Vehicle control method, device and vehicle for reducing turning radius

Abstract

The application provides a vehicle control method and device for reducing a turning radius and a vehicle. The method comprises the following steps: acquiring a vehicle state parameter, and determining an initial target yaw angular velocity based on the vehicle state parameter; when an actual yaw angular velocity is greater than the initial target yaw angular velocity, the initial target yaw angular velocity is corrected; a yaw amplification coefficient is determined based on a wheel slip rate boundary, and the initial target yaw angular velocity is amplified based on the yaw amplification coefficient to obtain a final target yaw angular velocity; and a target yaw torque is determined based on the final target yaw angular velocity and the actual yaw angular velocity. The method ensures long-term accuracy and consistency of the turning radius control target through an online correction mechanism. The overall scheme does not need to increase additional hardware, and can be implemented only by relying on an existing linear control dynamic system, and has the advantages of low cost, wide application scene and easy mass production integration.

Description

Technical Field

[0001] This application belongs to the field of vehicle control, and more specifically, relates to a vehicle control method, device and vehicle for reducing turning radius. Background Technology

[0002] In the field of vehicle chassis control, existing technical solutions for reducing vehicle turning radius are mainly divided into three categories: The first category involves configuring an active rear-wheel steering mechanism. When the vehicle is turning or making a U-turn at low speed, the rear wheel steering angle is controlled to deflect in the opposite direction to the front wheel steering angle. The active steering of the rear wheels reduces the overall turning radius of the vehicle. However, this solution requires an additional rear-wheel steering actuator, which has high hardware costs and also restricts the overall vehicle layout space. The second category is suitable for distributed drive four-motor vehicles. By controlling the left and right wheels of the vehicle to rotate in opposite directions, an additional yaw moment is generated to achieve a turning effect on the spot. This solution relies on four-wheel independent drive hardware and can only be installed in electric vehicles with specific configurations, thus limiting its versatility. The third category uses EPB (Electrical Park Brake) to lock or brake the inner rear wheel with large slippage. The friction between the locked wheel and the ground generates an additional yaw moment, thereby reducing the turning radius. However, this solution may cause the braking wheel to slip continuously and cause severe tire wear.

[0003] In summary, existing solutions for reducing turning radius either rely on new hardware mechanisms and special power configurations, leading to increased costs, or reuse of parking brakes, resulting in tire wear and poor adaptability to operating conditions. Therefore, it is necessary to propose a vehicle control solution that does not rely on new hardware and is based on chassis domain control and brake-by-wire to reduce turning radius. Summary of the Invention

[0004] The purpose of this application is to provide a vehicle control method, device, and vehicle that reduces the turning radius based on chassis domain control and brake-by-wire without relying on additional hardware, so as to solve the technical problem in the related art that it is difficult to balance hardware cost and reducing turning radius.

[0005] To achieve the above objectives, the technical solution adopted in the embodiments of this application is as follows: Firstly, this application provides a vehicle control method for reducing turning radius, constructing a complete control closed loop from setting the target yaw rate to executing the target yaw moment, aiming to reduce the turning radius without increasing additional hardware costs. The method includes the following steps: S10: Obtain vehicle state parameters and determine the initial target yaw rate based on the vehicle state parameters; S20: Obtain the actual yaw rate of the vehicle; when the actual yaw rate is greater than the initial target yaw rate, correct the initial target yaw rate. S30: Determine the yaw rate amplification factor based on the wheel slip ratio boundary, and amplify the initial target yaw rate based on the yaw rate amplification factor to obtain the final target yaw rate; S40: Determine the target yaw moment based on the final target yaw rate and the actual yaw rate.

[0006] In one embodiment, step S20 includes: S21: Under the condition of satisfying the preset learning conditions, calculate the yaw deviation between the initial target yaw rate and the actual yaw rate; S22: When the yaw deviation is negative and the preset stability condition is met, the initial target yaw angular velocity is corrected using the yaw deviation.

[0007] In one embodiment, step S22 includes: S221: According to the formula The target yaw compensation angular velocity is obtained. ,in, The actual yaw rate, The initial target yaw rate; This is a preset adjustment coefficient, with a value range of [0,1]. S222: Perform first-order filtering on the target yaw compensation angular velocity to obtain the target yaw filtered angular velocity. ; S223: Calculate the ratio ; S224: Calculate the corrected difference , where, if the ratio If the ratio exceeds a preset upper limit threshold, then the ratio The value is set to a preset upper limit threshold. S225: Obtain the vehicle speed and steering wheel angle corresponding to the current actual yaw rate, and based on the difference... The two-dimensional lookup table value is corrected, and the two-dimensional lookup table value is used to calculate the initial target yaw rate in step S10.

[0008] In one embodiment, step S30 includes: S31: The lateral yaw amplification factor gradually increases from the initial value until the final target lateral yaw angular velocity is equal to the actual lateral yaw angular velocity. The lateral yaw amplification factor at this time is recorded as the minimum amplification factor. S32: Continue to increase the lateral alignment magnification factor until the slip ratio of each wheel reaches the preset slip limit, and record the lateral alignment magnification factor at this time as the maximum magnification factor; S33: Determine the horizontal magnification factor based on the minimum magnification factor and the maximum magnification factor.

[0009] In one embodiment, step S33 includes: According to the formula Calculate the horizontal placement coefficient. ; in, ; This is the minimum magnification factor. This refers to the maximum magnification factor; The preset weighting coefficient has a value range of [0,1].

[0010] In one embodiment, the method further includes: S50: During the execution of step S40, if the actual yaw rate exceeds the initial target yaw rate amplified based on the maximum amplification factor within a consecutive preset number of monitoring cycles, or if the rate of change of the actual yaw rate reaches a preset proportion of the initial target yaw rate amplified based on the maximum amplification factor, then exit and stop executing step S40.

[0011] In one embodiment, step S40 includes: S41: Construct the torque balance equation and longitudinal force balance equation that include the braking force of the inner wheel and the driving force of the outer wheel; S42: With the slip ratio of the inner wheel not exceeding a preset slip ratio threshold as a constraint, solve the torque balance equation and the longitudinal force balance equation to obtain the target braking force of the inner wheel and the target driving force of the outer wheel. S43: Control the inner wheel and the outer wheel based on the target braking force and the target driving force.

[0012] In one embodiment, step S42 includes: S421: For the inner front wheel and the inner rear wheel, closed-loop control is performed with the corresponding preset maximum allowable braking slip ratio as the target to obtain the target braking force of the inner front wheel and the target braking force of the inner rear wheel. S422: For the outer drive wheel, when calculating the target driving force, the drive slip ratio of the outer drive wheel is limited to not exceeding a preset drive slip ratio threshold.

[0013] Secondly, this application provides a vehicle turning radius control device, comprising: The data acquisition module is used to acquire the vehicle's actual yaw rate and vehicle state parameters; The target yaw determination module is used to determine the initial target yaw rate based on the vehicle state parameters, and to correct the initial target yaw rate based on the negative yaw deviation between the actual yaw rate and the initial target yaw rate. The lateral yaw rate module is used to determine the lateral yaw rate coefficient based on the wheel slip ratio boundary, and to amplify the initial target yaw rate based on the lateral yaw rate coefficient to obtain the final target yaw rate. The torque distribution module is used to determine the target yaw torque based on the final target yaw rate and the actual yaw rate.

[0014] Thirdly, this application provides a vehicle that includes the vehicle turning radius control device as described above.

[0015] Fourthly, this application provides a vehicle including a processor and a memory, the memory storing a computer program, and the processor executing the computer program to implement the vehicle control method for reducing turning radius as described in any of the preceding claims.

[0016] The vehicle control method, device, and vehicle for reducing turning radius provided in this application have at least the following beneficial effects: When there is a negative yaw deviation between the actual yaw rate and the initial target yaw rate, the long-term accuracy and consistency of the turning radius control target are ensured through an online correction mechanism; by dynamically learning the yaw enlargement coefficient based on the wheel slip ratio boundary, the control target is always adapted to the current road surface adhesion conditions, which not only fully taps the tire potential to reduce the turning radius, but also avoids the risk of instability caused by excessive target. The overall solution does not require additional hardware such as active rear wheel steering, and can be achieved solely by relying on the existing brake-by-wire system, which has the advantages of low cost, wide applicability, and easy mass production integration. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or exemplary technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic flowchart illustrating the vehicle control method for reducing turning radius provided in an embodiment of this application; Figure 2 This is a schematic diagram of the vehicle turning radius control device provided in the embodiments of this application; Figure 3This is a schematic diagram of the structure of a vehicle provided in an embodiment of this application. Detailed Implementation

[0019] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0020] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise expressly specified. "Several" means one or more, unless otherwise expressly specified.

[0021] Throughout this specification, references to "an embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of this application. Therefore, the phrases "in one embodiment" or "in some embodiments" appear in various places throughout the specification, and not all refer to the same embodiment. Furthermore, in one or more embodiments, particular features, structures, or characteristics may be combined in any suitable manner.

[0022] Vehicles can be of various types, including but not limited to pure electric vehicles (pure EV / battery EV), hybrid electric vehicles (HEV), range-extended electric vehicles (REEV), plug-in hybrid electric vehicles (PHEV), other new energy vehicles (NEV), or gasoline vehicles. These vehicles can be used in fields such as intelligent driving, assisted driving, or connected vehicles.

[0023] The turning radius can be understood as the distance from the outermost wheel of a vehicle to the steering center. The steering center refers to the instantaneous center where all parts and particles of the vehicle rotate around the same point with different radii of rotation; it is also called the instantaneous steering center.

[0024] Example 1 Please see Figure 1 This application provides a vehicle control method for reducing turning radius. This method constructs a complete control closed loop from setting the target yaw rate to executing the target yaw moment, aiming to reduce the turning radius without increasing additional hardware costs. Specifically, it includes the following steps: S10: Acquire vehicle state parameters and determine the initial target yaw rate based on the vehicle state parameters. Specifically, the vehicle state parameters include the current vehicle speed. Front wheel steering angle Total vehicle mass .

[0025] Specifically, the initial target yaw rate is a theoretically expected value calculated based on a vehicle dynamics model (such as a two-degree-of-freedom vehicle model or an Ackermann steering geometry model), representing the current front wheel steering angle. and vehicle speed The ideal cornering response characteristics that a vehicle should possess are as follows.

[0026] In one example, based on a two-degree-of-freedom vehicle model and linear lateral tire characteristics, the initial target yaw rate of the vehicle based on Ackerman geometry is obtained. formula: (1) (2) in, The characteristic vehicle speed value of a two-degree-of-freedom linear tire; For the front axle stiffness of the vehicle; Rear axle stiffness; This is the distance from the vehicle's center of gravity to the front axle. This is the distance from the vehicle's center of gravity to the rear axle. For the overall vehicle wheelbase, meet the requirements .

[0027] Specifically, the vehicle control method provided in this application is applied to low-speed, large-angle driving conditions, where the vehicle speed... The value ranges from 5 km / h to 15 km / h. Vehicle speed The rotational speeds of all four wheels can be collected by wheel speed sensors and fused using software algorithms. For example, wheel speed sensors can be installed on the wheels, such as on the wheel hub or the front brake disc, to collect the rotational speed information of that wheel. This speed information can be used to calculate the wheel speed, such as how many revolutions per minute (r / min), and then to calculate the vehicle speed, such as how many kilometers per hour (km / h) the vehicle travels forward or backward. (Front wheel steering angle) The value range is 22°-30°, front wheel steering angle The steering angle can be calculated by combining the steering wheel angle collected by the steering wheel angle sensor with the steering gear ratio. For example, the steering wheel angle sensor can be installed in the steering column below the steering wheel to collect the steering wheel's rotation information. This rotation information can be used to calculate the steering wheel angle, such as how many angles the steering wheel has rotated relative to its free state at the current moment. Alternatively, the steering wheel angle sensor can be replaced by a steering wheel position sensor, which can collect the steering wheel's position information. This position information can be used to calculate the steering wheel's rotation distance, with different rotation distances corresponding to different steering wheel angles.

[0028] Furthermore, characteristic vehicle speed value The calibration was performed on the actual vehicle, that is: (3) (4) (5) in, Based on vehicle speed Front wheel steering angle The input is the two-dimensional lookup table value; It is a one-dimensional lookup table value with the total vehicle mass m as input; , All results were obtained through actual vehicle calibration.

[0029] Two-dimensional table lookup The calibration range covers the front wheel steering angle range and speed range involved in this solution; for example, this solution is applied to low-speed, large-angle conditions, where the vehicle speed... The value range is 5km / h-15km / h, front wheel steering angle The value range is 22°-30°, while the two-dimensional lookup table... The calibration range includes a front wheel steering angle of 18°-35° and a speed of 2km / h-20km / h, covering the front wheel steering angle range and speed range involved in this solution.

[0030] It should be noted that, due to the initial target yaw rate This is the initial calibration quantity; the next step is to make adjustments based on the actual vehicle conditions to ensure the long-term accuracy of the target yaw rate.

[0031] S20: Obtain the actual yaw rate of the vehicle. When the actual yaw rate is greater than the initial target yaw rate, correct the initial target yaw rate.

[0032] Specifically, the actual yaw rate can be acquired in real time by an onboard inertial measurement unit (IMU) or a yaw rate sensor, without being limited to a single method. For example, the IMU can be positioned near the center point of the vehicle's coordinate system, such as within an airbag. An IMU typically includes three single-axis accelerometers and three single-axis gyroscopes. The three axes correspond to the three axes of the vehicle's coordinate system: the vehicle's travel direction (also known as longitudinal), pitch direction (also known as lateral), and yaw direction (also known as vertical). The three single-axis accelerometers can be used to collect acceleration information of the vehicle in the three axes of the vehicle's coordinate system. This acceleration information can be used to calculate the vehicle's acceleration in the three axes: longitudinal acceleration, lateral acceleration, and vertical acceleration. Longitudinal acceleration refers to the acceleration generated when the vehicle accelerates or decelerates along the travel direction; lateral acceleration refers to the lateral acceleration generated when the vehicle is turning; and vertical acceleration refers to the vertical acceleration generated when the vehicle is going up or down an incline. Three single-axis gyroscopes can be used to collect angular velocity information of the vehicle's rotation relative to the three axes of the navigation coordinate system. This angular velocity information can be used to calculate the vehicle's three angular velocities, namely roll rate, pitch rate, and yaw rate.

[0033] Since the purpose of this solution is to reduce the turning radius, the target yaw rate only needs to be increased to enhance the turning tendency when the vehicle's turning ability is insufficient. Therefore, correction is only made for negative yaw deviation. Negative yaw deviation, as referred to in this application, means that the actual yaw rate is less than the initial target yaw rate, i.e., the vehicle exhibits under-turning or an actual turning radius greater than theoretically expected. By using negative yaw deviation to compensate for and correct the initial target yaw rate, the steady-state error between the theoretical model and the actual vehicle characteristics can be effectively eliminated, making the corrected target yaw rate more closely match the vehicle's current real-world dynamic response.

[0034] S30: Determine the yaw rate amplification coefficient based on the wheel slip ratio boundary, and amplify the initial target yaw rate based on the yaw rate amplification coefficient to obtain the final target yaw rate.

[0035] Specifically, the purpose of the yaw rate amplification factor is to multiply the initial target yaw rate, virtually increasing the steering wheel angle without altering the mechanical steering mechanism, thereby further stimulating the vehicle's turning potential. The wheel slip ratio boundary referred to in this application refers to the slip ratio limit value at which each wheel can maintain stable driving without excessive slippage or lock-up under current road surface adhesion conditions. If the yaw rate amplification factor is too small, the turning radius reduction effect is not significant; if the yaw rate amplification factor is too large, it will lead to excessive wheel slip ratio and instability. Therefore, by amplifying the initial target yaw rate through this yaw rate amplification factor, the tire adhesion potential is fully utilized to achieve a significant turning radius reduction effect, while ensuring that the control target remains within the vehicle's dynamic stability domain.

[0036] S40: Determine the target yaw moment based on the final target yaw rate and the actual yaw rate.

[0037] Specifically, the final target yaw rate, after correction and amplification, is used as the setpoint for closed-loop control, while the actual yaw rate is used as the feedback value. The deviation between the two is calculated by a controller (such as a PID controller or a model predictive controller), thereby generating a target yaw moment to drive the vehicle to track the target. This target yaw moment is then distributed to the braking and drive systems of each wheel. Additional yaw moments are generated by applying braking force to the inner wheels and driving force to the outer wheels, forcing the vehicle's actual trajectory to approach the final target yaw rate.

[0038] Thus, through the processes described in steps S10 to S40, this embodiment constructs a progressively layered control architecture: S10 provides a theoretical benchmark, S20 eliminates model errors and ensures the correct optimization direction through negative bias learning, S30 establishes a safe and feasible performance upper limit through slip ratio boundary constraints, and S40 achieves precise tracking through closed-loop torque control. This vehicle control method not only effectively reduces the turning radius but, more importantly, maximizes control benefits while ensuring safety boundaries. It also avoids the longitudinal impact and instability problems common in traditional methods, achieving a comprehensive balance between performance, comfort, and safety.

[0039] It should be noted that the correction in step S20 is only performed when a negative yaw deviation exists, and is not performed every time the vehicle control method is activated. In other words, under low-speed, large-angle conditions, when this control method is activated, the specific process is that S10, S30, and S40 are executed sequentially, and step S20 is executed conditionally.

[0040] In some embodiments, step S20 includes the following steps: S21: Under the condition of meeting the preset learning conditions, calculate the yaw deviation between the initial target yaw rate and the actual yaw rate.

[0041] Specifically, the preset learning conditions include: the vehicle being powered on or off for a specific time period (e.g., 10 seconds to 1 minute), or the detection of a door opening operation. Furthermore, when this solution is applied to low-speed, large-angle turning conditions, the preset learning conditions also need to simultaneously meet the current vehicle speed. Below the preset low speed threshold (e.g., 15 km / h), and the front wheel angle The angle is greater than a preset large turning angle threshold (e.g., 20°). It should be understood that the above conditions are only examples, and in other implementations, other constraints such as lateral acceleration range limits may be added according to vehicle type or control strategy requirements.

[0042] S22: When the yaw deviation is negative and the preset stability condition is met, the initial target yaw angular velocity is corrected using the yaw deviation. Based on this, after confirming that the yaw deviation is negative, it is also necessary to determine whether it meets the preset stability condition to eliminate the influence of sensor noise or instantaneous road surface disturbances.

[0043] Specifically, once the aforementioned preset learning conditions are met, the system does not immediately recognize the negative yaw deviation. Instead, it requires the preset control period (TBD) to be continuously met to ensure that the collected data has sufficient statistical stability. Optionally, the preset control period can range from 5ms to 20ms, and the specific value can be calibrated based on the sensor sampling rate and the controller's computing power. Only when the learning conditions are consistently met within the preset control period can the current operating condition be considered valid, thus proceeding to the deviation calculation and judgment stage.

[0044] Furthermore, the preset stability conditions include: the negative yaw deviation is less than a first design threshold, and the root mean square error of the negative yaw deviation within a preset time window (e.g., 80ms to 200ms) is less than a second design threshold. The first design threshold is a calibrated negative threshold (e.g., -0.5deg / s) used to filter out small, uncorrectable steady-state errors; the second design threshold measures the degree of signal fluctuation, and is considered to reflect true model mismatch rather than random interference only when the deviation signal is sufficiently stable.

[0045] In one possible example, step S22 includes the following sub-steps: S221: According to the formula The target yaw compensation angular velocity is obtained. .in, This is the actual yaw rate. The initial target yaw rate, This is a preset adjustment coefficient, with a value range of [0, 1]. Essentially, it controls the step size or gain of a single learning iteration: when When the value is close to 1, the correction speed is fast but may cause oscillations; when... When the value is close to 0, the correction process is smooth but the convergence time is long. Specifically, in actual calibration, an appropriate value (such as 0.3-0.7) can be selected based on the sensitivity of the vehicle's dynamic response to balance learning efficiency and stability.

[0046] S222: Perform first-order filtering on the target yaw compensation angular velocity to obtain the target yaw filtered angular velocity. Even after stability screening, the original deviation signal may still contain high-frequency components, and directly using it for correction may cause frequent jumps in the lookup table value. First-order low-pass filtering can effectively smooth the correction amount, prevent sawtooth fluctuations in the underlying calibration data, and ensure the continuity of the control output.

[0047] S223: Calculate the ratio .ratio Normalizing the absolute correction amount facilitates unified security boundary control in the future.

[0048] S224: Calculate the corrected difference , where, if the ratio If the ratio exceeds the preset upper limit threshold, then The value is set to a preset upper threshold. This preset upper threshold (e.g., 1.5) acts as a safety valve to prevent overcorrection. Even if the learning algorithm calculates a large compensation amount, this method will forcibly limit it to a reasonable range, preventing the target yaw from being excessively amplified due to a single abnormal data point, thus exceeding the vehicle's physical limits. The corrected difference... This reflects the residual deviation that still needs to be eliminated between the final target yaw rate and the actual yaw rate under the current safety constraints.

[0049] S225: Obtain the vehicle speed and front wheel steering angle corresponding to the current actual yaw rate, and based on the difference... The two-dimensional lookup table value is corrected and used in step S10 to calculate the initial target yaw rate. Specifically, the two-dimensional lookup table is as described above. It should be noted that the two-dimensional lookup table value corrected in step S225 is used in step S10 when the function of this method is activated again.

[0050] Traditional adaptive control often simply adds a compensation variable to the final output, and the compensation effect disappears once the operating conditions change or the system restarts. This application, however, uses the difference... Mapping back to basic feature parameters (such as the vehicle speed value in a two-degree-of-freedom model) The underlying calibration data is updated directly through a lookup table. Specifically, this is done based on the current vehicle speed. and front wheel cornering Locate the corresponding grid point in the lookup table and use the difference. Regarding this point The values ​​are fine-tuned. As the vehicle is repeatedly driven under different operating conditions, the entire calibration table will be iteratively optimized step by step, so that the calculation accuracy of the initial target yaw rate will continuously improve over time. This correction strategy not only ensures long-term control accuracy, but also enables the vehicle to adapt to slow time-varying characteristics such as tire wear and load changes, achieving true adaptive evolution.

[0051] In some embodiments, step S30 includes the following steps: S31: The yaw magnification factor gradually increases from its initial value until the final target yaw rate equals the actual yaw rate. This final yaw magnification factor is recorded as the minimum magnification factor. Minimum magnification factor. This characterizes the minimum gain level at which the vehicle dynamics system can track the target yaw rate without deviation under the current operating conditions. When the yaw gain factor equals... This means that the amplified final target yaw rate is exactly equal to the vehicle's current actual yaw rate. Any amplification factor lower than this value will result in the final target yaw rate being less than the actual yaw rate, failing to achieve the intended function of reducing the turning radius. Therefore, This constitutes the lower limit of the effectiveness of the control strategy, ensuring that the set goals are physically achievable and avoiding functional failure or delayed response due to overly low goals.

[0052] Specifically, the initial value of the horizontally placed large coefficient is greater than or equal to 1. Specifically, for different vehicle speeds... Front wheel steering angle Combinations yield different minimum magnification factors. Forming a set of minimum values .

[0053] S32: Continue increasing the lateral alignment magnification factor until the slip ratio of each wheel reaches the preset slip limit. Record the lateral alignment magnification factor at this point as the maximum magnification factor. Maximum magnification factor This characterizes the upper limit of the safe gain allowed by tire adhesion conditions. As the yaw rate factor increases, the additional yaw moment requested by the vehicle control system increases accordingly, and the braking slip ratio of the inner wheel and the driving slip ratio of the outer wheel also increase accordingly. When the yaw rate factor increases to a certain critical value, causing the slip ratio of any wheel to reach a preset slip limit (e.g., braking slip ratio reaching 15%-20%, or driving slip ratio reaching 10%-15%), it indicates that the tire is approaching the adhesion saturation zone. Further increasing the gain will easily lead to wheel lock-up, excessive slippage, or even vehicle instability. Therefore, This constitutes the safety boundary of the control strategy, ensuring that the vehicle's stability remains within a controllable range even when pursuing extremely small-radius turns.

[0054] For different vehicle speeds Front wheel steering angle Combinations yield different maximum magnification factors , forming the maximum value set .

[0055] S33: Based on minimum magnification factor and maximum magnification factor Determine the coefficient for horizontal placement. Specifically, in practical applications, the aforementioned minimum magnification factor... and maximum magnification factor The learning process typically involves calibration or online detection on high-adhesion road surfaces to establish the most basic safety benchmarks.

[0056] It should be understood that although this embodiment uses a high-adhesion road surface as an example for illustration, in other embodiments, corresponding methods can be established for road surfaces with different adhesion coefficients. and Look up tables or adjust boundary values ​​in real time through road surface recognition algorithms to adapt to more complex driving environments.

[0057] Step S33 specifically involves obtaining the minimum magnification factor. and maximum magnification factor Then, the final horizontal alignment coefficient is determined by weighted interpolation. Specifically, according to the formula Calculate the coefficient for horizontal placement. ;in, ; The preset weighting coefficient has a value range of [0,1].

[0058] when When the value is large (e.g., close to 1), the calculated value is... More inclined to This means the system has chosen a more conservative control strategy, prioritizing smoothness and comfort, with a relatively gentle reduction in turning radius, suitable for daily driving or scenarios where comfort is a high priority; conversely, when When the value is small (e.g., close to 0), More inclined to The system will make full use of the tire's grip potential to achieve the maximum reduction in turning radius, bringing a more agile and sharp handling experience, suitable for U-turns in tight spaces or sport driving mode.

[0059] As a preferred implementation method, a preset weighting coefficient is used. The typical calibration range can be set to 0.3 to 0.7. Within this range, the system can achieve a good overall balance between safety, comfort, and maneuverability. Furthermore, this weighting coefficient does not necessarily have to be a fixed value; it can be dynamically adjusted based on the driver's selected driving mode or real-time monitored driving intentions. For example, in "Comfort Mode," the system can... It automatically adjusts to 0.6-0.7; however, in "Sport Mode" or when a rapid, large-angle steering intention by the driver is detected, it can be adjusted. The dynamic range is reduced to 0.3-0.4, thereby giving the vehicle a differentiated handling character without changing the underlying safety boundaries.

[0060] Furthermore, the formula explicitly specifies... The constraint condition. This constraint has important functional guiding significance: since the core objective of this application is to reduce the turning radius, it is required that the final target yaw rate is at least not less than the initial target yaw rate. If the calculated A value less than 1 means that the magnified target is actually shrunk, which not only violates the original design intent but may also lead to unexpected understeer during vehicle cornering. Therefore, regardless of how the weighting coefficient changes or how the boundary value fluctuates, the system must perform mandatory verification during execution to ensure that the lateral magnification coefficient is not less than 1, thereby guaranteeing the certainty and consistency of the function intervention direction.

[0061] Furthermore, considering the complexity of actual driving environments, even under the aforementioned slip ratio constraints, vehicles may still face instability risks on low-adhesion surfaces, separated surfaces, or other unmodeled dynamic conditions. Therefore, this embodiment also includes an independent safety monitoring and exit mechanism. The vehicle control method further includes the following steps: S50: If the actual yaw rate exceeds the maximum amplification factor within a preset number of consecutive monitoring cycles... The magnified initial target yaw rate, or, if the rate of change of the actual yaw rate reaches the maximum magnification factor. If the preset ratio of the magnified initial target yaw rate is used, then exit the stop execution step S40.

[0062] This safety monitoring mechanism includes two complementary triggering conditions, each targeting a different type of instability mode. The first condition is an absolute over-limit sustained judgment, which occurs when the actual yaw response has significantly exceeded the system's maximum safety boundary (determined by the maximum amplification factor). The first condition is the definition of yaw rate. Exit is triggered only when this over-limit state persists for a preset number of monitoring cycles. The preset number of monitoring cycles can range from 3 to 5 (e.g., 30ms to 50ms per monitoring cycle). This time window is designed to filter out brief signal spikes caused by sensor noise or instantaneous road disturbances, preventing erroneous function exit, while also allowing timely intervention to be cut off when a sustained oversteering or loss of control trend is confirmed. The second condition is the abnormal rate of change judgment, i.e., when the rate of change of the actual yaw rate (or the filtered derivative) reaches a preset proportion of the initial target yaw rate amplified by a preset amplification factor, exit is triggered immediately. The preset proportion can be calibrated from 80% to 120%, and its physical meaning is to monitor the severity of the vehicle's yaw response. Even if the absolute value of the actual yaw rate has not exceeded the limit, if its rate of change is extremely fast, it indicates that the vehicle is on the verge of abrupt instability (such as a sudden fishtail on ice). In this case, the system must exit directly regardless of the duration, returning control to the driver or the underlying electronic stability control system. These two conditions together constitute the last line of defense against accidental triggering or excessive intervention of the function, ensuring the safety baseline of the reduced turning radius function under any extreme operating conditions.

[0063] According to formula (1), the yaw rate of the Ackerman target is related to the front wheel rotation angle. The wheelbase L is related to the front wheel steering angle. The yaw rate is linearly related to the target's yaw rate; therefore, a yaw rate amplification factor is used to amplify the yaw rate of the Ackerman target, effectively increasing the front wheel steering angle. The control effect is achieved by fusing the amplified yaw rate request with the target yaw rate requests output by other vehicle control functions and taking the maximum value to obtain the final target yaw rate. The software assignment statement is used:

[0064] in, If the target yaw request comes from other functions in the previous control cycle, and there are no other yaw request inputs. Take 0. Update the output value for this period.

[0065] In some embodiments, step S40 specifically includes the following steps: S41: Construct the torque balance equation and longitudinal force balance equation that include the braking force of the inner wheel and the driving force of the outer wheel.

[0066] S42: With the slip ratio of the inner wheel not exceeding the preset slip ratio threshold as a constraint, solve the torque balance equation and the longitudinal force balance equation to obtain the target braking force of the inner wheel and the target driving force of the outer wheel.

[0067] S43: Control the inner and outer wheels based on the target braking force and target driving force.

[0068] In traditional differential braking or torque vectoring control, to generate additional yaw moment, braking force is often applied to the inner wheel and driving force to the outer wheel. However, this asymmetrical torque application inevitably generates a resultant force component in the vehicle's longitudinal direction, leading to unexpected deceleration or acceleration during cornering, known as "longitudinal jerking," which severely affects driving comfort. To address this issue, this embodiment introduces a longitudinal force balance equation as a core constraint. Specifically, the torque balance equation ensures that the sum of the yaw moments around the center of mass generated by the inner braking force and the outer driving force equals the target yaw moment determined in step S40; while the longitudinal force balance equation mandates that the longitudinal component of the inner wheel braking force and the longitudinal component of the outer wheel driving force are equal in magnitude and opposite in direction, thus canceling each other out in the longitudinal direction. By solving these two sets of equations simultaneously, the system can accurately track the target yaw moment while eliminating the net output of longitudinal force in principle. This ensures that the driver only feels the reduction in turning radius when the function intervenes, without perceiving any obvious longitudinal acceleration or deceleration impact, thus significantly improving the smoothness and concealment of the function intervention.

[0069] Furthermore, to ensure the safety of torque distribution, this embodiment employs a differentiated slip ratio management strategy for the inner and outer wheels.

[0070] In one example, step S42 includes the following steps: S421: For the inner front wheel and the inner rear wheel, closed-loop control is performed with the corresponding preset maximum allowable braking slip ratio as the target to obtain the target braking force of the inner front wheel and the target braking force of the inner rear wheel.

[0071] In one example, step S42 includes the following step: S422: For the outer drive wheel, when calculating the target driving force, the drive slip ratio of the outer drive wheel is limited to not exceeding a preset drive slip ratio threshold.

[0072] It should be understood that the main function of the inner wheel is to provide braking force to generate yaw moment, while simultaneously using the braking slip ratio to adjust the tire's lateral characteristics. The preset maximum permissible braking slip ratio is typically calibrated near the optimal operating point on the tire's adhesion ellipse (e.g., 15% to 20%). At this slip ratio, the tire can simultaneously provide significant longitudinal braking force and sufficient lateral support, avoiding insufficient yaw moment due to a slip ratio that is too low, or wheel lock-up and loss of lateral stability due to a slip ratio that is too high. Therefore, employing independent closed-loop control (such as PID control) for the inner front and inner rear wheels, ensuring their actual braking slip ratio accurately tracks this preset target value, is crucial for achieving efficient and stable turning radius control. In contrast, the main function of the outer wheel is to provide driving force to balance longitudinal forces and assist in generating yaw moment. An excessively high driving slip ratio can directly lead to a sharp decrease in tire lateral adhesion, increasing the risk of the vehicle understeer or fishtailing. Therefore, a limit protection strategy is adopted for the outer drive wheel, that is, its drive slip ratio is monitored in real time. Once it approaches or exceeds the preset drive slip ratio threshold (e.g., 8% to 12%), the target drive force is immediately reduced or clamped to ensure that the outer wheel is always in the linear adhesion zone and maintain the lateral dynamic stability of the vehicle.

[0073] In a specific example, the final target yaw rate YawrateTar is constructed using the actual yaw rate measured by the IMU. The closed-loop feedback controller serves as the input; in this embodiment, it employs a PID controller, and the output target is the additional yaw moment request MzTar. In other embodiments, the closed-loop feedback controller may also employ a model predictive controller (MPC).

[0074] To achieve the target additional yaw moment request MzTar, an additional yaw moment is generated by applying braking force to the inner wheels and driving force to the outer wheels. Simultaneously, to minimize the driver's perception of the function intervention, the braking force and driving force need to maintain a balance of longitudinal forces throughout the vehicle, avoiding significant acceleration and deceleration shocks. The four control variables to be solved are: the target braking force request FbfiTar for the inner front wheels, the target braking force request FbriTar for the inner rear wheels, the target driving force request FdfoTar for the outer front wheels, and the target driving force request FdroTar for the outer rear wheels.

[0075] Establish the yaw moment equilibrium equation:

[0076] Establish the equilibrium equation for longitudinal forces:

[0077] Where b is the wheel track and L is the vehicle wheelbase.

[0078] To prevent excessive slippage of the inner wheels during braking, slip ratio closed-loop control constraints are set for both the inner rear and inner front wheels. For the inner rear wheel, the maximum allowable slip ratio under this functional scenario is obtained through actual vehicle calibration and used as the target slip ratio for the inner rear wheel. The actual wheel speed of the inner rear wheel is obtained, and a PID closed-loop controller is used to obtain the target braking force FbriTar for the inner rear wheel. For the inner front wheel, the maximum allowable slip ratio under this functional scenario is obtained through actual vehicle calibration as the target slip ratio for the inner front wheel. The actual wheel speed of the inner front wheel is obtained, and a PID closed-loop controller is used to obtain the target braking force of the inner front wheel. .

[0079] Drive slip protection for the outer drive wheels: The wheel slip ratio of the outer front wheel and the outer rear wheel is monitored in real time. The drive force output must not exceed the design threshold of wheel slip ratio. Once the slip ratio of the outer drive wheel exceeds the threshold, the drive force output is limited.

[0080] In this embodiment, the wheel slip ratio is defined as: In the formula, The wheel speed is calculated from the wheel rotation speed. This is the reference speed at the point where the wheel touches the ground, i.e., the actual speed of the vehicle.

[0081] Example 2 To more intuitively demonstrate the collaborative working effect of the vehicle control methods for reducing turning radius in the aforementioned embodiments under actual working conditions, this embodiment provides a full-link application example in a low-speed, large-angle U-turn scenario. It should be understood that the specific parameters and scenarios below are merely illustrative and not intended to limit the scope of protection of this application. In other embodiments, the above parameters can be adaptively adjusted according to vehicle dynamics characteristics and calibration strategies.

[0082] In this application scenario, the vehicle is positioned on a dry asphalt road at a current speed of 8 km / h. The driver inputs a steering wheel angle of 25°. The system determines that the function activation condition is met and enters the turning radius reduction control mode, i.e., it activates the vehicle control method. During the target determination phase, the system first obtains the corresponding characteristic speed K value by querying a pre-calibrated characteristic parameter calibration table based on the current vehicle speed of 8 km / h and the steering wheel angle of 25° (equivalent to the front wheel angle in this embodiment), and then calculates the initial target yaw rate. Since this initial value is based on a theoretical model and may differ from the actual response of the vehicle due to tire wear or changes in the vehicle's total mass, the system then enters an online monitoring state.

[0083] During control execution, the onboard inertial measurement unit (IMU) collects the vehicle's actual yaw rate in real time. Comparison reveals that the actual value is 0.5 deg / s lower than the initial target yaw rate, resulting in a negative yaw deviation of -0.5 deg / s. Since this deviation is negative and consistently meets the preset learning and stability conditions, the system automatically triggers an adaptive correction mechanism. Specifically, the system uses this negative deviation to fine-tune and update the K value in the feature parameter lookup table, ensuring that the subsequently calculated initial target yaw rate can compensate for this steady-state error. This guarantees that the control target always points in the direction that reduces the turning radius, avoiding functional degradation due to model mismatch.

[0084] After determining the initial target yaw rate, the yaw maximization module dynamically determines the yaw maximization coefficient based on the current wheel slip ratio boundary. In this scenario, the system, through online detection, determines that the minimum amplification coefficient μ_min is 1.2 and the maximum amplification coefficient μ_max is 1.5 under the current operating conditions. To balance the reduction of turning radius with driving stability, the system performs weighted interpolation calculations based on a preset weight coefficient c (e.g., a value of 0.5), ultimately determining the yaw maximization coefficient μ to be 1.35. This value is higher than the lower limit of 1.2 for ensuring target accessibility and lower than the upper limit of 1.5 for reaching the tire adhesion limit, indicating that the system has chosen a moderately aggressive control strategy under the current road conditions, maximizing the vehicle's turning potential within the safe domain.

[0085] During the torque distribution and execution phase, the system calculates the required target yaw torque based on the deviation between the final target yaw rate (amplified by μ=1.35) and the actual yaw rate. This torque is then distributed to the four wheels by simultaneously solving the torque balance equation and the longitudinal force balance equation. During execution, for the inner rear wheel, the system uses closed-loop control to precisely maintain its braking slip ratio at approximately 15%, a calibrated optimal braking efficiency point that provides sufficient yaw torque without causing wheel lock-up. For the outer front wheel, the system monitors its drive slip ratio in real time and strictly limits it to below 10% to prevent lateral instability caused by excessive driving force. Simultaneously, thanks to the constraints of the longitudinal force balance equation, the resultant force components generated longitudinally by the inner braking force and the outer driving force cancel each other out. Throughout the intervention process, the longitudinal acceleration fluctuation of the vehicle is controlled within 0.02g, making it virtually imperceptible to the driver to any noticeable longitudinal jerking or impact, ensuring smoothness and comfort during function intervention.

[0086] Furthermore, the safety monitoring module continuously assesses the vehicle's status throughout the entire control cycle. Since the actual yaw rate remained within the envelope of the target yaw rate amplified by the maximum amplification factor μ_max, and the rate of change was stable, the system did not trigger any safety exit conditions throughout the entire process, verifying the robustness and safety of this control strategy under typical dry road surface large turning angle conditions.

[0087] Example 3 Combination Figure 2 This embodiment provides a vehicle turning radius control device, including a data acquisition module 11, a target yaw determination module 12, a yaw maximization module 13, and a torque distribution module 14.

[0088] The data acquisition module 11 is used to acquire the vehicle's actual yaw rate and vehicle state parameters. Specifically, this module serves as the sensing input interface for the entire control system, responsible for real-time acquisition and preprocessing of vehicle dynamics signals. The actual yaw rate is typically obtained from the onboard inertial measurement unit or yaw rate sensor, while the vehicle state parameters include, but are not limited to, vehicle speed, front wheel steering angle, and total vehicle mass.

[0089] In one implementation, the data acquisition module 11 may further include a signal filtering and validity verification subunit, used to eliminate sensor noise and abnormal jump values, ensuring that the subsequent control module receives high-confidence status data. It should be understood that although this embodiment classifies the data acquisition function as an independent module, in actual engineering implementation, the function of this module can also be directly undertaken by the underlying driver software of the chassis domain controller, as long as it can provide a standardized data interface to subsequent modules.

[0090] The target yaw determination module 12 is used to determine the initial target yaw rate based on vehicle state parameters, and to correct the initial target yaw rate based on the negative yaw deviation between the actual yaw rate and the initial target yaw rate.

[0091] Specifically, the target yaw determination module 12 integrates a basic target calculation unit and an adaptive correction unit. The basic target calculation unit calculates the theoretical initial target yaw rate based on vehicle state parameters through table lookup or model calculation; the adaptive correction unit continuously monitors the deviation between the actual yaw response and the initial target, triggering a correction mechanism only when a negative yaw deviation is detected and preset learning conditions are met, updating internally stored feature parameters or directly outputting the compensated target value. This modular design allows the target generation logic to iterate independently. For example, without changing other modules, the adaptive correction unit can implement steps S221-S225 above, independently upgrading the correction algorithm or updating the calibration table, thereby continuously improving the turning radius control accuracy of the vehicle during long-term use.

[0092] The yaw rate amplification module 13 is used to determine the yaw rate amplification coefficient based on the wheel slip ratio boundary, and amplify the initial target yaw rate based on the yaw rate amplification coefficient to obtain the final target yaw rate. Specifically, the yaw rate amplification module 13 contains slip ratio boundary detection logic and a coefficient weighting calculation unit. It receives wheel slip ratio information from the data acquisition module and the initial target yaw rate from the target yaw rate determination module, obtains the minimum and maximum amplification coefficients under the current operating conditions through online detection or table lookup, and calculates the final yaw rate amplification coefficient according to a preset weighting strategy. The core function of this module is to maximize the turning potential of the vehicle while ensuring safety. The final target yaw rate output reflects the driver's steering intention and is subject to the physical constraints of tire adhesion limits, avoiding the risk of instability caused by overly aggressive target settings.

[0093] The torque distribution module 14 determines the target yaw moment based on the final target yaw rate and the actual yaw rate. Specifically, the torque distribution module 14 is the execution decision center for control commands. Internally, it contains solvers for torque balance equations and longitudinal force balance equations, and integrates an inner wheel brake slip ratio closed-loop controller and an outer wheel drive slip ratio limit protector. This module receives the final target yaw rate as a setpoint, combines it with actual yaw rate feedback, calculates the four-wheel target torque request that satisfies longitudinal force balance and is constrained by slip ratio, and converts it into specific braking pressure and drive torque commands, which are then sent to the actuators. By encapsulating all torque distribution strategies within this module, a deep integration of comfort control and safety control is achieved, ensuring smoothness and stability during function intervention.

[0094] The aforementioned modules interact with each other via an internal bus or shared memory, forming a complete closed loop from perception to decision-making to execution. As a preferred implementation, this vehicle turning radius control device can be integrated into the vehicle's chassis domain controller as a software program, utilizing the domain controller's high computing power to perform complex real-time calculations. Furthermore, due to its modular architecture, the interfaces between modules are clearly defined, facilitating portability and adaptation across different vehicle platforms. It also supports independent algorithm upgrades or parameter optimizations for specific modules via OTA (Over-the-Air) technology, thereby endowing the vehicle with the ability to evolve performance throughout its entire lifecycle.

[0095] The aforementioned vehicle turning radius control device can be a device specifically designed to implement steering control, or it can be a device that implements steering control while also performing other functions. For example, in one example, the vehicle turning radius control device can be a control unit within the vehicle, such as a vehicle control unit (VCU), vehicle dynamics control (VDC), or mobile data center (MDC), or it can be a domain controller, such as a driving domain controller or chassis domain controller. Using this example, the steering control function can be implemented using the control unit already present in the vehicle, improving the utilization rate of in-vehicle components.

[0096] It should be understood that although this embodiment describes four independent functional modules, in other embodiments, two or more of these modules may be merged into one processing unit according to hardware resources or real-time requirements, or a module may be split into multiple sub-modules. As long as the whole can achieve the aforementioned control logic and functional effects, it shall fall within the protection scope of this application.

[0097] Example 4 This embodiment provides a vehicle including a vehicle turning radius control device as described in Embodiment 3. In this implementation, the vehicle turning radius control device is typically integrated as a software module or firmware into the vehicle's chassis domain controller, vehicle controller, or dedicated brake-by-wire controller. For example, the device can operate as an independent functional partition within the chassis domain controller, directly accessing underlying sensor data and sending control commands to the brake actuators. This integration method fully utilizes the computing resources of existing onboard computing platforms without requiring additional independent hardware control units, thus reducing overall vehicle material costs and layout complexity.

[0098] It should be understood that although the chassis domain controller is used as an example here, in other embodiments, the device can also be distributed among multiple communicating electronic control units, as long as the units work together to achieve the functions of the aforementioned device.

[0099] Example 5 Combination Figure 3This embodiment provides a vehicle including a processor 21 and a memory 22. The memory 22 stores a computer program 23. When the processor 21 executes the computer program 23, it implements the vehicle control method for reducing the turning radius as described in any of the embodiments above. In this embodiment, the processor 21 can be any computing chip with data processing capabilities, such as a microcontroller unit, a system-on-a-chip, a field-programmable gate array, or an application-specific integrated circuit. The memory 22 can include a read-only memory, a random access memory, flash memory, or a disk storage device, etc., for persistent or temporary storage of program code and data. When the processor 21 reads and executes the computer program 23 in the memory 22, it drives the hardware resources to complete the entire process of control actions, from acquiring vehicle state parameters, determining and correcting the target yaw rate, calculating the yaw rate maximization factor, to the final torque distribution. Based on this, the above vehicle control method can be adapted to different on-board computing platforms, whether it is a centralized electronic and electrical architecture or a traditional distributed architecture.

[0100] For example, the computer program 23 may be divided into one or more units, which are stored in the memory 22 and executed by the processor 21 to complete the present application. The one or more units may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program 23 in a vehicle.

[0101] Example 6 This application also provides a computer-readable storage medium. The computer-readable storage medium stores a computer program, which, when executed by a processor, implements any of the vehicle control methods described in Embodiment 1. Since the instructions stored in the computer-readable storage medium can execute the steps of any of the vehicle control methods provided in the embodiments of this application, the beneficial effects achievable by any of the vehicle control methods provided in the embodiments of this application can be realized, as detailed in the preceding embodiments, and will not be repeated here.

[0102] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be performed by instructions, or by instructions controlling related hardware. These instructions can be stored in a computer-readable storage medium and loaded and executed by a processor.

[0103] The computer-readable storage medium may include: read-only memory (ROM), random access memory (RAM), disk or optical disk, etc.

[0104] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0105] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0106] In the embodiments provided in this application, it should be understood that the disclosed apparatus / terminal devices and methods can be implemented in other ways. For example, the apparatus / terminal device embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0107] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0108] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0109] If an integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer-readable medium may include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0110] Furthermore, the vehicles provided in this embodiment not only cover various power configurations such as traditional fuel vehicles, hybrid vehicles, and pure electric vehicles, but are also particularly suitable for intelligent connected vehicles equipped with wired braking systems. Since the control method of this application mainly relies on the precise torque response of the braking and drive systems, the millisecond-level pressure regulation capability provided by the wired braking system enables the vehicle to achieve a more refined and smooth turning radius control experience. In addition, given the software-defined nature of the control logic, the vehicle also supports remote updates of calibration parameters stored in the memory or within the device via over-the-air (OTA) download technology. This allows for continuous optimization of turning radius control performance or adaptation to new tire characteristics even after the vehicle is sold, giving the product the ability to evolve performance throughout its entire lifecycle.

[0111] Through the implementation at the product level, this application solidifies the aforementioned control method into the standard functional configuration of the vehicle. Without adding expensive mechanical components such as an active rear-wheel steering mechanism, it significantly improves the vehicle's maneuverability in low-speed and narrow scenarios, while ensuring driving comfort and safety when the function intervenes, effectively enhancing the market competitiveness and user satisfaction of the entire vehicle product.

[0112] It should be understood that the sequence number of each step in the above embodiments does not imply the 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.

[0113] The above are merely optional embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A vehicle control method for reducing turning radius, characterized in that, Includes the following steps: S10: Obtain vehicle state parameters and determine the initial target yaw rate based on the vehicle state parameters; S20: Obtain the actual yaw rate of the vehicle; when the actual yaw rate is greater than the initial target yaw rate, correct the initial target yaw rate. S30: Determine the yaw rate amplification factor based on the wheel slip ratio boundary, and amplify the initial target yaw rate based on the yaw rate amplification factor to obtain the final target yaw rate; S40: Determine the target yaw moment based on the final target yaw rate and the actual yaw rate.

2. The vehicle control method for reducing turning radius according to claim 1, characterized in that, Step S20 includes: S21: Under the condition of satisfying the preset learning conditions, calculate the yaw deviation between the initial target yaw rate and the actual yaw rate; S22: When the yaw deviation is negative and the preset stability condition is met, the initial target yaw angular velocity is corrected using the yaw deviation.

3. The vehicle control method for reducing turning radius according to claim 2, characterized in that, Step S22 includes: S221: According to the formula The target yaw compensation angular velocity is obtained. ,in, The actual yaw rate, The initial target yaw rate; This is a preset adjustment coefficient, with a value range of [0,1]. S222: Perform first-order filtering on the target yaw compensation angular velocity to obtain the target yaw filtered angular velocity. ; S223: Calculate the ratio ; S224: Calculate the corrected difference , where, if the ratio If the ratio exceeds a preset upper limit threshold, then the ratio The value is set to a preset upper limit threshold. S225: Obtain the vehicle speed and steering wheel angle corresponding to the current actual yaw rate, and based on the difference... The two-dimensional lookup table value is corrected, and the two-dimensional lookup table value is used to calculate the initial target yaw rate in step S10.

4. The vehicle control method for reducing turning radius according to claim 1, characterized in that, Step S30 includes: S31: The lateral yaw amplification factor gradually increases from the initial value until the final target lateral yaw angular velocity is equal to the actual lateral yaw angular velocity. The lateral yaw amplification factor at this time is recorded as the minimum amplification factor. S32: Continue to increase the lateral alignment magnification factor until the slip ratio of each wheel reaches the preset slip limit, and record the lateral alignment magnification factor at this time as the maximum magnification factor; S33: Determine the horizontal magnification factor based on the minimum magnification factor and the maximum magnification factor.

5. The vehicle control method for reducing turning radius according to claim 4, characterized in that, Step S33 includes: According to the formula Calculate the horizontal placement coefficient. ; in, ; This is the minimum magnification factor. This refers to the maximum magnification factor; The preset weighting coefficient has a value range of [0,1].

6. The vehicle control method for reducing turning radius according to claim 4, characterized in that, The method further includes: S50: During the execution of step S40, if the actual yaw rate exceeds the initial target yaw rate amplified based on the maximum amplification factor within a consecutive preset number of monitoring cycles, or if the rate of change of the actual yaw rate reaches a preset proportion of the initial target yaw rate amplified based on the maximum amplification factor, then exit and stop executing step S40.

7. The vehicle control method for reducing turning radius according to any one of claims 1 to 6, characterized in that, Step S40 includes: S41: Construct the torque balance equation and longitudinal force balance equation that include the braking force of the inner wheel and the driving force of the outer wheel; S42: With the slip ratio of the inner wheel not exceeding a preset slip ratio threshold as a constraint, solve the torque balance equation and the longitudinal force balance equation to obtain the target braking force of the inner wheel and the target driving force of the outer wheel. S43: Control the inner wheel and the outer wheel based on the target braking force and the target driving force.

8. The vehicle control method for reducing turning radius according to claim 7, characterized in that, Step S42 includes: S421: For the inner front wheel and the inner rear wheel, closed-loop control is performed with the corresponding preset maximum allowable braking slip ratio as the target to obtain the target braking force of the inner front wheel and the target braking force of the inner rear wheel. S422: For the outer drive wheel, when calculating the target driving force, the drive slip ratio of the outer drive wheel is limited to not exceeding a preset drive slip ratio threshold.

9. A vehicle turning radius control device, characterized in that, include: The data acquisition module is used to acquire the vehicle's actual yaw rate and vehicle state parameters; The target yaw determination module is used to determine the initial target yaw rate based on the vehicle state parameters, and to correct the initial target yaw rate based on the negative yaw deviation between the actual yaw rate and the initial target yaw rate. The lateral yaw rate module is used to determine the lateral yaw rate coefficient based on the wheel slip ratio boundary, and to amplify the initial target yaw rate based on the lateral yaw rate coefficient to obtain the final target yaw rate. The torque distribution module is used to determine the target yaw torque based on the final target yaw rate and the actual yaw rate.

10. A vehicle, characterized in that, The vehicle includes the vehicle turning radius control device as described in claim 9; or, the vehicle includes a processor and a memory, the memory storing a computer program, the processor executing the computer program to implement the vehicle control method for reducing the turning radius as described in any one of claims 1 to 8.

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