Brake control method and device, storage medium, program product and vehicle

Abstract

The invention relates to a braking control method and device, a storage medium, a program product and a vehicle, and at least two braking ends are subjected to braking control according to a running road surface. According to the braking control method and the braking control device, the braking control is performed on the at least two braking ends through the driving road surface, so that the multiple braking ends can respectively adopt the same or different braking strategies corresponding to the driving road surface according to different driving road surfaces, the accurate braking of the vehicle is realized, and the braking control effect of the vehicle is improved.

Description

Technical Field

[0001] The present application relates to the field of vehicle control, and in particular to a braking control method, device, storage medium, program product, and vehicle. Background Art

[0002] Vehicle braking, especially when the anti-lock braking system is enabled, affects driving safety.

[0003] Currently, most braking methods control the wheels through motors or hydraulics, and during the control process, they are only controlled and adjusted by the slip rate of the wheels, resulting in inaccurate braking effect of the vehicle. Summary of the Invention

[0004] The embodiments of the present application provide a braking control method, device, storage medium, program product and vehicle, which aim to at least partially solve the above-mentioned problem of unsatisfactory braking effect.

[0005] In a first aspect, the present application provides a braking control method, comprising:

[0006] According to the driving road surface, braking control is performed on at least two braking ends.

[0007] As a feasible implementation scheme of the present application, the driving road surface includes at least one of a uniform road surface, a split road surface and a butt-jointed road surface, and the braking end includes a front axle braking end and a rear axle braking end.

[0008] As a feasible implementation solution of the present application, the at least two braking ends are in contact with the driving road surface.

[0009] As a feasible implementation scheme of the present application, the braking control of at least two braking ends according to the driving road surface includes:

[0010] When the driving road surface is a uniform road surface, braking control is performed on any one or more of the at least two braking ends.

[0011] As a feasible implementation scheme of the present application, when the driving road surface is a uniform road surface, the rear axle is brake-controlled according to the braking yaw parameters of the rear axle braking end, and / or the front axle is brake-controlled according to the braking yaw parameters of the front axle braking end.

[0012] As a feasible implementation solution of the present application, the braking yaw parameter includes at least one of vehicle speed, slope, slip rate, and angular acceleration.

[0013] As a feasible implementation solution of the present application, the braking yaw parameter is obtained through the yaw parameter and the braking segment motion parameter.

[0014] As a feasible implementation solution of the present application, braking control of the rear axle according to the braking yaw parameter of the rear axle braking end includes:

[0015] Braking control of the rear axle according to the slip ratio of the rear axle braking end.

[0016] As a feasible implementation solution of the present application, braking control of the rear axle according to the slip ratio of the rear axle braking end includes:

[0017] Determining the braking torque of the rear axle according to the deviation between the actual slip ratio and the optimal slip ratio of the rear axle braking end to perform braking control on the rear axle.

[0018] As a feasible implementation solution of the present application, braking control of the front axle according to the braking yaw parameter of the front axle braking end includes:

[0019] Braking control of the front axle according to the slip ratio and / or angular acceleration of the front axle braking end.

[0020] As a feasible implementation solution of the present application, braking control of the front axle according to the slip ratio and / or angular acceleration of the front axle braking end includes:

[0021] In the case where the driving road surface is a low-adhesion uniform road surface, braking control of the front axle according to the slip ratio of the front axle braking end; and / or

[0022] In the case where the driving road surface is a high-adhesion uniform road surface, braking control of the front axle according to the angular acceleration of the front axle braking end.

[0023] As a feasible implementation solution of the present application, the road adhesion coefficient of the low-adhesion uniform road surface is lower than that of the high-adhesion uniform road surface.

[0024] As a feasible implementation solution of the present application, braking control of the front axle according to the slip ratio of the front axle braking end includes:

[0025] Braking control of the front axle according to the deviation between the actual slip ratio and the optimal slip ratio of the front axle braking end.

[0026] As a feasible implementation solution of the present application, braking control of the front axle according to the deviation between the actual slip ratio and the optimal slip ratio of the front axle braking end includes:

[0027] Determining the wheel cylinder pressure of the target master cylinder according to the deviation between the actual slip ratio and the optimal slip ratio of the front axle braking end to perform braking control on the front axle through the hydraulic braking force provided by the target master cylinder.

[0028] As a feasible implementation solution of the present application, braking control of the front axle according to the angular acceleration of the front axle braking end includes:

[0029] Determine the wheel cylinder parameters of the wheel cylinder corresponding to the front axle braking end according to the angular acceleration of the front axle braking end, so as to perform braking control on the front axle.

[0030] As a feasible implementation solution of the present application, there are multiple front axle braking ends; the determining the wheel cylinder parameters of the wheel cylinder corresponding to the front axle braking end according to the angular acceleration of the front axle braking end to perform braking control on the front axle includes:

[0031] Determine the wheel cylinder parameters of the branch wheel cylinders corresponding to each front axle braking end respectively according to the actual angular acceleration of each front axle braking end, so as to perform braking control on the front axle.

[0032] As a feasible implementation solution of the present application, the performing braking control on at least two braking ends according to the driving road surface includes:

[0033] When the driving road surface is a oncoming road surface, perform braking control on the rear axle according to the slip ratio of the rear axle braking end, and / or perform braking control on the front axle according to the slip ratio of the front axle braking end.

[0034] As a feasible implementation solution of the present application, there are multiple rear axle braking ends;

[0035] The performing braking control on the rear axle according to the slip ratio of the rear axle braking end includes:

[0036] Determine the braking torque of each rear axle braking end respectively according to the deviation between the actual slip ratio and the optimal slip ratio of each rear axle braking end, so as to perform braking control on the rear axle.

[0037] As a feasible implementation solution of the present application, during the process of performing braking control on the rear axle, the torque difference between the braking torques of multiple rear axle braking ends does not exceed a preset torque threshold.

[0038] As a feasible implementation solution of the present application, the rear axle braking end includes a first rear axle braking end and a second rear axle braking end, and the method further includes:

[0039] If the first braking torque of the first rear axle braking end exceeds the sum of the second braking torque of the second rear axle braking end and the preset torque threshold, then adjust the first braking torque to the sum of the second braking torque of the second rear axle braking end and the preset torque threshold.

[0040] As a feasible implementation solution of the present application, the performing braking control on at least two braking ends according to the driving road surface includes:

[0041] When the driving road surface is a docking road surface, adjust the braking torque of the rear axle braking end until the slip ratio of the rear axle braking end meets the preset working condition, and then perform braking control on the rear axle according to the slip ratio of the rear axle braking end;

[0042] And / or, adjust the hydraulic braking force of the front axle braking end until the slip ratio of the front axle braking end meets the preset working condition, and then perform braking control on the front axle according to the slip ratio and / or angular acceleration of the front axle braking end.

[0043] As a feasible implementation solution of the present application, the docking road surface includes at least one of a first docking road surface and a second docking road surface, wherein the adhesion coefficient of the road surface of the first docking road surface decreases along the driving direction of the vehicle, and the adhesion coefficient of the road surface of the second docking road surface increases along the driving direction of the vehicle.

[0044] As a feasible implementation solution of the present application, adjusting the braking torque of the rear axle braking end includes:

[0045] When the driving road surface of the vehicle is the first docking road surface, reduce the braking torque of the rear axle braking end, and / or

[0046] When the driving road surface of the vehicle is the second docking road surface, increase the braking torque of the rear axle braking end.

[0047] As a feasible implementation solution of the present application, the braking torque of the rear axle braking end is controlled by a rear axle motor.

[0048] As a feasible implementation solution of the present application, until the slip ratio of the rear axle braking end meets the preset working condition, performing braking control on the rear axle according to the slip ratio of the rear axle braking end includes:

[0049] When the driving road surface is the first docking road surface, if the slip ratio of the rear axle braking end is lower than the threshold value, perform braking control on the rear axle according to the slip ratio of the rear axle braking end; and / or

[0050] When the driving road surface is the second docking road surface, if the slip ratio of the rear axle braking end increases, perform braking control on the rear axle according to the slip ratio of the rear axle braking end.

[0051] As a feasible implementation solution of the present application, adjusting the hydraulic braking force of the front axle braking end includes:

[0052] When the driving road surface is the first docking road surface, reduce the hydraulic braking force of the front axle braking end; and / or [[ID=�4]]

[0053] When the driving road surface is the second docking road surface, increase the hydraulic braking force of the front axle braking end.

[0054] As a feasible implementation solution of the present application, the hydraulic braking force at the front axle braking end is provided by a target master cylinder.

[0055] As a feasible implementation solution of the present application, after the slip ratio at the front axle braking end meets the preset working conditions, braking control is performed on the front axle according to the slip ratio and / or angular acceleration at the front axle braking end, including:

[0056] When the driving road surface is the first docking road surface, if the slip ratio at the front axle braking end is lower than the threshold value, braking control is performed on the front axle according to the slip ratio at the front axle braking end; and / or

[0057] When the driving road surface is the second docking road surface, if the slip ratio at the front axle braking end increases, braking control is performed on the front axle according to the angular acceleration at the front axle braking end.

[0058] As a feasible implementation solution of the present application, the method further includes:

[0059] Determine the driving road surface of the vehicle according to the ground adhesion coefficient of each braking end of the vehicle.

[0060] As a feasible implementation solution of the present application, the determining the driving road surface of the vehicle according to the ground adhesion coefficient of each braking end of the vehicle includes:

[0061] When the ground adhesion coefficient of each braking end of the vehicle is less than the preset first adhesion coefficient threshold, determine that the driving road surface of the vehicle is a low-adhesion uniform road surface; and / or

[0062] When the ground adhesion coefficient of each braking end of the vehicle is greater than the preset second adhesion coefficient threshold, determine that the driving road surface of the vehicle is a high-adhesion uniform road surface.

[0063] As a feasible implementation solution of the present application, the determining the driving road surface of the vehicle according to the ground adhesion coefficient of each braking end of the vehicle includes:

[0064] When the ground adhesion coefficient of the front axle braking end of the vehicle is less than the preset third adhesion coefficient threshold and the ground adhesion coefficient of the rear axle braking end is greater than the preset fourth adhesion coefficient threshold, determine that the driving road surface of the vehicle is the first docking road surface; and / or

[0065] When the ground adhesion coefficient of the rear axle braking end of the vehicle is less than the preset third adhesion coefficient threshold and the ground adhesion coefficient of the front axle braking end is greater than the preset fourth adhesion coefficient threshold, determine that the driving road surface of the vehicle is the second docking road surface.

[0066] As a feasible implementation solution of the present application, determining the driving road surface of the vehicle according to the ground adhesion coefficient of each braking end of the vehicle includes:

[0067] When the ratio between the ground adhesion coefficients of the first front axle braking end and the second front axle braking end in the front axle braking end is greater than a preset ratio threshold, and / or when the ratio between the ground adhesion coefficients of the first rear axle braking end and the second rear axle braking end in the rear axle braking end is greater than a preset ratio threshold, determine that the driving road surface of the vehicle is a split road surface.

[0068] As a feasible implementation solution of the present application, the ground adhesion coefficient of each braking end of the vehicle is determined through the following steps:

[0069] Determine the braking torque, load, slip rate angular acceleration of each braking end;

[0070] Determine the ground adhesion coefficient of each braking end according to the braking torque, load, slip rate and vehicle angular acceleration of each braking end.

[0071] As a feasible implementation solution of the present application, the front axle braking end includes the front wheels of the vehicle, and the rear axle braking end includes the rear wheels of the vehicle.

[0072] As a feasible implementation solution of the present application, the method further includes:

[0073] When the anti-lock braking system of the vehicle is activated, execute the step of braking control for at least two braking ends according to the driving road surface.

[0074] As a feasible implementation solution of the present application, the method further includes:

[0075] Determine whether to activate the anti-lock braking system of the vehicle according to the slip rate and / or angular acceleration of the braking end during the vehicle braking process. As a feasible implementation solution of the present application, the method further includes:

[0076] When the anti-lock braking system of the vehicle is not activated, distribute the braking torque corresponding to the braking instruction to each braking end of the vehicle to control each braking end according to the distributed braking torque corresponding to each braking end.

[0077] As a feasible implementation solution of the present application, the method further includes:

[0078] When the distributed braking torque of the target braking end exceeds the maximum allowable feedback torque, control the target braking end according to the maximum allowable feedback torque; and

[0079] Adjust the allocated braking torque of the remaining braking ends based on the difference between the allocated braking torque of the target braking end and the maximum allowable feedback torque, so as to control the remaining braking ends according to the adjusted allocated braking torque.

[0080] In a second aspect, the present application provides a computer-readable storage medium, on which a computer program is stored. It is characterized in that the computer-readable storage medium stores instructions, and when the instructions are executed by a computer, the computer executes the steps of the braking control method described in any one of the above.

[0081] In a third aspect, the present application provides a computer program product. The computer program product stores instructions, and when the instructions are executed by a computer, the computer implements the steps of the braking control method described in any one of the above.

[0082] In a fourth aspect, the present application provides an electronic device, including:

[0083] A memory on which a computer program is stored;

[0084] A processor for executing the computer program in the memory to implement the braking control method described in any one of the above

[0085] In a fifth aspect, the present application provides a vehicle, including the electronic device described above.

[0086] By performing braking control on at least two braking ends through the driving road surface, the present application can enable multiple braking ends to adopt the same or different braking strategies corresponding to the driving road surface respectively according to the differences in the driving road surface, so that each braking end can be in a better working condition that meets the current driving road surface, thereby realizing precise braking of the vehicle and improving the braking control effect of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0088] In order to more completely understand the present application and its beneficial effects, the following will be described in conjunction with the drawings, where the same reference numerals represent the same parts in the following description.

[0089] Figure 1 It is a schematic flowchart of the steps of a braking control method provided by an embodiment of the present application;

[0090] Figure 2Schematic diagram of the step flow of braking control in the case of a uniform road surface provided by an embodiment of the present application;

[0091] Figure 3 Schematic diagram of the step flow of controlling the front axle braking end under a uniform road surface with different adhesion coefficients provided by an embodiment of the present application;

[0092] Figure 4 Schematic diagram of the step flow of the braking control method for the braking end under a split road surface provided by an embodiment of the present application;

[0093] Figure 5 Schematic diagram of the step flow of the braking control method for the rear axle braking end under different docking road surfaces provided by an embodiment of the present application;

[0094] Figure 6 Schematic diagram of the step flow of the braking control method for the front axle braking end under different docking road surfaces provided by an embodiment of the present application;

[0095] Figure 7 Schematic diagram of another step flow of determining the ground adhesion coefficient based on the driving data of the vehicle to determine the road surface type provided by an embodiment of the present application;

[0096] Figure 8a Flowchart of a braking control method provided by an embodiment of the present application;

[0097] Figure 8b Schematic diagram of the flow of the braking control strategy under a uniform low - adhesion road surface provided by an embodiment of the present application;

[0098] Figure 8c Schematic diagram of the flow of the braking control strategy under a uniform high - adhesion road surface provided by an embodiment of the present application;

[0099] Figure 8d Schematic diagram of the flow of the braking control strategy under a split road surface provided by an embodiment of the present application;

[0100] Figure 8e Schematic diagram of the process of high - adhesion to low - adhesion docking road surface provided by an embodiment of the present application;

[0101] Figure 8f Schematic diagram of the process of low - adhesion to high - adhesion docking road surface provided by an embodiment of the present application;

[0102] Figure 9 Schematic diagram of the structure of a distributed vehicle electro - hydraulic composite anti - lock braking control system for implementing the braking control method provided by an embodiment of the present application;

[0103] Figure 10 Schematic diagram of the structure of an electronic device provided by an embodiment of the present application. Detailed implementation manners

[0104] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative efforts belong to the protection scope of the present application.

[0105] To clearly understand the implementation solution of the braking control method provided in the embodiments of the present application, the application scenarios of vehicle braking will be specifically described below. Specifically, the braking control method provided in the present application is mainly applied to the braking scenario of a vehicle, especially applicable to the scenario where the anti-lock brake system (ABS) function of the vehicle is enabled. Currently, the common braking methods on electric vehicles include a regenerative braking method that generates negative torque through a drive motor and charges the power battery. However, limited by the battery, motor, and vehicle speed of the electric vehicle, since the regenerative braking cannot provide stable braking force, after the ABS function is activated, it is usually necessary to exit the regenerative braking of the motor and thus use a more stable hydraulic braking control, resulting in the inability to fully utilize the motor feedback energy.

[0106] Currently, although the related technology has proposed an electro-hydraulic composite ABS control technology, that is, after the ABS function is enabled, the vehicle is controlled by combining the regenerative braking provided by the motor and the hydraulic braking. However, most of them keep the regenerative braking at a certain value and further adjust the hydraulic braking, resulting in an unsatisfactory actual braking effect.

[0107] It is precisely to solve the above technical problems that the present application provides a braking control method. By controlling at least two braking ends according to the driving road surface during the braking process of the vehicle, in the application scenario of the electro-hydraulic composite ABS control technology, the braking effect of the vehicle can be effectively guaranteed, thereby improving the braking experience of users.

[0108] Specifically, to facilitate the understanding of the braking control method provided in the present application, the following will be described separately. As Figure 1 shown, Figure 1 is a schematic flowchart of the steps of a braking control method provided in an embodiment of the present application, including steps S110 to S120:

[0109] S110, determine the driving road surface.

[0110] In the embodiments of the present application, braking control is usually executed by triggering a braking instruction for the vehicle. Herein, the braking instruction of the vehicle can be understood as an instruction for reducing the vehicle speed triggered by the user in a specific scenario. For example, as a common feasible implementation, the user can trigger the braking instruction by stepping on the brake pedal. Of course, other ways of triggering the braking instruction are also feasible. The present application does not limit the way of triggering the braking instruction, and any instruction for controlling the reduction of the vehicle speed can be regarded as the braking instruction in this embodiment. On this basis, different from directly performing braking control on the wheels after triggering the braking instruction, in this embodiment, the driving road surface will be further determined first to further execute the subsequent steps of controlling the braking end based on the driving road surface.

[0111] In addition, it can be understood that in the above implementation, it is necessary to accurately identify the driving road surface of the vehicle. Otherwise, incorrect control strategies may be used due to incorrect identification of the driving road surface, which will affect the subsequent braking control. Currently, the conventional method for identifying the driving road surface usually identifies the type of the driving road surface through the collected road surface images, such as dry asphalt road surface, compacted snow surface, polished ice surface, and then further determines whether the driving road surface is a uniform road surface, a oncoming road surface, a butt joint road surface, etc. However, the accuracy of image recognition is not high, and an additional image acquisition device needs to be provided, which increases the cost of the vehicle. Therefore, as a further feasible implementation of the present application, a solution will be provided later to determine the road surface adhesion coefficient by collecting vehicle driving data, and then directly determine the driving road surface accurately through the road surface adhesion coefficient and its change, so as to ensure the realization of the vehicle braking effect. The specific details will be described in detail in the subsequent embodiments.

[0112] S120, perform braking control on at least two braking ends according to the driving road surface.

[0113] On the basis of determining the driving road surface above, the braking control method provided in this embodiment will further perform braking control on at least two braking ends according to the difference of the driving road surface. The braking end can be understood as the terminal device for realizing vehicle braking. For example, more commonly, the braking end can usually be understood as the wheels of the vehicle, that is, the braking effect of the vehicle is realized by braking the wheels. For the convenience of description, the braking ends will be described by taking the wheels of the vehicle as an example hereinafter.

[0114] Specifically, due to the difference in the road surface adhesion coefficient of the driving road surface, different control strategies are set for different driving road surfaces during the process of performing braking control on the braking end, so that more effective braking control can be effectively performed on the braking end under different driving road surfaces. Among them, the specific strategies for controlling the braking end under different driving road surfaces will be specifically described in the subsequent embodiments.

[0115] For ease of understanding, the following takes the driving road surface including a uniform road surface, an oncoming road surface, a docking road surface, etc. as an example to explain the braking control of the front axle braking end and the rear axle braking end included in the braking end, and the details are as follows.

[0116] In one embodiment, taking the driving road surface as a uniform road surface, that is, a road surface where the adhesion coefficient of the road surface remains relatively unchanged or changes by no more than a preset threshold, at this time, according to the driving road surface, braking control is performed on at least two braking ends, which generally includes:

[0117] When the driving road surface is a uniform road surface, braking control is performed on any one or more of at least two of the braking ends.

[0118] Specifically, when the driving road surface is a uniform road surface, performing braking control on any one or more of at least two of the braking ends generally means controlling the front axle braking end or the rear axle braking end. In particular, it is controlled by the braking yaw parameters of the front axle braking end or the rear axle braking end. That is to say, the braking control method includes:

[0119] When the driving road surface is a uniform road surface, the rear axle is braked according to the braking yaw parameter of the rear axle braking end, and / or the front axle is braked according to the braking yaw parameter of the front axle braking end.

[0120] Among them, the braking yaw parameter here is usually obtained from the yaw parameter and the braking end movement parameter, and generally includes at least one of vehicle speed, slope, slip ratio, and angular acceleration.

[0121] Specifically, for ease of understanding the above content, please refer to Figure 2 , which provides a schematic flow chart of the steps of a specific control method for the braking end under a uniform road surface. Specifically, it includes steps S210 to S220:

[0122] S210, the rear axle is braked according to the slip ratio of the rear axle braking end.

[0123] Considering that most of the braking process depends on the adhesion force provided by the rear axle to ensure the smoothness of braking, therefore, when the driving road surface of the vehicle is a uniform road surface, it is possible to consider realizing the closed-loop adjustment of the slip ratio with the slip ratio of the rear axle braking end, so as to ensure the braking effect of the rear axle.

[0124] Specifically, as a feasible implementation scheme, braking control of the rear axle according to the slip ratio of the rear axle braking end includes:

[0125] Determine the braking torque of the rear axle according to the deviation between the actual slip ratio and the optimal slip ratio of the rear axle braking end to brake control the rear axle.

[0126] In the embodiments of the present application, the deviation between the actual slip ratio and the optimal slip ratio of the rear axle braking end is used as the control target. That is, the closed-loop regulation of the target slip ratio is realized by calculating the target feedback torque through a PID (Proportional Integral Derivative, a control system based on proportion, integral and differential) controller, which can make the rear wheels make more full use of the ground adhesion, contributing to lateral stability and braking smoothness.

[0127] S220, perform braking control on the front axle according to the slip ratio and / or angular acceleration of the front axle braking end.

[0128] Corresponding to the rear axle braking, considering that during the braking process, the front axle braking is mainly to maintain the balance during braking, and the braking force provided by the front axle braking end is adjusted through the center of gravity distribution of the front and rear axles of the vehicle. And because the degree of forward movement of the vehicle's center of gravity is different on road surfaces with different adhesion coefficients, therefore, during the process of performing braking control on the front axle braking end, it can be considered to perform braking control on the front axle based on the slip ratio and / or angular acceleration of the front axle braking end. In particular, for different adhesion coefficients in a uniform road surface, corresponding braking yaw parameters can be used to achieve braking control. Specifically, please refer to Figure 3 , Figure 3 which is a schematic flow chart of the steps of the braking control method for the front axle braking end on a uniform road surface with different adhesion coefficients provided by the embodiments of the present application. Specifically, it includes steps S310 to S320:

[0129] S310, when the driving road surface is a low-adhesion uniform road surface, perform braking control on the front axle according to the slip ratio of the front axle braking end.

[0130] S320, when the driving road surface is a high-adhesion uniform road surface, perform braking control on the front axle according to the angular acceleration of the front axle braking end.

[0131] In the embodiments of the present application, a low-adhesion uniform road surface refers to a road surface with a relatively low road surface adhesion coefficient, while a high-adhesion uniform road surface refers to a road surface with a relatively high road surface adhesion coefficient, that is, the road surface adhesion coefficient of the low-adhesion uniform road surface is usually lower than that of the high-adhesion uniform road surface. For example, a road surface with a road surface adhesion coefficient lower than a preset threshold can be determined as a low-adhesion uniform road surface, and a road surface with a road surface adhesion coefficient higher than a preset threshold can be determined as a high-adhesion uniform road surface. Of course, other ways to determine the low-adhesion uniform road surface and the high-adhesion uniform road surface are also feasible, and this embodiment does not make any restrictions.

[0132] Specifically, considering that the forward shift of the vehicle's center of gravity can be ignored on a low-adhesion uniform road surface, therefore, using a low-selection strategy for the front axle will not result in excessive loss of braking force. That is, in this embodiment, when the vehicle is traveling on a low-adhesion uniform road surface, the front axle braking end can obtain the optimal slip ratio based on the road surface adhesion coefficient, and then use the deviation between the actual slip ratio of the front axle braking end and the optimal slip ratio as the control target, and calculate the required braking force through a PID controller to ensure that the slip ratio of the front axle braking end can quickly converge near the optimal slip ratio, thereby improving the braking effect.

[0133] Furthermore, different from the low-adhesion uniform road surface, because the high-adhesion uniform road surface provides a relatively high adhesion force, therefore, for the front axle braking end, in order to enable the front axle braking end to make full and effective use of the ground adhesion force to ensure the braking effect, it can be based on the angular acceleration of the front axle braking end and use a control strategy with a logical threshold value to control the front axle braking. In particular, the wheel cylinder parameters of the wheel cylinder corresponding to the front axle braking end can be determined according to the angular acceleration of the front axle braking end to control the front axle braking.

[0134] Specifically, on the basis that there are multiple front axle braking ends, such as the first front axle braking end and the second front axle braking end, that is, the left front axle wheel and the right front axle wheel, the wheel cylinder parameters of the wheel cylinder corresponding to the front axle braking end are determined according to the angular acceleration of the front axle braking end to control the front axle braking, which specifically includes:

[0135] According to the actual angular acceleration of each front axle braking end, the wheel cylinder parameters of the branch wheel cylinder corresponding to each front axle braking end are respectively determined to control the front axle braking.

[0136] In this embodiment, different from controlling the front axle braking end synchronously through the target master wheel cylinder under a low-adhesion uniform road surface, under a high-adhesion uniform road surface, multiple front axle braking ends will be independently controlled. That is, generally, a control method based on a logical threshold value can be used, that is, control each front axle braking end to enter a control logic with the wheel angular acceleration as the main threshold, so as to correspondingly determine the control parameters of different branch wheel cylinders for controlling different front axle braking ends, such as including control states (such as pressure increase, pressure reduction, pressure maintenance), as well as the corresponding pressure increase rate, pressure maintenance time, and target pressure relief amount, so as to independently control each front axle braking end near the optimal slip ratio. Thus, each front axle braking end can make full and effective use of the ground adhesion force to ensure the braking effect. And in this process, the pressure of the target master wheel cylinder is usually calculated by subtracting the actual torque provided by the rear axle braking end from the total braking torque requirement.

[0137] By means of the control strategy provided above, that is, low-selection control and independent control are respectively performed on the front-axle braking end on a uniform road surface with different road surface adhesion coefficients, the requirements for different road surface conditions can be met, and the braking control effect of the vehicle can be further improved.

[0138] Furthermore, in another embodiment, taking a split road surface as an example for illustration, where a split road surface refers to a road surface where the road surface adhesion coefficients on both sides of the driving road surface are different, especially a road surface where there is a large difference in the road surface adhesion coefficients on both sides. For example, one side is an asphalt road surface, and the other side is a muddy road surface or an icy road surface, etc. At this time, braking control is performed on any one or more of at least two of the braking ends, which generally includes:

[0139] Performing braking control on the rear axle according to the slip ratio of the rear-axle braking end, and / or performing braking control on the front axle according to the slip ratio of the front-axle braking end.

[0140] Specifically, on a split road surface, for the braking end, especially the rear-axle braking end, it is often necessary to increase the braking force on the high-adhesion side as much as possible. However, due to the large difference in braking forces on both sides, it may often cause the vehicle body to roll over. Therefore, the difference in braking torques provided on both sides needs to be limited by the vehicle speed and the yaw rate, so as to ensure that the yaw rate of the vehicle body is within an acceptable range as much as possible. That is to say, there are multiple rear-axle braking ends. At this time, performing braking control on the rear axle according to the slip ratio of the rear-axle braking end includes:

[0141] Determining the braking torque of each rear-axle braking end respectively according to the deviation between the actual slip ratio and the optimal slip ratio of each rear-axle braking end, so as to perform braking control on the rear axle.

[0142] Among them, if in the process of braking control, in order to avoid too large a difference in braking torques provided on both sides, it is necessary to control the torque difference between the braking torques of multiple rear-axle braking ends not to exceed a preset torque threshold. For example, when the torque difference between the braking torques provided by multiple rear-axle braking ends exceeds the preset threshold, it is necessary to consider adjusting the larger braking torque on the high-adhesion side to the sum of the smaller braking torque on the low-adhesion side and the preset threshold. Here, the preset threshold can usually be set based on the vehicle speed and the acceptable yaw rate range, so as to avoid the vehicle body rolling over due to too large a difference in braking torques on both sides.

[0143] Specifically, for easy understanding of the above content, please refer to Figure 4 , Figure 4 which is a schematic flow chart of the braking control method for the braking end under a split road surface provided by the embodiment of the present application. Specifically, it includes steps S410 to S420:

[0144] S410. Determine the braking torque of each rear axle braking end respectively according to the deviation between the actual slip ratio and the optimal slip ratio of each rear axle braking end.

[0145] In the embodiment of the present application, in the process of generating a feedback braking torque based on the deviation between the actual slip ratio and the optimal slip ratio of each rear axle braking end to control each rear axle braking end, it is usually required that the torque difference between multiple rear axle braking ends does not exceed a preset threshold. For example, it is required that the torque difference between the feedback braking torque of the left rear wheel of the rear axle and the feedback braking torque of the right rear wheel of the rear axle does not exceed a preset torque threshold, so as to avoid too large a difference in the braking torque provided on both sides, thereby avoiding vehicle rollover while ensuring the braking effect of the vehicle as much as possible.

[0146] S420. If the first braking torque of the first rear axle braking end exceeds the sum of the second braking torque of the second rear axle braking end and the preset torque threshold, adjust the first braking torque to the sum of the second braking torque and the preset torque threshold.

[0147] In this embodiment, if during the control process, it is detected that the first braking torque of the first rear axle braking end exceeds the sum of the second braking torque of the second rear axle braking end and the preset torque threshold. For example, the feedback braking torque of the left rear wheel of the rear axle exceeds the sum of the feedback braking torque of the right rear wheel of the rear axle and the preset torque threshold. At this time, usually, the larger braking torque is controlled and adjusted, that is, the larger first braking torque is reduced and adjusted to the sum of the smaller second braking torque and the preset braking torque, so as to avoid the difference in the braking torque on both sides exceeding the threshold. Among them, the preset threshold here usually refers to a torque threshold determined by the vehicle speed and / or the acceptable yaw angular velocity range.

[0148] Of course, the foregoing is described by taking the control strategy for the braking end of the rear axle under the starting working condition as an example. In fact, for the braking end of the front axle, it can independently control the braking ends of both sides of the front axle through a control strategy similar to that of the rear axle braking end. On the basis of providing high adhesion as much as possible, vehicle rollover can be avoided. Of course, considering that the braking end of the front axle is controlled by a hydraulic braking system, therefore, the braking end of the front axle can simplify the use of the low-selection strategy, that is, to connect the master wheel cylinder and the branch wheel cylinder in the hydraulic braking system, and adjust the wheel cylinder pressure of the master cylinder to realize the adjustment of the hydraulic pressure of the two branch wheel cylinders. Taking the deviation between the average actual slip ratio of the two front axle braking ends and the optimal slip ratio as the control target, the wheel cylinder pressure of the master wheel cylinder is calculated in real time by a PID controller to complete the braking control of the front axle braking end. Of course, in the above process, the wheel cylinder pressure of the master wheel cylinder is limited by the difference between the required braking torque and the actual braking torque provided by the rear axle dual motors, that is, the braking torque provided by the wheel cylinder pressure of the master wheel cylinder generally does not exceed the difference between the required braking torque and the actual braking torque provided by the rear axle dual motors, so as to avoid providing excessive braking torque and thus affecting vehicle braking safety.

[0149] Through the control strategy provided above for the split road surface working condition, on the basis of ensuring high lateral braking force as much as possible, that is, making full use of the road adhesion of the high-adhesion side road surface, stable braking of the vehicle can be realized on the premise of avoiding vehicle rollover, thereby improving the braking effect.

[0150] In yet another embodiment, taking the driving road surface as a butt joint road surface as an example, where the butt joint road surface can refer to a road surface composed of two road surfaces with different road adhesion coefficients spliced along the vehicle driving direction. That is to say, the butt joint road surface can be understood as a road surface where the road adhesion coefficient changes along the driving direction of the vehicle. Here, the change can be a stable change in the road adhesion coefficient. For example, as the thickness of the ice layer on the road surface increases, the road adhesion coefficient gradually decreases, or as the asphalt road surface gradually dries, the road adhesion coefficient gradually increases. It can also refer to a sudden change in the road adhesion coefficient. For example, driving from an asphalt road surface with a relatively high adhesion coefficient to an ice road surface with a relatively low adhesion coefficient, or driving from a wet asphalt road surface with a relatively low adhesion coefficient to a muddy road surface with a relatively high adhesion coefficient, etc. The embodiments of the present application do not limit the butt joint road surface here.

[0151] Under this driving road surface, in order to enable the braking ends of the front axle and the rear axle to better adapt to the change of the road adhesion coefficient, as a feasible implementation solution of the present application, it is necessary to first adjust the braking force of the braking end of the front axle and / or the rear axle. After meeting certain working conditions, then continue to perform braking control according to the braking deviation parameters of the braking end of the front axle and / or the rear axle. That is to say, the braking control of at least two braking ends according to the driving road surface includes:

[0152] When the driving road surface is a docking road surface, adjust the braking torque of the rear axle braking end until the slip ratio of the rear axle braking end meets the preset working conditions, and then perform braking control on the rear axle according to the slip ratio of the rear axle braking end;

[0153] And / or, adjust the hydraulic braking force of the front axle braking end until the slip ratio of the front axle braking end meets the preset working conditions, and then perform braking control on the front axle according to the slip ratio and / or angular acceleration of the front axle braking end.

[0154] It should be noted that considering that the docking road surface usually includes a first docking road surface with a reduced road surface adhesion coefficient, that is, converted from a high road surface adhesion coefficient to a low road surface adhesion coefficient, and a second docking road surface with an increased road surface adhesion coefficient, that is, converted from a low road surface adhesion coefficient to a high road surface adhesion coefficient. And under different docking road surface conditions, the control processes for different braking ends are usually different. The following will describe the control processes for different braking ends separately.

[0155] Specifically, please refer to Figure 5 , which provides a schematic diagram of the step flow for the rear axle braking end under different docking road surfaces. Specifically, it includes steps S510 to S520:

[0156] S510, when the driving road surface is the first docking road surface, reduce the braking torque of the rear axle braking end. If the slip ratio of the rear axle braking end is lower than the threshold value, perform braking control on the rear axle according to the slip ratio of the rear axle braking end.

[0157] In this embodiment, the braking torque of the rear axle braking end is usually controlled by the rear axle motor. At this time, when the driving road surface of the vehicle is the first docking road surface converted from a high road surface adhesion coefficient to a low road surface adhesion coefficient, the braking torque of the rear axle braking end can be quickly controlled to decrease by the rear axle motor, that is, the motor torque output by the rear axle motor. And when the motor torque decreases to a certain threshold value, observe whether the slip ratio of the rear axle braking end is lower than the threshold value, and enter the rear axle low-adhesion independent control logic when the slip ratio is lower than the threshold value, so as to perform braking control on the rear axle according to the slip ratio of the rear axle braking end, that is, execute the scheme of controlling each rear axle braking end according to the deviation between the actual slip ratio and the optimal slip ratio of the rear axle braking end mentioned above. That is, with the deviation between the respective actual slip ratio and the optimal slip ratio as the control target, the closed-loop regulation of the target slip ratio is realized by calculating the target feedback torque through the PID controller, so that the slip ratio of each rear axle braking end can converge to the optimal slip ratio.

[0158] S520, when the driving road surface is the second docking road surface, increase the braking torque of the rear axle braking end. If the slip ratio of the rear axle braking end increases, perform braking control on the rear axle according to the slip ratio of the rear axle braking end.

[0159] In the embodiment of the present application, corresponding to the working condition of the foregoing first docking road surface, when the driving road surface is a second docking road surface with a low road surface adhesion coefficient converted to a high road surface adhesion coefficient, by controlling the rear axle motor to enter a rapid torque increase state to rapidly increase the motor torque output by the rear axle motor, it is possible to rapidly increase the braking torque at the braking end of the rear axle. When the output motor torque rises to a certain threshold, it is observed whether the slip ratio at the braking end of the rear axle begins to increase. If the slip ratio at the braking end of the rear axle begins to increase, the high-adhesion independent control logic of the braking end of the rear axle is entered, that is, the process of determining the braking torque of each braking end of the rear axle according to the deviation between the actual slip ratio and the optimal slip ratio of each braking end of the rear axle to control each braking end of the rear axle is executed. Among them, the high-adhesion independent control logic of the rear axle is similar to the foregoing low-adhesion independent control logic of the rear axle, that is, it is necessary to use the deviation between the respective actual slip ratio and the optimal slip ratio as the control target, that is, to realize the closed-loop regulation of the target slip ratio by calculating the target feedback torque through a PID controller. However, in the control process, it is necessary to control that the braking torque actually output by the rear axle motor and the braking torque generated by the actual pressure of the front axle hydraulic system do not exceed the required braking torque.

[0160] Of course, in addition to the control strategy for the braking end of the rear axle provided above, in the docking road surface, it is also necessary to control and adjust the braking force of the braking end of the front axle, such as hydraulic braking force, so as to control the front axle. Similarly, the control of the braking end of the front axle also needs to depend on different docking road surface working conditions. Specifically, please refer to Figure 6 , Figure 6 which is a schematic flow chart of the steps of the braking control method for the braking end of the front axle under different docking road surfaces provided by the embodiment of the present application. Specifically, it includes steps S610 to S620:

[0161] S610, when the driving road surface is the first docking road surface, reduce the hydraulic braking force of the braking end of the front axle. If the slip ratio of the braking end of the front axle is lower than the threshold, brake control is performed on the front axle according to the slip ratio of the braking end of the front axle.

[0162] In this embodiment, when the driving road surface of the vehicle is the first docking road surface where the high road surface adhesion coefficient is converted into the low road surface adhesion coefficient, during the process of the front axle braking end entering from high adhesion to low adhesion, the braking system of the front axle braking end, such as a hydraulic braking system, needs to enter a continuous pressure relief stage for a period of time, that is, it is necessary to reduce the hydraulic braking force of the front axle braking end. Further, the master cylinder can be connected to the two branch cylinders to minimize the time required for the slip rate to decrease when the front wheels enter the low adhesion, and when the slip rate returns to the threshold value, enter the low adhesion and low selection control logic, that is, control the process of the front axle braking end according to the deviation between the actual slip rate and the optimal slip rate of the front axle braking end. Specifically, it is to use the deviation between the average value of the actual slip rate of the front axle braking end and the optimal slip rate as the control target, and calculate the required target master cylinder pressure through a PID controller to adjust the hydraulic braking force of the front axle.

[0163] S620. When the driving road surface is the second docking road surface, increase the hydraulic braking force of the front axle braking end. If the slip rate of the front axle braking end increases, brake control is performed on the front axle according to the angular acceleration of the front axle braking end.

[0164] In this embodiment, similarly, when the driving road surface of the vehicle is the second docking road surface where the low road surface adhesion coefficient is converted into the high road surface adhesion coefficient, there is also a process of the front axle braking end entering from low adhesion to high adhesion. At this time, the hydraulic braking system of the front axle braking end can be controlled to enter a continuous pressure increase stage for a period of time. Further, similarly, the master cylinder can be connected to the two branch cylinders to minimize the deceleration recovery time of the vehicle from low adhesion to high adhesion. At the same time, when the master cylinder pressure reaches a certain threshold value, or when the slip rate of the front axle braking end begins to increase, enter the high adhesion independent control logic. That is, perform brake control on the front axle according to the angular acceleration of the front axle braking end. In particular, when there are multiple front axle braking ends, the control parameters of the branch cylinders corresponding to each front axle braking end can be determined according to the angular acceleration of each front axle braking end. Specifically, it is to control the front axle braking end to enter the threshold value control logic with the angular acceleration as the main threshold, so as to correspondingly determine the control parameters of the different branch cylinders for controlling different front axle braking ends, such as including the control state (such as pressure increase, pressure reduction, pressure holding), as well as the corresponding pressure increase rate, pressure holding time, and target pressure relief amount, so as to independently control each front axle braking end near the optimal slip rate.

[0165] Through the control strategy provided above, it is possible to effectively control the braking ends of the front and rear axles through the electric motor braking system under different docking road surface conditions, so as to quickly respond to the change of the road surface adhesion coefficient, quickly increase / decrease the regenerative braking torque provided by the rear axle motor, thereby avoiding the rear axle from skidding when passing through the docking point of the road surface (i.e., the position where the road surface adhesion coefficient changes suddenly), and at the same time, the vehicle deceleration can be quickly restored, improving the control effect of the vehicle.

[0166] Among them, in the solutions provided in any of the foregoing embodiments, the braking system for controlling the rear axle braking end is an electric motor braking system, that is, a control system that brakes the wheels depending on the braking torque output by the motor. For example, the motor regenerative braking system in an electric vehicle, and the braking system for controlling the front axle braking end is taken as a hydraulic braking system, that is, a control system that brakes the wheels with the pressure provided by the hydraulic pressure for illustration.

[0167] In addition, it can be understood that in the above implementation solutions, it is necessary to accurately identify the driving road surface of the vehicle. Otherwise, incorrect control strategies may be used due to incorrect identification of the driving road surface, which will affect the subsequent braking control. Currently, the conventional driving road surface identification usually identifies the type of the driving road surface through the collected road surface images, such as dry asphalt road surface, compacted snow surface, polished ice surface, and then further determines whether the driving road surface is a uniform road surface, a two-way road surface, a docking road surface, etc. However, the accuracy of image recognition is not high, and an additional image acquisition device needs to be provided, increasing the cost of the vehicle. Therefore, as a further feasible implementation solution of the present application, a solution will be provided later to determine the road surface adhesion coefficient by collecting the vehicle driving data, so as to directly determine the driving road surface accurately through the road surface adhesion coefficient and its change, thereby ensuring the realization of the vehicle braking effect. Specifically, it will be described in detail in the subsequent embodiments.

[0168] Please refer to Figure 7 , and another schematic diagram of the step flow for determining the ground adhesion coefficient based on the vehicle driving data to determine the road surface type is also provided. Specifically, it includes steps S710 to S730:

[0169] S710, determine the braking torque, load, slip ratio, and angular acceleration of each braking end.

[0170] In this embodiment, due to the differences in the braking systems for controlling each braking end, the calculation methods for the braking torque of each braking end are usually different. For example, for a hydraulic braking system, the braking torque is usually related to the brake disc friction coefficient, the piston radius of the brake wheel cylinder, the effective radius of the caliper, etc., while for an electric motor braking system, the braking torque is usually related to the braking torque provided by the motor. For the load of each braking end, it can usually be calculated based on the longitudinal acceleration of the whole vehicle and the estimated mass of the whole vehicle. In addition, for the slip ratio and angular acceleration, the corresponding data signals can be collected through the corresponding sensors.

[0171] S720. Determine the ground adhesion coefficient of each braking end according to the braking torque, load, slip ratio, and angular acceleration of each braking end.

[0172] On the basis of the above, by integrating the angular velocity of the braking end using the moment of inertia of the braking end, the longitudinal force of each braking end can be calculated, and thus the ground adhesion coefficient related to the slip ratio can be determined according to the actual load of each braking end. Among them, the ground adhesion coefficients under different road surface types, such as the longitudinal adhesion coefficient and the lateral adhesion coefficient, and the slip ratio can be determined in advance through experiments for further subsequent calculations.

[0173] S730. Determine the driving road surface of the vehicle according to the ground adhesion coefficient of each braking end.

[0174] In the embodiment of the present application, after determining the ground adhesion coefficients of each braking end, such as the left rear wheel and the right rear wheel of the rear axle braking end and the left front wheel and the right front wheel of the front axle braking end, by judging the ground adhesion coefficients of the braking ends, the driving road surface of the vehicle can be accurately determined.

[0175] Specifically, determining the driving road surface of the vehicle according to the ground adhesion coefficient of each braking end usually includes the following solutions:

[0176] When the ground adhesion coefficient of each braking end is less than a preset first adhesion coefficient threshold, determine that the driving road surface of the vehicle is a low-adhesion uniform road surface;

[0177] When the ground adhesion coefficient of each braking end is greater than a preset second adhesion coefficient threshold, determine that the driving road surface of the vehicle is a high-adhesion uniform road surface;

[0178] When the ground adhesion coefficient of the front axle braking end is less than a preset third adhesion coefficient threshold and the ground adhesion coefficient of the rear axle braking end is greater than a preset fourth adhesion coefficient threshold, determine that the driving road surface of the vehicle is a first docking road surface;

[0179] When the ground adhesion coefficient at the braking end of the rear axle is less than a preset third adhesion coefficient threshold, and the ground adhesion coefficient at the braking end of the front axle is greater than a preset fourth adhesion coefficient threshold, determining that the driving road surface of the vehicle is a second abutting road surface;

[0180] When the ratio between the ground adhesion coefficients of the first front axle braking end and the second front axle braking end in the front axle braking end is greater than a preset ratio threshold, and / or when the ratio between the ground adhesion coefficients of the first rear axle braking end and the second rear axle braking end in the rear axle braking end is greater than a preset ratio threshold, it is determined that the road surface of the vehicle is a split road.

[0181] Specifically, for ease of understanding, the following description will be made with reference to specific embodiments. For example, when the adhesion coefficients of all four wheels are less than or equal to 0.3, the vehicle is in a low-adhesion, uniform road condition; when the adhesion coefficients of all four wheels are greater than 0.7, the vehicle is in a high-adhesion, uniform road condition; when the adhesion coefficients of all four wheels are between 0.3 and 0.7, the vehicle is in a medium-adhesion, uniform road condition; when the ratio of the adhesion coefficients of the front and rear axles exceeds 4, the vehicle is in a split condition; when the adhesion coefficients of the front axle are less than 0.3 and the rear axle are greater than 0.7, the vehicle is in a first, high-adhesion to low-adhesion, docking condition; and when the adhesion coefficients of the front axle are greater than 0.7 and the rear axle are less than 0.3, the vehicle is in a second, low-adhesion to high-adhesion, docking condition.

[0182] Furthermore, it should be noted that the braking control method provided by this application is particularly suitable for use in scenarios where the vehicle's anti-lock braking system is enabled, thereby better braking the wheels and preventing abnormal braking phenomena such as side slipping. Therefore, as another feasible embodiment of this application, the braking control method further includes:

[0183] When the anti-lock braking system of the vehicle is activated, the step of performing braking control on at least two braking ends according to the driving road surface is performed.

[0184] That is, in this embodiment, only when the vehicle's anti-lock braking system (ABS) is detected to be activated will the aforementioned control strategy corresponding to the vehicle's road surface be executed to control the vehicle's braking end, thereby better controlling the braking end and avoiding the risk of losing control of the vehicle's steering due to vehicle skidding. Furthermore, specifically, activation of the vehicle's anti-lock braking system (ABS) can be achieved by determining the slip rate and / or angular acceleration of the braking end, that is, the wheel, during the vehicle's braking process. In other words, the braking control method further includes:

[0185] Whether to activate the anti-lock braking system of the vehicle is determined according to the slip rate and / or angular acceleration of the braking end during the vehicle braking process.

[0186] Among them, the slip ratio and angular velocity of the braking end can usually be calculated by a vehicle control unit (VCU) from various signals collected by various sensors, such as wheel speed sensors and yaw rate sensors, such as longitudinal and lateral acceleration signals, yaw rate signals, wheel speed signals, and steering wheel angle information. Of course, it is also feasible to obtain the slip ratio and angular velocity of the braking end by other means. This embodiment does not limit the implementation scheme for determining the slip ratio and / or angular acceleration of the braking end.

[0187] Furthermore, there are usually various implementation schemes for determining whether to activate the anti-lock braking system of the vehicle according to the slip ratio and / or angular acceleration of the braking end during the vehicle braking process:

[0188] For example, in a feasible implementation scheme, it is possible to determine whether to activate the anti-lock braking system of the vehicle solely based on the slip ratio of the braking end. For example, when the slip ratio of the braking end is greater than a preset first slip ratio threshold, it can be confirmed that the anti-lock braking system of the vehicle is activated, and then the subsequent control strategy corresponding to the driving road surface of the vehicle can be further executed to control the braking end of the vehicle.

[0189] Or, in another feasible implementation scheme, it is also possible to determine whether to activate the anti-lock braking system of the vehicle solely based on the angular acceleration of the braking end. For example, when the angular acceleration of the braking end is greater than a preset first angular acceleration threshold, it can be determined that the anti-lock braking system of the vehicle is activated, and then the subsequent control strategy corresponding to the driving road surface of the vehicle can be further executed to control the braking end of the vehicle.

[0190] Or, in yet another feasible implementation scheme, it is also possible to determine whether to activate the anti-lock braking system of the vehicle based on both the slip ratio and angular acceleration of the braking end. For example, when the slip ratio of the braking end is greater than a preset second slip ratio threshold and the angular acceleration of the braking end is greater than a preset second angular acceleration threshold, it can be determined that the anti-lock braking system of the vehicle is activated, and then the subsequent control strategy corresponding to the driving road surface of the vehicle can be further executed to control the braking end of the vehicle. Usually, the first slip ratio threshold is greater than the second slip ratio threshold, and the first angular acceleration threshold is greater than the second angular acceleration threshold.

[0191] Of course, the above are only several implementation schemes for determining whether to activate the anti-lock braking system of the vehicle depending on the slip ratio and / or angular acceleration of the braking end. It is also feasible to determine whether to activate the anti-lock braking system of the vehicle by other means. This embodiment of the present application does not limit this. Any method that can determine whether there is a locking phenomenon at the braking end to control the activation of the anti-lock braking system of the vehicle is within the scope claimed in the present application.

[0192] On the basis described above, when the anti-lock braking system of the vehicle is not activated, the present application also provides another corresponding braking control process to better control the braking end. Specifically, the braking control method further includes:

[0193] When the anti-lock braking system of the vehicle is not activated, distribute the braking torque corresponding to the braking command to each braking end of the vehicle, so as to control each braking end according to the distributed braking torque corresponding to each braking end.

[0194] In this embodiment, when the anti-lock braking system of the vehicle is not activated, that is, when there is no locking phenomenon at the braking end, the conventional braking process can be enabled. That is, under the condition of meeting the corresponding regulations and standards, distribute the braking torque corresponding to the braking command to the braking end of the vehicle, so as to control each braking end according to the distributed braking torque corresponding to each braking end.

[0195] Among them, considering that the regenerative braking provided by the motor can be used to improve the energy recovery rate. Therefore, as a feasible embodiment of the present application, in the process of distributing the braking torque to the braking end of the vehicle, under the condition of meeting the relevant regulations and standards, the braking torque can be provided as much as possible by the electric braking system of the rear axle braking end. At the same time, for safety, in the process of providing the braking torque by the electric braking system of the rear axle braking end, it can also be judged at all times whether the braking torque distributed to the rear axle braking end exceeds the total maximum allowable feedback torque that can be provided by the two rear axle motors. Thus, when the distributed braking torque at the braking end exceeds the maximum allowable feedback torque, control the braking end according to the maximum allowable feedback torque, and further distribute the insufficient braking torque to the remaining braking ends, so as to control the remaining braking ends according to the adjusted distributed braking torque.

[0196] In order to clearly understand the complete control process of the braking control method provided by the embodiments of the present application, the following will be combined with the foregoing Figures 1 to 7 The content provided, provide a complete implementation process of the braking control method. Please refer to Figure 8a , Figure 8a which is a flowchart of a braking control method provided by an embodiment of the present application, specifically including the following steps:

[0197] Step S01, during the driving of the vehicle, collect and obtain vehicle state parameters such as the depth of the brake pedal, wheel speed, estimated vehicle speed, slip ratio, and wheel angular acceleration in real time, and collect braking state parameters such as the actual pressure of the master cylinder, the estimated pressure of each slave cylinder, the control state of each slave cylinder, and the actual torque of the motor.

[0198] Step S02: During the vehicle braking process, it is constantly determined whether the wheel slip rate and wheel angular acceleration meet the ABS activation threshold. If they do, ABS control is initiated, i.e., step S06 is executed; if not, conventional braking is initiated, i.e., step S03 is executed;

[0199] Step S03: The rear axle dual motors provide braking torque as much as possible while meeting regulatory requirements; and a constant determination is made as to whether the braking torque allocated to the rear axle exceeds the sum of the maximum allowable feedback torques of the rear axle dual motors.

[0200] Step S04: If the braking torque allocated to the rear axle exceeds the sum of the maximum allowable regenerative torques of the rear axle dual motors, the shortfall in the rear axle is supplemented by the front axle hydraulic pressure, i.e., the newly added hydraulic braking torque of the front axle is equal to the braking torque allocated to the rear axle minus the sum of the maximum allowable regenerative torques of the rear axle dual motors;

[0201] Step S05: If the braking torque allocated to the rear axle does not exceed the maximum allowable sum of the feedback torques of the rear axle dual motors, the braking torque allocated to the rear axle is entirely implemented by the feedback torques of the rear axle dual motors, and the front axle pure hydraulic pressure still implements the target hydraulic pressure according to the braking torque allocated to the front axle;

[0202] Step S06: When the ABS is activated, the road surface recognition module is entered, and the road surface is divided into uniform high-adhesion, uniform low-adhesion, split road surface, high-to-low connecting road surface, and low-to-high connecting road surface;

[0203] Step S07, determining whether the current road surface is a uniform road surface;

[0204] Step S08, determining whether the current road surface is a split road surface;

[0205] Step S09, determining whether the current road surface is a high-to-low butting road surface;

[0206] Step S10, determining whether the current road surface is a uniform low-adhesion road surface, if so, entering low-adhesion control, otherwise entering low-adhesion control;

[0207] Step S11: When the road surface is identified as a uniform low-adhesion road surface, the low-adhesion road surface control logic is entered, that is, the front axle is controlled based on the slip rate, and the rear axle is also controlled based on the slip rate;

[0208] Step S12: When the uniform road surface is identified as a non-low-adhesion road surface, the high-adhesion road surface control logic is entered, that is, the front axle is controlled based on angular acceleration, and the rear axle is controlled based on slip rate;

[0209] Step S13: When the road surface is identified as a split road, the split road control logic is entered, that is, the front axle is controlled based on the slip rate, and the rear axle is also controlled based on the slip rate, but the torque deviation is controlled within a certain range;

[0210] Step S14: When the road surface is identified as a high-to-low contact road surface, the front axle is depressurized and then controlled based on the slip ratio, and the rear axle is quickly torque-reduced and then controlled based on the slip ratio;

[0211] In step S15, when the road surface is identified as a low-to-high contact road surface, the front axle is pressurized and then controlled based on angular acceleration, and the rear axle is quickly torqued and then controlled based on slip rate.

[0212] The Y / N shown in the figure represents yes / no under the corresponding judgment logic.

[0213] For the control strategies corresponding to different road conditions, please refer to Figures 8b to 8f shown.

[0214] like Figure 8b , which is a flow chart of the braking control strategy on a uniform low-adhesion road surface, specifically, includes steps S111 to S113:

[0215] Step S111: When the road surface is identified as a low-adhesion condition, the low-adhesion control logic is entered.

[0216] Specifically, when the road surface recognition module identifies a low-adhesion condition, both the front and rear axles enter the low-adhesion control logic;

[0217] In step S112, the front axle enters the pure hydraulic low-select control logic, and the rear axle enters the distributed motor regenerative braking independent control.

[0218] Specifically, the pure hydraulic braking of the front axle enters the low-selection control logic, and the pure electric braking of the rear axle enters the independent control logic.

[0219] In step S113 , the front axle performs feedback adjustment based on the optimal slip ratio, and the dual motors on the rear axle also perform feedback adjustment based on the optimal slip ratio.

[0220] Specifically, the optimal slip rate is obtained based on the road adhesion coefficient, and the deviation between the average actual slip rate of the two wheels on the front axle and the optimal slip rate is used as the control target. The required target master wheel cylinder pressure is calculated through the PID controller to adjust the front axle hydraulic braking force; the rear axle enters independent control, and the deviation between the actual slip rate of each wheel and the optimal slip rate is used as the control target, and the target feedback torque is calculated through the PID controller.

[0221] like Figure 8c , which is a flow chart of the braking control strategy on a uniform high-adhesion road surface, specifically, includes steps S121 to S123:

[0222] Step S121: When the road surface is identified as a high-adhesion working condition, the high-adhesion control logic is entered.

[0223] Specifically, when the road surface recognition module identifies a high-adhesion working condition, both the front and rear axles enter the high-adhesion control logic;

[0224] Step S122: The front axle enters the pure hydraulic independent control logic, and the rear axle enters the distributed motor regenerative braking independent control.

[0225] Specifically, the pure hydraulic braking of the front axle enters the independent control logic, and the pure electric motor braking of the rear axle enters the independent control logic.

[0226] Step S123: The front axle is adjusted based on the logical threshold method, and the dual motors of the rear axle are feedback-adjusted based on the optimal slip ratio.

[0227] Specifically, the target pressure of the master cylinder is calculated by subtracting the actual torque of the distributed dual motors of the rear axle from the total target braking torque demanded by the driver. The two front wheels respectively enter the threshold control logic with the wheel angular acceleration as the main threshold and the slip ratio as the auxiliary threshold, and decide the control states (pressure increase, pressure reduction, pressure holding) of the two wheel cylinders, as well as the corresponding pressure increase rate, pressure holding time, and target pressure relief amount, so as to control the wheels near the optimal slip ratio; the dual motors of the rear axle respectively take the deviation between their actual slip ratio and the optimal slip ratio as the control target, and calculate the target feedback torque through the PID controller.

[0228] As Figure 8d shown, it is a schematic flow diagram of the braking control strategy under the split road surface. Specifically, it includes steps S131 to S133:

[0229] Step S131: When the road surface is recognized as the split working condition, enter the split control logic.

[0230] Specifically, when the road surface recognition module recognizes the split working condition, the front axle enters the low-selection control logic, and the rear axle enters the independent control within the torque deviation limit range.

[0231] Step S132: The front axle enters the pure hydraulic low-selection control logic, and the rear axle enters the distributed motor regenerative braking independent control.

[0232] Specifically, the pure hydraulic braking of the front axle enters the low-selection control logic, and the pure electric motor braking of the rear axle enters the independent control logic within the torque deviation limit range.

[0233] Step S133: The front axle is feedback-adjusted based on the optimal slip ratio, and the dual motors of the rear axle are also feedback-adjusted based on the optimal slip ratio.

[0234] Specifically, for the front axle's pure hydraulic low-selection control logic, the master cylinder is connected to the outrigger cylinders, that is, the pressure-increasing valve is fully open. Only by adjusting the target pressure of the master cylinder can the hydraulic pressure of the two outrigger cylinders be adjusted. Taking the deviation between the average actual slip ratio of the two front wheels and the optimal slip ratio as the control target, the target pressure of the master cylinder is calculated in real time through a PID controller. The target pressure of the master wheel cylinder is limited by the deviation between the driver's required braking torque and the actual torque of the rear axle's dual motors; for the rear axle's dual motors, the deviation between their respective actual slip ratios and the optimal slip ratio is used as the control target, and the target feedback torque is calculated through a PID controller. When the target torque deviation exceeds the threshold value, the target torque of the larger motor is taken as the target torque of the smaller motor plus the deviation threshold value.

[0235] As Figure 8e shown, it is a schematic diagram of the process for the high-adhesion to low-adhesion docking road surface. Specifically, it includes steps S141 to S143:

[0236] Step S141, when the road surface is recognized as a high-to-low condition, enter the high-to-low docking control logic.

[0237] Specifically, when the road surface recognition module recognizes a high-to-low docking condition, the front axle enters the low-adhesion control logic, and after the rear axle quickly reduces torque, it also enters the low-adhesion control logic.

[0238] Step S142, the front axle enters the low-adhesion control logic, and the rear axle quickly reduces torque and enters the independent control of distributed motor regenerative braking.

[0239] Specifically, after the front axle's pure hydraulic system enters the pressure relief state, it enters the low-adhesion low-selection control logic. After the rear axle's pure electric motor braking quickly reduces torque, it enters the low-adhesion independent control logic.

[0240] Step S143, the outrigger cylinders of the front axle enter the pressure relief stage and the pressure of the master wheel cylinder is feedback-regulated based on the low-adhesion optimal slip ratio. The rear axle's dual motors also perform feedback regulation based on the optimal slip ratio.

[0241] Specifically, before the front axle transitions from high adhesion to low adhesion, the front axle will enter a continuous pressure relief stage for a period of time. The master cylinder is connected to the two outrigger cylinders to ensure reducing the time when the slip ratio of the front wheels is too high after reaching low adhesion. When the slip ratio returns to the threshold value, it enters the low-adhesion low-selection control logic. Taking the deviation between the average actual slip ratio of the two front axle wheels and the optimal slip ratio as the control target, the required target pressure of the master wheel cylinder is calculated through a PID controller to adjust the hydraulic braking force of the front axle; the rear axle determines to enter the low-adhesion condition based on the control state of the front axle and the road surface adhesion recognition module. The rear axle's dual motors both enter the rapid torque reduction state. When the torque drops to a certain threshold, observe whether the wheel slip ratio is lower than the threshold value. When the slip ratio is lower than the threshold value, enter the rear axle low-adhesion independent control logic, taking the deviation between the actual slip ratio and the optimal slip ratio of each wheel as the control target, and calculating the target feedback torque through a PID controller.

[0242] As Figure 8f shown, it is a schematic diagram of the step process for docking the road surface from low adhesion to high adhesion. Specifically, it includes steps S151 to S153:

[0243] Step S151, when the road surface is recognized as a low-to-high working condition, enter the low-to-high docking control logic.

[0244] Specifically, when the road surface recognition module recognizes a low-to-high docking working condition, the front axle enters the high-adhesion control logic, and after the rear axle quickly increases the torque, it also enters the high-adhesion control logic.

[0245] Step S152, the front axle enters the high-adhesion control logic, and the rear axle quickly increases the torque and enters the independent control of distributed motor regenerative braking.

[0246] Specifically, after the front axle enters the supercharging state by pure hydraulics, it enters the high-adhesion independent control logic, and after the rear axle quickly increases the torque by pure electric braking, it enters the high-adhesion independent control logic;

[0247] Step S153, the front axle support wheel cylinder enters the supercharging stage and the main wheel cylinder enters the supercharging stage, and the two front wheels are independently controlled. The rear axle dual motors also perform feedback regulation based on the optimal slip ratio.

[0248] Specifically, before the front axle enters the process from low adhesion to high adhesion, the front axle will enter a continuous supercharging stage for a period of time. The master cylinder is connected to the two support wheel cylinders to ensure reducing the deceleration recovery time from low adhesion to high adhesion. When the master cylinder pressure reaches a certain threshold value or the slip ratio starts to increase, then enter the high-adhesion independent control logic. Using the wheel angular acceleration as the main threshold value and the slip ratio as the auxiliary threshold value for the threshold value control logic, determine the control states (supercharging, decompression, pressure holding) of the two support wheel cylinders, as well as the corresponding supercharging rate, pressure holding time, and target pressure relief amount, and control the wheels near the optimal slip ratio; The rear axle determines to enter the high-adhesion working condition according to the control state of the front axle and the road surface adhesion recognition module. The rear axle dual motors both enter the rapid torque increase state. When the torque increases to a certain threshold value, observe whether the wheel slip ratio starts to increase. When the slip ratio starts to increase, enter the high-adhesion independent control logic of the rear axle. Respectively, use the deviation between the actual slip ratio of each wheel and the optimal slip ratio as the control target, and calculate the target feedback torque through a PID controller. The actual torque of the motor and the braking torque generated by the actual pressure of the master cylinder do not exceed the driver's required braking torque during the whole process.

[0249] The above has elaborated in detail on various road surface working conditions, the selection control strategies under various road surface working conditions, and the corresponding braking control effects. Through the driving road surface, the present application can perform braking control on at least two braking ends, enabling multiple braking ends to adopt the same or different braking strategies corresponding to the driving road surface respectively, so that each braking end can be in a better working condition that meets the current driving road surface, thereby achieving precise braking of the vehicle and improving the braking control effect of the vehicle.

[0250] In order to better implement a braking control method provided by the present application, please refer to Figure 9 , Figure 9 which is a schematic structural diagram of a distributed vehicle electro-hydraulic composite anti-lock braking control system for implementing the above braking control method provided by an embodiment of the present application. Specifically, in the distributed vehicle electro-hydraulic composite anti-lock braking control system, it includes:

[0251] Left front brake caliper assembly 1, body electronic stability program ESP2, front motor assembly and FMCU 3, right front brake caliper assembly 4, brake pedal travel sensor 5, accelerator pedal travel sensor 6, left front wheel speed sensor 7, right front wheel speed sensor 8, steering wheel angle sensor 9, electric power steering system 10, gear position controller 11, electronic parking controller 12, vehicle controller 13, battery management system 14, yaw rate sensor 15, left rear wheel speed sensor 16, left rear motor assembly and RLMCU 17, right rear motor assembly and RRMCU 18, right rear wheel speed sensor 19.

[0252] Among them, in this application, the vehicle controller 13 is connected to the accelerator pedal travel sensor 6, left front wheel speed sensor 7, right front wheel speed sensor 8, left rear wheel speed sensor 16, and right rear wheel speed sensor 19 through hard wires. The vehicle controller 13 then analyzes the hard wire signals to obtain the accelerator pedal depth signal and four-wheel speed signals. The vehicle controller 13 communicates with the Electronic Stability Program (ESP) 2 of the vehicle body through the braking subnet to obtain signals such as the brake pedal travel, actual master cylinder pressure, estimated wheel cylinder pressure, and actual states of each solenoid valve. The ESP 2 of the vehicle body obtains signals such as the target master cylinder pressure, control states of each wheel cylinder, target boost rate, and target pressure relief amount sent by the vehicle controller 13 through the braking subnet. The vehicle controller 13 communicates with the gear controller 11 through CAN signals to obtain the current gear state of the vehicle. The vehicle controller 13 communicates with the Electric Power Steering (EPS) system 10 through CAN signals to obtain the steering wheel angle. The vehicle controller 13 communicates with the Electronic Parking Brake (EPB) controller 12 through CAN signals to obtain whether the vehicle is in the parking state. The vehicle controller 13 communicates with the yaw rate sensor 15 through the yaw rate subnet to obtain signals such as the vehicle's longitudinal acceleration signal, lateral acceleration signal, and yaw rate signal. The vehicle controller 13 communicates with the Battery Management System (BMS) 14 through CAN signals to obtain signals such as the state of charge of the battery, maximum allowable charging power, and maximum allowable discharging power. The vehicle controller 13 communicates with the front motor assembly and FMCU 3, left rear motor assembly and RLMCU 17, and right rear motor assembly and RRMCU 18 through the power subnet to obtain signals such as the maximum torque capacity of the motor, actual motor torque, and motor speed, and sends the target torque of the front motor calculated by the vehicle controller to the front motor controller to achieve the purpose of electric braking or driving.

[0253] In the distributed vehicle electro-hydraulic composite anti-lock braking control system provided by this application:

[0254] Brake caliper assemblies (including the left front brake caliper assembly 1 and the right front brake caliper assembly 4): used to execute hydraulic braking force to decelerate the wheels;

[0255] Wheel speed sensors (including the left front wheel speed sensor 7, right front wheel speed sensor 8, left rear wheel speed sensor 16, and right rear wheel speed sensor 19): used to measure the wheel speeds of the four wheels;

[0256] Brake pedal travel sensor 5: used to measure the depth of the brake pedal and is connected to the ESP 2 of the vehicle body through a hard wire. The ESP 2 of the vehicle body analyzes the brake pedal travel and sends this signal to the vehicle controller 13 through the braking subnet;

[0257] Accelerator pedal travel sensor 6: It is used to measure the depth of the accelerator pedal and is connected to the vehicle controller 13 by hard wire. The vehicle controller analyzes the accelerator pedal travel signal and sends it to the CAN bus;

[0258] Electric power steering system 10: It obtains the driver's steering intention through the steering angle and torque sensors, and controls the steering motor according to the actual situation to achieve steering;

[0259] Steering wheel angle sensor 9: It collects the current rotation angle of the steering wheel;

[0260] Vehicle controller 13: It collects the hard wire signals of the wheel speed sensors, processes them into CAN signals and sends them to the CAN bus; it collects the longitudinal acceleration signal, lateral acceleration signal and yaw rate signal in the yaw rate sensor, and combines the wheel speed sensor signals and steering wheel angle signals to estimate vehicle speed, slope, slip ratio, wheel angular acceleration, etc. The ABS control module is integrated in the vehicle controller 13 to decide the master cylinder target pressure, the control states of each wheel cylinder, the boost rate, the target pressure relief amount, the motor target torque, etc.;

[0261] Yaw rate sensor 15: It is used to measure the vehicle longitudinal acceleration, lateral acceleration and yaw rate signals, and sends them to the vehicle controller 13 through the braking subnet;

[0262] Electronic parking controller 12: It is used to realize static or dynamic parking of the vehicle, and sends the current parking state of the vehicle to each controller;

[0263] Battery management system 14: It is used to manage the charging and discharging of power batteries or supercapacitors, and sends signals such as the current maximum allowable charging power and maximum allowable discharging power to the vehicle controller 13, the front motor controller 3, the left rear motor controller 17, and the right rear motor controller 18;

[0264] Electronic stability program ESP2: It is used to execute the master cylinder target pressure, the boost-hold-deceleration control commands of each wheel cylinder sent by the VCU, and sends the actual pressure of the master cylinder, the actual states of each solenoid valve, and the estimated pressure of each wheel cylinder to the vehicle controller 13 through the braking subnet;

[0265] Gear controller 11: It collects the driver's gear demand, and combines other vehicle information to execute gear shifting, and sends the current gear information to the vehicle controller 13;

[0266] Front motor assembly and FMCU 3: It is used to execute the motor target torque of the vehicle controller, and feedback signals such as the actual torque and wheel speed of the motor to the vehicle controller 13;

[0267] Left rear motor assembly and RLMCU 17: It is used to execute the motor target torque of the vehicle controller and feedback signals such as the actual motor torque and wheel speed to the vehicle controller 13;

[0268] Right rear motor assembly and RRMCU 18: It is used to execute the motor target torque of the vehicle controller and feedback signals such as the actual motor torque and wheel speed to the vehicle controller 13.

[0269] Figure 10 Block diagram of an electronic device 1000 shown according to an exemplary embodiment. As Figure 10 shown, the electronic device 1000 may include: a processor 1001, a memory 1002. The electronic device 1000 may further include one or more of a multimedia component 1003, an input / output (I / O) component 1004, and a communication component 1005. In this embodiment, the electronic device 1000 may be an integrated device to implement the braking control method provided in this embodiment.

[0270] Among them, the processor 1001 is used to control the overall operation of the electronic device 1000 to complete all or part of the steps in the above-mentioned braking control method. The memory 1002 is used to store various types of data to support the operation of the electronic device 1000. These data may include, for example, instructions for any application or method operating on the electronic device 1000, as well as application-related data, such as contact data, sent and received messages, pictures, audio, video, and so on. The memory 1002 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Read-Only Memory (PROM), Read-Only Memory (ROM), magnetic memory, flash memory, magnetic disk or optical disc. The multimedia component 1003 may include a screen and an audio component. Among them, the screen can be, for example, a touch screen, and the audio component is used to output and / or input audio signals. For example, the audio component may include a microphone, and the microphone is used to receive external audio signals. The received audio signal can be further stored in the memory 1002 or sent through the communication component 1005. The audio component also includes at least one speaker for outputting audio signals. The I / O component 1004 provides an interface between the processor 1001 and other interface modules, and the above-mentioned other interface modules can be a keyboard, a mouse, buttons, etc. These buttons can be virtual buttons or physical buttons. The communication component 1005 is used for wired or wireless communication between the electronic device 1000 and other devices. Wireless communication, such as Wi-Fi, Bluetooth, Near Field Communication (NFC), 2G, 3G, 4G, NB-IOT, eMTC, or other 5G, etc., or a combination of one or more of them, is not limited here. Therefore, the corresponding communication component 1005 may include: a Wi-Fi module, a Bluetooth module, an NFC module, and so on.

[0271] In an exemplary embodiment, the electronic device 1000 can be implemented by one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors or other electronic components, and is used to execute the above-mentioned braking control method.

[0272] An embodiment of the present application further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements the braking control method provided in any of the above embodiments.

[0273] An embodiment of the present application further provides a computer program product, which includes a computer program. When the computer program is executed by a processor, the computer program product implements the braking control method provided in any of the above embodiments when executed.

[0274] The present application also provides a vehicle, on which the above-mentioned electronic device is provided.

[0275] In one embodiment, the vehicle can be configured in a fully or partially autonomous driving mode. For example, the vehicle can control itself while in the autonomous driving mode, and can determine the current state of the vehicle and its surrounding environment through manual operation, determine the possible behaviors of at least one other vehicle in the surrounding environment, and determine the confidence level corresponding to the possibility of the other vehicle performing the possible behaviors, and control the vehicle based on the determined information. When the vehicle is in the autonomous driving mode, the vehicle can be set to operate without interacting with people.

[0276] The vehicle may further include various subsystems, such as a traveling system, a sensor system control system, one or more peripheral devices, as well as a power supply, a computer system, and a user interface. Optionally, the vehicle may include more or fewer subsystems, and each subsystem may include multiple components. For example, each subsystem includes multiple ECUs (electronic control units, i.e., vehicle computers).

[0277] In addition, each subsystem and component of the vehicle can be interconnected by wire or wirelessly.

[0278] The propulsion system may include components that provide powered movement for the vehicle. In one embodiment, the propulsion system may include an engine, an energy source, a transmission, and wheels / tires. The engine can be an internal combustion engine, an electric motor, an air compression engine, or a combination of other types of engines, such as a hybrid engine composed of a gasoline engine and an electric motor, or a hybrid engine composed of an internal combustion engine and an air compression engine. The engine converts energy into mechanical energy.

[0279] Examples of energy sources include gasoline, diesel, other petroleum-based fuels, propane, other compressed gas-based fuels, ethanol, solar panels, batteries, and other power sources. The energy source can also provide energy for other systems of the vehicle.

[0280] The transmission can transfer the mechanical power from the engine to the wheels. The transmission may include a gearbox, a differential, and a drive shaft. In one embodiment, the transmission may also include other devices, such as a clutch. Among them, the drive shaft may include one or more shafts that can be coupled to one or more wheels.

[0281] The sensor system may include several sensors that sense information about the environment around the vehicle. For example, the sensor system may include a positioning system (the positioning system can be a GPS system, a Beidou system, or other positioning systems), an inertial measurement unit (IMU), a radar, a lidar, and a camera. The sensor system may also include sensors for monitoring the internal systems of the vehicle being monitored (e.g., in-vehicle air quality monitor, fuel gauge, engine oil temperature gauge, etc.). Sensor data from one or more of these sensors can be used to detect objects and their corresponding characteristics (position, shape, orientation, speed, etc.). Such detection and identification are key functions for the safe operation of autonomous vehicles.

[0282] The positioning system can be used to estimate the geographical location of the vehicle. The IMU is used to sense changes in the position and orientation of the vehicle based on inertial acceleration. In one embodiment, the IMU can be a combination of an accelerometer and a gyroscope.

[0283] The radar can use radio signals to sense objects within the surrounding environment of the vehicle. In some embodiments, in addition to sensing objects, the radar can also be used to sense the speed and / or forward direction of the objects.

[0284] The lidar can use lasers to sense objects in the environment where the vehicle is located. In some embodiments, the lidar may include one or more laser sources, a laser scanner, and one or more processing modules, as well as other system components.

[0285] The camera can be used to capture multiple images of the surrounding environment of the vehicle. The camera can be a static camera or a video camera.

[0286] The control system is for controlling the operation of a vehicle and its components. The control system may include various elements, including a steering system, an accelerator, a braking unit, a computer vision system, a route control system, and an obstacle avoidance system.

[0287] The steering system is operable to adjust the forward direction of the vehicle. For example, in one embodiment, it may be a steering wheel system.

[0288] The accelerator is used to control the operating speed of the engine and thereby control the speed of the vehicle.

[0289] The braking unit is used to control the deceleration of the vehicle. The braking unit may use friction to slow down the wheels.

[0290] In other embodiments, the braking unit may convert the kinetic energy of the wheels into electric current. The braking unit may also take other forms to slow down the rotational speed of the wheels so as to control the speed of the vehicle.

[0291] The computer vision system is operable to process and analyze images captured by a camera to identify objects and / or features in the vehicle's surrounding environment. The objects and / or features may include traffic signals, road boundaries, and obstacles. The computer vision system may use object recognition algorithms, Structure from Motion (SFM) algorithms, video tracking, and other computer vision techniques. In some embodiments, the computer vision system may be used to map the environment, track objects, estimate the speed of objects, and so on.

[0292] The route control system is used to determine the driving route of the vehicle. In some embodiments, the route control system may combine data from GPS and one or more pre - determined maps to determine the driving route for the vehicle.

[0293] The obstacle avoidance system is used to identify, evaluate, and avoid or otherwise cross potential obstacles in the vehicle's environment.

[0294] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of this application, "a plurality" means two or more unless otherwise specifically defined.

[0295] In the above embodiments, the descriptions of the respective embodiments have their own emphases. For parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0296] In the embodiments, implementation manners and related technical features of the present application, they can be combined and replaced with each other without conflict.

[0297] The above are only the preferred embodiments of the present application, and do not impose any formal restrictions on the present application. However, any simple modifications, equivalent changes and decorations made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application still fall within the scope of the technical solution of the present application.

Claims

1. A braking control method, characterized in that, Including: Performing braking control on at least two braking ends according to the driving road surface.

2. The method according to claim 1, wherein The driving road surface includes at least one of a uniform road surface, an oncoming road surface, and a butt-joint road surface, and the braking ends include a front axle braking end and a rear axle braking end.

3. The method according to claim 1, wherein The at least two braking ends are in contact with the driving road surface.

4. The method according to any one of claims 1 to 3, characterized in that The performing braking control on at least two braking ends according to the driving road surface includes: When the driving road surface is a uniform road surface, performing braking control on any one or more of the at least two braking ends.

5. The method according to claim 4, wherein When the driving road surface is a uniform road surface, performing braking control on the rear axle according to the braking yaw parameter of the rear axle braking end, and / or performing braking control on the front axle according to the braking yaw parameter of the front axle braking end.

6. The method according to claim 5, wherein The braking yaw parameter includes at least one of vehicle speed, slope, slip ratio, and angular acceleration.

7. The method according to claim 5, wherein The braking yaw parameter is obtained from the yaw parameter and the braking end motion parameter.

8. The method according to claim 5, characterized in that The performing braking control on the rear axle according to the braking yaw parameter of the rear axle braking end includes: Performing braking control on the rear axle according to the slip ratio of the rear axle braking end.

9. The method according to claim 8, characterized in that, The performing braking control on the rear axle according to the slip ratio of the rear axle braking end includes: Determining the braking torque of the rear axle according to the deviation between the actual slip ratio and the optimal slip ratio of the rear axle braking end to perform braking control on the rear axle.

10. The method according to claim 5, wherein The performing braking control on the front axle according to the braking yaw parameter of the front axle braking end includes: Performing braking control on the front axle according to the slip ratio and / or angular acceleration of the front axle braking end.

11. The method according to claim 10, wherein The performing braking control on the front axle according to the slip ratio and / or angular acceleration of the front axle braking end includes: When the driving road surface is a low-adhesion uniform road surface, performing braking control on the front axle according to the slip ratio of the front axle braking end; and / or When the driving road surface is a high-adhesion uniform road surface, performing braking control on the front axle according to the angular acceleration of the front axle braking end.

12. The method according to claim 11, wherein The road adhesion coefficient of the low-adhesion uniform road surface is lower than that of the high-adhesion uniform road surface.

13. The method according to claim 11, characterized in that, The performing braking control on the front axle according to the slip ratio of the front axle braking end includes: Performing braking control on the front axle according to the deviation between the actual slip ratio and the optimal slip ratio of the front axle braking end.

14. The method according to claim 13, wherein The performing braking control on the front axle according to the deviation between the actual slip ratio and the optimal slip ratio of the front axle braking end includes: Determining the wheel cylinder pressure of the target master cylinder according to the deviation between the actual slip ratio and the optimal slip ratio of the front axle braking end to perform braking control on the front axle through the hydraulic braking force provided by the target master cylinder.

15. The method according to claim 11, wherein The performing braking control on the front axle according to the angular acceleration of the front axle braking end includes: Determining the wheel cylinder parameter of the wheel cylinder corresponding to the front axle braking end according to the angular acceleration of the front axle braking end to perform braking control on the front axle.

16. The method according to claim 15, characterized in that There are multiple front axle braking ends; the determining the wheel cylinder parameter of the wheel cylinder corresponding to the front axle braking end according to the angular acceleration of the front axle braking end to perform braking control on the front axle includes: Respectively determining the wheel cylinder parameter of the branch wheel cylinder corresponding to each front axle braking end according to the actual angular acceleration of each front axle braking end to perform braking control on the front axle.

17. The method according to any one of claims 1 to 3, characterized in that, The performing braking control on at least two braking ends according to the driving road surface includes: When the driving road surface is a two-way road surface, the rear axle is braked according to the slip ratio of the rear axle braking end, and / or the front axle is braked according to the slip ratio of the front axle braking end.

18. The method according to claim 17, wherein There are multiple rear axle braking ends; The braking control of the rear axle according to the slip ratio of the rear axle braking end includes: According to the deviation between the actual slip ratio and the optimal slip ratio of each rear axle braking end, the braking torque of each rear axle braking end is determined respectively to brake the rear axle.

19. The method according to claim 18, wherein During the process of braking the rear axle, the torque difference between the braking torques of the multiple rear axle braking ends does not exceed a preset torque threshold.

20. The method according to claim 19, wherein The rear axle braking end includes a first rear axle braking end and a second rear axle braking end, and the method further includes: If the first braking torque of the first rear axle braking end exceeds the sum of the second braking torque of the second rear axle braking end and the preset torque threshold, the first braking torque is adjusted to the sum of the second braking torque and the preset torque threshold.

21. The method according to any one of claims 1 to 3, characterized in that, The braking control of at least two braking ends according to the driving road surface includes: When the driving road surface is a docking road surface, adjust the braking torque of the rear axle braking end until the slip ratio of the rear axle braking end meets the preset working condition, and then brake the rear axle according to the slip ratio of the rear axle braking end; and / or adjust the hydraulic braking force of the front axle braking end until the slip ratio of the front axle braking end meets the preset working condition, and then brake the front axle according to the slip ratio and / or angular acceleration of the front axle braking end.

22. The method according to claim 21, wherein The docking road surface includes at least one of a first docking road surface and a second docking road surface, wherein the adhesion coefficient of the first docking road surface decreases along the driving direction of the vehicle, and the adhesion coefficient of the second docking road surface increases along the driving direction of the vehicle.

23. The method according to claim 22, wherein Adjusting the braking torque of the rear axle braking end includes: When the driving road surface is the first docking road surface, reduce the braking torque of the rear axle braking end, and / or When the driving road surface is the second docking road surface, increase the braking torque of the rear axle braking end.

24. The method according to claim 23, wherein The braking torque of the rear axle braking end is controlled by a rear axle motor.

25. The method according to claim 21, wherein Until the slip ratio of the rear axle braking end meets the preset working condition, braking the rear axle according to the slip ratio of the rear axle braking end includes: When the driving road surface is the first docking road surface, if the slip ratio of the rear axle braking end is lower than the threshold value, brake the rear axle according to the slip ratio of the rear axle braking end; and / or When the driving road surface is the second docking road surface, if the slip ratio of the rear axle braking end increases, brake the rear axle according to the slip ratio of the rear axle braking end.

26. The method according to claim 21, wherein Adjusting the hydraulic braking force of the front axle braking end includes: When the driving road surface is the first docking road surface, reduce the hydraulic braking force of the front axle braking end; and / or When the driving road surface is the second docking road surface, increase the hydraulic braking force of the front axle braking end.

27. The method according to claim 26, wherein, The hydraulic braking force of the front axle braking end is provided by a target master cylinder.

28. The method according to claim 21, wherein Until the slip ratio of the front axle braking end meets the preset working condition, braking the front axle according to the slip ratio and / or angular acceleration of the front axle braking end includes: When the driving road surface is the first docking road surface, if the slip ratio of the front axle braking end is lower than the threshold value, the front axle is braked and controlled according to the slip ratio of the front axle braking end; and / or When the driving road surface is the second docking road surface, if the slip ratio of the front axle braking end increases, the front axle is braked and controlled according to the angular acceleration of the front axle braking end.

29. The method according to any one of claims 1 to 28, characterized in that The method further includes: Determining the driving road surface of the vehicle according to the ground adhesion coefficient of each braking end of the vehicle.

30. The method according to claim 29, wherein The determining the driving road surface of the vehicle according to the ground adhesion coefficient of each braking end of the vehicle includes: When the ground adhesion coefficient of each braking end of the vehicle is less than a preset first adhesion coefficient threshold, determining that the driving road surface of the vehicle is a low-adhesion uniform road surface; and / or When the ground adhesion coefficient of each braking end of the vehicle is greater than a preset second adhesion coefficient threshold, determining that the driving road surface of the vehicle is a high-adhesion uniform road surface.

31. The method according to claim 29, wherein The determining the driving road surface of the vehicle according to the ground adhesion coefficient of each braking end of the vehicle includes: When the ground adhesion coefficient of the front axle braking end of the vehicle is less than a preset third adhesion coefficient threshold and the ground adhesion coefficient of the rear axle braking end is greater than a preset fourth adhesion coefficient threshold, determining that the driving road surface of the vehicle is the first docking road surface; and / or When the ground adhesion coefficient of the rear axle braking end of the vehicle is less than a preset third adhesion coefficient threshold and the ground adhesion coefficient of the front axle braking end is greater than a preset fourth adhesion coefficient threshold, determining that the driving road surface of the vehicle is the second docking road surface.

32. The method according to claim 29, wherein The determining the driving road surface of the vehicle according to the ground adhesion coefficient of each braking end of the vehicle includes: In the case where the ratio between the ground adhesion coefficients of the first front axle braking end and the second front axle braking end among the front axle braking ends is greater than a preset ratio threshold, and / or, in the case where the ratio between the ground adhesion coefficients of the first rear axle braking end and the second rear axle braking end among the rear axle braking ends is greater than a preset ratio threshold, determining that the driving road surface of the vehicle is a split road surface.

33. The method according to claim 29, wherein The ground adhesion coefficient of each braking end of the vehicle is determined through the following steps: Determining the braking torque, load, slip ratio, and angular acceleration of each braking end; Determining the ground adhesion coefficient of each braking end according to the braking torque, load, slip ratio, and angular acceleration of each braking end.

34. The method according to any one of claims 1 to 33, characterized in that, The front axle braking end includes the front wheels of the vehicle, and the rear axle braking end includes the rear wheels of the vehicle.

35. The method according to any one of claims 1 to 34, characterized in that, The method further includes: When the anti-lock braking system of the vehicle is activated, performing the step of braking and controlling at least two braking ends according to the driving road surface.

36. The method according to claim 35, wherein The method further includes: Determining whether to activate the anti-lock braking system of the vehicle according to the slip ratio and / or angular acceleration of the braking end during the vehicle braking process.

37. The method according to claim 35, characterized in that, The method further includes: When the anti-lock braking system of the vehicle is not activated, distributing the braking torque corresponding to the braking instruction to each braking end of the vehicle to control each braking end according to the distributed braking torque corresponding to each braking end.

38. The method according to claim 37, wherein The method further includes: In the case where the allocated braking torque of the target braking end exceeds the maximum allowable feedback torque, controlling the target braking end according to the maximum allowable feedback torque; and Based on the difference between the allocated braking torque of the target braking end and the maximum allowable feedback torque, adjusting the allocated braking torque of the remaining braking ends to control the remaining braking ends according to the adjusted allocated braking torque.

39. A computer-readable storage medium having a computer program stored thereon, characterized in that, The computer-readable storage medium stores instructions that, when executed by a computer, cause the computer to implement the braking control method according to any one of claims 1 to 38.

40. A computer program product, characterized in that, The computer program product stores instructions that, when executed by a computer, cause the computer to implement the braking control method according to any one of claims 1 to 38.

41. An electronic device, characterized in that, Comprising: A memory having stored thereon a computer program; A processor for executing the computer program in the memory to implement the braking control method according to any one of claims 1 to 38.

42. A vehicle, characterized in that, Implementing the braking control method according to any one of claims 1 to 38, or comprising the computer-readable storage medium according to claim 39, or comprising the computer program product according to claim 40, or comprising the electronic device according to claim 41.

Images