Method and system for controlling traction force of vehicle body in snowfield driving state

Abstract

The invention discloses a method and system for controlling the traction force of a vehicle body in a snowfield driving state, and the method comprises the steps that an ESC control module monitors the parameter information of the vehicle in the driving state through a sensor, and obtains a rolling resistance coefficient through calculation of a calculation module; the ESC control module judges the running state of the vehicle and judges whether the vehicle is in a deep snow running state or not, if yes, the road surface is calibrated, the slip rate offset is generated, and the ESC control module sends the slip rate offset to the traction force control module to adjust the output size of the traction force of the vehicle; through a calculation module, parameter information detected and collected by an ESC control module is calculated to obtain a rolling resistance coefficient, the slip rate offset is adjusted according to the change of the rolling resistance coefficient, and the slip rate offset is sent to a traction force control system to adjust the output of traction force. The control precision of the traction control system on a deep snow road surface can be improved, and the vehicle running speed is increased.

Description

Technical Field

[0001] This invention relates to the field of automotive braking control technology, and in particular to a method and control system for controlling vehicle traction in snowy driving conditions. Background Technology

[0002] With the continuous development of vehicle electrification, precise vehicle control has become increasingly important. Existing traction control methods cannot quickly identify the characteristics of deep snow roads, resulting in excessive torque reduction in deep snow conditions. Consequently, the traction control system cannot accurately control the output traction force, causing the vehicle to move slowly.

[0003] Patent CN109080623B discloses a snow driving control system for a hybrid electric vehicle. The main control unit receives a snow mode activation signal generated when a snow mode switch is triggered, and controls the vehicle to enter snow mode. In snow mode, it sends a snow mode request signal to the sub-control unit. The TCU responds to the snow mode request signal by controlling the vehicle's gear shifting timing to match the powertrain's operating state. The ESP responds to the snow mode request signal by controlling the vehicle to shorten its braking distance and initiating a torque reduction request. The EAS responds to the snow mode request signal by lowering the suspension height. This method improves the stability of the vehicle's chassis control by reducing torque, but it still results in inaccurate control of the vehicle's traction output during snow driving, making it difficult to flexibly adjust the vehicle's speed in snowy conditions. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a vehicle traction control method and control system for driving in snowy conditions.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a method for controlling vehicle traction in snow driving conditions, comprising:

[0006] S1: The ESC control module monitors the parameter information of the vehicle's driving status through sensors and calculates the rolling resistance coefficient through the calculation module;

[0007] S2: Based on the rolling resistance coefficient, determine the vehicle's driving status and whether the vehicle is driving in deep snow. If yes, calibrate the road surface and generate a slip ratio offset. If no, return to step S1 to continue monitoring.

[0008] S3: The ESC control module sends the slip ratio offset to the traction control module and activates the deep snow mode flag. The traction control module adjusts the output of the vehicle's traction force according to the slip ratio offset.

[0009] As a further description of the above technical solution: In step S1, the method further includes:

[0010] S11: The ESC control module acquires the current vehicle driving torque and vehicle braking torque, and monitors the current vehicle acceleration and gradient values ​​through sensors;

[0011] S12: Calculate the vehicle rolling resistance coefficient using the calculation module, and obtain a more accurate rolling resistance coefficient through the recursive least squares method.

[0012] As a further description of the above technical solution: the method by which the calculation module calculates the rolling resistance coefficient is as follows: Ma=(T1 / R)-(T2 / R)-(Mα)-(kMG);

[0013] Where M is the vehicle mass, a is the vehicle acceleration, T1 is the vehicle driving torque, T2 is the vehicle braking torque, R is the tire radius, α is the slope value, k is the rolling resistance coefficient, and G is the gravitational acceleration.

[0014] As a further description of the above technical solution: In step S2, the following is also included:

[0015] S21: The ESC control module judges the vehicle's driving status. When the vehicle speed is less than the first threshold, the accelerator pedal opening is greater than the second threshold, the rolling resistance coefficient is less than the third threshold, and the vehicle is in forward gear, it is determined that the vehicle is in deep snow driving status.

[0016] S22: If the vehicle is driving in deep snow, calibrate the road surface, generate a table of rolling resistance coefficient and slip ratio offset, and output the slip ratio offset.

[0017] As a further description of the above technical solution: the first threshold is 8.3 m / s, the second threshold is 15°, and the third threshold is 0.3.

[0018] As a further description of the above technical solution: In step S3, the following is also included:

[0019] S31: The traction control module receives the slip ratio offset, increases the traction output, and generates a deep snow mode indicator signal;

[0020] S32: The deep snow mode flag bit is activated by receiving the deep snow mode flag signal and provides a reminder through the flag.

[0021] As a further description of the above technical solution: when driving in deep snow, the rolling resistance coefficient is in the range of 0.03-0.3, and the slip ratio offset is less than 0.1.

[0022] As a further description of the above technical solution: the sensor is a six-axis sensor.

[0023] It also includes a vehicle traction control system for driving in snowy conditions, wherein the control system is applicable to the control method described in any of the above technical solutions, including:

[0024] The ESC control module monitors parameter information of the vehicle's driving status and collects vehicle acceleration and gradient values.

[0025] The calculation module calculates the rolling resistance coefficient based on the vehicle design parameters and the collected monitoring parameters, and sends it to the ESC control module to generate the slip ratio offset.

[0026] The driving judgment module calibrates the vehicle road surface based on the calculated rolling resistance coefficient to determine whether the vehicle is driving in deep snow.

[0027] The traction control module receives the slip ratio offset and performs traction control based on the slip ratio offset when the vehicle is driving in deep snow.

[0028] As a further description of the above technical solution: the calculation module fits the calculated rolling resistance coefficient using the least recursive squares method.

[0029] The above technical solution has the following advantages or beneficial effects:

[0030] 1. The calculation module calculates the rolling resistance coefficient by analyzing the parameter information detected and collected by the ESC control module. The slip ratio offset is adjusted according to the change of the rolling resistance coefficient, and the slip ratio offset is sent to the traction control system to adjust the traction output. This can improve the control accuracy of the traction control system on deep snow roads and increase the vehicle speed. Attached Figure Description

[0031] Figure 1 The flow chart of the control method proposed in this invention Figure 1 ;

[0032] Figure 2 The flow chart of the control method proposed in this invention Figure 2 ;

[0033] Figure 3 The flow chart of the control method proposed in this invention Figure 3 ;

[0034] Figure 4 The flow chart of the control method proposed in this invention Figure 4 ;

[0035] Figure 5This is a schematic diagram of the control system proposed in this invention.

[0036] Legend:

[0037] 1. ESC control module; 2. Calculation module; 3. Driving judgment module; 4. Traction control module. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] Reference Figure 1 One embodiment of the present invention provides a method for controlling vehicle traction in snow driving conditions, comprising:

[0040] S1: The ESC control module monitors the parameter information of the vehicle's driving status through sensors and calculates the rolling resistance coefficient through the calculation module;

[0041] S2: Based on the rolling resistance coefficient, determine the vehicle's driving status and whether the vehicle is driving in deep snow. If yes, calibrate the road surface and generate a slip ratio offset. If no, return to step S1 to continue monitoring.

[0042] S3: The ESC control module sends the slip ratio offset to the traction control module and activates the deep snow mode flag. The traction control module adjusts the output of the vehicle's traction force according to the slip ratio offset.

[0043] In this embodiment, the ESC control module monitors and collects parameter information of the vehicle's driving state through sensors. The sensors are six-axis sensors, which collect raw acceleration signals through IMU signals and process them to obtain the current slope value and vehicle acceleration. Specifically, the six-axis sensor includes a three-axis gyroscope and a three-axis accelerometer, which can monitor the slope value and acceleration of the vehicle's current driving state. The traction control module obtains the vehicle's current total driving torque and total braking torque, and the calculation module calculates the rolling resistance coefficient. The rolling resistance coefficient is fitted using the least recursive square method to obtain a more accurate rolling resistance coefficient. The module also judges the vehicle's driving state. When the vehicle is driving in deep snow, a slip ratio offset is generated and input into the traction control module. The larger the rolling resistance coefficient, the larger the slip ratio offset. When the traction control module is active, it adjusts the traction force according to the slip ratio offset to control and adjust the traction force, thereby increasing the vehicle's driving speed.

[0044] Reference Figure 2 In step S1, the method further includes:

[0045] S11: The ESC control module acquires the current vehicle driving torque and braking torque, and monitors the current vehicle acceleration and gradient values ​​through sensors;

[0046] S12: Calculate the vehicle rolling resistance coefficient using the calculation module, and obtain a more accurate rolling resistance coefficient through the recursive least squares method.

[0047] In this embodiment, the ESC control module is an electronic stability control system for automobiles. During the braking process, the system obtains the driving torque and braking torque of the vehicle based on the changes in vehicle acceleration. It also monitors the vehicle acceleration and gradient values ​​under the driving state through a six-axis sensor to calculate the rolling resistance coefficient of the vehicle. The calculated rolling resistance coefficient is then fitted using the recursive least squares method, and coefficients with large deviations are removed to obtain a more accurate rolling resistance coefficient.

[0048] Specifically, the calculation module calculates the rolling resistance coefficient using the following formula:

[0049] Ma=(T1 / R)-(T2 / R)-(Mα)-(kMG);

[0050] Where M is the vehicle mass, a is the vehicle acceleration, T1 is the vehicle driving torque, T2 is the vehicle braking torque, R is the tire radius, α is the slope value, k is the rolling resistance coefficient, and G is the gravitational acceleration.

[0051] In this embodiment, the vehicle mass M, tire radius R, and gravitational acceleration G are all basic constants that can be obtained from the original vehicle design parameters. The vehicle driving torque T1 and vehicle braking torque T2 can be obtained by the traction control module, and the slope value α and vehicle acceleration a are obtained by the sensor signals built into the ESC control module.

[0052] Reference Figure 3 In step S2, the following is also included:

[0053] S21: The ESC control module judges the vehicle's driving status. When the vehicle speed is less than the first threshold, the accelerator pedal opening is greater than the second threshold, the rolling resistance coefficient is less than the third threshold, and the vehicle is in forward gear, it is determined that the vehicle is in deep snow driving status.

[0054] S22: If the vehicle is driving in deep snow, calibrate the road surface, generate a table of rolling resistance coefficient and slip ratio offset, and output the slip ratio offset.

[0055] Specifically, the first threshold is 8.3 m / s, the second threshold is 15°, and the third threshold is 0.3.

[0056] In this embodiment, the vehicle's driving state is determined. If the vehicle is driving in deep snow, the following conditions must be met: vehicle speed less than 8.3 m / s, accelerator pedal opening greater than 15°, and the vehicle in drive gear. It can be determined that after applying a certain angle of accelerator, the vehicle speed remains low, the rolling resistance coefficient is less than 0.3, and there is a slip ratio offset. This indicates that the vehicle is slipping during driving. In deep snow, the rolling resistance coefficient ranges from 0.03 to 0.3, and the slip ratio offset is less than 0.1. The generated table of rolling resistance coefficient and slip ratio offset is shown in Table 1.

[0057] Rolling resistance coefficient 0.03 0.1 0.2 0.3 slip ratio offset 0 0.03 0.05 0.1

[0058] Table 1

[0059] Table 1 shows the slip ratio offset corresponding to the calculated rolling resistance coefficient. The rolling resistance coefficient will have different values ​​on different road surfaces. In this embodiment, the rolling resistance coefficient under deep snow driving conditions is between 0.03 and 0.3. The corresponding slip ratio offset can be obtained based on the actual monitored values.

[0060] Reference Figure 4 In step S3, the following is also included:

[0061] S31: The traction control module receives the slip ratio offset, increases the traction output, and generates a deep snow mode indicator signal;

[0062] S32: The deep snow mode flag is activated by receiving the deep snow mode flag signal and provides a reminder via the flag.

[0063] In this embodiment, the traction control module receives the slip ratio offset and adjusts the magnitude of the vehicle's traction force to increase the vehicle's speed. When the received slip ratio offset is large, the vehicle speed is low, and the traction control module increases the output traction force. When the slip ratio offset is small, the traction control module can reduce the output traction force. A deep snow mode indicator signal is also generated and sent to the deep snow mode flag bit for activation, causing the deep snow mode flag bit to illuminate as a warning.

[0064] Reference Figure 5 The present invention also provides an embodiment of a vehicle traction control system for driving in snowy conditions. The control system is applicable to any of the control methods described above, including:

[0065] ESC control module 1 monitors the parameter information of the vehicle's driving status and collects the vehicle's acceleration and gradient values;

[0066] Calculation module 2 calculates the rolling resistance coefficient based on the vehicle design parameters and the collected monitoring parameters, and sends it to ESC control module 1 to generate slip ratio offset.

[0067] The driving judgment module 3 calibrates the vehicle road surface based on the calculated rolling resistance coefficient to determine whether it is a deep snow driving condition;

[0068] Traction control module 4 receives slip ratio offset and performs traction control based on slip ratio offset when the vehicle is driving in deep snow.

[0069] Specifically, the calculation module 2 fits the calculated rolling resistance coefficient using the least recursive squares method.

[0070] In this embodiment, the ESC control module 1 collects parameter information during vehicle driving by monitoring sensors to obtain vehicle acceleration and gradient values. The calculation module 2 calculates the rolling resistance coefficient and fits it using the recursive least squares method to improve the accuracy of the rolling resistance coefficient. The driving judgment module 3 calibrates the road surface to determine whether the vehicle is driving in deep snow. If the vehicle is driving in deep snow, the slip ratio offset corresponding to the road surface is obtained and sent to the traction control module 4 to control the magnitude of the traction output and adjust the vehicle speed on the deep snow road surface.

[0071] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for controlling vehicle traction in snow driving conditions, characterized in that, include: S1: The ESC control module monitors the parameter information of the vehicle's driving status through sensors and calculates the rolling resistance coefficient through the calculation module; S2: Based on the rolling resistance coefficient, determine the vehicle's driving status and whether the vehicle is driving in deep snow. If yes, calibrate the road surface and generate a slip ratio offset. If no, return to step S1 to continue monitoring. S3: The ESC control module sends the slip ratio offset to the traction control module and activates the deep snow mode flag. The traction control module adjusts the output of the vehicle's traction force according to the slip ratio offset.

2. The vehicle traction control method under snow driving conditions according to claim 1, characterized in that: Step S1 further includes: S11: The ESC control module acquires the current vehicle driving torque and vehicle braking torque, and monitors the current vehicle acceleration and gradient values ​​through sensors; S12: Calculate the vehicle rolling resistance coefficient using the calculation module, and obtain a more accurate rolling resistance coefficient through the recursive least squares method.

3. The method for controlling vehicle traction in snow driving conditions according to claim 1, characterized in that: The calculation module calculates the rolling resistance coefficient using the following formula: Ma=(T1 / R)-(T2 / R)-(Mα)-(kMG); Where M is the vehicle mass, a is the vehicle acceleration, T1 is the vehicle driving torque, T2 is the vehicle braking torque, R is the tire radius, α is the slope value, k is the rolling resistance coefficient, and G is the gravitational acceleration.

4. The method for controlling vehicle traction in snow driving conditions according to claim 1, characterized in that: Step S2 further includes: S21: The ESC control module judges the vehicle's driving status. When the vehicle speed is less than the first threshold, the accelerator pedal opening is greater than the second threshold, the rolling resistance coefficient is less than the third threshold, and the vehicle is in forward gear, it is determined that the vehicle is in deep snow driving status. S22: If the vehicle is driving in deep snow, calibrate the road surface, generate a table of rolling resistance coefficient and slip ratio offset, and output the slip ratio offset.

5. The method for controlling vehicle traction in snow driving conditions according to claim 4, characterized in that: The first threshold is 8.3 m / s, the second threshold is 15°, and the third threshold is 0.

3.

6. The method for controlling vehicle traction in snow driving conditions according to claim 1, characterized in that: Step S3 further includes: S31: The traction control module receives the slip ratio offset, increases the traction output, and generates a deep snow mode indicator signal; S32: The deep snow mode flag bit is activated by receiving the deep snow mode flag signal and provides a reminder through the flag.

7. The method for controlling vehicle traction in snow driving conditions according to claim 1, characterized in that: When driving in deep snow, the rolling resistance coefficient ranges from 0.03 to 0.3, and the slip ratio offset is less than 0.

1.

8. The method for controlling vehicle traction in snow driving conditions according to claim 1, characterized in that: The sensor is a six-axis sensor.

9. A vehicle traction control system for driving in snowy conditions, characterized in that, The control system is applicable to the control method described in any one of claims 1-8, comprising: The ESC control module (1) monitors the parameter information of the vehicle under driving conditions and collects the vehicle acceleration and slope values. The calculation module (2) calculates the rolling resistance coefficient based on the vehicle design parameters and the collected monitoring parameters and sends it to the ESC control module (1) to generate the slip ratio offset. The driving judgment module (3) calibrates the vehicle road surface based on the calculated rolling resistance coefficient and determines whether it is a deep snow driving state; The traction control module (4) receives the slip ratio offset and performs traction control based on the slip ratio offset when the vehicle is driving in deep snow.

10. A vehicle traction control system for driving in snow as described in claim 9, characterized in that: The calculation module (2) fits the calculated rolling resistance coefficient using the least recursive squares method.

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