A brake torque calibration method, device, equipment and storage medium

Abstract

The application provides a brake torque calibration method, device, equipment and storage medium, relates to the field of new energy vehicle control, and the method comprises the following steps: obtaining a first brake power according to vehicle operation data; the vehicle speed is divided into intervals, and the first brake energy proportion of different vehicle speed intervals is generated; a fitting curve is generated according to the first brake energy proportion of different vehicle speed intervals, a first vehicle speed is obtained, and the fitting curve is taken as a torque coefficient-vehicle speed change curve; the brake intensity determined based on the vehicle operation data is divided into intervals, and the second brake energy proportion of different brake intensity intervals is obtained; the maximum value of the brake intensity range is determined; the electric brake torque corresponding to different vehicle speeds and brake pedal opening degrees is determined according to the maximum value of the brake intensity range, the first vehicle speed and the torque coefficient-vehicle speed change curve. The scheme realizes effective balance among the safety, comfort and economy of the brake system.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of new energy vehicle control, and particularly relates to a brake torque calibration method, device, equipment and storage medium. BACKGROUND

[0002] In a new energy vehicle, a mechanical friction braking system and an electric regenerative braking exist simultaneously, which is a hybrid braking system. In an urban driving condition, about 40% or even more driving energy is lost in the braking process, and the braking energy recovery potential is huge. Energy recovery plays an important role in improving energy utilization efficiency, prolonging the cruising range and reducing energy waste. The braking energy recovery effect is limited by the type of braking system, braking safety regulations, driving comfort, motor system and battery system. The difficulty of braking energy recovery technology application lies in the coordinated distribution of motor feedback braking force and original friction braking force, and finally the braking energy is recovered to the maximum extent without affecting the braking process and ensuring the braking performance. However, the existing brake torque calibration method of the braking energy recovery strategy cannot effectively balance the safety, comfort and economy of the braking system, and has the problem of low vehicle control precision. SUMMARY

[0003] The present application aims to at least solve the technical problems existing in the prior art. To this end, the present application proposes a brake torque calibration method in the first aspect, which comprises:

[0004] obtaining a first braking power according to vehicle operation data; the vehicle operation data comprises vehicle acceleration, vehicle operating mass, vehicle wind area, air resistance coefficient and tire rolling resistance coefficient;

[0005] dividing the vehicle speed into intervals, and generating a first braking energy proportion in different vehicle speed intervals based on the first braking power;

[0006] generating a fitting curve according to the first braking energy proportion in different vehicle speed intervals, obtaining a first vehicle speed corresponding to a maximum first braking energy proportion, and taking the fitting curve as a torque coefficient-vehicle speed change curve;

[0007] dividing the braking intensity determined based on the vehicle operation data into intervals, and obtaining a second braking energy proportion in different braking intensity intervals according to the first braking power;

[0008] determining a maximum braking intensity range value based on the second braking energy proportion in different braking intensity intervals;

[0009] determining an electric braking torque corresponding to different vehicle speeds and brake pedal opening degrees according to the maximum braking intensity range value, the first vehicle speed and the torque coefficient-vehicle speed change curve.

[0010] Optionally, the determining the electric braking torque corresponding to different vehicle speeds and brake pedal opening degrees according to the maximum value of the braking intensity range, the first vehicle speed and the torque coefficient-vehicle speed variation curve comprises:

[0011] obtaining the electric braking torque corresponding to different brake pedal opening degrees and the first vehicle speed according to the maximum value of the braking intensity range and the first vehicle speed;

[0012] obtaining the torque coefficient of the first vehicle speed based on the torque coefficient-vehicle speed variation curve and the first vehicle speed;

[0013] obtaining the torque coefficient of different vehicle speeds based on the torque coefficient-vehicle speed variation curve;

[0014] obtaining the electric braking torque corresponding to different vehicle speeds and brake pedal opening degrees according to the electric braking torque corresponding to different brake pedal opening degrees and the first vehicle speed, the torque coefficient of the first vehicle speed and the torque coefficient of different vehicle speeds.

[0015] Optionally, the electric braking torque corresponding to different vehicle speeds and brake pedal opening degrees is expressed as:

[0016]

[0017] wherein, is the electric braking torque corresponding to different vehicle speeds and brake pedal opening degrees, is the electric braking torque corresponding to different brake pedal opening degrees and the first vehicle speed is the torque coefficient of different vehicle speeds is the torque coefficient of the first vehicle speed .

[0018] Optionally, the interval division of vehicle speed and the generation of the first braking energy proportion of different vehicle speed intervals based on the first braking power comprise:

[0019] interval division of vehicle speed and integration of the first braking power of different vehicle speed intervals to obtain the first braking energy of different vehicle speed intervals;

[0020] obtaining the first braking energy proportion of different vehicle speed intervals according to the first braking energy of different vehicle speed intervals.

[0021] Optionally, the interval division of braking intensity determined based on vehicle operation data and the obtaining of the second braking energy proportion of different braking intensity intervals according to the first braking power comprise:

[0022] ​​The braking intensity determined based on the vehicle operation data is divided into intervals, and the first braking power in different braking intensity intervals is integrated to obtain second braking energy in different braking intensity intervals;

[0023] The second braking energy in different braking intensity intervals is obtained according to the second braking energy in different braking intensity intervals.

[0024] Optionally, the determination of the maximum braking intensity range based on the second braking energy ratio in different braking intensity intervals comprises:

[0025] A preset second braking energy ratio and a threshold value are obtained according to the second braking energy ratio in different braking intensity intervals, and the corresponding braking intensity range when the second braking energy ratio and threshold value is the preset second braking energy ratio and threshold value; the second braking energy ratio and threshold value is greater than or equal to 95%;

[0026] The maximum braking intensity range is determined according to the braking intensity range.

[0027] Optionally, the first braking power obtained according to the vehicle operation data comprises:

[0028] The vehicle driving power is obtained according to the vehicle operation data;

[0029] The first braking power is obtained by screening the vehicle driving power.

[0030] The second aspect of the present application proposes a brake torque calibration device, the device comprises:

[0031] The first data processing unit is used for obtaining the first braking power according to the vehicle operation data; the vehicle operation data comprises the whole vehicle acceleration, the whole vehicle operating mass, the vehicle windward area, the air resistance coefficient, and the tire rolling resistance coefficient;

[0032] The second data processing unit is used for dividing the vehicle speed into intervals, and generating the first braking energy ratio in different vehicle speed intervals based on the first braking power;

[0033] The third data processing unit is used for generating a fitting curve according to the first braking energy ratio in different vehicle speed intervals, obtaining the first vehicle speed corresponding to the maximum first braking energy ratio, and taking the fitting curve as a torque coefficient-vehicle speed change curve;

[0034] The fourth data processing unit is used for dividing the braking intensity determined based on the vehicle operation data into intervals, and obtaining the second braking energy ratio in different braking intensity intervals according to the first braking power;

[0035] The fifth data processing unit is configured to determine a maximum braking intensity range value based on the second braking energy proportion of the different braking intensity intervals.

[0036] The torque calibration unit is configured to determine the electric braking torque corresponding to different vehicle speeds and brake pedal opening degrees according to the maximum braking intensity range value, the first vehicle speed, and the torque coefficient-vehicle speed variation curve.

[0037] The third aspect of the present application provides an electronic device, which comprises a processor and a memory, and the memory stores at least one instruction or at least one program, and the at least one instruction or at least one program is loaded and executed by the processor to realize the brake torque calibration method according to the first aspect.

[0038] The fourth aspect of the present application provides a computer readable storage medium, which stores at least one instruction or at least one program, and the at least one instruction or at least one program is loaded and executed by the processor to realize the brake torque calibration method according to the first aspect.

[0039] The brake torque calibration method, device, equipment and storage medium have the beneficial effects that: the scheme combines vehicle operation data to obtain the distribution change rule of the braking energy proportion with the vehicle speed and the braking intensity, and the braking energy recovery torque of different vehicle models is customized and optimized according to the rule, the effective balance among the safety, comfort and economy of the braking system is realized, the vehicle control precision is improved, and the vehicle driving safety is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 A flowchart of a brake torque calibration method provided by the embodiment of the present application;

[0041] Figure 2 A first braking energy proportion diagram of a vehicle speed interval in the embodiment of the present application;

[0042] Figure 3 A vehicle speed-first braking energy proportion fitting curve diagram in the embodiment of the present application;

[0043] Figure 4 A second braking energy proportion diagram of a braking intensity interval in the embodiment of the present application;

[0044] Figure 5 A two-dimensional table diagram of the electric braking torque with the vehicle speed and the brake pedal opening degree in the embodiment of the present application. DETAILED DESCRIPTION

[0045] Clearly, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments of the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0046] Hereinafter, the terms "first" and "second" are only used for description purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first" and "second" can explicitly or implicitly include one or more of the features. In the description of the embodiments of the present disclosure, unless otherwise specified, the meaning of "a plurality of" is two or more. In addition, the use of "based on" or "according to" means openness and inclusiveness, because the process, step, calculation or other action "based on" or "according to" one or more stated conditions or values can be based on additional conditions or values beyond the stated values in practice.

[0047] The embodiments of the present application provide a brake torque calibration method, as shown in the method can include the following steps: Figure 1

[0048] Step 101, obtaining a first brake power according to vehicle operation data; the vehicle operation data includes vehicle acceleration, vehicle operating mass, vehicle wind area, air resistance coefficient, tire rolling resistance coefficient.

[0049] In a possible implementation, the first brake power obtained according to the vehicle operation data includes:

[0050] Obtaining vehicle driving power according to the vehicle operation data;

[0051] Filtering the vehicle driving power to obtain the first brake power.

[0052] Specifically, according to the actual operation data of the operating vehicle, the vehicle speed signal is extracted, and the vehicle driving power is calculated according to the following expression:

[0053]

[0054] Wherein, P is the vehicle driving power, the unit is kW, M is the vehicle operating mass, the unit is kg, g is the acceleration of gravity, the unit is m / s 2 , f is the tire rolling resistance coefficient, C d is the air resistance coefficient, A is the vehicle wind area, the unit is m 2 , V is the vehicle speed, the unit is km / h, δ is the vehicle rotational mass conversion coefficient, a is the vehicle acceleration, the unit is m / s 2 .​

[0055] The vehicle's driving power is screened, and the driving power less than 0 is the first braking power.

[0056] Step 102: Divide the vehicle speed into intervals and generate the first braking energy percentage for different vehicle speed intervals based on the first braking power.

[0057] In one possible implementation, the step of dividing the vehicle speed into intervals and generating a first braking energy percentage for different vehicle speed intervals based on the first braking power includes:

[0058] The vehicle speed is divided into intervals, and the first braking power in different speed intervals is integrated to obtain the first braking energy in different speed intervals.

[0059] The percentage of the first braking energy in different speed ranges is obtained based on the first braking energy in the different speed ranges.

[0060] Specifically, the expression for the first braking energy in different speed ranges is as follows:

[0061]

[0062] in, The first braking energy is given in different speed ranges, and the unit is kWh. This is the first braking power.

[0063] The first braking energy is analyzed in different speed ranges to obtain the proportion of first braking energy in different speed ranges. For example, such as... Figure 2 As shown, 0 can be extracted separately. 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 The first braking energy percentage, Figure 2 The proportion of braking energy in the first braking energy is the percentage of braking energy in the second braking energy.

[0064] Step 103: Generate a fitting curve based on the first braking energy percentage in the different vehicle speed ranges, obtain the first vehicle speed corresponding to the maximum first braking energy percentage, and use the fitting curve as the torque coefficient-vehicle speed change curve.

[0065] Specifically, as shown in Figure 3 , the vehicle speed-first brake energy ratio fitting curve is extracted according to the distribution of the first brake energy ratio with the vehicle speed interval, and the vehicle speed corresponding to the maximum first brake energy ratio can be obtained according to the fitting curve, which is the first vehicle speed. Wherein, Figure 3 The brake energy ratio in the formula is the first brake energy ratio. In addition, the fitting curve is taken as the torque coefficient-vehicle speed change curve in the brake torque optimization algorithm, and the formula of the fitting curve is taken as the torque coefficient-vehicle speed formula, and the expression of the formula is as follows:

[0066]

[0067] Wherein, is the torque coefficient, a, b, and c are parameters in the torque coefficient-vehicle speed formula, and n is the number of polynomials.

[0068] Step 104, interval division is performed on the brake intensity determined based on the vehicle operation data, and the second brake energy ratio of different brake intensity intervals is obtained according to the first brake power.

[0069] In one possible implementation, the interval division is performed on the brake intensity determined based on the vehicle operation data, and the second brake energy ratio of different brake intensity intervals is obtained according to the first brake power, including:

[0070] Interval division is performed on the brake intensity determined based on the vehicle operation data, and the first brake power of different brake intensity intervals is integrated to obtain the second brake energy of different brake intensity intervals;

[0071] The second brake energy of different brake intensity intervals is obtained according to the second brake energy of different brake intensity intervals.

[0072] Specifically, assuming that the brake intensity is Z, as shown in Figure 4 , the second brake energy ratios of 0 , , , , , 0.05 , , , , , and Figure 4 other brake intensity intervals can be extracted respectively. Wherein, Figure 4 The brake energy ratio in the formula is the second brake energy ratio.

[0073] Step 105, determining a maximum braking intensity range value based on the second braking energy proportion of the different braking intensity intervals.

[0074] In a possible implementation, the determining of the maximum braking intensity range value based on the second braking energy proportion of the different braking intensity intervals comprises:

[0075] a preset second braking energy proportion and threshold value, a second braking energy proportion and corresponding to the preset second braking energy proportion and threshold value is obtained according to the second braking energy proportion of the different braking intensity intervals; the second braking energy proportion and threshold value is greater than or equal to 95%;

[0076] determining the maximum braking intensity range value according to the braking intensity range.

[0077] Exemplarily, when the second braking energy proportion and threshold value is 95%, the braking intensity range corresponding to the second braking energy proportion and of 95% can be obtained , which is a main distribution interval of the kinetic energy of the vehicle consumed by the braking system, and should be considered in the electric braking torque calibration process. The maximum braking intensity range value can be obtained through the braking intensity range.

[0078] Step 106, determining the electric braking torque corresponding to different vehicle speeds and brake pedal opening degrees according to the maximum braking intensity range value, the first vehicle speed and the torque coefficient-vehicle speed change curve.

[0079] In a possible implementation, the determining of the electric braking torque corresponding to different vehicle speeds and brake pedal opening degrees according to the maximum braking intensity range value, the first vehicle speed and the torque coefficient-vehicle speed change curve comprises:

[0080] obtaining the electric braking torque corresponding to the first vehicle speed and different brake pedal opening degrees according to the maximum braking intensity range value and the first vehicle speed;

[0081] obtaining the torque coefficient of the first vehicle speed based on the torque coefficient-vehicle speed change curve and the first vehicle speed;

[0082] obtaining the torque coefficient of different vehicle speeds based on the torque coefficient-vehicle speed change curve;

[0083] obtaining the electric braking torque corresponding to different vehicle speeds and brake pedal opening degrees according to the electric braking torque corresponding to the first vehicle speed and different brake pedal opening degrees, the torque coefficient of the first vehicle speed and the torque coefficient of different vehicle speeds.

[0084] In a possible implementation, the expression of the electric braking torque corresponding to different vehicle speeds and brake pedal opening degrees is:

[0085]

[0086] wherein, corresponding to different vehicle speeds corresponding to different brake pedal opening degrees, i.e., different vehicle speeds corresponding to different brake pedal opening degrees, unit: Nm, is a first vehicle speed corresponding to different brake pedal opening degrees, corresponding to different vehicle speeds is a torque coefficient, is a torque coefficient of a first vehicle speed .

[0087] wherein, the electric brake torque corresponding to the first vehicle speed and different brake pedal opening degrees i.e., the electric brake torque corresponding to the first vehicle speed at different brake pedal opening degrees, and the expression is:

[0088]

[0089] wherein, unit: Nm, is a maximum value of brake intensity range, is a front axle mechanical brake force under a certain brake pedal opening degree, unit: N, is a rear axle mechanical brake force under a certain brake pedal opening degree, unit: N, R is a tire rolling radius, unit: m, and i is a speed ratio of a power transmission system, is a transmission system efficiency, and M is a whole vehicle operating mass.

[0090] Through the above method, a two-dimensional table of electric brake torque with vehicle speed and brake pedal opening degree can be finally obtained, as shown in Table 1. Figure 5 wherein, Figure 5 the brake opening degree in Table 1 is a brake pedal opening degree.

[0091] In the embodiment of the application, the distribution change rule of brake energy proportion with vehicle speed and brake intensity is obtained in combination with vehicle operation data, and the brake energy recovery torque of different vehicle models is customized and optimized according to the rule, so that the effective balance among safety, comfort and economy of the brake system is realized, the vehicle control precision is improved, and the vehicle driving safety is ensured.

[0092] The embodiment of the application further provides a brake torque calibration device, which comprises:

[0093] a first data processing unit, configured to obtain a first brake power according to vehicle operation data; the vehicle operation data comprises whole vehicle acceleration, whole vehicle operating mass, vehicle wind area, air resistance coefficient, and tire rolling resistance coefficient;

[0094] a second data processing unit, configured to divide a vehicle speed into intervals, and generate a first braking energy proportion of different vehicle speed intervals based on the first braking power;

[0095] a third data processing unit, configured to generate a fitting curve according to the first braking energy proportions of the different vehicle speed intervals, obtain a first vehicle speed corresponding to a maximum first braking energy proportion, and use the fitting curve as a torque coefficient-vehicle speed change curve;

[0096] a fourth data processing unit, configured to divide braking intensities determined based on vehicle operation data into intervals, and obtain second braking energy proportions of different braking intensity intervals according to the first braking power;

[0097] a fifth data processing unit, configured to determine a maximum braking intensity range value based on the second braking energy proportions of the different braking intensity intervals;

[0098] a torque calibration unit, configured to determine electric braking torques corresponding to different vehicle speeds and brake pedal opening degrees according to the maximum braking intensity range value, the first vehicle speed, and the torque coefficient-vehicle speed change curve.

[0099] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the device described above can refer to the corresponding process in the foregoing method embodiments, and will not be described here.

[0100] In another embodiment provided by the present application, an electronic device is provided, which includes a processor and a memory, the memory storing at least one instruction or at least one program, the at least one instruction or at least one program being loaded and executed by the processor to implement the braking torque calibration method proposed in the embodiments of the present application.

[0101] In another embodiment provided by the present application, a computer readable storage medium is provided, the storage medium storing at least one instruction or at least one program, the at least one instruction or at least one program being loaded and executed by a processor to implement the braking torque calibration method proposed in the embodiments of the present application.

[0102] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto, any change or replacement within the technical scope disclosed by the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for calibrating braking torque, characterized in that, include: The vehicle's driving power is obtained from the vehicle's operating data; The vehicle driving power is filtered to obtain the first braking power; the vehicle operating data includes vehicle acceleration, vehicle operating mass, vehicle frontal area, air drag coefficient, and tire rolling resistance coefficient. The vehicle speed is divided into intervals, and the first braking energy ratio of different vehicle speed intervals is generated based on the first braking power. Based on the first braking energy percentage of the different vehicle speed ranges, a fitting curve is generated to obtain the first vehicle speed corresponding to the maximum first braking energy percentage, and the fitting curve is used as the torque coefficient-vehicle speed change curve. The braking intensity determined based on vehicle operation data is divided into intervals, and the second braking energy ratio of different braking intensity intervals is obtained according to the first braking power. The maximum value of the braking intensity range is determined based on the proportion of the second braking energy in the different braking intensity ranges; The electric braking torque corresponding to different vehicle speeds and brake pedal openings is determined based on the maximum value of the braking intensity range, the first vehicle speed, and the torque coefficient-vehicle speed variation curve.

2. The braking torque calibration method according to claim 1, characterized in that, The step of determining the electric braking torque corresponding to different vehicle speeds and brake pedal openings based on the maximum value of the braking intensity range, the first vehicle speed, and the torque coefficient-vehicle speed variation curve includes: Based on the maximum value of the braking intensity range and the first vehicle speed, the first vehicle speed and the electric braking torque corresponding to different brake pedal openings are obtained. The torque coefficient at the first vehicle speed is obtained based on the torque coefficient-vehicle speed variation curve and the first vehicle speed. The torque coefficient at different vehicle speeds is obtained based on the torque coefficient-vehicle speed variation curve. The electric braking torque corresponding to different vehicle speeds and brake pedal openings is obtained based on the first vehicle speed and the electric braking torque corresponding to different brake pedal openings, the torque coefficient of the first vehicle speed, and the torque coefficients of the different vehicle speeds.

3. The braking torque calibration method according to claim 2, characterized in that, The expression for the electric braking torque corresponding to different vehicle speeds and brake pedal openings is as follows: in, For different vehicle speeds The electric braking torque corresponding to the brake pedal opening. First speed And the electric braking torque corresponding to different brake pedal openings, For different vehicle speeds torque coefficient, First speed The torque coefficient.

4. The braking torque calibration method according to claim 1, characterized in that, The step of dividing the vehicle speed into intervals and generating the first braking energy percentage for different vehicle speed intervals based on the first braking power includes: The vehicle speed is divided into intervals, and the first braking power in different speed intervals is integrated to obtain the first braking energy in different speed intervals. The percentage of the first braking energy in different speed ranges is obtained based on the first braking energy in the different speed ranges.

5. The braking torque calibration method according to claim 1, characterized in that, The step of dividing the braking intensity determined based on vehicle operating data into intervals and obtaining the second braking energy percentage for different braking intensity intervals according to the first braking power includes: The braking intensity determined based on vehicle operation data is divided into intervals, and the first braking power in different braking intensity intervals is integrated to obtain the second braking energy in different braking intensity intervals. The percentage of the second braking energy in different braking intensity ranges is obtained based on the second braking energy in the different braking intensity ranges.

6. The braking torque calibration method according to claim 1, characterized in that, The determination of the maximum value of the braking intensity range based on the second braking energy ratio of the different braking intensity ranges includes: A second braking energy percentage and a threshold are preset. Based on the second braking energy percentages in different braking intensity ranges, the sum of second braking energy percentages corresponding to different braking intensity ranges is calculated. The braking intensity range corresponding to when the sum of second braking energy percentages equals the threshold is determined; wherein, the threshold is greater than or equal to 95%. The maximum value of the braking intensity range is determined based on the braking intensity range.

7. A braking torque calibration device, characterized in that, The device includes: The first data processing unit is used to obtain the vehicle driving power based on the vehicle operating data; and to filter the vehicle driving power to obtain the first braking power; the vehicle operating data includes vehicle acceleration, vehicle operating mass, vehicle frontal area, air drag coefficient, and tire rolling resistance coefficient. The second data processing unit is used to divide the vehicle speed into intervals and generate the first braking energy ratio of different vehicle speed intervals based on the first braking power. The third data processing unit is used to generate a fitting curve based on the first braking energy ratio of the different vehicle speed ranges, obtain the first vehicle speed corresponding to the maximum first braking energy ratio, and use the fitting curve as the torque coefficient-vehicle speed change curve. The fourth data processing unit is used to divide the braking intensity determined based on vehicle operation data into intervals and obtain the second braking energy ratio of different braking intensity intervals according to the first braking power. The fifth data processing unit is used to determine the maximum value of the braking intensity range based on the second braking energy ratio of the different braking intensity ranges; The torque calibration unit is used to determine the electric braking torque corresponding to different vehicle speeds and brake pedal openings based on the maximum value of the braking intensity range, the first vehicle speed, and the torque coefficient-vehicle speed variation curve.

8. An electronic device, characterized in that, The electronic device includes a processor and a memory, the memory storing at least one instruction or at least one program, the at least one instruction or at least one program being loaded and executed by the processor to implement the braking torque calibration method as described in any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, The storage medium stores at least one instruction or at least one program, which is loaded and executed by a processor to implement the braking torque calibration method as described in any one of claims 1-6.

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