Reference vehicle speed determination method and device, electronic equipment, storage medium and product

Abstract

This application provides a method, apparatus, electronic device, storage medium, and product for determining a reference vehicle speed. The method includes: determining a drive assistance strategy and a target drive torque when a vehicle is in a wheel speed distortion state; wherein the drive assistance strategy is used to determine the target wheel to be assisted; sending the target drive torque to the wheel-side drive motor controller of the target wheel, so that the wheel-side drive motor controller uses the target drive torque to provide drive assistance to the target wheel, causing the target wheel to enter an approximately pure rolling state with a slip ratio close to 0; acquiring the four wheel speeds of the vehicle after drive assistance is applied, and determining a target reference vehicle speed based on the four wheel speeds. By applying drive assistance to the target wheel when the vehicle is in a wheel speed distortion state, causing the wheel to enter an approximately pure rolling state, it is equivalent to artificially restoring a reliable wheel speed. Then, the target reference vehicle speed is calculated based on the reliable wheel speed, improving the accuracy and robustness of the target reference vehicle speed.

Description

Technical Field

[0001] This application relates to the field of vehicle safety control technology, and in particular to a method, device, electronic device, storage medium and product for determining reference vehicle speed. Background Technology

[0002] In passenger vehicle braking systems, anti-lock braking system (ABS) is the core function to ensure vehicle braking safety. The accurate calculation of reference vehicle speed is the prerequisite and foundation for the effective implementation of ABS, and directly determines the accuracy, stability and braking safety of anti-lock braking system.

[0003] In the current passenger vehicle braking field, electromechanical braking is widely considered the mainstream solution for the next generation of braking systems. Due to the limitations of motor characteristics, the anti-lock braking control of electromechanical braking generally adopts continuous slip control. Its reference vehicle speed is calculated based on vehicle dynamics and kinematic principles, using methods such as Kalman filtering fusion. However, the actual braking torque used in the vehicle dynamics part is limited by various factors such as clamping force control accuracy, friction disc temperature, and friction pad wear. Its accuracy is difficult to maintain consistently across all operating conditions, resulting in the inability of the reference vehicle speed to meet actual braking requirements in terms of accuracy and robustness. Summary of the Invention

[0004] This application provides a method, apparatus, electronic device, storage medium, and product for determining a reference vehicle speed, in order to improve the accuracy and robustness of the calculated reference vehicle speed.

[0005] In a first aspect, embodiments of this application provide a method for determining a reference vehicle speed, the method comprising:

[0006] When the vehicle is in a state of wheel speed distortion, a drive assistance strategy and a target drive torque are determined; wherein, the drive assistance strategy is used to determine the target wheel to be driven and assisted.

[0007] The target driving torque is sent to the wheel-side drive motor controller of the target wheel, so that the wheel-side drive motor controller uses the target driving torque to drive the target wheel, so that the target wheel enters an approximately pure rolling state with a slip ratio close to 0.

[0008] The vehicle acquires the speeds of its four wheels after drive assistance is applied, and determines the target reference speed based on these four wheel speeds.

[0009] In an optional implementation, the method further includes:

[0010] When all four wheels of the vehicle are under anti-lock braking control, if the vehicle meets any one of the following three conditions, the vehicle is determined to be in a wheel speed distortion state, wherein the three conditions include: steering condition, duration condition, and slip ratio condition.

[0011] Among them, the steering condition is that the longitudinal acceleration is opposite to the direction of vehicle movement and the duration of lateral acceleration - yaw rate * longitudinal speed > 0 is greater than the first preset duration;

[0012] The duration condition is that the duration during which all four wheels are under anti-lock braking control exceeds the second preset duration;

[0013] The slip ratio condition is that the duration for which the minimum longitudinal slip ratio of the four wheels exceeds the first preset threshold exceeds the third preset duration.

[0014] In one optional implementation, the drive assistance strategy includes a single-sided drive strategy and a diagonal drive strategy. The single-sided drive strategy refers to a control strategy that applies drive assistance to the front and rear wheels on the same side of the turn, based on the vehicle's oversteer direction. The diagonal drive strategy refers to a control strategy that alternates between applying drive assistance to the left front and right rear wheels as one group and the right front and left rear wheels as another group. Determining the drive assistance strategy includes:

[0015] If the vehicle meets the duration condition or the slip ratio condition, then the drive assistance strategy is determined to be a diagonal drive strategy.

[0016] If the vehicle meets the steering conditions, then the drive assistance strategy is determined to be a one-sided drive strategy.

[0017] In one alternative implementation, after all four wheels of the vehicle have engaged anti-lock braking control, the method further includes:

[0018] Obtain the current vehicle status parameters, and determine whether the vehicle is in a functional abnormal state based on the current vehicle status parameters;

[0019] Accordingly, if the vehicle meets any one of the following three conditions, the vehicle is determined to be in a state of wheel speed distortion, including:

[0020] If the vehicle is not in a malfunctioning state and the vehicle meets any one of the following three conditions, then the vehicle is determined to be in a wheel speed distortion state.

[0021] In one optional implementation, sending the target drive torque to the wheel-side drive motor controller of the target wheel includes:

[0022] Determine whether the target actuator corresponding to the target wheel is in a fault state;

[0023] If the target actuator corresponding to the target wheel is not in a fault state, the target drive torque is sent to the wheel-side drive motor controller of the target wheel.

[0024] In one alternative implementation, determining the target drive torque includes:

[0025] Obtain the current road surface adhesion coefficient;

[0026] A target mapping table corresponding to the drive assistance strategy is determined, and at least one drive assistance strategy corresponds one-to-one with at least one mapping table; wherein, the mapping table is used to indicate the correspondence between multiple road surface adhesion coefficients and multiple drive torques;

[0027] The target driving torque is determined based on the current road surface adhesion coefficient and target mapping relationship table.

[0028] In an alternative implementation, after determining the drive assistance strategy and the target drive torque, the method further includes:

[0029] The wheel speed synchronization execution request is sent to the electromechanical brake controller so that when the electromechanical brake controller receives the wheel speed synchronization execution request, it freezes the feedforward torque term and clears the feedback torque to zero when performing slip ratio closed-loop control and calculating braking torque for the target wheel. The wheel speed synchronization execution request includes the identification information corresponding to the target wheel.

[0030] In one optional implementation, determining the target reference vehicle speed based on the four wheel speeds includes:

[0031] The maximum wheel speed of the target wheel or the maximum speed among the four wheels is used as the maximum limit for the target reference vehicle speed;

[0032] The target reference vehicle speed is determined based on the speeds of the four wheels and the maximum value limit.

[0033] Secondly, embodiments of this application provide a reference vehicle speed determination device, the device comprising:

[0034] The first determining module is used to determine a drive assistance strategy and a target drive torque when the vehicle is in a wheel speed distortion state; wherein, the drive assistance strategy is used to determine the target wheel to be driven and assisted.

[0035] The sending module is used to send the target driving torque to the wheel-side drive motor controller of the target wheel, so that the wheel-side drive motor controller can use the target driving torque to drive the target wheel, so that the target wheel enters an approximately pure rolling state with a slip ratio close to 0.

[0036] The second determining module is used to acquire the speed of the four wheels of the vehicle after drive assistance is applied, and to determine the target reference speed based on the speed of the four wheels.

[0037] Thirdly, embodiments of this application provide an electronic device, including: a memory and a processor;

[0038] The memory stores computer-executed instructions;

[0039] The processor executes computer execution instructions stored in the memory, causing the processor to perform various possible implementations as described above.

[0040] Fourthly, embodiments of this application provide a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement various possible implementations as described in any of the above aspects.

[0041] Fifthly, embodiments of this application provide a computer program product, including a computer program that, when executed by a processor, implements various possible implementations as described in any of the above aspects.

[0042] The reference vehicle speed determination method, apparatus, electronic device, storage medium, and product provided in this application include: determining a drive assistance strategy and a target drive torque when the vehicle is in a wheel speed distortion state; wherein the drive assistance strategy is used to determine the target wheel to be assisted; sending the target drive torque to the wheel-side drive motor controller of the target wheel, so that the wheel-side drive motor controller uses the target drive torque to assist the target wheel, so that the target wheel enters an approximately pure rolling state with a slip ratio close to 0; acquiring the four wheel speeds of the vehicle after drive assistance, and determining a target reference vehicle speed based on the four wheel speeds. By applying drive assistance to the target wheel when the vehicle is in a wheel speed distortion state, so that the wheel enters an approximately pure rolling state with a slip ratio close to 0, it is equivalent to artificially repairing a reliable wheel speed, and then calculating the target reference vehicle speed based on the reliable wheel speed, thereby improving the accuracy and robustness of the target reference vehicle speed. Attached Figure Description

[0043] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0044] Figure 1 An application scenario diagram provided for an embodiment of this application;

[0045] Figure 2 A flowchart illustrating a method for determining a reference vehicle speed provided in an embodiment of this application;

[0046] Figure 3 A flowchart illustrating another method for determining reference vehicle speed provided in an embodiment of this application;

[0047] Figure 4 A flowchart illustrating yet another method for determining reference vehicle speed provided in an embodiment of this application;

[0048] Figure 5 This is a schematic diagram of the wheel speed synchronization waveform corresponding to a diagonal drive strategy provided in an embodiment of this application;

[0049] Figure 6 This is a schematic diagram of the wheel speed synchronization waveform corresponding to a unilateral drive strategy provided in an embodiment of this application;

[0050] Figure 7 A schematic diagram of a system architecture provided for an embodiment of this application;

[0051] Figure 8 A schematic diagram of a reference vehicle speed determination device provided in an embodiment of this application;

[0052] Figure 9 A schematic diagram of the structure of the electronic device provided in this application.

[0053] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0054] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0055] In passenger vehicle braking systems, ABS is the core function ensuring vehicle braking safety. Accurate calculation of the reference vehicle speed is the prerequisite and foundation for the effective implementation of ABS, directly determining the precision, stability, and braking safety of anti-lock braking control. As the core input parameter for ABS slip ratio calculation, the robustness and accuracy of the calculation directly affect the slip ratio control effect. If the reference vehicle speed estimation deviates too much, the ABS system will misjudge the wheel slip state, failing to control the wheel slip ratio within the optimal braking range, thus leading to safety hazards such as wheel lock-up, increased braking distance, and loss of vehicle control. Therefore, how to achieve accurate and stable calculation of the reference vehicle speed is a key technical problem that urgently needs to be solved in the field of passenger vehicle braking.

[0056] In the current passenger vehicle braking field, electromechanical braking is widely considered the mainstream solution for the next generation of braking systems. Electromechanical braking controls clamping force through motors, reducers, and transmission mechanisms. Its decompression action requires the motor to first stop rotating forward and then reverse, placing higher demands on the response performance of the electromechanical braking assembly. Therefore, for electromechanical braking, ABS generally uses a continuous slip control algorithm, and its reference vehicle speed is calculated based on vehicle dynamics and kinematic principles using methods such as Kalman filtering fusion. However, the actual braking torque used in the vehicle dynamics section is limited by various factors such as clamping force control precision, friction disc temperature, and friction pad wear, resulting in a very complex influencing mechanism. This makes it difficult to maintain the high precision requirement of vehicle dynamics for actual braking torque consistently across all operating conditions, leading to the inability to meet the accuracy and robustness of the reference vehicle speed in actual braking needs.

[0057] In view of this, this application provides a method for determining a reference vehicle speed. The vehicle motion control system can determine a drive assistance strategy and a target drive torque when the vehicle is in a wheel speed distortion state. The drive assistance strategy is used to determine the target wheel to be assisted. The target drive torque is sent to the wheel-side drive motor controller of the target wheel, so that the wheel-side drive motor controller uses the target drive torque to assist the target wheel, causing the target wheel to enter an approximately pure rolling state with a slip ratio close to 0. The speeds of the four wheels after the drive assistance is applied are obtained, and the target reference vehicle speed is determined based on these speeds. By applying drive assistance to the target wheel when the vehicle is in a wheel speed distortion state, causing the wheel to enter an approximately pure rolling state with a slip ratio close to 0, it is equivalent to artificially restoring a reliable wheel speed. The target reference vehicle speed is then calculated based on this reliable wheel speed, improving the accuracy and robustness of the target reference vehicle speed.

[0058] Figure 1 An application scenario diagram provided for an embodiment of this application, such as Figure 1As shown, the vehicle motion control system first determines whether the vehicle is in a wheel speed distortion state. If the vehicle is not in a wheel speed distortion state, the target reference vehicle speed is calculated using conventional methods based on vehicle dynamics and kinematics. If the vehicle is in a wheel speed distortion state, the drive assistance strategy and target drive torque are determined. Based on the drive assistance strategy, the target wheel to be assisted is determined, and the target drive torque is sent to the wheel-side drive motor controller of the target wheel. After receiving the target drive torque, the wheel-side drive motor controller uses the target drive torque to provide drive assistance to the target wheel, causing the target wheel to enter an approximately pure rolling state with a slip ratio close to 0. Then, the vehicle motion control system acquires the four-wheel speeds after drive assistance from the EMB (Electro-Mechanical Brake) controller, and determines the target reference vehicle speed based on the acquired four-wheel speeds.

[0059] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0060] Figure 2 This is a flowchart illustrating a reference vehicle speed determination method provided in an embodiment of this application. The executing entity in this embodiment can be any device with data processing capabilities. This application uses a vehicle motion control system (VMC) as an example for specific illustration. Figure 2 As shown in the embodiment of this application, a method for determining a reference vehicle speed is provided, the method comprising:

[0061] Step 201: When the vehicle is in a state of wheel speed distortion, determine the drive assistance strategy and the target drive torque; wherein, the drive assistance strategy is used to determine the target wheel to be driven and assisted.

[0062] Among them, the vehicle motion control system refers to the core controller of the vehicle chassis domain, which is responsible for coordinating the longitudinal and lateral dynamic control of the vehicle and unifying and coordinating functions such as the electromechanical braking system, wheel-side drive system, and anti-lock braking (ABS).

[0063] The drive assist strategy is designed to correct wheel speed distortion and obtain reliable wheel speeds. It is used to determine which wheel(s) or wheels need to be given drive assist and to define the target wheel(s).

[0064] The target driving torque is the positive driving torque applied to the target wheel to make the target wheel slip ratio close to 0, resulting in an approximately pure rolling state, in order to obtain a reliable wheel speed signal.

[0065] A vehicle is in a state of wheel speed distortion when the wheel speeds of the four wheels can no longer reliably reflect the vehicle's true driving speed. This state will cause the reference speed calculated based on wheel speed to become invalid.

[0066] Specifically, when the vehicle motion control system is in a state of wheel speed distortion, it determines the drive assistance strategy and the target drive torque.

[0067] This application does not limit the specific implementation of whether the vehicle is in a state of wheel speed distortion. In one optional implementation, whether the vehicle is in a state of wheel speed distortion can be determined by the following method:

[0068] When all four wheels of a vehicle are under anti-lock braking control, if the vehicle meets any one of the following three conditions, it is determined that the vehicle is in a state of wheel speed distortion. The three conditions include: steering condition, duration condition, and slip ratio condition.

[0069] Among them, the steering condition is that the longitudinal acceleration is opposite to the direction of vehicle movement and the duration of lateral acceleration - yaw rate * longitudinal speed > 0 is greater than the first preset duration;

[0070] The duration condition is that the duration during which all four wheels are under anti-lock braking control exceeds the second preset duration;

[0071] The slip ratio condition is that the duration for which the minimum longitudinal slip ratio of the four wheels exceeds the first preset threshold exceeds the third preset duration.

[0072] Anti-lock braking system (ABS) refers to a closed-loop control process in which the EMB controller monitors the wheel speeds of all four wheels in real time during vehicle braking, and adjusts the braking clamping force by controlling the EMB actuator to prevent wheel lock-up and slippage, thereby keeping the wheel slip ratio within the optimal braking range.

[0073] When the vehicle brakes, the EMB controller main controller monitors the status of the four wheels in real time. When all four wheels of the vehicle are in anti-lock braking control, it sends a first signal to the vehicle motion control system. The first signal indicates that all four wheels of the vehicle are in anti-lock braking control. After receiving the first signal, the vehicle motion control system determines whether the vehicle meets any one of the following three conditions. If any one of the three conditions is met, the vehicle is determined to be in a wheel speed distortion state. The three conditions are: steering condition, duration condition, and slip ratio condition.

[0074] When determining whether a vehicle meets the steering conditions, the vehicle motion control system first acquires the vehicle's longitudinal acceleration, lateral acceleration, yaw rate, and longitudinal speed. Then, it starts timing when the longitudinal acceleration is opposite to the vehicle's direction of motion and when lateral acceleration - yaw rate * longitudinal speed > 0. If the duration of this timing exceeds a first preset duration, the vehicle is deemed to meet the steering conditions; if the duration is less than the first preset duration, the vehicle is deemed not to meet the steering conditions. Here, longitudinal acceleration is the vehicle's acceleration in the direction of travel, reflecting how quickly the vehicle's speed changes in that direction. Lateral acceleration is the vehicle's acceleration in the lateral direction, reflecting the intensity of lateral movement during turning, tilting, and lane changes. Yaw rate is the angular velocity of the vehicle around its vertical axis, also called the vehicle body turning angular velocity, reflecting the speed of turning and steering stability. Longitudinal speed is the instantaneous speed of the vehicle along the direction of travel, which can be calculated using existing technology to obtain a reference speed. Lateral acceleration reflects the force of a vehicle's lateral sway, while yaw rate multiplied by longitudinal speed reflects the theoretically expected lateral force of the vehicle. Lateral acceleration - yaw rate multiplied by longitudinal speed > 0 indicates that the vehicle is in an oversteer state.

[0075] The specific method for calculating reference vehicle speed using existing technology is as follows:

[0076] The vehicle motion control system calculates the vehicle's kinematic speed based on basic signals such as wheel speed and steering wheel angle received from the chassis CAN bus, according to the following formula.

[0077]

[0078] in, The kinematic speed of the vehicle is calculated for the four wheel speeds. , , , For four rounds of confidence, The sum of the confidence levels for the four rounds. , , , The wheel speeds of the four wheels are projected onto the center of gravity of the entire vehicle.

[0079] Then, based on the basic signals such as braking torque, drive torque, and IMU received from the chassis CAN bus, the dynamic acceleration of the whole vehicle is calculated according to the following formula.

[0080]

[0081] in, The acceleration of the entire vehicle without any incline; The longitudinal acceleration measured by the IMU; This is the sum of the longitudinal forces of the four wheels, expressed in N. air density; This refers to the air drag coefficient; The windward area is expressed in m². Longitudinal reference speed, unit: mps; The total vehicle weight is expressed in kg. It is the acceleration due to gravity; This is the derivative of the reference speed of the previous vehicle.

[0082] Finally, the kinematic vehicle speed and dynamic acceleration are fused using the Kalman filter formula shown below to obtain the conventional reference vehicle speed.

[0083]

[0084]

[0085]

[0086]

[0087]

[0088] in, Kalman gain; and for time, The posterior estimate of the covariance at time t. The covariance prior prediction; and They represent Time and The posterior state estimate at time t, where, ; Let K be the prior state prediction. Let H be the state prior prediction at time K-1; H be the transformation matrix; A be the state transition matrix; and Q be the process excitation noise covariance. This is the state transition matrix; To initialize the state matrix; R is the measurement noise covariance, i.e. , It is the variance of the dynamics. It is the variance of the kinematics.

[0089] When the vehicle motion control system receives the first signal, it starts timing. If the duration of continuously receiving the first signal exceeds a second preset duration, the vehicle is determined to meet the duration condition. If the duration of continuously receiving the first signal is less than the second preset duration, the vehicle is determined not to meet the duration condition. While all four wheels of the vehicle are under anti-lock braking control, the EMB controller can send the first signal to the vehicle motion control system every fourth preset duration. Therefore, if the vehicle motion control system receives the first signal every fourth preset duration, and the duration of receiving the first signal every fourth preset duration exceeds the second preset duration, the vehicle is determined to meet the duration condition, where the second preset duration is longer than the fourth preset duration.

[0090] The vehicle motion control system calculates the longitudinal slip ratio for each of the four wheels. Timing begins when the minimum longitudinal slip ratio among the four wheels exceeds a first preset threshold. If the duration for which the minimum longitudinal slip ratio exceeds the first preset threshold exceeds a third preset duration, the vehicle meets the slip ratio condition. If the duration for which the minimum longitudinal slip ratio exceeds the first preset threshold does not exceed the third preset duration, the vehicle does not meet the slip ratio condition. Wherein, the longitudinal slip ratio s = (v... 参考 -v 车轮 ) / v 参考 v 参考 v is the reference vehicle speed calculated using existing technology. 车轮 This refers to the wheel speed.

[0091] In this way, by comprehensively judging the wheel speed distortion from three dimensions—steering condition, duration condition, and slip ratio condition—it covers not only the dynamic abnormal wheel speed distortion under combined braking and steering conditions, but also the cumulative wheel speed distortion caused by prolonged ABS control, and the reference speed failure distortion caused by high four-wheel slip. This avoids omissions or misjudgments caused by judging based on a single condition. Furthermore, each condition has a corresponding duration threshold to prevent misjudgments caused by interference factors such as instantaneous signal fluctuations, sensor noise, and brief changes in operating conditions. This ensures that the wheel speed distortion state judgment results are stable and reliable, providing a credible triggering basis for the subsequent activation of drive assistance strategies.

[0092] In one optional implementation, the drive assist strategy includes a single-sided drive strategy and a diagonal drive strategy. The single-sided drive strategy refers to a control strategy that applies drive assist to the front and rear wheels on the same side of the turn, based on the vehicle's oversteer direction. The diagonal drive strategy refers to a control strategy that alternates between applying drive assist to the left front and right rear wheels as one group and the right front and left rear wheels as another group. Determining the drive assist strategy includes:

[0093] If the vehicle meets the duration or slip ratio conditions, the drive assistance strategy is determined to be a diagonal drive strategy.

[0094] If the vehicle meets the steering requirements, the drive assist strategy is determined to be a one-sided drive strategy.

[0095] The direction of oversteer can be determined based on the steering wheel angle. Oversteer occurs when the longitudinal acceleration is opposite to the vehicle's direction of motion and the lateral acceleration - yaw rate * longitudinal speed > 0. Under the condition of oversteer, if the steering wheel is turned to the left during this process, the oversteer direction is to the left, and the corresponding inside of the turn is the left side. If the steering wheel is turned to the right during this process, the oversteer direction is to the right, and the corresponding inside of the turn is the right side.

[0096] Therefore, when the vehicle meets the steering conditions, that is, when the vehicle is in an oversteering state, the vehicle motion control system determines the drive assistance strategy to be a one-sided drive strategy. If it is further determined that the oversteering direction is to the left, drive assistance is applied to the left front and rear wheels, that is, the left front and left rear wheels are the target wheels to be driven and assisted; if it is further determined that the oversteering direction is to the right, drive assistance is applied to the right front and right rear wheels, that is, the right front and right rear wheels are the target wheels to be driven and assisted.

[0097] If the vehicle meets the duration or slip ratio conditions, the vehicle motion control system determines the drive assistance strategy as the diagonal drive strategy. The diagonal drive strategy refers to the control strategy that alternates between applying drive assistance between the two groups of diagonally opposite wheels, with the left front wheel and the right rear wheel forming one group and the right front wheel and the left rear wheel forming another group.

[0098] In one example, during the time interval 0 to t, the left front wheel and the right rear wheel are used as target wheels for auxiliary driving. Then, during the time interval t to 2t, the right front wheel and the left rear wheel are used as target wheels for auxiliary driving. Then, during the time interval 2t to 3t, the left front wheel and the right rear wheel are used as target wheels for auxiliary driving, and so on.

[0099] In another example, during the time interval 0 to t, the right front wheel and the left rear wheel are used as target wheels for auxiliary driving. Then, during the time interval t to 2t, the left front wheel and the right rear wheel are used as target wheels for auxiliary driving. Then, during the time interval 2t to 3t, the right front wheel and the left rear wheel are used as target wheels for auxiliary driving, and so on.

[0100] In the example above, after assisted driving of the left front wheel and right rear wheel, assisted driving of the right front wheel and left rear wheel is immediately applied, followed by assisted driving of the left front wheel and right rear wheel. After a certain interval, assisted driving of the right front wheel and left rear wheel is applied again. For example, during the time period 0 to t, the left front wheel and right rear wheel are used as the target wheels for assisted driving. During the time period 2t to 3t, the right front wheel and left rear wheel are used as the target wheels for assisted driving. Then, during the time period 4t to 5t, the left front wheel and right rear wheel are used as the target wheels for assisted driving, and so on.

[0101] In this way, under oversteer conditions, the single-wheel drive strategy can quickly pull the inner wheel back to a pure rolling state, restoring the vehicle's steering control and ensuring that the driver can still control the vehicle's trajectory through the steering wheel, greatly improving active safety in emergency situations. When the vehicle meets the time or slip ratio conditions, the diagonal drive strategy has better symmetry in the vehicle's longitudinal and lateral dynamics. Under extreme conditions of high four-wheel slip and unstable vehicle posture, diagonal drive assistance will not exacerbate vehicle yaw or roll, helping to maintain vehicle stability and avoid skidding and loss of control.

[0102] In an optional implementation, after all four wheels of the vehicle have entered anti-lock braking control, the reference vehicle speed determination method provided in this application embodiment further includes:

[0103] Obtain the current vehicle status parameters, and determine whether the vehicle is in a malfunctioning state based on the current vehicle status parameters;

[0104] Accordingly, if a vehicle meets any one of the following three conditions, it is determined that the vehicle is in a state of wheel speed distortion, including:

[0105] If the vehicle is not in a malfunctioning state and meets any one of the following three conditions, then the vehicle is determined to be in a state of wheel speed distortion.

[0106] Vehicle status parameters refer to the set of parameters collected or calculated in real time by the vehicle motion control system to characterize the current operating conditions of the vehicle and the working status of each system. For example, vehicle status parameters can include the working status of the EMB system, the status of the drive motor, the working status of the traction control system (TCS), system fault codes, sensor status, etc.

[0107] A functional abnormality refers to a situation where the vehicle is experiencing a system malfunction, other dynamic control systems are intervening, or the current control mode is unsuitable for activating drive assistance. In one example, a functional abnormality could be a fault in critical components such as the EMB controller, wheel-side drive motor controller, or IMU (Inertial Measurement Unit). In another example, it could be that the traction control system, or dynamic control systems such as dTCS (Dynamic Traction Control System) or electronic stability control system are activated. In yet another example, the vehicle may have other system alarms or fault limitations that affect the normal execution of braking and drive.

[0108] Specifically, the vehicle motion control system acquires the current vehicle status parameters and determines whether the vehicle is in a malfunctioning state based on these parameters. If the vehicle is not in a malfunctioning state and meets any one of the following three conditions, then the vehicle is determined to be in a wheel speed distortion state. If the vehicle is in a malfunctioning state, the current process ends directly without further judgment on wheel speed distortion.

[0109] In this way, when dynamic control systems such as ESP (Electronic Stability Program), TCS, and dTCS intervene in the vehicle, it is determined to be a functional abnormality and the triggering of wheel speed distortion repair logic is prohibited. This prevents the drive assistance of this solution from acting simultaneously with other stability control functions, avoiding control command conflicts and ensuring vehicle driving safety. Furthermore, when components such as sensors, EMB actuators, and drive motors malfunction, the wheel speed signal itself becomes unreliable. In this case, not triggering wheel speed distortion judgment can avoid executing invalid or even erroneous drive assistance operations under fault conditions, improving the robustness of the entire braking control system.

[0110] In one alternative implementation, determining the target drive torque includes:

[0111] Obtain the current road surface adhesion coefficient;

[0112] A target mapping table corresponding to the drive assistance strategy is determined, and at least one drive assistance strategy corresponds one-to-one with at least one mapping table; wherein, the mapping table is used to indicate the correspondence between multiple road surface adhesion coefficients and multiple drive torques;

[0113] The target driving torque is determined based on the current road surface adhesion coefficient and target mapping relationship table.

[0114] The road surface adhesion coefficient refers to the ratio of the actual tangential force between the tire and the road surface during braking or driving to the corresponding vertical load on the wheel. It is used to characterize the degree to which the maximum adhesion potential provided by the current road surface is utilized and reflects the quality of road surface adhesion conditions.

[0115] There can be at least one drive assistance strategy, and each drive assistance strategy corresponds to a different mapping table. Based on the identification information corresponding to the drive assistance strategy, the name of the target mapping table corresponding to the drive assistance strategy can be determined through the strategy mapping table. Then, the target mapping table is determined based on the name of the target mapping table. The strategy mapping table is used to indicate the correspondence between the identification information of multiple drive assistance strategies and the names of multiple mapping tables. The mapping table is also used to indicate the correspondence between multiple road surface adhesion coefficients and multiple drive torques.

[0116] Then, based on the current road surface adhesion coefficient, the driving torque corresponding to the current road surface adhesion coefficient can be determined by querying the target mapping relationship table, which is the target driving torque.

[0117] Furthermore, the auxiliary drive to the target wheel will continue for a period of time. During this period, the target drive torque will be continuously calculated. The multiple target drive torques obtained will be normalized to obtain the loading curve of the target drive torque.

[0118] In this way, by determining the target driving torque based on the road surface adhesion coefficient, the driving intensity can be dynamically adjusted according to the actual road surface adhesion conditions. This avoids wheel slippage and increased wheel speed distortion caused by excessive driving torque, and also avoids the inability to restore the target wheel to a near-pure rolling state due to insufficient torque, ensuring stable and reliable driving assistance. Furthermore, independent mapping tables are set up for different driving assistance strategies, which can be specifically matched to the dynamic characteristics of steering conditions and long-term high-slip conditions, making the driving torque output more consistent with actual working conditions and improving the accuracy of reference vehicle speed correction.

[0119] In an optional implementation, after determining the drive assistance strategy and the target drive torque, the reference vehicle speed determination method provided in this application embodiment further includes:

[0120] The wheel speed synchronization execution request is sent to the electromechanical brake controller so that when the electromechanical brake controller receives the wheel speed synchronization execution request, it freezes the feedforward torque term and clears the feedback torque to zero when performing slip ratio closed-loop control and calculating braking torque for the target wheel. The wheel speed synchronization execution request includes the identification information corresponding to the target wheel.

[0121] In the electromechanical brake controller, when performing closed-loop control of the slip ratio of the target wheel and calculating the braking torque, the braking torque is equal to the sum of the feedforward torque and the feedback torque. The braking torque is the total braking control quantity output by the electromechanical brake controller and applied to the wheel, used to achieve wheel braking and anti-lock braking control.

[0122] Feedforward torque is the braking torque component pre-calculated by the electromechanical brake controller based on prior operating condition information such as vehicle reference speed, road surface adhesion coefficient, and target slip ratio, through a preset model or lookup table method. It is used to quickly respond to braking demand and improve the system response speed.

[0123] Feedback torque is the braking torque component calculated by the electromechanical brake controller based on the deviation between the actual slip ratio and the target slip ratio through a closed-loop control algorithm. It is used to correct the braking torque in real time, eliminate slip ratio errors, and ensure that the wheel remains stable within the target slip ratio range.

[0124] When performing the aforementioned diagonal drive assist or single-sided drive assist, the actual wheel speed will be pulled back to a pure rolling state for a short time. At this time, for continuous slip ABS control, the slip ratio difference will be artificially increased, and the braking torque based on continuous slip control will increase, as shown in the following formula.

[0125]

[0126] in, For feedback torque, For proportional gain, For slip ratio error, is the integration time constant.

[0127] To address the braking resistance effect during drive assistance, the ABS continuous slip control needs to be temporarily switched to cooperative control. The vehicle motion control system sends a wheel speed synchronization execution request to the electromechanical brake controller. Upon receiving the wheel speed synchronization execution request, the electromechanical brake controller freezes the feedforward torque term and clears the feedback torque to zero when performing slip ratio closed-loop control on the target wheel and calculating the braking torque. This ensures that drive assistance can easily pull the wheel speed back to pure rolling state with a very small amount of drive torque, thereby improving drive efficiency.

[0128] Step 202: Send the target driving torque to the wheel-side drive motor controller of the target wheel, so that the wheel-side drive motor controller can use the target driving torque to drive the target wheel, so that the target wheel enters an approximately pure rolling state with a slip ratio close to 0.

[0129] Specifically, the vehicle motion control system sends the target drive torque to the wheel-side drive motor controller of the target wheel. After receiving the target drive torque, the wheel-side drive motor controller of the target wheel uses the target drive torque to drive the target wheel, so that the target wheel enters an approximately pure rolling state with a slip ratio close to 0.

[0130] In one alternative implementation, the method of sending the target drive torque to the wheel-side drive motor controller of the target wheel includes:

[0131] Determine whether the target actuator corresponding to the target wheel is in a faulty state;

[0132] If the target actuator corresponding to the target wheel is not in a fault state, the target drive torque is sent to the wheel-side drive motor controller of the target wheel.

[0133] Specifically, the vehicle motion control system can determine whether the target actuator corresponding to the target wheel is in a faulty state through the following methods:

[0134] The vehicle motion control system receives real-time status signals from the wheel-side drive motor controller corresponding to the target wheel, including motor status, controller status, communication status, temperature status, and fault code information. It also receives actuator status signals from the wheel-side drive motor controller. If the wheel-side drive motor controller or motor experiences over-temperature, over-current, overload, communication interruption, or hardware fault alarms, or if the target wheel actuator displays a fault indication indicating malfunction, the target actuator is determined to be in a faulty state. The wheel-side drive motor controller is used to send the target drive torque to the target actuator corresponding to the target wheel for drive assistance.

[0135] If the target actuator corresponding to the target wheel is not in a faulty state, the target drive torque is sent to the wheel-side drive motor controller of the target wheel. The wheel-side drive motor controller then sends the target drive torque to the target actuator corresponding to the target wheel, and the target actuator provides drive assistance based on the target drive torque. If the target actuator corresponding to the target wheel is in a faulty state, the process ends, and the sending of the target drive torque to the wheel-side drive motor controller of the target wheel stops.

[0136] Alternatively, if the target actuator corresponding to the target wheel has dTCS activated, the handling method is the same as when the target actuator is faulty. If the target actuator is not faulty and dTCS is not activated, the target drive torque is sent to the wheel-side drive motor controller of the target wheel.

[0137] In this way, by determining whether the target actuator is faulty before sending the target drive torque, invalid control commands can be issued when the target actuator is faulty, malfunctioning, or has communication abnormalities. This prevents safety risks such as loss of drive assistance and abnormal fluctuations in wheel speed caused by actuator abnormalities, and improves the safety of system operation.

[0138] Step 203: Obtain the speed of the four wheels of the vehicle after drive assistance is applied, and determine the target reference speed based on the speed of the four wheels.

[0139] Specifically, after acquiring the speeds of the four wheels of the vehicle after drive assistance is applied, the vehicle motion control system can determine the target reference speed based on the speeds of the four wheels after drive assistance is applied.

[0140] In one alternative implementation, determining the target reference vehicle speed based on the four wheel speeds includes:

[0141] The maximum wheel speed of the target wheel or the maximum speed among the four wheels is used as the maximum limit for the target reference vehicle speed;

[0142] Determine the target reference speed based on the speed of the four wheels and the maximum limit.

[0143] Specifically, the vehicle motion control system can use the maximum wheel speed of the target wheel or the maximum speed among the four wheels as the maximum limit of the target reference vehicle speed, while actively setting the dynamic vehicle speed, i.e. the speed of the four wheels, as reliable, and not participating in the fusion of kinematic acceleration, in order to obtain the target reference vehicle speed.

[0144] In this way, under the influence of the drive assistance strategy, the target wheel is controlled into a near-pure rolling state, and its wheel speed is closest to the vehicle's actual speed. Limiting the speed to the maximum value of the target wheel speed, or taking the maximum value of all four wheel speeds, essentially utilizes the reliable wheel speed after wheel speed repair as a benchmark, ensuring the highest reliability of the reference speed. Furthermore, when road surface adhesion is complex or wheel speed signals fluctuate, this limiting mechanism can automatically filter abnormal peak signals or interference noise, making the final calculated target reference speed more stable and robust, unaffected by local instantaneous signal anomalies.

[0145] The reference vehicle speed determination method provided in this application can determine a drive assistance strategy and a target drive torque when the vehicle is in a wheel speed distortion state. The drive assistance strategy is used to determine the target wheel to be assisted. The target drive torque is sent to the wheel-side drive motor controller of the target wheel, so that the wheel-side drive motor controller uses the target drive torque to assist the target wheel, causing the target wheel to enter an approximately pure rolling state with a slip ratio close to 0. The speeds of the four wheels after the drive assistance is applied are obtained, and the target reference vehicle speed is determined based on these speeds. By applying drive assistance to the target wheel when the vehicle is in a wheel speed distortion state, causing the wheel to enter an approximately pure rolling state with a slip ratio close to 0, it is equivalent to artificially repairing a reliable wheel speed. The target reference vehicle speed is then calculated based on this reliable wheel speed, improving the accuracy and robustness of the target reference vehicle speed.

[0146] Figure 3 The flowchart illustrates another method for determining reference vehicle speed provided in this application embodiment. The vehicle motion control system first calculates and obtains a conventional initial reference vehicle speed based on the vehicle dynamics model and kinematic model, combined with the vehicle's current driving state, such as acceleration, speed, and attitude. This initial reference vehicle speed serves as the basis for subsequent wheel speed synchronization calculations, providing preliminary prior information about the vehicle speed.

[0147] When a vehicle enters a special operating condition where all four wheels are under anti-lock braking control, the VMC wheel speed synchronization recognition module collects wheel speed and vehicle attitude signals in real time, such as yaw rate and lateral acceleration, to identify the current wheel speed status of the vehicle and determine the corresponding drive assistance strategy, such as a single-sided drive strategy or a diagonal drive strategy. At the same time, it selects the available actuators to participate in the coordinated control, namely the wheel-side drive motors corresponding to the target wheel.

[0148] VMC combines the established drive assistance strategy, the status of available actuators, and the current road surface adhesion coefficient to perform comprehensive planning, ultimately determining the target drive torque. The target drive torque is then sent to the target actuator, which performs wheel speed synchronization and repair operations, bringing the target wheel into a near-pure rolling state.

[0149] The wheel speed synchronization status information is sent to the ABS control module. The ABS control module will perform operations such as freezing the feedforward torque and clearing the feedback torque to achieve coordinated control, ensuring that the wheel speed synchronization process is stable and accurate, and avoiding control conflicts or oscillations.

[0150] Finally, VMC uses the wheel speed signal restored to a realistic and reliable state, combined with vehicle dynamics and kinematic models, to update the initial conventional braking reference speed in real time. This results in an accurate and continuous target reference speed, providing reliable speed input for vehicle anti-lock braking and other active safety controls.

[0151] Figure 4 A flowchart illustrating another method for determining reference vehicle speed provided in this application embodiment is shown below. Figure 4 As shown, the Vehicle Motion Control System (VMC) first calculates the conventional braking reference speed based on the vehicle dynamics model and kinematic model, combined with the vehicle's current driving state, such as acceleration, speed, and attitude, as the basic benchmark for subsequent control.

[0152] The Vehicle Controller (VMC) determines in real time whether the vehicle meets the trigger conditions for all four wheels to enter ABS control. If not, it continues to calculate the normal reference vehicle speed and does not proceed to the next step. If the conditions are met, it further determines whether the vehicle is in a malfunctioning state. If the vehicle is in a malfunctioning state, it exits the drive assist strategy. If the vehicle is not in a malfunctioning state, the VMC determines whether to implement drive assist and the corresponding drive assist strategy based on signals such as wheel speed, yaw rate, and lateral acceleration. It also selects available actuators with execution capabilities. If the drive assist strategy is a diagonal drive strategy, the VMC executes diagonal drive torque planning. If it is determined to be a unilateral drive strategy, the VMC executes unilateral drive torque planning. Each drive assist strategy includes a fault self-check for the target actuator to ensure that healthy actuators receive commands.

[0153] After torque planning is completed, the VMC sends wheel speed synchronization status information to the ABS control module. The ABS control module then performs real-time coordinated control based on this status, adjusting the coordination between braking torque and drive torque. Simultaneously, the VMC updates the initial conventional reference vehicle speed in real time by fusing and restoring reliable wheel speed signals from the pure rolling state, generating an accurate target reference vehicle speed.

[0154] VMC determines whether the drive assist has been completed (e.g., the four-wheel slip ratio has returned to normal and the reference vehicle speed is stable). If it has not been completed, it returns to the step of determining whether the vehicle is in a functional abnormal state and continues to perform closed-loop correction. If it has been completed, it exits the drive assist and returns to the normal ABS control logic, and the method ends.

[0155] Figure 5 This application provides a schematic diagram of wheel speed synchronization waveforms corresponding to a diagonal drive strategy, as shown in the embodiment. Figure 5 As shown, this diagram illustrates the relationship between key signals and time under four-wheel ABS control conditions, using a diagonal drive strategy for drive assistance. The meanings of each curve and the working process are as follows:

[0156] The topmost curve shows the relationship between the actual braking torque of the electromechanical braking system and time. In the initial stage, the braking torque rises rapidly. After entering ABS control, the braking torque is maintained in the target range with small fluctuations, and anti-lock slip ratio closed-loop control is executed. In the later stage, the braking torque recovers and stabilizes, indicating that ABS control ends.

[0157] The second curve represents the actual driving torque corresponding to the left front wheel and right rear wheel, and the third curve represents the actual driving torque corresponding to the right front wheel and left rear wheel. The two curves are pulse-type outputs that appear alternately to correspond to the execution of the diagonal drive strategy: each time, only one set of diagonal wheels is given positive driving torque, while the driving torque of the other set of diagonal wheels is zero.

[0158] The fourth curve is the diagonal drive enable signal curve. When the first high level is high, it indicates that the left front wheel and the right rear wheel are driven. When the second high level is high, it indicates that the right front wheel and the left rear wheel are driven. When the low level is low, it indicates that no drive assistance is provided. The first high level and the second high level alternate to form a complete diagonal drive assistance cycle.

[0159] The fifth curve is the deceleration curve. It can be seen that the deceleration remains stable during the ABS control phase and does not fluctuate drastically due to the intervention of drive assistance. This indicates that the diagonal drive strategy only affects the wheel speed repair of the target wheel and does not disrupt the braking deceleration of the entire vehicle, thus ensuring the stability of braking performance.

[0160] The bottom curve represents the wheel speed versus reference vehicle speed curve. The solid line represents the ABS reference speed, showing a stable linear downward trend. The dashed lines represent the wheel speeds of the left front wheel and right rear wheel, while the dotted lines represent the wheel speeds of the right front wheel and left rear wheel, alternating with the previous set of wheels in the deviation-correction process.

[0161] Figure 6 This application provides a schematic diagram of wheel speed synchronization waveforms corresponding to a unilateral drive strategy, as shown in the embodiment. Figure 6 As shown, Figure 6The diagram illustrates the relationship between key signals and time under four-wheel ABS control conditions, using a single-sided drive strategy for drive assistance. The meanings of each curve and the working process are as follows:

[0162] The topmost curve shows the relationship between the actual braking torque of the electromechanical braking system and time. In the initial stage, the braking torque rises rapidly. After entering ABS control, the braking torque is maintained in the target range with small fluctuations, and anti-lock slip ratio closed-loop control is executed. In the later stage, the braking torque recovers and stabilizes, indicating that ABS control ends.

[0163] The second curve represents the actual driving torque corresponding to the inner front wheel, and the third curve represents the actual driving torque corresponding to the inner rear wheel. The two curves are synchronous pulse outputs, which simultaneously apply positive driving torque to the inner front and rear wheels during each control cycle, while the driving torque of the outer wheels is always zero.

[0164] The fourth curve is the single-sided drive enable signal curve. When it is high, it means that the drive assistance of the inner front and rear wheels is currently enabled; when it is low, it means that the drive assistance is paused and the inner wheels return to normal ABS control.

[0165] The fifth curve is the deceleration curve. It can be seen that the deceleration remains stable during the ABS control phase and does not fluctuate drastically due to the intervention of drive assistance. This indicates that the diagonal drive strategy only affects the wheel speed repair of the target wheel and does not disrupt the braking deceleration of the entire vehicle, thus ensuring the stability of braking performance.

[0166] The bottom curve represents the wheel speed versus reference vehicle speed curve. The solid line represents the ABS reference vehicle speed, showing a stable linear downward trend. The dashed lines represent the wheel speeds of the inner front and rear wheels, while the dotted lines represent the wheel speeds of the outer front and rear wheels.

[0167] Figure 7 A system architecture diagram provided for an embodiment of this application, such as Figure 7As shown, the system's basic input comes from the reference vehicle speed module, which is integrated within the VMC and is responsible for providing the reference vehicle speed. Calculating the reference vehicle speed requires reference to kinematic vehicle speed, dynamic acceleration, vehicle speed limit, whether drive assistance is needed, and the drive assistance strategy. When drive assistance is needed, the reference vehicle speed and drive assistance strategy are sent to the wheel speed synchronization control module. The wheel speed synchronization control module selects the target actuator based on the drive assistance strategy and calculates the target drive torque. Then, it sends the target actuator's identification information and the corresponding target drive torque to the torque coordination arbitration module. The torque coordination arbitration module determines whether the target actuator is in a fault state. If it is in a fault state, drive assistance is paused, and the reference vehicle speed is calculated using the conventional method. If it is not in a fault state, the target drive torque is sent to the wheel-side drive motor controller of the target wheel. The wheel-side drive motor controller drives the target wheel according to the target drive torque, bringing the target wheel into an approximately pure rolling state with a slip ratio close to 0. Simultaneously, the torque coordination arbitration module sends the drive assistance status to the EMB controller, which performs coordinated control during continuous slip control. EMB sends the ABS status of the four wheels to the reference vehicle speed module, and the wheel-side drive motor controller sends the actual drive torque to the reference vehicle speed module.

[0168] Corresponding to the above-described method for determining reference vehicle speed, this application also provides a device for determining reference vehicle speed. Figure 8 This is a schematic diagram of a reference vehicle speed determination device provided in an embodiment of this application, as shown below. Figure 8 As shown in the figure, this embodiment provides a reference vehicle speed determination device, which includes:

[0169] The first determining module 801 is used to determine a drive assistance strategy and a target drive torque when the vehicle is in a wheel speed distortion state; wherein, the drive assistance strategy is used to determine the target wheel to be driven and assisted.

[0170] The sending module 802 is used to send the target driving torque to the wheel-side drive motor controller of the target wheel, so that the wheel-side drive motor controller can use the target driving torque to drive the target wheel, so that the target wheel enters an approximately pure rolling state with a slip ratio close to 0.

[0171] The second determining module 803 is used to acquire the speed of the four wheels of the vehicle after drive assistance is applied, and to determine the target reference speed based on the speed of the four wheels.

[0172] In an optional implementation, the first determining module 801 is further configured to:

[0173] When all four wheels of a vehicle are under anti-lock braking control, if the vehicle meets any one of the following three conditions, it is determined that the vehicle is in a state of wheel speed distortion. The three conditions include: steering condition, duration condition, and slip ratio condition.

[0174] Among them, the steering condition is that the longitudinal acceleration is opposite to the direction of vehicle movement and the duration of lateral acceleration - yaw rate * longitudinal speed > 0 is greater than the first preset duration;

[0175] The duration condition is that the duration during which all four wheels are under anti-lock braking control exceeds the second preset duration;

[0176] The slip ratio condition is that the duration for which the minimum longitudinal slip ratio of the four wheels exceeds the first preset threshold exceeds the third preset duration.

[0177] In one optional implementation, the drive assistance strategy includes a single-sided drive strategy and a diagonal drive strategy. The single-sided drive strategy refers to a control strategy that applies drive assistance to the front and rear wheels on the same side of the turn, based on the vehicle's oversteer direction. The diagonal drive strategy refers to a control strategy that alternates between applying drive assistance to the left front and right rear wheels as one group and the right front and left rear wheels as another group. The first determining module 801, when determining the drive assistance strategy, is specifically used for:

[0178] If the vehicle meets the duration or slip ratio conditions, the drive assistance strategy is determined to be a diagonal drive strategy.

[0179] If the vehicle meets the steering requirements, the drive assist strategy is determined to be a one-sided drive strategy.

[0180] In an optional implementation, after all four wheels of the vehicle have entered anti-lock braking control, the first determining module 801 is further configured to:

[0181] Obtain the current vehicle status parameters, and determine whether the vehicle is in a malfunctioning state based on the current vehicle status parameters;

[0182] Accordingly, if a vehicle meets any one of the following three conditions, it is determined that the vehicle is in a state of wheel speed distortion, including:

[0183] If the vehicle is not in a malfunctioning state and meets any one of the following three conditions, then the vehicle is determined to be in a state of wheel speed distortion.

[0184] In one alternative implementation, the sending module 802 is specifically used for:

[0185] Determine whether the target actuator corresponding to the target wheel is in a faulty state;

[0186] If the target actuator corresponding to the target wheel is not in a fault state, the target drive torque is sent to the wheel-side drive motor controller of the target wheel.

[0187] In one optional implementation, the first determining module 801, when determining the target driving torque, is specifically used for:

[0188] Obtain the current road surface adhesion coefficient;

[0189] A target mapping table corresponding to the drive assistance strategy is determined, and at least one drive assistance strategy corresponds one-to-one with at least one mapping table; wherein, the mapping table is used to indicate the correspondence between multiple road surface adhesion coefficients and multiple drive torques;

[0190] The target driving torque is determined based on the current road surface adhesion coefficient and target mapping relationship table.

[0191] In an optional implementation, after determining the drive assistance strategy and the target drive torque, the first determining module 801 is further configured to:

[0192] The wheel speed synchronization execution request is sent to the electromechanical brake controller so that when the electromechanical brake controller receives the wheel speed synchronization execution request, it freezes the feedforward torque term and clears the feedback torque to zero when performing slip ratio closed-loop control and calculating braking torque for the target wheel. The wheel speed synchronization execution request includes the identification information corresponding to the target wheel.

[0193] In one optional implementation, when determining the target reference vehicle speed based on the four wheel speeds, the second determining module 803 is specifically used for:

[0194] The maximum wheel speed of the target wheel or the maximum speed among the four wheels is used as the maximum limit for the target reference vehicle speed;

[0195] Determine the target reference speed based on the speed of the four wheels and the maximum limit.

[0196] The reference vehicle speed determination device provided in this embodiment can execute the method provided in the above method embodiment. Its implementation principle and technical effect are similar, and will not be described in detail here.

[0197] Figure 9 A schematic diagram of the structure of the electronic device provided in this application. Figure 9 As shown, the electronic device 90 provided in this embodiment includes at least one processor 901 and a memory 902. Optionally, the device 90 further includes a communication component 903. The processor 901, memory 902, and communication component 903 are connected via a bus 904.

[0198] In a specific implementation, at least one processor 901 executes computer execution instructions stored in memory 902, causing at least one processor 901 to perform the above-described method.

[0199] The specific implementation process of processor 901 can be found in the above method embodiments, and its implementation principle and technical effect are similar. It will not be repeated here.

[0200] In the above embodiments, it should be understood that the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in this invention can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor.

[0201] The memory may include random access memory (RAM) and may also include non-volatile memory (NVM), such as at least one disk storage device.

[0202] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of illustration, the buses shown in the accompanying drawings are not limited to a single bus or a single type of bus.

[0203] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the above-described method.

[0204] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the above-described method.

[0205] The aforementioned readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. The readable storage medium can be any available medium accessible to a general-purpose or special-purpose computer.

[0206] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can reside in an Application Specific Integrated Circuit (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components in the device.

[0207] The division of units is merely a logical functional division; 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 indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0208] 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.

[0209] In addition, the functional units in the various embodiments of the present invention 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.

[0210] If a function 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, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, 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 steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0211] Those skilled in the art will understand that all or part of the steps of the above-described method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0212] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A method for determining a reference vehicle speed, characterized in that, The method includes: When the vehicle is in a state of wheel speed distortion, a drive assistance strategy and a target drive torque are determined; wherein, the drive assistance strategy is used to determine the target wheel to be driven and assisted. The target driving torque is sent to the wheel-side drive motor controller of the target wheel, so that the wheel-side drive motor controller uses the target driving torque to drive the target wheel, so that the target wheel enters an approximately pure rolling state with a slip ratio close to 0. The vehicle acquires the speeds of its four wheels after drive assistance is applied, and determines the target reference speed based on these four wheel speeds.

2. The method according to claim 1, characterized in that, The method further includes: When all four wheels of the vehicle are under anti-lock braking control, if the vehicle meets any one of the following three conditions, the vehicle is determined to be in a wheel speed distortion state, wherein the three conditions include: steering condition, duration condition, and slip ratio condition. Among them, the steering condition is that the longitudinal acceleration is opposite to the direction of vehicle movement and the duration of lateral acceleration - yaw rate * longitudinal speed > 0 is greater than the first preset duration; The duration condition is that the duration during which all four wheels are under anti-lock braking control exceeds the second preset duration; The slip ratio condition is that the duration for which the minimum longitudinal slip ratio of the four wheels exceeds the first preset threshold exceeds the third preset duration.

3. The method according to claim 2, characterized in that, The drive assistance strategy includes a single-sided drive strategy and a diagonal drive strategy. The single-sided drive strategy refers to a control strategy that applies drive assistance to the front and rear wheels on the same side of the turn, based on the vehicle's oversteer direction. The diagonal drive strategy refers to a control strategy that alternates between applying drive assistance to the two groups of diagonally opposite wheels, with the left front wheel and right rear wheel forming one group and the right front wheel and left rear wheel forming another. Determining the drive assistance strategy includes: If the vehicle meets the duration condition or the slip ratio condition, then the drive assistance strategy is determined to be a diagonal drive strategy. If the vehicle meets the steering conditions, then the drive assistance strategy is determined to be a one-sided drive strategy.

4. The method according to claim 2, characterized in that, After all four wheels of the vehicle have entered anti-lock braking control, the method further includes: Obtain the current vehicle status parameters, and determine whether the vehicle is in a functional abnormal state based on the current vehicle status parameters; Accordingly, if the vehicle meets any one of the following three conditions, the vehicle is determined to be in a state of wheel speed distortion, including: If the vehicle is not in a malfunctioning state and the vehicle meets any one of the following three conditions, then the vehicle is determined to be in a wheel speed distortion state.

5. The method according to claim 1, characterized in that, Sending the target drive torque to the wheel-side drive motor controller of the target wheel includes: Determine whether the target actuator corresponding to the target wheel is in a fault state; If the target actuator corresponding to the target wheel is not in a fault state, the target drive torque is sent to the wheel-side drive motor controller of the target wheel.

6. The method according to any one of claims 1-5, characterized in that, Determine the target drive torque, including: Obtain the current road surface adhesion coefficient; A target mapping table corresponding to the drive assistance strategy is determined, and at least one drive assistance strategy corresponds one-to-one with at least one mapping table; wherein, the mapping table is used to indicate the correspondence between multiple road surface adhesion coefficients and multiple drive torques; The target driving torque is determined based on the current road surface adhesion coefficient and target mapping relationship table.

7. The method according to claim 1, characterized in that, After determining the drive assistance strategy and the target drive torque, the method further includes: The wheel speed synchronization execution request is sent to the electromechanical brake controller so that when the electromechanical brake controller receives the wheel speed synchronization execution request, it freezes the feedforward torque term and clears the feedback torque to zero when performing slip ratio closed-loop control and calculating braking torque for the target wheel. The wheel speed synchronization execution request includes the identification information corresponding to the target wheel.

8. The method according to any one of claims 1-5, characterized in that, Based on the speeds of the four wheels, determine the target reference vehicle speed, including: The maximum wheel speed of the target wheel or the maximum speed among the four wheels is used as the maximum limit for the target reference vehicle speed; The target reference vehicle speed is determined based on the speeds of the four wheels and the maximum value limit.

9. A reference vehicle speed determination device, characterized in that, The device includes: The first determining module is used to determine a drive assistance strategy and a target drive torque when the vehicle is in a wheel speed distortion state; wherein, the drive assistance strategy is used to determine the target wheel to be driven and assisted. The sending module is used to send the target driving torque to the wheel-side drive motor controller of the target wheel, so that the wheel-side drive motor controller can use the target driving torque to drive the target wheel, so that the target wheel enters an approximately pure rolling state with a slip ratio close to 0. The second determining module is used to acquire the speed of the four wheels of the vehicle after drive assistance is applied, and to determine the target reference speed based on the speed of the four wheels.

10. An electronic device, characterized in that, include: Memory, processor; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory, causing the processor to perform the method as described in any one of claims 1-8.

11. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1-8.

12. A computer program product, characterized in that, Includes a computer program that, when executed by a processor, implements the method described in any one of claims 1-8.

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