential torque control to enable the vehicle to crab walk.

[0072] The crab steering function allows all the wheels of the vehicle to turn in the same direction at the same angle, allowing the vehicle to move almost sideways. This function has the advantages of easy speed control, traceable trajectory, good stability, less body vibration, and acceptable wheel slip and wear. The crab steering function can be applied to all roads, and basic application scenarios can include narrow road scenarios, parking scenarios, etc. For example, the driver frequently turns to avoid obstacles on narrow roads, or parks or exits the garage sideways on narrow roads.

[0073] The crab steering function can control the two rear wheels of the vehicle to steer in the same direction as the front wheels. Specifically, the two rear wheels of the vehicle can be controlled to steer to a target steering angle. The target steering angle is suitable for being set to any value between zero degrees and a steering threshold.

[0074] like Figure 4 As shown, the front wheel steering angle and the rear wheel steering angle can be in a 1:1 ratio. Based on the steering center a, the rear wheel steering angle can be adjusted in real time following the front wheel steering angle, and the rear wheel steering is the same as the front wheel steering.

[0075] In actual applications, when the user turns on the crab steering function through the PAD switch, for example, when the crab steering function requirement is triggered through PAD operation or voice, the user can operate the steering wheel to steer. When the vehicle controller VCU and the vehicle motion controller Didyna determine that there is no fault in the crab steering function, the vehicle motion controller Didyna can control the rear-wheel steering system RWS through the steering control system EPS to control the rear wheels and the front wheels to follow each other.

[0076] The rear-wheel steering system RWS has a limit on the extreme steering angle, that is, the rear-wheel steering angle has a limit on the extreme steering angle during the process of following the front-wheel steering angle. The steering threshold of the rear wheel may refer to the rear-wheel steering angle limit, for example 10°.

[0077] In one embodiment of the present invention, in the process of controlling the two rear wheels of a vehicle to turn in the same direction as the front wheels, when the two rear wheels of the vehicle turn to the steering threshold of the rear wheels, the steering angle of the rear axle will have a certain angle difference from the steering angle of the front axle. At this time, the two rear wheels of the vehicle can be differentially torque controlled by the activated crab steering function, so as to make up for the difference between the steering angle of the front axle and the steering angle of the rear axle based on the differential torque control, thereby achieving crab steering obstacle avoidance with a larger angle.

[0078] Optionally, the differential torque control performed by the crab function depends on the implementation of the crab function.

[0079] First, you can turn on the crab walking function.

[0080] Specifically, the activation of the crab walking function of the vehicle needs to be realized under the condition that the function activation requirements are met. Specifically, the PAD can respond to the activation instruction of the crab walking function of the vehicle and send a function switch signal to the vehicle controller VCU, which can currently be a function activation signal. At this time, the judgment of the crab walking function fault state by the vehicle motion controller and the judgment of the crab walking function fault state by the vehicle controller can be combined to obtain the judgment result of whether the function activation requirements are met.

[0081] In one embodiment of the present invention, vehicle fault information can be obtained by responding to an activation instruction for the crab steering function of the vehicle, and a fault judgment of the crab steering function can be performed based on whether the vehicle fault information meets a preset activation condition.

[0082] Exemplarily, the preset start condition can be expressed as: 1) when the OK indicator light is OK; the motor start-up flag of the front / left rear / right rear motor control unit FMCU / RLMCU / RRMCU is allowed; 2) the speed valid flag of the front / left rear / right rear motor control unit FMCU / RLMCU / RRMCU is valid; 3) the maximum torque valid flag of the front / left rear / right rear motor control unit FMCU / RLMCU / RRMCU is valid; 4) the drive motor transmission ratio fault state is fault-free; 5) the system status signal of the vehicle motion controller Didyna is valid; 6) the steering wheel angle valid flag is valid; 7) the steering wheel angle calibration flag is calibrated; 8) the steering wheel actual torque valid flag is valid; 9) the vehicle speed signal state is fault-free; 10) the braking depth valid flag is valid; 11) the gear system state is normal; 12) the left / right rear wheel angle valid flag is valid. This embodiment of the present invention is not limited.

[0083] Optionally, when it is determined based on the vehicle fault information that the fault state of the crab steering function is no fault, the crab steering function may be activated.

[0084] In an embodiment of the present invention, when it is determined based on the vehicle driving information and the vehicle environment information that the vehicle meets the preset activation conditions, the crab steering function can be activated and the two rear wheels of the vehicle can be differentially controlled to make the vehicle crab-steering; when it is determined based on the vehicle driving information and the vehicle environment information that the vehicle does not meet the preset activation conditions, the crab steering function is not activated.

[0085] The vehicle driving information may include front wheel steering angle information, gear information and braking depth information, and the vehicle environment information may include slope information.

[0086] The preset activation conditions may include: the front wheel steering angle information does not exceed the preset angle threshold, the slope information does not exceed the preset slope threshold, the braking depth information does not exceed the preset depth threshold and the gear information meets the preset driving information, wherein the preset driving information may include preset traveling information and preset reversing information.

[0087] In the above preset activation conditions, the front wheel steering angle information does not exceed the preset angle threshold, indicating that the vehicle needs to turn within a relatively small angle range; the slope information does not exceed the preset slope threshold, which may be to ensure the stability of the vehicle when moving laterally; the braking depth information does not exceed the preset depth threshold, indicating that the driver does not apply too much braking pressure to allow the vehicle to move laterally; the gear information of the preset travel information and the preset reverse information indicates that the vehicle needs to move laterally in the forward or reverse state.

[0088] For example, the preset activation conditions may be: 1) when the user operates the steering wheel, the front wheel angle is ≤15°; 2) the vehicle is on flat ground, that is, the slope information of the vehicle driving environment is less than a preset slope threshold; 3) the braking depth information is less than a certain threshold; 4) the gear is in the D / R gear. This embodiment of the present invention is not limited to this.

[0089] In actual applications, the vehicle motion controller Didyna obtains the front wheel steering angle from the steering wheel angle signal sent by the steering control system EPS, and when it is determined that the front wheel steering angle is greater than the preset angle threshold, it can send a crab steering function activation instruction to the vehicle controller VCU, that is, the vehicle motion controller Didyna can feed back executable signals to the PAD and the vehicle controller VCU.

[0090] Optionally, when the vehicle motion controller Didyna receives and starts to execute the crab function, the corresponding demand signal can be transmitted to the intelligent integrated braking control system IPB, the steering control system EPS, the rear wheel steering system RWS, the active suspension system Disus and the electronic parking system EPB. In order to ensure the vehicle's passability and steering purpose, if an emergency occurs when the vehicle executes the crab function, the vehicle motion controller Didyna can trigger the execution of EPB for emergency braking to ensure the safety of the vehicle when executing the crab function.

[0091] In one embodiment of the present invention, the torque differential control of the two rear wheels of the vehicle can be specifically performed by distributing the left and right differential torques of the rear axle to achieve the following control: Figure 4 The turning center a shown is adjusted to reduce the turning radius of the vehicle.

[0092] Specifically, the two rear wheels of the vehicle can be differentially torque controlled according to the difference between the front wheel steering angle and the rear wheel steering angle, and the rear axle differential torque. Based on the differential torque control of the rear wheels, the rear wheel steering angle is utilized and the torque of the outer wheels is increased, thereby increasing the control dimension of the vehicle. When turning, the control ability of the vehicle body posture can be effectively enhanced, the turning radius of the vehicle is reduced, and the vehicle makes the turning process smoother.

[0093] In a specific implementation, the rear axle required torque can be determined based on the difference between the front wheel steering angle and the rear wheel steering angle, and then the two rear wheels of the vehicle can be differentially controlled based on the rear axle required torque and the rear axle differential torque to make the vehicle crab-like.

[0094] Among them, the front wheel steering angle is in direct proportion to the steering wheel angle, and the rear axle differential torque may include a rear axle basic differential torque, which can be determined according to a preset corresponding relationship between the steering wheel angle and the steering wheel torque.

[0095] In practical applications, the current steering wheel angle and steering wheel torque can be obtained, and then the rear axle basic differential torque corresponding to the current steering wheel angle and steering wheel torque can be obtained based on a preset query table. Specifically, it can be obtained by looking up an unloading slope table or a steering wheel angle table, which is not limited in the embodiment of the present invention.

[0096] For example, when the steering wheel angle is greater than a preset steering wheel angle threshold, such as 90°, and the steering wheel torque is less than or equal to a preset first torque threshold, such as 1 Nm, and lasts for a certain period of time, such as 100 ms, the rear axle basic differential torque T δIt can be obtained by unloading to 0 Nm according to the unloading slope table; when the steering wheel angle is greater than a preset steering wheel angle threshold, such as 90°, and the steering wheel torque is greater than or equal to a preset second torque threshold, such as 3 Nm, and lasts for a certain period of time, such as 100 ms, the rear axle basic differential torque T δ As another example, when the steering wheel angle is less than a preset steering wheel angle threshold, such as 90°, and the steering wheel torque is greater than or equal to a preset third torque threshold, such as -1Nm, and lasts for a certain period of time, such as 100ms, the rear axle basic differential torque T δ It can be obtained by unloading to 0Nm according to the unloading slope table; when the steering wheel angle is less than the preset steering wheel angle threshold, such as 90°, and the steering wheel torque is less than or equal to the preset fourth torque threshold, such as -3Nm, and lasts for a certain period of time, such as 100ms, the rear axle basic differential torque T δ It can be obtained by looking up a table according to the control vehicle speed and the steering wheel angle. This is not limited in the embodiment of the present invention.

[0097] In the embodiment of the present invention, in order to perform differential torque control on the two rear wheels of the vehicle, in addition to obtaining the rear axle required torque, the rear axle differential torque may also be obtained.

[0098] Specifically, the rear axle differential torque may also include a correction coefficient, and the rear axle differential torque may be obtained by the following formula: rear axle differential torque = rear axle basic differential torque * correction coefficient. The correction coefficient may include one of a braking attenuation coefficient, a rear wheel torque coefficient, and a slope attenuation coefficient, and a combination thereof, and the numerical signs of the differential torques of the two wheels are different.

[0099] Optionally, the rear axle differential torque may further include a correction coefficient and a direction indication value. The rear axle differential torque may be obtained by the following formula: rear axle differential torque = direction indication value * rear axle basic differential torque * correction coefficient. The correction coefficient may include one of a braking attenuation coefficient, a rear wheel torque coefficient, and a slope attenuation coefficient, and a combination thereof. When the vehicle's steering direction is left, the direction indication value is a positive value, and when the vehicle's steering direction is right, the direction indication value is a negative value.

[0100] It should be noted that when the vehicle is turning to the left, the direction indication value is a positive number, and when the vehicle is turning to the right, the direction indication value is a negative number, that is, the numerical signs of the left rear wheel differential torque and the right rear wheel differential torque are different, thereby ensuring that the right rear wheel differential torque is different from the left rear wheel differential torque, and then ensuring that the subsequent left and right rear wheel motors have different torque outputs.

[0101] For example, the specific calculation formula of the rear axle differential torque can be as follows:

[0102] Left rear wheel differential torque = direction indication value of vehicle rotation direction * rear axle basic differential torque Tδ * brake attenuation coefficient * left rear wheel torque coefficient * slope attenuation coefficient * -1;

[0103] Right rear wheel differential torque = direction indication value of vehicle rotation direction * rear axle basic differential torque Tδ * brake attenuation coefficient * right rear wheel torque coefficient * slope attenuation coefficient.

[0104] It should be noted that the brake attenuation coefficient, torque attenuation coefficient, slope attenuation coefficient, etc. can be obtained by looking up the table.

[0105] Examples of relevant tables can be shown in Table 1, Table 2 and Table 3 below:

[0106]

[0107] Table 1

[0108]

[0109] Table 2

[0110]

[0111] Table 3

[0112] Among them, C_APA may refer to a specific vehicle control or data recording system, and the following basic rules are presented in the table: the braking attenuation coefficient is negatively correlated with the braking depth, that is, the more obvious the braking, the smaller the differential torque, the greater the basic differential torque, and the greater the difference in differential torque between the left and right wheels; the slope attenuation coefficient is negatively correlated with the slope, that is, the greater the slope, the smaller the differential torque. This embodiment of the present invention is not limited to this.

[0113] In practical applications, the distributed differential torque may include the left rear wheel differential torque and the right rear wheel differential torque, and the motor target torque may be calculated at this time.

[0114] Specifically, the target torque of the left rear motor can be calculated by obtaining the required torque of the rear axle and then using the required torque of the rear axle and the differential torque of the left rear wheel. The target torque of the right rear motor can also be calculated by using the required torque of the rear axle and the differential torque of the right rear wheel.

[0115] The required torque of the front and rear axles can usually be calculated and allocated by the vehicle's electronic control unit according to the vehicle's dynamic requirements and the driver's operation. In practical applications, the required torque of the rear axle can be calculated based on the difference between the rear axle steering angle and the front axle steering angle when the vehicle is crab-steering. Specifically, it can be expressed as obtaining the rear wheel steering angle limit of the vehicle, and then calculating the steering angle difference between the rear wheel steering angle limit and the front wheel steering angle, and determining the rear axle torque based on the steering angle difference, and using the rear axle torque calculation to obtain the rear axle required torque.

[0116] Exemplarily, the calculation formula of the motor target torque of the crab walking function can be as follows:

[0117] Front motor target torque = front axle required torque;

[0118] Left rear motor target torque = rear axle required torque / 2 + left rear wheel differential torque;

[0119] Right rear motor target torque = rear axle required torque / 2 + right rear wheel differential torque.

[0120] In actual applications, the vehicle controller VCU ultimately transmits the target torque to the MCU control units of the front and rear three motors, specifically the left / right rear wheel target torque.

[0121] Optionally, during the process of performing differential torque control on the two rear wheels of the vehicle, the vehicle may also be subjected to torque zero-crossing smoothing control according to the current vehicle speed and road adhesion coefficient.

[0122] Preferably, it can be specifically manifested as that when the crab steering function is working, the vehicle controller VCU controls the torque to pass smoothly through zero based on parameter dimensions such as the current vehicle speed, steering angle information, and road adhesion coefficient. By combining the intelligent adjustment capabilities of the vehicle controller VCU under different driving conditions, it can ensure the stability of the vehicle at low power output and meet the dynamic response requirements of the vehicle at high power output.

[0123] Specifically, the actual wheel end torque can be determined according to the current vehicle speed and road adhesion coefficient, and based on the torque range of the actual wheel end torque, the torque variation amplitude when the crab function target torque is output can be controlled.

[0124] Exemplarily, the slope of torque loading and unloading can be adjusted under different wheel-end actual torque conditions. For control under low torque conditions, for example, when the absolute value (abs) of the wheel-end actual torque of all wheels is less than 40Nm, the vehicle controller VCU limits the loading and unloading slopes of the front axle target torque, the left rear wheel target torque, and the right rear wheel target torque to be less than or equal to 4Nm, which means that the torque changes slowly in this case to ensure smooth power output and avoid impact on the vehicle; for control under high torque conditions, for example, when the absolute value (abs) of the wheel-end actual torque is greater than 54Nm, the vehicle controller VCU can allow higher front axle target torque, left rear wheel target torque, and right rear wheel target torque loading and unloading slopes to a maximum of, for example, 100Nm, so that when the vehicle already has a higher power output, the vehicle controller VCU allows faster torque adjustment to adapt to more dynamic driving needs.

[0125] Optionally, during the process of performing differential torque control on the two rear wheels of the vehicle, the target torque of the crab function may also be limited according to the road adhesion coefficient.

[0126] Preferably, the target torque of the two rear wheels, i.e., the two rear wheels, can be limited according to the calculation result of TCS (Traction Control System) and the motor capacity. Specifically, when the rear wheel is judged to be slipping based on the road adhesion coefficient, the rear wheel end target torque can be limited based on the rear wheel drive motor torque; when the rear wheel is judged not to be slipping based on the road adhesion coefficient, the rear wheel end target torque can be limited based on the rear wheel drive motor torque and the rear wheel torque limit.

[0127] The limitation of the rear-wheel target torque can be expressed as limiting the target torque of each wheel according to the torque limit value calculated by TCS and the motor capacity. The torque limitation method of the two wheels of the rear axle is the same. Taking the left rear wheel as an example, it can be expressed as when the slip state of the left rear wheel is 0 (that is, no slip), the following torque limitation formula is executed:

[0128] -1*Maximum torque of left rear motor ≤ target torque of left rear wheel ≤ maximum torque of left rear motor

[0129] This shows that under normal circumstances, the target torque of the left rear wheel can be freely adjusted between the maximum positive torque and the maximum negative torque of the motor to meet the power requirements of the vehicle.

[0130] When the left rear wheel slip state is 1 (i.e. slipping), the following torque limiting formula is executed:

[0131] -1*Maximum torque of left rear motor ≤ target torque of left rear wheel ≤ torque value min (Left rear wheel torque limit, left rear motor maximum torque).

[0132] Torque value min The smaller value of the left rear wheel torque limit and the maximum torque of the left rear motor can be selected. Among them, the left rear wheel torque limit can be the torque limit calculated by TCS to prevent the wheel from further slipping, which means that in the slipping state, the target torque upper limit of the left rear wheel can be the smaller value of the torque limit calculated by TCS and the maximum torque of the motor to ensure that the wheel will not continue to slip due to excessive torque.

[0133] Optionally, the wheel slip and locking state may be detected, and the vehicle control strategy may be adjusted accordingly to ensure that the vehicle remains stable and safe under various driving conditions. For example, when a wheel slip or locking trend is detected, the system may reduce the torque output of the motor, or apply brakes to the slipping wheel to restore traction and prevent the vehicle from losing control, which is not limited in the embodiments of the present invention.

[0134] Among them, wheel slip state = left rear wheel slip state || right rear wheel slip state, that is, when one of the left rear wheel or the right rear wheel slips, the vehicle is determined to be in a slip state. Among them, when the difference between the reference vehicle speed (which may be the actual vehicle speed or a certain reference speed) and the crab speed (the speed of the vehicle in the crab mode) is greater than or equal to the preset first vehicle speed threshold, such as 1.5km / h, it can be determined that the wheel has a reverse slip trend, and the wheel locking state can be set to 1 at this time, indicating that the wheel may be about to or is locking; when the difference between the reference vehicle speed and the crab steering speed is less than or equal to the preset second vehicle speed threshold, such as 1km / h, the wheel state can be considered to be recovered, and the wheel locking state can be set to 0 at this time, indicating that the wheel is no longer in a locked state.

[0135] Optionally, during the process of performing differential torque control on the two rear wheels of the vehicle, the current driving trajectory of the vehicle can also be revised according to the yaw angular velocity, and the revised driving trajectory can be output and displayed to assist the owner in driving.

[0136] In a preferred embodiment of the present invention, in the process of controlling the rear wheel steering, the actual yaw rate can also be obtained, and the current trajectory of the vehicle can be corrected based on the actual yaw rate, and the corrected actual turning trajectory of the vehicle can be displayed on the vehicle screen. Figure 2 As shown, specifically, after the vehicle controller VCU receives the crab function activation signal from the vehicle motion controller Didyna, the vehicle controller calculates the torque difference between the left and right wheels of the rear axle and sends the target torque to the MCU for response. At the same time, it can determine the current trajectory correction state and perform trajectory calculation through signals such as the actual yaw angular velocity, and output a trajectory switching signal to the PAD to pop up a panoramic interface in the PAD and display the actual turning trajectory of the vehicle.

[0137] Optionally, the crab steering function of the vehicle can also be exited, and its exit condition can be opposite to the preset crab steering function activation condition, which is not limited in the embodiment of the present invention; the exit condition of the crab steering function can be expressed as follows: when the exit condition is met for a duration exceeding a certain time threshold, such as 1000ms, the rear axle basic differential torque T δ =0 Nm, and the rear wheel steering angle is controlled to return to 0°, to which the embodiment of the present invention is not limited.

[0138] In the embodiment of the present invention, when the crab steering function is activated, the two rear wheels of the vehicle can be controlled to steer in the same direction as the front wheels, and the two rear wheels of the vehicle can be subjected to differential torque control, so as to make up for the difference between the steering angle of the front axle and the steering angle of the rear axle based on the differential torque control, so that the vehicle can crab-steering and achieve a larger angle of crab-steering obstacle avoidance, thereby helping to reduce the turning radius of the vehicle and achieve the purpose of rapid steering or obstacle avoidance in narrow urban spaces. Furthermore, the differential torque control of the two rear wheels of the vehicle can be intervened to achieve point-to-point oblique motion with almost no yaw, thereby increasing the stability of the vehicle during the crab steering process.

[0139] It should be noted that, for the sake of simplicity, the method embodiments are described as a series of action combinations, but those skilled in the art should be aware that the embodiments of the present invention are not limited by the order of the actions described, because according to the embodiments of the present invention, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions involved are not necessarily required by the embodiments of the present invention.

[0140] Reference Figure 5 , shows a structural block diagram of an electric drive system embodiment of the present invention, the electric drive system 5 may specifically include:

[0141] A motor at the front end, such as the first motor 51, is used to output torque to the two front wheels of the vehicle; two motors at the rear end, such as the second motor 52 and the third motor 53, are used to output torque to the two rear wheels of the vehicle respectively, and Figure 1 The control device 54 is shown.

[0142] Specifically, when the vehicle controller VCU monitors the activation of the crab steering function and Didyna sends a large-angle crab steering request, the vehicle controller VCU can perform a target differential torque calculation, and transmit the received executable signal and the calculated left rear wheel motor target torque and right rear wheel motor target torque to the MCU control unit of the front and rear three motors, so that the MCU control unit is ready to execute the torque and differential torque control requirements required for the crab steering function, and respond to the target speed and target torque.

[0143] In actual applications, the vehicle controller VCU ultimately transmits the target torque to the MCU control units of the front and rear three motors, specifically the left / right rear wheel target torque. The MCU control units of the front and rear three motors can control the rear wheel steering according to the target torque of the left rear wheel motor and the target torque of the right rear wheel motor.

[0144] In an embodiment of the present invention, in order to reduce the turning radius of the vehicle, the vehicle controller can output different torques to the left and right and rear wheel motors by receiving the front wheel steering angle controlled by the steering wheel and the activated crab function, so as to make up for the difference between the front axle steering angle and the rear axle steering angle, and achieve a larger angle of crab obstacle avoidance, thereby helping to reduce the turning radius of the vehicle, so that the vehicle can pass more easily on narrow roads and park more easily sideways, so as to achieve the purpose of rapid steering or obstacle avoidance in narrow spaces in the city, thereby improving the vehicle's passability under extreme working conditions and the user's driving experience. Specifically, the corresponding control strategy is determined based on the front wheel steering angle, and based on the three-motor control architecture, the rear wheel steering is combined with the differential torque, and the target driving torque of the front axle motor, the left and right motors of the rear axle are redistributed, and different sizes of driving torque are allocated to the rear wheels on both sides.

[0145] Furthermore, when the front wheel steering angle is greater than a preset angle threshold, the different torques of the motors on both sides of the rear wheels, that is, the intervention of differential torque, can achieve point-to-point oblique movement with almost no sway, thereby increasing the stability of the vehicle during crab turning.

[0146] In addition, the control device provided by the embodiment of the present invention can be applicable to drivers with different experiences and different driving scenarios, and the embodiment of the present invention does not impose any limitation on this.

[0147] An embodiment of the present invention further provides a vehicle, comprising:

[0148] Including the above-mentioned control device or the above-mentioned electric drive system, the vehicle can implement the various processes of the above-mentioned vehicle steering control method embodiment and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0149] An embodiment of the present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the various processes of the above-mentioned vehicle steering control method embodiment are implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0150] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0151] It will be appreciated by those skilled in the art that the embodiments of the present invention may be provided as methods, devices, or computer program products. Therefore, the embodiments of the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the embodiments of the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0152] The embodiments of the present invention are described with reference to flowcharts and / or block diagrams of methods, terminal vehicles (systems), and computer program products according to the embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing terminal vehicle to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing terminal vehicle generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0153] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing terminal vehicle to operate in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0154] These computer program instructions can also be loaded onto a computer or other programmable data processing terminal vehicle so that a series of operating steps are executed on the computer or other programmable terminal vehicle to produce a computer-implemented process, thereby providing instructions executed on the computer or other programmable terminal vehicle for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0155] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present invention.

[0156] Finally, it should be noted that the user information (including but not limited to user vehicle information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant laws, regulations and standards of relevant countries and regions, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0157] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal vehicle including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal vehicle. In the absence of further restrictions, the elements defined by the sentence "including one..." do not exclude the presence of other identical elements in the process, method, article or terminal vehicle including the elements.

[0158] The above is a detailed introduction to a vehicle steering control method, a corresponding control device, a corresponding electric drive system, a corresponding vehicle and a corresponding computer-readable storage medium provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for a person skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A vehicle steering control method, characterized in that: The method comprises: When the crab walking function is activated, the two rear wheels of the vehicle are controlled to steer in the same direction as the front wheels, and the two rear wheels of the vehicle are subjected to differential torque control so as to make the vehicle move in a crab walking manner.

2. The steering control method according to claim 1, characterized in that: The method further comprises: The two rear wheels of the vehicle are controlled to steer to a target steering angle, where the target steering angle is suitable for being set to any value between zero degrees and a steering threshold.

3. The steering control method according to claim 2, characterized in that: The target steering angle is the steering threshold of the rear wheels.

4. The steering control method according to any one of claims 1 to 3, characterized in that: The step of performing differential torque control on the two rear wheels of the vehicle comprises: The two rear wheels of the vehicle are subjected to differential torque control according to the difference between the front wheel steering angle and the rear wheel steering angle, and the rear axle differential torque, so as to make the vehicle perform crab motion.

5. The steering control method according to claim 4, characterized in that: The step of performing torque differential control on the two rear wheels of the vehicle according to the difference between the front wheel steering angle and the rear wheel steering angle and the rear axle differential torque to make the vehicle crab move comprises: Determine the rear axle required torque according to the difference between the front wheel steering angle and the rear wheel steering angle; The two rear wheels of the vehicle are subjected to differential torque control according to the rear axle required torque and the rear axle differential torque, so as to enable the vehicle to perform crab motion.

6. The steering control method according to claim 5, characterized in that: The front wheel steering angle is in direct proportion to the steering wheel angle.

7. The steering control method according to claim 5, characterized in that: The rear axle differential torque includes a rear axle basic differential torque, and the rear axle basic differential torque is determined according to a preset corresponding relationship between a steering wheel angle and a steering wheel torque.

8. The steering control method according to claim 7, characterized in that: The rear axle differential torque also includes a correction coefficient, the rear axle differential torque = the rear axle basic differential torque * the correction coefficient, the correction coefficient includes one of the braking attenuation coefficient, the rear wheel torque coefficient and the slope attenuation coefficient and a combination thereof, and the numerical signs of the differential torques of the two wheels are different.

9. The steering control method according to claim 7, characterized in that: The rear axle differential torque also includes a correction coefficient and a direction indication value, the rear axle differential torque = the direction indication value * the rear axle basic differential torque * the correction coefficient, the correction coefficient includes one of the braking attenuation coefficient, the rear wheel torque coefficient and the slope attenuation coefficient and a combination thereof, when the turning direction of the vehicle is left, the direction indication value is a positive value, and when the turning direction of the vehicle is right, the direction indication value is a negative value.

10. The steering control method according to claim 8 or 9, characterized in that: The braking attenuation coefficient is negatively correlated with the braking depth.

11. The steering control method according to claim 8 or 9, characterized in that: The slope attenuation coefficient is negatively correlated with the slope.

12. The steering control method according to claim 1, characterized in that: The step of performing differential torque control on the two rear wheels of the vehicle to make the vehicle crab motion comprises: When it is determined based on the vehicle driving information and the vehicle environment information that the vehicle meets a preset activation condition, the crab motion function is activated to perform differential torque control on the two rear wheels of the vehicle so as to enable the vehicle to crab motion; When it is determined based on the vehicle driving information and the vehicle environment information that the vehicle does not meet the preset activation condition, the crab steering function is not activated.

13. The steering control method according to claim 12, characterized in that: The vehicle driving information includes front wheel steering angle information, gear position information and braking depth information, and the vehicle environment information includes slope information; The preset activation conditions include: the front wheel steering angle information does not exceed the preset angle threshold, the slope information does not exceed the preset slope threshold, the braking depth information does not exceed the preset depth threshold and the gear information meets the preset driving information, wherein the preset driving information includes preset traveling information and preset reversing information.

14. The steering control method according to claim 4, characterized in that: The method further comprises: The vehicle is subjected to torque zero-crossing smoothing control according to the current vehicle speed and road adhesion coefficient of the vehicle.

15. The steering control method according to claim 14, characterized in that: The method of performing torque zero-crossing smooth control on the vehicle according to the current vehicle speed and road adhesion coefficient of the vehicle includes: Determining the actual wheel end torque according to the current vehicle speed and the road adhesion coefficient of the vehicle; Based on the torque range of the actual wheel end torque, the torque variation amplitude when the crab function target torque is output is controlled.

16. The steering control method according to claim 14, characterized in that: The method further comprises: The target torque of the crab function is limited according to the road adhesion coefficient.

17. The steering control method according to claim 16, characterized in that: The limiting of the target torque of the crab function according to the road adhesion coefficient includes: When it is determined based on the road adhesion coefficient that the rear wheel is slipping, limiting the rear wheel end target torque based on the rear wheel drive motor torque; When it is determined based on the road adhesion coefficient that the rear wheels are not slipping, the rear wheel end target torque is limited based on the rear wheel drive motor torque and the rear wheel torque limit.

18. The steering control method according to claim 4, characterized in that: The method further comprises: The current driving trajectory of the vehicle is revised according to the yaw rate.

19. The steering control method according to claim 18, characterized in that: The method further comprises: The output displays the revised driving trajectory to assist the vehicle owner in driving.

20. A control device, characterized in that: It comprises a controller component, a memory and a computer program stored in the memory, and when the computer program is executed by the controller component, the steering control method of the vehicle as claimed in any one of claims 1 to 19 is implemented.

21. The control device according to claim 20, characterized in that: The controller assembly includes a vehicle controller, a vehicle motion controller and a motor control unit.

22. The control device according to claim 21, characterized in that The whole vehicle controller performs a fault judgment on the crab walking function and sends a crab walking function fault instruction to the whole vehicle motion controller; the whole vehicle motion controller performs a fault judgment on the crab walking function again based on the crab walking function fault instruction.

23. The control device according to claim 21, characterized in that The whole vehicle motion controller sends a crab function activation instruction to the whole vehicle controller, and the whole vehicle controller makes a crab function activation judgment based on the crab function activation instruction.

24. The control device according to claim 20, characterized in that The controller assembly also includes a display, which is used to respond to a crab crawl function activation instruction and display a driving trajectory of the vehicle during crab crawling.

25. An electric drive system, characterized in that: The electric drive system comprises: A motor at the front end, used to output torque to two front wheels of the vehicle; Two motors at the rear end are used to output torque to the two rear wheels of the vehicle respectively; And, a control device as claimed in any one of claims 20 to 24.

26. A vehicle, characterized in that: include: A control device as claimed in any one of claims 20 to 24; or comprising an electric drive system as claimed in claim 25.

27. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steering control method of the vehicle as claimed in any one of claims 1 to 19 is implemented.

Images