CN109910850B - Vehicle and brake control method and device thereof - Google Patents

Vehicle and brake control method and device thereof Download PDF

Info

Publication number
CN109910850B
CN109910850B CN201711332637.0A CN201711332637A CN109910850B CN 109910850 B CN109910850 B CN 109910850B CN 201711332637 A CN201711332637 A CN 201711332637A CN 109910850 B CN109910850 B CN 109910850B
Authority
CN
China
Prior art keywords
wheel
target wheel
cylinder pressure
brake
threshold value
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201711332637.0A
Other languages
Chinese (zh)
Other versions
CN109910850A (en
Inventor
姚伟
王世友
陈双龙
秦凯莉
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fudi Power Co ltd
Original Assignee
BYD Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by BYD Co Ltd filed Critical BYD Co Ltd
Priority to CN201711332637.0A priority Critical patent/CN109910850B/en
Priority to PCT/CN2018/120594 priority patent/WO2019114752A1/en
Publication of CN109910850A publication Critical patent/CN109910850A/en
Application granted granted Critical
Publication of CN109910850B publication Critical patent/CN109910850B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/17—Using electrical or electronic regulation means to control braking
    • B60T8/1755—Brake regulation specially adapted to control the stability of the vehicle, e.g. taking into account yaw rate or transverse acceleration in a curve
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/17—Using electrical or electronic regulation means to control braking
    • B60T8/176—Brake regulation specially adapted to prevent excessive wheel slip during vehicle deceleration, e.g. ABS
    • B60T8/1761—Brake regulation specially adapted to prevent excessive wheel slip during vehicle deceleration, e.g. ABS responsive to wheel or brake dynamics, e.g. wheel slip, wheel acceleration or rate of change of brake fluid pressure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/17—Using electrical or electronic regulation means to control braking
    • B60T8/176—Brake regulation specially adapted to prevent excessive wheel slip during vehicle deceleration, e.g. ABS
    • B60T8/1764—Regulation during travel on surface with different coefficients of friction, e.g. between left and right sides, mu-split or between front and rear
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
    • B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition

Landscapes

  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Regulating Braking Force (AREA)

Abstract

The invention discloses a vehicle and a brake control method and a brake control device thereof, wherein the brake control method comprises the following steps: when the vehicle enters a braking state, judging the slip rate of a target wheel; when the slip ratio of the target wheel is larger than a first slip ratio threshold value or smaller than a second slip ratio threshold value, obtaining the pressure of a brake master cylinder of the vehicle, and judging whether the pressure of the brake master cylinder is larger than the first pressure threshold value or not in real time, wherein the second slip ratio threshold value is smaller than the first slip ratio threshold value; if the pressure of the brake master cylinder is greater than the first pressure threshold value, timing the time that the pressure of the brake master cylinder is continuously greater than the first pressure threshold value; when the timing time does not reach a first preset time, controlling the brake wheel cylinder pressure of the target wheel according to a first braking force difference threshold value; and after the timing time reaches a first preset time, controlling the brake wheel cylinder pressure of the target wheel according to a second braking force difference threshold value, wherein the first braking force difference threshold value is smaller than the second braking force difference threshold value.

Description

Vehicle and brake control method and device thereof
Technical Field
The present invention relates to the field of vehicle control technologies, and in particular, to a method for controlling braking of a vehicle, a non-transitory computer-readable storage medium, a device for controlling braking of a vehicle, and a vehicle.
Background
With the continuous improvement of the running speed of automobiles and the increase of the road running density, higher and higher requirements are also put forward on the running safety of automobiles. The anti-lock braking system of the automobile can prevent the wheel from slipping during braking by controlling and adjusting the braking force of the wheel, and improve the direction stability during braking, thereby greatly improving the braking performance of the automobile and improving the safety of the automobile.
When the tire characteristics of the left wheel and the right wheel of the automobile are different or the road adhesion coefficients contacted by the left wheel and the right wheel of the automobile are different, a yaw moment can be generated due to uneven stress of the tires in the braking process under the condition, so that the automobile often sideslips and deviates in emergency braking, the serious yaw of the automobile is caused, and the operation psychological burden of a driver is increased. Therefore, maintaining directional stability of the emergency brake of the vehicle is critical to driving safety.
At present, in order to solve the above problems, the related art recognizes the road surface to determine the above situation and takes corresponding measures when the above situation is determined. However, when the road surface recognition function cannot recognize the difference in road surface adhesion coefficient between the left and right wheels, the effect of limiting the yaw moment by the above-described measures is insufficient, and the lateral stability of the vehicle at the time of braking is poor. In addition, in the initial stage of different road surface adhesion coefficients of the left and right wheels, the driver often has insufficient response to sudden change of driving conditions, and cannot timely take effective measures such as steering wheel adjustment of vehicle direction and the like.
Disclosure of Invention
The present invention is directed to solving, at least to some extent, one of the technical problems in the art described above. To this end, an object of the present invention is to provide a brake control method for a vehicle, which can ensure braking performance and an anti-lock effect of the vehicle and can further improve lateral stability of the vehicle when braking.
A second object of the invention is to propose a non-transitory computer-readable storage medium.
A third object of the present invention is to provide a brake control apparatus for a vehicle.
A fourth object of the invention is to propose a vehicle.
In order to achieve the above object, an embodiment of a first aspect of the present invention provides a braking control method for a vehicle, including: judging the slip rate of a target wheel when the vehicle enters a braking state; when the slip ratio of the target wheel is larger than a first slip ratio threshold value or smaller than a second slip ratio threshold value, acquiring the pressure of a brake master cylinder of the vehicle, and judging whether the pressure of the brake master cylinder is larger than the first pressure threshold value or not in real time, wherein the second slip ratio threshold value is smaller than the first slip ratio threshold value; if the brake master cylinder pressure is greater than the first pressure threshold, timing the time that the brake master cylinder pressure is continuously greater than the first pressure threshold; when the timing time does not reach a first preset time, controlling the brake wheel cylinder pressure of the target wheel according to a first braking force difference threshold value; and after the timing time reaches the first preset time, controlling the brake wheel cylinder pressure of the target wheel according to a second braking force difference threshold value, wherein the first braking force difference threshold value is smaller than the second braking force difference threshold value.
According to the brake control method of the vehicle of the embodiment of the invention, when the vehicle enters the braking state, by judging the slip ratio of the target wheel, if the slip ratio of the target wheel is too large or too small, timing is performed when the pressure of the brake master cylinder is large, and when the timing time does not reach the first preset time, the pressure of the brake wheel cylinder of the target wheel is controlled according to the smaller braking force difference threshold, and after the timing time reaches the first preset time, the pressure of the brake wheel cylinder of the target wheel is controlled according to the larger braking force difference threshold, thereby, by controlling the pressure of the brake wheel cylinder of the target wheel when the slip ratio of the target wheel is too large or too small, the slip ratio of the wheel can be kept within a certain range, so that the braking performance and the anti-lock effect of the vehicle can be ensured, by controlling the braking pressure of the target wheel cylinder with the smaller braking force difference threshold within the first preset time, the limiting effect on the yaw moment can be improved, a certain reaction time can be given to a driver when the road surface sudden change condition occurs, and therefore the lateral stability of the vehicle during braking can be further improved.
To achieve the above object, a second aspect of the present invention proposes a non-transitory computer-readable storage medium having a computer program stored thereon, the computer program, when executed by a processor, implementing the braking control method for a vehicle proposed by the first aspect of the present invention.
According to the non-transitory computer-readable storage medium of the embodiment of the present invention, by executing the stored computer program thereof, the braking performance and the anti-lock effect of the vehicle can be ensured, and the lateral stability of the vehicle when braking can be further improved.
In order to achieve the above object, a third aspect of the present invention provides a brake control apparatus for a vehicle, the apparatus including: the first judgment module is used for judging the slip rate of a target wheel when the vehicle enters a braking state; the obtaining module is used for obtaining the pressure of a brake master cylinder of the vehicle when the first judging module judges that the slip ratio of the target wheel is larger than a first slip ratio threshold value or smaller than a second slip ratio threshold value, wherein the second slip ratio threshold value is smaller than the first slip ratio threshold value; the second judgment module is used for judging whether the pressure of the brake master cylinder is greater than a first pressure threshold value in real time; the timing module is used for timing the time that the pressure of the brake master cylinder is continuously greater than the first pressure threshold when the second judging module judges that the pressure of the brake master cylinder is greater than the first pressure threshold; the control module is used for controlling the pressure of a brake wheel cylinder of the target wheel according to a first braking force difference threshold value when the timing time does not reach a first preset time, and controlling the pressure of the brake wheel cylinder of the target wheel according to a second braking force difference threshold value after the timing time reaches the first preset time, wherein the first braking force difference threshold value is smaller than the second braking force difference threshold value.
According to the brake control device of the vehicle of the embodiment of the invention, when the vehicle enters a braking state, the slip ratio of the target wheel is judged through the first judging module, if the slip ratio of the target wheel is too large or too small, the timing module times when the second judging module judges that the pressure of the brake master cylinder is large, when the timing time does not reach the first preset time, the control module controls the pressure of the brake wheel cylinder of the target wheel according to a smaller brake force difference threshold value, and controls the pressure of the brake wheel cylinder of the target wheel according to a larger brake force difference threshold value after the timing time reaches the first preset time, therefore, the slip ratio of the wheel can be kept in a certain range by controlling the pressure of the brake wheel cylinder of the target wheel when the slip ratio of the target wheel is too large or too small, thereby ensuring the braking performance and the anti-lock effect of the vehicle, the brake wheel cylinder pressure of the target wheel is controlled by a smaller braking force difference threshold value within the first preset time, so that the limiting effect on the yaw moment can be improved, a certain reaction time can be given to a driver when the road surface sudden change condition occurs, and the lateral stability of the vehicle during braking can be further improved.
In order to achieve the above object, a fourth aspect of the present invention proposes a vehicle including the brake control apparatus for a vehicle proposed in the third aspect of the present invention.
According to the vehicle disclosed by the embodiment of the invention, the braking performance and the anti-lock effect are better, and the lateral stability during braking is higher.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
FIG. 1 is a schematic structural diagram of a vehicle according to one embodiment of the present invention;
fig. 2 is a flowchart of a brake control method of a vehicle according to an embodiment of the invention;
FIG. 3 is a flow chart of a method of controlling braking of a vehicle according to an embodiment of the present invention;
FIG. 4 is a block schematic diagram of a brake control apparatus of a vehicle according to an embodiment of the present invention;
FIG. 5 is a block schematic diagram of a vehicle according to an embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
A vehicle and a brake control method and apparatus thereof according to an embodiment of the present invention will be described below with reference to the accompanying drawings.
The vehicle according to the embodiment of the present invention is an ABS (Antilock Brake System) hydraulic Brake vehicle, and includes a master cylinder and wheel cylinders provided corresponding to each wheel. As shown in fig. 1, valve bodies 2fl, 2fr, 2rl and 2rr of wheel brake cylinders are respectively and correspondingly arranged at a left front wheel 1fl, a right front wheel 1fr, a left rear wheel 1rl and a right rear wheel 1rr of the vehicle, each valve body is further connected with a valve body controller 3fl, 3fr, 3rl and 3rr, respectively, and each valve body controller is connected with an ECU (Electronic Control Unit) of the vehicle. When the ECU issues a brake control command, the valve body controller may control the corresponding valve body to adjust the pressure of each brake wheel cylinder, thereby applying a braking force to each wheel, respectively. The braking control method of the vehicle described below may be executed by the ECU as a main body.
Fig. 2 is a flowchart of a brake control method of a vehicle according to an embodiment of the present invention.
As shown in fig. 2, a braking control method of a vehicle according to an embodiment of the present invention includes the steps of:
and S1, when the vehicle enters the braking state, the slip ratio of the target wheel is judged.
In one embodiment of the present invention, the braking control may be performed for each wheel of the vehicle, i.e., each wheel of the vehicle is a target wheel. Alternatively, the control may be performed alternatively for two coaxial wheels of the vehicle, i.e., with any one of each of the two coaxial wheels as the target wheel. Wherein the control effect of the braking control for each wheel is optimized.
In one embodiment of the present invention, as shown in fig. 1, the vehicle may further include wheel speed sensors 4fl, 4fr, 4rl, and 4rr provided corresponding to each wheel to detect wheel speeds of the left front wheel 1fl, the right front wheel 1fr, the left rear wheel 1rl, and the right rear wheel 1rr, respectively. After the ECU determines that the vehicle enters the braking state, the wheel speed detected by each wheel speed sensor may be acquired, and the slip rate of the target wheel may be acquired according to the wheel speed of the target wheel.
S2, when the slip ratio of the target wheel is larger than the first slip ratio threshold value or smaller than the second slip ratio threshold value, obtaining the pressure of the brake master cylinder of the vehicle, and judging whether the pressure of the brake master cylinder is larger than the first pressure threshold value or not in real time, wherein the second slip ratio threshold value is smaller than the first slip ratio threshold value.
The first slip rate threshold and the second slip rate threshold may be preset to be used as upper and lower threshold values for slip rate control, respectively, and when the slip rate of the target wheel is greater than the first slip rate threshold or smaller than the second slip rate threshold, that is, the slip rate of the target wheel is too high or too low, the subsequent control process is executed so as to control the slip rate of the target wheel within the upper and lower threshold values.
In one embodiment of the present invention, the vehicle may include a master cylinder pressure sensor provided corresponding to the master cylinder to detect a hydraulic pressure in the master cylinder, i.e., a master cylinder pressure.
S3, if the master cylinder pressure is larger than the first pressure threshold value, timing the time that the master cylinder pressure is continuously larger than the first pressure threshold value.
The pressure of the brake master cylinder is acquired and judged in real time, timing accumulation is carried out when the pressure of the brake master cylinder is continuously greater than a first pressure threshold value, and timing zero clearing is carried out when the pressure of the brake master cylinder is smaller than or equal to the first pressure threshold value.
And S4, when the timing time does not reach the first preset time, controlling the brake wheel cylinder pressure of the target wheel according to the first braking force difference threshold value.
And S5, controlling the brake wheel cylinder pressure of the target wheel according to a second braking force difference threshold value after the timing time reaches a first preset time, wherein the first braking force difference threshold value is smaller than the second braking force difference threshold value.
And when the slip ratio of the target wheel is smaller than the second slip ratio threshold value, the brake wheel cylinder pressure of the target wheel can be directly controlled according to the first braking force difference threshold value.
In one embodiment of the present invention, when the slip ratio of the target wheel is smaller than the second slip ratio threshold value, controlling the brake cylinder pressure of the target wheel according to the first braking force difference threshold value includes: obtaining the current brake cylinder pressure of a target wheel and the brake cylinder pressure of a coaxial wheel of the target wheel; calculating an absolute value of a difference value between a brake cylinder pressure of the target wheel and a brake cylinder pressure of a coaxial wheel of the target wheel to obtain a braking force difference; judging whether the braking force difference is larger than a first braking force difference threshold value or not; if the braking force difference is less than or equal to the first braking force difference threshold value, increasing the brake wheel cylinder pressure of the target wheel; if the braking force difference is larger than the first braking force difference threshold value, further judging whether the brake cylinder pressure of the target wheel is larger than the brake cylinder pressure of the coaxial wheel of the target wheel; if the brake cylinder pressure of the target wheel is larger than the brake cylinder pressure of the coaxial wheel of the target wheel, maintaining the brake cylinder pressure of the target wheel; and if the brake cylinder pressure of the target wheel is less than or equal to the brake cylinder pressure of the coaxial wheel of the target wheel, increasing the brake cylinder pressure of the target wheel.
In one embodiment of the present invention, when the slip ratio of the target wheel is smaller than the second slip ratio threshold value, controlling the brake cylinder pressure of the target wheel according to the second braking force difference threshold value includes: obtaining the current brake cylinder pressure of a target wheel and the brake cylinder pressure of a coaxial wheel of the target wheel; calculating an absolute value of a difference value between a brake cylinder pressure of the target wheel and a brake cylinder pressure of a coaxial wheel of the target wheel to obtain a braking force difference; judging whether the braking force difference is larger than a second braking force difference threshold value or not; if the braking force difference is less than or equal to the second braking force difference threshold value, increasing the brake wheel cylinder pressure of the target wheel; if the braking force difference is larger than the second braking force difference threshold value, further judging whether the brake cylinder pressure of the target wheel is larger than the brake cylinder pressure of the coaxial wheel of the target wheel; if the brake cylinder pressure of the target wheel is larger than the brake cylinder pressure of the coaxial wheel of the target wheel, maintaining the brake cylinder pressure of the target wheel; and if the brake cylinder pressure of the target wheel is less than or equal to the brake cylinder pressure of the coaxial wheel of the target wheel, increasing the brake cylinder pressure of the target wheel.
In one embodiment of the present invention, when the slip ratio of the target wheel is greater than the first slip ratio threshold value, controlling the brake cylinder pressure of the target wheel according to the first braking force difference threshold value includes: obtaining the current brake cylinder pressure of a target wheel and the brake cylinder pressure of a coaxial wheel of the target wheel; calculating an absolute value of a difference value between a brake cylinder pressure of the target wheel and a brake cylinder pressure of a coaxial wheel of the target wheel to obtain a braking force difference; judging whether the braking force difference is larger than a first braking force difference threshold value or not; if the braking force difference is smaller than or equal to the first braking force difference threshold value, reducing the brake wheel cylinder pressure of the target wheel; if the braking force difference is larger than the first braking force difference threshold value, further judging whether the brake cylinder pressure of the target wheel is smaller than the brake cylinder pressure of the coaxial wheel of the target wheel; if the brake cylinder pressure of the target wheel is less than the brake cylinder pressure of the coaxial wheel of the target wheel, reducing the brake cylinder pressure of the target wheel and reducing the brake cylinder pressure of the coaxial wheel of the target wheel; and if the brake cylinder pressure of the target wheel is larger than or equal to the brake cylinder pressure of the coaxial wheel of the target wheel, reducing the brake cylinder pressure of the target wheel.
In one embodiment of the present invention, controlling the brake cylinder pressure of the target wheel according to the second braking force difference threshold value when the slip ratio of the target wheel is greater than the first slip ratio threshold value includes: obtaining the current brake cylinder pressure of a target wheel and the brake cylinder pressure of a coaxial wheel of the target wheel; calculating an absolute value of a difference value between a brake cylinder pressure of the target wheel and a brake cylinder pressure of a coaxial wheel of the target wheel to obtain a braking force difference; judging whether the braking force difference is larger than a second braking force difference threshold value or not; if the braking force difference is smaller than or equal to the second braking force difference threshold value, reducing the brake wheel cylinder pressure of the target wheel; if the braking force difference is larger than the second braking force difference threshold value, further judging whether the brake cylinder pressure of the target wheel is smaller than the brake cylinder pressure of the coaxial wheel of the target wheel; if the brake cylinder pressure of the target wheel is less than the brake cylinder pressure of the coaxial wheel of the target wheel, reducing the brake cylinder pressure of the target wheel and reducing the brake cylinder pressure of the coaxial wheel of the target wheel; and if the brake cylinder pressure of the target wheel is larger than or equal to the brake cylinder pressure of the coaxial wheel of the target wheel, reducing the brake cylinder pressure of the target wheel.
As shown in fig. 1, the vehicle may further include wheel cylinder pressure sensors 5fl, 5fr, 5rl, and 5rr provided corresponding to each brake wheel cylinder to detect hydraulic pressures in the brake wheel cylinders of the front left wheel 1fl, the front right wheel 1fr, the rear left wheel 1rl, and the rear right wheel 1rr, i.e., wheel cylinder pressures, respectively. It should be noted that, there is a corresponding relationship between the brake wheel cylinder pressure and the braking force of the wheel, and the specific relationship expression of the two is also influenced by some parameters of the hydraulic brake system, so that it is not convenient to convert the specific braking force in the embodiment of the present invention, and the braking force of the wheel is directly represented by the brake wheel cylinder pressure.
That is, if the pressure of the brake master cylinder is larger, when the timing time does not reach the first preset time, whether the pressure difference of the brake wheel cylinders between the two coaxial wheels is too large can be judged according to the first braking force difference threshold value; and when the timing time reaches the first preset time, judging whether the pressure difference of the brake wheel cylinders between the two coaxial wheels is too large according to the second braking force difference threshold value.
If the pressure of the brake master cylinder is smaller, the pressure difference of the brake wheel cylinders between the two coaxial wheels is smaller, and generally cannot reach the second braking force difference threshold value, so that whether the pressure difference of the brake wheel cylinders between the two coaxial wheels is too large can be directly judged according to the first braking force difference threshold value when the pressure of the brake master cylinder is smaller.
Further, if the slip ratio of the target wheel is too small and the braking performance is insufficient, when the pressure difference between the brake cylinders of the two coaxial wheels is too large and the pressure of the brake cylinder of the target wheel is greater than that of the coaxial wheel, the pressure of the brake cylinder of the target wheel is maintained to inhibit the pressure of the brake cylinder of the target wheel from continuously increasing, so as to prevent the braking force difference between the two coaxial wheels from increasing; when the pressure difference of the brake wheel cylinders between the two coaxial wheels is too small, the pressure of the brake wheel cylinders of the target wheel is increased to properly increase the slip ratio of the target wheel; and when the pressure difference of the brake wheel cylinders between the two coaxial wheels is overlarge and the pressure of the brake wheel cylinder of the target wheel is smaller than that of the coaxial wheel, reducing the braking force difference of the two coaxial wheels by increasing the pressure of the brake wheel cylinder of the target wheel, and properly increasing the slip ratio of the target wheel.
If the slip rate of the target wheel is too large and tends to be locked, reducing the braking force difference of the two coaxial wheels by reducing the pressure of the brake wheel cylinder of the target wheel when the pressure difference of the brake wheel cylinder between the two coaxial wheels is too large and the pressure of the brake wheel cylinder of the target wheel is greater than that of the brake wheel cylinder of the coaxial wheel; when the pressure difference of the brake wheel cylinders between the two coaxial wheels is too small, the pressure of the brake wheel cylinders of the target wheel is reduced to properly reduce the slip rate of the target wheel; and when the pressure difference between the brake cylinder pressure of the two coaxial wheels is too large and the pressure of the brake cylinder of the target wheel is smaller than that of the coaxial wheel, reducing the pressure of the brake cylinder of the target wheel to properly reduce the slip ratio of the target wheel, and correspondingly reducing the pressure of the brake cylinder of the coaxial wheel to prevent the pressure difference between the brake cylinders of the two coaxial wheels from increasing. Preferably, the braking force difference between the two coaxial wheels can also be reduced by reducing the wheel cylinder pressure of the target wheel by different magnitudes, i.e., by reducing the wheel cylinder pressure of the target wheel by a smaller magnitude and by reducing the wheel cylinder pressure of the coaxial wheel by a larger magnitude.
In addition, in one embodiment of the invention, it may also be determined whether the brake cylinder pressure of the target wheel is currently maintained before the determination of the slip ratio of the target wheel. If the brake wheel cylinder pressure of the target wheel is not maintained at present, further judging whether the slip rate of the target wheel is greater than a third slip rate threshold value; maintaining the brake cylinder pressure of the target wheel if the slip ratio of the target wheel is greater than a third slip ratio threshold, wherein the third slip ratio threshold is greater than the second slip ratio threshold and less than the first slip ratio threshold.
And when the brake cylinder pressure of the target wheel is currently maintained and the slip ratio of the target wheel is greater than the second slip ratio threshold value and less than the first slip ratio threshold value, the brake cylinder pressure of the target wheel may be continuously maintained.
That is, in the process of not maintaining the brake cylinder pressure of the target wheel, if the slip ratio of the target wheel reaches a preferable state of being greater than the third slip ratio threshold value, the brake cylinder pressure of the target wheel may be maintained; in maintaining the brake cylinder pressure of the target wheel, if the slip ratio of the target wheel is between the second slip ratio threshold value and the first slip ratio threshold value, but is neither too large nor too small, the brake cylinder pressure of the target wheel is continuously maintained.
Therefore, the braking force difference between the two coaxial wheels can be reduced as much as possible, the yaw moment between the left wheel and the right wheel of the vehicle is limited, the slip rate can be adjusted to be within the optimal slip rate, and the braking control effect is improved.
The brake control method of the vehicle is suitable for various working conditions, and particularly can more remarkably exert the advantages under the working conditions that the adhesion coefficients of the left wheel and the right wheel of the vehicle are different.
The following further describes a braking control method of a vehicle according to the present invention with reference to a specific embodiment.
In an embodiment of the present invention, taking the target wheel as any one of the rear wheels as an example, as shown in fig. 3, the braking control method of the vehicle includes the steps of:
s101, judging whether the vehicle is braked. If yes, executing step S102; if not, the ECU ends the current control cycle and executes the next control cycle.
And S102, judging whether the brake wheel cylinder pressure of the target rear wheel is maintained at present. If not, executing step S103; if so, step S105 is performed.
And S103, judging whether the slip ratio S of the target rear wheel is greater than A. If yes, executing step S104; if not, the ECU ends the current control cycle and executes the next control cycle.
And S104, maintaining the brake wheel cylinder pressure of the target rear wheel. The next control cycle is entered after this step.
And S105, judging whether the slip ratio S of the target rear wheel is greater than B. If yes, go to step S116; if not, step S106 is performed.
And S106, judging whether the slip ratio S of the target rear wheel is smaller than C. Where B > a > C, A, B, C correspond to the third, first and second slip ratio thresholds of the above embodiments, respectively. It should be understood that the slip ratio of the wheel is preferably in a range of, for example, 10% to 30% in terms of the anti-lock control. Accordingly, the specific value of A, B, C may be set according to the range. B, C are upper and lower threshold values corresponding to better control effect, when the slip ratio of the wheel is greater than B, the wheel area is locked, when the slip ratio of the wheel is less than C, the braking performance of the wheel is insufficient. If yes, go to step S107; if not, step S104 is executed.
S107, it is determined whether or not the brake master cylinder pressure CHP is greater than E. If yes, go to step S108; if not, step S109 is performed.
And S108, timing.
And S109, timing and clearing. After this step, step S111 is performed.
S110, judging whether the timing time T reaches T. And T is the optimal time calibrated according to the requirement of judging the threshold value of whether the pressure difference of the brake wheel cylinder between the two coaxial wheels is overlarge. If yes, go to step S112; if not, step S111 is performed.
And S111, judging whether the brake wheel cylinder pressure difference △ P of the two rear wheels is larger than K, if so, executing the step S113, and if not, executing the step S114.
S112, judging whether the brake wheel cylinder pressure difference △ P of the two rear wheels is more than D.K < D, wherein K is a braking force difference threshold value calibrated according to the requirement of a judgment threshold value for judging whether the brake wheel cylinder pressure difference between the two coaxial wheels is too large, namely a first braking force difference threshold value of the embodiment, and D is a second braking force difference threshold value of the embodiment.
And S113, judging whether the target rear wheel is an outer wheel. When the pressure of the brake wheel cylinder of the target rear wheel is greater than that of the brake wheel cylinder of the other rear wheel and the difference between the two is greater than a preset value, the target rear wheel can be judged to be the outer wheel. If yes, go to step S115; if not, step S114 is performed.
And S114, increasing the brake wheel cylinder pressure of the target rear wheel.
And S115, maintaining the brake wheel cylinder pressure of the target rear wheel. Since the slip ratio of the target rear wheel is less than C and the braking performance is insufficient, it is not preferable to reduce the wheel cylinder pressure of the target rear wheel, and the wheel cylinder pressure of the target rear wheel can be increased or maintained only according to the actual determination result.
S116, it is determined whether the brake master cylinder pressure CHP is greater than E. If so, go to step S117; if not, step S118 is performed.
And S117, timing.
And S118, timing is cleared. After which step S121 is performed.
And S119, judging whether the timing time T reaches T. If yes, go to step S120; if not, step S121 is performed.
And S120, judging whether the brake wheel cylinder pressure difference △ P of the two rear wheels is larger than D, if so, executing the step S122, and if not, executing the step S123.
S121, judging whether the brake wheel cylinder pressure difference △ P of the two rear wheels is larger than K, if so, executing step S122, and if not, executing step S123.
And S122, judging whether the target rear wheel is an inner wheel. When the pressure of the brake wheel cylinder of the target rear wheel is smaller than that of the brake wheel cylinder of the other rear wheel and the difference between the two is larger than a preset value, the target rear wheel can be judged to be the inner wheel. If yes, go to step S124; if not, step S123 is performed.
And S123, reducing the brake wheel cylinder pressure of the target rear wheel.
And S124, reducing the brake wheel cylinder pressure of the two rear wheels. Since the slip ratio of the target rear wheel is greater than B, the target rear wheel tends to be in a locked state, and therefore, the brake cylinder pressure of the target rear wheel is not suitable to be increased, and the brake cylinder pressure of the target rear wheel can only be decreased according to the actual judgment result. When the target rear wheel is an inner wheel, that is, the brake cylinder pressure is lower than that of the other rear wheel, in order to prevent the brake cylinder pressure difference of the two rear wheels from further increasing, the brake cylinder pressure of the other rear wheel should be reduced accordingly, preferably, the reduction range of the brake cylinder pressure of the other rear wheel is larger than that of the target rear wheel, so that the brake cylinder pressure difference of the two rear wheels can be reduced.
After steps S114, S115, S123, and S124, the next control cycle may be entered.
In summary, according to the brake control method of a vehicle according to an embodiment of the present invention, when the vehicle enters a braking state, by determining the slip ratio of the target wheel, if the slip ratio of the target wheel is too large or too small, timing is performed when the master cylinder pressure is large, and when the timing time does not reach a first preset time, the brake cylinder pressure of the target wheel is controlled according to a smaller braking force difference threshold, and after the timing time reaches the first preset time, the brake cylinder pressure of the target wheel is controlled according to a larger braking force difference threshold, whereby by controlling the brake cylinder pressure of the target wheel when the slip ratio of the target wheel is too large or too small, the slip ratio of the wheel can be maintained within a certain range, and thus the braking performance and the anti-lock effect of the vehicle can be ensured, by controlling the brake cylinder pressure of the target wheel with a smaller braking force difference threshold within the first preset time, the limiting effect on the yaw moment can be improved, a certain reaction time can be given to a driver when the road surface sudden change condition occurs, and therefore the lateral stability of the vehicle during braking can be further improved.
The invention also provides a non-transitory computer readable storage medium corresponding to the above embodiment.
A non-transitory computer-readable storage medium of an embodiment of the present invention has stored thereon a computer program that, when executed by a processor, can implement the braking control method of a vehicle proposed by the above-described embodiment of the present invention.
According to the non-transitory computer-readable storage medium of the embodiment of the present invention, by executing the stored computer program thereof, the braking performance and the anti-lock effect of the vehicle can be ensured, and the lateral stability of the vehicle when braking can be further improved.
The invention further provides a vehicle brake control device corresponding to the embodiment.
As shown in fig. 4, the brake control apparatus for a vehicle according to the embodiment of the present invention includes a first determining module 10, an obtaining module 20, a second determining module 30, a timing module 40, and a control module 50.
The first judging module 10 is configured to judge a slip ratio of a target wheel when a vehicle enters a braking state; the obtaining module 20 is configured to obtain a brake master cylinder pressure of the vehicle when the first determining module 10 determines that the slip ratio of the target wheel is greater than a first slip ratio threshold or smaller than a second slip ratio threshold, where the second slip ratio threshold is smaller than the first slip ratio threshold; the second judging module 30 is used for judging whether the pressure of the brake master cylinder is greater than the first pressure threshold value in real time; the timing module 40 is configured to time the time that the master cylinder pressure is continuously greater than the first pressure threshold when the second determining module 30 determines that the master cylinder pressure is greater than the first pressure threshold; the control module 50 is configured to control the brake cylinder pressure of the target wheel according to a first braking force difference threshold when the timing time does not reach a first preset time, and control the brake cylinder pressure of the target wheel according to a second braking force difference threshold after the timing time reaches the first preset time, where the first braking force difference threshold is smaller than the second braking force difference threshold.
The control module 50 may directly control the wheel cylinder pressure of the target wheel according to the first braking force difference threshold value when the second determination module 30 determines that the master cylinder pressure is less than or equal to the first pressure threshold value.
In one embodiment of the present invention, the braking control may be performed for each wheel of the vehicle, i.e., each wheel of the vehicle is a target wheel. Alternatively, the control may be performed alternatively for two coaxial wheels of the vehicle, i.e., with any one of each of the two coaxial wheels as the target wheel. Wherein the control effect of the braking control for each wheel is optimized.
In one embodiment of the present invention, as shown in fig. 1, the vehicle may further include wheel speed sensors 4fl, 4fr, 4rl, and 4rr provided corresponding to each wheel to detect wheel speeds of the left front wheel 1fl, the right front wheel 1fr, the left rear wheel 1rl, and the right rear wheel 1rr, respectively. After determining that the vehicle enters the braking state, the first determining module 10 may obtain a wheel speed detected by each wheel speed sensor, and obtain a slip rate of the target wheel according to the wheel speed of the target wheel.
In one embodiment of the present invention, a first slip ratio threshold value and a second slip ratio threshold value may be preset as upper and lower threshold values for slip ratio control, respectively, and when the slip ratio of the target wheel is greater than the first slip ratio threshold value or less than the second slip ratio threshold value, i.e., the slip ratio of the target wheel is too high or too low, the slip ratio of the target wheel is controlled within the upper and lower threshold values by the control of the brake control device.
In one embodiment of the present invention, the vehicle may include a master cylinder pressure sensor disposed corresponding to the master cylinder, and the obtaining module 20 obtains the hydraulic pressure in the master cylinder, i.e., the master cylinder pressure, through the master cylinder pressure sensor.
The obtaining module 20 obtains the pressure of the brake master cylinder and the second judging module 30 judges the pressure of the brake master cylinder in real time, when the pressure of the brake master cylinder is continuously greater than the first pressure threshold, the timing module 40 counts time and accumulates like a timer, and when the pressure of the brake master cylinder is less than or equal to the first pressure threshold, the timing module 40 counts time and clears zero.
In an embodiment of the present invention, when the first determination module 10 determines that the slip ratio of the target wheel is less than the second slip ratio threshold, the control module 50 may specifically be configured to: obtaining the current brake cylinder pressure of a target wheel and the brake cylinder pressure of a coaxial wheel of the target wheel; calculating an absolute value of a difference value between a brake cylinder pressure of the target wheel and a brake cylinder pressure of a coaxial wheel of the target wheel to obtain a braking force difference; judging whether the braking force difference is larger than a first braking force difference threshold value or not; if the braking force difference is less than or equal to the first braking force difference threshold value, increasing the brake wheel cylinder pressure of the target wheel; if the braking force difference is larger than the first braking force difference threshold value, further judging whether the brake cylinder pressure of the target wheel is larger than the brake cylinder pressure of the coaxial wheel of the target wheel; if the brake cylinder pressure of the target wheel is larger than the brake cylinder pressure of the coaxial wheel of the target wheel, maintaining the brake cylinder pressure of the target wheel; and if the brake cylinder pressure of the target wheel is less than or equal to the brake cylinder pressure of the coaxial wheel of the target wheel, increasing the brake cylinder pressure of the target wheel.
In an embodiment of the present invention, when the first determining module 10 determines that the slip ratio of the target wheel is smaller than the second slip ratio threshold, the control module 50 is further specifically configured to: obtaining the current brake cylinder pressure of a target wheel and the brake cylinder pressure of a coaxial wheel of the target wheel; calculating an absolute value of a difference value between a brake cylinder pressure of the target wheel and a brake cylinder pressure of a coaxial wheel of the target wheel to obtain a braking force difference; judging whether the braking force difference is larger than a second braking force difference threshold value or not; if the braking force difference is less than or equal to the second braking force difference threshold value, increasing the brake wheel cylinder pressure of the target wheel; if the braking force difference is larger than the second braking force difference threshold value, further judging whether the brake cylinder pressure of the target wheel is larger than the brake cylinder pressure of the coaxial wheel of the target wheel; if the brake cylinder pressure of the target wheel is larger than the brake cylinder pressure of the coaxial wheel of the target wheel, maintaining the brake cylinder pressure of the target wheel; and if the brake cylinder pressure of the target wheel is less than or equal to the brake cylinder pressure of the coaxial wheel of the target wheel, increasing the brake cylinder pressure of the target wheel.
In an embodiment of the present invention, when the first determination module 10 determines that the slip ratio of the target wheel is greater than the first slip ratio threshold, the control module 50 may specifically be configured to: obtaining the current brake cylinder pressure of a target wheel and the brake cylinder pressure of a coaxial wheel of the target wheel; calculating an absolute value of a difference value between a brake cylinder pressure of the target wheel and a brake cylinder pressure of a coaxial wheel of the target wheel to obtain a braking force difference; judging whether the braking force difference is larger than a first braking force difference threshold value or not; if the braking force difference is smaller than or equal to the first braking force difference threshold value, reducing the brake wheel cylinder pressure of the target wheel; if the braking force difference is larger than the first braking force difference threshold value, further judging whether the brake cylinder pressure of the target wheel is smaller than the brake cylinder pressure of the coaxial wheel of the target wheel; if the brake cylinder pressure of the target wheel is less than the brake cylinder pressure of the coaxial wheel of the target wheel, reducing the brake cylinder pressure of the target wheel and reducing the brake cylinder pressure of the coaxial wheel of the target wheel; and if the brake cylinder pressure of the target wheel is larger than or equal to the brake cylinder pressure of the coaxial wheel of the target wheel, reducing the brake cylinder pressure of the target wheel.
In an embodiment of the present invention, when the first determining module 10 determines that the slip ratio of the target wheel is greater than the first slip ratio threshold, the control module 50 is further specifically configured to: obtaining the current brake cylinder pressure of a target wheel and the brake cylinder pressure of a coaxial wheel of the target wheel; calculating an absolute value of a difference value between a brake cylinder pressure of the target wheel and a brake cylinder pressure of a coaxial wheel of the target wheel to obtain a braking force difference; judging whether the braking force difference is larger than a second braking force difference threshold value or not; if the braking force difference is smaller than or equal to the second braking force difference threshold value, reducing the brake wheel cylinder pressure of the target wheel; if the braking force difference is larger than the second braking force difference threshold value, further judging whether the brake cylinder pressure of the target wheel is smaller than the brake cylinder pressure of the coaxial wheel of the target wheel; if the brake cylinder pressure of the target wheel is less than the brake cylinder pressure of the coaxial wheel of the target wheel, reducing the brake cylinder pressure of the target wheel and reducing the brake cylinder pressure of the coaxial wheel of the target wheel; and if the brake cylinder pressure of the target wheel is larger than or equal to the brake cylinder pressure of the coaxial wheel of the target wheel, reducing the brake cylinder pressure of the target wheel.
As shown in fig. 1, the vehicle may further include wheel cylinder pressure sensors 5fl, 5fr, 5rl and 5rr corresponding to each brake wheel cylinder, and the control module 50 may obtain hydraulic pressures in the brake wheel cylinders of the front left wheel 1fl, the front right wheel 1fr, the rear left wheel 1rl and the rear right wheel 1rr, that is, the brake wheel cylinder pressures, through the wheel cylinder pressure sensors 5fl, 5fr, 5rl and 5 rr. It should be noted that, there is a corresponding relationship between the brake wheel cylinder pressure and the braking force of the wheel, and the specific relationship expression of the two is also influenced by some parameters of the hydraulic brake system, so that it is not convenient to convert the specific braking force in the embodiment of the present invention, and the braking force of the wheel is directly represented by the brake wheel cylinder pressure.
That is, if the pressure of the brake master cylinder is larger, when the timing time does not reach the first preset time, whether the pressure difference of the brake wheel cylinders between the two coaxial wheels is too large can be judged according to the first braking force difference threshold value; and when the timing time reaches the first preset time, judging whether the pressure difference of the brake wheel cylinders between the two coaxial wheels is too large according to the second braking force difference threshold value.
If the pressure of the brake master cylinder is smaller, the pressure difference of the brake wheel cylinders between the two coaxial wheels is smaller, and generally cannot reach the second braking force difference threshold value, so that whether the pressure difference of the brake wheel cylinders between the two coaxial wheels is too large can be directly judged according to the first braking force difference threshold value when the pressure of the brake master cylinder is smaller.
Further, if the slip ratio of the target wheel is too small and the braking performance is insufficient, when the pressure difference between the brake cylinders of the two coaxial wheels is too large and the pressure of the brake cylinder of the target wheel is greater than that of the coaxial wheel, the pressure of the brake cylinder of the target wheel is maintained to inhibit the pressure of the brake cylinder of the target wheel from continuously increasing, so as to prevent the braking force difference between the two coaxial wheels from increasing; when the pressure difference of the brake wheel cylinders between the two coaxial wheels is too small, the pressure of the brake wheel cylinders of the target wheel is increased to properly increase the slip ratio of the target wheel; and when the pressure difference of the brake wheel cylinders between the two coaxial wheels is overlarge and the pressure of the brake wheel cylinder of the target wheel is smaller than that of the coaxial wheel, reducing the braking force difference of the two coaxial wheels by increasing the pressure of the brake wheel cylinder of the target wheel, and properly increasing the slip ratio of the target wheel.
If the slip rate of the target wheel is too large and tends to be locked, reducing the braking force difference of the two coaxial wheels by reducing the pressure of the brake wheel cylinder of the target wheel when the pressure difference of the brake wheel cylinder between the two coaxial wheels is too large and the pressure of the brake wheel cylinder of the target wheel is greater than that of the brake wheel cylinder of the coaxial wheel; when the pressure difference of the brake wheel cylinders between the two coaxial wheels is too small, the pressure of the brake wheel cylinders of the target wheel is reduced to properly reduce the slip rate of the target wheel; and when the pressure difference between the brake cylinder pressure of the two coaxial wheels is too large and the pressure of the brake cylinder of the target wheel is smaller than that of the coaxial wheel, reducing the pressure of the brake cylinder of the target wheel to properly reduce the slip ratio of the target wheel, and correspondingly reducing the pressure of the brake cylinder of the coaxial wheel to prevent the pressure difference between the brake cylinders of the two coaxial wheels from increasing. Preferably, the braking force difference between the two coaxial wheels can also be reduced by reducing the wheel cylinder pressure of the target wheel by different magnitudes, i.e., by reducing the wheel cylinder pressure of the target wheel by a smaller magnitude and by reducing the wheel cylinder pressure of the coaxial wheel by a larger magnitude.
In addition, in one embodiment of the present invention, the brake control apparatus of the vehicle may further include a third determination module for determining whether the control module 50 currently maintains the brake cylinder pressure of the target wheel before the first determination module 10 determines the slip ratio of the target wheel. Wherein, if the third determination module determines that the brake cylinder pressure of the target wheel is not currently maintained, the first determination module 10 further determines whether the slip ratio of the target wheel is greater than a third slip ratio threshold. The control module 50 maintains the brake cylinder pressure of the target wheel when the first determination module 10 determines that the slip ratio of the target wheel is greater than a third slip ratio threshold, wherein the third slip ratio threshold is greater than the second slip ratio threshold and less than the first slip ratio threshold.
While the control module 50 currently maintains the brake cylinder pressure of the target wheel, and the first determination module 10 determines that the slip rate of the target wheel is greater than the second slip rate threshold and less than the first slip rate threshold, the control module 50 may continue to maintain the brake cylinder pressure of the target wheel.
That is, in the process of not maintaining the brake cylinder pressure of the target wheel, if the slip ratio of the target wheel reaches a preferable state of being greater than the third slip ratio threshold value, the brake cylinder pressure of the target wheel may be maintained; in maintaining the brake cylinder pressure of the target wheel, if the slip ratio of the target wheel is between the second slip ratio threshold value and the first slip ratio threshold value, but is neither too large nor too small, the brake cylinder pressure of the target wheel is continuously maintained.
Therefore, the braking force difference between the two coaxial wheels can be reduced as much as possible, the yaw moment between the left wheel and the right wheel of the vehicle is limited, the slip rate can be adjusted to be within the optimal slip rate, and the braking control effect is improved.
The brake control method of the vehicle is suitable for various working conditions, and particularly can more remarkably exert the advantages under the working conditions that the adhesion coefficients of the left wheel and the right wheel of the vehicle are different.
According to the brake control device of the vehicle of the embodiment of the invention, when the vehicle enters a braking state, the slip ratio of the target wheel is judged through the first judging module, if the slip ratio of the target wheel is too large or too small, the timing module times when the second judging module judges that the pressure of the brake master cylinder is large, when the timing time does not reach the first preset time, the control module controls the pressure of the brake wheel cylinder of the target wheel according to a smaller brake force difference threshold value, and controls the pressure of the brake wheel cylinder of the target wheel according to a larger brake force difference threshold value after the timing time reaches the first preset time, therefore, the slip ratio of the wheel can be kept in a certain range by controlling the pressure of the brake wheel cylinder of the target wheel when the slip ratio of the target wheel is too large or too small, thereby ensuring the braking performance and the anti-lock effect of the vehicle, the brake wheel cylinder pressure of the target wheel is controlled by a smaller braking force difference threshold value within the first preset time, so that the limiting effect on the yaw moment can be improved, a certain reaction time can be given to a driver when the road surface sudden change condition occurs, and the lateral stability of the vehicle during braking can be further improved.
The invention further provides a vehicle corresponding to the embodiment.
As shown in fig. 5, a vehicle 1000 according to an embodiment of the present invention includes the brake control device 100 according to the embodiment of the present invention, and for a specific implementation, reference may be made to the embodiment described above, and details are not repeated herein to avoid redundancy.
According to the vehicle disclosed by the embodiment of the invention, the braking performance and the anti-lock effect are better, and the lateral stability during braking is higher.
In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims (14)

1. A brake control method of a vehicle, characterized by comprising the steps of:
judging the slip rate of a target wheel when the vehicle enters a braking state;
when the slip ratio of the target wheel is larger than a first slip ratio threshold value or smaller than a second slip ratio threshold value, acquiring the pressure of a brake master cylinder of the vehicle, and judging whether the pressure of the brake master cylinder is larger than the first pressure threshold value or not in real time, wherein the second slip ratio threshold value is smaller than the first slip ratio threshold value;
if the brake master cylinder pressure is greater than the first pressure threshold, timing the time that the brake master cylinder pressure is continuously greater than the first pressure threshold;
when the timing time does not reach a first preset time, controlling the brake wheel cylinder pressure of the target wheel according to a first braking force difference threshold value;
and after the timing time reaches the first preset time, controlling the brake wheel cylinder pressure of the target wheel according to a second braking force difference threshold value, wherein the first braking force difference threshold value is smaller than the second braking force difference threshold value.
2. The brake control method for a vehicle according to claim 1, characterized in that when the master cylinder pressure is equal to or less than the first pressure threshold value, the wheel cylinder pressure of the target wheel is controlled directly according to the first braking force difference threshold value.
3. The brake control method of a vehicle according to claim 1, wherein controlling the brake cylinder pressure of the target wheel according to a first braking force difference threshold value/a second braking force difference threshold value when the slip ratio of the target wheel is smaller than the second slip ratio threshold value includes:
obtaining the current brake cylinder pressure of the target wheel and the brake cylinder pressure of the coaxial wheel of the target wheel;
calculating an absolute value of a difference value between the brake cylinder pressure of the target wheel and the brake cylinder pressure of the coaxial wheel of the target wheel to obtain a braking force difference;
judging whether the braking force difference is greater than the first braking force difference threshold value/a second braking force difference threshold value;
increasing a brake wheel cylinder pressure of the target wheel if the braking force difference is less than or equal to the first/second braking force difference threshold values;
if the braking force difference is larger than the first braking force difference threshold value/second braking force difference threshold value, further judging whether the brake cylinder pressure of the target wheel is larger than the brake cylinder pressure of the coaxial wheel of the target wheel;
maintaining the brake cylinder pressure of the target wheel if the brake cylinder pressure of the target wheel is greater than the brake cylinder pressure of the coaxial wheel of the target wheel;
and if the brake cylinder pressure of the target wheel is less than or equal to the brake cylinder pressure of the coaxial wheel of the target wheel, increasing the brake cylinder pressure of the target wheel.
4. The brake control method of a vehicle according to claim 1, wherein controlling the brake cylinder pressure of the target wheel according to a first braking force difference threshold value/a second braking force difference threshold value when the slip ratio of the target wheel is greater than the first slip ratio threshold value includes:
obtaining the current brake cylinder pressure of the target wheel and the brake cylinder pressure of the coaxial wheel of the target wheel;
calculating an absolute value of a difference value between the brake cylinder pressure of the target wheel and the brake cylinder pressure of the coaxial wheel of the target wheel to obtain a braking force difference;
judging whether the braking force difference is greater than the first braking force difference threshold value/a second braking force difference threshold value;
reducing a brake wheel cylinder pressure of the target wheel if the braking force difference is less than or equal to the first/second braking force difference threshold values;
if the braking force difference is greater than the first/second braking force difference threshold, further determining whether a brake cylinder pressure of the target wheel is less than a brake cylinder pressure of a coaxial wheel of the target wheel;
if the brake cylinder pressure of the target wheel is smaller than the brake cylinder pressure of the coaxial wheel of the target wheel, reducing the brake cylinder pressure of the target wheel and reducing the brake cylinder pressure of the coaxial wheel of the target wheel;
and if the brake cylinder pressure of the target wheel is larger than or equal to the brake cylinder pressure of the coaxial wheel of the target wheel, reducing the brake cylinder pressure of the target wheel.
5. The brake control method for a vehicle according to claim 3 or 4, characterized by, before the determination of the slip ratio of the target wheel, further comprising:
judging whether the brake wheel cylinder pressure of the target wheel is maintained at present;
if the brake wheel cylinder pressure of the target wheel is not currently maintained, further determining whether the slip rate of the target wheel is greater than a third slip rate threshold, wherein the third slip rate threshold is greater than the second slip rate threshold and less than the first slip rate threshold;
maintaining a brake cylinder pressure of the target wheel if the slip ratio of the target wheel is greater than the third slip ratio threshold.
6. The brake control method of the vehicle according to claim 5, characterized in that when the slip ratio of the target wheel is larger than the second slip ratio threshold value and smaller than the first slip ratio threshold value, the brake cylinder pressure of the target wheel is continuously maintained.
7. A non-transitory computer-readable storage medium having stored thereon a computer program, characterized in that the program, when executed by a processor, implements a braking control method of a vehicle according to any one of claims 1-6.
8. A brake control apparatus for a vehicle, characterized by comprising:
the first judgment module is used for judging the slip rate of a target wheel when the vehicle enters a braking state;
the obtaining module is used for obtaining the pressure of a brake master cylinder of the vehicle when the first judging module judges that the slip ratio of the target wheel is larger than a first slip ratio threshold value or smaller than a second slip ratio threshold value, wherein the second slip ratio threshold value is smaller than the first slip ratio threshold value;
the second judgment module is used for judging whether the pressure of the brake master cylinder is greater than a first pressure threshold value in real time;
the timing module is used for timing the time that the pressure of the brake master cylinder is continuously greater than the first pressure threshold when the second judging module judges that the pressure of the brake master cylinder is greater than the first pressure threshold;
the control module is used for controlling the pressure of a brake wheel cylinder of the target wheel according to a first braking force difference threshold value when the timing time does not reach a first preset time, and controlling the pressure of the brake wheel cylinder of the target wheel according to a second braking force difference threshold value after the timing time reaches the first preset time, wherein the first braking force difference threshold value is smaller than the second braking force difference threshold value.
9. The brake control apparatus for a vehicle according to claim 8, wherein the control module directly controls a wheel cylinder pressure of the target wheel according to the first braking force difference threshold value when the second determination module determines that the master cylinder pressure is equal to or less than the first pressure threshold value.
10. The brake control apparatus for a vehicle according to claim 8, wherein when the first determination module determines that the slip ratio of the target wheel is less than the second slip ratio threshold, the control module is configured to:
obtaining the current brake cylinder pressure of the target wheel and the brake cylinder pressure of the coaxial wheel of the target wheel;
calculating an absolute value of a difference value between the brake cylinder pressure of the target wheel and the brake cylinder pressure of the coaxial wheel of the target wheel to obtain a braking force difference;
judging whether the braking force difference is greater than the first braking force difference threshold value/a second braking force difference threshold value;
increasing a brake wheel cylinder pressure of the target wheel if the braking force difference is less than or equal to the first/second braking force difference threshold values;
if the braking force difference is larger than the first braking force difference threshold value/second braking force difference threshold value, further judging whether the brake cylinder pressure of the target wheel is larger than the brake cylinder pressure of the coaxial wheel of the target wheel;
maintaining the brake cylinder pressure of the target wheel if the brake cylinder pressure of the target wheel is greater than the brake cylinder pressure of the coaxial wheel of the target wheel;
and if the brake cylinder pressure of the target wheel is less than or equal to the brake cylinder pressure of the coaxial wheel of the target wheel, increasing the brake cylinder pressure of the target wheel.
11. The brake control apparatus for a vehicle according to claim 8, wherein when the first determination module determines that the slip ratio of the target wheel is greater than the first slip ratio threshold, the control module is configured to:
obtaining the current brake cylinder pressure of the target wheel and the brake cylinder pressure of the coaxial wheel of the target wheel;
calculating an absolute value of a difference value between the brake cylinder pressure of the target wheel and the brake cylinder pressure of the coaxial wheel of the target wheel to obtain a braking force difference;
judging whether the braking force difference is greater than the first braking force difference threshold value/a second braking force difference threshold value;
reducing a brake wheel cylinder pressure of the target wheel if the braking force difference is less than or equal to the first/second braking force difference threshold values;
if the braking force difference is greater than the first/second braking force difference threshold, further determining whether a brake cylinder pressure of the target wheel is less than a brake cylinder pressure of a coaxial wheel of the target wheel;
if the brake cylinder pressure of the target wheel is smaller than the brake cylinder pressure of the coaxial wheel of the target wheel, reducing the brake cylinder pressure of the target wheel and reducing the brake cylinder pressure of the coaxial wheel of the target wheel;
and if the brake cylinder pressure of the target wheel is larger than or equal to the brake cylinder pressure of the coaxial wheel of the target wheel, reducing the brake cylinder pressure of the target wheel.
12. The brake control apparatus of a vehicle according to claim 10 or 11, characterized by further comprising third determination means for determining whether the control means currently holds the brake cylinder pressure of a target wheel before the first determination means determines the slip ratio of the target wheel, wherein,
the first judgment module further judges whether the slip rate of the target wheel is greater than a third slip rate threshold value if the third judgment module judges that the brake cylinder pressure of the target wheel is not currently maintained, and the control module maintains the brake cylinder pressure of the target wheel when the first judgment module judges that the slip rate of the target wheel is greater than the third slip rate threshold value, wherein the third slip rate threshold value is greater than the second slip rate threshold value and smaller than the first slip rate threshold value.
13. The brake control apparatus of a vehicle according to claim 12, characterized in that the control module continues to maintain the brake cylinder pressure of the target wheel when the first determination module determines that the slip ratio of the target wheel is greater than the second slip ratio threshold and less than the first slip ratio threshold.
14. A vehicle characterized by comprising a brake control apparatus of a vehicle according to any one of claims 8 to 13.
CN201711332637.0A 2017-12-13 2017-12-13 Vehicle and brake control method and device thereof Active CN109910850B (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN201711332637.0A CN109910850B (en) 2017-12-13 2017-12-13 Vehicle and brake control method and device thereof
PCT/CN2018/120594 WO2019114752A1 (en) 2017-12-13 2018-12-12 Vehicle, brake control method and apparatus therefor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201711332637.0A CN109910850B (en) 2017-12-13 2017-12-13 Vehicle and brake control method and device thereof

Publications (2)

Publication Number Publication Date
CN109910850A CN109910850A (en) 2019-06-21
CN109910850B true CN109910850B (en) 2020-06-19

Family

ID=66820730

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201711332637.0A Active CN109910850B (en) 2017-12-13 2017-12-13 Vehicle and brake control method and device thereof

Country Status (2)

Country Link
CN (1) CN109910850B (en)
WO (1) WO2019114752A1 (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111137263B (en) * 2019-12-26 2022-11-18 的卢技术有限公司 Vehicle braking stability control method and system
CN112298141B (en) * 2020-02-26 2021-10-15 中国地质大学（北京） Control method of whole vehicle brake system
CN112629738A (en) * 2020-12-18 2021-04-09 舜泰汽车有限公司 Unmanned vehicle braking force calibration system
CN113135191B (en) * 2021-05-20 2022-11-18 北京理工大学 Tracked vehicle slip rate estimation method based on road surface classification and machine learning
CN113858963B (en) * 2021-09-15 2023-04-07 东风柳州汽车有限公司 Braking method, system, medium and vehicle-mounted terminal based on electric vehicle

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102171076A (en) * 2008-12-26 2011-08-31 株式会社小松制作所 Traction control device
CN103826943A (en) * 2011-09-29 2014-05-28 丰田自动车株式会社 Vehicle brake control apparatus and brake control method
CN104169140A (en) * 2012-03-16 2014-11-26 丰田自动车株式会社 Brake force regulator
JP5978943B2 (en) * 2012-11-20 2016-08-24 日産自動車株式会社 Braking control device
CN106314163A (en) * 2016-08-26 2017-01-11 北京长城华冠汽车科技股份有限公司 Braking control method and device of electric vehicle

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005082081A (en) * 2003-09-10 2005-03-31 Advics:Kk Brake control device for vehicle
JP4696950B2 (en) * 2006-02-15 2011-06-08 株式会社アドヴィックス Brake control device for vehicle
JP4618169B2 (en) * 2006-03-13 2011-01-26 株式会社アドヴィックス Brake control device for vehicle
CN102490707B (en) * 2011-12-15 2015-06-10 奇瑞汽车股份有限公司 Brake control method
CN103661334B (en) * 2013-12-20 2015-11-11 北京万得嘉瑞汽车技术有限公司 A kind of control method of vehicle electronics brakig force distribution
CN106218616B (en) * 2016-08-02 2019-02-05 天津英创汇智汽车技术有限公司 A kind of ESC system and its control method of no pressure sensor

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102171076A (en) * 2008-12-26 2011-08-31 株式会社小松制作所 Traction control device
CN103826943A (en) * 2011-09-29 2014-05-28 丰田自动车株式会社 Vehicle brake control apparatus and brake control method
CN104169140A (en) * 2012-03-16 2014-11-26 丰田自动车株式会社 Brake force regulator
JP5978943B2 (en) * 2012-11-20 2016-08-24 日産自動車株式会社 Braking control device
CN106314163A (en) * 2016-08-26 2017-01-11 北京长城华冠汽车科技股份有限公司 Braking control method and device of electric vehicle

Also Published As

Publication number Publication date
WO2019114752A1 (en) 2019-06-20
CN109910850A (en) 2019-06-21

Similar Documents

Publication Publication Date Title
CN109910850B (en) Vehicle and brake control method and device thereof
EP1426258B1 (en) Behaviour control system for vehicle
US6185497B1 (en) Apparatus for controlling behavior of vehicle using brakes
US8108106B2 (en) Motion control system for vehicle
CN108128306B (en) Vehicle and steering instability control method and system thereof
JP2005271822A (en) Vehicular automatic deceleration control device
JP4534742B2 (en) Rollover suppression control device for vehicle
US8930111B2 (en) Braking force control apparatus and braking force control method for vehicle
EP2075144B1 (en) Wheel attitude control method and wheel attitude control device
JP4006573B2 (en) Vehicle control device
JP4927919B2 (en) Vehicle control device
JP4005669B2 (en) Braking force control device
AU778243B2 (en) Braking force control-type behavior control apparatus and method of motor vehicle
US20040128052A1 (en) Vehicular antiskid control apparatus and antiskid control method
JP5180934B2 (en) Vehicle braking device
JP5447447B2 (en) Braking force control device for vehicle
KR101307851B1 (en) Electronic Brake Force Distribution system and method for controlling the same
CN112208500A (en) Motor vehicle stability control method, electronic control unit and system
JP2005521585A (en) Method and apparatus for detecting malfunction of brake system of automobile
JP4600217B2 (en) Brake control device for vehicle
JP3680928B2 (en) Friction coefficient estimation device for road surface
CN108116270B (en) Vehicle instability control method, vehicle instability control device and vehicle
CN114919551B (en) Brake control method and device and vehicle
JP3729727B2 (en) Friction coefficient estimation device for road surface
JP2018069913A (en) Controller of vehicle

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant
TR01 Transfer of patent right
TR01 Transfer of patent right

Effective date of registration: 20211013

Address after: 518122 Room 301, complex building, 6531 Pingshan Avenue, Shatian community, Kengzi street, Pingshan District, Shenzhen City, Guangdong Province

Patentee after: Fudi Power Co.,Ltd.

Address before: 518118 BYD Road, Pingshan New District, Shenzhen, Guangdong 3009

Patentee before: BYD Co.,Ltd.