Vehicle driving anti-skid control method and system, vehicle and storage medium

Abstract

The invention discloses a vehicle driving anti-skid control method and system, a vehicle and a storage medium, and belongs to the technical field of vehicles. The method is applied to a control system comprising a vehicle control unit, an anti-lock braking system, a motor controller and a motor, and is realized through the following steps that the anti-lock braking system detects the vehicle speed of four wheel ends in real time and sends the vehicle speed to a CAN bus; the vehicle control unit calculates basic driving torque and judges whether the vehicle enters a slipping state or not based on the wheel speed information; if it is judged that slipping occurs, the torque limiting coefficient is determined according to the slipping severity, and the limited final driving torque is calculated and output to a motor controller to be executed. According to an existing vehicle control unit and a vehicle-mounted network, special hardware does not need to be added, and low-cost and high-integration-level driving anti-skid control is achieved. The system is simple in structure and rapid in response, slipping can be actively inhibited from the source, and the driving safety and stability of the vehicle on a low-adhesion road surface and the durability of a transmission system are improved through multi-stage hierarchical control and false triggering prevention criteria.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of vehicles, and particularly relates to a vehicle driving anti-slip control method, a control system, a vehicle and a storage medium. BACKGROUND

[0002] With the enhancement of global environmental protection consciousness and the rapid development of new energy vehicle technology, electric vehicles, especially pure electric commercial vehicles and passenger vehicles, have a broad market development prospect. Electric vehicles are usually driven by electric motors directly or through a transmission system, and have the advantages of fast torque response and smooth output. However, in low adhesion road conditions (such as icy and snowy roads, wet roads) or sudden acceleration conditions, the driving wheels are prone to slip due to excessive torque, and the driving wheel slip not only causes loss of vehicle power and decline in driving stability, but also may cause impact on the differential, half shaft and other transmission parts due to excessive speed difference between the two driving wheels, and even long-term mechanical damage (such as rear axle fracture), which seriously affects the safety and reliability of the vehicle.

[0003] Currently, vehicle anti-slip control mainly relies on traditional anti-lock braking system (ABS) or traction control system (TCS). ABS is mainly used to prevent wheel lock during braking; TCS is usually applied to engine vehicles, and the wheel speed difference between the driving wheels and the non-driving wheels is monitored, and the driving wheels are braked to reduce the engine torque to suppress excessive slip of the driving wheels. However, for the characteristics of pure electric vehicles, directly applying the traditional TCS scheme has the following limitations: first, the traditional TCS system often needs additional wheel speed sensors and independent control modules, and the system cost is high; second, its control logic is mostly designed based on the torque adjustment characteristics of the engine of a fuel vehicle, and the matching degree with the fast and accurate response characteristics of the electric motor is not high; at the same time, some simple anti-slip strategies may not be able to distinguish different degrees of slip conditions, and the control is too rough, which affects the power performance if the intervention is too early, and cannot effectively prevent slip if the intervention is too late. In addition, in specific scenarios such as vehicle hub test, the wheels may be in a state of static (vehicle speed is zero) and the electric motor is idling, and the simple speed difference judgment logic is easy to trigger the anti-slip control by mistake, which interferes with normal testing.

[0004] Therefore, there is a need for a driving anti-slip control scheme that is fast in response and accurate in control. SUMMARY

[0005] The present application provides a vehicle driving anti-slip control method, a control system, a vehicle and a storage medium, which solve at least one of the above technical problems.

[0006] The technical scheme adopted by the present application is as follows: A vehicle driving anti-slip control method applied to a control system comprising a vehicle controller, an anti-lock system, a motor controller and a motor, the method comprising: S1. The anti-lock braking system detects the speed information of the four wheels of the vehicle in real time and sends the speed information to the CAN bus; S2. The vehicle controller calculates the basic driving torque according to the accelerator pedal opening degree; S3. The vehicle controller determines whether the vehicle enters the driving wheel slip state according to the speed information obtained from the CAN bus; S4. If it is determined that the slip state exists, the vehicle controller determines the corresponding driving torque limiting coefficient and calculates the final driving torque based on the basic driving torque and the driving torque limiting coefficient; S5. The vehicle controller sends the final driving torque to the motor controller; S6. The motor controller controls the torque output of the motor according to the final driving torque.

[0007] As an optional embodiment, in S3, determining whether the vehicle enters the driving wheel slip state specifically includes: calculating the speed difference ΔV between the maximum value Vmax and the minimum value Vmin of the speed information of the four wheels at the current time, ΔV = Vmax - Vmin; comparing the speed difference ΔV with the preset speed difference threshold value for entering the anti-slip control, and determining whether the minimum value Vmin is zero; If the speed difference ΔV is greater than or equal to the speed difference threshold value, and the minimum value Vmin is not zero, and the duration exceeds the first time threshold value, it is determined that the vehicle enters the driving wheel slip state.

[0008] As an optional embodiment, in S4, according to different slip severity, the corresponding driving torque limiting coefficient is determined, specifically including: There are at least two different anti-slip control stages, each stage corresponding to different speed difference threshold values and driving torque limiting coefficients; When the speed difference ΔV reaches or exceeds the speed difference threshold value of the nth stage, the nth stage anti-slip control is entered, and the driving torque limiting coefficient corresponding to the stage is applied, wherein Kn is a value between 0 and 1, and Kn decreases as n increases.

[0009] As an optional embodiment, the anti-slip control stage includes three stages: When ΔV> the first speed difference threshold value, the first stage of anti-slip control is entered, and the driving torque limiting coefficient is the first coefficient K1; When ΔV> the second speed difference threshold value, the second stage of anti-slip control is entered, and the driving torque limiting coefficient is the second coefficient K2; When ΔV > third speed difference threshold value, enter anti-slip three-stage control, and the driving torque limiting coefficient is the third coefficient K3; Wherein, third speed difference threshold value > second speed difference threshold value > first speed difference threshold value, and 0 < K3 < K2 < K1 < 1.

[0010] As an optional embodiment, the S4 further comprises a condition judgment for exiting the anti-slip control: In the anti-slip control state, the speed difference ΔV is continuously monitored; If the speed difference ΔV is less than a speed difference threshold value for exiting the anti-slip control, and the minimum value Vmin is not zero, and the state lasts more than a second time threshold value, it is determined that the vehicle is out of the slipping state; After determining that the vehicle is out of the slipping state, the driving torque limiting coefficient is restored to 1.

[0011] As an optional embodiment, in the S2, the base driving torque is calculated by the vehicle controller according to the accelerator pedal opening degree and the current vehicle speed through a table lookup method.

[0012] As an optional embodiment, in the S4, the calculation formula of the final driving torque is: final driving torque = base driving torque × driving torque limiting coefficient.

[0013] The present application also includes a vehicle driving anti-slip control system for implementing the method as described above, and the system comprises: An anti-lock braking system configured to detect the four wheel end speeds of the vehicle in real time, and send the wheel end speed information to the CAN bus; A vehicle controller configured to: Obtain the wheel end speed information from the CAN bus; Calculate the base driving torque according to the accelerator pedal opening degree; Judge whether the vehicle enters the driving wheel slipping state according to the four wheel end speeds, and determine the driving torque limiting coefficient when the slipping is determined; Calculate the final driving torque based on the base driving torque and the driving torque limiting coefficient, and send the final driving torque through the CAN bus; A motor controller configured to receive the final driving torque instruction from the vehicle controller, and control the motor to output the corresponding torque.

[0014] The present application also includes a vehicle comprising the vehicle driving anti-slip control system as described above.

[0015] The present application also includes a computer readable storage medium having a computer program stored thereon, which is executed by a processor to implement the vehicle driving anti-slip control method as described above.

[0016] By adopting the technical scheme, the application has the beneficial effects: Through the cooperative control of the vehicle controller, the anti-lock system, the motor controller and the CAN bus, closed-loop control of vehicle driving anti-slip is realized, the existing core electronic control units (vehicle controller VCU, anti-lock system ABS, motor controller MCU) and the standard vehicle network (CAN bus) are utilized, no special hardware sensor or independent controller is needed, high integration of the anti-slip function is realized, and the system complexity and cost are reduced.

[0017] The vehicle controller (VCU) can process wheel speed information and driver torque request in real time and directly intervene in driving torque. In combination with the fast and accurate response of the motor controller (MCU) to the motor torque, accurate dynamic suppression of the driving wheel slip is realized, and the control real-time performance is improved.

[0018] According to the wheel end state, the driving torque output is actively limited, which is a kind of active control strategy of “prevention first”. Compared with the traditional way of torque redistribution through braking after the slip occurs, the application directly limits the torque from the power source (motor), which can more effectively reduce the probability and degree of slip occurrence and protect the transmission system from impact.

[0019] The scheme decomposes the anti-slip control into multiple steps to form standardized software function modules. It is convenient for development, debugging and integration in different vehicle platforms and electric vehicle projects, and has good universality. BRIEF DESCRIPTION OF DRAWINGS

[0020] The accompanying drawings, which are included to provide a further understanding of the application and constitute a part of this application, illustrate certain illustrative embodiments of the application and together with the description serve to explain the application. In the drawings: Figure 1 The control method flow chart in an embodiment of the application. DETAILED DESCRIPTION

[0021] In order to more clearly explain the overall concept of the application, the following will be described in detail with reference to the accompanying drawings.

[0022] In the following description, many specific details are set forth in order to provide a thorough understanding of the application, but the application can also be practiced without the other ways different from those described herein, therefore, the scope of protection of the application is not limited by the specific embodiments disclosed below. It should be noted that the embodiments of the application and the features in each embodiment can be combined with each other without conflict.

[0023] In addition, in the description of the present application, it should be understood that the terms "top", "bottom", "inner", "outer", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0024] In the present application, unless specifically defined and limited otherwise, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection, or communication; it can be directly connected, or indirectly connected through intermediate medium, or internal communication of two elements or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0025] In the present application, unless specifically defined and limited otherwise, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact between the first and second features through an intermediate medium. In the description of the specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples.

[0026] The present application provides a vehicle driving anti-slip control method, as shown in the accompanying drawings, applied to a control system comprising a vehicle controller, an anti-lock system, a motor controller and a motor, the method comprising: Figure 1 As shown in the accompanying drawings, applied to a control system comprising a vehicle controller, an anti-lock system, a motor controller and a motor, the method comprising: S1. The anti-lock system detects the vehicle speed information of the four wheel ends of the vehicle in real time, and sends the vehicle speed information to the CAN bus; S2. The vehicle controller calculates the basic driving torque according to the accelerator pedal opening degree; S3. The vehicle controller determines whether the vehicle enters the driving wheel slip state according to the vehicle speed information obtained from the CAN bus; S4. If it is determined that the slip state, the vehicle controller determines the corresponding driving torque limiting coefficient, and calculates the final driving torque based on the basic driving torque and the driving torque limiting coefficient; S5. The vehicle controller sends the final driving torque to the motor controller; S6. The motor controller controls the torque output of the motor according to the final driving torque.

[0027] Through the cooperative control of the vehicle controller, the anti-lock system, the motor controller and the CAN bus, the closed-loop control of the vehicle driving anti-slip is realized, the existing core electric control units (the vehicle controller VCU, the anti-lock system ABS and the motor controller MCU) and the standard vehicle network (the CAN bus) are utilized, no special hardware sensor or independent controller needs to be added, the high integration of the anti-slip function is realized, and the system complexity and cost are reduced.

[0028] The vehicle controller (VCU) can process the wheel speed information and the driver torque request in real time and directly intervene in the driving torque. In combination with the fast and accurate response of the motor controller (MCU) to the motor torque, the accurate dynamic suppression of the driving wheel slip is realized, and the control real-time performance is improved.

[0029] According to the active restriction of the driving torque output according to the wheel end state, it is a kind of active control strategy of “prevention first”. Compared with the traditional way of torque redistribution through braking after the slip occurs, the present application directly limits the torque from the power source (the motor), which can more effectively reduce the probability and degree of slip and protect the transmission system from impact.

[0030] The present scheme decomposes the anti-slip control into multiple steps to form standardized software function modules. It is convenient for development, debugging and integration in different vehicle platforms and electric vehicle projects, and has good universality.

[0031] In one embodiment, in S3, it is judged whether the vehicle enters the driving wheel slip state, specifically comprising: calculating the speed difference AV between the maximum value Vmax and the minimum value Vmin of the speed information of the four wheel ends at the current moment, AV = Vmax - Vmin; comparing the speed difference AV with the preset speed difference threshold value of entering the anti-slip control, and judging whether the minimum value Vmin is zero; if the speed difference AV is greater than or equal to the speed difference threshold value, the minimum value Vmin is not zero, and the duration exceeds the first time threshold value, it is determined that the vehicle enters the driving wheel slip state.

[0032] By setting the multiple conditions of AV ≥ speed difference threshold value, Vmin ≠ 0 and the duration of such state as the criterion for entering the anti-slip state, the accuracy of state recognition is improved, wherein Vmin ≠ 0 can effectively avoid the false judgment of the vehicle in the non-running conditions such as the hub test and the lifting rack due to the single wheel being stationary, and ensures the reliability of the control.

[0033] As an optional embodiment, in S4, the corresponding driving torque limiting coefficient is determined according to different slip severity, specifically including: There are at least two different anti-slip control stages, each stage corresponding to a different speed difference threshold and a driving torque limiting coefficient; When the speed difference ΔV reaches or exceeds the speed difference threshold of the nth stage, the nth stage anti-slip control is entered, and the driving torque limiting coefficient corresponding to the stage Kn is applied, where Kn is a value between 0 and 1, and Kn decreases as n increases.

[0034] Further, the anti-slip control stage includes three stages: When ΔV> the first speed difference threshold, the first stage of anti-slip control is entered, and the driving torque limiting coefficient is the first coefficient K1; When ΔV> the second speed difference threshold, the second stage of anti-slip control is entered, and the driving torque limiting coefficient is the second coefficient K2; When ΔV> the third speed difference threshold, the third stage of anti-slip control is entered, and the driving torque limiting coefficient is the third coefficient K3; Wherein, the third speed difference threshold > the second speed difference threshold > the first speed difference threshold, and 0 < K3 < K2 < K1 < 1.

[0035] By setting multi-stage anti-slip control and associating different speed difference thresholds with torque limiting coefficients, the slip severity is managed in stages. When the slip is mild, the torque is moderately limited to maintain power, and when the slip is severe, the torque is greatly reduced to ensure safety, avoiding one-size-fits-all rough intervention, while ensuring anti-slip effect, optimizing driving smoothness and power experience.

[0036] In an embodiment, S4 further includes a condition judgment for exiting anti-slip control: While in the anti-slip control state, the speed difference ΔV is continuously monitored; If the speed difference ΔV is less than a speed difference threshold for exiting anti-slip control, and the minimum value Vmin is not zero, and the state lasts more than a second time threshold, it is determined that the vehicle has exited the slip state; After determining that the slip state has been exited, the driving torque limiting coefficient is restored to 1.

[0037] Through the judgment condition for exiting anti-slip control, the control system can smoothly exit the intervention state according to the recovery of the road adhesion condition, and return the torque control to the driver, ensuring that the system only works when necessary, avoiding excessive control of the vehicle power and the driver's driving.

[0038] In S2, the base driving torque is calculated by the vehicle controller according to the accelerator pedal opening and the current vehicle speed through table lookup method.

[0039] The table lookup method is used to calculate the basic driving torque, which is mature, reliable and fast in response, and can accurately obtain the torque demand of the driver according to the accelerator pedal opening and the current vehicle speed, thereby providing an accurate reference for subsequent anti-slip torque correction.

[0040] In S4, the calculation formula of the final driving torque is: final driving torque = basic driving torque x driving torque limiting coefficient.

[0041] The final driving torque is calculated through simple multiplication, and the calculation method is simple and efficient, has low requirements on the operation resources of the controller, is easy to implement in the real vehicle controller, and ensures the real-time performance and reliability of the system.

[0042] The application also includes a vehicle driving anti-slip control system for implementing the method as described above, and the system comprises: An anti-lock braking system configured to detect the vehicle speeds of the four wheel ends of the vehicle in real time, and send the wheel end speed information to the CAN bus; A vehicle control unit configured to: Obtain the wheel end speed information from the CAN bus; Calculate the basic driving torque according to the accelerator pedal opening; Determine whether the vehicle enters the driving wheel slip state according to the four wheel end speeds, and determine the driving torque limiting coefficient when the slip is determined; Calculate the final driving torque based on the basic driving torque and the driving torque limiting coefficient, and send the final driving torque through the CAN bus; A motor controller configured to receive the final driving torque instruction from the vehicle control unit, and control the motor to output a corresponding torque.

[0043] The application also includes a vehicle comprising the vehicle driving anti-slip control system as described above.

[0044] The application also includes a computer readable storage medium having a computer program stored thereon, which is executed by a processor to implement the vehicle driving anti-slip control method of any one of the above.

[0045] The application does not describe the places that can be implemented by using or referring to the existing technology.

[0046] Each embodiment in the specification is described in a progressive manner, and the same or similar parts between each embodiment can be referred to each other, and each embodiment mainly describes the differences from other embodiments.

[0047] The above merely provides an example of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application should be included in the scope of claims of the present application.

Claims

1. A vehicle drive slip control method, characterized by, The method is applied to a control system comprising a vehicle controller, an anti-lock braking system, a motor controller and a motor, and comprises the following steps: S1. The anti-lock braking system detects the speed information of the four wheels in real time and sends the speed information to a CAN bus; S2. The vehicle controller calculates a basic driving torque according to the opening degree of an accelerator pedal; S3. The vehicle controller determines whether the vehicle enters a driving wheel slip state according to the speed information obtained from the CAN bus; S4. If it is determined that the vehicle enters the slip state, the vehicle controller determines a corresponding driving torque limiting coefficient and calculates a final driving torque based on the basic driving torque and the driving torque limiting coefficient; S5. The vehicle controller sends the final driving torque to the motor controller; S6. The motor controller controls the torque output of the motor according to the final driving torque.

2. The vehicle drive slip control method according to claim 1, characterized by, In S3, determining whether the vehicle enters the driving wheel slip state specifically comprises: calculating the speed difference ΔV between the maximum value Vmax and the minimum value Vmin of the speed information of the four wheels at the current time, ΔV = Vmax - Vmin; comparing the speed difference ΔV with a preset speed difference threshold value for entering the anti-slip control and determining whether the minimum value Vmin is zero; if the speed difference ΔV is greater than or equal to the speed difference threshold value and the minimum value Vmin is not zero and the duration exceeds a first time threshold value, it is determined that the vehicle enters the driving wheel slip state.

3. The vehicle drive slip control method according to claim 2, characterized by, In S4, the corresponding driving torque limiting coefficient is determined according to different slip severities, specifically comprising: there are at least two different anti-slip control stages, each stage corresponding to different speed difference threshold values and driving torque limiting coefficients; when the speed difference ΔV reaches or exceeds the speed difference threshold value of the nth stage, the vehicle enters the nth stage of anti-slip control and the driving torque limiting coefficient corresponding to the stage is applied, wherein Kn is a value between 0 and 1, and Kn decreases as n increases.

4. The vehicle drive slip control method according to claim 3, characterized by, The anti-slip control stage includes three stages: when ΔV > the first speed difference threshold value, the vehicle enters the first stage of anti-slip control and the driving torque limiting coefficient is the first coefficient K1; when ΔV > the second speed difference threshold value, the vehicle enters the second stage of anti-slip control and the driving torque limiting coefficient is the second coefficient K2; when ΔV > the third speed difference threshold value, the vehicle enters the third stage of anti-slip control and the driving torque limiting coefficient is the third coefficient K3; wherein the third speed difference threshold value > the second speed difference threshold value > the first speed difference threshold value, and 0 < K3 < K2 < K1 < 1.

5. The vehicle drive slip control method according to claim 2 or 3, characterized by, S4 also includes the condition judgment for exiting the anti-slip control: in the anti-slip control state, the speed difference ΔV is continuously monitored; if the speed difference ΔV is less than a speed difference threshold value for exiting the anti-slip control and the minimum value Vmin is not zero and the state lasts for more than a second time threshold value, it is determined that the vehicle exits the slip state; after it is determined that the vehicle exits the slip state, the driving torque limiting coefficient is restored to 1.

6. The vehicle drive slip control method according to claim 1, characterized by, In S2, the vehicle controller calculates the basic driving torque by table lookup method according to the opening degree of the accelerator pedal and the current vehicle speed.

7. The vehicle drive slip control method according to claim 1, characterized by, In the S4, the final driving torque is calculated according to the formula: final driving torque = basic driving torque × driving torque limiting coefficient.

8. A vehicle drive slip control system characterized by, The system is used to implement the method of any one of claims 1-7, and comprises: An anti-lock braking system configured to detect the speeds of the four wheels of the vehicle in real time and send the wheel speed information to a CAN bus; A vehicle control unit configured to: Obtain the wheel speed information from the CAN bus; Calculate a basic driving torque according to the accelerator pedal opening; Determine whether the vehicle is in a driving wheel slip state according to the speeds of the four wheels, and determine a driving torque limiting coefficient when the slip is determined; Calculate a final driving torque based on the basic driving torque and the driving torque limiting coefficient, and send the final driving torque through the CAN bus; A motor control unit configured to receive the final driving torque instruction from the vehicle control unit and control the motor to output a corresponding torque.

9. A vehicle characterized by comprising: The vehicle driving anti-slip control system of claim 8.

10. A computer-readable storage medium having stored thereon a computer program, characterized in that, The program is executed by a processor to implement the vehicle driving anti-slip control method of any one of claims 1-7.

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