Vehicle drive structure, vehicle, braking force control method, device and controller

Abstract

The present invention discloses a vehicle driving structure, a vehicle, a braking force control method, a device and a controller, which can solve the problem that the adhesion coefficient utilization rate of the front and rear wheels cannot be maximized during the driving and braking process of the vehicle, resulting in low vehicle driving stability. The method part includes: determining the braking intensity and the total required braking force of the vehicle; determining the required braking force of the front axle and the required braking force of the rear axle according to the total required braking force; determining the maximum feedback braking force of the front drive motor and the rear drive motor; and controlling the vehicle braking force according to the braking intensity, the required braking force of the front axle, the required braking force of the rear axle, the maximum feedback braking force of the front drive motor and the maximum feedback braking force of the rear drive motor.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle braking control, and in particular to a vehicle driving structure, a vehicle, a braking force control method, a device and a controller. Background Art

[0002] Electric vehicles refer to vehicles that use onboard power as power, use motors to drive wheels, and meet the requirements of road traffic and safety regulations. The traditional four-wheel drive structure usually includes structures such as a controller, clutch and transmission, reducer, differential, drive motor and power battery. The drive form and the braking force of the vehicle are changed by the cooperation of components such as the drive motor, transmission, differential and controller. However, the above-mentioned traditional drive structure contains a transmission and a clutch, and the structure is relatively complex. The drive form of a single drive motor is relatively simple, generally in front drive mode or rear drive mode. In the composite control of braking force, the vehicle driving and braking process cannot maximize the utilization rate of the adhesion coefficient of the front and rear wheels, and the vehicle driving stability is low. Summary of the invention

[0003] The present invention provides a vehicle driving structure, a vehicle, a braking force control method, a device and a controller, which can solve the problem that the adhesion coefficient utilization rate of the front and rear wheels cannot be maximized during the driving and braking process of the vehicle, resulting in low vehicle driving stability.

[0004] In a first aspect, the present invention provides a vehicle drive structure, the vehicle drive structure comprising a controller, a front differential, a front main reducer, a front drive motor, a rear differential, a rear main reducer, a rear drive motor and a power battery;

[0005] The front differential is connected to the brake of the front wheel and the front main reducer respectively, and the front main reducer is connected to the front drive motor; the rear differential is connected to the brake of the rear wheel and the rear main reducer respectively, and the rear main reducer is connected to the rear drive motor;

[0006] The controller is connected to the front drive motor and the rear drive motor respectively, and the power battery is connected to the front drive motor and the rear drive motor.

[0007] Furthermore, the controller includes a vehicle controller and a brake controller, the vehicle controller is connected to the brake controller, the brake controller is respectively connected to the front drive motor and the rear drive motor, and the power battery is connected to the brake controller.

[0008] Furthermore, the vehicle drive structure also includes a power converter, and the power converter is respectively connected to the front drive motor, the rear drive motor, the power battery and the vehicle controller.

[0009] Furthermore, the vehicle drive structure also includes a hydraulic anti-lock braking system and a pressure control unit, wherein the pressure control unit is respectively connected to the hydraulic anti-lock braking system, the brake integrated controller and the braking device, and the hydraulic anti-lock braking system is respectively connected to the brakes of the front wheels and the rear wheels.

[0010] Furthermore, the vehicle driving structure includes multiple working modes, including a front-wheel drive mode, a rear-wheel drive mode and a four-wheel drive mode.

[0011] In a second aspect, the present invention provides a vehicle, which includes the vehicle drive structure as described in the first aspect.

[0012] In a third aspect, the present invention provides a braking force control method, which is applied to the vehicle according to the second aspect, and is executed by a vehicle controller, and includes:

[0013] Determine braking intensity and total required braking force;

[0014] Determine the front axle required braking force and the rear axle required braking force according to the total required braking force;

[0015] Determine the maximum feedback braking force of the front drive motor and the rear drive motor;

[0016] The vehicle braking force is controlled according to the braking intensity, the required braking force of the front axle, the required braking force of the rear axle, the maximum feedback braking force of the front drive motor and the maximum feedback braking force of the rear drive motor.

[0017] Furthermore, the vehicle braking force is controlled according to the braking intensity, the front axle required braking force, the rear axle required braking force, the maximum feedback braking force of the front drive motor and the maximum feedback braking force of the rear drive motor, including:

[0018] Determine the magnitude relationship between the braking intensity and the first preset value and the second preset value;

[0019] If the braking intensity is greater than the first preset value and less than the second preset value, the vehicle braking force is controlled according to the front axle required braking force, the rear axle required braking force, the maximum feedback braking force of the front drive motor, and the maximum feedback braking force of the rear drive motor;

[0020] If the braking intensity is greater than or equal to the second preset value, the motor braking is turned off and hydraulic braking is used.

[0021] Furthermore, the vehicle braking force is controlled according to the front axle required braking force, the rear axle required braking force, the maximum feedback braking force of the front drive motor and the maximum feedback braking force of the rear drive motor, including:

[0022] If the maximum feedback braking force of the front drive motor is greater than or equal to the required braking force of the front axle, the feedback braking force of the front drive motor is controlled to be the required braking force of the front axle, the feedback braking force of the rear drive motor is controlled to be the required braking force of the rear axle, and the front axle hydraulic braking force and the rear axle hydraulic braking force are controlled to be less than a preset braking value;

[0023] If the maximum feedback braking force of the front drive motor is less than the required front axle braking force, the front axle hydraulic braking force is determined according to the required front axle braking force and the maximum feedback braking force of the front drive motor, and the rear axle hydraulic braking force is determined according to the front axle hydraulic braking force and the front and rear axle hydraulic braking force distribution ratio, wherein the front and rear axle hydraulic braking force distribution ratio is determined within a preset braking intensity range with the minimum sum of squares of distance differences from line I as the goal;

[0024] If the sum of the maximum feedback braking force of the rear drive motor and the rear axle hydraulic braking force is greater than or equal to the rear axle required braking force, determining the rear drive motor feedback braking force according to the rear axle required braking force and the rear axle hydraulic braking force;

[0025] If the sum of the maximum feedback braking force of the rear drive motor and the rear axle hydraulic braking force is less than the required braking force of the rear axle, controlling the feedback braking force of the rear drive motor to be the maximum feedback braking force of the rear drive motor;

[0026] Determining the rear axle hydraulic braking force according to the rear axle required braking force and the maximum feedback braking force of the rear drive motor;

[0027] The front axle hydraulic braking force is determined according to the rear axle hydraulic braking force and the distribution ratio of the front and rear axle hydraulic braking forces.

[0028] Furthermore, the method further comprises:

[0029] If the front axle required braking force is greater than or equal to the front axle hydraulic braking force, and the front axle required braking force is less than or equal to the sum of the maximum feedback braking force of the front drive motor and the front axle hydraulic braking force, then the front drive motor feedback braking force is determined according to the front axle required braking force and the front axle hydraulic braking force;

[0030] If the required front axle braking force is less than the front axle hydraulic braking force, or the required front axle braking force is greater than the sum of the maximum feedback braking force of the front drive motor and the front axle hydraulic braking force, the front drive motor feedback braking force is controlled to be the maximum feedback braking force of the front drive motor, and the rear drive motor feedback braking force is controlled to be the maximum feedback braking force of the rear drive motor, and the front axle hydraulic braking force and the rear axle hydraulic braking force are controlled according to the front and rear axle hydraulic braking force distribution ratio, the front drive motor feedback braking force, the rear drive motor feedback braking force and the total required braking force.

[0031] Further, the controlling the front axle hydraulic braking force and the rear axle hydraulic braking force to be less than a preset braking value includes:

[0032] The front axle hydraulic braking force and the rear axle hydraulic braking force are controlled to be zero.

[0033] Further, the determining the front axle hydraulic braking force according to the front axle required braking force and the maximum feedback braking force of the front drive motor includes:

[0034] The front axle hydraulic braking force is determined as a difference between the front axle required braking force and the maximum feedback braking force of the front drive motor.

[0035] Further, determining the rear drive motor feedback braking force according to the rear axle required braking force and the rear axle hydraulic braking force includes:

[0036] The rear drive motor feedback braking force is determined as the difference between the rear axle required braking force and the rear axle hydraulic braking force.

[0037] Further, determining the rear axle hydraulic braking force according to the rear axle required braking force and the maximum feedback braking force of the rear drive motor includes:

[0038] The rear axle hydraulic braking force is determined as a difference between the rear axle required braking force and the maximum feedback braking force of the rear drive motor.

[0039] Further, the determining the front drive motor feedback braking force according to the front axle required braking force and the front axle hydraulic braking force includes:

[0040] The front drive motor feedback braking force is determined as a difference between the front axle required braking force and the front axle hydraulic braking force.

[0041] In a fourth aspect, the present invention provides a controller, comprising:

[0042] A first determination module, used to determine the braking intensity and the total required braking force;

[0043] A second determination module is used to determine the front axle required braking force and the rear axle required braking force according to the total required braking force;

[0044] The third determination module is used to determine the maximum feedback braking force of the front drive motor and the rear drive motor;

[0045] The control module is used to control the braking force according to the braking intensity, the required braking force of the front axle, the required braking force of the rear axle, the maximum feedback braking force of the front drive motor and the maximum feedback braking force of the rear drive motor.

[0046] In a fifth aspect, the present invention provides a controller comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the braking force control method of the vehicle drive structure as described in any one of claims 7 to 15 when executing the computer program.

[0047] In a sixth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the method in the third aspect described above are implemented, or the functions of the module in the fourth aspect described above are implemented.

[0048] It can be seen that in the above-mentioned vehicle drive structure, compared with the traditional drive structure, this solution does not require a clutch and a transmission, and mainly includes a front-drive motor, a rear-drive motor, and front and rear main reducers and differentials, which simplifies the traditional transmission system and has a relatively simple structure. In addition, since the front axle and the rear axle each have a drive motor, a reducer and a differential, the drive form of the vehicle drive structure can be driven or provide braking force in a front-drive form, or in a rear-drive form, or in a four-wheel drive form. The utilization rate of the adhesion coefficient of the front and rear wheels can be maximized during the driving and braking process, and the driving stability is effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0050] Figure 1 is a structural schematic diagram of a vehicle driving structure in an embodiment of the present invention;

[0051] Figure 2 is another structural schematic diagram of the vehicle driving structure in an embodiment of the present invention;

[0052] Figure 3 is another structural schematic diagram of the vehicle driving structure in an embodiment of the present invention;

[0053] Figure 4 is another structural schematic diagram of the vehicle driving structure in an embodiment of the present invention;

[0054] Figure 5 is a diagram showing a distribution curve relationship of a vehicle braking force in an embodiment of the present invention;

[0055] Figure 6 is a flow chart of a braking force control method according to an embodiment of the present invention;

[0056] Figure 7 yes Figure 6 A schematic flow chart of an implementation method of step S50;

[0057] Figure 8 yes Figure 7 A schematic flow chart of an implementation method of step S52;

[0058] Fig. 9 is a structural schematic diagram of a controller in an embodiment of the present invention;

[0059] Fig.10 Schematic diagram of a controller in an embodiment of the present invention. DETAILED DESCRIPTION

[0060] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are 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 are within the scope of protection of the present invention.

[0061] The present invention provides a vehicle drive structure, a braking force control method based on the vehicle drive structure and a related controller, which are described below respectively:

[0062] Example 1

[0063] like Figure 1 As shown, an embodiment of the present invention provides a vehicle drive structure, which includes a controller, a front differential, a front main reducer, a front drive motor, a rear differential, a rear main reducer, a rear drive motor and a power battery;

[0064] The front differential is connected to the brakes of the front wheels and the front main reducer respectively, and the front main reducer is connected to the front drive motor; the rear differential is connected to the brakes of the rear wheels and the rear main reducer respectively, and the rear main reducer is connected to the rear drive motor; the controller is connected to the front drive motor and the rear drive motor respectively, and the power battery is connected to the front drive motor and the rear drive motor. The power battery is used to provide working power for the front-drive motor and the rear-drive motor. Among them, each of the two front wheels is connected to a brake, and the brakes of the two front wheels are mechanically connected to the front differential respectively, and the front differential is mechanically connected to the front-drive motor through the front main reducer. Similarly, each of the two rear wheels is connected to a brake, and the brakes of the two rear wheels are mechanically connected to the rear differential respectively, and the rear differential is mechanically connected to the rear-drive motor through the rear reducer. The front-drive motor can be used to provide braking force or driving force to the front axle through the front differential through the front main reducer, and the rear-drive motor can be used to provide braking force or driving force to the rear axle through the rear differential through the rear main reducer. It can be seen that in In the above-mentioned vehicle drive structure, compared with the traditional drive structure, this solution does not require a clutch and a transmission, and mainly includes a front-drive motor, a rear-drive motor, and front and rear main reducers and differentials, which simplifies the traditional transmission system and has a relatively simple structure. In addition, since the front axle and the rear axle each have a drive motor, a reducer and a differential, the drive form of the vehicle drive structure can be driven or provide braking force in a front-drive form, or in a rear-drive form, or in a four-wheel drive form. During the driving and braking process, the utilization rate of the adhesion coefficient of the front and rear wheels can be maximized, effectively improving the driving stability.

[0065] like Figure 2 As shown, in one embodiment, the controller includes a vehicle controller and a brake controller, the vehicle controller is connected to the brake controller, and the brake controller is connected to the front drive motor and the rear drive motor respectively. In this embodiment, the controller is divided into a vehicle controller and a brake controller, wherein the brake controller is used to adjust and control the electric motor force of the front and rear axles, so that the adjustment ability of the electric motor force can be conveniently used to realize various braking functions, and the vehicle controller is used to control the action of the brake controller after making corresponding judgments according to driving disclosure and user instructions, thereby realizing various braking functions.

[0066] like Figure 3 As shown, in one embodiment, the vehicle drive structure further includes a power converter, and the power converter is respectively connected to the front drive motor, the rear drive motor, the power battery and the vehicle controller. In this embodiment, the functional converter is used to convert and recover the energy of the front drive motor and / or the rear drive motor during the braking process to feed it back to the power battery, so as to charge the power battery. Due to the use of two motors on the front and rear axles, the braking energy of the front and rear wheels can be recovered during the braking process, greatly improving the energy recovery efficiency.

[0067] like Figure 4 As shown, in one embodiment, the vehicle driving structure further includes a hydraulic anti-lock braking system (hydraulic ABS system) and a pressure control unit, wherein the pressure control unit is respectively connected to the hydraulic anti-lock braking system, the brake integrated controller and the brake device, and the hydraulic anti-lock braking system is respectively connected to the brakes of the front wheels and the rear wheels. The brake device is a device for receiving a braking force indication applied by the driver, such as a brake pedal, and the pressure control unit connected to the brake device can detect the corresponding pressure of the driver's pedal, thereby feeding back to the hydraulic ABS system, thereby applying hydraulic braking force to the brakes of the front wheels and / or the rear wheels.

[0068] In one embodiment, the vehicle drive structure includes multiple working modes, including front-wheel drive mode, rear-wheel drive mode and four-wheel drive mode. The vehicle controller is disclosed in different forms and the driver's needs. The driving form of the vehicle drive structure can be freely switched between the front-wheel drive mode, the rear-wheel drive mode and the four-wheel drive mode. The specific description is not expanded here. It should be noted that in addition to the above-mentioned modes, there may be other working modes, which are not limited in the embodiments of the present invention.

[0069] It should be noted that an embodiment of the present invention further provides a vehicle, which includes the vehicle drive structure mentioned above.

[0070] Example 2

[0071] It can be understood that a vehicle four-wheel drive structure with dual motors and a corresponding vehicle are proposed in Example 1. For a vehicle including the above-mentioned vehicle four-wheel drive structure, when braking, the braking force of the front and rear axles can be adjusted by the braking force of the motor, especially for electric vehicles that cannot perform hydraulic braking torque control on each wheel, which has a good regulating effect on the braking stability of the vehicle under straight-line conditions. In the embodiment of the present invention, only the braking force regulating effect of the front and rear motors is used to realize the braking force distribution based on the I line of the vehicle including the above-mentioned vehicle drive structure, wherein the I line refers to the braking force relationship curve that the front and rear wheel brakes should meet in order to lock the front and rear wheels at the same time when braking on roads with various adhesion coefficients.

[0072] It can be understood from automobile theory that when a car brakes, when the front and rear braking force distribution relationship curve deviates upward from line I, the rear wheels will lock and slip before the front wheels. At this time, the rear axle may skid, which is an unstable condition and the adhesion coefficient is also low. When the front and rear braking force distribution relationship curve deviates downward from line I, the front wheels will lock and slip first, and then the rear wheels will lock and slip, so that the steering ability is lost and the adhesion conditions are not fully utilized. Only when the front and rear braking force distribution relationship curve is distributed along line I or as close to line I as possible from the bottom, the front and rear wheels can reach the locking and slipping conditions at the same time, so as to maximize the stability during braking and make full use of the adhesion conditions.

[0073] like Figure 5 As shown, the present invention proposes that in the dual motor mode, the braking force distribution of the front and rear axles should be distributed according to the I line as much as possible. When the distribution of the front and rear driving forces cannot meet the I line distribution, in order to ensure the braking stability of the vehicle, it is necessary to ensure that the braking force distribution curve is below the I line and meets the total braking force demand and ECE regulations. The distribution strategy is as follows Figure 5 As shown. Among them, the Z line in the figure is the total braking force demand distribution line. The braking force of the front and rear axles must be guaranteed to be on the Z line to meet the total braking force demand. Point A is the intersection of the I line and the Z line. When it is located at point A, it means that it can meet both the total braking force demand and the I line braking force distribution; the β line is the front and rear axle hydraulic braking force distribution line, and point C is the intersection of the β line and the Z line. When pure hydraulic braking is performed, the braking force of the front and rear axles is distributed according to point C; point B is located on the Z line and between point A and point C. When the braking force is distributed according to point B, the braking stability of the vehicle is better than the pure hydraulic braking situation, but inferior to the I line distribution situation. In an embodiment of the present invention, a braking force control method for a vehicle drive structure is proposed. The core idea is to distribute the electric and hydraulic composite braking force of the front and rear axles so that the braking force is distributed according to point A as much as possible; when the distribution at point A cannot be met, the braking force is distributed according to point B; when the electric machine force is completely withdrawn, the braking force is distributed according to point C. The following is a detailed description:

[0074] like Figure 6 As shown, an embodiment of the present invention provides a braking force control method for a vehicle drive structure. Taking the energy control method applied to a vehicle controller as an example, the method includes the following steps:

[0075] S10: Determine the braking intensity.

[0076] S20: Determine the total required braking force.

[0077] S30: Determine the front axle required braking force and the rear axle required braking force according to the total required braking force.

[0078] Braking intensity z is an evaluation index of braking performance, which represents the ratio of the vehicle's braking deceleration to the acceleration due to gravity. The total required braking force can be calculated based on the brake master cylinder pressure.

[0079] In this embodiment, the front axle required braking force and the rear axle required braking force are distributed according to the line according to the total required braking force, that is:

[0080] F FI =Gz(b+zh g ) / L

[0081] F RI =Gz(a-zh g ) / L

[0082] F z =F FI +F RI

[0083] Among them, F RI The required braking force of the rear axle distributed according to the I line; F FI The required braking force of the front axle according to the I line distribution; F z is the total required braking force, G is the gravity parameter, h g is the distance from the center of mass of the vehicle to the ground, L is the distance between the front wheel and the rear wheel, a is the distance from the center of mass of the vehicle to the center line of the front axle, and b is the distance from the center of mass of the vehicle to the center line of the rear axle.

[0084] S40: Determine the maximum feedback braking force of the front drive motor and the rear drive motor.

[0085] The maximum feedback braking force of the front drive motor is related to the speed n of the front drive motor and is a function of the speed n. The maximum feedback braking force of the front drive motor can be expressed as max(F reg_F (n)): The maximum feedback braking force of the rear-drive motor is related to the speed n of the rear-drive motor and is a function of the speed n. The maximum feedback braking force of the rear-drive motor can be expressed as max(F reg_R (n)). Therefore, the maximum feedback braking force of the front drive motor and the maximum feedback braking force of the rear drive motor can be determined respectively according to the rotation speeds of the front drive motor and the rear drive motor.

[0086] S50: Controlling the braking force according to the braking intensity, the required braking force of the front axle, the required braking force of the rear axle, the maximum feedback braking force of the front drive motor and the maximum feedback braking force of the rear drive motor.

[0087] After determining the braking intensity, the required braking force of the front axle, the required braking force of the rear axle, the maximum regenerative braking force of the front drive motor, and the maximum regenerative braking force of the rear drive motor, the braking of the vehicle drive structure can be controlled according to the braking intensity, the required braking force of the front axle, the required braking force of the rear axle, the maximum regenerative braking force of the front drive motor, and the maximum regenerative braking force of the rear drive motor, so that during the process of electro-hydraulic and composite braking force distribution, it can be located at the required braking force distribution point.

[0088] It should be noted that the determination order of the above braking intensity and the total required braking force is not limited, the determination order of the required braking force of the front axle and the required braking force of the rear axle is not limited, the determination order of the maximum regenerative braking force of the front drive motor and the rear drive motor is not limited, and in addition, the execution order between steps S10 - S30 is not limited.

[0089] Among them, in one embodiment, as Figure 7 shown, in step S50, that is, controlling the braking of the vehicle drive structure according to the braking intensity, the required braking force of the front axle, the required braking force of the rear axle, the maximum regenerative braking force of the front drive motor, and the maximum regenerative braking force of the rear drive motor, specifically includes the following steps:

[0090] S51: Determine the magnitude relationship between the braking intensity and the first preset value and the second preset value. If the braking intensity is greater than the first preset value and less than the second preset value, then execute step S52; if the braking intensity is greater than or equal to the second preset value, then execute step S53.

[0091] In the embodiment of the present invention, the magnitude of the braking intensity z will be determined. Specifically, the magnitude relationship between the braking intensity and the first preset value and the second preset value is determined. Among them, the first preset value and the second preset value are preset values obtained in advance according to actual working condition experience. Exemplarily, the above first preset value can be 0, and the second preset value can be 0.7. If the braking intensity z is greater than 0 and less than 0.7, that is, if 0 < z < 0.7, then execute step S52; if the braking intensity z is greater than or equal to 0.7, that is, if z ≥ 0.7, then execute step S53.

[0092] It should be noted that the above first preset value and second preset value are only for exemplary illustration and do not limit the embodiments of the present invention.

[0093] S52: Control the vehicle braking force according to the required braking force of the front axle, the required braking force of the rear axle, the maximum regenerative braking force of the front drive motor, and the maximum regenerative braking force of the rear drive motor.

[0094] If the braking intensity is greater than the first preset value and less than the second preset value, the braking of the vehicle drive structure is controlled according to the required braking force of the front axle, the required braking force of the rear axle, the maximum feedback braking force of the front drive motor and the maximum feedback braking force of the rear drive motor.

[0095] Specifically, in one embodiment, Figure 8 As shown, in step S52, the braking of the vehicle drive structure is controlled according to the front axle required braking force, the rear axle required braking force, the maximum feedback braking force of the front drive motor and the maximum feedback braking force of the rear drive motor, specifically referring to the following braking force distribution control, which specifically includes the following steps:

[0096] S521: Determine the relationship between the maximum feedback braking force of the front drive motor and the required braking force of the front axle. If the maximum feedback braking force of the front drive motor is greater than or equal to the required braking force of the front axle, execute step S522; if the maximum feedback braking force of the front drive motor is less than the required braking force of the front axle, execute steps S523-S524.

[0097] That is, when the maximum feedback braking force max (F reg_F (n)) and the required braking force on the front axle F FI After that, the maximum feedback braking force max(F reg_F (n)) and the required braking force on the front axle F FI If max(F reg_F (n))≥F FI , then execute step S522; in another case, if max(F reg_F (n)) <F FI , then execute step S523.

[0098] S522: controlling the front drive motor feedback braking force to be the front axle required braking force, controlling the rear drive motor feedback braking force to be the rear axle required braking force, and controlling the front axle hydraulic braking force and the rear axle hydraulic braking force to be less than a preset braking value;

[0099] It can be understood that the actual braking force of the front and rear axles is composed of friction braking force and regenerative braking force, which are respectively:

[0100] F xb1 =F hy_F +F reg1

[0101] F xb2 =F hy_R +F reg2

[0102] Among them, F xb1is the actual total braking force of the front axle; F xb2 is the actual total braking force of the rear axle; F hy_F F is the front axle hydraulic braking force; hy_R is the rear axle hydraulic braking force; F reg1 Feedback braking force for the front axle motor; F reg2 Feedback braking force to the rear drive motor.

[0103] In the embodiment of the present invention, if max(F reg_F (n))≥F FI , indicating that the maximum regenerative braking force of the front drive motor can also meet the braking demand, so the front drive motor feedback braking force F is controlled reg1 The required braking force F of the front axle FI , control the rear drive motor feedback braking force F reg2 The required braking force F of the rear axle RI , and controls the front axle hydraulic braking force F hy_F and rear axle hydraulic brake force F hy_R Less than the preset braking value. For example, the front axle hydraulic braking force F hy_F and rear axle hydraulic brake force F hy_R is 0. That is, if max(F reg_F (n))≥F FI When:

[0104] F reg1 =F FI

[0105] F hy_F =0

[0106] F reg2 =F RI

[0107] F hy_R =0

[0108] It is worth noting that, since the braking force required of the rear wheels is less than that of the front wheels during braking, and the front and rear motor drive systems of the vehicle drive structure provided by the embodiment of the present invention are completely identical, the maximum regenerative braking force of the rear drive motor can also meet the braking demand. Therefore, at max(F reg_F (n))≥F FI When the rear drive motor feedback braking force F reg2 The required braking force F of the rear axle RI , and controls the rear axle hydraulic braking force F hy_R is 0.

[0109] S523: Determine the front axle hydraulic braking force according to the front axle required braking force and the maximum feedback braking force of the front drive motor, and determine the rear axle hydraulic braking force according to the front axle hydraulic braking force and the front and rear axle hydraulic braking force distribution ratio.

[0110] S524: Determine the relationship between the sum of the maximum feedback braking force of the rear-drive motor and the rear axle hydraulic braking force and the required braking force of the rear axle. If the sum of the maximum feedback braking force of the rear-drive motor and the rear axle hydraulic braking force is greater than or equal to the required braking force of the rear axle, execute step S525: If the sum of the maximum feedback braking force of the rear-drive motor and the rear axle hydraulic braking force is less than the required braking force of the rear axle, execute step S526.

[0111] and max(F reg_F (n))≥F FI The situation is different when max(F reg_F (n)) <F FI When the front axle braking force F is first applied according to the front axle braking force F FI The maximum feedback braking force max(F reg_F (n)) Determine the front axle hydraulic braking force F hy_F , and according to the front axle hydraulic braking force F hy_F The rear axle hydraulic braking force F is determined by the front and rear axle hydraulic braking force distribution ratio hy_R Finally, according to the maximum feedback braking force max(F reg_R (n)) and rear axle hydraulic braking force F hy_R The sum of the two, and the rear axle required braking force F RI The size relationship is based on two situations to control the braking force distribution, which are:

[0112] The first case: If the maximum feedback braking force max(F reg_R (n)) and rear axle hydraulic braking force F hy_R The sum of is greater than or equal to the required braking force F of the rear axle RI , that is: if max(F reg_R (n))+F hy_R ≥F RI , then execute step S525;

[0113] The second case: If the maximum feedback braking force max (F reg_R (n)) and the rear axle hydraulic braking force F hy_R The sum of is less than the required braking force F of the rear axle RI , that is: if max(F reg_R (n))+F hy_R <F RI, then execute step S526.

[0114] Specifically, in order to make the braking force distribution curve as close to the I line as possible, at this time, according to the front axle required braking force F FI The maximum feedback braking force max(F reg_F (n)) Determine the front axle hydraulic braking force F hy_F , specifically refers to determining the front axle hydraulic braking force F hy_F The required braking force F of the front axle FI The maximum feedback braking force max(F reg_F (n)), that is:

[0115] F hy_F =F FI -max(F reg1 (n))

[0116] Correspondingly, after determining the front axle hydraulic braking force F hy_F After that, the front axle hydraulic brake force F hy_F The rear axle hydraulic braking force F is determined by the front and rear axle hydraulic braking force distribution ratio hy_R , that is:

[0117] F hy_R =F hy_F (1-β b ) / β b

[0118] Among them, β b is the hydraulic braking force distribution ratio between the front and rear axles, which is obtained by optimizing the objective function of minimizing the sum of squares of distance differences from line I within a preset braking intensity range, such as a braking intensity range of 0.2-0.8, under the constraints of ECE regulations.

[0119] S525: determining the rear drive motor feedback braking force according to the rear axle required braking force and the rear axle hydraulic braking force;

[0120] This step S525 is the execution step corresponding to the first case above, that is, at this time, if max(F reg_F (n)) <F FI , and max(F reg_R (n))+F hy_R ≥F RI When , it means that the rear axle is also able to meet the braking force distributed by line I, then the braking force of the front and rear axles is distributed according to line I. At this time, according to the rear axle required braking force F RI With the rear axle hydraulic braking force F hy_R Determine the rear drive motor feedback braking force F reg2In one embodiment, according to the rear axle required braking force F RI With the rear axle hydraulic braking force F hy_R Determine the rear drive motor feedback braking force F reg2 , specifically refers to determining the rear drive motor feedback braking force F reg2 The required braking force F of the rear axle RI With the rear axle hydraulic braking force F hy_R The difference, that is:

[0121] F reg2 =F RI -F hy_R

[0122] S526: Control the feedback braking force of the rear drive motor to be the maximum feedback braking force of the rear drive motor, determine the rear axle hydraulic braking force according to the rear axle required braking force and the maximum feedback braking force of the rear drive motor, and determine the front axle hydraulic braking force according to the rear axle hydraulic braking force and the front and rear axle hydraulic braking force distribution ratio.

[0123] This step is the execution step corresponding to the second case above, that is, if max(F reg_F (n)) <F FI , and max(F reg_R (n))+F hy_R <F RI When the rear axle cannot meet the I-line distribution requirement, the braking force is extracted from the rear drive motor on the rear axle, and the rear drive motor is controlled to feedback the braking force F reg2 is the maximum feedback braking force max(F reg_R (n)) and according to the required braking force F of the rear axle RI The maximum feedback braking force max(F reg_R (n)) Determine the rear axle hydraulic braking force F hy_R , and according to the rear axle hydraulic braking force F hy_R The front axle hydraulic braking force F is controlled by the front axle hydraulic braking force distribution ratio hy_F .

[0124] Specifically, in one embodiment, according to the rear axle required braking force F RI The maximum feedback braking force max(F reg_R (n)) Determine the rear axle hydraulic braking force F hy_R Specifically, it refers to determining the rear axle hydraulic braking force F hy_R The required braking force F of the rear axle RI The maximum feedback braking force max(F reg_R The difference between (n)).

[0125] In summary, specifically, if max(F reg_F (n)) <F FI , and max(F reg_R (n))+F hy_R <F RI The braking force can be distributed as follows:

[0126] F reg2 =max(F reg_R (n))

[0127] F hy_R =F RI -max(F reg_R (n))

[0128] F hy_F =F hy_R β b / (1-β b )

[0129] Among them, β b is the hydraulic braking force distribution ratio between the front and rear axles, which is obtained by optimizing the objective function of minimizing the sum of squares of distance differences from line I within a preset braking intensity range, such as a braking intensity range of 0.2-0.8, under the constraints of ECE regulations.

[0130] According to the above method, considering that the rear wheel first distributes the braking force according to the I line, the rear axle hydraulic braking force F hy_R and front axle hydraulic brake force F hy_F .

[0131] It should be noted that the above process describes the conditions and process for extracting the feedback braking force of the rear drive motor under what circumstances. In one embodiment, the method further proposes a process for controlling the feedback braking force of the front drive motor. After step S526, specifically, the method further includes the following steps:

[0132] S527: If the front axle required braking force is greater than or equal to the front axle hydraulic braking force, and the front axle required braking force is less than or equal to the sum of the maximum feedback braking force of the front drive motor and the front axle hydraulic braking force, determining the front drive motor feedback braking force according to the front axle required braking force and the front axle hydraulic braking force;

[0133] In the embodiment of the present invention, after determining the required braking force F of the front axle FI and front axle hydraulic brake force F hy_F After that, the front drive motor feedback braking force is further controlled to first determine the front axle required braking force F FI , front axle hydraulic braking force F hy_Fand the maximum feedback braking force of the front drive motor max(F reg_F (n)) between them, specifically, if the front axle requires braking force F FI Greater than or equal to the front axle hydraulic braking force F hy_F , and the front axle requires braking force F FI Less than or equal to the maximum feedback braking force max(F reg_F (n)) and the front axle hydraulic braking force F hy_F The sum of the two, at this time, indicates that the front axle can also meet the I-line braking force distribution, then the braking force of the front and rear axles is still distributed according to the I-line braking force distribution, that is, if F FI ≥F hy_F And max(F reg_F (n))+F hy_F ≥F FI , then according to the front axle required braking force F FI With the front axle hydraulic braking force F hy_F Determine the front drive motor feedback braking force F reg1 .

[0134] In one embodiment, according to the front axle required braking force F FI With the front axle hydraulic braking force F hy_F Determine the front drive motor feedback braking force F reg1 , specifically refers to determining the front drive motor feedback braking force F reg1 The required braking force F of the front axle FI With the front axle hydraulic braking force F hy_F The difference, that is:

[0135] F reg1 =F FI -F hy_F

[0136] S528: If the required front axle braking force is less than the front axle hydraulic braking force, or the required front axle braking force is greater than the sum of the maximum feedback braking force of the front drive motor and the front axle hydraulic braking force, the front drive motor feedback braking force is controlled to be the maximum feedback braking force of the front drive motor, and the rear drive motor feedback braking force is controlled to be the maximum feedback braking force of the rear drive motor, and the front axle hydraulic braking force and the rear axle hydraulic braking force are controlled according to the front and rear axle hydraulic braking force distribution lines, the front drive motor feedback braking force, the rear drive motor feedback braking force and the total required braking force.

[0137] That is: if F FI <F hy_F , or max(F reg_F (n))+F hy_F <F FIAt this time, the front and rear axle braking force distribution still cannot meet the I-line braking force distribution requirements, so the front and rear axle braking force distribution points move downward along the Z line, and the front and rear wheel braking force distribution method is as follows: Control the front drive motor to feedback the braking force F reg1 is the maximum feedback braking force max (F reg_F (n)), controlling the feedback braking force F of the rear drive motor reg2 is the maximum feedback braking force max (F reg_R (n)), and according to the front and rear axle hydraulic braking force distribution ratio line, the front drive motor feedback braking force F reg1 , the rear drive motor feedback braking force F reg2 and the total required braking force F z Control the front axle hydraulic braking force F hy_F and the rear axle hydraulic braking force F hy_R .

[0138] Specifically, the front and rear wheel braking force distribution is calculated according to the following formula:

[0139]

[0140] S53: Turn off the motor brake and use hydraulic brake.

[0141] In this step, if the braking intensity is greater than or equal to the second preset value, for example, if the braking intensity z is greater than or equal to 0.7, that is, if z≥0.7, the motor braking is turned off and hydraulic braking is used. At this time, hydraulic braking is fully used and the regenerative braking function is turned off to ensure braking capacity.

[0142] It should be understood that the order of execution of the steps in the above embodiment does not necessarily mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0143] In one embodiment, a controller is provided, which corresponds one-to-one to the vehicle controller in the braking force control method in the above embodiment. Fig. 9 As shown, the controller includes a first determination module, a second determination module, a third determination module and a control module. Each functional module is described in detail as follows:

[0144] A first determination module, used to determine the braking intensity and the total required braking force;

[0145] A second determination module is used to determine the front axle required braking force and the rear axle required braking force according to the total required braking force;

[0146] The third determination module is used to determine the maximum feedback braking force of the front drive motor and the rear drive motor;

[0147] The control module is used to control the vehicle braking force according to the braking intensity, the required braking force of the front axle, the required braking force of the rear axle, the maximum feedback braking force of the front drive motor and the maximum feedback braking force of the rear drive motor.

[0148] For the specific definition of the controller, please refer to the definition of the braking force control method above, which will not be repeated here. The various modules of the above controller can be implemented in whole or in part by software, hardware and their combination. The above modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0149] In one embodiment, a controller is provided. The computer device may be the vehicle controller in the aforementioned method embodiment, and its internal structure diagram may be as shown in FIG. Fig.10 As shown. The controller includes a processor and a memory connected via a system bus. The processor of the controller is used to provide computing and control capabilities. The memory of the controller includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The network interface of the computer device is used to communicate with external systems and components via a network connection. When the computer program is executed by the processor, a braking force control method is implemented.

[0150] In one embodiment, a controller is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the following steps when executing the computer program:

[0151] Determine braking intensity and total required braking force;

[0152] Determine the front axle required braking force and the rear axle required braking force according to the total required braking force;

[0153] Determine the maximum feedback braking force of the front drive motor and the rear drive motor;

[0154] The vehicle braking force is controlled according to the braking intensity, the required braking force of the front axle, the required braking force of the rear axle, the maximum feedback braking force of the front drive motor and the maximum feedback braking force of the rear drive motor.

[0155] In one embodiment, a computer readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented:

[0156] Determine braking intensity and total required braking force;

[0157] Determine the front axle required braking force and the rear axle required braking force according to the total required braking force;

[0158] Determine the maximum feedback braking force of the front drive motor and the rear drive motor;

[0159] The vehicle braking force is controlled according to the braking intensity, the required braking force of the front axle, the required braking force of the rear axle, the maximum feedback braking force of the front drive motor and the maximum feedback braking force of the rear drive motor.

[0160] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0161] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0162] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A braking force control method, characterized in that: The braking force control method is executed by a vehicle controller, and the method includes: Determine braking intensity and total required braking force; Determine the front axle required braking force and the rear axle required braking force according to the total required braking force; Determine the maximum feedback braking force of the front drive motor and the rear drive motor; The vehicle braking force is controlled according to the braking intensity, the front axle required braking force, the rear axle required braking force, the maximum feedback braking force of the front drive motor and the maximum feedback braking force of the rear drive motor; including: Determine the magnitude relationship between the braking intensity and the first preset value and the second preset value; If the braking intensity is greater than the first preset value and less than the second preset value, the vehicle braking force is controlled according to the front axle required braking force, the rear axle required braking force, the maximum feedback braking force of the front drive motor, and the maximum feedback braking force of the rear drive motor; If the braking intensity is greater than or equal to the second preset value, the motor braking is turned off and hydraulic braking is used; If the maximum feedback braking force of the front drive motor is greater than or equal to the required braking force of the front axle, the feedback braking force of the front drive motor is controlled to be the required braking force of the front axle, the feedback braking force of the rear drive motor is controlled to be the required braking force of the rear axle, and the front axle hydraulic braking force and the rear axle hydraulic braking force are controlled to be less than a preset braking value; If the maximum feedback braking force of the front drive motor is less than the required front axle braking force, the front axle hydraulic braking force is determined according to the required front axle braking force and the maximum feedback braking force of the front drive motor, and the rear axle hydraulic braking force is determined according to the front axle hydraulic braking force and the front and rear axle hydraulic braking force distribution ratio, wherein the front and rear axle hydraulic braking force distribution ratio is determined within a preset braking intensity range with the minimum sum of squares of distance differences from line I as the goal; If the sum of the maximum feedback braking force of the rear drive motor and the rear axle hydraulic braking force is greater than or equal to the rear axle required braking force, determining the rear drive motor feedback braking force according to the rear axle required braking force and the rear axle hydraulic braking force; If the sum of the maximum feedback braking force of the rear drive motor and the rear axle hydraulic braking force is less than the required braking force of the rear axle, controlling the feedback braking force of the rear drive motor to be the maximum feedback braking force of the rear drive motor; Determining the rear axle hydraulic braking force according to the rear axle required braking force and the maximum feedback braking force of the rear drive motor; Determining the front axle hydraulic braking force according to the rear axle hydraulic braking force and the front and rear axle hydraulic braking force distribution ratio; If the front axle required braking force is greater than or equal to the front axle hydraulic braking force, and the front axle required braking force is less than or equal to the sum of the maximum feedback braking force of the front drive motor and the front axle hydraulic braking force, then the front drive motor feedback braking force is determined according to the front axle required braking force and the front axle hydraulic braking force; If the required front axle braking force is less than the front axle hydraulic braking force, or the required front axle braking force is greater than the sum of the maximum feedback braking force of the front drive motor and the front axle hydraulic braking force, the front drive motor feedback braking force is controlled to be the maximum feedback braking force of the front drive motor, and the rear drive motor feedback braking force is controlled to be the maximum feedback braking force of the rear drive motor, and the front axle hydraulic braking force and the rear axle hydraulic braking force are controlled according to the front and rear axle hydraulic braking force distribution ratio, the front drive motor feedback braking force, the rear drive motor feedback braking force and the total required braking force.

2. The braking force control method according to claim 1, characterized in that: The controlling the front axle hydraulic braking force and the rear axle hydraulic braking force to be less than a preset braking value comprises: The front axle hydraulic braking force and the rear axle hydraulic braking force are controlled to be zero.

3. The braking force control method according to claim 1, characterized in that: The determining the front axle hydraulic braking force according to the front axle required braking force and the maximum feedback braking force of the front drive motor includes: The front axle hydraulic braking force is determined as a difference between the front axle required braking force and the maximum feedback braking force of the front drive motor.

4. The braking force control method according to claim 1, characterized in that: The determining the rear drive motor feedback braking force according to the rear axle required braking force and the rear axle hydraulic braking force includes: The rear drive motor feedback braking force is determined as the difference between the rear axle required braking force and the rear axle hydraulic braking force.

5. The braking force control method according to claim 1, characterized in that: The determining the rear axle hydraulic braking force according to the rear axle required braking force and the maximum feedback braking force of the rear drive motor includes: The rear axle hydraulic braking force is determined as a difference between the rear axle required braking force and the maximum feedback braking force of the rear drive motor.

6. The braking force control method according to claim 1, characterized in that: The determining the front drive motor feedback braking force according to the front axle required braking force and the front axle hydraulic braking force includes: The front drive motor feedback braking force is determined as a difference between the front axle required braking force and the front axle hydraulic braking force.

7. A controller, suitable for the braking force control method as described in any one of claims 1 to 6, characterized in that: include: A first determination module, used to determine the braking intensity and the total required braking force; A second determination module is used to determine the front axle required braking force and the rear axle required braking force according to the total required braking force; The third determination module is used to determine the maximum feedback braking force of the front drive motor and the rear drive motor; The control module is used to control the vehicle braking force according to the braking intensity, the required braking force of the front axle, the required braking force of the rear axle, the maximum feedback braking force of the front drive motor and the maximum feedback braking force of the rear drive motor.

8. A controller comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the braking force control method according to any one of claims 1 to 6 are implemented.

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