A method and device for dynamically adjusting automobile braking force and a vehicle

Abstract

The present invention discloses a method, device, and vehicle for dynamically adjusting the braking force of an automobile. The method comprises: obtaining multiple brake pedal travel data and multiple deceleration data corresponding to the multiple brake pedal travel data; formulating a relationship table between the brake pedal travel data and the total target brake pressure based on the deceleration data; obtaining the total mass of the automobile and the estimated driving slope of the automobile; correcting the total brake pressure and generating a total target brake pressure based on the total mass, the estimated driving slope, and the deceleration data; and determining the front axle brake pressure, rear axle brake pressure, and motor target brake torque of the automobile based on the total target brake pressure. The method for dynamically adjusting the braking force of an automobile provided by the present invention can achieve dynamic adjustment of the vehicle's braking force under different loads and different slopes, meeting the driver's demand for consistent braking feel.

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 a critical system on a vehicle, playing a vital role in driving safety. Traditionally, braking force control is typically related to brake pedal travel, typically using a fixed proportional relationship. This means that the same braking force is generated for the same brake pedal travel.

[0003] Commercial vehicles have significant variations in overall mass due to varying amounts of cargo. Using traditional braking force control methods, even with the same brake pedal travel, the deceleration rate can vary significantly depending on the vehicle's mass, leading to poor braking feel and even accidents. Summary of the Invention

[0004] The dynamic adjustment method of the vehicle braking force provided by the present invention adjusts the total target braking pressure by obtaining comprehensive information such as the total mass of the vehicle, the estimated driving slope and deceleration data, thereby realizing dynamic adjustment of the vehicle's braking force under different loads and different slopes, and meeting the driver's requirements 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 stroke 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 to generate 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, formulating a relationship table between brake pedal travel data and total target brake pressure based on the deceleration data includes:

[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, a tar (k) is the deceleration of the car.

[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 includes:

[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 using formula (3):

[0023]

[0024] Among them, T mot is the motor driving torque of the car, 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 first-level correction on the total brake pressure according to the total mass, the estimated driving slope and the deceleration data of the vehicle and generating a first-level target brake 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 first-level correction on the total brake pressure according to the total mass, the estimated slope, and the deceleration data of the vehicle and generating a first-level target brake 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 secondary 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 to generate the total target braking pressure includes:

[0034] When the actual braking deceleration is less 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, F p is the forward step correction coefficient, 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, 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 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):

[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 device for dynamically adjusting the braking force of an automobile is provided, wherein the device is configured to perform the method for dynamically adjusting the braking force of an automobile according to any one of the first aspects of the present invention, and the device comprises:

[0058] an acquisition module, configured to 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;

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

[0060] a correction module, configured to obtain the total mass of the vehicle and the estimated driving slope of the vehicle; and correct the total braking pressure according to the total mass, the estimated driving slope and the deceleration data to generate a total target braking pressure;

[0061] A distribution 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 includes the dynamic adjustment device for automobile braking force 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 multiple brake pedal travel data and multiple deceleration data corresponding to the multiple brake pedal travel data; formulating a relationship table between the brake pedal travel data and the total target braking pressure based on 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 a total target braking pressure based on the total mass, the estimated driving slope, and the deceleration data; and determining the front axle brake pressure, rear axle brake pressure, and motor target braking torque of the automobile based on 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 achieving dynamic adjustment of the vehicle's braking force under different loads and different slopes, thereby meeting the driver's demand for consistent braking feel.

[0064] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily 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 This 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 This 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 This 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 This 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 This 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 This 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 solutions of the present invention, the technical solutions 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 embodiments described 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 making creative efforts should fall within the scope of protection of the present invention.

[0074] It should be noted that the terms "first", "second", etc. in the description 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 numbers 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 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 the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present invention can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved. This is not limited herein.

[0076] Figure 1 This 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 1The brake pedal signal and accelerator pedal signal are transmitted to the vehicle controller 18, which then sends them to the front axle electronic hydraulic brake controller 1 via a controller area network (CAN) signal. The front axle electronic hydraulic brake controller 1 analyzes the brake pedal displacement signal, determines the total required target braking force, and distributes the total required target braking force into front and rear axle target braking pressures. The rear axle target braking force is then transmitted to the rear axle electronic hydraulic brake controller 2 via a CAN signal. The front axle electronic hydraulic brake controller 1 controls the torque output of the front axle brake motor 3. The front axle brake motor 3 rotates and transmits power to the front axle brake reduction mechanism 4. The front axle brake reduction mechanism 4 increases the torque of the front axle brake motor 3 and converts the rotational motion into linear motion, pushing the piston in the front axle brake cylinder 5 to generate hydraulic pressure. This hydraulic pressure is transmitted to the left and right front wheel brakes 6 and 7 through hydraulic lines, respectively, actuating the left and right front axle brakes. The front axle 10 is connected to the left and right front wheels 16 and 17, generating braking force for the left and right front wheels 16 and 17. By controlling the output torque of the front axle brake motor 3, different braking forces can be achieved for the two front wheels. After receiving the rear axle target brake pressure from the front axle brake controller 1, the rear axle electronic hydraulic controller 2 uses a brake distribution algorithm to convert the target rear axle brake pressure into a braking torque for the drive motor 12 and the braking pressures for the left and right rear wheel brakes. The rear axle electronic hydraulic controller 2 controls the output braking torque of the control motor 12 via CAN signals. The rear axle electronic hydraulic controller 2 controls the torque output of the rear axle brake motor 19. This motor, through the rear axle reduction mechanism 20, pushes the pistons of the rear axle brake cylinder 21 to generate brake fluid pressure. This brake fluid pressure is transmitted through hydraulic lines to the left and right rear wheel brakes 8 and 9, generating braking forces for the left and right rear wheels 14 and 15. The differential 13 facilitates precise steering of the vehicle. The front axle brake cylinder 5 and the rear axle brake cylinder 21 are each equipped with a pressure sensor, which transmits the front and rear axle brake cylinder pressures to the front and rear axle electronic hydraulic brake controllers 1 and 2, respectively, 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 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. Figure 2 , an 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 and a plurality of deceleration data corresponding to the plurality of brake pedal stroke data of a vehicle.

[0079] Specifically, a vehicle is tested to obtain a plurality of brake pedal travel data and a plurality of deceleration data corresponding to the brake pedal travel data and tabulate them. Table 1 is a relationship table between the brake pedal travel and the deceleration. As shown in Table 1, the specific tabulation steps are as follows:

[0080] During the vehicle braking test, calibration is performed in combination with the driver's subjective comfort evaluation. 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, 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. Develop a relationship table between the brake pedal travel data and the total target brake pressure based on the deceleration data.

[0084] Specifically, according to the brake pedal travel data and deceleration data acquired in the above step S1 and 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 a 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] Based on the above-mentioned embodiment of the invention, the embodiment of the present invention further refines the relationship table between the brake pedal stroke data and the total target brake pressure according to the deceleration data. Figure 3 This is a flow chart of another method for dynamically adjusting the braking force of an automobile provided by an embodiment of the present invention. 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, a tar (k) is the deceleration of the car.

[0097] During the vehicle braking test, calibration was performed based on the driver's subjective comfort evaluation. The brake pedal travel displacement s(k) was set from 0 to the maximum brake mechanical travel, with a certain step size Δs, and the sampling points were divided into s(k) = k × Δs, where k is a positive integer greater than 0. Table 2 was plotted based on the above formula (1) and the brake pedal travel data. Table 2 shows the relationship between the brake pedal travel and the total target braking force.

[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. Develop a relationship table between the brake pedal stroke data and the total target braking pressure based on 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 , correcting the total braking pressure according to the total mass, the estimated driving slope, and the deceleration data to 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] Based on 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 embodiment of the present invention provides a method for dynamically adjusting the braking force of a vehicle, including:

[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 car, 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 formula (3), the motor drive torque is calculated in real time by the motor controller based on the motor current. The vehicle speed is calculated by transforming the motor speed through the speed ratio from the motor to the vehicle's wheel end and the tire radius. The vehicle acceleration is obtained by taking the speed difference and applying a first-order filter. The quantities to be estimated in formula (3) are the vehicle mass and the slope; 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 on this series of equations, the vehicle mass m and slope α can be estimated.

[0116] Based on the above-mentioned embodiment of the invention, the embodiment of the present invention further refines 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 This is a flow chart of another method for dynamically adjusting the braking force of an automobile provided by an embodiment of the present invention. Figure 4 The embodiment of the present invention provides a method for dynamically adjusting automobile braking, including:

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

[0118] S32. Develop a relationship table between the brake pedal travel data and the total target brake pressure based on 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 using 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 (i.e. Table 3).

[0124] Specifically, since the total brake pressure in Table 3 is calculated based on theory and formulas, it may differ from the actual situation. Therefore, the total brake pressure needs to be corrected. According to the total mass of the vehicle determined in 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) to generate the first level target brake pressure.

[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 present invention further refines the process of performing a primary correction on the total brake pressure and generating a primary target brake pressure based on the total mass of the vehicle, the estimated driving slope, and the deceleration data of the vehicle. Figure 5 This is a flow chart of another method for dynamically adjusting the braking force of an automobile provided by an embodiment of the present invention. Figure 5 The vehicle braking force dynamic adjustment method provided by the embodiment of the present invention further 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. Create a relationship table between the brake pedal travel data and the total target brake pressure based on 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 secondary correction on the primary 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 stroke s remains stable and the fluctuation does not exceed ±Δs, and (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 car meets conditions (1), (2), (3), (4) and (5) at the same time, the car enters the detection process. The conditions for exiting the detection are: (1) the accelerator pedal is depressed, (2) the brake pedal is released, (3) the brake pedal stroke 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 car meets any of the above conditions (1), (2), (3), (4), (5) and (6), the car 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 present invention further refines the second-level correction of the first-level target brake pressure according to the relationship between the actual braking deceleration and the target braking deceleration and generates the total target brake pressure. Figure 6 This is a flow chart of another method for dynamically adjusting the braking force of an automobile provided by an embodiment of the present invention. Figure 6 The embodiment of the present invention provides a method for dynamically adjusting the braking force of an automobile, including:

[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: Create a relationship table between the brake pedal travel data and the total target brake pressure based on the deceleration data.

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

[0144] S54: 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.

[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 less 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 equations (5) and (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, F p is the forward step correction coefficient, 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 The first-level target brake pressure is set, and the forward counter is set to 0.

[0154] S5602: When the actual braking deceleration is greater than the target braking deceleration for n consecutive times, a negative correction is made to the first-level target braking pressure.

[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, 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, rear axle brake pressure and motor target braking torque of the automobile according to the total target braking pressure, formulates the relationship table of the total target braking pressure, front axle brake pressure and rear axle brake pressure according to the theoretical ideal I curve of the automobile; determines the available braking equivalent pressure value of the rear axle motor 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 meet 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, the front axle brake pressure P is determined by adjusting the actual front and rear wheel locking limits under the condition of standard vehicle load. 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, 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 target braking torque of the motor.

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

[0176] According to the same inventive concept, Figure 7 This 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 An embodiment of the present invention provides a device for dynamically adjusting the braking force of an automobile. The device is configured to execute the method for dynamically adjusting the braking force of an automobile in any of the above-mentioned embodiments of the invention. The device comprises:

[0177] The acquisition module 1 is used to 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.

[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] 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 a 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] The dynamic adjustment device for automobile braking force provided by an embodiment of the present invention can achieve the same technical effect as the dynamic adjustment method for automobile braking force provided by the above-mentioned embodiment of the invention, and 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 embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection 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 stroke 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 gradient, and the deceleration data to generate a total target braking pressure; 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 The formulating a relationship table between the brake pedal stroke data and the total target brake pressure according to the deceleration data includes: 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; 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 step of 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 includes: performing a first-level correction on the total brake pressure according to the total mass, the estimated driving slope and the deceleration data of the vehicle and generating a first-level target brake pressure; Obtaining the actual braking deceleration of the vehicle during the detection process; Performing a secondary correction on the primary target braking pressure according to the relationship between the actual braking deceleration and the target braking deceleration to generate the total target braking pressure; The performing a secondary correction on the primary target braking pressure according to the relationship between the actual braking deceleration and the target braking deceleration to generate the total target braking pressure includes: When the actual braking deceleration is less 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.

2. The method for dynamically adjusting the braking force of an automobile according to claim 1, characterized in that: The total target braking force is calculated by formula (1): ； Among them, F tar_raw (k) is the total target braking force, m is the total mass of the vehicle under standard load, a tar (k) is the deceleration of the car.

3. The method for dynamically adjusting the braking force of an automobile according to claim 1, characterized in that: The total target braking pressure is calculated by formula (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 using formula (3): ； Among them, T mot is the motor driving torque of the car, 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 first-level target brake pressure is calculated by formula (4): ； 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; 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 1, characterized in that: in, The forward correction is performed by formula (5) and formula (6): （5）； Among them, N (k) is the current correction coefficient, N (k-1) is the previous correction coefficient, F p is the forward step correction coefficient, F p >1; （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): （7）； Among them, N (k) is the current correction coefficient, N (k-1) is the previous correction coefficient, F N is the negative step correction coefficient, 0 <F N <1; （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.

7. 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); （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): （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): （11）； The motor target braking torque is determined by formula (12): （12）； Among them, P r_tar is the target braking torque of the motor.

8. A dynamic adjustment device for automobile braking force, characterized in that: The dynamic adjustment device is used to perform the dynamic adjustment method for the vehicle braking force according to any one of claims 1 to 7, and the dynamic adjustment device includes: an acquisition module, configured to 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; a tabulation module, configured to formulate 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; and correct the total braking pressure according to the total mass, the estimated driving slope and the deceleration data to generate a total target braking pressure; A distribution 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.

9. A vehicle, characterized in that: The invention comprises the dynamic adjustment device for automobile braking force as described in claim 8.

Images