Dynamic adjusting method and device for automobile braking force and automobile

Abstract

The invention discloses a dynamic adjusting method and device for automobile braking force and an automobile. The dynamic adjusting method comprises the steps that multiple pieces of brake pedal stroke data of the automobile and multiple pieces of deceleration data corresponding to the multiple pieces of brake pedal stroke data are obtained; formulating a relation table between brake pedal travel data and total target brake pressure according to the deceleration data; obtaining the total mass of the automobile and the estimated driving gradient of the automobile; correcting the total brake pressure according to the total mass, the estimated driving gradient and the deceleration data and generating a total target brake pressure; and according to the total target brake pressure, the front axle brake pressure, the rear axle brake pressure and the motor target brake torque of the automobile are determined. According to the dynamic adjustment method for the automobile braking force, dynamic adjustment of the braking force of the automobile under different loads and different slopes can be achieved, and the requirement for consistency of the braking force of a driver is met.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicles, and in particular to a method and device for dynamically adjusting the braking force of an automobile, and a vehicle. Background Art

[0002] The braking system is an important system on the vehicle and plays an important role in the driving safety of the vehicle. The traditional braking force control of the vehicle is usually related to the brake pedal travel, which is generally a fixed proportional relationship, that is, the driver generates the same braking force under the same brake pedal travel.

[0003] The weight of commercial vehicles varies greatly due to the different amounts of cargo they carry. With traditional braking force control, when the driver steps on the same brake pedal stroke, the braking deceleration of the vehicle will vary greatly under different vehicle weight changes, resulting in poor braking feel for the driver and even accidents. Summary of the invention

[0004] The dynamic adjustment method of the automobile braking force provided by the present invention adjusts the total target braking pressure by obtaining comprehensive information such as the total mass of the automobile, the estimated driving slope and the deceleration data, thereby realizing dynamic adjustment of the braking force of the vehicle under different loads and different slopes, and meeting the driver's demand for consistent braking feel.

[0005] According to a first aspect of the present invention, a method for dynamically adjusting the braking force of a vehicle is provided, comprising:

[0006] Acquire a plurality of brake pedal stroke data of the vehicle and a plurality of deceleration data corresponding to the plurality of brake pedal stroke data;

[0007] formulating a relationship table between brake pedal travel data and total target brake pressure according to the deceleration data;

[0008] Obtaining the total mass of the vehicle and the estimated driving slope of the vehicle;

[0009] modifying the total brake pressure according to the total mass, the estimated slope and the deceleration data and generating a total target brake pressure;

[0010] The front axle brake pressure, the rear axle brake pressure and the motor target braking torque of the vehicle are determined according to the total target braking pressure.

[0011] Optionally, a relationship table between the brake pedal travel data and the total target brake pressure is formulated according to the deceleration data, including:

[0012] determining a relationship table between the brake pedal stroke data and the total target braking force according to the brake pedal stroke data and the deceleration data;

[0013] The total target braking force is calculated by formula (1):

[0014] F tar_raw (k)=|m×a tar (k)| (1)

[0015] Among them, F tar_raw (k) is the total target braking force, m is the total mass of the vehicle under standard load, and a tar (k) is the deceleration of the vehicle.

[0016] Optionally, after determining the relationship table between the brake pedal stroke data and the total target braking force according to the brake pedal stroke data and the deceleration data, the method further comprises:

[0017] formulating a relationship table between the brake pedal stroke data and the total target braking pressure according to the brake pedal stroke data and the total target braking force;

[0018] The total target braking pressure is calculated by formula (2):

[0019] F tar_raw =A×p (2)

[0020] Among them, F tar_raw is the total target braking force, A is the braking effectiveness factor, and p is the total target braking pressure.

[0021] Optionally, obtaining the total mass of the vehicle and the estimated driving slope of the vehicle includes:

[0022] The total mass and the estimated driving slope are calculated by formula (3):

[0023]

[0024] Among them, T mot is the motor drive torque of the vehicle, i g is the speed ratio from the motor to the wheel end of the vehicle, η is the transmission efficiency, r is the tire radius, m is the total mass of the vehicle under standard load, g is the acceleration of gravity, f is the rolling resistance coefficient, α is the estimated driving slope, C d is the drag coefficient, A is the frontal area, v is the vehicle speed, δ is the rotational mass coefficient, and a is the acceleration.

[0025] Optionally, correcting the total braking pressure and generating a total target braking pressure according to the total mass, the estimated driving slope and the deceleration data includes:

[0026] Performing a primary correction on the total braking pressure according to the total mass, the estimated driving slope and the deceleration data of the vehicle and generating a primary target braking pressure;

[0027] The first-level target brake pressure is calculated by formula (4):

[0028]

[0029] Among them, m est is the estimated mass of the car, m is the total mass of the car under standard load, P tar_raw is the total braking pressure, α is the estimated driving slope, P tar_fix1 is the first-level target braking pressure, a is the deceleration data; wherein, P tar_raw Obtained by querying the relationship table.

[0030] Optionally, after performing a primary correction on the total braking pressure according to the total mass, the estimated slope and the deceleration data of the vehicle and generating a primary target braking pressure, the method further includes:

[0031] Obtaining the actual braking deceleration of the vehicle during the detection process;

[0032] The primary target braking pressure is corrected at a second level according to the relationship between the actual braking deceleration and the target braking deceleration to generate the total target braking pressure.

[0033] Optionally, performing a secondary correction on the primary target braking pressure according to the relationship between the actual braking deceleration and the target braking deceleration and generating the total target braking pressure includes:

[0034] When the actual braking deceleration is smaller than the target braking deceleration for n consecutive times, the first-level target braking pressure is corrected in a positive direction; or,

[0035] When the actual braking deceleration is greater than the target braking deceleration for n consecutive times, the first-level target braking pressure is negatively corrected; wherein the positive correction is performed by formula (5) and formula (6):

[0036] N(k)=N(k-1)×F P (5)

[0037] Among them, N(k) is the current correction coefficient, N(k-1) is the previous correction coefficient, and F p is the positive step correction factor, F p >1;

[0038] p tar_fix2 =p tar_fix1 ×N(k) (6)

[0039] Among them, P tar_fix2 is the total target braking pressure, Ptar_fix1 is the first-level target brake pressure;

[0040] The negative correction is performed by formula (7) and formula (8):

[0041] N(k)=N(k-1)×F N (7)

[0042] Among them, N(k) is the current correction coefficient, N(k-1) is the previous correction coefficient, and F N is the negative step correction coefficient, 0 <F N <1;

[0043] p tar_fix2 =p tar_fix1 ×N(k) (8)

[0044] Among them, P tar_fix2 is the total target braking pressure, P tar_fix1 is the first-level target braking pressure, and n is a positive integer greater than or equal to 2.

[0045] Optionally, determining the front axle brake pressure, the rear axle brake pressure and the motor target braking torque of the vehicle according to the total target braking pressure includes:

[0046] According to the ideal I curve of automobile theory, a relationship table of total target brake pressure, front axle brake pressure, and rear axle brake pressure is formulated; the available brake equivalent pressure value of the rear axle motor is determined by formula (9);

[0047] p MotMax =C×T mot_brmax | (9)

[0048] Among them, P MotMax is the equivalent braking pressure value of the rear axle motor, T mot_brmax is the available braking torque of the rear axle motor, C is the torque-pressure conversion coefficient,

[0049] When the available brake equivalent pressure value of the rear axle motor is greater than or equal to the rear axle brake pressure, the motor target braking torque is determined by formula (10):

[0050]

[0051] Among them, T Mot_Tar is the motor target braking torque, P rall_tar is the rear axle brake pressure, and the rear axle brake target pressure P r_tar = 0; or,

[0052] When the available brake equivalent pressure value of the rear axle motor is less than the rear axle brake pressure, the motor target braking torque is determined by formula (11):

[0053] T Mot_Tar =T mot_brmax (11)

[0054] The motor target braking torque is determined by formula (12):

[0055] p r_tar =p rall_tar -p MotMax (12)

[0056] Among them, P r_tar is the target braking torque of the motor.

[0057] According to a second aspect of the present invention, a dynamic adjustment device for automobile braking force is provided, wherein the dynamic adjustment device is used to perform the dynamic adjustment method for automobile braking force described in any one of the first aspects of the present invention, and the dynamic adjustment device comprises:

[0058] An acquisition module, used for acquiring a plurality of brake pedal travel data of the vehicle and a plurality of deceleration data corresponding to the plurality of brake pedal travel data;

[0059] a tabulation module, for formulating a relationship table between brake pedal travel data and total target brake pressure according to the deceleration data;

[0060] A correction module, used for obtaining the total mass of the vehicle and the estimated driving slope of the vehicle; correcting the total braking pressure according to the total mass, the estimated driving slope and the deceleration data and generating a total target braking pressure;

[0061] The allocation module is used to determine the front axle brake pressure, the rear axle brake pressure and the motor target braking torque of the vehicle according to the total target braking pressure.

[0062] According to a third aspect of the present invention, a vehicle is provided, characterized in that it comprises the device for dynamically adjusting the braking force of the vehicle as described in the second aspect of the present invention.

[0063] The present invention discloses a method, device and vehicle for dynamically adjusting the braking force of an automobile, comprising: obtaining a plurality of brake pedal travel data of an automobile and a plurality of deceleration data corresponding to the plurality of brake pedal travel data; formulating a relationship table between the brake pedal travel data and the total target braking pressure according to the deceleration data; obtaining the total mass of the automobile and the estimated driving slope of the automobile; correcting the total braking pressure and generating the total target braking pressure according to the total mass, the estimated driving slope and the deceleration data; determining the front axle brake pressure, the rear axle brake pressure and the motor target braking torque of the automobile according to the total target braking pressure. The method for dynamically adjusting the braking force of an automobile provided by the present invention adjusts the total target braking pressure by obtaining comprehensive information such as the total mass of the automobile, the estimated driving slope and the deceleration data, thereby realizing dynamic adjustment of the braking force of the vehicle under different loads and different slopes, and meeting the driver's demand for consistent braking feel.

[0064] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0066] Figure 1 It is a block diagram of an electronic hydraulic brake system in a method for dynamically adjusting the braking force of an automobile provided by an embodiment of the present invention;

[0067] Figure 2 This is a flow chart of a method for dynamically adjusting the braking force of an automobile provided by an embodiment of the present invention;

[0068] Figure 3 is a flow chart of another method for dynamically adjusting the braking force of an automobile provided by an embodiment of the present invention;

[0069] Figure 4 is a flow chart of another method for dynamically adjusting the braking force of an automobile provided by an embodiment of the present invention;

[0070] Figure 5 is a flow chart of another method for dynamically adjusting the braking force of an automobile provided by an embodiment of the present invention;

[0071] Figure 6 is a flow chart of another method for dynamically adjusting the braking force of an automobile provided by an embodiment of the present invention;

[0072] Figure 7 The invention is a block diagram of a dynamic adjustment device for automobile braking force provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0073] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0074] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0075] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0076] Figure 1 is a block diagram of an electronic hydraulic brake system in a method for dynamically adjusting the braking force of an automobile provided by an embodiment of the present invention, with reference to Figure 1, the brake pedal signal and the accelerator pedal signal are transmitted to the vehicle controller 18, and the vehicle controller 18 sends the signal to the front axle electronic hydraulic brake controller 1 through the controller area network (CAN) signal. The front axle electronic hydraulic brake controller 1 analyzes the brake pedal displacement signal, analyzes the total required target braking force, and distributes the total required target braking force into the front and rear axle target braking pressures, and sends the rear axle target braking force to the rear axle electronic hydraulic brake controller 2 through the CAN signal. The front axle electronic hydraulic controller 1 controls the front axle braking force motor 3 to output torque, and the front axle braking force motor 3 rotates to transmit power to the front axle braking force reduction mechanism 4, and the front axle braking force reduction mechanism 4 increases the torque of the front axle braking force motor 3 and converts the rotational motion into linear motion, pushing the piston in the front axle brake hydraulic cylinder 5 to generate hydraulic pressure, and transmits the hydraulic pressure to the left front wheel brake 6 and the right front wheel brake 7 through the hydraulic pipeline, respectively, to push the left and right front axle brakes to operate, and the front axle 10 is used to connect the left front wheel 16 and the right front wheel 17, so that the left front wheel 16 and the right front wheel 17 generate braking force. By controlling the output torque of the front axle braking force motor 3, different braking forces of the two front wheels can be achieved. After receiving the rear axle target braking pressure from the front axle electronic hydraulic brake controller 1, the rear axle target braking pressure is converted into the braking torque of the drive motor 12 and the braking pressure of the left and right rear wheel brakes through the braking distribution algorithm. The rear axle electronic hydraulic controller 2 controls the output braking torque of the control motor 12 through the CAN signal. The rear axle electronic hydraulic controller 2 controls the output torque of the rear axle braking force motor 19, and the rear axle braking force motor pushes the piston of the rear axle brake hydraulic cylinder 21 through the rear axle reduction mechanism 20 to generate brake fluid pressure. The brake fluid pressure is transmitted to the left rear wheel brake 8 and the right rear wheel brake 9 through the hydraulic pipeline, generating braking force for the left rear wheel 14 and the right rear wheel 15, and the differential 13 is used for precise steering of the car. The front axle brake hydraulic cylinder 5 and the rear axle brake hydraulic cylinder 21 are respectively provided with pressure sensors, which transmit the front and rear axle brake cylinder pressures to the front axle electronic hydraulic brake controller 1 and the rear axle electronic hydraulic brake controller 2 in real time. The drive motor 12 communicates with the vehicle controller 18, the front axle electronic hydraulic brake controller 1, and the rear axle electronic hydraulic brake controller 2 through CAN signals, and transmits the current motor torque signal to the vehicle controller 18, the front axle electronic hydraulic brake controller 1, and the rear axle electronic hydraulic brake controller 2.

[0077] Figure 2 is a flow chart of a method for dynamically adjusting the braking force of an automobile provided by an embodiment of the present invention, with reference to Figure 2 The embodiment of the present invention provides a method for dynamically adjusting the braking force of an automobile, comprising:

[0078] S1. Acquire a plurality of brake pedal stroke data of a vehicle and a plurality of deceleration data corresponding to the plurality of brake pedal stroke data.

[0079] Specifically, a vehicle is tested, and multiple brake pedal travel data of the vehicle and multiple deceleration data corresponding to the brake pedal travel data are obtained and tabulated. Table 1 is a relationship table between the brake pedal travel and the deceleration. As shown in Table 1, the specific tabulation steps are:

[0080] During the vehicle braking test, the calibration is performed in combination with the driver's subjective comfort evaluation feeling. The brake pedal stroke displacement s(k) is divided from 0 to the maximum brake mechanical stroke with a certain step size Δs, and the sampling points s(k)=k×Δs are divided respectively, where k is a positive integer greater than 0.

[0081] Brake pedal travel 0 s(1) s(k-1) s(k) Deceleration <![CDATA[a tar (0)]]> <![CDATA[a tar (1)]]> <![CDATA[a tar (k-1)]]> <![CDATA[a tar (k)]]>

[0082] Table 1

[0083] S2. Formulate a relationship table between the brake pedal travel data and the total target brake pressure according to the deceleration data.

[0084] Specifically, according to the brake pedal travel data and deceleration data acquired in the above step S1 and according to the relationship table shown in Table 1, a relationship table between the brake pedal travel data and the total target brake pressure is formulated.

[0085] S3. Obtain the total mass of the vehicle and the estimated driving slope of the vehicle.

[0086] Specifically, the total mass of the vehicle under different conditions and the estimated slope of the vehicle under different driving sections are obtained.

[0087] S4. Correct the total braking pressure according to the total mass, the estimated driving slope and the deceleration data and generate a total target braking pressure.

[0088] Specifically, the total brake pressure corresponding to different brake pedal strokes is queried in the total brake pressure table theoretically calculated in the above step S2, and the theoretical total brake pressure is dynamically corrected according to the total mass of the vehicle, the estimated driving slope and the deceleration data to generate the total target brake pressure. The total target brake pressure is the brake pressure required for the vehicle according to different brake pedal strokes during driving.

[0089] S5. Determine the front axle brake pressure, rear axle brake pressure and motor target braking torque of the vehicle according to the total target braking pressure.

[0090] Specifically, refer to Figure 1 and Figure 2The total target braking pressure determined in the above step S4 is respectively distributed to the front axle brake pressure of the vehicle (i.e., including the left front wheel brake 6 and the right front wheel brake 7), the rear axle brake pressure (i.e., the left rear wheel brake 8 and the right rear wheel brake 9) and the motor target braking torque (i.e., the target torque required by the drive motor 12).

[0091] On the basis of the above-mentioned embodiments of the invention, the embodiment of the invention further refines the relationship table between the brake pedal travel data and the total target brake pressure according to the deceleration data. Figure 3 is a flow chart of another method for dynamically adjusting the braking force of an automobile provided by an embodiment of the present invention, with reference to Figure 3 The method for dynamically adjusting the braking force of an automobile provided by an embodiment of the present invention includes:

[0092] S21. Acquire a plurality of brake pedal stroke data of the vehicle and a plurality of deceleration data corresponding to the brake pedal stroke data.

[0093] S22. Determine a relationship table between the brake pedal stroke data and the total target braking force according to the brake pedal stroke data and the deceleration data.

[0094] Specifically, the total target braking force is calculated by formula (1):

[0095] F tar_raw (k)=|m×a tar (k)| (1)

[0096] Among them, F tar_raw (k) is the total target braking force, m is the total mass of the vehicle under standard load, and a tar (k) is the deceleration of the car.

[0097] During the vehicle braking test, the calibration is performed in combination with the driver's subjective comfort evaluation feeling. The brake pedal travel displacement s(k) starts from 0 to the maximum brake mechanical travel, and the sampling points s(k)=k×Δs are divided with a certain step length Δs, where k is a positive integer greater than 0. Table 2 is drawn according to the above formula (I) and the brake pedal travel data. Table 2 is a relationship table between the brake pedal travel and the total target braking force, as shown in Table 2.

[0098] Brake pedal travel 0 s(1) s(k-1) s(k) Total target braking force <![CDATA[F tar_raw (0)]]> <![CDATA[F tar_raw (1)]]> <![CDATA[F tar_raw (k-1)]]> <![CDATA[F tar_raw (k)]]>

[0099] Table 2

[0100] S23. Formulate a relationship table between the brake pedal stroke data and the total target braking pressure according to the brake pedal stroke data and the total target braking force.

[0101] Specifically, the total target braking pressure is calculated by formula (2):

[0102]

[0103] Among them, F tar_raw is the total target braking force, A is the braking efficiency factor, and p is the total target braking pressure.

[0104] Table 3 is drawn according to Table 2 and formula (2) specified in the above step S22. Table 3 is a relationship table between the brake pedal stroke and the total target brake pressure, as shown in Table 3.

[0105] Brake pedal travel 0 s(1) s(k-1) s(k) Total target braking force <![CDATA[P tar_raw (0)]]> <![CDATA[P tar_raw (1)]]> <![CDATA[P tar_raw (k-1)]]> <![CDATA[P tar_raw (k)]]>

[0106] Table 3

[0107] S24. Obtain the total mass of the vehicle and the estimated driving slope of the vehicle.

[0108] S25. Correct the total braking pressure according to the total mass, the estimated driving slope and the deceleration data and generate a total target braking pressure.

[0109] S26. Determine the front axle brake pressure, rear axle brake pressure and motor target braking torque of the vehicle according to the total target braking pressure.

[0110] On the basis of the above-mentioned embodiments of the invention, the embodiments of the present invention further refine the acquisition of the total mass of the vehicle and the estimated driving slope of the vehicle. The method for dynamically adjusting the braking force of the vehicle provided by the embodiments of the present invention includes:

[0111] The total mass and estimated driving slope are calculated using formula (3):

[0112]

[0113] Among them, T mot is the motor drive torque of the vehicle, i g is the speed ratio from the motor to the wheel end of the car, η is the transmission efficiency, r is the tire radius, m is the total mass of the car under standard load, g is the acceleration of gravity, f is the rolling resistance coefficient, α is the estimated driving slope, C d is the drag coefficient, A is the frontal area, v is the vehicle speed, δ is the rotational mass coefficient, and a is the acceleration.

[0114] In the above formula (3), the motor driving torque is calculated by the motor controller in real time according to the motor current, the vehicle speed can be obtained by transforming the motor speed through the speed ratio from the motor to the wheel end of the car and the tire radius, and the vehicle acceleration is obtained by the vehicle speed difference after first-order filtering. The quantities to be estimated in formula (3) are the vehicle mass and the slope, and the remaining quantities are constants.

[0115] By collecting the motor torque, vehicle speed, and vehicle acceleration at a period of Δt, a series of equilibrium equations for the vehicle's driving force and resistance can be written. By using the least squares method for this series of equations, the vehicle mass m and slope α can be estimated.

[0116] Based on the above-mentioned embodiments of the invention, the embodiments of the invention further refine the correction of the total braking pressure and the generation of the total target braking pressure according to the total mass, the estimated driving slope and the deceleration data. Figure 4 is a flow chart of another method for dynamically adjusting the braking force of an automobile provided by an embodiment of the present invention, with reference to Figure 4 The dynamic adjustment method of automobile braking provided by the embodiment of the present invention includes:

[0117] S31. Acquire a plurality of brake pedal stroke data of the vehicle and a plurality of deceleration data corresponding to the brake pedal stroke data.

[0118] S32. Formulate a relationship table between the brake pedal travel data and the total target brake pressure according to the deceleration data.

[0119] S33. Obtain the total mass of the vehicle and the estimated driving slope of the vehicle.

[0120] S34. Perform a first-level correction on the total braking pressure according to the total mass, the estimated driving slope and the deceleration data of the vehicle and generate a first-level target braking pressure.

[0121] The first-level target brake pressure is calculated by formula (4):

[0122]

[0123] Among them, m est is the estimated total mass of the car, m is the total mass of the car under standard load, P tar_raw is the total braking pressure, α is the estimated driving slope, P tar_fix1 is the first-level target braking pressure, a is the deceleration data; where P tar_raw It is obtained by querying the relationship table between brake pedal travel data and total target brake pressure (ie, Table 3).

[0124] Specifically, since the total brake pressure in the above Table 3 is calculated based on theory and formulas, it may be different from the actual situation. Therefore, the total brake pressure needs to be corrected. According to the total mass of the vehicle determined in the above step S33, the estimated driving slope and the deceleration data of the vehicle, the total brake pressure calculated in the theory is corrected at the first level according to formula (4) and a first-level target brake pressure is generated.

[0125] S35. Determine the front axle brake pressure, rear axle brake pressure, and motor target braking torque of the vehicle according to the total target braking pressure.

[0126] Based on the above-mentioned embodiment of the invention, the embodiment of the invention further refines the total brake pressure after performing a primary correction and generating a primary target brake pressure according to the total mass of the vehicle, the estimated driving slope and the deceleration data of the vehicle. Figure 5 is a flow chart of another method for dynamically adjusting the braking force of an automobile provided by an embodiment of the present invention, with reference to Figure 5 The vehicle braking force dynamic adjustment method provided by the embodiment of the present invention also includes:

[0127] S41. Acquire a plurality of brake pedal stroke data of the vehicle and a plurality of deceleration data corresponding to the brake pedal stroke data.

[0128] S42. Formulate a relationship table between the brake pedal travel data and the total target brake pressure according to the deceleration data.

[0129] S43. Obtain the total mass of the vehicle and the estimated driving slope of the vehicle.

[0130] S44. Perform a first-level correction on the total braking pressure according to the total mass, the estimated driving slope and the deceleration data of the vehicle and generate a first-level target braking pressure.

[0131] S45. Obtain the actual braking deceleration of the vehicle during the detection process.

[0132] Specifically, the vehicle is tested and the actual braking deceleration during the test is obtained. The specific steps are as follows:

[0133] If the start detection condition is met at time t0, the vehicle speed value v(t0) is recorded, and the cumulative timing starts with a step size of Δt;

[0134] If the exit detection condition is met at time t1, the vehicle speed value v(t1) at this time is recorded, where t1 = ∑Δt.

[0135] The actual braking deceleration of the car is:

[0136]

[0137] S46. Perform a second-level correction on the first-level target braking pressure according to the relationship between the actual braking deceleration and the target braking deceleration, and generate a total target braking pressure.

[0138] Specifically, the first-level target braking pressure is corrected twice according to the relationship between the actual braking deceleration and the target braking deceleration calculated in the above step S45, and a total target braking pressure is generated. For example, when the actual braking deceleration is less than the target braking deceleration, a positive correction is performed; when the actual braking deceleration is greater than the target braking deceleration, a negative correction is performed. For example, the conditions for entering the detection are: (1) the brake pedal is depressed; (2) the accelerator pedal is released; (3) the brake pedal travel s remains stable and the fluctuation does not exceed ±Δs; (4) the feedback total braking pressure remains stable p and the fluctuation does not exceed ±Δ p, (5) the vehicle speed is greater than 0 km / h. When the vehicle meets conditions (1), (2), (3), (4) and (5) at the same time, the vehicle enters the detection process. The conditions for exiting the detection are: (1) the accelerator pedal is pressed, (2) the brake pedal is released, (3) the brake pedal travel s fluctuates by more than ±Δs, (4) the total brake pressure fluctuates by more than ±Δp, (5) the vehicle speed is 0 km / h, (6) the upper limit of the brake detection time is exceeded (the accumulated timing time of Δt exceeds the set value). When the vehicle meets any of the above conditions (1), (2), (3), (4), (5) and (6), the vehicle exits the detection process.

[0139] S47. Determine the front axle brake pressure, rear axle brake pressure, and motor target braking torque of the vehicle according to the total target braking pressure.

[0140] Based on the above-mentioned embodiment of the invention, the embodiment of the invention further refines the second-level correction of the first-level target braking pressure according to the relationship between the actual braking deceleration and the target braking deceleration and generates the total target braking pressure. Figure 6 is a flow chart of another method for dynamically adjusting the braking force of an automobile provided by an embodiment of the present invention, with reference to Figure 6 The vehicle braking force dynamic adjustment method provided by the embodiment of the present invention includes:

[0141] S51. Acquire a plurality of brake pedal stroke data of the vehicle and a plurality of deceleration data corresponding to the brake pedal stroke data.

[0142] S52. Formulate a relationship table between the brake pedal travel data and the total target brake pressure according to the deceleration data.

[0143] S53: Obtain the total mass of the vehicle and the estimated driving slope of the vehicle.

[0144] S54, performing a first-level correction on the total braking pressure according to the total mass, the estimated driving slope and the deceleration data of the vehicle and generating a first-level target braking pressure.

[0145] S55. Obtain the actual braking deceleration of the vehicle during the detection process.

[0146] S56. Compare the actual braking deceleration with the target braking deceleration; if the actual braking deceleration is less than the target braking deceleration, execute step S5601; if the actual braking deceleration is greater than the target braking deceleration, execute step S5602.

[0147] S5601. When the actual braking deceleration is smaller than the target braking deceleration for n consecutive times, the first-level target braking pressure is corrected in a positive direction.

[0148] Specifically, when the actual braking deceleration is less than the target braking deceleration for n consecutive times, the positive direction counter increases by 1. The positive direction counter is a variable in the program. The specific positive correction method is:

[0149] The forward correction is performed by equation (5) and equation (6):

[0150] N(k)=N(k-1)×F P (5)

[0151] Among them, N(k) is the current correction coefficient, N(k-1) is the previous correction coefficient, and F p is the positive step correction factor, F p >1;

[0152] p tar_fix2 =p tar_fix1 ×N(k) (6)

[0153] Among them, P tar_fix2 is the total target braking pressure, P tar_fix1 It is the first-level target brake pressure, and the forward counter is set to 0 at the same time.

[0154] S5602: When the actual braking deceleration is greater than the target braking deceleration for n consecutive times, the first-level target braking pressure is corrected negatively.

[0155] Specifically, when the actual braking deceleration is greater than the target braking deceleration for at least n consecutive times, the negative direction counter increases by 1. The negative direction counter is a variable in the program. The specific negative correction method is:

[0156] Negative correction is performed by formula (7) and formula (8):

[0157] N(k)=N(k-1)×F N (7)

[0158] Among them, N(k) is the current correction coefficient, N(k-1) is the previous correction coefficient, and F N is the negative step correction coefficient, 0 <F N <1;

[0159] ptar_fix2 =p tar_fix1 ×N(k) (8)

[0160] Among them, P tar_fix2 is the total target braking pressure, P tar_fix1 is the first-level target braking pressure, and the negative counter is set to 0; n is a positive integer greater than or equal to 2.

[0161] On the basis of the above-mentioned embodiment of the invention, the embodiment of the present invention further refines the determination of the front axle brake pressure, the rear axle brake pressure and the motor target brake torque of the automobile according to the total target brake pressure, and formulates the total target brake pressure, the front axle brake pressure and the rear axle brake pressure relationship table according to the theoretical ideal I curve of the automobile; the rear axle motor available brake equivalent pressure value is determined by formula (9);

[0162] p MotMax =C×T mot_brmax | (9)

[0163] Among them, P MotMax is the equivalent braking pressure value of the rear axle motor, T mot_brmax is the available braking torque of the rear axle motor, C is the torque-pressure conversion coefficient,

[0164] Among them, the automobile theoretical I curve is an idealized front and rear wheel brake force distribution curve, which describes the relationship curve that the front and rear wheel brake forces should satisfy in order to lock the front and rear wheels at the same time when braking on roads with various adhesion coefficients. Then, through the calibration method, it is adjusted according to the actual front and rear wheel locking limits under the condition of standard vehicle load to determine the front axle brake pressure P f_tar and rear axle brake pressure P rall_tar And draw Table 4.

[0165] Total target brake pressure 0 <![CDATA[P tar (k-1)]]> <![CDATA[P tar (k)]]> Front axle brake pressure 0 <![CDATA[P f_tar (k-1)]]> <![CDATA[P f_tar (k)]]> Rear axle brake pressure 0 <![CDATA[P rall_tar (k-1)]]> <![CDATA[P rall_tar (k)]]>

[0166] Table 4

[0167] When the rear axle motor available brake equivalent pressure value is greater than or equal to the rear axle brake pressure, the motor target braking torque is determined by formula (10):

[0168]

[0169] Among them, T Mot_Tar is the motor target braking torque, P rall_tar is the rear axle brake pressure, and the rear axle brake target pressure P r_tar = 0; or,

[0170] When the rear axle motor available brake equivalent pressure value is less than the rear axle brake pressure, the motor target braking torque is determined by formula (11):

[0171] T Mot_Tar =T mot_brmax (11)

[0172] The motor target braking torque is determined by formula (12):

[0173] p r_tar =p rall_tar -p MotMax (12)

[0174] Among them, P r_tar is the motor target braking torque.

[0175] The total target braking pressure is obtained by performing a secondary correction on the total target braking force, and the total target braking pressure is respectively distributed to the front axle brake pressure, rear axle brake pressure and motor target braking torque of the vehicle through formula (11) and formula (12).

[0176] According to the same inventive concept, Figure 7 is a block diagram of a dynamic adjustment device for automobile braking force provided by an embodiment of the present invention, with reference to Figure 7 The embodiment of the present invention provides a dynamic adjustment device for automobile braking force, the dynamic adjustment device is used to execute the dynamic adjustment method for automobile braking force in any of the above-mentioned embodiments of the invention, and the dynamic adjustment device includes:

[0177] The acquisition module 1 is used to acquire a plurality of brake pedal travel data of the vehicle and a plurality of deceleration data corresponding to the plurality of brake pedal travel data.

[0178] Tabulation module 2 is used to formulate a relationship table between brake pedal travel data and total target brake pressure according to deceleration data.

[0179] The correction module 3 is used to obtain the total mass of the vehicle and the estimated driving slope of the vehicle; correct the total braking pressure according to the total mass, the estimated driving slope and the deceleration data and generate the total target braking pressure.

[0180] The distribution module 4 is used to determine the front axle brake pressure, the rear axle brake pressure and the motor target braking torque of the vehicle according to the total target braking pressure.

[0181] A dynamic adjustment device for automobile braking force provided in an embodiment of the present invention can achieve the same technical effect as a dynamic adjustment method for automobile braking force provided in the above-mentioned embodiment of the invention, which will not be described in detail here.

[0182] According to the same inventive concept, an embodiment of the present invention provides a vehicle, comprising the dynamic adjustment device for automobile braking force in the above-mentioned embodiment of the invention.

[0183] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for dynamically adjusting the braking force of an automobile, characterized in that: include: Acquire a plurality of brake pedal stroke data of the vehicle and a plurality of deceleration data corresponding to the plurality of brake pedal stroke data; formulating a relationship table between brake pedal travel data and total target brake pressure according to the deceleration data; Obtaining the total mass of the vehicle and the estimated driving slope of the vehicle; Correcting the total braking pressure according to the total mass, the estimated driving slope and the deceleration data and generating a total target braking pressure; The front axle brake pressure, the rear axle brake pressure and the motor target braking torque of the vehicle are determined according to the total target braking pressure.

2. The method for dynamically adjusting the braking force of an automobile according to claim 1, characterized in that: A relationship table between the brake pedal travel data and the total target brake pressure is formulated according to the deceleration data, including: determining a relationship table between the brake pedal stroke data and the total target braking force according to the brake pedal stroke data and the deceleration data; The total target braking force is calculated by formula (1): F tar_raw (k)=|m×a tar (k)| (1) Among them, F tar_raw (k) is the total target braking force, m is the total mass of the vehicle under standard load, and a tar (k) is the deceleration of the vehicle.

3. The method for dynamically adjusting the braking force of an automobile according to claim 1, characterized in that: After determining the relationship table between the brake pedal stroke data and the total target braking force according to the brake pedal stroke data and the deceleration data, the method includes: formulating a relationship table between the brake pedal stroke data and the total target braking pressure according to the brake pedal stroke data and the total target braking force; The total target braking pressure is calculated by formula (2): F tar_raw =A×p (2) Among them, F tar_raw is the total target braking force, A is the braking effectiveness factor, and p is the total target braking pressure.

4. The method for dynamically adjusting the braking force of an automobile according to claim 1, characterized in that: Obtaining the total mass of the vehicle and the estimated driving slope of the vehicle, including: The total mass and the estimated driving slope are calculated by formula (3): Among them, T mot is the motor drive torque of the vehicle, i g is the speed ratio from the motor to the wheel end of the vehicle, η is the transmission efficiency, r is the tire radius, m is the total mass of the vehicle under standard load, g is the acceleration of gravity, f is the rolling resistance coefficient, α is the estimated driving slope, C d is the drag coefficient, A is the frontal area, v is the vehicle speed, δ is the rotational mass coefficient, and a is the acceleration.

5. The method for dynamically adjusting the braking force of an automobile according to claim 4, characterized in that: The method further comprises: modifying the total braking pressure according to the total mass, the estimated driving slope and the deceleration data and generating a total target braking pressure, comprising: Performing a primary correction on the total braking pressure according to the total mass, the estimated driving slope and the deceleration data of the vehicle and generating a primary target braking pressure; The first-level target brake pressure is calculated by formula (4): Among them, m est is the estimated total mass of the vehicle, m is the total mass of the vehicle under standard load, P tar_raw is the total braking pressure, α is the estimated driving slope, P tar_fix1 is the first-level target braking pressure, a is the deceleration data; wherein, P tar_raw Obtained by querying the relationship table.

6. The method for dynamically adjusting the braking force of an automobile according to claim 5, characterized in that: After the total brake pressure is corrected at the first level according to the total mass, the estimated driving slope and the deceleration data of the vehicle and the first level target brake pressure is generated, the method further includes: Obtaining the actual braking deceleration of the vehicle during the detection process; The primary target braking pressure is corrected at a second level according to the relationship between the actual braking deceleration and the target braking deceleration to generate the total target braking pressure.

7. The method for dynamically adjusting the braking force of an automobile according to claim 6, characterized in that: Performing a secondary correction on the primary target braking pressure according to the relationship between the actual braking deceleration and the target braking deceleration and generating the total target braking pressure includes: When the actual braking deceleration is smaller than the target braking deceleration for n consecutive times, the first-level target braking pressure is corrected in a positive direction; or, When the actual braking deceleration is greater than the target braking deceleration for n consecutive times, the first-level target braking pressure is negatively corrected; wherein the positive correction is performed by formula (5) and formula (6): N(k)=N(k-1)×F P (5) Among them, N(k) is the current correction coefficient, N(k-1) is the previous correction coefficient, and F p is the positive step correction factor, F p >1; p tar_fix2 =p tar_fix1 ×N(k) (6) Among them, P tar_fix2 is the total target braking pressure, P tar_fix1 is the first-level target brake pressure; The negative correction is performed by formula (7) and formula (8): N(k)=N(k-1)×F N (7) Among them, N(k) is the current correction coefficient, N(k-1) is the previous correction coefficient, and F N is the negative step correction coefficient, 0 <F N <1; p tar_fix2 =p tar_fix1 ×N(k) (8) Among them, P tar_fix2 is the total target braking pressure, P tar_fix1 is the first-level target braking pressure, and n is a positive integer greater than or equal to 2.

8. The method for dynamically adjusting the braking force of an automobile according to claim 1, characterized in that: The determining of the front axle brake pressure, the rear axle brake pressure and the motor target braking torque of the vehicle according to the total target braking pressure includes: According to the ideal I curve of automobile theory, a relationship table of total target brake pressure, front axle brake pressure, and rear axle brake pressure is formulated; the available brake equivalent pressure value of the rear axle motor is determined by formula (9); p MotMax =C×T mot_brmax | (9) Among them, P MotMax is the equivalent braking pressure value of the rear axle motor, T mot_brmax is the available braking torque of the rear axle motor, C is the torque-pressure conversion coefficient, When the available brake equivalent pressure value of the rear axle motor is greater than or equal to the rear axle brake pressure, the motor target braking torque is determined by formula (10): Among them, T Mot_Tar is the motor target braking torque, P rall_tar is the rear axle brake pressure, and the rear axle brake target pressure P r_tar = 0; or, When the available brake equivalent pressure value of the rear axle motor is less than the rear axle brake pressure, the motor target braking torque is determined by formula (11): T Mot_Tar =T mot_brmax (11) The motor target braking torque is determined by formula (12): p r_tar =p rall_tar -p MotMax (12) Among them, P r_tar is the target braking torque of the motor.

9. A dynamic adjustment device for automobile braking force, characterized in that: The dynamic adjustment device is used to perform the dynamic adjustment method of the vehicle braking force according to any one of claims 1 to 8, and the dynamic adjustment device comprises: An acquisition module, used for acquiring a plurality of brake pedal travel data of the vehicle and a plurality of deceleration data corresponding to the plurality of brake pedal travel data; a tabulation module, for formulating a relationship table between brake pedal travel data and total target brake pressure according to the deceleration data; A correction module, configured to obtain the total mass of the vehicle and the estimated driving slope of the vehicle; correct the total braking pressure according to the total mass, the estimated driving slope and the deceleration data and generate a total target braking pressure; The allocation module is used to determine the front axle brake pressure, the rear axle brake pressure and the motor target braking torque of the vehicle according to the total target braking pressure.

10. A vehicle, characterized in that: The invention comprises the dynamic adjustment device for the braking force of an automobile as described in claim 9.

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