Method for controlling a vehicle turn and vehicle

Abstract

This application provides a vehicle turning control method and a vehicle. The method includes at least: determining whether a convenient steering mode is active when the vehicle is turning; if the convenient steering mode is active, determining a target control strategy for reducing the turning radius based on the vehicle's driving information; controlling the inner rear wheel to slip based on the target strategy to generate a slip force; and enhancing the driving force of the outer rear wheel; so that the vehicle reduces its turning radius under the action of the slip force and the driving force. This solution reduces the turning radius by addressing slip and enhanced driving force from two active control directions, achieving a large reduction in turning radius quickly and improving control effectiveness. The target control strategy can be determined based on driving information to meet actual needs, offering high flexibility.

Description

Technical Field

[0001] This application relates to vehicle control technology, and more particularly to a method for controlling vehicle turning and a vehicle. Background Technology

[0002] With the continuous development of vehicle technology, urban traffic environments are becoming increasingly complex, and scenarios such as narrow streets and tight parking spaces place higher demands on the low-speed maneuverability of vehicles.

[0003] How to effectively reduce the turning radius and improve steering flexibility under low-speed turning conditions, thereby significantly enhancing the vehicle's maneuverability in scenarios such as parking and U-turns in narrow spaces, has become an important issue that needs to be addressed in the field of vehicle development. Summary of the Invention

[0004] To address the aforementioned problems, this application provides at least one vehicle turning control method and vehicle. This solution reduces the turning radius by employing two active control directions: slip and enhanced drive. It can quickly achieve a significant reduction in turning radius, thus improving control effectiveness. Furthermore, it can determine the target control strategy that meets actual needs based on driving information, offering high flexibility.

[0005] The technical solution of this application is implemented as follows: In a first aspect, this application provides a vehicle turning control method, which includes at least: determining whether a convenient steering mode is active when the vehicle is turning; if the convenient steering mode is active, determining a target control strategy for reducing the turning radius based on the vehicle's driving information; controlling the inner rear wheel to slip and generate a slip force based on the target strategy; and enhancing the driving force of the outer rear wheel; so that the vehicle reduces its turning radius under the action of the slip force and the driving force; wherein the inner rear wheel is the rear wheel on the inside of the curve when turning; and the outer rear wheel is the rear wheel on the outside of the curve when turning.

[0006] Secondly, this application provides a vehicle turning control device, which includes at least: The first determining unit is used to determine whether the convenient steering mode is active when the vehicle is turning.

[0007] The second determining unit is used to determine a target control strategy for reducing the turning radius based on the vehicle's driving information when the convenient steering mode is determined to be active.

[0008] The control unit is used to control the slippage of the inner rear wheel based on the target strategy, generating a slippage force; and to enhance the driving force of the outer rear wheel; so that the vehicle reduces its turning radius under the action of slippage force and driving force; the inner rear wheel is the rear wheel on the inside of the curve when turning; the outer rear wheel is the rear wheel on the outside of the curve when turning.

[0009] Thirdly, this application provides an electronic device, including a memory and a processor, wherein the memory stores a computer program or instructions, and when the computer program or instructions are executed by the processor, the method provided in the first aspect is implemented.

[0010] In one possible implementation, the electronic device may be deployed in a controller within the vehicle, which controls the inner and outer rear wheels of the vehicle to implement the method provided in the first aspect.

[0011] Fourthly, this application also provides a storage medium storing a computer program or instructions that, when executed by a processor, implement any of the methods provided in the first aspect above.

[0012] Fifthly, this application also provides a computer program product comprising a computer program or instructions that, when executed by a processor, implement any of the methods provided in the first aspect above.

[0013] In this solution, the vehicle can activate a convenient steering mode to reduce the turning radius when turning. It can determine the target control strategy to meet the actual needs based on driving information, which is highly flexible. When controlling the vehicle, the target control strategy generates a slip force by controlling the slip of the inner rear wheel and enhances the driving force of the outer rear wheel. Since the directions of these two forces are opposite, reducing the turning radius by focusing on slip and enhanced driving force can quickly achieve a large reduction in the turning radius, thus improving the control effect. Moreover, the slip force and the method of increasing driving force do not result in a loss of power or a sense of jerking, and the user experience is also high. Attached Figure Description

[0014] Figure 1 This is a schematic flowchart of a first optional method for controlling vehicle turning provided in an embodiment of this application; Figure 2 This is a schematic diagram of a second optional process for a vehicle turning control method provided in an embodiment of this application; Figure 3 A schematic diagram of a third optional process for a vehicle turning control method provided in an embodiment of this application; Figure 4 A schematic flowchart illustrating a fourth optional method for controlling vehicle turning provided in an embodiment of this application; Figure 5 A schematic flowchart illustrating a fifth optional method for controlling vehicle turning provided in an embodiment of this application; Figure 6 A schematic flowchart illustrating a sixth optional method for controlling vehicle turning provided in an embodiment of this application; Figure 7A schematic flowchart illustrating a seventh optional method for controlling vehicle turning provided in an embodiment of this application; Figure 8 A schematic flowchart illustrating a seventh optional method for controlling vehicle turning provided in an embodiment of this application; Figure 9 A schematic diagram of an optional structure of the agile steering system provided in an embodiment of this application; Figure 10 This is an optional schematic diagram illustrating the control logic and flow of Scheme 1 provided in the embodiments of this application; Figure 11 This is an optional schematic diagram of the principle block diagram of Scheme 1 provided in the embodiment of this application; Figure 12 This is an optional schematic diagram illustrating the control logic and flow of Scheme 2 provided in the embodiments of this application; Figure 13 This is an optional schematic diagram of the principle block diagram of Scheme 2 provided in the embodiments of this application; Figure 14 This is a schematic diagram of an optional structure of the vehicle turning control device provided in an embodiment of this application.

[0015] It should be noted that the terms "first" and "second" mentioned above are only used to distinguish between different options and do not represent the degree of superiority or inferiority of the options or their priority in the implementation process. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the specific technical solutions of the application will be further described in detail below with reference to the accompanying drawings of the embodiments of this application. The following embodiments are used to illustrate this application, but are not intended to limit the scope of this application.

[0017] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0018] In the following description, the terms "first," "second," and "third" are used only to distinguish different objects and do not represent a specific order of objects, nor are they constituting a chronological order. It is understood that "first," "second," and "third" may be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0020] This application provides a vehicle turning control method, apparatus, vehicle, storage medium, and program product. The following describes various embodiments of the vehicle turning control method, apparatus, vehicle, storage medium, and program product provided in this application.

[0021] In a first aspect, embodiments of this application provide a vehicle turning control method, which can be executed by a vehicle turning control device, which can be deployed in an electronic device or a vehicle and implemented by a program stored in a memory by a processor.

[0022] The following section uses a vehicle as an example to explain the control method for turning the vehicle.

[0023] In some embodiments, reference Figure 1 The process may include, but is not limited to, S101 to S103 described below.

[0024] S101. When the vehicle is turning, determine whether the convenient steering mode is activated.

[0025] Convenient Steering Mode is a general term for technologies that aim to significantly reduce the turning radius of a vehicle. It is mainly achieved through rear-wheel steering. This greatly improves the vehicle's maneuverability in tight spaces and enhances driving stability at high speeds.

[0026] Traditional steering is typically achieved through front-wheel control. In Convenience mode, the rear wheels can also participate in the steering process, assisting the front wheels in turning and reducing the turning radius.

[0027] The convenient steering mode can be applied to the following scenarios: Scenario 1: U-turn and low-speed turning scenario.

[0028] In the city's streets and alleys or narrow underground parking garages, this technology allows an extra-long vehicle to have the agility of a small car, easily completing a U-turn and completely solving the problem of "difficulty in turning".

[0029] Scenario 2: High-speed cornering or lane changing.

[0030] In addition to reducing the turning radius, it also allows the rear wheels to deflect in the same direction as the front wheels when changing lanes or cornering at high speeds (usually above 60 km / h). This provides a sense of stability, similar to "sliding," reducing the tendency for the vehicle to sideslip and fishtail, and improving safety at high speeds.

[0031] The active state indicates that the convenient steering mode is activated, which assists in steering the vehicle. The inactive state indicates that the convenient steering mode is not activated, and steering is achieved by controlling the front wheels.

[0032] Whether a mode is active can be determined by whether the activation conditions are met. If the activation conditions are met, the mode will enter the convenient turning mode.

[0033] Activation conditions may include: receiving a manual trigger command to activate the convenient steering mode.

[0034] In U-turn and low-speed turning scenarios, activation conditions may also include: the current vehicle speed is lower than the first vehicle speed threshold, and the steering wheel angle is greater than the first turning angle threshold. In high-speed cornering or lane-changing scenarios, activation conditions may also include: the current vehicle speed is greater than the second vehicle speed threshold, and the steering wheel angle is greater than the second steering angle threshold.

[0035] The second vehicle speed threshold is greater than the first vehicle speed threshold, and the second turning angle threshold is less than the first turning angle threshold. The values ​​of the first vehicle speed threshold, the second vehicle speed threshold, the first turning angle threshold, and the second turning angle threshold are configured according to actual needs.

[0036] In the active state, execute S102 as follows. In the inactive state, use the original turning control method to control the vehicle to turn.

[0037] S101 can be implemented as follows: when the vehicle turns, first determine whether the activation conditions of the convenient steering mode are met. If the activation conditions are met, control the convenient steering mode to enter the activated state; if the activation conditions are not met, control the convenient steering mode to remain in the inactive state.

[0038] S102. When it is determined that the convenient steering mode is active, a target control strategy for reducing the turning radius is determined based on the vehicle's driving information.

[0039] Driving information is used to select a target control strategy. Driving information may include, but is not limited to, at least one of the following: steering wheel angle, vehicle speed, and estimated road surface adhesion coefficient.

[0040] The target control strategy is used to control the rear wheel auxiliary steering in order to achieve the goal of reducing the turning radius.

[0041] The target control strategy here can be a fixed default control strategy or a control strategy that can be dynamically selected based on the actual driving scenario of the vehicle.

[0042] S103. The vehicle controls the inner rear wheel to slip based on the target strategy, generating a slip force; and enhances the driving force of the outer rear wheel; so that the vehicle reduces its turning radius under the action of slip force and driving force.

[0043] The inner rear wheel is the rear wheel on the inside of the curve when turning; the outer rear wheel is the rear wheel on the outside of the curve when turning.

[0044] Slip force refers to the backward force generated by a vehicle due to slippage.

[0045] Driving force refers to the power generated by the vehicle's electric motor when the vehicle is not slipping.

[0046] The slip force is opposite to the driving force. The slip force acts on the inner rear wheel, while the driving force acts on the outer rear wheel. This creates a rotational tendency similar to circling through the action of the two rear wheels, thus helping to reduce the turning radius.

[0047] The vehicle actively controls the motor of the inner rear wheel through a target strategy, causing it to produce a slight, controllable slip, generating a rearward slip force. Simultaneously, it increases the driving force of the outer rear wheel, generating a forward driving force. These two forces are unequal in magnitude and opposite in direction, with their points of application located on the inner and outer sides of the rear axle, respectively. This creates a yaw moment on the rear axle about the vehicle's vertical axis. This moment's direction is consistent with the turning direction, effectively reducing the vehicle's turning radius and significantly improving low-speed maneuverability. The vehicle achieves a smaller turning radius without significantly increasing the front wheel steering angle, thus significantly improving maneuverability and handling agility in confined spaces.

[0048] In this method, the front wheels retain their original steering control strategy. For example, the front wheels control steering based on the steering force applied by the user to the steering wheel.

[0049] In this embodiment, the vehicle can activate a convenient steering mode to reduce the turning radius when turning. The target control strategy can be determined based on driving information to meet actual needs, which is highly flexible. When controlling the vehicle, the target control strategy generates a slip force by controlling the slip of the inner rear wheel and enhances the driving force of the outer rear wheel. Since the directions of these two forces are opposite, reducing the turning radius by focusing on slip and enhanced driving force can quickly achieve a large reduction in the turning radius, thus improving the control effect. Moreover, the slip force and the method of increasing driving force do not result in a loss of power or a sense of jerking, and the user experience is also high.

[0050] The following explains the process of determining a target control strategy for reducing the turning radius based on the vehicle's driving information, in step S102, when the convenient steering mode is determined to be active.

[0051] In one possible implementation, refer to Figure 2 The process may include, but is not limited to, S201 and S202 described below.

[0052] S201. Estimated values ​​of steering wheel angle, vehicle speed, and road surface adhesion coefficient in the vehicle's driving information.

[0053] In vehicle driving information, steering wheel angle refers to the absolute angle (usually measured in degrees) at which the driver turns the steering wheel, which can be directly measured by an angle sensor installed on the steering column.

[0054] Vehicle speed is the longitudinal speed of a vehicle relative to the ground. It is usually calculated by wheel speed sensors in combination with the wheel rolling radius, or provided by the vehicle's inertial navigation system.

[0055] The road surface adhesion coefficient estimate is the estimate of the maximum friction force between the tire and the road surface. It can be calculated online based on information such as wheel speed, vehicle speed, driving force / braking force, etc., using dynamic models (such as recursive least squares, Kalman filtering, etc.) to determine whether the road surface is wet, slippery, icy, or snowy.

[0056] S202. The vehicle selects a target control strategy based on the estimated values ​​of steering wheel angle, vehicle speed, and road surface adhesion coefficient.

[0057] The target control strategy includes at least one of the first control strategy, the second control strategy, and the third control strategy.

[0058] In the first control strategy, both the inner and outer rear wheels of the vehicle are controlled by rotational speed; in the second control strategy, the inner rear wheels are controlled by rotational speed and the outer rear wheels are controlled by torque; in the third control strategy, the inner rear wheels are controlled by slip ratio and the outer rear wheels are controlled by torque.

[0059] Therefore, the first control strategy can also be called the dual-wheel speed control strategy, the second control strategy can also be called the single-wheel speed control strategy, and the third control strategy can also be called the single-wheel slip ratio control strategy.

[0060] For example, the first control strategy (using speed control for both inner and outer rear wheels) can be applied to conditions with extremely large steering wheel angles, extremely low vehicle speeds, and high road surface adhesion coefficients. At this time, the vehicle is in a very low-speed, large-angle turn (such as a U-turn or parking in a narrow space). Due to the extremely low vehicle speed and good adhesion, the required yaw torque can be effectively generated by directly controlling the speed of the inner and outer rear wheels, without worrying about tire slippage or loss of control.

[0061] The second control strategy (inner rear wheel speed control, outer rear wheel torque control) is suitable for conditions with larger steering wheel angles, lower vehicle speeds, and moderate road surface adhesion (wet or snowy). At this point, if the vehicle speed increases slightly, applying speed control to the outer rear wheels might cause excessive slippage; therefore, torque control is used instead to provide smoother driving force. Speed ​​control is still applied to the inner rear wheels to limit their speed and assist in cornering, making it suitable for low-speed sharp turns on wet or slippery surfaces.

[0062] The third control strategy (inner rear wheel slip ratio control and outer rear wheel torque control) is applicable to conditions with larger steering wheel angles, slightly higher vehicle speeds (e.g., 20-60 km / h), and lower road surface adhesion coefficients (icy, snowy, or wet roads). At these speeds, directly controlling the inner rear wheel speed can easily lead to instability. Therefore, slip ratio control is used to keep the inner rear wheel near its optimal slip ratio to generate maximum lateral force. Torque control is used on the outer rear wheel to dynamically adjust the driving force, thereby achieving stable and effective cornering assistance on low-traction surfaces and preventing fishtailing or understeer.

[0063] If the first condition is met, the first control strategy can be selected as the target control strategy.

[0064] The first condition may include: the turning angle is greater than the third turning angle threshold and the vehicle speed is lower than the third vehicle speed threshold; the first condition may also include: the turning angle is greater than the third turning angle threshold, the vehicle speed is lower than the third vehicle speed threshold, and the estimated value of the road surface adhesion coefficient is greater than the first adhesion coefficient threshold.

[0065] For example, when the turning angle is extremely large and the vehicle speed is extremely low, the first control strategy is selected as the target control strategy.

[0066] If the second condition is met, the second control strategy can be selected as the target control strategy.

[0067] The second condition may include: the turning angle is greater than the third turning angle threshold, the estimated road surface adhesion coefficient is greater than the first adhesion coefficient threshold and less than the second adhesion coefficient threshold; the second condition may also include: the turning angle is greater than the third turning angle threshold, the estimated road surface adhesion coefficient is greater than the first adhesion coefficient threshold and less than the second adhesion coefficient threshold, and the vehicle speed is lower than the third vehicle speed threshold.

[0068] For example, when the steering wheel angle is large, the vehicle speed is low, and the road surface adhesion coefficient is moderate, the second control strategy is selected as the target control strategy.

[0069] If the third condition is met, the third control strategy can be selected as the target control strategy.

[0070] The third condition may include: the turning angle is greater than the third turning angle threshold, the estimated value of the road surface adhesion coefficient is greater than the second adhesion coefficient threshold, and the vehicle speed is greater than the third vehicle speed threshold.

[0071] For example, under conditions of large steering wheel angle, slightly higher vehicle speed (e.g., 20-60 km / h), and low road surface adhesion coefficient (icy or waterlogged roads), the third control strategy is selected as the target control strategy.

[0072] This allows for full-condition adaptive operation: At extremely low speeds, large turning angles, and high-friction surfaces (such as U-turns on narrow roads), dual-speed control maximizes the speed difference between the inner and outer wheels, achieving the minimum turning radius and significantly improving maneuverability. At slightly higher speeds and low-friction surfaces (such as slippery curves), inner slip ratio control and outer torque control suppress wheel slippage, preventing fishtailing or understeer and ensuring driving stability. It also balances smoothness and safety: the second and third strategies employ outer torque control to avoid impacts or dragging sensations on the outer wheels due to excessive speed limiting, resulting in smoother cornering; simultaneously, precise control of the inner wheel speed or slip ratio ensures accurate and controllable yaw torque. Furthermore, it reduces reliance on driver skill: the vehicle automatically matches the optimal control mode, reducing the driver's workload on complex road surfaces or sharp curves, making the vehicle both agile and easy to control.

[0073] In one possible implementation, the target control strategy can also be determined based on the user's selection. For example, user 1 can choose a first control strategy as the default target control strategy, and user 2 can choose a second control strategy as the default target control strategy. This approach can satisfy the user experience.

[0074] The following explains the process in S103 where the vehicle controls the inner rear wheel to slip based on the target strategy, generating a slip force, and enhances the driving force of the outer rear wheel, so that the vehicle reduces its turning radius under the action of the slip force and the driving force.

[0075] The process may include, but is not limited to, any one of the following methods 1 to 3.

[0076] Method 1: When the target strategy is the first control strategy, the inner rear wheel is controlled to slip based on the first control strategy to generate slip force; and the driving force of the outer rear wheel is enhanced; so that the vehicle's turning radius is reduced under the action of slip force and driving force.

[0077] Method 2: When the target strategy is the second control strategy, the inner rear wheel is controlled to slip based on the second control strategy to generate slip force; and the driving force of the outer rear wheel is enhanced; so that the vehicle's turning radius is reduced under the action of slip force and driving force.

[0078] Method 3: When the target strategy is the third control strategy, the inner rear wheel is controlled to slip based on the third control strategy to generate slip force; and the driving force of the outer rear wheel is enhanced; so that the vehicle's turning radius is reduced under the action of slip force and driving force.

[0079] In Method 1, when the target policy is the first control policy, refer to Figure 3 The process may include, but is not limited to, S301 to S304 described below.

[0080] S301. Based on the vehicle's current speed, determine the theoretical rotational speed of the outer rear wheel and the theoretical rotational speed of the inner rear wheel.

[0081] The theoretical rotational speed is the wheel speed at which a vehicle can travel at its current speed without slipping.

[0082] Based on the Ackermann steering geometry and the current vehicle speed, the vehicle calculates the rotational speed of the outer rear wheel and the speed of the inner rear wheel when the vehicle is traveling at the current speed (i.e., turning) without slipping. These are used as the theoretical rotational speeds of the outer and inner rear wheels.

[0083] For example, according to Ackermann steering geometry, when a vehicle is turning, the steering centerlines of all wheels intersect at a single point. At this time, the turning radius of the outer rear wheel is larger than that of the inner rear wheel. Combining the current vehicle speed (usually referring to the vehicle's center of gravity speed) and parameters such as wheelbase and track width, the yaw rate of the vehicle around the instantaneous steering center can be calculated first. Then, multiply this yaw rate by the actual turning radius of the inner and outer rear wheels to obtain their respective theoretical linear velocities. Finally, dividing by the wheel rolling radius yields the theoretical rotational speed. The rotational speeds of the inner and outer rear wheels calculated in this way allow the wheels to roll purely without longitudinal slippage.

[0084] S302. Based on the vehicle speed, steering wheel angle, and target reduction in turning radius, determine the compensating target yaw moment for the target reduction in turning radius.

[0085] The inherent Ackerman turning radius of the vehicle can be determined based on the current vehicle speed and steering wheel angle. A desired reduction in turning radius is then added to obtain the target turning radius. Based on this, and using a vehicle dynamics model (such as a two-degree-of-freedom reference model), the additional yaw rate or lateral acceleration change required to achieve this target radius is calculated. This is then converted into a target yaw moment generated by the longitudinal force difference between the inner and outer wheels. This compensating yaw moment serves as the input for the subsequent distribution of motors between the inner and outer rear wheels, thereby achieving active reduction of the turning radius.

[0086] S303. Based on the theoretical speed of the outer rear wheel, the theoretical speed of the inner rear wheel, and the target yaw moment, the vehicle determines the target speed of the outer rear wheel and the target speed of the inner rear wheel.

[0087] The target speed of the outer rear wheel is used to enhance the driving force of the outer rear wheel, while the target speed of the inner rear wheel is used to generate slip force by slipping the inner rear wheel.

[0088] Based on the theoretical speeds of the outer and inner rear wheels (i.e., pure rolling speeds under no-slip conditions), and combined with the target yaw moment, a difference allocation strategy is used to determine the target speeds of the inner and outer rear wheels: to achieve an additional yaw moment in the same direction as the turning direction, the outer rear wheel speed typically needs to be greater than its theoretical speed (increasing driving force), while the inner rear wheel experiences slight slippage. Specifically, based on the target yaw moment, wheel rolling radius, and track width, the required longitudinal force difference is calculated, then converted into speed compensation for the inner and outer wheels, and added to their respective theoretical speeds to obtain the target speeds of the outer rear wheel (theoretical value + compensation) and the inner rear wheel (theoretical value - compensation). In this way, by controlling the speed difference between the inner and outer rear wheels, the target yaw moment can be precisely generated, achieving an active reduction in the turning radius.

[0089] S304. The vehicle controls the outer rear motor and the inner rear motor respectively based on the target speed of the outer rear wheel and the target speed of the inner rear wheel, so as to make the inner rear wheel slip and generate slip force; and enhance the driving force of the outer rear wheel.

[0090] Based on the calculated target speeds of the outer and inner rear wheels, the vehicle independently controls the motors driving the outer and inner rear wheels respectively: Increased drive torque is applied to the outer rear motor, raising its actual speed above its theoretical pure rolling speed, thus enhancing driving force; decreased drive torque or even active braking is applied to the inner rear motor, lowering its actual speed below its theoretical pure rolling speed, thereby generating controllable longitudinal slip and creating a slip force pointing towards the corner's center. This creates a significant speed difference between the inner and outer rear wheels, which, under the influence of the wheelbase, generates an additional yaw moment in the same direction as the turning direction, ultimately achieving the effect of actively reducing the turning radius and improving low-speed maneuverability.

[0091] The control process of a motor can be either open-loop control or closed-loop control.

[0092] In this way, by independently controlling the speed of the inner and outer rear drive wheels, a wheel speed difference much greater than that of the Ackermann geometry can be actively created. This causes the inner rear wheel to slip and the outer rear wheel to receive enhanced drive, thereby obtaining the maximum additional yaw moment, significantly shortening the vehicle's turning diameter, and even approaching a U-turn on the spot. Precise low-speed maneuverability: Closed-loop speed control eliminates the nonlinearity of torque distribution in traditional differentials, allowing the driver to obtain a wide range of body yaw response with only a small angle of steering wheel rotation, reducing the driving burden of repeated adjustments in confined spaces. Fast dynamic response: Direct motor control of speed avoids torque response lag, achieving a "control-and-turn" feel, improving the vehicle's controllability and safety in low-speed handling extreme scenarios.

[0093] Next, based on the theoretical speeds of the outer rear wheel, the inner rear wheel, and the target yaw moment of the vehicle in S303, the target speeds of the outer rear wheel and the inner rear wheel are determined.

[0094] refer to Figure 4 The process may include, but is not limited to, S401 to S404 described below.

[0095] S401. Based on the vehicle's first parameters, find the matching first speed change in the first relationship.

[0096] The first speed change is used to enhance the driving force of the outer rear wheel; the first relationship includes the speed change corresponding to different first parameters when the slip ratio meets the first range.

[0097] The first parameter is used to help determine the change in rotational speed of the outer rear wheel. This rate of change in rotational speed is used to enhance the driving force of the outer rear wheel.

[0098] The first parameter may include at least one of the following: accelerator pedal torque, vehicle speed, and target yaw moment.

[0099] The first relation can be in tabular or text format, etc.

[0100] The first relationship can be obtained through calibration. For example, the calibration process may include: first, fixing the vehicle on a typical low- or high-friction surface, setting different vehicle speeds, accelerator pedal openings (corresponding to torque requirements), and desired target yaw moments; then, by gradually adjusting the speed change of the outer rear wheel, measuring the actual additional yaw moment and vehicle response (such as yaw rate and lateral acceleration), and recording the optimal speed compensation value that keeps the vehicle stable and achieves the expected reduction in turning radius. Multiple sets of calibration data (first parameter combination → first speed change) are then compiled into a table or fitted as a curve to obtain the first relationship. To cover all operating conditions, the above process needs to be repeated under different road surface adhesion coefficients (dry, wet, ice and snow), and the boundary areas are refined using interpolation or extrapolation methods. Finally, the calibrated mapping relationship is solidified into the controller for real-time table lookup calculations.

[0101] Based on the vehicle's primary parameters (such as accelerator pedal torque, vehicle speed, or target yaw moment), a matching primary speed change is retrieved from a preset primary relationship (which may be in the form of a table, mapping curve, or text rules). This speed change is used to actively increase the drive speed of the outer rear wheel when the slip ratio is within a specific primary range, thereby enhancing its driving force. The primary relationship is typically obtained through bench testing or real-vehicle calibration and reflects the amount of outer wheel speed compensation required to generate the desired additional yaw moment under different operating conditions. For example, when the accelerator pedal torque is large or the target yaw moment is high, the primary speed change obtained from the table increases accordingly; while when the vehicle speed increases, this change may be appropriately reduced to prevent instability. In this way, the vehicle can dynamically adjust the driving force of the outer rear wheel, working in conjunction with the inner rear wheel to achieve precise turning radius control.

[0102] S402. The vehicle determines the target speed of the outer rear wheel based on the theoretical speed of the outer rear wheel and the first speed change.

[0103] For example, the target speed of the outer rear wheel is determined by summing the theoretical speed of the outer rear wheel and the initial speed change. Of course, if other factors are considered, the target speed of the outer rear wheel can also be obtained by superimposing the speed changes under the influence of other factors.

[0104] S403. Based on the first parameter, find the matching second speed change in the second relationship.

[0105] The second rotational speed change is used to generate slip force; the second relationship includes the second rotational speed variables corresponding to different first parameters when the slip ratio meets the first range.

[0106] The second relationship can be in tabular or text format, etc.

[0107] The second relationship can be obtained through calibration. For example, the calibration process may include: first, fixing the vehicle on a typical low- or high-friction surface, setting different vehicle speeds, accelerator pedal openings (corresponding to torque requirements), and desired target yaw moment; then, by gradually adjusting the speed change of the inner rear wheel, measuring the actual additional yaw moment and vehicle response (such as yaw rate and lateral acceleration), and recording the optimal speed compensation value that maintains vehicle stability and achieves the expected reduction in turning radius. Multiple sets of calibration data (first parameter combination → second speed change) are then compiled into a table or fitted as a curve to obtain the second relationship. To cover all operating conditions, the above process needs to be repeated under different road surface adhesion coefficients (dry, wet, ice and snow), and interpolation or extrapolation methods are used to refine the boundary areas. Finally, the calibrated mapping relationship is solidified into the controller for real-time table lookup calculations.

[0108] Based on a first parameter of the vehicle (such as accelerator pedal torque, vehicle speed, or target yaw moment), a matching second speed change is retrieved from a preset second relationship (which may be in the form of a table, mapping curve, or text rules). This speed change is used to compensate for slight slippage of the inner rear wheel when the slip ratio is within a specific first range. In this way, the vehicle can dynamically adjust the inner rear wheel to work in conjunction with the outer rear wheel to achieve precise turning radius control.

[0109] S404. Based on the theoretical speed of the inner rear wheel and the second speed change, determine the target speed of the inner rear wheel.

[0110] For example, the target speed of the inner rear wheel is determined by summing the theoretical speed of the inner rear wheel and the second speed change. Of course, if other factors are considered, the target speed of the outer inner wheel can be obtained by superimposing the speed changes under the influence of other factors.

[0111] In this way, the first and second speed changes under various scenarios can be determined in advance through calibration. Then, the compensation speed can be obtained by directly looking up the first and second relationships, thereby obtaining the target speeds of the inner and outer rear wheels. This method features fast response speed and low latency.

[0112] The following explains the process in S304 where the vehicle controls the outer rear motor and the inner rear motor respectively based on the target speed of the outer rear wheel and the target speed of the inner rear wheel, so as to cause the inner rear wheel to slip and generate slip force, and enhance the driving force of the outer rear wheel.

[0113] In one possible implementation, refer to Figure 5 The process may include, but is not limited to, S501 and S502 described below.

[0114] S501 employs a proportional-integral-derivative control algorithm to control the output torque of the outer rear motor, so that the output speed of the outer rear motor follows the target speed of the outer rear wheel, thereby enhancing the driving force of the outer rear wheel through the target speed of the outer rear wheel.

[0115] To achieve precise enhancement of the outer rear wheel drive force, the vehicle can employ a Proportional-Integral-Derivative (PID) control algorithm for closed-loop speed control of the outer rear motor. The target speed of the outer rear wheel is used as a setpoint, and the current actual speed of the motor is used as feedback. The deviation between the two is input to the PID controller. The controller calculates the required motor output torque based on the proportional, integral, and derivative components of the deviation, and adjusts the drive torque of the outer rear motor in real time, ensuring that the actual speed quickly and stably follows the target speed. Since the target speed is set to a value higher than its theoretical pure rolling speed based on the desired additional yaw moment, when the outer rear motor follows this target speed, its output drive force naturally exceeds the basic drive force required to maintain pure rolling. This achieves active enhancement of the outer rear wheel drive force, providing the necessary additional yaw moment to reduce the turning radius.

[0116] S502 uses a proportional-integral-derivative control algorithm to control the output torque of the inner rear motor so that the output speed of the inner rear motor follows the target speed of the inner rear wheel. The inner rear wheel slips and generates a slipping force by using the target speed of the inner rear wheel.

[0117] To achieve controllable slippage of the inner rear wheel to generate auxiliary steering force, the vehicle employs a proportional-integral-derivative (PID) control algorithm for closed-loop speed control of the inner rear motor. The target speed of the inner rear wheel is used as a setpoint (typically lower than its theoretical pure rolling speed), and the motor's current actual speed is used as feedback. The deviation between these two values ​​is calculated by the PID controller to determine the required output torque. This torque acts on the inner rear motor, forcing its actual speed towards the lower target speed, thus generating continuous braking slippage at the inner rear wheel. Because the target speed is lower than the theoretical pure rolling speed, the longitudinal slip ratio between the tire and the road surface increases, generating a lateral slip force along the vehicle's side. This slip force, together with the enhanced driving force of the outer rear wheel, forms an additional yaw moment around the vehicle's center of gravity, effectively reducing the turning radius. The PID controller adjusts the torque in real time to ensure the slippage remains stable within the target range, preventing wheel lock-up or excessive slippage.

[0118] In this way, the PID controller adjusts the motor torque in real time based on the deviation between the actual speed and the target speed, enabling rapid response to driving intentions and changes in operating conditions (such as sudden steering or sudden changes in road adhesion). This allows the inner rear wheel to quickly reach the low speed required for slippage, while simultaneously allowing the outer rear wheel to rapidly increase to the target speed to enhance driving force, thereby generating the necessary additional yaw torque in a timely manner. It also eliminates steady-state errors: the integral term eliminates static errors during speed tracking, ensuring that the actual motor speed converges precisely to the target speed, avoiding insufficient or excessive slippage due to long-term deviations, thus ensuring a continuous and stable reduction in turning radius. In summary, the PID control algorithm, in achieving closed-loop tracking of rear wheel speed, balances response speed, accuracy, smoothness, and engineering practicality.

[0119] The method for determining the target reduction in turning radius is explained below.

[0120] In one possible implementation, the target reduction in turning radius is determined based on the vehicle speed and steering wheel angle; different vehicle speeds and steering wheel angles correspond to different target reductions.

[0121] The optimal target reduction in turning radius is pre-calibrated based on the vehicle's speed and steering wheel angle. When the vehicle turns, the target reduction in turning radius that matches the current speed and steering wheel angle is directly retrieved.

[0122] The calibration process may include selecting multiple vehicle speeds (such as 5 km / h, 10 km / h, 20 km / h). The calibration process uses a combination of vehicle speed and steering wheel angle (e.g., half a turn, one turn, extreme turning angle) as the reference point. For each combination point, the target reduction amount is gradually adjusted based on subjective evaluation (driver's perception of steering agility and stability) and objective measurements (actual turning radius, yaw rate, lateral acceleration, etc.). For example, at extremely low speeds and large turning angles, the target reduction amount is gradually increased until the vehicle approaches the edge of instability, then adjusted back by a certain margin, recording the value that minimizes the turning radius while maintaining vehicle control. At higher speeds, the reduction amount needs to be limited to prevent fishtailing. The data from each calibration point is compiled into a two-dimensional table with vehicle speed and steering wheel angle as the horizontal and vertical axes, with the middle area supplemented by linear interpolation, ultimately yielding the target turning radius reduction under all operating conditions. This calibration result ensures that the vehicle achieves the best turning assistance effect that balances agility and safety in different usage scenarios.

[0123] By calibrating the target reduction of the turning radius based on vehicle speed and steering wheel angle, it can achieve full-condition adaptability: the maximum reduction of the turning radius is obtained at extremely low speeds and large turning angles to improve maneuverability, while the reduction is automatically limited at high speeds and small turning angles to ensure safety and stability; at the same time, it integrates subjective driving experience with objective yaw response, making the control effect both agile and smooth; lookup table calibration simplifies online calculations, making it easy to quickly adjust for different vehicle models, ultimately reducing the driver's operating burden in scenarios such as low-speed U-turns and parking on narrow roads, and suppressing the tendency of fishtailing and understeer when changing lanes or cornering at high speeds, significantly improving the overall vehicle's handling flexibility, comfort and safety.

[0124] In another possible implementation, the target reduction in turning radius can be determined based on the user's selection. For example, multiple levels of target reduction in turning radius can be pre-configured, and the user can select the desired target reduction in turning radius via voice or touch commands on the vehicle. This also adapts to the user experience.

[0125] In method 2, when the target policy is the second control policy, refer to Figure 6 The process may include, but is not limited to, S601 to S605 described below.

[0126] S601. Determine the target rotational speed of the inner rear wheel based on the target reduction in turning radius.

[0127] The implementation of S601 can be referred to the relevant description of determining the target speed of the inner rear wheel in Method 1, which will not be repeated here.

[0128] S602. Based on the target speed of the inner rear wheel, control the inner rear motor to cause the inner rear wheel to slip and generate a slipping force.

[0129] The implementation of 602 can be found in the description of controlling the inner rear motor in Method 1, which will not be repeated here.

[0130] S603. Based on the target yaw moment and the actual moment of the inner rear wheel, determine the compensation moment of the outer rear wheel.

[0131] The target yaw moment is the compensating moment used to reduce the target's reduction in turning radius.

[0132] The vehicle first determines the actual compensation torque of the inner rear wheel at the target speed, and then removes the influence of the actual compensation torque of the inner rear wheel at the target speed from the target yaw torque to obtain the compensation torque for the outer rear wheel.

[0133] S604. Based on the compensation torque of the outer rear wheel and the basic torque of the outer rear wheel, determine the target torque of the outer rear wheel.

[0134] The vehicle determines the target torque of the outer rear wheel as the sum of the compensating torque of the outer rear wheel and the basic torque of the outer rear wheel.

[0135] S605, controls the outer rear motor based on the target torque of the outer rear wheel to enhance the driving force of the outer rear wheel.

[0136] The vehicle sends the target torque of the outer rear wheel to the outer rear motor, which in turn controls the outer rear wheel based on the target torque of the outer rear wheel, thereby enhancing the driving force of the outer rear wheel.

[0137] In the second control strategy, the inner rear wheel uses speed control and the outer rear wheel uses torque control, which can improve stability while ensuring response speed. The inner rear wheel quickly generates the required wheel speed difference through precise speed closed-loop control, producing a slip force to assist cornering; the outer rear wheel no longer forces a certain speed, but directly outputs drive torque that matches the target yaw moment, avoiding insufficient traction or excessive braking caused by the limited speed of the outer wheel. This strategy is suitable for medium speeds and medium coefficient of friction surfaces (such as wet or dry curves), effectively reducing the turning radius and preventing the outer wheel from slipping, ensuring smooth vehicle posture and no abrupt yaw impact when entering and exiting corners, achieving a good trade-off between flexibility and stability.

[0138] The following explains the process of determining the target rotational speed of the inner rear wheel based on the target reduction in turning radius in S601.

[0139] refer to Figure 7 The process may include, but is not limited to, S701 and S702 described below.

[0140] S701. Determine the target slip ratio based on the target reduction in turning radius.

[0141] Different target reductions in turning radius correspond to different target slip ratios. These target slip ratios are obtained through pre-calibration. When the vehicle achieves convenient steering, the target slip ratio is determined directly based on the target reduction in turning radius.

[0142] The process of calibrating multiple slip ratios can include: for the target vehicle model, on typical low-friction or high-friction road surfaces, setting a series of desired turning radius reductions (e.g., from 0 cm to the maximum reduction, divided into certain steps). For each preset reduction, the braking or driving force of the inner rear wheel is adjusted to bring the vehicle's actual turning radius to the target, and the longitudinal slip ratio of the inner rear wheel at this point is recorded as the target slip ratio corresponding to that reduction. To eliminate dynamic errors, each calibration point needs to be repeated multiple times and averaged, while also considering corrections for interference factors such as vehicle speed and steering wheel angle. Finally, the data from each calibration point (turning radius reduction → target slip ratio) are compiled into a table or fitted as a curve for the control system to use for real-time table lookup. This calibration ensures that the control system can accurately obtain the required inner wheel slip ratio target based on the desired radius reduction, thereby achieving precise turning assistance through slip ratio closed-loop control.

[0143] S702. Based on the target slip ratio and the theoretical speed of the inner rear wheel, determine the target speed of the inner rear wheel.

[0144] The theoretical rotational speed is the rotational speed of the wheels of a vehicle that does not slip when traveling at the current vehicle speed.

[0145] For example, the target speed of the inner rear wheel can be determined according to the first formula.

[0146] The first formula may include: ; In the first formula, The target speed indicating the target rotational speed of the inner rear wheel. This indicates the theoretical rotational speed of the inner rear wheel. This indicates the target slip ratio.

[0147] In method 3, when the target policy is the third control policy, refer to Figure 8 The process may include, but is not limited to, S801 to S805 described below.

[0148] S801. Determine the target slip ratio based on the target reduction in turning radius.

[0149] For implementation details, please refer to the detailed description in S701; they will not be repeated here.

[0150] S802. Based on the target slip ratio and the actual slip ratio, a proportional-integral-derivative control algorithm is used to control the output torque of the inner rear wheel so that the actual slip ratio of the inner rear wheel follows the target slip ratio. The target slip ratio causes the inner rear wheel to slip, generating a slip force.

[0151] To achieve precise control of the slip force of the inner rear wheel, the third control strategy employs slip ratio closed-loop control instead of direct speed closed-loop control. First, the actual slip ratio of the inner rear wheel is calculated in real-time based on the current vehicle speed and wheel speed. Then, the target slip ratio (calibrated from the desired reduction in turning radius) is used as a setpoint, and the actual slip ratio is used as a feedback quantity; the deviation between the two is input to the PID controller. The PID controller dynamically calculates the required adjustment amount of output torque to be applied to the inner rear motor based on the magnitude, cumulative trend, and rate of change of the deviation. When the actual slip ratio is lower than the target slip ratio (insufficient to generate the required slip force), the controller instructs the motor to increase braking torque (or decrease drive torque), further reducing wheel speed and increasing the slip ratio until the target value is reached. Conversely, if the actual slip ratio exceeds the target value (with a tendency to lock up), the braking torque is reduced or the drive torque is increased, causing the slip ratio to decrease. By adjusting the motor torque in real time, the slip ratio is stabilized near the target value, thereby achieving steady-state slip of the inner rear wheel and generating continuous and controllable lateral slip force, providing a stable additional yaw moment to reduce the turning radius. This process is particularly suitable for low-to-medium grip surfaces or medium-speed conditions, avoiding fishtailing due to excessive slip ratio or insufficient effect due to insufficient slip ratio.

[0152] S803. Based on the target yaw moment and the actual moment of the inner rear wheel, determine the compensation moment of the outer rear wheel.

[0153] The target yaw moment is the compensating moment used to reduce the target's reduction in turning radius.

[0154] For implementation details, please refer to the detailed description in S703; they will not be repeated here.

[0155] S804. Based on the compensation torque of the outer rear wheel and the basic torque of the outer rear wheel, determine the target torque of the outer rear wheel.

[0156] For implementation details, please refer to the detailed description in S704; they will not be repeated here.

[0157] S805: Control the outer rear motor based on the target torque of the outer rear wheel to enhance the driving force of the outer rear wheel.

[0158] For implementation details, please refer to the detailed description in S705; they will not be repeated here.

[0159] Under the third control strategy (inner rear wheel slip ratio control + outer rear wheel torque control), the vehicle can achieve stable and efficient cornering assistance at medium speeds or on low-traction surfaces. The inner rear wheel is precisely controlled near the target slip ratio through a closed-loop slip ratio control system, generating continuous and controllable lateral slip force to avoid the risk of instability caused by wheel lock-up or excessive slippage. The outer rear wheel uses direct torque control to dynamically adjust the driving force to match the required additional yaw moment, while avoiding traction fluctuations caused by forced speed limiting. This strategy effectively balances the reduction of turning radius with driving stability, and is especially suitable for low-traction corners such as wet, slippery, and icy surfaces, significantly suppressing fishtailing or understeer tendencies and improving driving safety and smoothness.

[0160] The following example illustrates a control scheme for vehicle turning.

[0161] With the rapid development of new energy vehicle technology, distributed electric drive systems, due to their ability to independently and precisely control the torque / speed of each wheel, have brought new possibilities to vehicle chassis dynamics control. In low-speed steering conditions, reducing the turning radius and improving steering agility has always been an important issue in enhancing vehicle maneuverability (especially when parking or making U-turns in tight spaces).

[0162] Among related technologies, the main means of improving vehicle steering performance include: Rear-wheel active steering (RWS): This system uses mechanical or electronic means to make the rear wheels turn in the same or opposite direction as the front wheels, thereby changing the vehicle's steering characteristics. However, this system requires an additional steering actuator, is complex in structure, and has a high cost. It mainly affects stability at medium and high speeds, and has limited improvement on the minimum turning radius at extremely low speeds.

[0163] Torque vectoring: This technique utilizes the differential torque between the left and right drive wheels to generate a yaw moment that makes the vehicle easier to steer. It's a commonly used technology in distributed drive vehicles. However, traditional torque vectoring control is primarily based on the distribution of torque commands. At extremely low speeds and large steering angles, differential torque alone may not be sufficient to fully utilize the friction characteristics between the tires and the road surface to maximize the reduction of the turning radius.

[0164] Brake-assisted steering: This assists steering by applying braking force to the inner wheels, but this results in a loss of power and may cause an uncomfortable jerk.

[0165] Most related technologies focus on improving steering through differential torque, braking torque, or in conjunction with rear wheel steering angle. However, no technical solution has yet been found that explicitly proposes and systematically addresses the goal of actively and significantly reducing the turning radius at extremely low speeds by actively and precisely controlling the speed of the rear axle drive motor (especially inducing a controllable slip ratio in the inner drive wheel) and coordinating it with a torque distribution strategy. Existing solutions, when utilizing the physical phenomenon of tire slip friction, are mostly passive results or simple braking triggers, lacking an active, smooth, and controllable closed-loop speed control strategy.

[0166] Therefore, it is necessary to propose a new agile steering technology based on active control of motor speed to improve the steering flexibility of vehicles at low speeds more effectively and smoothly.

[0167] The core inventive concept of this embodiment is to abandon the traditional approach of simply relying on torque difference or complex mechanical steering mechanism to assist steering, and instead make full use of the characteristic that the speed of each motor in the distributed electric drive system can be independently controlled in a closed loop. By actively controlling the speed relationship between the left and right drive wheels of the rear axle, especially by strategically making the inner rear wheel of the turn generate a controllable, low positive slip ratio, and at the same time coordinating the drive state of the outer rear wheel, a strong yaw moment that helps to reduce the turning radius is actively generated.

[0168] Its core principle can be summarized as follows: 1. The principle of "weakening the inner wheel and strengthening the outer wheel" in generating a torque: When a vehicle is turning, by controlling the slight slippage of the inner rear wheel relative to the ground, the rolling resistance of that wheel is changed, or even a certain slip force is generated; at the same time, the driving traction of the outer rear wheel is maintained or enhanced. This pair of horizontal forces acting on the rear axle of the vehicle in opposite directions will form a yaw moment that makes the vehicle rotate more actively around its instantaneous steering center, thereby effectively reducing the turning radius.

[0169] 2. Speed ​​control as a direct execution method: Motor speed control can directly and quickly affect the rotation state of the wheels, thereby precisely regulating the slip relationship between the tire and the ground. By setting a "target speed" slightly lower than its pure rolling theoretical value for the inner rear wheel, and using the motor's powerful speed regulation capability to stabilize it at this state, the expected slight slip can be reliably and repeatably induced.

[0170] 3. Coordination and Division of Labor with Torque Control: This embodiment does not exclude torque control but incorporates it into the collaborative framework. For example, in the "single-wheel speed control" scheme, the outer rear wheel still uses torque control to provide stable basic driving force or additional thrust; while the inner rear wheel is dedicated to achieving slippage through speed control. The commands for both are ultimately unified as the torque output of the motor, but the control objectives and closed-loop logic are different.

[0171] This embodiment provides three implementation schemes, all with the same system configuration, the main difference being the combination of control modes for the two motors on the rear axle.

[0172] (I) Overall System Composition.

[0173] refer to Figure 9 The agile steering system shown in this embodiment is applied to a distributed drive new energy vehicle, which includes: a perception layer 901, a decision control layer 902, and an execution layer 903.

[0174] The perception layer 901 includes: a steering wheel angle sensor, a vehicle speed sensor, and wheel speed sensors for each wheel.

[0175] Decision control layer 902: includes vehicle control unit (VCU) or dedicated chassis domain controller, with the agile steering control module of this embodiment embedded within it.

[0176] Execution layer 903: includes the left rear axle motor (driving the left rear wheel) and the right rear axle motor (driving the right rear wheel). Both motors can operate independently in torque control mode or speed control mode and have a rapid mode switching capability.

[0177] Vehicle parameters: wheelbase, track width, steering ratio, tire radius, reduction ratio of each motor, etc.

[0178] (II) Scheme 1: Dual-wheel speed control scheme.

[0179] When the Agile Steering function is activated, this solution switches both the left and right rear axle motors to speed control mode.

[0180] The control logic and process of Scheme 1 can be referenced. Figure 10 The contents shown include, but are not limited to, S1001 to S1006 below.

[0181] S1001, Status monitoring and function enable judgment.

[0182] The vehicle speed v and steering wheel angle δsw are acquired in real time. When the vehicle speed is detected to be lower than a preset threshold (e.g., 15 kph) and the absolute value of the steering wheel angle is greater than a preset activation angle (e.g., more than 5° corresponding to the front wheel angle), the agile steering mode is entered.

[0183] S1002. Calculate the theoretical reference wheel speed and the target yaw moment.

[0184] Based on the Ackermann steering geometry and vehicle speed, calculate the theoretical rotational speeds ωrl_theory and ωrr_theory of the left and right rear wheels under no-slip conditions. Simultaneously, based on the current steering wheel angle, vehicle speed, and the target turning radius reduction ΔRdes(v) (e.g., a reduction of 0.4m at 5 kph), calculate the additional target yaw moment ΔMz_des required based on the vehicle dynamics model.

[0185] S1003, Generate target speed command for rear axle dual wheels.

[0186] The target speed for the outer rear wheel is: ωrr_target = ωrr_theory + Δω. Here, Δω is a speed increment calculated based on ΔMz_des and vehicle parameters, designed to provide stronger traction to the outer wheel.

[0187] Target speed of the inner rear wheel: ωrl_target = ωrl_theory α Δω. Here, α>1 is a gain coefficient that ensures the target rotational speed of the inner wheel is significantly lower than its theoretical pure rolling value, thereby actively inducing a positive slip ratio λtarget (e.g., 5%-15%). λtarget can be adaptively adjusted according to road surface adhesion conditions.

[0188] S1004, Speed ​​closed-loop control.

[0189] ωrl_target and ωrr_target are sent as commands to the left and right rear motor controllers, respectively. The motor controllers use PID and other control algorithms to quickly and accurately adjust the motor output torque, ensuring that the actual wheel speed tracks the target rotational speed.

[0190] S1005, Front axle control.

[0191] If the vehicle is equipped with a drive motor, the front axle motor maintains the original torque demand control for the driver, or is coordinated according to the vehicle's power distribution strategy.

[0192] S1006, Function Exit.

[0193] When the vehicle speed rises to the exit threshold (e.g., 15 kph), or the steering wheel angle is less than a certain value, or the slope is greater than a certain value, or the yaw rate is greater than a safe value, the rear axle motor smoothly switches back to torque control mode, ending the agile steering function.

[0194] The principle block diagram of Scheme 1 can be referred to. Figure 11 The contents shown include the vehicle controller 1101, the left and right rear electric drive controllers 1102, the left rear electric drive 1103, and the right rear electric drive 1104.

[0195] The inputs include: steering wheel angle, vehicle speed, accelerator pedal opening, slope, yaw rate, etc. The "target speed decision module" in the vehicle model of the vehicle controller 1101 makes a target speed decision, generates the target speed of the left and right rear wheels, and then outputs motor torque commands through two independent "speed PID controllers" to act on the vehicle model, ultimately reducing the turning radius. The entire system constitutes a closed-loop control.

[0196] (III) Scheme 2: Single wheel speed control scheme.

[0197] When the Agile Steering function is activated, this solution only switches the inner rear axle motor to speed control mode, while the outer motor remains in torque control mode.

[0198] The control logic and process of Scheme 2 can be referenced. Figure 12 The contents shown include, but are not limited to, S1201 to S1206 below.

[0199] S1201, Status monitoring and function enable judgment.

[0200] Refer to the description of Option 1.

[0201] S1202, Calculate the theoretical reference wheel speed and the target yaw moment.

[0202] Refer to the description of Option 1.

[0203] S1203, Generate heterogeneous control instructions.

[0204] Inner rear wheel (speed control): Calculate its target speed ωrl_target = ωrl_theory (1 λtarget), where λtarget is the desired slip ratio, which is directly mapped from the reduction in the target turning radius.

[0205] Outer rear wheel (torque control): Calculate its target torque Trr_target = Trear_base + ΔT. Where Trear_base is the base drive torque of the rear axle (which may be zero), and ΔT is the torque increment (positive value) calculated based on the target yaw moment ΔMz_des.

[0206] S1204, heterogeneous closed-loop control.

[0207] Inner rear wheel: Tracks ωrl_target via a speed PID controller.

[0208] Outer rear wheel: Directly output torque command Trr_target.

[0209] S1205, Front axle control.

[0210] S1206, Function Exit.

[0211] This design allows the inner wheel to focus on generating slip through precise speed control, while the outer wheel focuses on providing thrust through torque control, resulting in a clear division of labor.

[0212] The principle block diagram of Scheme 2 can be referred to. Figure 13 The contents shown include the vehicle controller 1301, the left and right rear electric drive controllers 1302, the left rear electric drive 1303, and the right rear electric drive 1304.

[0213] The difference from Scheme 1 is that the control paths of the two actuators on the rear axle are different: the inner one is "target speed -> speed PID -> torque", and the outer one is "target torque -> direct output".

[0214] (iv) Key algorithm modules.

[0215] Target yaw moment mapping module: Stores or calculates online the ΔMz_des (target yaw moment) required to achieve the desired reduction in turning radius at different vehicle speeds v and steering wheel angles δsw. This is a two-dimensional lookup table or a simple function.

[0216] Speed ​​command decision module: Converts ΔMz_des into specific left and right rear wheel speed commands (Scheme 1) or "inner speed + outer torque" commands (Scheme 2). This involves vehicle parameters and slip ratio targets.

[0217] Mode smooth switching module: Ensures that the output is smooth and shock-free when the motor switches between torque control and speed control modes. It usually uses command gradual change or state observer smooth transition.

[0218] Option 3: Control scheme based on direct slip ratio closed loop.

[0219] In Scheme 3, instead of directly setting the target speed, the target slip ratio λtarget is used as the direct control target. The controller calculates the actual slip ratio λactual of the inner rear wheel in real time: λactual = (ωwheel) R v) / v, and through a slip ratio PID controller, the output adjusts the motor torque so that λactual tracks λtarget. The control of the outer wheel can be similar to that in Scheme 2.

[0220] This approach requires more precise vehicle speed and wheel speed signals, and the slip ratio calculation may be sensitive to noise at high vehicle speeds and low slip ratios. However, its control objective is more direct.

[0221] Option 4: Hybrid control scheme integrating torque vectoring.

[0222] Based on single-wheel speed control, specifically Scheme 2, a hybrid control approach of "torque as the primary factor and speed limiting as a secondary factor" is also adopted for the outer rear wheel. This means the outer wheel primarily executes torque commands, but its wheel speed is simultaneously monitored to ensure its slip ratio does not exceed a safe upper limit (preventing slippage), forming a double closed-loop structure.

[0223] This increases the robustness of the control and prevents the outer wheel from slipping unexpectedly on low-friction surfaces, but the control logic is slightly more complex.

[0224] Option 5: Multi-mode adaptive switching scheme.

[0225] Based on the steering wheel angle, vehicle speed range, and estimated road surface adhesion coefficient, the system adaptively selects between "dual-wheel speed control," "single-wheel speed control," or the traditional "torque vector control." For example, dual-wheel speed control is used at extremely large steering angles and extremely low vehicle speeds; single-wheel speed control is used at medium steering angles or low-friction surfaces; and torque vectoring is used entirely at high speeds or small steering angles.

[0226] This solution is more intelligent and can leverage the advantages of various control strategies, but it requires more complex upper-level decision-making logic and state recognition algorithms.

[0227] These alternative solutions all remain within the core inventive concept of "assisting steering by actively controlling the rear wheel speed (slippage)," and are enrichments and extensions of the specific implementation of this embodiment.

[0228] The technical effects of this embodiment may include: 1. More significant reduction in turning radius: By actively controlling the inner rear wheel to generate controllable slip, the steering rolling resistance is directly reduced. Combined with the thrust of the outer wheel, the generated yaw moment is more direct and powerful than a simple torque vector, enabling a smaller turning radius at extremely low speeds.

[0229] 2. More precise control and faster response: The closed-loop control of motor speed has extremely high bandwidth and precision, enabling direct and precise control of tire slippage. It is more direct and faster than the method of inversely calculating torque distribution through complex dynamic models.

[0230] 3. Improved smoothness: Speed ​​control enables smooth establishment and deslip of slip ratio, avoiding the jerking sensation caused by traditional brake-assisted steering and improving driving comfort.

[0231] 4. Fully utilizes the characteristics of electric drive, with a simple structure: No need to add any mechanical hardware such as rear wheel steering, only through software algorithm upgrades, it fully utilizes the control freedom of the existing three-electric drive system, with low cost and easy implementation.

[0232] 5. Highly adaptable: The target turning radius can be linearly adjusted according to the real-time vehicle speed (e.g., 40cm reduction from 5kph, with the reduction decreasing as the vehicle speed increases), achieving smooth entry and exit of the function and adapting to different working conditions.

[0233] 6. Two optimization paths are provided: dual-wheel speed control offers better overall coordination; single-wheel speed control has a clear division of labor, which may be more conducive to controller resource allocation and algorithm simplification. These two solutions offer options for vehicle models with different needs.

[0234] Secondly, embodiments of this application provide a vehicle turning control device, referring to... Figure 14 As shown, the vehicle turning control device 140 may include: a first determining unit 1401, a second determining unit 1402, and a control unit 1403.

[0235] The first determining unit 1401 is used to determine whether the convenient steering mode is active when the vehicle is turning.

[0236] The second determining unit 1402 is used to determine a target control strategy for reducing the turning radius based on the vehicle's driving information when it is determined that the convenient steering mode is active.

[0237] The control unit 1403 is used to control the inner rear wheel to slip based on the target strategy, thereby generating a slip force; and to enhance the driving force of the outer rear wheel; so that the vehicle reduces its turning radius under the action of slip force and driving force; the inner rear wheel is the rear wheel on the inside of the curve when turning; the outer rear wheel is the rear wheel on the outside of the curve when turning.

[0238] In some embodiments, the second determining unit 1402 is further configured to: acquire steering wheel angle, vehicle speed, and road surface adhesion coefficient estimates from driving information; select a target control strategy based on the steering wheel angle, vehicle speed, and road surface adhesion coefficient estimates; the target control strategy includes at least one of a first control strategy, a second control strategy, and a third control strategy; wherein, in the first control strategy, both the inner and outer rear wheels of the vehicle are controlled by speed; in the second control strategy, the inner rear wheels are controlled by speed and the outer rear wheels are controlled by torque; and in the third control strategy, the inner rear wheels are controlled by slip ratio and the outer rear wheels are controlled by torque.

[0239] In some embodiments, when the target strategy is the first control strategy, the control unit 1403 is further configured to: determine the theoretical rotational speed of the outer rear wheel and the theoretical rotational speed of the inner rear wheel based on the current vehicle speed; the theoretical rotational speed is the wheel speed at which the vehicle travels at the current speed without slipping; determine a target yaw moment to compensate for the target reduction in turning radius based on the vehicle speed, steering wheel angle, and target reduction in turning radius; determine the target rotational speed of the outer rear wheel and the target rotational speed of the inner rear wheel based on the theoretical rotational speed of the outer rear wheel, the theoretical rotational speed of the inner rear wheel, and the target yaw moment; the target rotational speed of the outer rear wheel is used to enhance the driving force of the outer rear wheel, and the target rotational speed of the inner rear wheel is used to generate slip force by slipping the inner rear wheel; control the outer rear motor and the inner rear motor respectively based on the target rotational speed of the outer rear wheel and the target rotational speed of the inner rear wheel to cause the inner rear wheel to slip and generate slip force; and enhance the driving force of the outer rear wheel.

[0240] In some embodiments, the control unit 1403 is further configured to: search for a matching first speed change in a first relationship based on a first parameter of the vehicle; the first speed change is used to enhance the driving force of the outer rear wheel; the first relationship includes speed changes corresponding to different first parameters when the slip ratio meets a first range; determine a target speed of the outer rear wheel based on the theoretical speed of the outer rear wheel and the first speed change; search for a matching second speed change in a second relationship based on the first parameter; the second speed change is used to generate slip force; the second relationship includes second speed variables corresponding to different first parameters when the slip ratio meets a first range; and determine a target speed of the inner rear wheel based on the theoretical speed of the inner rear wheel and the second speed change.

[0241] In some embodiments, the control unit 1403 is further configured to: employ a proportional-integral-derivative (PID) control algorithm to control the output torque of the outer rear motor so that the output speed of the outer rear motor follows the target speed of the outer rear wheel, thereby enhancing the driving force of the outer rear wheel through the target speed of the outer rear wheel; employ a PID control algorithm to control the output torque of the inner rear motor so that the output speed of the inner rear motor follows the target speed of the inner rear wheel, thereby causing the inner rear wheel to slip and generating a slipping force through the target speed of the inner rear wheel.

[0242] In some embodiments, the control unit 1403 is further configured to: determine the target reduction amount of the turning radius based on the vehicle speed and steering wheel angle; different vehicle speeds and steering wheel angles correspond to different target reduction amounts.

[0243] In some embodiments, when the target strategy is the second control strategy, the control unit 1403 is further configured to: determine the target rotational speed of the inner rear wheel based on the target reduction in turning radius; control the inner rear motor based on the target rotational speed of the inner rear wheel to cause the inner rear wheel to slip and generate a slipping force; determine the compensation torque of the outer rear wheel based on the target yaw moment and the actual torque of the inner rear wheel; the target yaw moment is the compensation torque used for the target reduction in turning radius; determine the target torque of the outer rear wheel based on the compensation torque of the outer rear wheel and the base torque of the outer rear wheel; and control the outer rear motor based on the target torque of the outer rear wheel to enhance the driving force of the outer rear wheel.

[0244] In some embodiments, the control unit 1403 is further configured to: determine a target slip ratio based on the target reduction in turning radius; and determine a target rotational speed of the inner rear wheel based on the target slip ratio and the theoretical rotational speed of the inner rear wheel; the theoretical rotational speed is the rotational speed of the wheel at which the vehicle does not slip when traveling at the current vehicle speed.

[0245] In some embodiments, when the target strategy is the third control strategy, the control unit 1403 is further configured to: determine a target slip ratio based on the target reduction in turning radius; control the output torque of the inner rear wheel using a proportional-integral-derivative (PID) control algorithm based on the target slip ratio and the actual slip ratio, so that the actual slip ratio of the inner rear wheel follows the target slip ratio, and the inner rear wheel slips through the target slip ratio to generate a slip force; determine the compensation torque of the outer rear wheel based on the target yaw moment and the actual torque of the inner rear wheel; the target yaw moment is the compensation torque used for the target reduction in turning radius; determine the target torque of the outer rear wheel based on the compensation torque of the outer rear wheel and the base torque of the outer rear wheel; and control the outer rear motor based on the target torque of the outer rear wheel to enhance the driving force of the outer rear wheel.

[0246] It should be noted that the communication device of the application provided in this application embodiment includes all the units included, which can be implemented by a processor in an electronic device; of course, it can also be implemented by specific logic circuits; in the implementation process, the processor can be a central processing unit (CPU), a microprocessor (MPU), a digital signal processor (DSP), or a field-programmable gate array (FPGA), etc.

[0247] The descriptions of the above device embodiments are similar to those of the above method embodiments, and have similar beneficial effects. For technical details not disclosed in the device embodiments of this application, please refer to the descriptions of the method embodiments of this application for understanding.

[0248] It should be noted that, in the embodiments of this application, if the above-described vehicle driving control method is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the embodiments of this application, or the part that contributes to the related technology, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), magnetic disks, or optical disks. Thus, the embodiments of this application are not limited to any specific hardware and software combination.

[0249] Thirdly, embodiments of this application provide an electronic device, including a memory and a processor. The memory stores a computer program or instructions, and when the computer program or instructions are executed by the processor, they implement the method provided in the first aspect.

[0250] In one possible implementation, the electronic device may be deployed in a controller within the vehicle, which controls the inner and outer rear wheels of the vehicle to implement the method provided in the first aspect.

[0251] Fourthly, embodiments of this application provide a storage medium, namely a computer-readable storage medium, on which a computer program or instructions are stored, which, when executed by a processor, implement the steps of any of the methods provided in the first aspect of the above embodiments.

[0252] Fifthly, embodiments of this application provide a computer program product, which includes a computer program or instructions that, when executed by a processor, implement the steps of any of the methods provided in the first aspect of the above embodiments.

[0253] It should be noted that the descriptions of the above embodiments of storage media, devices, apparatuses, and program products are similar to the descriptions of the above method embodiments and have similar beneficial effects. For technical details not disclosed in the embodiments of storage media, devices, apparatuses, and program products of this application, please refer to the descriptions of the method embodiments of this application for understanding.

[0254] It should be understood that the phrase "one embodiment" or "an embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "in one embodiment" or "in some embodiments" appearing throughout the specification do not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It should be understood that in the various embodiments of this application, the sequence numbers of the above-described processes do not imply a sequential order of execution; the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application. The sequence numbers of the above-described embodiments are merely descriptive and do not represent the superiority or inferiority of the embodiments.

[0255] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0256] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods, such as: multiple units or components can be combined, or integrated into another electronic device, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the various components shown or discussed can be through some interfaces, and the indirect coupling or communication connection between devices or units can be electrical, mechanical, or other forms.

[0257] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units. They may be located in one place or distributed across multiple network units. Some or all of the units may be selected to achieve the purpose of this embodiment according to actual needs.

[0258] In addition, each functional unit in the various embodiments of this application can be integrated into one processing unit, or each unit can be a separate unit, or two or more units can be integrated into one unit; the integrated unit can be implemented in hardware or in the form of hardware plus software functional units.

[0259] Those skilled in the art will understand that all or part of the steps of the above method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments. The aforementioned storage medium includes various media that can store program code, such as mobile storage devices, read-only memory (ROM), magnetic disks, or optical disks.

[0260] Alternatively, if the integrated units described above are implemented as software functional modules and sold or used as independent products, they can also be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the embodiments of this application, or the parts that contribute to related technologies, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as mobile storage devices, ROMs, magnetic disks, or optical disks.

[0261] The above are merely embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A control method of a vehicle turning, characterized by, The method includes: When the vehicle is turning, determine whether the convenient steering mode is activated; When it is determined that the convenient steering mode is active, a target control strategy for reducing the turning radius is determined based on the vehicle's driving information. Based on the target strategy, the inner rear wheel is controlled to slip, generating a slip force; and the driving force of the outer rear wheel is enhanced; so that the vehicle reduces its turning radius under the action of the slip force and the driving force; the inner rear wheel is the rear wheel on the inside of the curve when turning; the outer rear wheel is the rear wheel on the outside of the curve when turning.

2. The method of claim 1, wherein, The determination of a target control strategy for reducing the turning radius based on the vehicle's driving information includes: Obtain the estimated values ​​of steering wheel angle, vehicle speed, and road surface adhesion coefficient from the driving information; Based on the estimated values ​​of steering wheel angle, vehicle speed, and road surface adhesion coefficient, the target control strategy is selected; the target control strategy includes at least one of a first control strategy, a second control strategy, and a third control strategy. In the first control strategy, both the inner and outer rear wheels of the vehicle are controlled by rotational speed; in the second control strategy, the inner rear wheel is controlled by rotational speed and the outer rear wheel is controlled by torque; in the third control strategy, the inner rear wheel is controlled by slip ratio and the outer rear wheel is controlled by torque.

3. The method according to claim 1 or 2, characterized in that, When the target strategy is the first control strategy, the inner rear wheel is controlled to slip based on the target strategy, generating a slip force; And enhance the driving force of the outer rear wheel, including: Based on the current vehicle speed, determine the theoretical rotational speed of the outer rear wheel and the theoretical rotational speed of the inner rear wheel; the theoretical rotational speed is the wheel speed at which the vehicle can travel at the current speed without slipping. Based on the vehicle speed, steering wheel angle, and target reduction in turning radius, a compensating target yaw moment is determined to reduce the turning radius by the target reduction. Based on the theoretical speed of the outer rear wheel, the theoretical speed of the inner rear wheel, and the target yaw moment, the target speeds of the outer and inner rear wheels are determined; the target speed of the outer rear wheel is used to enhance the driving force of the outer rear wheel, and the target speed of the inner rear wheel is used to generate slip force by the slip of the inner rear wheel. Based on the target rotational speed of the outer rear wheel and the target rotational speed of the inner rear wheel, the outer rear motor and the inner rear motor are controlled respectively to cause the inner rear wheel to slip and generate a slipping force; and to enhance the driving force of the outer rear wheel.

4. The method according to claim 3, characterized in that, Determining the target speeds of the outer and inner rear wheels based on the theoretical speeds of the outer and inner rear wheels and the target yaw moment includes: Based on the first parameter of the vehicle, a matching first speed change is found in the first relationship; the first speed change is used to enhance the driving force of the outer rear wheel; the first relationship includes the speed change corresponding to different first parameters when the slip ratio meets the first range; Based on the theoretical speed of the outer rear wheel and the first speed change, the target speed of the outer rear wheel is determined; Based on the first parameter, a matching second rotational speed change is found in the second relationship; the second rotational speed change is used to generate slip force; the second relationship includes second rotational speed variables corresponding to different first parameters when the slip ratio meets the first range; The target speed of the inner rear wheel is determined based on the theoretical speed of the inner rear wheel and the second speed change.

5. The method according to claim 3, characterized in that, Based on the target speed of the outer rear wheel and the target speed of the inner rear wheel, the outer rear motor and the inner rear motor are controlled respectively to cause the inner rear wheel to slip and generate a slipping force. And enhance the driving force of the outer rear wheel, including: A proportional-integral-derivative (PID) control algorithm is used to control the output torque of the outer rear motor so that the output speed of the outer rear motor follows the target speed of the outer rear wheel, thereby enhancing the driving force of the outer rear wheel through the target speed of the outer rear wheel. A proportional-integral-derivative (PID) control algorithm is used to control the output torque of the inner rear motor so that the output speed of the inner rear motor follows the target speed of the inner rear wheel. The inner rear wheel slips due to the target speed of the inner rear wheel, generating a slip force.

6. The method according to claim 3, characterized in that, The method further includes: The target reduction in turning radius is determined based on the vehicle speed and steering wheel angle; different vehicle speeds and steering wheel angles correspond to different target reductions.

7. The method according to claim 1 or 2, characterized in that, When the target strategy is the second control strategy, the inner rear wheel is controlled to slip based on the target strategy, generating a slip force; And enhance the driving force of the outer rear wheel, including: The target rotational speed of the inner rear wheel is determined based on the target reduction in turning radius. Based on the target rotational speed of the inner rear wheel, the inner rear motor is controlled to cause the inner rear wheel to slip, generating a slipping force; Based on the target yaw moment and the actual moment of the inner rear wheel, the compensation moment of the outer rear wheel is determined; the target yaw moment is the compensation moment used to reduce the turning radius by the target reduction amount; Based on the compensation torque of the outer rear wheel and the basic torque of the outer rear wheel, the target torque of the outer rear wheel is determined. The outer rear motor is controlled based on the target torque of the outer rear wheel to enhance the driving force of the outer rear wheel.

8. The method according to claim 7, characterized in that, Determining the target rotational speed of the inner rear wheel based on the target reduction in turning radius includes: Determine the target slip ratio based on the target reduction in turning radius; Based on the target slip ratio and the theoretical speed of the inner rear wheel, the target speed of the inner rear wheel is determined; the theoretical speed is the speed of the wheel that does not slip when the vehicle is traveling at the current speed.

9. The method according to claim 1 or 2, characterized in that, When the target strategy is the third control strategy, the inner rear wheel is controlled to slip based on the target strategy, generating a slip force; And enhance the driving force of the outer rear wheel, including: Determine the target slip ratio based on the target reduction in turning radius; Based on the target slip ratio and the actual slip ratio, a proportional-integral-derivative (PID) control algorithm is used to control the output torque of the inner rear wheel, so that the actual slip ratio of the inner rear wheel follows the target slip ratio, and the inner rear wheel slips through the target slip ratio to generate slip force; Based on the target yaw moment and the actual moment of the inner rear wheel, the compensation moment of the outer rear wheel is determined; the target yaw moment is the compensation moment used to reduce the turning radius by the target reduction amount; Based on the compensation torque of the outer rear wheel and the basic torque of the outer rear wheel, the target torque of the outer rear wheel is determined. The outer rear motor is controlled based on the target torque of the outer rear wheel to enhance the driving force of the outer rear wheel.

10. A vehicle, characterized in that, The vehicle includes a controller for controlling the inner and outer rear wheels of the vehicle to implement the method according to any one of claims 1-9.

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