Torque control intervention opportunity calculation method for preventing vehicle from slipping

Abstract

The invention discloses a torque control intervention opportunity calculation method for preventing a vehicle from slipping, which comprises the following steps of: determining slip and a threshold according to the wheel speed of each wheel, the opening degree of an accelerator pedal and the opening degree of a brake pedal; the slip and threshold are corrected according to the obtained wheel acceleration, and a slip and threshold primary correction value is obtained; according to the vehicle sensing parameters, the slip and threshold primary correction value is determined to be corrected again, and a slip and threshold secondary correction value is obtained; determining the slip sum of the driving wheels according to the wheel speed of each wheel; and when the slip sum of the driving wheel is greater than the slip sum threshold secondary correction value, the torque control is intervened. Advanced intervention of the torque control function is achieved, and tire slipping and insufficient / excessive steering can be effectively avoided.

Description

Technical Field

[0001] The present invention relates to the field of vehicle control, and in particular to a method for calculating torque control intervention timing for preventing a vehicle from slipping. Background Art

[0002] At present, electric vehicles have a higher and higher market share. High horsepower and fast acceleration are the main technical highlights of electric vehicles. However, the problem is that electric vehicles are more likely to have drive slippage than fuel vehicles, especially those equipped with low rolling resistance tires or rear-wheel drive vehicles. When accelerating, wheels are more likely to slip. This problem will cause the vehicle to lose driving force seriously when accelerating in a straight line, and will cause understeer or oversteer when turning.

[0003] The existing mainstream technical solutions are mainly divided into two categories, TCS traction control and VDC yaw control. The traditional TCS drive torque control method is mainly based on the wheel speed slip difference between the driving wheel and the non-driving wheel. When the slip difference exceeds the set threshold, the TCS function is triggered to adjust the drive torque. The shortcomings of this method are: it will only intervene in the adjustment when the front and rear wheel speed difference is relatively large, which may easily cause the driving wheel to slip significantly and the driving adhesion to be lost; in addition, it is easy to cause setbacks during driving. The VDC yaw control method triggers VDC adjustment when a large yaw difference occurs during the vehicle's turning process. The torque adjustment is mainly manifested as driving torque limitation. The shortcomings of this method are that the adjustment timing is too late. The vehicle will only intervene in the adjustment when there is obvious yaw, relatively large understeer or oversteer. There are obvious deficiencies in the control of vehicle safety and comfort.

[0004] The main shortcoming of the above two solutions is that the intervention timing is too late, resulting in adjustments being made only when the vehicle becomes significantly unstable. Summary of the invention

[0005] The object of the present invention is to provide a method for calculating the timing of torque control intervention for preventing vehicle lateral deviation, so as to achieve early adjustment of the driving torque and prevent the vehicle from skidding.

[0006] In order to solve the above technical problems, the present invention provides a technical solution: a method for calculating the torque control intervention timing to prevent vehicle slippage, comprising:

[0007] Determine the slip and threshold based on the wheel speed, accelerator pedal opening, and brake pedal opening of each wheel;

[0008] Correcting the slip and threshold according to the acquired wheel acceleration to obtain a first correction value of the slip and threshold;

[0009] According to the vehicle sensing parameters, it is determined that the first correction values ​​of slip and threshold are corrected again to obtain the second correction values ​​of slip and threshold;

[0010] Determine the driving wheel slip and the wheel speed according to the wheel speed of each wheel;

[0011] When the driving wheel slip is greater than the slip threshold secondary correction value, the torque control is intervened.

[0012] According to the above scheme, the method for determining the slip and threshold according to the wheel speed, accelerator pedal opening, and brake pedal opening of each wheel includes:

[0013] Determine the reference vehicle speed according to the wheel speed of the non-driving wheel;

[0014] The slip and threshold are determined based on the accelerator pedal opening, brake pedal opening and reference vehicle speed.

[0015] According to the above scheme, the method for determining the reference vehicle speed according to the wheel speed of the non-driving wheel includes:

[0016] The average of the wheel speeds of the two non-driven wheels is taken as the reference vehicle speed.

[0017] According to the above scheme, the method for determining the slip and threshold according to the accelerator pedal opening, the brake pedal opening, and the reference vehicle speed includes:

[0018] Only when the accelerator pedal opening is greater than the set threshold and the brake pedal mark is invalid, the threshold trigger judgment is performed and the slip and threshold are output;

[0019] The slip and threshold are determined based on the comparison between the reference vehicle speed and the set threshold.

[0020] According to the above scheme, the method of correcting the slip and threshold according to the acquired wheel acceleration to obtain the first correction value of the slip and threshold includes:

[0021] The wheel acceleration is compared with the set threshold, and the slip and threshold are multiplied by a certain percentage based on the comparison result. The result is the primary correction value of the slip and threshold.

[0022] According to the above scheme, the method for determining to correct the first correction value of slip and threshold again according to the vehicle sensor parameters to obtain the second correction value of slip and threshold includes:

[0023] When the set yaw conditions are met, the yaw ratio is determined;

[0024] According to the yaw ratio, the correction factor is determined;

[0025] According to the correction coefficient, the first correction values ​​of slip and threshold are corrected again to obtain the second correction values ​​of slip and threshold.

[0026] According to the above scheme, when the following conditions are met at the same time, it is considered that the yaw condition is met:

[0027] 1) The steering wheel angle is greater than a certain angle value;

[0028] 2) The accelerator pedal opening is greater than a certain opening value;

[0029] 3) The reference vehicle speed is greater than a certain speed;

[0030] The reference vehicle speed is the average of the wheel speeds of the two non-driven wheels.

[0031] According to the above scheme, the method for determining the yaw ratio includes:

[0032] Determine the actual turning radius based on vehicle speed and yaw rate;

[0033] Determine the driver's expected turning radius based on the vehicle stability factor, distance between the front and rear axles, vehicle speed, and steering wheel angle;

[0034] Determine the transient yaw ratio of a sampling period according to the actual turning radius of the sampling period and the turning radius expected by the driver;

[0035] The yaw ratio of the current sampling period is determined according to the transient yaw ratios of several consecutive sampling periods.

[0036] According to the above scheme, the method for determining the correction coefficient according to the yaw ratio includes:

[0037] The yaw ratio is compared with a set threshold value, and a correction coefficient is determined according to the comparison result;

[0038] The method of re-correcting the slip and threshold primary correction values ​​according to the correction coefficient to obtain the slip and threshold secondary correction values ​​includes:

[0039] Multiply the correction coefficient by the slip and threshold primary correction value to obtain the slip and threshold secondary correction value.

[0040] According to the above scheme, the method for determining the driving wheel slip sum according to the wheel speed of each wheel includes:

[0041] Determine the drive wheel slip sum based on the left drive wheel speed, the right drive wheel speed, and the reference vehicle speed.

[0042] The beneficial effects of the present invention are: by collecting various parameters during vehicle driving, the slip and threshold secondary correction value and the driving wheel slip sum are obtained, and when the driving wheel slip sum is greater than the slip and threshold secondary correction value, the torque control is intervened, and the intervention timing of the torque control function is clarified. The method makes full use of the existing sensor elements of the vehicle, saving material costs, and the method can adjust the driving torque in advance before the vehicle has a large front and rear slip difference and obvious understeer / oversteer, thus realizing preventive control. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 The present invention is a flowchart of a method for calculating the torque control intervention timing for preventing vehicle slipping according to an embodiment of the present invention. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0045] Embodiment 1:

[0046] This embodiment provides a method for calculating a torque control intervention timing for preventing a vehicle from slipping, comprising the following steps:

[0047] S1. Determine the slip and threshold according to the wheel speed, accelerator pedal opening, and brake pedal opening of each wheel;

[0048] Step S1 includes the following steps:

[0049] S101, determining a reference vehicle speed according to the wheel speed of the non-driving wheel;

[0050] The reference vehicle speed is expressed as Veh_Spd_Ref, which is the average of the wheel speeds of the two non-driven wheels;

[0051] S102, determining a slip and a threshold according to an accelerator pedal opening, a brake pedal opening, and a reference vehicle speed;

[0052] Only when the accelerator pedal opening Acc_Pdl is greater than the set threshold (5% in this embodiment) and the brake pedal flag is invalid (BLS_Flg=0) is satisfied at the same time, the threshold triggering judgment is performed, and the slip and threshold are output;

[0053] The output rules of slip and threshold are shown in Table 1:

[0054] Table 1

[0055]

[0056] The design principle of Table 1 is: the higher the vehicle speed, the more dangerous the skidding is, and the lower the intervention threshold is set;

[0057] S2. Correcting the slip and threshold according to the acquired wheel acceleration to obtain a first correction value of the slip and threshold;

[0058] It should be understood that the wheel acceleration Whl_Acc is mainly obtained by calculating the wheel speed in unit time, and the wheel speed is obtained by a wheel speed sensor. In this embodiment, the unit time is defined as 10ms.

[0059] When Whl_Acc>5m / s 2 , and Whl_Acc≤10m / s 2 ,lip_THR=Slip_THR_b×80%;

[0060] When Whl_Acc>10m / s 2 When, Slip_THR=Slip_THR_b×60%;

[0061] Among them, Slip_THR is the slip and threshold correction value;

[0062] It should be understood that the greater the wheel acceleration, the earlier intervention is needed and the lower the intervention threshold;

[0063] S3. According to the vehicle sensing parameters, determine to correct the slip and threshold primary correction values ​​again to obtain slip and threshold secondary correction values;

[0064] S301, when the set yaw working condition is met, determining the yaw ratio;

[0065] The yaw condition is considered to be met when the following conditions are met at the same time:

[0066] 1) Steering wheel angle δ>10deg;

[0067] 2) Accelerator pedal opening Acc_Pdl>20%;

[0068] 3) Reference vehicle speed Veh_Spd>20km / h;

[0069] The yaw ratio calculation process is as follows:

[0070] Firstly, the actual turning radius and the driver's expected turning radius within a certain sampling period are determined, and the transient yaw ratio of the sampling period is obtained;

[0071]

[0072] Among them, R rl is the actual turning radius, V is the vehicle speed, ω R is the yaw angular velocity, R dr is the turning radius expected by the driver, K is the vehicle stability factor, L is the distance between the front and rear axles, and δ is the steering wheel angle; K and L are both design parameters of the vehicle, which are determined during vehicle design and are known quantities, and δ is measured by the steering wheel angle sensor;

[0073] Then, the average value of the instantaneous yaw ratios of the current sampling period and several previous continuous sampling periods (in this embodiment, 5 sampling periods are selected to calculate the average value) is taken as the yaw ratio of the current sampling period;

[0074]

[0075] I[k] represents the instantaneous yaw ratio of the kth sampling period, R rl [k], R dr [k] represents the actual turning radius and the driver's expected turning radius in the kth sampling period, respectively;

[0076] In this embodiment, the time interval between adjacent sampling periods is 10ms;

[0077] S302, determining a correction coefficient according to the yaw ratio;

[0078] The relationship between the correction coefficient and the yaw ratio is shown in Table 2:

[0079] Table 2

[0080]

[0081] The numerical design of the correction coefficient τ is mainly based on the yaw ratio Different and different; yaw ratio When the steering is neutral, no correction is needed, so the correction coefficient τ is designed to be 1; in addition, when the steering is over, the vehicle is at risk of losing control, and the degree of danger is high; therefore, the intervention threshold needs to be adjusted to a lower level; for understeering, it is mainly when the turning radius is too large when passing a curve; when turning at a small angle, there is a certain amount of understeering, and the degree of danger is low. Therefore, the threshold is adjusted less;

[0082] S303, correcting the slip and threshold primary correction values ​​again according to the correction coefficient to obtain slip and threshold secondary correction values;

[0083] S4, determining the driving wheel slip sum according to the wheel speed of each wheel;

[0084] Slip_Spd_SumSpd_FL_Spd_FR_Veh_Spd_Ref

[0085] In the above formula, Slip_Spd_Sum is the driving wheel slip sum, Spd_FL and Spd_FR are the wheel speeds of the left driving wheel, and Spd_FR is the wheel speed of the right driving wheel;

[0086] S5. When the driving wheel slip is greater than the slip threshold secondary correction value, the torque control is intervened.

[0087] It should be understood that the purpose of the present invention is to determine the timing of intervention in torque control. There are many existing methods for the torque control function, which are not part of the invention of the present invention and will not be described in detail here.

[0088] Embodiment 2:

[0089] In order to implement the method for calculating the torque control intervention timing for preventing vehicle skidding described in the first embodiment, this embodiment discloses a torque control intervention timing calculation device for preventing vehicle skidding, comprising:

[0090] The slip and threshold calculation module is used to determine the slip and threshold according to the wheel speed, accelerator pedal opening, and brake pedal opening of each wheel;

[0091] A first slip and threshold correction module, used to correct the slip and threshold according to the acquired wheel acceleration to obtain a slip and threshold primary correction value;

[0092] A second slip and threshold correction module is used to determine to correct the slip and threshold primary correction values ​​again according to the vehicle sensor parameters to obtain the slip and threshold secondary correction values;

[0093] The torque control intervention timing judgment module is used to intervene in the torque control when the driving wheel slip is greater than the slip threshold secondary correction value.

[0094] Embodiment three:

[0095] The present embodiment provides a computer device, such as a smart phone, tablet computer, laptop computer, desktop computer, rack server, blade server, tower server or cabinet server (including an independent server or a server cluster composed of multiple servers) that can execute programs. The computer device of the present embodiment includes at least but is not limited to: a memory and a processor that can communicate with each other through a system bus.

[0096] In this embodiment, the memory (i.e., readable storage medium) includes flash memory, hard disk, multimedia card, card-type memory (e.g., SD or DX memory, etc.), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM). The memory may also be an external storage device of a computer device, such as a plug-in hard disk equipped on the computer device, a smart memory card (SmartMedia Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), etc. Of course, the memory may also include both the internal storage unit of the computer device and its external storage device. In this embodiment, the memory is generally used to store the operating system and various application software installed on the computer device, such as the program code of the torque control intervention timing calculation method for preventing vehicle slipping in the first embodiment. In addition, the memory may also be used to temporarily store various data that have been output or are to be output.

[0097] In some embodiments, the processor may be a central processing unit (CPU), a controller, a microcontroller, a microprocessor, or other data processing chip. The processor is generally used to control the overall operation of the computer device. In this embodiment, the processor is used to run the program code stored in the memory or process data, such as running the program code of the torque control intervention timing calculation method for preventing vehicle slippage, so as to implement the torque control intervention timing calculation method for preventing vehicle slippage in the first embodiment.

[0098] Embodiment 4:

[0099] The present application also provides a computer-readable storage medium, such as a flash memory, a hard disk, a multimedia card, a card-type memory (e.g., an SD or DX memory, etc.), a random access memory (RAM), a static random access memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a programmable read-only memory (PROM), a magnetic memory, a disk, an optical disk, a server, an App application store, etc., on which a computer program is stored, and the program realizes corresponding functions when executed by a processor. The computer-readable storage medium of this embodiment is used to store the program code of the method for calculating the torque control intervention timing to prevent vehicle slippage, and when executed by the processor, the method for calculating the torque control intervention timing to prevent vehicle slippage in the first embodiment is realized.

[0100] Embodiment five:

[0101] This embodiment provides a car, the car comprising:

[0102] A device for calculating the timing of torque control intervention to prevent the vehicle from skidding;

[0103] Torque control device.

[0104] The torque control intervention timing calculation device for preventing the vehicle from slipping includes:

[0105] The slip and threshold calculation module is used to determine the slip and threshold according to the wheel speed, accelerator pedal opening, and brake pedal opening of each wheel;

[0106] A first slip and threshold correction module, used to correct the slip and threshold according to the acquired wheel acceleration to obtain a slip and threshold primary correction value;

[0107] A second slip and threshold correction module is used to determine to correct the slip and threshold primary correction values ​​again according to the vehicle sensor parameters to obtain the slip and threshold secondary correction values;

[0108] The torque control intervention timing judgment module is used to intervene in the torque control when the driving wheel slip is greater than the slip threshold secondary correction value.

[0109] It can be understood that the torque control device determines its own intervention timing based on the output of the torque control intervention timing calculation device for preventing the vehicle from slipping.

[0110] According to the above scheme, the method for determining the slip and threshold according to the wheel speed, accelerator pedal opening, and brake pedal opening of each wheel includes:

[0111] Determine the reference vehicle speed according to the wheel speed of the non-driving wheel;

[0112] The slip and threshold are determined based on the accelerator pedal opening, brake pedal opening and reference vehicle speed.

[0113] According to the above scheme, the method for determining the reference vehicle speed according to the wheel speed of the non-driving wheel includes:

[0114] The average of the wheel speeds of the two non-driven wheels is taken as the reference vehicle speed.

[0115] Furthermore, the method for determining the slip and threshold according to the accelerator pedal opening, the brake pedal opening, and the reference vehicle speed includes:

[0116] Only when the accelerator pedal opening is greater than the set threshold and the brake pedal mark is invalid, the threshold trigger judgment is performed and the slip and threshold are output;

[0117] The slip and threshold are determined based on the comparison between the reference vehicle speed and the set threshold.

[0118] Furthermore, the method of correcting the slip and the threshold according to the acquired wheel acceleration to obtain the first correction value of the slip and the threshold includes:

[0119] The wheel acceleration is compared with the set threshold, and the slip and threshold are multiplied by a certain percentage based on the comparison result. The result is the primary correction value of the slip and threshold.

[0120] Furthermore, the method of determining to correct the first correction value of slip and threshold again according to the vehicle sensing parameters to obtain the second correction value of slip and threshold includes:

[0121] When the set yaw conditions are met, the yaw ratio is determined;

[0122] According to the yaw ratio, the correction factor is determined;

[0123] According to the correction coefficient, the first correction values ​​of slip and threshold are corrected again to obtain the second correction values ​​of slip and threshold.

[0124] Furthermore, when the following conditions are met at the same time, it is considered that the yaw condition is met:

[0125] 1) The steering wheel angle is greater than a certain angle value;

[0126] 2) The accelerator pedal opening is greater than a certain opening value;

[0127] 3) The reference vehicle speed is greater than a certain speed;

[0128] The reference vehicle speed is the average of the wheel speeds of the two non-driven wheels.

[0129] According to the above scheme, the method for determining the yaw ratio includes:

[0130] Determine the actual turning radius based on vehicle speed and yaw rate;

[0131] Determine the driver's expected turning radius based on the vehicle stability factor, distance between the front and rear axles, vehicle speed, and steering wheel angle;

[0132] Determine the transient yaw ratio of a sampling period according to the actual turning radius of the sampling period and the turning radius expected by the driver;

[0133] The yaw ratio of the current sampling period is determined according to the transient yaw ratios of several consecutive sampling periods.

[0134] Furthermore, the method for determining the correction coefficient according to the yaw ratio includes:

[0135] The yaw ratio is compared with a set threshold value, and a correction coefficient is determined according to the comparison result;

[0136] The method of re-correcting the slip and threshold primary correction values ​​according to the correction coefficient to obtain the slip and threshold secondary correction values ​​includes:

[0137] Multiply the correction coefficient by the slip and threshold primary correction value to obtain the slip and threshold secondary correction value.

[0138] Furthermore, the method for determining the driving wheel slip sum according to the wheel speed of each wheel includes:

[0139] Determine the drive wheel slip sum based on the left drive wheel speed, the right drive wheel speed, and the reference vehicle speed.

[0140] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for calculating the timing of torque control intervention to prevent vehicle slippage, characterized in that: include: Determine the slip and threshold based on the wheel speed, accelerator pedal opening, and brake pedal opening of each wheel; Correcting the slip and threshold according to the acquired wheel acceleration to obtain a first correction value of the slip and threshold; According to the vehicle sensing parameters, it is determined that the first correction values ​​of slip and threshold are corrected again to obtain the second correction values ​​of slip and threshold; Determine the driving wheel slip and the wheel speed according to the wheel speed of each wheel; When the driving wheel slip is greater than the slip threshold secondary correction value, the torque control is intervened.

2. The method for calculating the torque control intervention timing for preventing vehicle slipping according to claim 1, characterized in that: The method for determining the slip and threshold according to the wheel speed, accelerator pedal opening, and brake pedal opening of each wheel includes: Determine the reference vehicle speed according to the wheel speed of the non-driving wheel; The slip and threshold are determined based on the accelerator pedal opening, brake pedal opening and reference vehicle speed.

3. The method for calculating the torque control intervention timing for preventing vehicle slipping according to claim 2, characterized in that: The method for determining the reference vehicle speed according to the wheel speed of the non-driving wheel includes: The average of the wheel speeds of the two non-driven wheels is taken as the reference vehicle speed.

4. The method for calculating the torque control intervention timing for preventing vehicle slipping according to claim 2, characterized in that: The method for determining the slip and threshold according to the accelerator pedal opening, the brake pedal opening, and the reference vehicle speed includes: Only when the accelerator pedal opening is greater than the set threshold and the brake pedal mark is invalid, the threshold trigger judgment is performed and the slip and threshold are output; The slip and threshold are determined based on the comparison between the reference vehicle speed and the set threshold.

5. The method for calculating the torque control intervention timing for preventing vehicle slipping according to claim 1, characterized in that: The method of correcting the slip and the threshold according to the acquired wheel acceleration to obtain the first correction value of the slip and the threshold includes: The wheel acceleration is compared with the set threshold, and the slip and threshold are multiplied by a certain percentage based on the comparison result. The result is the primary correction value of the slip and threshold.

6. The method for calculating the torque control intervention timing for preventing vehicle slipping according to claim 1, characterized in that: The method of determining to correct the first correction value of slip and threshold again according to the vehicle sensing parameters to obtain the second correction value of slip and threshold includes: When the set yaw conditions are met, the yaw ratio is determined; According to the yaw ratio, the correction factor is determined; According to the correction coefficient, the first correction values ​​of slip and threshold are corrected again to obtain the second correction values ​​of slip and threshold.

7. The method for calculating the torque control intervention timing for preventing vehicle slipping according to claim 6, characterized in that: The yaw condition is considered to be met when the following conditions are met at the same time: 1) The steering wheel angle is greater than a certain angle value; 2) The accelerator pedal opening is greater than a certain opening value; 3) The reference vehicle speed is greater than a certain speed; The reference vehicle speed is the average of the wheel speeds of the two non-driven wheels.

8. The method for calculating the torque control intervention timing for preventing vehicle slipping according to claim 6, characterized in that: The method for determining the yaw ratio comprises: Determine the actual turning radius based on vehicle speed and yaw rate; Determine the driver's expected turning radius based on the vehicle stability factor, distance between the front and rear axles, vehicle speed, and steering wheel angle; Determine the transient yaw ratio of a sampling period according to the actual turning radius of the sampling period and the turning radius expected by the driver; The yaw ratio of the current sampling period is determined according to the transient yaw ratios of several consecutive sampling periods.

9. The method for calculating the torque control intervention timing for preventing vehicle slipping according to claim 6, characterized in that: The method for determining the correction coefficient according to the yaw ratio includes: The yaw ratio is compared with a set threshold value, and a correction coefficient is determined according to the comparison result; The method of re-correcting the slip and threshold primary correction values ​​according to the correction coefficient to obtain the slip and threshold secondary correction values ​​includes: Multiply the correction coefficient by the slip and threshold primary correction value to obtain the slip and threshold secondary correction value.

10. The method for calculating the torque control intervention timing for preventing vehicle slipping according to claim 3, characterized in that: The method for determining the driving wheel slip sum according to the wheel speed of each wheel comprises: Determine the drive wheel slip sum based on the left drive wheel speed, the right drive wheel speed, and the reference vehicle speed.

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