Vehicle braking method and device

Abstract

This application provides a vehicle braking method and apparatus. In the technical solution provided in this application, the hydraulic efficiency gear in the vehicle is controlled to provide a first target hydraulic pressure to the front axle and the rear axle, and the motor device in the vehicle is controlled to provide a first electric braking force to the front axle and a second electric braking force to the rear axle. The sum of the first hydraulic braking force generated by the first target hydraulic pressure for the front axle, the second hydraulic braking force generated by the first target hydraulic pressure for the rear axle, the first electric braking force, and the second electric braking force is equal to the total braking force required to brake the vehicle. 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. The technical solution provided in this application helps to improve the stability of the vehicle during braking.

Description

Technical Field

[0001] This application relates to the field of automotive technology, and more particularly, to vehicle braking methods and devices.

Background Art

[0002] Vehicle braking means to forcibly decelerate or even stop a moving vehicle based on the requirements of the driver or controller. Hydraulic braking is a form of vehicle braking.

[0003] Currently, when a vehicle realizes braking through hydraulic pressure, the braking process of the vehicle is as follows. After the driver steps on the brake pedal, the total braking force required to brake the vehicle is determined, and then, based on the friction coefficients of the front axle and 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 hydraulic pressure is provided to the front axle and the rear axle of the vehicle for braking.

[0004] However, in the above method for realizing 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, instability may occur in the vehicle during braking.

Summary of the Invention

[0005] This application provides a vehicle braking method and device to help avoid instability during vehicle braking.

[0006] According to the first aspect, this application provides a vehicle braking method including: a step of obtaining a total braking force, where the total braking force is the braking force required to brake the vehicle; and a step of controlling a hydraulic efficiency gear in the vehicle to provide a first target hydraulic pressure to a front axle and a rear axle based on 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. The sum of a first hydraulic braking force generated by the first target hydraulic pressure for the front axle, a second hydraulic braking force generated by the first target hydraulic pressure for the rear axle, the first electric braking force, and the second electric braking force is equal to the total braking force. The 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 the ratio of a first vertical load of the front axle of the vehicle to a second vertical load of the rear axle of the vehicle.

[0007] In the vehicle braking method provided in this application, after obtaining the total braking force required to brake the vehicle, in addition to using the hydraulic efficiency gear to provide braking force to the front axle and the rear axle by providing a first target hydraulic pressure, the motor device is further used to provide braking force to the front axle and the rear axle respectively.

[0008] In other words, in this embodiment, the braking force provided to the front axle is the sum of the braking force provided by the first target hydraulic pressure to the front axle and the braking force provided by the motor device to the front axle, and the braking force provided to the rear axle is the sum of the braking force provided by the first target hydraulic pressure to the rear axle and the braking force provided by the motor device to the rear axle.

[0009] Furthermore, 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. Therefore, the braking method in 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 the instability of the vehicle during braking, that is, the stability of the vehicle during braking is improved.

[0010] Referring to the first aspect, in a possible implementation, the first target hydraulic pressure is the minimum hydraulic pressure among the first hydraulic pressure and the second hydraulic pressure. The first hydraulic pressure is the hydraulic pressure that needs to be provided by the hydraulic efficiency gear to enable the front axle to generate the first braking force. The second hydraulic pressure is the hydraulic pressure that needs to be provided by the hydraulic efficiency gear to enable the rear axle to generate the second braking force. The first braking force and the second braking force are the braking forces that need to be respectively distributed to the front axle and the rear axle when the total braking force is distributed to the front axle and the rear axle based on the first vertical load and the second vertical load. The electric braking force provided by the motor device to the first axle among the front axle and the rear axle is zero, and the first axle is the axle corresponding to the minimum hydraulic pressure.

[0011] Since the minimum hydraulic pressure among the first hydraulic pressure and the second hydraulic pressure can meet the braking force requirement of the axle (also called the first axle) corresponding to the minimum braking force among the first braking force and the second braking force at the front axle and the rear axle, the minimum hydraulic pressure is used as the hydraulic pressure when the hydraulic efficiency gear is used to provide the braking force. The motor device may not need to provide additional braking force to the first axle, that is, it can be understood that the motor device provides zero electric braking force to the first axle. In other words, in this implementation, by only using the motor device, the electric braking force may be provided to the other axle (also called the second axle), and as a result, the ratio of the total braking force (i.e., electric braking force and hydraulic braking force) generated for the second axle by the minimum hydraulic pressure to the braking force generated for the first axle is made to satisfy the ratio of the vertical load of the second axle to the vertical load of the first axle.

[0012] In this embodiment, since only one motor needs to provide electric braking force to one axle, the braking stability of the vehicle can be improved in a simple manner.

[0013] Referring to the first aspect, in a possible implementation, when the total braking force is distributed to the front axle and the rear axle based on the first vertical load and the second vertical load, the method needs to determine a first braking force that needs to be distributed to the front axle and a second braking force that needs to be distributed to the rear axle, determine a first hydraulic pressure that needs to be provided by the hydraulic efficiency gear to enable the front axle to generate the first braking force, determine a second hydraulic pressure that needs to be provided by the hydraulic efficiency gear to enable the rear axle to generate the second braking force, determine the minimum hydraulic pressure among the first hydraulic pressure and the second hydraulic pressure as the first target hydraulic pressure, when the hydraulic efficiency gear provides the first target hydraulic pressure to the second axle among the front axle and the rear axle, determine the hydraulic braking force generated by the second axle, and further include determining the difference between the braking force that needs to be distributed to the second axle among the total braking force and the hydraulic braking force generated by the second axle as the target electric braking force that the motor device needs to provide to the second axle.

[0014] Optionally, in this application, the step of controlling the hydraulic efficiency gear in the vehicle to provide the first target hydraulic pressure to the front axle and the rear axle, and controlling 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 includes, when the maximum electric braking force that the motor device can provide to the second axle is greater than or equal to the target electric braking force, controlling the hydraulic efficiency gear in the vehicle to provide the first target hydraulic pressure to the front axle and the rear axle, and controlling the motor device in the vehicle to provide the target electric braking force to the second axle.

[0015] In this implementation, after the minimum hydraulic pressure among the first hydraulic pressure and the second hydraulic pressure is determined as the first target hydraulic pressure, by using the motor device, the target braking force is compensated to the second axle as the difference between the braking force that needs to be distributed to the second axle and the hydraulic braking force generated by the second axle with the minimum hydraulic pressure. Therefore, it can be ensured that the total braking force remains unchanged when vehicle braking is executed, and it can be ensured that the vehicle can brake based on the requirements.

[0016] Referring to the first aspect, in a possible implementation, when the maximum electric braking force that the motor device can provide to the second axle is smaller than the target electric braking force, the method includes a step of determining a second target hydraulic pressure, where the third sum of the third hydraulic braking force generated by the second target hydraulic pressure for the front axle and the fourth hydraulic braking force generated by the second target hydraulic pressure for the rear axle is equal to the difference between the total braking force and the maximum electric braking force; and a step of controlling a hydraulic efficiency gear in the vehicle to provide the second target hydraulic pressure to the front axle and the rear axle, and controlling a motor device in the vehicle to provide the maximum electric braking force to the second axle.

[0017] It should be understood that there may also be a case where the maximum braking force that the motor device can provide to the second axle is smaller than the braking force that the motor device needs to compensate for the second axle. In this embodiment, when the maximum braking force that the motor device can provide to the second axle is smaller than the braking force that the motor device needs to compensate for the second axle, the motor device is controlled to provide the maximum braking force to the second axle, and then the remaining braking force (the difference between the total braking force and the maximum braking force provided to the second axle) is compensated through hydraulic braking to ensure that the total braking force remains unchanged and realize the braking of the vehicle.

[0018] Referring to the first aspect, in a possible implementation, the step of controlling a hydraulic efficiency gear in the vehicle to provide a first target hydraulic pressure to the front axle and the rear axle based on 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 includes, when a preset condition is satisfied, controlling the hydraulic efficiency gear in the vehicle to provide the first target hydraulic pressure to the front axle and the rear axle based on the total braking force, and controlling 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. The preset conditions include that the change rate of the brake pedal in the vehicle is greater than a preset first threshold, the opening degree 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.

[0019] When the change rate of the brake pedal in the vehicle is greater than a preset first threshold, or when the opening of the brake pedal is greater than a preset second threshold, or when the slip rate of the vehicle is greater than a preset third threshold, it should be understood that this may indicate that the current requirement for braking is stronger. Further, this may reflect that the degree of emergency braking is deeper and it is necessary to ensure the stability of the vehicle during braking. Therefore, in this embodiment, when the change rate of the brake pedal in the vehicle is greater than a preset first threshold, or the opening of the brake pedal is greater than a preset second threshold, or the slip rate of the vehicle is greater than a preset third threshold, the braking method in the first aspect of this application is executed to help avoid the instability of the vehicle during braking.

[0020] Referring to the first aspect, in a possible implementation manner, based on the total braking force, the step of controlling the hydraulic efficiency gear in the vehicle to provide a first target hydraulic pressure to the front axle and the rear axle, 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 is the step of obtaining mode setting information in the vehicle, where the mode setting information includes first mode information and / or second mode information, the first mode information indicates 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 indicates that when the total braking force remains unchanged, the motor device can provide the 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, based on the total braking force, control the hydraulic efficiency gear in the vehicle to provide the first target hydraulic pressure to the front axle and the rear axle, and control 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. The preset conditions include any one or more of the following conditions, that is, the change rate of the brake pedal in the vehicle is greater than the preset first threshold, the opening degree of the brake pedal is greater than the preset second threshold, and the slip rate of the vehicle is greater than the preset third threshold. The step includes the steps mentioned above.

[0021] In this implementation manner, the mode setting information in the vehicle may be used to trigger the execution of the braking method according to the first aspect of this application. In this implementation manner, the driver's requirements may be met, and as a result, it can be understood that the driver has a good sense of experience.

[0022] Referring to the first aspect, in a possible implementation manner, when the mode setting information is the second mode information, the method includes determining the maximum electric braking force that can be provided by the motor device to the rear axle, and determining the third target hydraulic pressure. The fourth sum of the fifth hydraulic braking force generated by the third target hydraulic pressure for the front axle and the sixth hydraulic braking force generated by the third target hydraulic pressure for 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. The step includes the steps mentioned above. The method further includes controlling the hydraulic efficiency gear in the vehicle to provide the third target hydraulic pressure to the front axle and the rear axle, and providing the maximum electric braking force to the rear axle through the motor device.

[0023] In this implementation manner, the motor device can provide the maximum electric braking force to the rear axle, and the remaining braking force is compensated through hydraulic pressure, so that the driver can feel more comfortable during braking.

[0024] According to a second aspect, this application provides a vehicle braking device. The device may include a module configured to implement the braking method in the implementation manner of the first aspect. Optionally, each module may be implemented by using hardware and / or software.

[0025] For example, the braking device may include an acquisition module configured to acquire the total braking force, where the total braking force is the braking force required to brake the vehicle, and a control module configured to control a hydraulic efficiency gear in the vehicle to provide a first target hydraulic pressure to the front axle and the rear axle based on the total braking force, control a motor device in the vehicle to provide a first electric braking force to the front axle, and provide a second electric braking force to the rear axle. The sum of the first hydraulic braking force generated by the first target hydraulic pressure for the front axle, the second hydraulic braking force generated by the first target hydraulic pressure for the rear axle, the first electric braking force, and the second electric braking force is equal to the total braking force. 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.

[0026] In a possible implementation manner, 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 needs to be provided by the hydraulic efficiency gear to enable the front axle to generate the first braking force, and the second hydraulic pressure is the hydraulic pressure that needs to be provided by the hydraulic efficiency gear to enable the rear axle to generate the second braking force. The first braking force and the second braking force are the braking forces that need to be distributed to the front axle and the rear axle respectively when the total braking force is distributed to the front axle and the rear axle based on the first vertical load and the second vertical load. 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.

[0027] In a possible implementation manner, when the total braking force is distributed to the front axle and the rear axle based on the first vertical load and the second vertical load, the control module determines the first braking force that needs to be distributed to the front axle and the second braking force that needs to be distributed to the rear axle, determines the first hydraulic pressure that needs to be provided by the hydraulic efficiency gear to enable the front axle to generate the first braking force, determines the second hydraulic pressure that needs to be provided by the hydraulic efficiency gear to enable the rear axle to generate the second braking force, determines the minimum hydraulic pressure among the first hydraulic pressure and the second hydraulic pressure as the first target hydraulic pressure, when the hydraulic efficiency gear provides the first target hydraulic pressure to the second axle among the front axle and the rear axle, determines the hydraulic braking force generated by the second axle, and is further configured to determine the difference between the braking force that needs to be distributed to the second axle among the total braking force and the hydraulic braking force generated by the second axle as the target electric braking force that the motor device needs to provide to the second axle.

[0028] In a possible implementation manner, when the maximum electric braking force that the motor device can provide to the second axle is greater than or equal to the target electric braking force, the control module is further configured to control the hydraulic efficiency gear in the vehicle to provide the first target hydraulic pressure to the front axle and the rear axle, and control the motor device in the vehicle to provide the target electric braking force to the second axle.

[0029] In a possible implementation manner, when 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 further configured to determine the second target hydraulic pressure, the third sum of the third hydraulic braking force generated by the second target hydraulic pressure for the front axle and the fourth hydraulic braking force generated by the second target hydraulic pressure for the rear axle is equal to the difference between the total braking force and the maximum electric braking force, control the hydraulic efficiency gear 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.

[0030] In a possible implementation manner, when a preset condition is satisfied, the control module controls the hydraulic efficiency gear in the vehicle to provide a first target hydraulic pressure to the front axle and the rear axle based on the total braking force, and further configures to 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 includes that the change rate of the brake pedal in the vehicle is greater than a preset first threshold, the opening degree 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.

[0031] In a possible implementation manner, the control module is further configured to obtain mode setting information in the vehicle. The mode setting information includes first mode information and / or second mode information. The first mode information indicates 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. The second mode information indicates that when the total braking force remains unchanged, the motor device can provide the maximum electric braking force to the rear axle. When the mode setting information is the first mode information and the vehicle does not satisfy the preset condition, based on the total braking force, the control module is further configured to control the hydraulic efficiency gear in the vehicle to provide a first target hydraulic pressure to the front axle and the rear axle, 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 includes any one or more of the following conditions, that is, the change rate of the brake pedal in the vehicle is greater than a preset first threshold, the opening degree 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 a possible implementation manner, when the mode setting information is the second mode information, the control module is further configured to determine the maximum electric braking force that can be provided by the motor device to the rear axle and determine a third target hydraulic pressure, and the fourth sum of the fifth hydraulic braking force generated by the third target hydraulic pressure for the front axle and the sixth hydraulic braking force generated by the third target hydraulic pressure for 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, and control the hydraulic efficiency gear in the vehicle to provide the third target hydraulic pressure to the front axle and the rear axle, and is further configured to provide the maximum electric braking force to the rear axle through the motor device.

[0033] According to a third aspect, this application provides a vehicle braking device including a memory and a processor. The memory is configured to store program instructions, and the processor is configured to call the program instructions in the memory and execute a method according to any one of the first aspect or possible implementation manners of the first aspect.

[0034] According to a fourth aspect, this application provides a vehicle including a device according to any one of the second aspect or possible implementation manners of the second aspect.

[0035] According to a fifth aspect, this application provides a computer-readable medium. The computer-readable medium stores program code used to be executed by a computer, and the program code includes instructions used to execute a method according to any one of the first aspect or possible implementation manners of the first aspect.

[0036] According to a sixth aspect, this application provides a computer program product. The computer program product includes computer program code. When the computer program code is executed on a computer, the computer can be enabled to implement a method according to any one of the first aspect or possible implementation manners of the first aspect.

[0037] In this application, for the technical effect of any one of the second to sixth aspects, refer to the first aspect. Details will not be described again here.

Brief Description of the Drawings

[0038]

Figure 1

Figure 2

Figure 3

Figure 4

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Figure 10

Modes for Carrying Out the Invention

[0039] A green car is a type of automobile that is growing rapidly today, and its braking is directly related to traffic safety. Vehicle braking also means forcibly decelerating or even stopping a moving vehicle based on the requirements of the driver or controller.

[0040] Figure 1 is a diagram showing the structure of a braking system in an automobile according to this application. As shown in Figure 1, the braking system 100 includes a brake pedal 101, a controller 102, a hydraulic braking device 103, a motor braking device 104, and a wheel 105.

[0041] Regarding the braking system 100 shown in Figure 1, when the driver steps on the brake pedal 101, the braking mainly includes two paths, namely, hydraulic braking and motor braking. Specifically, for hydraulic braking, when the driver steps on the brake pedal 101, the controller 102 transmits the braking force generated by the driver stepping on the brake pedal 101 to the hydraulic braking device 103, and then, based on the control of the hydraulic pressure by the brake master cylinder, hydraulic pipes, brake calipers, etc. in the hydraulic braking device 102, a braking force is applied to the wheel 105 to achieve the braking of the vehicle. For motor braking, when the driver steps on the brake pedal 101, the controller 102 controls the drive motor in the motor braking device 104 to generate reverse torque, and the reverse torque directly acts on the wheel 105 by using transmission components to achieve braking.

[0042] Regardless of whether it is hydraulic braking or motor braking, when reverse torque acts on the wheel to achieve braking, it is necessary to determine the ratio of the braking force distributed to the front axle of the vehicle to the braking force distributed to the rear axle of the vehicle, and it should be noted that this ratio is also referred to as the ratio of the braking force distribution between the front axle and the rear axle in this application.

[0043] More specifically, regarding the braking system 100 shown in Figure 1, when the vehicle achieves braking through hydraulic pressure, as shown in Figure 2, the braking process of the vehicle is as follows. When the driver steps on the brake pedal, the total braking force required to brake the vehicle is determined, and then, based on the friction coefficients of the front axle and 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, and the braking force F of the front axle x1 and the braking force F of the rear axle x2They are generated separately to achieve vehicle braking.

[0044] Furthermore, when the current vehicle uses hydraulic pressure to achieve braking, since the friction coefficients of the front axle and the rear axle are fixed, when the vehicle actually performs braking, the ratio of the braking force of the front axle generated to the braking force of the rear axle is usually a fixed value. In other words, when the vehicle uses hydraulic pressure to achieve braking, the ratio of the actual braking force of the front axle generated to the braking force of the rear axle is a fixed value.

[0045] Actually, when the vehicle brakes by using the hydraulic braking method, the distribution of the braking force of the front axle and the braking force of the rear axle should satisfy curve I. Each point on curve I represents the braking force that needs to be distributed to the front axle and the braking force that needs to be distributed to the rear axle under the corresponding total braking force. That is, the distribution of the braking force of the front axle and the braking force of the rear axle corresponding to any point on curve I is optimal. For the related concepts of curve I, refer to the detailed description in the prior art. Details will not be described again here.

[0046] For example, FIG. 3 is a schematic diagram of the distribution of braking forces of the front axle and the rear axle according to an embodiment of this application. As shown in FIG. 3, the horizontal axis represents the braking force of the front axle (unit value: kN), and the vertical axis represents the braking force of the rear axle (unit value: kN). The ideal optimal distribution of the braking force of the front axle and the braking force of the rear axle during vehicle braking should satisfy curve I, and the braking force of the front axle actually generated during vehicle braking and the braking force of the rear axle actually generated should satisfy line β. From the comparison, after the friction coefficient of the front axle and the friction coefficient of the rear axle of the vehicle are fixed, except that the distribution of the braking force of the front axle and the braking force of the rear axle of the vehicle under specific operating conditions satisfies curve I (that is, the distribution of the braking force of the front axle and the braking force of the rear axle at the intersection of curve I and line β in FIG. 3), the distribution of the braking force of the front axle and the braking force of the rear axle is not ideal under most other operating conditions, and it can be seen that there is a specific difference from curve I. Therefore, under the distribution conditions of the braking force of the front axle actually generated corresponding to line β and the braking force of the rear axle actually generated, there may be a situation where the rear wheels of the vehicle lock and skid first, and then the front wheels lock and skid, that is, instability of the braking vehicle occurs.

[0047] Furthermore, the distribution of the braking force of the front axle and the braking force of the rear axle not only affects the stability of the vehicle, but also affects the comfort of the braking vehicle and the energy recovery efficiency during braking.

[0048] In consideration of this, an embodiment of this application provides a vehicle braking method for distributing the braking force of the front axle and the braking force of the rear axle of a vehicle in a hybrid manner of hydraulic braking and motor braking. Therefore, the stability of the braking vehicle can be realized, and furthermore, the comfort of the braking vehicle and the energy recovery efficiency during braking can be improved. The method can be executed in a brake controller or a vehicle controller. For example, FIG. 4 is a schematic diagram of a braking system when a vehicle according to this application brakes. As shown in FIG. 4, system 400 includes a vehicle state measurement and estimation module 401, a brake controller or vehicle controller 402, a sensing module 403, a motor device 404, and a hydraulic efficiency gear 405.

[0049] The vehicle state measurement and estimation module 401 is configured to measure and estimate vehicle states such as the longitudinal and lateral accelerations of the vehicle, the road surface gradient, and the wheel speeds, which are necessary to realize the function of distributing the braking force of the front axle and the braking force of the rear axle.

[0050] The brake controller or vehicle controller 402 is configured to determine the total braking force when the vehicle brakes, execute the vehicle braking method provided in this application, and control the motor device 404 and the hydraulic efficiency gear 405 to distribute the braking force of the front axle and the braking force of the rear axle.

[0051] The sensing module 403 is configured to sense the driving intention of the driver or the autonomous driving. The driving intention in this application mainly refers to the intention that the driver or the autonomous driving vehicle needs to execute vehicle braking.

[0052] The motor device 404 executes the braking force of the front axle and / or the braking force of the rear axle that needs to be distributed by the motor based on the calculation from the brake controller or vehicle controller 402. It should be noted that the specific form of the motor device 404 is not limited in this embodiment of this application. For example, the device may be a single motor mechanism, a two-motor mechanism, a three-motor mechanism, or a four-motor mechanism.

[0053] The hydraulic efficiency gear 405 executes the braking force of the front axle and / or the braking force of the rear axle that needs to be distributed by the hydraulic efficiency gear 405 based on the calculation from the brake controller or vehicle controller 402.

[0054] It should be noted that this embodiment of this application may be applied to an artificial intelligence driving scenario, or may be extended to an autonomous driving scenario or a manual driving scenario.

[0055] Figure 5 shows a vehicle braking method according to an embodiment of this application. As shown in Figure 5, the method includes S501 and S502. The method in this application may be executed by the braking system shown in Figure 4.

[0056] S501: Obtain the total braking force, which is the braking force required to brake the vehicle.

[0057] Braking means to forcibly decelerate or even stop a moving vehicle based on the request of the driver or controller. In this embodiment, the total braking force is the value of the braking force required for the vehicle to achieve braking. For example, the value of the total braking force of the vehicle from the running state to the stopped state is realized.

[0058] It should be noted here that the method of obtaining the total braking force is not limited in the embodiments of this application.

[0059] In a realization solution, when the vehicle is manually driven, the total braking force may be determined based on the state of the brake pedal depressed by the driver. For example, the total braking force is determined based on the opening of the brake pedal. It should be understood that when the opening of the brake pedal is different, the total braking force required for the vehicle to achieve braking is also different.

[0060] In another implementation solution, when the vehicle is automatically driven, the currently required total braking force may be determined by using some road condition information collected by the autonomous vehicle. For example, based on the collected information, if it is determined that there is a red light at the intersection ahead and the current vehicle speed is too high, the vehicle automatically determines the value of the currently required total braking force.

[0061] S502: Based on the total braking force, control the hydraulic efficiency gear in the vehicle to provide a first target hydraulic pressure to the front axle and the rear axle, 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 sum of the first hydraulic braking force generated by the first target hydraulic pressure for the front axle, the second hydraulic braking force generated by the first target hydraulic pressure for 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.

[0062] The vertical load of the front axle may be considered as the acting force of the vehicle acting vertically on the front axle, and the vertical load of the rear axle may be considered as the acting force of the vehicle acting vertically on the rear axle.

[0063] The vertical load of the front axle (also referred to as the first vertical load in this application) and the vertical load of the rear axle (also referred to as the second vertical load in this application) are important factors affecting the distribution of the braking force of the front axle and the rear axle. It should be noted that the vertical load is affected by the braking acceleration of the vehicle during braking. For example, during emergency braking, the vehicle may cause a serious axle weight transfer due to inertia, that is, the vertical load of the front axle increases and the vertical load of the rear axle decreases. Therefore, the axle weight transfer caused during braking also affects the distribution of the braking force of the front axle and the rear axle by using the vertical load.

[0064] Generally, when the vertical load of the front axle and the vertical load of the rear axle are determined and the total braking force is determined, the braking force that needs to be distributed to the front axle and the braking force that needs to be distributed to the rear axle may be determined. Specifically, the ratio of the braking force of the front axle to the braking force of the rear axle is the ratio of the vertical load of the front axle to the vertical load of the rear axle. In this application, the braking force that needs to be distributed to the front axle is also referred to as the first braking force, and the braking force that needs to be distributed to the rear axle is also referred to as the second braking force.

[0065] Here, it should be noted that the braking force that needs to be distributed to the front axle and the braking force that needs to be distributed to the rear axle are the braking forces of the front axle and the rear axle on curve I. In other words, when providing braking force to the front axle and the rear axle in this application, if 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, the braking forces of the front axle and the rear axle are on curve I, and as a result, the stability of the vehicle during braking can be ensured.

[0066] However, when hydraulic braking is used, it should be understood that the hydraulic pressure provided by the hydraulic braking device to the front axle is the same as the hydraulic pressure provided to the rear axle. This is because the friction coefficient of the front axle does not match the friction coefficient of the rear axle. As a result, 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 is different from the braking force generated by the rear axle. Therefore, it can be understood that in most operating conditions, when only the braking forces of the front axle and the rear axle provided by the hydraulic brake are used, the ratio of the braking force of the front axle to the braking force of the rear axle is not the ratio of the vertical load of the front axle to the vertical load of the rear axle. In view of this, in this embodiment, the hydraulic braking method and the motor braking method are used in combination to brake the vehicle. As a result, the sum (also called the first sum) of the braking force generated by the hydraulic pressure acting on the front axle and the braking force provided by the motor device to the front axle is the first braking force, and the sum (also called the second sum) of the braking force generated by the hydraulic pressure acting on the rear axle and the braking force generated by the motor device on the rear axle is the second braking force. Specifically, the vehicle is braked by using both the hydraulic braking method and the motor braking method. As a result, 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, and the braking forces of the front axle and the rear axle are on curve I to ensure the stability of the vehicle during braking.

[0067] In one example, in this embodiment, after the hydraulic pressure (also referred to as the first target hydraulic pressure) is determined, the braking force generated by the first target hydraulic pressure on the front axle (also referred to as the first hydraulic braking force) and the braking force generated on the rear axle (also referred to as the second hydraulic braking force) may be calculated first. Then, the difference between the first braking force and the first hydraulic braking force (for example, the obtained difference is referred to as the front axle electric braking force compensation value) is calculated to obtain the electric braking force (also referred to as the first electric braking force) that the motor device needs to provide to the front axle. The difference between the second braking force and the second hydraulic braking force (for example, the obtained difference is referred to as the rear axle electric braking force compensation value) is calculated to obtain the electric braking force (also referred to as the second electric braking force) that the motor device needs to provide to the rear axle. Finally, when braking, the first target hydraulic pressure is provided to the front axle and the rear axle, 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 through the motor device.

[0068] In the vehicle braking method provided in this application, after the total braking force required to brake the vehicle is obtained, in addition to using a hydraulic efficiency gear to provide braking force to the front axle and the rear axle by providing a first target hydraulic pressure, the motor device is further used to provide braking force to the front axle and the rear axle respectively. In other words, 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. Further, 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. Therefore, the braking force of the front axle and the braking force of the rear axle determined based on the braking method in this embodiment are located on curve I, which helps to avoid the instability of the vehicle during braking.

[0069] In the implementation solution, the first target hydraulic pressure in this application is the minimum hydraulic pressure among the first hydraulic pressure and the second hydraulic pressure. The first hydraulic pressure is the hydraulic pressure that needs to be provided by the hydraulic efficiency gear when the front axle generates the first braking force, and the second hydraulic pressure is the hydraulic pressure that needs to be provided by the hydraulic efficiency gear when the rear axle generates the second braking force. The first braking force and the second braking force are the braking forces that need to be distributed to the front axle and the rear axle respectively when the total braking force is distributed to the front axle and the rear axle based on the first vertical load and the second vertical load. In this solution, the electric braking force provided by the motor device to the first axle among the front axle and the rear axle is zero, and the first axle is the axle corresponding to the minimum hydraulic pressure.

[0070] For the sake of easy understanding, the braking method in this implementation solution will be described in detail with reference to FIG. 6. The method includes the following steps.

[0071] S601: Obtain the total braking force, which is the braking force required to brake the vehicle.

[0072] For the detailed description of this step, refer to the description of S501 in the embodiment of FIG. 5. Details will not be described again here.

[0073] S602: Based on the vertical load of the front axle of the vehicle and the vertical load of the rear axle of the vehicle, determine the first braking force that needs to be distributed to the front axle and the second braking force that needs to be distributed to the rear axle.

[0074] In a specific implementation manner, when the total braking force is represented as f b the vertical load of the front axle during braking is represented as f z1 the vertical load of the rear axle during braking is represented as f z2 the braking force that needs to be distributed to the front axle (i.e., the first braking force) is represented as f b1 and the braking force that needs to be distributed to the rear axle (i.e., the second braking force) is represented as f b2 the following holds:

Equation

[0075] Here, it should be noted that the first braking force and the second braking force calculated in this way correspond to the points on curve I. Specifically, the braking force to be distributed to the front axle and the braking force to be distributed to the rear axle, which are calculated by using the vertical load of the front axle and the vertical load of the rear axle respectively, are the optimal distribution.

[0076] S603: Determine the first hydraulic pressure based on the first braking force, determine the second hydraulic pressure based on the second braking force, the first hydraulic pressure is the hydraulic pressure required to realize the first braking force of the front axle, and the second hydraulic pressure is the hydraulic pressure required to realize the second braking force of the rear axle.

[0077] When hydraulic braking is used, it should be understood that the braking force distributed to the front axle or the braking force distributed to the rear axle is realized by controlling the hydraulic pressure. In other words, when the hydraulic pressure is different, the braking force distributed to the front axle is different from the braking force distributed to the rear axle.

[0078] Therefore, in this embodiment, after the first braking force to be distributed to the front axle and the second braking force to be distributed to the rear axle are determined separately, the hydraulic pressure required to realize the first braking force of the front axle (also called the first hydraulic pressure) and the hydraulic pressure required to realize the second braking force of the rear axle (also called the second hydraulic pressure) are further determined.

[0079] In a specific implementation manner, when the first hydraulic pressure is represented as p1 and the second hydraulic pressure is represented as p2,

Equation

[0080] Here, c1 represents the friction coefficient of the front axle, and c2 is 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, refer to the description in the prior art. Details will not be described again here.

[0081] S604: Determine the minimum of the first hydraulic pressure and the second hydraulic pressure as the first target hydraulic pressure, and when the hydraulic efficiency gear provides the first target hydraulic pressure to the second axle of the front axle and the rear axle, determine the hydraulic braking force generated by the second axle.

[0082] When hydraulic braking is used, it should be noted that the hydraulic pressure provided by the hydraulic braking device to the front axle is the same as the hydraulic pressure provided to the rear axle. However, since the friction coefficient of the front axle does not match the friction coefficient of the rear axle, as a result, 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 is different from the braking force generated by the rear axle.

[0083] Specifically, when hydraulic braking is used, if the hydraulic pressure provided by the hydraulic braking device is recorded as p, 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.

[0084] S605: Determine the difference between the braking force that needs to be distributed to the second axle among the total braking force and the hydraulic braking force generated by the second axle as the target electric braking force that the motor device needs to provide to the second axle.

[0085] It can be understood that when the minimum hydraulic pressure is used as the hydraulic pressure provided when hydraulic braking is used, the braking force of the axle corresponding to the minimum hydraulic pressure may be satisfied. For example, when the first hydraulic pressure is smaller than the second hydraulic pressure, when the first hydraulic pressure is used as the hydraulic pressure provided when hydraulic braking is used, the first braking force of the front axle may be satisfied. When the second hydraulic pressure is smaller than the first hydraulic pressure, when the second hydraulic pressure is used as the hydraulic pressure provided when hydraulic braking is used, the second braking force of the rear axle may be satisfied.

[0086] When the minimum of the first hydraulic pressure and the second hydraulic pressure is used as the hydraulic pressure provided when hydraulic braking is used, for the axle corresponding to the maximum of the first hydraulic pressure and the second hydraulic pressure (also called the second axle in this application), the braking force provided by the minimum hydraulic pressure for the second axle is less than the braking force that needs to be distributed to the second axle when the total braking force is distributed based on the vertical load, that is, it can be further understood that the braking force provided by the minimum hydraulic pressure is not sufficient. In other words, there is a difference between the braking force provided by the minimum hydraulic pressure for the second axle and the ideal braking force of the second axle. In this case, in this embodiment, the first compensated electric braking force (also called the target electric braking force) is determined based on the maximum of the first hydraulic pressure and the second hydraulic pressure, and the target electric braking force is used to make the braking force of the second axle equal to the braking force that needs to be distributed to the second axle when the total braking force is distributed based on the vertical load when the target electric braking force is used to provide the minimum hydraulic pressure to the target axle.

[0087] In one example, the target electric braking force is the braking force difference between the braking force provided by the minimum hydraulic pressure for the second axle and the braking force that needs to be distributed to the second axle when the total braking force is distributed based on the vertical load. The minimum of the first hydraulic pressure and the second hydraulic pressure is represented as p min and the target electric braking force is represented as f compensation when represented as follows,

Equation

[0088] S606: Provide the minimum hydraulic pressure to the vehicle through the hydraulic efficiency gear and provide the target electric braking force to the second axle through the motor device.

[0089] In this embodiment, after the minimum hydraulic pressure and the target electric braking force are determined, and it is determined that the maximum electric braking force that the motor device can provide to the second axle is equal to or greater than the target electric braking force, the hydraulic efficiency gear is used to provide the minimum hydraulic pressure to the vehicle, and the motor device is used to provide the target electric braking force to the second axle to provide the total braking force to the vehicle to achieve braking of the vehicle.

[0090] According to the vehicle braking method provided in this application, after the total braking force required to achieve vehicle braking is obtained, the optimal braking force of the front axle and the optimal braking force of the rear axle are first determined separately based on the vertical load of the front axle and the vertical load of the rear axle. Then, the sum of the optimal hydraulic pressure of the front axle and the optimal hydraulic pressure of the rear axle is determined based on the optimal braking force of the front axle and the optimal braking force of the rear axle. Next, the minimum hydraulic pressure among the optimal hydraulic pressure of the front axle and the optimal hydraulic pressure of the rear axle is used as the hydraulic pressure when the braking force is provided to the vehicle by using the hydraulic efficiency gear. When the braking force is provided to the vehicle by using the minimum hydraulic pressure, it may be ensured that the braking force of the axle corresponding to the minimum hydraulic pressure is optimal. It can be understood that for the braking force of the second axle corresponding to the maximum hydraulic pressure, the braking force provided to the second axle by the minimum hydraulic pressure cannot reach the optimal braking force of the second axle. In this embodiment of this application, in order to enable the braking force of the second axle to reach the optimal braking force of the target axle, the target electric braking force is further provided to the target axle through the motor device. The target electric braking force is the braking force difference between the braking force provided to the second axle by the minimum hydraulic pressure and the braking force that needs to be distributed to the second axle when the total braking force is distributed based on the vertical load. Therefore, the technical solution provided in this application helps to improve the stability of the vehicle during braking.

[0091] It can be understood that there may be cases where the maximum electric braking force provided by the motor device to the second axle is smaller than the target electric braking force. For example, the maximum electric braking force that can be provided by the motor device to the second axle and is defined in the current vehicle state regulation is smaller than the target electric braking force determined in this application, or the upper limit of the electric braking force that can be provided by the motor device to the second axle is smaller than the target electric braking force determined in this application. In this embodiment of this application, when the maximum electric braking force that can be provided by the motor device to the second axle is smaller than the target electric braking force, the method in this application is a step of determining a second target hydraulic pressure, and the third sum of the third hydraulic braking force generated by the second target hydraulic pressure for the front axle and the fourth hydraulic braking force generated by the second target hydraulic pressure for the rear axle is equal to the difference between the total braking force and the maximum electric braking force, and a step of controlling the hydraulic efficiency gear 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 axle.

[0092] In a specific implementation manner, when the maximum electric braking force that the motor device can provide to the second axle is smaller 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 that the motor device provides to the second axle is used, and the remaining braking force is compensated by using hydraulic pressure (also called the second target hydraulic pressure in this application).

[0093] For example, in the implementation solution, the second target hydraulic pressure is the quotient of the first braking force difference and the target friction coefficient. The first braking force difference is the difference between the total braking force and the maximum electric braking force that can be provided by the motor device to the second axle, and the target friction coefficient is the sum of the friction coefficients of the front wheels and the rear wheels. For example, if the maximum electric braking force provided by the motor device to the second axle is represented as f electric-max and the second target hydraulic pressure is represented as p compensation in this case, the first braking force difference may be represented as f b -f electric-max Furthermore,

Number

[0094] Alternatively, p compensation may be calculated by using the following formula.

Equation

[0095] f compensation For the concepts of c1 and c2, refer to the description in the above embodiments. Details are not described again here.

[0096] In this embodiment, when the maximum electric braking force that the motor device can provide to the second axle is smaller than the target electric braking force, in addition to the maximum electric braking force that the motor device provides to the second axle, the remaining insufficient braking force is all compensated by using hydraulic pressure, and as a result, the actual braking force of the vehicle is made to match the total braking force, and as a result, the vehicle realizes braking.

[0097] In an optional embodiment, in this application, based on the total braking force, controlling the hydraulic efficiency gear in the vehicle to provide a first target hydraulic pressure to the front axle and the rear axle, 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 may be executed only when a preset condition is satisfied. For example, the preset conditions include that the change rate of the brake pedal in the vehicle is greater than a preset first threshold, the opening degree 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. In other words, the process of S502 in this application is executed only when the change rate of the brake pedal in the vehicle is greater than a preset first threshold, or the opening degree of the brake pedal is greater than a preset second threshold, or the slip rate of the vehicle is greater than a preset third threshold.

[0098] Here, it should be noted that the specific values of the first threshold, the second threshold, and the third threshold are not limited in this embodiment and may be determined based on different requirements.

[0099] In an optional embodiment, in this application, the mode setting information in the vehicle may alternatively be acquired first. The mode setting information includes first mode information and / or second mode information. The first mode information indicates 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. The second mode information indicates that when the total braking force remains unchanged, the motor device can provide the 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 process of S502 in this application is executed. The preset conditions include any one or more of the following conditions, that is, the change rate of the brake pedal in the vehicle is greater than the preset first threshold, the opening degree of the brake pedal is greater than the preset second threshold, and the slip rate of the vehicle is greater than the preset third threshold.

[0100] 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, and as a result, the stability of the vehicle during braking can be ensured. Therefore, in this application, the first mode information is also called the stable mode.

[0101] It can be understood that when the motor device provides the maximum electric braking force to the rear axle when the total braking force remains unchanged, the driver's comfort can be improved. Therefore, in this embodiment, the second mode information is also called the comfort mode.

[0102] Optionally, in this embodiment, an eco-mode may be further included. The eco-mode means improving the energy recovery efficiency while ensuring that the electric braking force provided by the motor device to the front axle and the electric braking force provided by the rear axle are as large as possible and the overall braking force remains unchanged.

[0103] In other words, in this application, multiple modes may be selected. For example, FIG. 7 is a schematic flowchart of mode selection according to an embodiment of this application. As shown in FIG. 7, the mode selection procedure includes the following steps.

[0104] S701: Obtain the mode set by the vehicle.

[0105] For example, the vehicle may provide a human-computer interaction method for the driver to set the expected mode, or the vehicle may automatically identify the driver's driving style and automatically set the mode expected by the driver.

[0106] S702: Monitor whether the change rate of the brake pedal is greater than a first threshold, or whether the opening of the brake pedal is greater than a preset second threshold, or whether the slip rate of the vehicle is greater than a preset third threshold. If so, S703 is executed; otherwise, S704 is executed.

[0107] S703: Determine that the braking mode of the vehicle is the stable mode.

[0108] In other words, when the monitored change rate of the pedal is greater than the first threshold, or when the opening of the brake pedal is greater than the second threshold, or when the slip rate of the vehicle is greater than the third threshold, it is determined that the braking mode of the vehicle is the stable mode.

[0109] S704: Determine whether the mode set by the vehicle is the stable mode. If so, S703 is executed; otherwise, S705 is executed.

[0110] In other words, when the change rate of the monitored pedal is not greater than the first threshold, the opening degree 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.

[0111] S705: Determine whether the mode set by the vehicle is the eco mode. If so, S706 is executed; otherwise, S707 is executed.

[0112] S706: Determine that the braking mode of the vehicle is the eco mode.

[0113] S707: Determine that the vehicle is in the comfort mode.

[0114] In an optional embodiment, in this application, when the mode setting information is the second mode information (that is, the selected mode is the comfort mode), the method further includes determining the maximum electric braking force that can be provided by the motor device to the rear axle, and determining the third target hydraulic pressure. The fourth sum of the fifth hydraulic braking force generated by the third target hydraulic pressure for the front axle and the sixth hydraulic braking force generated by the third target hydraulic pressure for 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. The method further includes providing the third target hydraulic pressure to the front axle and the rear axle, and controlling the hydraulic efficiency gear in the vehicle to provide the maximum electric braking force to the rear axle through the motor device.

[0115] In other words, in this application, when the selected mode is the comfort mode and it is ensured that the total braking force remains unchanged, the motor device is used as much as possible to achieve the maximum electric braking force on the rear axle, and the hydraulic braking can ensure the system stability as much as possible.

[0116] In a specific implementation manner, the following steps may be included.

[0117] Step 1: Based on the total braking force requirement, the rear axle motor capacity limit, the battery capacity limit, the rear axle vertical force, and the gradient, calculate the maximum electric braking force of the rear axle realized by the motor device. The maximum electric braking force of the rear axle realized by the motor device is f rear-max and is assumed to be expressed as such.

[0118] Step 2: Based on the comparison between the current motor braking force and the total braking force requirement, the excessive braking requirement is realized through hydraulic braking. Specifically, the required hydraulic pressure is p comfort mode compensation and is expressed as such. In this case,

Number

[0119] In this embodiment, when the total braking force remains unchanged, it can be ensured that the maximum braking force is achieved by using the rear axle motor as much as possible, which helps to improve the comfort of the driver during braking.

[0120] In an optional embodiment, in this application, the mode setting information may further include third mode information (i.e., the selected mode is the comfort mode). The third mode information indicates that when the total braking force remains unchanged, in order to improve the energy recovery efficiency, the braking force provided by the motor device to the front axle and the braking force provided by the motor device to the rear axle should be made as large as possible.

[0121] In a specific implementation manner, the following steps may be included.

[0122] Step 1: Based on the vertical load of the front axle of the vehicle and the vertical load of the rear axle of the vehicle, determine the first braking force that needs to be distributed to the front axle and the second braking force that needs to be distributed to the rear axle.

[0123] For example, the total braking force is f b and is expressed as such. The vertical load of the front axle during braking is f z1is expressed as, and the vertical load on the rear axle during braking is f z2 is expressed as, and the first braking force is f b1 is expressed as, and the second braking force is f b2 is expressed as, and in this case,

Number

[0124] Step 2: Based on the first braking force and the second braking force, the motor device distributes the electric braking force of the front axle and the electric braking force of the rear axle.

[0125] Specifically, when the electric braking force of the front axle distributed by the motor device is f electric-front axle is expressed as, and the electric braking force of the rear axle distributed by the motor device is f electric-rear axle is expressed as, the following cases may occur.

[0126] When 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 motor device are not respectively limited by the motor capacity, f electric-front axle = f b1 and f electric-rear axle = f b2 it is.

[0127] When the electric braking force that can be distributed to the front axle by the motor device is limited by the capacity of the motor device, and the electric braking force that can be distributed to the rear axle by the motor device is not limited by the capacity of the motor device, and the maximum value of the electric braking force that can be distributed to the front axle by the motor device is f motor-front axle,max is recorded as, f electric-front axle = f motor-front axle,max and f electric-rear axle = f b - f motor-front axle,max it is.

[0128] The electric braking force that can be distributed to the rear axle by the motor device is limited by the capacity of the motor device, the electric braking force that can be distributed to the front axle by the motor device is not limited by the capacity of the motor device, and the maximum value of the electric braking force that can be distributed to the rear axle by the motor device is f motor-rear axle,max is recorded as, f electric-rear axle = f motor-rear axle,max and f electric-front axle = f b - f motor-rear axle,max is true.

[0129] When both the braking force that can be distributed to the rear axle by the motor device and the braking force that can be distributed to the rear axle are limited by the capacity of the motor device, f electric-front axle = f motor-front axle,max and f electric-rear axle = f motor-rear axle,max is true. Furthermore, in this case, in order to ensure that the total braking force remains unchanged, the remaining braking force is compensated by using hydraulic pressure. Specifically, when the compensated hydraulic pressure is recorded as p economic-hydraulic compensation is recorded as,

Number

[0130] In this embodiment, when the total braking force remains unchanged, it can be ensured that the braking forces of the front axle and the rear axle provided by the motor device become as large as possible, thereby improving the energy recovery efficiency.

[0131] The above describes how to realize the distribution of the front axle braking force and the rear axle braking force in the stable mode, the comfort mode, and the eco mode. When the braking method provided in this application is specifically applied, it should be understood that more attention should be paid to the coordination between the method provided in this application and other braking methods (for example, the method for braking by an anti-lock braking system). The coordination may be considered as the time when the braking method in this application can be activated and the time when the braking method in this application needs to be terminated.

[0132] For example, FIG. 8 is a schematic flowchart for starting and ending a braking method according to an embodiment of this application. As shown in FIG. 8, after the driver steps on the brake pedal or the intelligent driving system sends a brake command for starting, the execution starts based on the process shown in FIG. 8. The detailed process will be described as follows.

[0133] S801: Based on the driver's braking request or by processing the braking request of the intelligent driving system, obtain the total braking force.

[0134] S802: Execute a multi-purpose braking force distribution process.

[0135] The multi-purpose braking force distribution process is the process of distributing the front axle braking force and the rear axle braking force in the stable mode, the process of distributing the front axle braking force and the rear axle braking force in the stable mode, or the process of distributing the front axle braking force and the rear axle braking force in the eco mode, as described in the above embodiments of this application. For the specific process, refer to the above description. Details will not be described again here.

[0136] S803: Determine whether the antilock braking system is activated. If the antilock braking system is activated, S804 is executed, or if the antilock braking system is not activated, S808 is executed.

[0137] S804: Enter the control of the braking method of the antilock braking system.

[0138] The antilock braking system corresponds to a set of braking methods. The braking method may also be considered as a method for distributing the braking force of the front axle and the rear axle.

[0139] S805: Determine whether the braking method of the antilock braking system has ended. If the braking method has ended, S806 is executed, or if the braking method has not ended, S804 continues to be executed.

[0140] S806: Distribute the braking force at a fixed ratio.

[0141] The fixed-ratio distribution is as follows. After the total braking force is determined, the hydraulic pressure required by 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.

[0142] S807: Determine whether the braking request or the vehicle speed is 0. If the braking request or the vehicle speed is 0, end the braking process. Or, if the braking request or the vehicle speed is not 0, continue to execute S806.

[0143] S808: Determine whether the braking request or the vehicle speed is 0. If the braking request or the vehicle speed is not 0, execute S802. Or, if the braking request or the vehicle speed is 0, end the braking process.

[0144] In the above, with reference to FIGS. 5 to 8, the braking method according to the embodiment of this application has been described in detail. Below, with reference to FIGS. 9 and 10, the braking device according to the embodiment of this application will be described in detail.

[0145] FIG. 9 is a schematic diagram of the structure of the braking device according to the embodiment of this application. Specifically, as shown in FIG. 9, the device 900 includes an acquisition module 901 and a control module 902. The device 900 may be configured to implement the method in any of the above-described method embodiments.

[0146] In one example, the acquisition module 901 may be configured to implement S501, and the control module 902 may be configured to implement S502.

[0147] In another example, the acquisition module 901 may be configured to implement S601, and the control module 902 may be configured to implement S602 to S606.

[0148] FIG. 10 is a schematic diagram of the structure of a braking device according to another embodiment of this application. The device shown in FIG. 10 may be configured to execute the method described in any one of the above embodiments.

[0149] As shown in FIG. 10, the device 1000 in 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 communicatively connected to each other through the bus 1004.

[0150] 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 execute the steps of the methods shown in FIGS. 5 to 8.

[0151] The processor 1002 may be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to execute a related program to implement the methods shown in FIGS. 5 to 8 of this application.

[0152] Alternatively, the processor 1002 may be an integrated circuit chip and has signal processing capabilities. In the implementation process, the steps of the methods in FIGS. 5 to 8 in the embodiments of this application may be completed by using the integrated logic circuit of the hardware in the processor 1002 or instructions in the form of software.

[0153] Alternatively, the processor 1002 may 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, discrete gate or transistor logic device, or discrete hardware component. This may implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor may be a microprocessor, or the processor may be any conventional processor or the like.

[0154] The steps of the methods disclosed with reference to the embodiments of this application may be achieved by being directly executed by using a hardware decoding processor, or may be achieved by being executed by using a combination of a hardware module and a software module within the decoding processor. The software module may be located in a well-known storage medium in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, or a register. The storage medium is located in the memory 1001. The processor 1002 reads information from the memory 1001 and, in combination with the hardware of the processor 1002, completes the functions that need to be executed by the units included in the device in this application. For example, the processor 1002 may execute the steps / functions in the embodiments shown in FIGS. 5 to 8.

[0155] The communication interface 1003 may use, but is not limited to, a transceiver-type transceiver device to realize communication between the device 1000 and other devices or communication networks.

[0156] Bus 1004 may include a path for transmitting information among components of apparatus 1000 (e.g., memory 1001, processor 1002, and communication interface 1003).

[0157] It should be understood that the apparatus 1000 shown in this embodiment of this application may be an electronic device or a chip configured within an electronic device.

[0158] All or part of the above embodiments may be implemented using software, hardware, firmware, or any combination thereof. When software is used to implement the embodiments, the above embodiments may be fully or partially implemented 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 programs are loaded and executed on a computer, all or part of the procedures or functions according to the embodiments of this application are generated. The computer may be a general-purpose computer, a dedicated computer, a computer network, or other programmable devices. The computer instructions may 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 may be transmitted in a wired (e.g., infrared, wireless, and microwave, etc.) manner from a website, a computer, a server, or a data center to another website, a computer, a server, or a data center. The computer-readable storage medium may be any usable medium accessible by a computer or a data storage device such as a server or a data center integrating one or more usable media. The usable medium may be a magnetic medium (e.g., a floppy disk, a hard disk, or a magnetic tape), an optical medium (e.g., a DVD), or a semiconductor medium. The semiconductor medium may be a solid-state drive.

[0159] It should be understood that the sequence numbers of the above processes do not imply the execution order in various embodiments of this application. The execution order of the processes should be determined according to the functions and internal logics of the processes and should not be construed as any limitation to the implementation processes of the embodiments of this application.

[0160] Those skilled in the art may recognize that, in combination with the examples described in the embodiments disclosed in this specification, the units and algorithm steps may be implemented by electronic hardware, or by a combination of computer software and electronic hardware. Whether the functions are executed by hardware or by software depends on the specific application and design constraints of the technical solution. Those skilled in the art may use different methods to implement the described functions for each specific application, but the implementation methods should not be considered to exceed the scope of this application.

[0161] For the purpose of convenience and concise description, those skilled in the art can clearly understand that for the detailed operation processes of the above systems, devices and units, reference can be made to the corresponding processes in the embodiments of the above methods. The details will not be described again here.

[0162] In some embodiments provided in this application, it should be understood that the disclosed systems, devices and methods may be implemented in other ways. For example, the described embodiments of the devices are merely examples. For example, the division of units is merely a logical function division, and other divisions may be used in actual implementation methods. For example, multiple units or components may be combined or integrated into other systems, or some features may be ignored or not executed. Furthermore, the disclosed mutual coupling, direct coupling or communication connection may be realized through some interfaces. The indirect coupling or communication connection between devices or units may be realized in electronic, mechanical or other forms.

[0163] A unit described as a separate part may or may not be physically separate. A part displayed as a unit may or may not be a physical unit. It may be located in one place or may be distributed among multiple network units. Some or all of the units may be selected based on actual requirements to achieve the purpose of the solution of the embodiment.

[0164] Furthermore, the functional units in the embodiments of this application may be integrated into one processing unit. Each of the units may exist physically alone, or two or more units may be integrated into one unit.

[0165] When the function is realized in the form of a software functional unit and sold or used as an independent product, the function may be stored in a computer-readable storage medium. Based on such understanding, the technical solution of this application, in essence, or the part that contributes to the prior art or a part of the technical solution may also be realized in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for instructing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method described in the embodiments of this application. The above storage medium includes any medium that can store program codes, such as a USB flash drive, a removable hard disk, a read-only memory, a random access memory, a magnetic disk, or an optical disk.

[0166] The above description is merely a specific implementation manner of this application and is not intended to limit the protection scope of this application. Any modification or substitution that can be easily conceived by those skilled in the art within the technical scope disclosed in this application shall fall within the protection scope of this application. Therefore, the protection scope of this application shall follow the protection scope of the claims.

Claims

1. A vehicle braking method, comprising: obtaining a total braking force, which is a braking force required to brake the vehicle; controlling a hydraulic efficiency gear in the vehicle to provide a first target hydraulic pressure to a front axle and a rear axle based on 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 a first hydraulic braking force generated by the first target hydraulic pressure for the front axle, a second hydraulic braking force generated by the first target hydraulic pressure for 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 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 the ratio of a first vertical load of the front axle of the vehicle to a second vertical load of the rear axle of the vehicle.

2. The first target hydraulic pressure is the minimum of a first hydraulic pressure and a second hydraulic pressure. The first hydraulic pressure is a hydraulic pressure that needs to be provided by the hydraulic efficiency gear to enable the front axle to generate a first braking force, and the second hydraulic pressure is a hydraulic pressure that needs to be provided by the hydraulic efficiency gear to enable the rear axle to generate a second braking force. The first braking force and the second braking force are braking forces that need to be respectively distributed to the front axle and the rear axle when the total braking force is distributed to the front axle and the rear axle based on the first vertical load and the second vertical load. The electric braking force provided by the motor device to a 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. The method according to claim 1.

3. The method further comprises: determining the first braking force that needs to be distributed to the front axle and the second braking force that needs to be distributed to the rear axle when the total braking force is distributed to the front axle and the rear axle based on the first vertical load and the second vertical load; determining the first hydraulic pressure that needs to be provided by the hydraulic efficiency gear to enable the front axle to generate the first braking force; Determining the second hydraulic pressure that needs to be provided by the hydraulic efficiency gear to enable the rear axle to generate the second braking force; Determining the minimum hydraulic pressure among 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 when the hydraulic efficiency gear provides the first target hydraulic pressure to the second axle among the front axle and the rear axle; Determining the difference between the braking force that needs to be distributed to the second axle among the total braking force and the hydraulic braking force generated by the second axle as the target electric braking force that the motor device needs to provide to the second axle; The method according to claim 2, further comprising.

4. Controlling the hydraulic efficiency gear in the vehicle to provide a first target hydraulic pressure to the front axle and the rear axle, 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, the steps are: When the maximum electric braking force that the motor device can provide to the second axle is equal to or greater than the target electric braking force, controlling the hydraulic efficiency gear in the vehicle to provide the first target hydraulic pressure to the front axle and the rear axle, and controlling the motor device in the vehicle to provide the target electric braking force to the second axle, the method according to claim 3, comprising the steps.

5. When the maximum electric braking force that the motor device can provide to the second axle is less than the target electric braking force, the method is: Determining a second target hydraulic pressure, wherein the third sum of the third hydraulic braking force generated by the second target hydraulic pressure for the front axle and the fourth hydraulic braking force generated by the second target hydraulic pressure for the rear axle is equal to the difference between the total braking force and the maximum electric braking force; Controlling the hydraulic efficiency gear 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 axle; The method according to claim 4, further comprising.

6. Based on the total braking force, controlling a hydraulic efficiency gear in the vehicle to provide a first target hydraulic pressure to a front axle and a rear axle, providing a first electric braking force to the front axle, and controlling a motor device in the vehicle to provide a second electric braking force to the rear axle, the steps are: When a preset condition is satisfied, based on the total braking force, controlling the hydraulic efficiency gear in the vehicle to provide the first target hydraulic pressure to the front axle and the rear axle, providing the first electric braking force to the front axle, and controlling the motor device in the vehicle to provide the second electric braking force to the rear axle, the steps include: The preset condition includes that a change rate of a brake pedal in the vehicle is greater than a preset first threshold, an opening degree of the brake pedal is greater than a preset second threshold, and a slip rate of the vehicle is greater than a preset third threshold. The method according to any one of claims 1 to 5.

7. Based on the total braking force, controlling a hydraulic efficiency gear in the vehicle to provide a first target hydraulic pressure to a front axle and a rear axle, providing a first electric braking force to the front axle, and controlling a motor device in the vehicle to provide a second electric braking force to the rear axle, the steps are: Obtaining mode setting information in the vehicle, the mode setting information includes first mode information and / or second mode information, the first mode information indicates that when the total braking force remains unchanged, a ratio of a braking force of the front axle to a braking force of the rear axle is equal to a ratio of a first vertical load to a second vertical load, and the second mode information indicates that when the total braking force remains unchanged, the motor device can provide a maximum electric braking force to the rear axle, the steps and: When the mode setting information is the first mode information and the vehicle does not satisfy a preset condition, based on the total braking force, control the hydraulic efficiency gear in the vehicle to provide the first target hydraulic pressure to the front axle and the rear axle, provide the first electric braking force to the front axle, and control the motor device in the vehicle to provide the second electric braking force to the rear axle. The preset condition includes any one or more of the following conditions, that is, the change rate of the brake pedal in the vehicle is greater than a preset first threshold, the opening degree 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. Step The method according to any one of claims 1 to 5, including

8. When the mode setting information is the second mode information, the method includes Determining the maximum electric braking force that can be provided by the motor device to the rear axle; Determining a third target hydraulic pressure, wherein a fourth sum of a fifth hydraulic braking force generated by the third target hydraulic pressure for the front axle and a sixth hydraulic braking force generated by the third target hydraulic pressure for the rear axle is equal to a difference between the total braking force and the maximum electric braking force that can be provided to the rear axle. Step Controlling the hydraulic efficiency gear in the vehicle to provide the third target hydraulic pressure to the front axle and the rear axle, and providing the maximum electric braking force to the rear axle through the motor device The method according to claim 7, further including

9. A vehicle braking device, comprising An acquisition module configured to acquire a total braking force, where the total braking force is the braking force required to brake the vehicle. Acquisition module; A control module configured to control the hydraulic efficiency gear in the vehicle to provide a first target hydraulic pressure to the front axle and the rear axle based on the total braking force, provide a first electric braking force to the front axle, and control the motor device in the vehicle to provide a second electric braking force to the rear axle Including An apparatus, wherein the sum of a first hydraulic braking force generated by the first target hydraulic pressure with respect to the front axle, a second hydraulic braking force generated by the first target hydraulic pressure with respect to 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 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 the ratio of a first vertical load of the front axle of the vehicle to a second vertical load of the rear axle of the vehicle.

10. The first target hydraulic pressure is the minimum hydraulic pressure of a first hydraulic pressure and a second hydraulic pressure. The first hydraulic pressure is the hydraulic pressure that needs to be provided by the hydraulic efficiency gear to enable the front axle to generate a first braking force. The second hydraulic pressure is the hydraulic pressure that needs to be provided by the hydraulic efficiency gear to enable the rear axle to generate a second braking force. The first braking force and the second braking force are the braking forces that need to be respectively distributed to the front axle and the rear axle when the total braking force is distributed to the front axle and the rear axle based on the first vertical load and the second vertical load. The electric braking force provided by the motor device to a 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. The apparatus according to claim 9.

11. The control module determines the first braking force that needs to be distributed to the front axle and the second braking force that needs to be distributed to the rear axle when the total braking force is distributed to the front axle and the rear axle based on the first vertical load and the second vertical load; determines the first hydraulic pressure that needs to be provided by the hydraulic efficiency gear to enable the front axle to generate the first braking force; determines the second hydraulic pressure that needs to be provided by the hydraulic efficiency gear to enable the rear axle to generate the second braking force; determines the minimum hydraulic pressure of the first hydraulic pressure and the second hydraulic pressure as the first target hydraulic pressure; determines the hydraulic braking force generated by the second axle when the hydraulic efficiency gear provides the first target hydraulic pressure to a second axle of the front axle and the rear axle. The apparatus according to claim 10, further configured to determine, as a target electric braking force that the motor device needs to provide to the second axle, a difference between a braking force that needs to be distributed to the second axle among the total braking force and the hydraulic braking force generated by the second axle.

12. The control module is further configured to control the hydraulic efficiency gear in the vehicle to provide the first target hydraulic pressure to the front axle and the rear axle, and to control the motor device in the vehicle to provide the target electric braking force to the second axle when the maximum electric braking force that the motor device can provide to the second axle is equal to or greater than the target electric braking force. The apparatus according to claim 11.

13. When 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 further configured to determine a second target hydraulic pressure, wherein a third sum of a third hydraulic braking force generated by the second target hydraulic pressure for the front axle and a fourth hydraulic braking force generated by the second target hydraulic pressure for the rear axle is equal to a difference between the total braking force and the maximum electric braking force. The apparatus according to claim 12, further configured to control the hydraulic efficiency gear in the vehicle to provide the second target hydraulic pressure to the front axle and the rear axle, and to control the motor device in the vehicle to provide the maximum electric braking force to the second axle.

14. The control module is further configured to control the hydraulic efficiency gear in the vehicle to provide the first target hydraulic pressure to the front axle and the rear axle based on the total braking force when a preset condition is satisfied, to provide the first electric braking force to the front axle, and to control the motor device in the vehicle to provide the second electric braking force to the rear axle. The preset condition includes that a change rate of a brake pedal in the vehicle is greater than a preset first threshold, an opening degree of the brake pedal is greater than a preset second threshold, and a slip rate of the vehicle is greater than a preset third threshold. The apparatus according to any one of claims 9 to 13.

15. The control module is Further configured to obtain mode setting information in the vehicle, the mode setting information includes first mode information and / or second mode information, the first mode information indicates 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 indicates that when the total braking force remains unchanged, the motor device can provide the 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, based on the total braking force, the hydraulic efficiency gear in the vehicle is controlled to provide the first target hydraulic pressure to the front axle and the rear axle, the motor device in the vehicle is further configured to provide the first electric braking force to the front axle and the second electric braking force to the rear axle, and the preset conditions include any one or more of the following conditions: that is, the change rate of the brake pedal in the vehicle is greater than a preset first threshold, the opening degree 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. The device according to any one of claims 9 to 13.

16. When the mode setting information is the second mode information, the control module Determines the maximum electric braking force that can be provided by the motor device to the rear axle. Further configured to determine a third target hydraulic pressure, and a fourth sum of a fifth hydraulic braking force generated by the third target hydraulic pressure for the front axle and a sixth hydraulic braking force generated by the third target hydraulic pressure for the rear axle is equal to a difference between the total braking force and the maximum electric braking force that can be provided to the rear axle. The hydraulic efficiency gear in the vehicle is controlled to provide the third target hydraulic pressure to the front axle and the rear axle, and further configured to provide the maximum electric braking force to the rear axle through the motor device. The device according to claim 15.

17. A vehicle braking device including a memory and a processor, The memory is configured to store program instructions. The vehicle braking device, wherein the processor is configured to call the program instructions in the memory and execute the method according to any one of claims 1 to 8. **Claim 18** A vehicle including the device according to any one of claims 9 to 16. **Claim 19** A computer-readable medium, wherein the computer-readable medium stores program code executable by a computer, and the program code includes instructions for executing the method according to any one of claims 1 to 8. **Claim 20** A computer program product, wherein the computer program product includes computer program code, and when the computer program code is executed on a computer, the computer can implement the method according to any one of claims 1 to 8.

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