Vehicle braking method and device

Abstract

The invention provides a vehicle braking method and device. According to the technical scheme, a hydraulic device in the vehicle is controlled to provide first target hydraulic pressure for a front axle and a rear axle, and a motor device in the vehicle is controlled to provide first electric braking force for the front axle and provide second electric braking force for the rear axle; wherein the sum of the first hydraulic braking force generated by the first target hydraulic pressure on the front axle, the second hydraulic braking force generated by the first target hydraulic pressure on the rear axle, the first electric braking force and the second electric braking force is equal to the total braking force needed for braking the vehicle. A ratio of a first sum of the first hydraulic braking force and the first electric braking force to a second sum of the second hydraulic braking force and the second electric braking force is equal to a ratio of a first vertical load of a front axle of the vehicle to a second vertical load of a rear axle of the vehicle. According to the technical scheme provided by the invention, the stability of the vehicle during braking can be improved.

Description

Vehicle braking method and device Technical Field

[0001] The present application relates to the field of automotive technology, and in particular to a vehicle braking method and device. Background Art

[0002] Vehicle braking refers to forcibly slowing down or even stopping a moving vehicle according to the requirements of the driver or controller. Among them, hydraulic braking is a method of vehicle braking.

[0003] Currently, when a vehicle brakes hydraulically, the braking process is as follows: after the driver steps on the brake pedal, the total braking force required to brake the vehicle is determined. Then, based on the friction coefficient of the vehicle's front axle and the friction coefficient of the rear axle, the hydraulic pressure required to provide the total braking force through the vehicle's front and rear axles is determined, and the hydraulic pressure is provided to the vehicle's front and rear axles for braking.

[0004] However, in the above-mentioned method of achieving braking through hydraulic pressure, since the ratio of the front axle braking force to the rear axle braking force of the vehicle is a fixed value, the vehicle may become unstable during braking.

[0005] Summary of the Invention

[0006] The present application provides a vehicle braking method and device, which helps to avoid possible instability problems of the vehicle during braking.

[0007] In a first aspect, the present application provides a vehicle braking method, comprising: obtaining a total braking force, wherein the total braking force is the braking force required for the vehicle to achieve braking; controlling a hydraulic device in the vehicle to provide a first target hydraulic pressure for the front axle and the rear axle according to the total braking force, and controlling a motor device in the vehicle to provide a first electric braking force for the front axle and a second electric braking force for the rear axle; wherein the sum of the first hydraulic braking force generated on the front axle by the first target hydraulic pressure, the second hydraulic braking force generated on the rear axle by the first target hydraulic pressure, the first electric braking force, and the second electric braking force is equal to the total braking force, and the ratio of the first sum of the first hydraulic braking force and the first electric braking force to the second sum of the second hydraulic braking force and the second electric braking force is equal to the ratio of the first vertical load of the front axle of the vehicle to the second vertical load of the rear axle of the vehicle.

[0008] In the vehicle braking method provided in the present application, after the total braking force required for braking the vehicle is obtained, in addition to using a hydraulic device to provide a first target hydraulic pressure to provide braking force to the front axle and rear axle, a motor device is also used to provide braking force to the front axle and rear axle respectively.

[0009] That is to say, in this embodiment, the braking force provided to the front axle is the sum of the braking force provided to the front axle by the first target hydraulic pressure and the braking force provided to the front axle by the motor device, and the braking force provided to the rear axle is the sum of the braking force provided to the rear axle by the first target hydraulic pressure and the braking force provided to the rear axle by the motor device.

[0010] In addition, since in this embodiment, the ratio of the braking force provided to the front axle to the braking force provided to the rear axle is the same as the ratio of the first vertical load of the front axle of the vehicle to the second vertical load of the rear axle of the vehicle, the braking method based on this embodiment helps to determine the front axle braking force and the rear axle braking force located on the I curve, thereby helping to avoid instability during vehicle braking, that is, helping to improve the stability of the vehicle during braking.

[0011] In combination with the first aspect, in one possible implementation, the first target hydraulic pressure is the minimum hydraulic pressure between the first hydraulic pressure and the second hydraulic pressure, the first hydraulic pressure is the hydraulic pressure that the hydraulic device should provide when the front axle generates a first braking force, the second hydraulic pressure is the hydraulic pressure that the hydraulic device should provide when the rear axle generates a second braking force, the first braking force and the second braking force are the braking forces that should be allocated to the front axle and the rear axle respectively when the total braking force is allocated to the front axle and the rear axle according to the first vertical load and the second vertical load; and the electric braking force provided by the motor device to the first axle of the front axle and the rear axle is zero, and the first axle is the axle corresponding to the minimum hydraulic pressure.

[0012] It is understandable that because the minimum hydraulic pressure of the first and second hydraulic pressures can meet the braking force requirement of the axle (also referred to as the first axle) corresponding to the minimum of the first and second braking forces among the front and rear axles, using the minimum hydraulic pressure as the hydraulic pressure when the hydraulic device provides braking force eliminates the need for the electric motor device to provide additional braking force for the first axle, i.e., the electric braking force provided by the electric motor device to the first axle is zero. In other words, in this implementation, the electric braking force can be provided to another axle (also referred to as the second axle) solely by the electric motor device, such that the ratio of the total braking force (i.e., the electric braking force and the hydraulic braking force) generated on the second axle to the braking force generated on the first axle by the minimum hydraulic pressure satisfies the ratio of the vertical load on the second axle to the vertical load on the first axle.

[0013] In this embodiment, since the motor is only required to provide electric braking force for one axle, the braking stability of the vehicle can be improved in a relatively simple manner.

[0014] In combination with the first aspect, in a possible implementation, the method further includes: determining the first braking force that should be allocated to the front axle and the second braking force that should be allocated to the rear axle when the total braking force is allocated to the front axle and the rear axle according to the first vertical load and the second vertical load; determining the first hydraulic pressure that the hydraulic device should provide when the front axle generates the first braking force; determining the second hydraulic pressure that the hydraulic device should provide when the rear axle generates the second braking force; determining the minimum hydraulic pressure between the first hydraulic pressure and the second hydraulic pressure as the first target hydraulic pressure; determining the hydraulic braking force generated by the second axle of the front axle and the rear axle when the hydraulic device provides the first target hydraulic pressure to the second axle; and determining the difference between the braking force that should be allocated to the second axle in the total braking force and the hydraulic braking force generated by the second axle as the target electric braking force that the motor device should provide for the second axle.

[0015] Optionally, in the present application, the hydraulic device in the vehicle is controlled to provide a first target hydraulic pressure for the front axle and the rear axle, and the motor device in the vehicle is controlled to provide a first electric braking force for the front axle and a second electric braking force for the rear axle, including: if the maximum electric braking force that the motor device can provide for the second axle is greater than or equal to the target electric braking force, then the hydraulic device in the vehicle is controlled to provide the first target hydraulic pressure for the front axle and the rear axle, and the motor device in the vehicle is controlled to provide the target electric braking force for the second axle.

[0016] In this implementation, after the minimum hydraulic pressure between the first hydraulic pressure and the second hydraulic pressure is determined as the first target hydraulic pressure, the motor device is used to compensate the target braking force for the second shaft as the difference between the braking force that should be allocated to the second shaft and the hydraulic braking force generated by the minimum hydraulic pressure for the second shaft, thereby ensuring that the total braking force remains unchanged when the vehicle is braked, and further ensuring that the vehicle can brake as required.

[0017] In combination with the first aspect, in one possible implementation, if the maximum electric braking force that the motor device can provide to the second shaft is less than the target electric braking force, the method also includes: determining a second target hydraulic pressure, the third sum of the third hydraulic braking force generated by the second target hydraulic pressure on the front axle and the fourth hydraulic braking force generated by the second target hydraulic pressure on the rear axle is equal to the difference between the total braking force and the maximum electric braking force; controlling the hydraulic device in the vehicle to provide the second target hydraulic pressure to the front axle and the rear axle, and controlling the motor device in the vehicle to provide the maximum electric braking force to the second shaft.

[0018] It should be understood that there may be situations where the maximum braking force that the motor assembly can provide for the second shaft is less than the braking force that the motor assembly needs to compensate for. In this embodiment, when the maximum braking force that the motor assembly can provide for the second shaft is less than the braking force that the motor assembly needs to compensate for, the motor assembly is controlled to provide the maximum braking force for the second shaft. The remaining braking force (the difference between the total braking force and the maximum braking force provided for the second shaft) is then compensated for through hydraulic braking to ensure that the total braking force remains unchanged, thereby achieving vehicle braking.

[0019] In combination with the first aspect, in one possible implementation, the hydraulic device in the vehicle is controlled to provide a first target hydraulic pressure for the front axle and the rear axle according to the total braking force, and the motor device in the vehicle is controlled to provide a first electric braking force for the front axle and a second electric braking force for the rear axle, including: when preset conditions are met, the hydraulic device in the vehicle is controlled to provide a first target hydraulic pressure for the front axle and the rear axle according to the total braking force, and the motor device in the vehicle is controlled to provide a first electric braking force for the front axle and a second electric braking force for the rear axle, the preset conditions including: the rate of change of the brake pedal in the vehicle is greater than a preset first threshold, the opening of the brake pedal is greater than a preset second threshold, and the slip rate of the vehicle is greater than a preset third threshold.

[0020] It should be understood that a rate of change of the vehicle's brake pedal greater than a preset first threshold, or a brake pedal opening greater than a preset second threshold, or a vehicle slip ratio greater than a preset third threshold, may indicate a stronger need for braking, and further, may reflect a greater degree of emergency braking, thereby increasing the need to ensure vehicle stability during braking. Therefore, in this embodiment, as long as the rate of change of the vehicle's brake pedal greater than the preset first threshold, or the brake pedal opening greater than the preset second threshold, or the vehicle slip ratio greater than the preset third threshold, the braking method described in the first aspect of this application is executed, thereby helping to prevent possible vehicle instability during braking.

[0021] In combination with the first aspect, in one possible implementation, controlling a hydraulic device in a vehicle to provide a first target hydraulic pressure for the front and rear axles according to the total braking force, and controlling a motor device in the vehicle to provide a first electric braking force for the front axle and a second electric braking force for the rear axle, includes: obtaining mode setting information in the vehicle, the mode setting information including first mode information and / or second mode information, the first mode information indicating that when the total braking force remains unchanged, the ratio of the braking force of the front axle to the braking force of the rear axle is equal to the ratio of the first vertical load to the second vertical load, and the second mode information indicating that when the total braking force remains unchanged, the motor device provides a maximum electric braking force for the rear axle; when the mode setting information is the first mode information and the vehicle does not meet a preset condition, controlling the hydraulic device in the vehicle to provide the first target hydraulic pressure for the front and rear axles according to the total braking force, and controlling the motor device in the vehicle to provide the first electric braking force for the front axle and the second electric braking force for the rear axle, the preset condition including any one or more of the following conditions: a rate of change of a brake pedal in the vehicle is greater than a preset first threshold, a brake pedal opening is greater than a preset second threshold, and a vehicle slip ratio is greater than a preset third threshold.

[0022] In this implementation, the braking method described in the first aspect of the present application can be triggered by the mode setting information in the vehicle. It can be understood that in this implementation, the driver's needs can be met, thereby improving the driver's experience.

[0023] In combination with the first aspect, in a possible implementation, when the mode setting information is the second mode information, the method also includes: determining the maximum electric braking force that the motor device can provide to the rear axle; determining a third target hydraulic pressure, the fourth sum of the fifth hydraulic braking force generated by the third target hydraulic pressure on the front axle and the sixth hydraulic braking force generated by the third target hydraulic pressure on the rear axle is equal to the difference between the total braking force and the maximum electric braking force that can be provided to the rear axle; controlling the hydraulic device in the vehicle to provide the third target hydraulic pressure to the front and rear axles, and providing the maximum electric braking force to the rear axle through the motor device.

[0024] In this implementation, the driver's comfort during braking can be improved by enabling the motor device to provide the maximum electric braking force to the rear axle and compensating the remaining braking force through hydraulic pressure.

[0025] In a second aspect, the present application provides a vehicle braking device, which may include various modules for implementing the braking method in various implementations of the first aspect. Optionally, each module may be implemented in hardware and / or software.

[0026] For example, the braking device may include: an acquisition module for acquiring a total braking force, which is the braking force required for the vehicle to achieve braking; a control module for controlling a hydraulic device in the vehicle to provide a first target hydraulic pressure to the front axle and the rear axle according to the total braking force, and controlling a motor device in the vehicle to provide a first electric braking force to the front axle and a second electric braking force to the rear axle; wherein the sum of the first hydraulic braking force generated by the first target hydraulic pressure on the front axle, the second hydraulic braking force generated by the first target hydraulic pressure on the rear axle, the first electric braking force and the second electric braking force is equal to the total braking force, and the ratio of the first sum of the first hydraulic braking force and the first electric braking force to the second sum of the second hydraulic braking force and the second electric braking force is equal to the ratio of the first vertical load of the front axle of the vehicle to the second vertical load of the rear axle of the vehicle.

[0027] In one possible implementation, the first target hydraulic pressure is the minimum hydraulic pressure between the first hydraulic pressure and the second hydraulic pressure, the first hydraulic pressure is the hydraulic pressure that the hydraulic device should provide when the front axle generates a first braking force, the second hydraulic pressure is the hydraulic pressure that the hydraulic device should provide when the rear axle generates a second braking force, the first braking force and the second braking force are the braking forces that should be allocated to the front axle and the rear axle respectively when the total braking force is allocated to the front axle and the rear axle according to the first vertical load and the second vertical load; and the electric braking force provided by the motor device to the first axle of the front axle and the rear axle is zero, and the first axle is the axle corresponding to the minimum hydraulic pressure.

[0028] In one possible implementation, the control module is further used to: determine the first braking force that should be allocated to the front axle and the second braking force that should be allocated to the rear axle when the total braking force is distributed to the front axle and the rear axle according to the first vertical load and the second vertical load; determine the first hydraulic pressure that the hydraulic device should provide when the front axle generates the first braking force; determine the second hydraulic pressure that the hydraulic device should provide when the rear axle generates the second braking force; determine the minimum hydraulic pressure between the first hydraulic pressure and the second hydraulic pressure as the first target hydraulic pressure; determine the hydraulic braking force generated by the second axle of the front axle and the rear axle when the hydraulic device provides the first target hydraulic pressure to the second axle; and determine the difference between the braking force that should be allocated to the second axle in the total braking force and the hydraulic braking force generated by the second axle as the target electric braking force that the motor device should provide for the second axle.

[0029] In one possible implementation, the control module is also used to: if the maximum electric braking force that the motor device can provide to the second shaft is greater than or equal to the target electric braking force, control the hydraulic device in the vehicle to provide the first target hydraulic pressure to the front and rear axles, and control the motor device in the vehicle to provide the target electric braking force to the second shaft.

[0030] In one possible implementation, if the maximum electric braking force that the motor device can provide to the second axle is less than the target electric braking force, the control module is also used to: determine a second target hydraulic pressure, the third sum of the third hydraulic braking force generated by the second target hydraulic pressure on the front axle and the fourth hydraulic braking force generated by the second target hydraulic pressure on the rear axle is equal to the difference between the total braking force and the maximum electric braking force; control the hydraulic device in the vehicle to provide the second target hydraulic pressure to the front axle and the rear axle, and control the motor device in the vehicle to provide the maximum electric braking force to the second axle.

[0031] In one possible implementation, the control module is also used to: when preset conditions are met, control the hydraulic device in the vehicle to provide a first target hydraulic pressure to the front axle and the rear axle according to the total braking force, and control the motor device in the vehicle to provide a first electric braking force to the front axle and a second electric braking force to the rear axle. The preset conditions include: the rate of change of the brake pedal in the vehicle is greater than a preset first threshold, the opening of the brake pedal is greater than a preset second threshold, and the slip rate of the vehicle is greater than a preset third threshold.

[0032] In one possible implementation, the control module is further configured to: obtain mode setting information in the vehicle, the mode setting information including first mode information and / or second mode information, the first mode information indicating that, when the total braking force remains unchanged, a ratio of the braking force of the front axle to the braking force of the rear axle is equal to a ratio of the first vertical load to the second vertical load, and the second mode information indicating that, when the total braking force remains unchanged, the motor device provides maximum electric braking force for the rear axle; when the mode setting information is the first mode information and the vehicle does not meet a preset condition, control the hydraulic device in the vehicle to provide a first target hydraulic pressure to the front and rear axles according to the total braking force, and control the motor device in the vehicle to provide a first electric braking force to the front axle and a second electric braking force to the rear axle, the preset condition including any one or more of the following conditions: a rate of change of a brake pedal in the vehicle is greater than a preset first threshold, a brake pedal opening is greater than a preset second threshold, and a slip ratio of the vehicle is greater than a preset third threshold.

[0033] In one possible implementation, when the mode setting information is the second mode information, the control module is further used to: determine the maximum electric braking force that the motor device can provide to the rear axle; determine a third target hydraulic pressure, the fourth sum of the fifth hydraulic braking force generated by the third target hydraulic pressure on the front axle and the sixth hydraulic braking force generated by the third target hydraulic pressure on the rear axle is equal to the difference between the total braking force and the maximum electric braking force that can be provided to the rear axle; control the hydraulic device in the vehicle to provide the third target hydraulic pressure to the front and rear axles, and provide the maximum electric braking force to the rear axle through the motor device.

[0034] In a third aspect, the present application provides a vehicle braking device, comprising: a memory and a processor; the memory is used to store program instructions; the processor is used to call the program instructions in the memory to execute the method described in the first aspect or any possible implementation method thereof.

[0035] In a fourth aspect, the present application provides a vehicle comprising the device as described in the second aspect or any possible implementation thereof.

[0036] In a fifth aspect, the present application provides a computer-readable medium, wherein the computer-readable medium stores a program code for computer execution, wherein the program code includes instructions for executing the method described in the first aspect or any possible implementation thereof.

[0037] In a sixth aspect, the present application provides a computer program product, which includes a computer program code. When the computer program code runs on a computer, the computer implements the method described in the first aspect or any possible implementation method thereof.

[0038] In this application, the technical effects of any one of the second to sixth aspects can be referred to the first aspect and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] FIG1 is a schematic structural diagram of a braking system in an automobile provided by the present application;

[0040] FIG2 is a schematic diagram of the front axle braking force and the rear axle braking force when the vehicle is braking provided by the present application;

[0041] FIG3 is a schematic diagram of front and rear axle braking force distribution according to an embodiment of the present application;

[0042] FIG4 is a schematic diagram of a braking system for a vehicle provided by the present application during braking;

[0043] FIG5 is a schematic flow chart of a vehicle braking method provided in one embodiment of the present application;

[0044] FIG6 is a schematic flow chart of a vehicle braking method provided in another embodiment of the present application;

[0045] FIG7 is a flow chart of a mode selection process according to an embodiment of the present application;

[0046] FIG8 is a schematic diagram illustrating the process of activating and exiting a braking method according to an embodiment of the present application;

[0047] FIG9 is a structural schematic diagram of a braking device provided in one embodiment of the present application;

[0048] FIG10 is a structural schematic diagram of a braking device provided in another embodiment of the present application. DETAILED DESCRIPTION

[0049] As a rapidly developing vehicle type, new energy vehicles have a direct impact on traffic safety. Braking is the process of forcibly slowing down or even stopping a moving vehicle according to the requirements of the driver or controller.

[0050] FIG1 is a schematic structural diagram of a braking system in an automobile provided by the present application. As shown in FIG1 , the braking system 100 includes a brake pedal 101 , a controller 102 , a hydraulic brake device 103 , a motor brake device 104 , and wheels 105 .

[0051] For the braking system 100 shown in Figure 1, when the driver depresses the brake pedal 101, braking occurs primarily through two pathways: hydraulic braking and electric braking. Specifically, for hydraulic braking, when the driver depresses the brake pedal 101, the controller 102 transmits the braking force generated by the driver depressing the brake pedal 101 to the hydraulic brake device 103. The master cylinder, hydraulic lines, and brake calipers within the hydraulic brake device 102 then apply the braking force to the wheels 105 based on controlled hydraulic pressure, thereby braking the vehicle. For electric braking, when the driver depresses the brake pedal 101, the controller 102 controls the drive motor within the electric brake device 104 to generate reverse torque, which acts directly on the wheels 105 via transmission components, thereby braking the vehicle.

[0052] It should be noted that, whether it is hydraulic braking or electric braking, when acting on the wheels to achieve braking, it is necessary to determine the ratio of the braking force allocated to the front axle and the braking force of the rear axle of the vehicle, which is also referred to as the ratio of the front and rear axle braking force distribution in this application.

[0053] More specifically, for the braking system 100 shown in FIG1 , when a vehicle is braked by hydraulic pressure, as shown in FIG2 , the braking process is as follows: when the driver depresses the brake pedal, the total braking force required for the vehicle to brake is determined, and then based on the friction coefficient of the front axle and the friction coefficient of the rear axle of the vehicle, the hydraulic pressure required to provide the total braking force through the front axle and the rear axle of the vehicle is determined, and the hydraulic pressure is provided to the front axle and the rear axle of the vehicle to generate the braking force F of the front axle respectively. x1 and the rear axle braking force F x2 , thereby achieving vehicle braking.

[0054] Furthermore, when hydraulically braking a vehicle, the friction coefficients of the front and rear axles are fixed. Therefore, when the vehicle is actually braking, the ratio of the front axle braking force to the rear axle braking force is typically a fixed value. In other words, when the vehicle is hydraulically braking, the ratio of the actual front axle braking force to the actual rear axle braking force is a fixed value.

[0055] In practice, when a vehicle brakes hydraulically, the distribution of braking force between the front and rear axles should satisfy the I-curve. Each point on the I-curve represents the appropriate distribution of braking force between the front and rear axles for the total braking force. In other words, the optimal distribution of braking force between the front and rear axles corresponding to any point on the I-curve is achieved. For more information on the I-curve, please refer to the detailed descriptions in the related art and will not be elaborated here.

[0056] For example, FIG3 is a schematic diagram of the front and rear axle braking force distribution provided by an embodiment of the present application. As shown in FIG3 , the horizontal axis represents the braking force of the front axle (unit value kilonewtons), and the vertical axis represents the braking force of the rear axle (unit value kilonewtons). The optimal distribution of the ideal front axle braking force and the rear axle braking force when the vehicle is braking should satisfy the I curve, while the front axle braking force and the rear axle braking force actually generated when the vehicle is braking satisfy the β line. By comparison, it can be seen that when the friction coefficient of the front axle and the friction coefficient of the rear axle of the vehicle are fixed, except for a certain working condition in which the distribution of the front axle braking force and the rear axle braking force in the vehicle satisfies the I curve (i.e., the distribution of the front axle braking force and the rear axle braking force at the intersection of the I curve and the β line in FIG3 ), in most other working conditions, the distribution of the front axle braking force and the rear axle braking force is not the most ideal distribution, and there is a certain gap with the I curve. Therefore, under the distribution of the actual braking force of the front axle and the actual braking force of the rear axle corresponding to the β line, the vehicle may experience the situation where the rear wheels lock and skid first and then the front wheels lock and skid, that is, the vehicle is unstable during braking.

[0057] In addition, the distribution of braking force between the front axle and the rear axle not only affects the stability of the vehicle, but also affects the comfort of the vehicle during braking and the energy recovery efficiency during braking.

[0058] In view of this, an embodiment of the present application provides a vehicle braking method, which realizes the distribution of the braking force of the front axle and the braking force of the rear axle of the vehicle through a hybrid method of hydraulic braking and motor braking. Thereby, the stability of the vehicle during braking can be achieved, and further, the comfort of the vehicle during braking and the energy recovery efficiency during braking can be improved. The method can be run in a brake controller or a vehicle controller. For example, Figure 4 is a schematic diagram of the braking system provided by the present application during vehicle braking. As shown in Figure 4, the system 400 includes: a vehicle state measurement and estimation module 401, a brake controller or a vehicle controller 402, a perception module 403, a motor device 404 and a hydraulic device 405.

[0059] The vehicle state measurement and estimation module 401 is used to measure and estimate the vehicle state necessary for realizing the function of distributing the braking force of the front axle and the braking force of the rear axle, such as the vehicle longitudinal acceleration, road slope, wheel speed and other vehicle states.

[0060] The brake controller or vehicle controller 402 is used to determine the total braking force when the vehicle is braking and to execute the vehicle braking method proposed in this application, and to realize the distribution of the braking force of the front axle and the braking force of the rear axle by controlling the motor device 404 and the hydraulic device 405.

[0061] Perception module 403: used to perceive the driving intention of the driver or the autonomous driving vehicle, wherein the driving intention in this application mainly refers to the intention of the driver or the autonomous driving vehicle to brake the vehicle.

[0062] Motor assembly 404: Executes the front and / or rear axle braking forces calculated by the brake controller or vehicle controller 402. It should be noted that the specific form of motor assembly 404 is not limited in this embodiment of the present application. For example, it can be a single-motor assembly, a two-motor assembly, a three-motor assembly, or a four-motor assembly.

[0063] Hydraulic device 405 : The hydraulic device 405 performs calculations from the brake controller or the vehicle controller 402 to distribute the braking force of the front axle and / or the braking force of the rear axle.

[0064] It should be noted that the embodiments of the present application can be applied to artificial intelligence driving scenarios, and can also be expanded to autonomous driving scenarios or manual driving scenarios.

[0065] FIG5 is a diagram of a vehicle braking method provided by an embodiment of the present application. As shown in FIG5 , the method includes S501 and S502. The method of the present application can be executed by the braking system shown in FIG4 .

[0066] S501: Obtain a total braking force, where the total braking force is the braking force required for the vehicle to brake.

[0067] Braking refers to forcibly slowing down or even stopping a moving vehicle as directed by the driver or controller. In this embodiment, total braking force refers to the amount of braking force required to brake the vehicle. For example, the total braking force required to bring the vehicle from a moving state to a stopped state.

[0068] It should be noted that the embodiment of the present application does not limit the method of obtaining the total braking force.

[0069] In one possible implementation, when the vehicle is manually driven, the total braking force can be determined based on the state of the brake pedal depressed by the driver. For example, the total braking force can be determined based on the degree of brake pedal opening. It should be understood that different degrees of brake pedal opening will result in different total braking forces required to brake the vehicle.

[0070] In another possible implementation, when the vehicle is autonomous, the total braking force required can be determined based on road condition information collected by the autonomous vehicle. For example, if the collected information determines that the traffic light at the upcoming intersection is red and the vehicle is currently traveling too fast, the vehicle will automatically determine the total braking force required.

[0071] S502, controlling the hydraulic device in the vehicle to provide a first target hydraulic pressure to the front axle and the rear axle according to the total braking force, and controlling the motor device in the vehicle to provide a first electric braking force to the front axle and a second electric braking force to the rear axle, wherein the sum of the first hydraulic braking force generated on the front axle by the first target hydraulic pressure, the second hydraulic braking force generated on the rear axle by the first target hydraulic pressure, the first electric braking force, and the second electric braking force is equal to the total braking force, and the ratio of the first sum of the first hydraulic braking force and the first electric braking force to the second sum of the second hydraulic braking force and the second electric braking force is equal to the ratio of the first vertical load of the front axle of the vehicle to the second vertical load of the rear axle of the vehicle.

[0072] The vertical load on the front axle can be considered as the force acting vertically on the front axle by the vehicle, and the vertical load on the rear axle can be considered as the force acting vertically on the rear axle by the vehicle.

[0073] It should be noted that the vertical load on the front axle (also referred to herein as the first vertical load) and the vertical load on the rear axle (also referred to herein as the second vertical load) are important factors affecting the distribution of braking force between the front and rear axles. These vertical loads are, in turn, affected by the vehicle's braking acceleration during braking. For example, during emergency braking, inertia can cause significant axle load shift, increasing the vertical load on the front axle and decreasing the vertical load on the rear axle. Therefore, the axle load shift caused by braking also affects the distribution of braking force between the front and rear axles through the vertical loads.

[0074] Typically, once the vertical load on the front axle and the vertical load on the rear axle are determined, and the total braking force is determined, the braking force to be allocated to the front axle and the braking force to be allocated to the rear axle can be determined. Specifically, the ratio of the braking force on the front axle to the braking force on the rear axle is the ratio of the vertical load on the front axle to the vertical load on the rear axle. In this application, the braking force to be allocated to the front axle is also referred to as the first braking force, and the braking force to be allocated to the rear axle is also referred to as the second braking force.

[0075] It should be noted that the braking force to be allocated to the front axle and the braking force to be allocated to the rear axle herein refer to the braking force of the front axle and the braking force of the rear axle located on the I curve. In other words, if, in the present application, when providing braking force to the front axle and the braking force to the rear axle, the braking force provided to the front axle is the first braking force and the braking force provided to the rear axle is the second braking force, then the braking force of the front axle and the braking force of the rear axle are located on the I curve, thereby ensuring the stability of the vehicle during braking.

[0076] However, it should be understood that when hydraulic braking is used, the hydraulic pressure provided by the hydraulic braking device to the front axle and the hydraulic pressure provided to the rear axle are the same. This is because the friction coefficients of the front and rear axles are different, resulting in different braking forces generated by the hydraulic braking device when the same hydraulic pressure is applied to the front and rear axles. Therefore, it is understood that under most operating conditions, the braking force on the front and rear axles provided solely by hydraulic braking does not satisfy the requirement that the ratio of the front axle braking force to the rear axle braking force is the ratio of the vertical load on the front axle to the vertical load on the rear axle. In view of this, in this embodiment, the vehicle is braked using both hydraulic braking and electric motor braking, such that the sum of the braking force generated by the hydraulic pressure acting on the front axle and the braking force provided by the electric motor for the front axle (also referred to as the first sum) is the first braking force, and the sum of the braking force generated by the hydraulic pressure acting on the rear axle and the braking force provided by the electric motor for the rear axle (also referred to as the second sum) is the second braking force. That is, the vehicle is braked by both hydraulic braking and electric braking so that the ratio of the braking force of the front axle to the braking force of the rear axle is equal to the ratio of the vertical load of the front axle to the vertical load of the rear axle, thereby being located on the I curve to ensure the stability of the vehicle during braking.

[0077] As an example, in this embodiment, after a certain hydraulic pressure (also called the first target hydraulic pressure) is determined, the braking force generated on the front axle (also called the first hydraulic braking force) and the braking force generated on the rear axle (also called the second hydraulic braking force) by the first target hydraulic pressure can be calculated first, and then the difference between the first braking force and the first hydraulic braking force is calculated (for example, the obtained difference is referred to as the front axle electric braking force compensation value) to obtain the electric braking force that the motor device should provide for the front axle (also called the first electric braking force), and the difference between the second braking force and the second hydraulic braking force is calculated (for example, the obtained difference is referred to as the rear axle electric braking force compensation value) to obtain the electric braking force that the motor device should provide for the rear axle (also called the second electric braking force). Finally, when braking, the first target hydraulic pressure is provided to the front axle and the rear axle, and the first electric braking force is provided to the front axle through the motor device, and the second electric braking force is provided to the rear axle by the motor device.

[0078] In the vehicle braking method provided in this application, after obtaining the total braking force required to brake the vehicle, in addition to applying braking force to the front and rear axles using the hydraulic device to provide a first target hydraulic pressure, the motor device also provides braking force to the front and rear axles, respectively. That is, in this embodiment, the braking force provided to the front axle is the sum of the braking force provided to the front axle by the first target hydraulic pressure and the braking force provided to the front axle by the motor device, and the braking force provided to the rear axle is the sum of the braking force provided to the rear axle by the first target hydraulic pressure and the braking force provided to the rear axle by the motor device. Furthermore, because in this embodiment, the ratio of the braking force provided to the front axle to the braking force provided to the rear axle is the same as the ratio of the first vertical load on the front axle to the second vertical load on the rear axle of the vehicle, the braking force on the front axle and the braking force on the rear axle determined by the braking method of this embodiment lie on an I curve, thereby helping to prevent possible vehicle instability during braking.

[0079] In one possible implementation, the first target hydraulic pressure in this application is the minimum of the first and second hydraulic pressures. The first hydraulic pressure is the hydraulic pressure that the hydraulic device should provide to generate a first braking force on the front axle, and the second hydraulic pressure is the hydraulic pressure that the hydraulic device should provide to generate a second braking force on the rear axle. The first and second braking forces are the braking forces that should be allocated to the front and rear axles, respectively, when the total braking force is allocated to the front and rear axles based on the first and second vertical loads. In this solution, the electric braking force provided by the motor device to the first of the front and rear axles is zero, and the first axle corresponds to the minimum hydraulic pressure.

[0080] For ease of understanding, the braking method of this embodiment is described in detail with reference to FIG6 . The method includes:

[0081] S601: Obtain a total braking force, where the total braking force is the braking force required for the vehicle to brake.

[0082] For a detailed description of this step, please refer to the description of S501 in the embodiment described in FIG5 , which will not be repeated here.

[0083] S602 : Determine a first braking force to be allocated to the front axle and a second braking force to be allocated to the rear axle according to a vertical load on the front axle of the vehicle and a vertical load on the rear axle of the vehicle.

[0084] In specific implementation, if the total braking force is expressed as f b , the vertical load on the front axle during braking is expressed as f z1 , the vertical load on the rear axle during braking is expressed as f z2 , the braking force to be distributed to the front axle (i.e. the first braking force) is expressed as f b1 , the braking force to be distributed to the rear axle (i.e. the second braking force) is expressed as f b2 ,So:

[0085] as well as

[0086] It should be noted that the first braking force and the second braking force calculated in this manner correspond to a point on the I-curve. That is, the braking force to be distributed to the front axle and the braking force to be distributed to the rear axle, respectively calculated based on the vertical load on the front axle and the vertical load on the rear axle, are the best or optimal distribution.

[0087] S603, determining a first hydraulic pressure according to the first braking force, and determining a second hydraulic pressure according to the second braking force, wherein the first hydraulic pressure is the hydraulic pressure required to achieve the first braking force of the front axle, and the second hydraulic pressure is the hydraulic pressure required to achieve the second braking force of the rear axle.

[0088] It should be understood that when hydraulic braking is used, the braking force allocated to the front axle or the braking force allocated to the rear axle is achieved by controlling the hydraulic pressure. In other words, when the hydraulic pressure is different, the braking force allocated to the front axle and the braking force allocated to the rear axle are also different.

[0089] Therefore, in this embodiment, after determining the first braking force to be allocated to the front axle and the second braking force to be allocated to the rear axle respectively, the hydraulic pressure required to achieve the first braking force of the front axle (also called the first hydraulic pressure) and the hydraulic pressure required to achieve the second braking force of the rear axle (also called the second hydraulic pressure) are also determined.

[0090] In a specific implementation, if the first hydraulic pressure is expressed as p1 and the second hydraulic pressure is expressed as p2, then:

[0091] as well as

[0092] Wherein, c1 represents the friction coefficient of the front axle, and c2 represents the friction coefficient of the rear axle. For the concepts of the friction coefficient of the front axle and the friction coefficient of the rear axle, reference can be made to the description in the related art and will not be repeated here.

[0093] S604: Determine the minimum hydraulic pressure between the first hydraulic pressure and the second hydraulic pressure as the first target hydraulic pressure, and determine the hydraulic braking force generated by the second shaft when the hydraulic device provides the first target hydraulic pressure to the second shaft of the front shaft and the rear shaft.

[0094] It should be noted that when using hydraulic braking, the hydraulic pressure provided by the hydraulic braking device to the front axle and the hydraulic pressure provided to the rear axle are the same. However, because the friction coefficient of the front axle and the friction coefficient of the rear axle are inconsistent, when the hydraulic braking device provides the same hydraulic pressure to the front axle and the rear axle, the braking force generated by the front axle and the braking force generated by the rear axle are different.

[0095] Specifically, when using hydraulic braking, if the hydraulic pressure provided by the hydraulic braking device is recorded as p, then the braking force generated by the front axle is the product of p and the friction coefficient c1 of the front axle, and the braking force generated by the rear axle is the product of p and the friction coefficient c2 of the rear axle.

[0096] S605 : Determine the difference between the braking force to be allocated to the second shaft in the total braking force and the hydraulic braking force generated by the second shaft as the target electric braking force to be provided by the motor device for the second shaft.

[0097] It is understood that when the minimum hydraulic pressure is used as the hydraulic pressure provided during hydraulic braking, the braking force of the axle corresponding to the minimum hydraulic pressure can be met. For example, if the first hydraulic pressure is less than the second hydraulic pressure, then the first hydraulic pressure can be used as the hydraulic pressure provided during hydraulic braking to meet the first braking force of the front axle. If the second hydraulic pressure is less than the first hydraulic pressure, then the second hydraulic pressure can be used as the hydraulic pressure provided during hydraulic braking to meet the second braking force of the rear axle.

[0098] It can also be understood that when the minimum hydraulic pressure of the first hydraulic pressure and the second hydraulic pressure is used as the hydraulic pressure provided when using hydraulic braking, for the axis corresponding to the maximum hydraulic pressure of the first hydraulic pressure and the second hydraulic pressure (also referred to as the second axis in this application), the braking force provided by the minimum hydraulic pressure for the second axis is less than the braking force that should be allocated to the second axis when the total braking force is distributed according to the vertical load, that is, the braking force provided by the minimum hydraulic pressure is insufficient. In other words, there is a difference between the braking force provided by the minimum hydraulic pressure for the second axis and the ideal braking force of the second axis. In this case, in this embodiment, the first compensating electric braking force (also referred to as the target electric braking force) is determined based on the maximum hydraulic pressure of the first hydraulic pressure and the second hydraulic pressure, wherein the target electric braking force is used to make the braking force of the second axis equal to the braking force that should be allocated to the second axis when the total braking force is distributed according to the vertical load when the minimum hydraulic pressure is provided to the target axis.

[0099] As an example, the target electric braking force is the braking force difference between the braking force provided by the minimum hydraulic pressure to the second shaft and the braking force that should be allocated to the second shaft when the total braking force is distributed according to the vertical load. If the minimum hydraulic pressure of the first hydraulic pressure and the second hydraulic pressure is represented by p min , the target electric braking force is expressed as f 补偿 ,but:

[0100] f 补偿 =f b -(c1+c2)p min

[0101] S606 , providing a minimum hydraulic pressure to the vehicle through the hydraulic device and providing a target electric braking force to the second shaft through the motor device.

[0102] In this embodiment, when the minimum hydraulic pressure and the target electric braking force are determined and when it is determined that the maximum electric braking force that the motor device can provide to the second shaft is greater than or equal to the target electric braking force, the minimum hydraulic pressure is provided to the vehicle through the hydraulic device and the target electric braking force is provided to the second shaft through the motor device to provide a total braking force for the vehicle to achieve braking of the vehicle.

[0103] The vehicle braking method provided by the present application, after obtaining the total braking force required to achieve vehicle braking, first determines the optimal front axle braking force and rear axle braking force based on the vertical load of the front axle and the vertical load of the rear axle respectively, and then determines the sum of the optimal front axle hydraulic pressure and rear axle hydraulic pressure based on the optimal front axle braking force and rear axle braking force, and then uses the minimum hydraulic pressure of the optimal front axle hydraulic pressure and the rear axle hydraulic pressure as the hydraulic pressure when providing braking force to the vehicle through the hydraulic device. It can be understood that when the minimum hydraulic pressure is used to provide braking force to the vehicle , which ensures that the braking force on the axis corresponding to the minimum hydraulic pressure is optimal. However, for the braking force on the second axis corresponding to the maximum hydraulic pressure, the braking force provided by the minimum hydraulic pressure for the second axis cannot reach the optimal braking force of the second axis. In the embodiment of the present application, in order to enable the braking force of the second axis to reach the optimal braking force of the target axis, a target electric braking force is also provided to the target axis by a motor device, wherein the target electric braking force is the braking force difference between the braking force provided by the minimum hydraulic pressure for the second axis and the braking force that should be allocated to the second axis when the total braking force is distributed according to the vertical load. Therefore, the technical solution provided by the present application helps to improve the stability of the vehicle during braking.

[0104] It is understandable that there may be a situation where the maximum electric braking force that the motor device can provide for the second shaft is less than the target electric braking force. For example, the maximum electric braking force that the motor device can provide for the second shaft as defined by the current vehicle status regulations is less than the target electric braking force determined in this application, or the upper limit of the electric braking force that the motor device can provide for the second shaft is less than the target electric braking force determined in this application. In an embodiment of the present application, when the maximum electric braking force that the motor device can provide for the second shaft is less than the target electric braking force, the method of the present application further includes: determining a second target hydraulic pressure, the third sum of the third hydraulic braking force generated by the second target hydraulic pressure on the front axle and the fourth hydraulic braking force generated by the second target hydraulic pressure on the rear axle is equal to the difference between the total braking force and the maximum electric braking force; controlling the hydraulic device in the vehicle to provide the second target hydraulic pressure to the front and rear axles, and controlling the motor device in the vehicle to provide the maximum electric braking force for the second shaft.

[0105] In specific implementation, if the maximum electric braking force that the motor device can provide to the second shaft is less than the target electric braking force due to the capacity limitation of the motor device or the battery capacity limitation, the maximum electric braking force provided by the motor device for the second shaft is taken, and the remaining braking force is compensated by hydraulic pressure (also referred to as the second target hydraulic pressure in this application).

[0106] For example, in one possible implementation, the second target hydraulic pressure is the quotient of the first braking force difference and the target friction coefficient, wherein the first braking force difference is the difference between the total braking force and the maximum electric braking force that the motor device can provide for the second shaft, and the target friction coefficient is the sum of the friction coefficients of the front wheels and the friction coefficients of the rear wheels. For example, if the maximum electric braking force provided by the motor device for the second shaft is represented by f 电-max , the second target hydraulic pressure is expressed as p 补偿 , then the first braking force difference can be expressed as f b -f 电-max , further:

[0107]

[0108] Alternatively, p can be calculated using the following formula 补偿 :

[0109] Δf=f 补偿 -f 电-max

[0110]

[0111] Among them, f 补偿 The concepts of c1 and c2 can be referred to the description in the aforementioned embodiments and will not be repeated here.

[0112] In this embodiment, when the maximum electric braking force that the motor device can provide to the second shaft is less than the target electric braking force, this embodiment provides the maximum electric braking force to the second shaft through the motor device, and compensates for the remaining insufficient braking force through hydraulic pressure, so that the actual braking force of the vehicle is consistent with the total braking force, thereby enabling the vehicle to brake.

[0113] As an optional embodiment, the above-described control of the hydraulic device in the vehicle to provide the first target hydraulic pressure to the front and rear axles based on the total braking force, and the control of the motor device in the vehicle to provide the first electric braking force to the front axle and the second electric braking force to the rear axle, as described in the present application, can be performed only when preset conditions are met. For example, the preset conditions include: the rate of change of the brake pedal in the vehicle is greater than a preset first threshold, the opening of the brake pedal is greater than a preset second threshold, and the slip ratio of the vehicle is greater than a preset third threshold. In other words, the process of S502 in the present application is only performed when the rate of change of the brake pedal in the vehicle is greater than the preset first threshold, the opening of the brake pedal is greater than the preset second threshold, or the slip ratio of the vehicle is greater than the preset third threshold.

[0114] It should be noted that this embodiment does not limit the specific values ​​of the first threshold, the second threshold, and the third threshold, which can be determined according to different needs.

[0115] As an optional embodiment, in the present application, mode setting information in the vehicle may be first obtained, the mode setting information including first mode information and / or second mode information, the first mode information indicating that the ratio of the braking force of the front axle to the braking force of the rear axle is equal to the ratio of the first vertical load to the second vertical load when the total braking force remains unchanged, and the second mode information indicating that the motor device provides the maximum electric braking force for the rear axle when the total braking force remains unchanged; when the mode setting information is the first mode information and the vehicle does not meet the preset conditions, the process of S502 in the present application is executed again. The preset conditions include any one or more of the following conditions: the rate of change of the brake pedal in the vehicle is greater than a preset first threshold, the opening of the brake pedal is greater than a preset second threshold, and the slip rate of the vehicle is greater than a preset third threshold.

[0116] It can be understood that when the total braking force remains unchanged, the ratio of the braking force of the front axle to the braking force of the rear axle is equal to the ratio of the first vertical load to the second vertical load, which can ensure the stability of the vehicle during braking. Therefore, in this application, the first mode information is also referred to as the stable mode.

[0117] It is understandable that when the motor device provides the maximum electric braking force to the rear axle while the total braking force remains unchanged, the driver's comfort can be improved. Therefore, in this embodiment, the second mode information is also referred to as the comfort mode.

[0118] Optionally, this embodiment may also include an economic mode, wherein the economic mode means that the electric braking force provided by the motor device to the front axle and the electric braking force provided to the rear axle is maximized while ensuring that the total braking force remains unchanged, so as to improve energy recovery efficiency.

[0119] That is to say, in this application, multiple mode selections can be made. For example, FIG7 is a flow diagram of mode selection provided by an embodiment of this application. As shown in FIG7 , the mode selection process includes:

[0120] S701, obtaining the vehicle setting mode.

[0121] For example, the vehicle provides a human-machine interaction method for the driver to set the desired mode; or the vehicle can automatically identify the driver's driving style and automatically set the driver's desired mode.

[0122] S702, monitor whether the rate of change of the brake pedal is greater than the first threshold, or the opening of the brake pedal is greater than the preset second threshold, or the slip rate of the vehicle is greater than the preset third threshold. If so, execute S703, if not, execute S704.

[0123] S703: Determine whether the braking mode of the vehicle is a stable mode.

[0124] That is, when the rate of change of the monitoring pedal is greater than the first threshold, or the opening of the brake pedal is greater than the second threshold, or the slip rate of the vehicle is greater than the third threshold, the vehicle's braking mode is determined to be the stable mode.

[0125] S704, determine whether the vehicle setting mode is stable mode, if so, execute S703, if not, execute S705.

[0126] That is, when the rate of change of the monitoring pedal is not greater than the first threshold, the opening of the brake pedal is not greater than the second threshold, and the slip rate of the vehicle is not greater than the third threshold, it is determined whether the mode set by the vehicle is the stable mode.

[0127] S705, determine whether the vehicle mode is set to the economic mode, if so, execute S706, if not, execute S707.

[0128] S706: Determine that the braking mode of the vehicle is the economic mode.

[0129] S707: Determine that the vehicle is in comfort mode.

[0130] As an optional embodiment, in the present application, when the mode setting information is the second mode information (that is, the selected mode is the comfort mode), the method also includes: determining the maximum electric braking force that the motor device can provide to the rear axle; determining a third target hydraulic pressure, the fourth sum of the fifth hydraulic braking force generated by the third target hydraulic pressure on the front axle and the sixth hydraulic braking force generated by the third target hydraulic pressure on the rear axle is equal to the difference between the total braking force and the maximum electric braking force that can be provided to the rear axle; controlling the hydraulic device in the vehicle to provide the third target hydraulic pressure to the front and rear axles, as well as the maximum electric braking force provided to the rear axle by the motor device.

[0131] That is to say, in this application, when the selected mode is comfort mode, while ensuring that the total braking force remains unchanged, the maximum electric braking force is achieved for the rear axle through the motor device as much as possible, while the hydraulic braking is made to ensure the system stability as much as possible.

[0132] In specific implementation, it may include:

[0133] Step 1: Calculate the maximum electric braking force that the motor device can achieve for the rear axle based on the total braking force requirement, rear axle motor capacity limit, battery capacity limit, rear axle vertical force, and slope. Assume that the maximum braking force that the motor device can achieve for the rear axle is expressed as f 后-max .

[0134] Step 2: Based on the comparison between the current motor braking force and the total braking force requirement, the excess braking force is realized by hydraulic braking. Specifically, the required hydraulic pressure is expressed as p 舒适模式补偿 ,but:

[0135]

[0136] In this embodiment, it is possible to achieve maximum braking force through the rear axle motor while ensuring that the total braking force remains unchanged, thereby helping to improve the driver's comfort during braking.

[0137] As an optional embodiment, in the present application, the mode setting information may also include third mode information (that is, the selected mode is comfort mode), wherein the third mode information indicates that when the total braking force remains unchanged, the braking force provided by the motor device to the front axle and the braking force provided to the rear axle are as large as possible, thereby improving the energy recovery efficiency.

[0138] The specific implementation may include the following steps:

[0139] Step 1: Determine a first braking force to be allocated to the front axle and a second braking force to be allocated to the rear axle according to a vertical load on the front axle of the vehicle and a vertical load on the rear axle of the vehicle.

[0140] For example, the total braking force is expressed as f b , the vertical load on the front axle during braking is expressed as f z1 , the vertical load on the rear axle during braking is expressed as f z2 , the first braking force is expressed as f b1 , the second braking force is expressed as f b2 ,So:

[0141] as well as

[0142] Step 2: The motor device distributes the electric braking force of the front axle and the electric braking force of the rear axle according to the first braking force and the second braking force.

[0143] Specifically, the electric braking force of the front axle distributed by the motor device is expressed as f 电-前轴 , the electric braking force of the rear axle distributed by the motor device is expressed as f 电-后轴 , then the following will happen:

[0144] If the electric braking force that can be distributed to the front axle and the electric braking force that can be distributed to the rear axle by the electric motor device are not limited by the capacity of the electric motor, then:

[0145] f 电-前轴 =f b1 , f 电-后轴 =f b2 .

[0146] If the electric braking force that can be distributed by the motor device to the front axle is limited by the capacity of the motor device, and the electric braking force that can be distributed by the motor device to the rear axle is not limited by the capacity of the motor device, and the maximum value of the electric braking force that can be distributed by the motor device to the front axle is recorded as f 电机-前轴,max ,but:

[0147] f 电-前轴 =f 电-前轴,max , f 电-后轴 =f b -f 电-前轴,max

[0148] If the electric braking force that can be distributed by the motor device to the rear axle is limited by the capacity of the motor device, and the electric braking force that can be distributed by the motor device to the front axle is not limited by the capacity of the motor device, and the maximum value of the electric braking force that can be distributed by the motor device to the rear axle is recorded as f 电-后轴,max ,but:

[0149] f 电-后轴 =f 电-后轴,max , f 电-前轴 =f b -f 电-后轴,max

[0150] If the braking force that can be distributed to the rear axle by the electric motor unit and the braking force that can be distributed to the rear axle are both limited by the capacity of the electric motor unit, then: 电-前轴 =f 电-前轴,max , f 电-后轴 =f 电-后轴,max In addition, in this case, in order to ensure that the total braking force remains unchanged, the remaining braking force is compensated by hydraulic pressure. Specifically, if the compensated hydraulic pressure is recorded as p 经济-液压补偿 ,but:

[0151]

[0152] In this embodiment, the braking force of the front axle and the braking force of the rear axle provided by the motor device can be as large as possible while ensuring that the total braking force remains unchanged, thereby improving the energy recovery efficiency.

[0153] The above describes how to distribute the front and rear axle braking forces in stable mode, comfort mode, and economy mode, respectively. It should be understood that when applying the braking method provided herein, attention should also be paid to the coordination of the method provided herein with other braking methods (e.g., braking methods implemented by an anti-lock braking system). Coordination can be considered to determine when the braking method provided herein can be activated and when it should be exited.

[0154] For example, Figure 8 is a schematic diagram illustrating the process of activating and exiting the braking method provided by one embodiment of the present application. As shown in Figure 8 , when the driver steps on the brake pedal or the intelligent driving system issues a braking command, the process shown in Figure 8 begins. The detailed process is described as follows:

[0155] S801: Obtain a total braking force based on the driver's braking demand or processing the intelligent driving system's braking demand.

[0156] S802, executing a multi-objective braking force distribution process.

[0157] The multi-target braking force distribution process is the same as the front and rear axle braking force distribution process in the stable mode, the front and rear axle braking force distribution process in the stable mode, or the front and rear axle braking force distribution process in the economy mode, as described in the previous embodiments of this application. The specific process can be referred to the previous description and will not be repeated here.

[0158] S803, determine whether the anti-lock braking system is activated, if so, execute S804, if not, execute S808.

[0159] S804, enter the braking method control of the anti-lock braking system.

[0160] The anti-lock braking system corresponds to a set of braking methods, which can also be considered as a method for distributing the braking force of a front axle and the braking force of a rear axle.

[0161] S805, determining whether the braking method of the anti-lock braking system is exited, if so, executing S806, otherwise, continuing to execute S804.

[0162] S806, fixed-proportional braking force distribution.

[0163] Among them, the fixed proportion distribution is: when the total braking force is determined, the hydraulic pressure required for the total braking force is calculated based on the friction coefficient of the front axle and the friction coefficient of the rear axle, and then the braking force of the front axle and the braking force of the rear axle are provided based on the hydraulic pressure.

[0164] S807, determine whether the braking demand or vehicle speed is 0, if it is 0, end the braking process, if not, continue to execute S806.

[0165] S808, determine whether the braking demand or vehicle speed is 0, if not, execute S802, if it is 0, end the braking process.

[0166] The braking method according to the embodiment of the present application is described in detail above with reference to FIG. 5 to FIG. 8 . The braking device according to the embodiment of the present application will be described in detail below with reference to FIG. 9 to FIG. 10 .

[0167] Figure 9 is a schematic structural diagram of a braking device provided by an embodiment of the present application. Specifically, as shown in Figure 9, the device 900 includes: an acquisition module 901 and a control module 902. The device 900 can be used to implement the method in any of the aforementioned method embodiments.

[0168] As an example, the acquisition module 901 may be used to implement S501, and the control module 902 may be used to implement S502.

[0169] As another example, the acquisition module 901 may be used to implement S601 , and the control module 902 may be used to implement S602 to S606 .

[0170] Figure 10 is a schematic structural diagram of a braking device provided in another embodiment of the present application. The device shown in Figure 10 can be used to execute the method described in any of the above embodiments.

[0171] As shown in Figure 10, the apparatus 1000 of this embodiment includes a memory 1001, a processor 1002, a communication interface 1003, and a bus 1004. The memory 1001, the processor 1002, and the communication interface 1003 are connected to each other via the bus 1004.

[0172] The memory 1001 may be a read-only memory (ROM), a static storage device, a dynamic storage device, or a random access memory (RAM). The memory 1001 may store a program. When the program stored in the memory 1001 is executed by the processor 1002, the processor 1002 is configured to perform the steps of the method shown in Figures 5 to 8.

[0173] The processor 1002 can be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits to execute relevant programs to implement the methods shown in Figures 5 to 8 of the present application.

[0174] The processor 1002 may also be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the method of FIG5 to FIG8 of the embodiment of the present application may be completed by an integrated logic circuit of hardware in the processor 1002 or by instructions in the form of software.

[0175] The processor 1002 may also be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component. The processor 1002 may implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of the present application. The general-purpose processor may be a microprocessor or any conventional processor.

[0176] The steps of the method disclosed in conjunction with the embodiments of the present application can be directly embodied as being executed by a hardware decoding processor, or can be executed by a combination of hardware and software modules in the decoding processor. The software module can be located in a storage medium mature in the art, such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory 1001, and the processor 1002 reads the information in the memory 1001 and, in combination with its hardware, completes the functions required to be performed by the units included in the device of the present application. For example, the various steps / functions of the embodiments shown in Figures 5 to 8 can be executed.

[0177] The communication interface 1003 may use, but is not limited to, a transceiver or other transceiver device to implement communication between the apparatus 1000 and other devices or a communication network.

[0178] The bus 1004 may include a path for transmitting information between various components of the device 1000 (eg, the memory 1001 , the processor 1002 , and the communication interface 1003 ).

[0179] It should be understood that the device 1000 shown in the embodiment of the present application may be an electronic device, or may be a chip configured in the electronic device.

[0180] The above embodiments can be implemented in whole or in part by software, hardware, firmware or any other combination. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer program are loaded or executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center via a wired (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that contains one or more available media sets. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium. The semiconductor medium can be a solid-state drive.

[0181] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not 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 embodiments of the present application.

[0182] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0183] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0184] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0185] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0186] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0187] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory, a random access memory, a magnetic disk, or an optical disk.

[0188] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A vehicle braking method, comprising: Obtaining a total braking force, where the total braking force is the braking force required to brake the vehicle; controlling a hydraulic device in the vehicle to provide a first target hydraulic pressure to the front axle and the rear axle according to the total braking force, and controlling an electric motor device in the vehicle to provide a first electric braking force to the front axle and a second electric braking force to the rear axle; Among them, the first hydraulic braking force generated by the first target hydraulic pressure on the front axle, the second hydraulic braking force generated by the first target hydraulic pressure on the rear axle, the sum of the first electric braking force and the second electric braking force is equal to the total braking force, and the ratio of the first sum of the first hydraulic braking force and the first electric braking force to the second sum of the second hydraulic braking force and the second electric braking force is equal to the ratio of the first vertical load of the front axle of the vehicle to the second vertical load of the rear axle of the vehicle.

2. The method according to claim 1, characterized in that The first target hydraulic pressure is the minimum hydraulic pressure of the first hydraulic pressure and the second hydraulic pressure. The first hydraulic pressure is the hydraulic pressure that the hydraulic device should provide when generating a first braking force on the front axle. The second hydraulic pressure is the hydraulic pressure that the hydraulic device should provide when generating a second braking force on the rear axle. The first braking force and the second braking force are the braking forces that should be allocated to the front axle and the rear axle, respectively, when the total braking force is allocated to the front axle and the rear axle according to the first vertical load and the second vertical load. Furthermore, the electric braking force provided by the motor device to the first of the front and rear axles is zero, and the first axle is the axle corresponding to the minimum hydraulic pressure.

3. The method according to claim 2, characterized in that The method further comprises: determining, when distributing the total braking force to the front axle and the rear axle according to the first vertical load and the second vertical load, a first braking force to be distributed to the front axle and a second braking force to be distributed to the rear axle; determining a first hydraulic pressure that the hydraulic device should provide in order to generate the first braking force on the front axle; determining a second hydraulic pressure that the hydraulic device should provide in order to generate the second braking force on the rear axle; determining the minimum hydraulic pressure between the first hydraulic pressure and the second hydraulic pressure as the first target hydraulic pressure; determining a hydraulic braking force generated by a second shaft of the front shaft and the rear shaft when the hydraulic device provides the first target hydraulic pressure to the second shaft; A difference between the braking force to be distributed to the second shaft in the total braking force and the hydraulic braking force generated by the second shaft is determined as a target electric braking force to be provided by the motor device to the second shaft.

4. The method according to claim 3, characterized in that The controlling of the hydraulic device in the vehicle to provide the first target hydraulic pressure for the front axle and the rear axle, and the controlling of the motor device in the vehicle to provide the first electric braking force for the front axle and the second electric braking force for the rear axle, comprises: If the maximum electric braking force that the motor device can provide to the second shaft is greater than or equal to the target electric braking force, the hydraulic device in the vehicle is controlled to provide the first target hydraulic pressure to the front and rear axles, and the motor device in the vehicle is controlled to provide the target electric braking force to the second shaft.

5. The method according to claim 4, characterized in that If the maximum electric braking force that the motor device can provide to the second shaft is less than the target electric braking force, the method further includes: determining a second target hydraulic pressure, wherein a third sum of a third hydraulic braking force generated on the front axle by the second target hydraulic pressure and a fourth hydraulic braking force generated on the rear axle by the second target hydraulic pressure is equal to a difference between the total braking force and the maximum electric braking force; A hydraulic device in the vehicle is controlled to provide the second target hydraulic pressure to the front and rear axles, and an electric motor device in the vehicle is controlled to provide the maximum electric braking force to the second axle.

6. The method according to any one of claims 1 to 5, characterized in that The controlling of the hydraulic device in the vehicle to provide a first target hydraulic pressure for the front axle and the rear axle according to the total braking force, and the controlling of the motor device in the vehicle to provide a first electric braking force for the front axle and a second electric braking force for the rear axle, comprises: When preset conditions are met, the hydraulic device in the vehicle is controlled to provide a first target hydraulic pressure for the front axle and the rear axle according to the total braking force, and the motor device in the vehicle is controlled to provide a first electric braking force for the front axle and a second electric braking force for the rear axle. The preset conditions include: the rate of change of the brake pedal in the vehicle is greater than a preset first threshold, the opening of the brake pedal is greater than a preset second threshold, and the slip rate of the vehicle is greater than a preset third threshold.

7. The method according to any one of claims 1 to 5, characterized in that The controlling of the hydraulic device in the vehicle to provide a first target hydraulic pressure for the front axle and the rear axle according to the total braking force, and the controlling of the motor device in the vehicle to provide a first electric braking force for the front axle and a second electric braking force for the rear axle, comprises: obtaining mode setting information in the vehicle, the mode setting information including first mode information and / or second mode information, the first mode information indicating that, when the total braking force remains unchanged, a ratio of the braking force of the front axle to the braking force of the rear axle is equal to a ratio of the first vertical load to the second vertical load, and the second mode information indicating that, when the total braking force remains unchanged, the electric motor device provides maximum electric braking force to the rear axle; When the mode setting information is the first mode information and the vehicle does not meet the preset conditions, the hydraulic device in the vehicle is controlled to provide the first target hydraulic pressure for the front axle and the rear axle according to the total braking force, and the motor device in the vehicle is controlled to provide the first electric braking force for the front axle and the second electric braking force for the rear axle. The preset conditions include any one or more of the following conditions: the rate of change of the brake pedal in the vehicle is greater than a preset first threshold, the opening of the brake pedal is greater than a preset second threshold, and the slip rate of the vehicle is greater than a preset third threshold.

8. The method according to claim 7, characterized in that It is characterized by: When the mode setting information is the second mode information, the method further includes: determining a maximum electric braking force that the electric motor assembly can provide to the rear axle; determining a third target hydraulic pressure, wherein a fourth sum of a fifth hydraulic braking force generated at the front axle by the third target hydraulic pressure and a sixth hydraulic braking force generated at the rear axle by the third target hydraulic pressure is equal to a difference between the total braking force and a maximum electric braking force that can be provided to the rear axle; A hydraulic device in the vehicle is controlled to provide a third target hydraulic pressure to the front and rear axles, and the maximum electric braking force is provided to the rear axle via the motor device.

9. A braking device for a vehicle, characterized in that: include: an acquisition module, configured to acquire a total braking force, where the total braking force is the braking force required to brake the vehicle; a control module, configured to control a hydraulic device in the vehicle to provide a first target hydraulic pressure to the front axle and the rear axle according to the total braking force, and to control an electric motor device in the vehicle to provide a first electric braking force to the front axle and a second electric braking force to the rear axle; Among them, the first hydraulic braking force generated by the first target hydraulic pressure on the front axle, the second hydraulic braking force generated by the first target hydraulic pressure on the rear axle, the sum of the first electric braking force and the second electric braking force is equal to the total braking force, and the ratio of the first sum of the first hydraulic braking force and the first electric braking force to the second sum of the second hydraulic braking force and the second electric braking force is equal to the ratio of the first vertical load of the front axle of the vehicle to the second vertical load of the rear axle of the vehicle.

10. The device according to claim 9, characterized in that The first target hydraulic pressure is the minimum hydraulic pressure of the first hydraulic pressure and the second hydraulic pressure. The first hydraulic pressure is the hydraulic pressure that the hydraulic device should provide when generating a first braking force on the front axle. The second hydraulic pressure is the hydraulic pressure that the hydraulic device should provide when generating a second braking force on the rear axle. The first braking force and the second braking force are the braking forces that should be allocated to the front axle and the rear axle, respectively, when the total braking force is allocated to the front axle and the rear axle according to the first vertical load and the second vertical load. Furthermore, the electric braking force provided by the motor device to the first of the front and rear axles is zero, and the first axle is the axle corresponding to the minimum hydraulic pressure.

11. The device according to claim 10, characterized in that The control module is further configured to: determining, when distributing the total braking force to the front axle and the rear axle according to the first vertical load and the second vertical load, a first braking force to be distributed to the front axle and a second braking force to be distributed to the rear axle; determining a first hydraulic pressure that the hydraulic device should provide in order to generate the first braking force on the front axle; determining a second hydraulic pressure that the hydraulic device should provide in order to generate the second braking force on the rear axle; determining the minimum hydraulic pressure between the first hydraulic pressure and the second hydraulic pressure as the first target hydraulic pressure; determining a hydraulic braking force generated by a second shaft of the front shaft and the rear shaft when the hydraulic device provides the first target hydraulic pressure to the second shaft; A difference between the braking force to be distributed to the second shaft in the total braking force and the hydraulic braking force generated by the second shaft is determined as a target electric braking force to be provided by the motor device to the second shaft.

12. The device according to claim 11, characterized in that The control module is further configured to: If the maximum electric braking force that the motor device can provide to the second shaft is greater than or equal to the target electric braking force, the hydraulic device in the vehicle is controlled to provide the first target hydraulic pressure to the front and rear axles, and the motor device in the vehicle is controlled to provide the target electric braking force to the second shaft.

13. The device according to claim 12, characterized in that If the maximum electric braking force that the motor device can provide to the second shaft is less than the target electric braking force, the control module is further configured to: determining a second target hydraulic pressure, wherein a third sum of a third hydraulic braking force generated on the front axle by the second target hydraulic pressure and a fourth hydraulic braking force generated on the rear axle by the second target hydraulic pressure is equal to a difference between the total braking force and the maximum electric braking force; A hydraulic device in the vehicle is controlled to provide the second target hydraulic pressure to the front and rear axles, and an electric motor device in the vehicle is controlled to provide the maximum electric braking force to the second axle.

14. The device according to any one of claims 9 to 13, characterized in that The control module is further configured to: When preset conditions are met, the hydraulic device in the vehicle is controlled to provide a first target hydraulic pressure for the front axle and the rear axle according to the total braking force, and the motor device in the vehicle is controlled to provide a first electric braking force for the front axle and a second electric braking force for the rear axle. The preset conditions include: the rate of change of the brake pedal in the vehicle is greater than a preset first threshold, the opening of the brake pedal is greater than a preset second threshold, and the slip rate of the vehicle is greater than a preset third threshold.

15. The device according to any one of claims 9 to 13, characterized in that The control module is further configured to: obtaining mode setting information in the vehicle, the mode setting information including first mode information and / or second mode information, the first mode information indicating that, when the total braking force remains unchanged, a ratio of the braking force of the front axle to the braking force of the rear axle is equal to a ratio of the first vertical load to the second vertical load, and the second mode information indicating that, when the total braking force remains unchanged, the electric motor device provides maximum electric braking force to the rear axle; When the mode setting information is the first mode information and the vehicle does not meet the preset conditions, the hydraulic device in the vehicle is controlled to provide the first target hydraulic pressure for the front axle and the rear axle according to the total braking force, and the motor device in the vehicle is controlled to provide the first electric braking force for the front axle and the second electric braking force for the rear axle. The preset conditions include any one or more of the following conditions: the rate of change of the brake pedal in the vehicle is greater than a preset first threshold, the opening of the brake pedal is greater than a preset second threshold, and the slip rate of the vehicle is greater than a preset third threshold.

16. The device according to claim 15, characterized in that When the mode setting information is the second mode information, the control module is further configured to: determining a maximum electric braking force that the electric motor assembly can provide to the rear axle; determining a third target hydraulic pressure, wherein a fourth sum of a fifth hydraulic braking force generated at the front axle by the third target hydraulic pressure and a sixth hydraulic braking force generated at the rear axle by the third target hydraulic pressure is equal to a difference between the total braking force and a maximum electric braking force that can be provided to the rear axle; A hydraulic device in the vehicle is controlled to provide a third target hydraulic pressure to the front and rear axles, and the maximum electric braking force is provided to the rear axle via the motor device.

17. A braking device for a vehicle, characterized in that: include: memory and processor; The memory is used to store program instructions; The processor is configured to call program instructions in the memory to execute the method according to any one of claims 1 to 8.

18. A vehicle, characterized in that: Comprising the apparatus of any one of claims 9 to 16.

19. A computer-readable medium, characterized in that The computer-readable medium stores a program code for computer execution, the program code including instructions for executing the method according to any one of claims 1 to 8.

20. A computer program product, comprising computer program code, characterized in that: When the computer program code is run on a computer, the computer is caused to implement the method according to any one of claims 1 to 8.

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