Braking force control method and device of hybrid braking system and vehicle

Abstract

The application discloses a brake force control method and device of a hybrid brake system and a vehicle, and belongs to the technical field of vehicle brake control. The brake force control method comprises the following steps: acquiring a total brake force request and vehicle state information; identifying a brake working condition type according to the total brake force request and the vehicle state information; and in the case that the brake working condition type is an emergency brake working condition, distributing brake forces of front wheels and rear wheels of the vehicle according to the total brake force request to control brake forces of the hybrid brake system. In the case of the emergency brake working condition, the brake forces of the front wheels and the rear wheels of the vehicle are distributed according to the total brake force request, and in the case that the brake force of the front wheels of the vehicle is insufficient, the brake force of the rear wheels of the vehicle is supplemented to realize brake force control of the hybrid brake system, meet the demand of the brake force, and guarantee safety.

Description

Technical Field

[0001] This application relates to the field of vehicle braking control technology, specifically to a braking force control method, device, and vehicle for a hybrid braking system. Background Technology

[0002] The braking system is not only a safety component of a vehicle but also a key component in energy management and autonomous driving environments. A vehicle's braking system includes a front-wheel regenerative braking system, a front-wheel hydraulic braking system, and a rear-wheel braking system. The front-wheel regenerative braking system can recover energy while braking to save efficiency. It works in conjunction with the front-wheel hydraulic braking system to distribute the total braking force required. The rear-wheel braking system is a static parking mechanism used when the vehicle is parked.

[0003] In related technologies, vehicles experience high deceleration during emergency braking, resulting in a large demand for total braking force. Relying solely on front wheel regenerative braking systems and front wheel hydraulic braking systems is insufficient to meet this demand. Ordinary rear wheel braking systems only perform static braking and do not support dynamic control of braking force under high deceleration conditions. Consequently, the braking force provided during emergency braking is insufficient, thus affecting vehicle driving safety. Summary of the Invention

[0004] This application provides a braking force control method, device, and vehicle for a hybrid braking system, aiming to solve the problem of insufficient braking force during emergency braking, which affects the safety of vehicle operation.

[0005] In a first aspect, embodiments of this application provide a braking force control method for a hybrid braking system, the braking force control method comprising the following steps:

[0006] Obtain total braking force request and vehicle status information;

[0007] The braking condition type is identified based on the total braking force request and vehicle status information. The braking condition types include normal braking condition, emergency braking condition, and stable critical condition.

[0008] When the braking condition is a normal braking condition or a stable critical condition, a braking force distribution strategy is executed according to the braking condition type to control the braking force of the hybrid braking system.

[0009] When the braking condition is emergency braking, the braking force of the vehicle's front and rear wheels is distributed according to the total braking force request in order to control the braking force of the hybrid braking system.

[0010] In some embodiments, identifying the braking condition type based on the total braking force request and vehicle status information includes:

[0011] The requested deceleration is obtained based on the total braking force request;

[0012] Identify the braking condition type based on the requested deceleration and vehicle status information.

[0013] In some embodiments, vehicle status information includes inertial measurement data;

[0014] The steps for identifying the braking condition type based on the requested deceleration and vehicle status information include:

[0015] If the requested deceleration is less than the first deceleration threshold, the braking condition type is determined to be the normal braking condition.

[0016] If the requested deceleration is greater than the second deceleration threshold, or if an emergency braking signal is received, the braking condition type is determined to be an emergency braking condition.

[0017] Based on the inertial measurement data, the risk of instability is predicted, and the braking condition is determined to be a critical stable condition.

[0018] In some embodiments, the hybrid braking system includes a front wheel regenerative braking system, a front wheel hydraulic braking system, and a rear wheel braking system;

[0019] When the braking condition is emergency braking, the braking force is distributed between the front and rear wheels of the vehicle according to the total braking force request, including:

[0020] Obtain the maximum regenerative braking force of the front wheel regenerative braking system and the maximum hydraulic braking force of the front wheel hydraulic braking system;

[0021] The remaining braking force is determined based on the difference between the total braking force request and the maximum regenerative braking force and the maximum hydraulic braking force;

[0022] The maximum regenerative braking force and the maximum hydraulic braking force are used as the braking force for the front wheels of the vehicle, and the remaining braking force is used as the braking force for the rear wheels of the vehicle. The front wheel regenerative braking system and the front wheel hydraulic braking system brake the front wheels of the vehicle based on the braking force of the front wheels, and the rear wheel braking system brakes the rear wheels of the vehicle based on the braking force of the rear wheels.

[0023] In some embodiments, when the braking condition type is conventional braking condition, a braking force distribution strategy is executed according to the braking condition type, including:

[0024] Obtain the maximum regenerative braking force of the front wheel regenerative braking system;

[0025] When the maximum regenerative braking force is greater than or equal to the total braking force request, the front wheel regenerative braking system is controlled to output a braking force equal to the total braking force request in order to brake the front wheels of the vehicle.

[0026] When the maximum regenerative braking force is less than the total braking force request, the front wheel regenerative braking system is controlled to output braking force at the maximum regenerative braking force, and the front wheel hydraulic braking system outputs braking force equal to the difference between the total braking force request and the maximum regenerative braking force, so as to brake the front wheels of the vehicle.

[0027] In some embodiments, the hybrid braking system further includes a stability function controller; vehicle status information also includes wheel slip ratio and vehicle steering state;

[0028] When the braking condition is a stable critical condition, a braking force distribution strategy is implemented according to the braking condition type, including:

[0029] When the wheel slip ratio tends to exceed the preset slip ratio threshold, or when the vehicle steering state shows a tendency to understeer or oversteer, a coordination signal is sent to the stability function controller so that the stability function controller can take over the control of the power.

[0030] In some embodiments, the control method further includes:

[0031] When the stability function controller is triggered in either normal braking or emergency braking conditions, a coordination signal is sent to the stability function controller so that the stability function controller can take over the control of the braking force.

[0032] In some embodiments, after the stability function controller receives the control of the braking force, the braking force control method further includes:

[0033] Reduce the braking force output by the front wheel regenerative braking system and disengage the front wheel regenerative braking system;

[0034] The braking force output by the front wheel hydraulic braking system and the rear wheel braking system is adjusted according to the control command of the stability function controller.

[0035] Secondly, embodiments of this application also provide a braking force control device for a hybrid braking system, the braking force control device comprising:

[0036] The data acquisition module is used to acquire total braking force requests and vehicle status information;

[0037] The operating condition identification module is used to identify the braking condition type based on the total braking force request and vehicle status information. The braking condition types include normal braking condition, emergency braking condition and stable critical condition.

[0038] The braking force control module is used to execute a braking force distribution strategy according to the braking condition type (normal braking or emergency braking) to control the braking force; and in the case of emergency braking, it distributes the braking force of the front and rear wheels of the vehicle according to the total braking force request to control the braking force.

[0039] Thirdly, embodiments of this application also provide a vehicle, including:

[0040] The hybrid braking system includes a front wheel regenerative braking system, a front wheel hydraulic braking system, a rear wheel braking system, and a stability function controller.

[0041] The braking force control device of the hybrid braking system in the second aspect is connected to the hybrid braking system.

[0042] This application divides braking conditions into normal braking conditions, emergency braking conditions, and stable critical conditions, and adopts different braking strategies for different braking conditions. In the case of emergency braking, the braking force of the front and rear wheels of the vehicle is distributed according to the total braking force request. If the braking force of the front wheels is insufficient, the braking force of the rear wheels is supplemented to achieve braking force control of the hybrid braking system, meet the braking force requirements, and ensure safety. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a schematic flowchart of a braking force control method for a hybrid braking system provided by an exemplary embodiment of this disclosure;

[0045] Figure 2 This is another schematic flowchart of a braking force control method for a hybrid braking system provided by an exemplary embodiment of this disclosure;

[0046] Figure 3 This is a flowchart illustrating step S203 of a braking force control method for a hybrid braking system provided in an exemplary embodiment of this disclosure.

[0047] Figure 4 This is a flowchart illustrating step S204 of a braking force control method for a hybrid braking system provided in an exemplary embodiment of this disclosure.

[0048] Figure 5 This is a schematic diagram of the structure of a braking force control device for a hybrid braking system provided in an exemplary embodiment of this disclosure;

[0049] Figure 6 This is a schematic diagram of the structure of a vehicle provided by an exemplary embodiment of this disclosure;

[0050] Figure 7 This is a schematic diagram of the execution logic of a vehicle braking force control device provided in an exemplary embodiment of this disclosure;

[0051] Figure 8 This is a schematic diagram of the execution logic of a vehicle braking force control device under normal braking conditions according to an exemplary embodiment of this disclosure;

[0052] Figure 9 This is a schematic diagram of the execution logic of an emergency braking condition of a vehicle braking force control device provided in an exemplary embodiment of this disclosure;

[0053] Figure 10 This is a schematic diagram of the execution logic of a vehicle braking force control device under stable critical operating conditions provided by an exemplary embodiment of this disclosure.

[0054] Explanation of icon numbers:

[0055] 100. Braking force control device; 101. Data acquisition module; 102. Working condition identification module; 103. Braking force control module; 200. Hybrid braking system; 201. Front wheel regenerative braking system; 202. Front wheel hydraulic braking system; 203. Rear wheel braking system; 204. Stability function controller. Detailed Implementation

[0056] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0057] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0058] "A and / or B" includes the following three combinations: A only, B only, and a combination of A and B.

[0059] The use of "applies to" or "configured to" in this application implies open and inclusive language, which does not exclude the applicability to or configuration to devices performing additional tasks or steps. Additionally, the use of "based on" implies openness and inclusivity, because processes, steps, calculations, or other actions "based on" one or more of the stated conditions or values ​​may in practice be based on additional conditions or values ​​beyond those stated.

[0060] In this application, the term "exemplary" is used to mean "used as an example, illustration, or description." Any embodiment described as "exemplary" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use this application. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that this application can be made without using these specific details. In other instances, well-known structures and processes are not described in detail to avoid obscuring the description of this application with unnecessary detail. Therefore, this application is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0061] In a first aspect, embodiments of this application provide a braking force control method for a hybrid braking system, such as... Figure 1 As shown, the braking force control method includes the following steps:

[0062] S101. Obtain total braking force request and vehicle status information.

[0063] Total braking force request is a braking demand signal obtained from the intelligent driving system or the driver's application of the brake pedal, used to indicate the total braking force required during the braking process. Vehicle status information is data used to indicate the current vehicle status, such as vehicle speed, yaw rate, acceleration, wheel slip ratio, etc.

[0064] By receiving total braking force requests and vehicle status information, data support is provided for subsequent identification of braking conditions and distribution of braking force.

[0065] S102. Identify the braking condition type based on the total braking force request and vehicle status information.

[0066] Braking conditions include conventional braking, emergency braking, and critical stability conditions. Conventional braking requires less total braking force and prioritizes energy recovery. Emergency braking requires more total braking force and prioritizes reducing braking distance. Critical stability conditions occur when there is a risk of instability and prioritize vehicle stability.

[0067] Braking systems in related technologies, such as Cooperative Regenerative Braking System (CRBS), prioritize the use of electric motors for regenerative braking. Only when the regenerative braking force is insufficient is the hydraulic system used to supplement the required braking force. This approach is difficult to adapt to the different braking requirements of different braking conditions, such as normal braking conditions, emergency braking conditions, and stable critical conditions, resulting in a difficulty in balancing efficiency, safety, and stability.

[0068] In this embodiment, the braking conditions are divided into normal braking conditions, emergency braking conditions, and stable critical conditions based on the total braking force request and vehicle status information, providing a basis for different braking force distributions in subsequent steps for different braking conditions.

[0069] S103. When the braking condition is a conventional braking condition or a stable critical condition, a braking force distribution strategy is executed according to the braking condition type to control the braking force of the hybrid braking system.

[0070] The braking force distribution strategy is a pre-set braking force distribution scheme for normal braking conditions or stable critical conditions. For normal braking conditions, energy recovery is prioritized to reduce hydraulic system losses and improve driving comfort. For stable critical conditions, instability trends are identified in advance to avoid control conflicts and enhance vehicle stability during braking.

[0071] S104. When the braking condition is emergency braking, the braking force of the front wheels and the rear wheels of the vehicle is distributed according to the total braking force request in order to control the braking force of the hybrid braking system.

[0072] In emergency braking situations, the total braking force required is high. If the braking force of the front wheels is saturated, it will not meet the total braking force requirement, affecting the vehicle's braking safety. When the braking force of the front wheels is saturated, the braking force of the rear wheels can be used to supplement the total braking force, thereby shortening the emergency braking distance and ensuring safety.

[0073] This application divides braking conditions into normal braking conditions, emergency braking conditions, and stable critical conditions, and adopts different braking strategies for different braking conditions. In the case of emergency braking, the braking force of the front and rear wheels of the vehicle is distributed according to the total braking force request. If the braking force of the front wheels is insufficient, the braking force of the rear wheels is supplemented to achieve braking force control of the hybrid braking system, meet the braking force requirements, and ensure safety.

[0074] This application provides a braking force control method for a hybrid braking system, wherein the hybrid braking system includes a front wheel regenerative braking system, a front wheel hydraulic braking system, a rear wheel braking system, and a stability function controller.

[0075] Front wheel regenerative braking systems are used to brake a vehicle while recovering energy. For example, a motor energy recovery system (MERS) is a unit that realizes regenerative braking based on a drive motor and its controller. It only acts on the left and right front wheels of the vehicle, converting the vehicle's kinetic energy into electrical energy and recovering it to the power battery during braking, while providing braking force.

[0076] The front wheel hydraulic braking system is used to provide braking force to the front wheels of a vehicle through hydraulic braking. For example, the front hydraulic braking system (FHB) is a traditional hydraulic braking unit that only acts on the left and right front wheels of the vehicle. It consists of components such as a hydraulic pump, brake master cylinder, brake slave cylinder, and brake disc, and provides stable mechanical braking force to the vehicle.

[0077] The rear wheel braking system is used to provide braking force to the rear wheels of a vehicle. For example, the rear wheel one-driving-park system (ODP) is an electronic one-driving-park system driven by a brushless motor. It only acts on the left and right rear wheels of the vehicle, breaking through the static functional limitations of the traditional electronic parking brake (EPB) and expanding into a key supplementary unit for dynamic driving braking. It can provide rear axle deceleration of more than 0.3 times the acceleration due to gravity.

[0078] Stability function controllers are used to ensure vehicle driving stability. For example, they can be integrated with anti-lock braking systems (ABS) or vehicle dynamics controllers (VDC) to monitor vehicle braking stability in real time and prevent wheel lock-up, vehicle fishtailing or skidding by adjusting the braking force of each wheel, thus ensuring vehicle stability.

[0079] like Figure 2 As shown, the braking force control method includes the following steps:

[0080] S201. Obtain total braking force request and vehicle status information.

[0081] Total braking force request is a braking demand signal obtained from the intelligent driving system or the driver pressing the brake pedal, used to indicate the total braking force required for the braking process.

[0082] Vehicle status information is data used to represent the current vehicle status, including inertial measurement data, wheel slip ratio, and vehicle steering status.

[0083] Inertial measurement data is collected by an inertial measurement unit (IMU) and includes yaw rate and lateral acceleration, which are used to reflect the vehicle's attitude stability.

[0084] The wheel slip ratio is calculated from the wheel speed collected by the wheel speed sensor and the current vehicle speed, and is used to determine the tendency of the wheels to lock up.

[0085] Vehicle steering status includes the vehicle's steering angle and steering speed. Combined with yaw rate, the vehicle's steering status can be determined and used to detect the tendency of the vehicle to understeer or oversteer.

[0086] S202. Identify the braking condition type based on the total braking force request and vehicle status information.

[0087] The requested deceleration is obtained based on the total braking force request, and the braking condition type is identified based on the requested deceleration and vehicle status information.

[0088] The total braking force is obtained by parsing the total braking force request. According to the total braking force The requested deceleration was calculated. .

[0089] If the requested deceleration is less than a first deceleration threshold, the braking condition type is determined to be a normal braking condition. In one embodiment, the first deceleration threshold is 0.3 times the gravitational acceleration. ,Right now Under these circumstances, the braking condition type is determined to be conventional braking condition.

[0090] If the requested deceleration exceeds a second deceleration threshold, or if an emergency braking signal is received, the braking condition is determined to be an emergency braking condition. In one embodiment, the second deceleration threshold is 0.9 times the gravitational acceleration. ,Right now In this case, the braking condition type is determined to be an emergency braking condition. In another embodiment, upon receiving an emergency braking signal from a higher-level controller, such as the controller of a vehicle's autonomous driving system, the braking condition type is determined to be an emergency braking condition.

[0091] If instability risk is predicted based on inertial measurement data, the braking condition is determined to be a critical stability condition. Based on inertial measurement data such as yaw rate deviation and lateral acceleration, if vehicle instability risk is predicted—for example, a calculated slip ratio greater than 6% indicates the vehicle is about to fishtail—even if deceleration is requested... If the deceleration is less than the first deceleration threshold, for example, 0.1g to 0.3g, the braking condition is still determined to be a stable critical condition, with stability as the primary objective.

[0092] S203. When the braking condition is a conventional braking condition, a braking force distribution strategy is executed according to the braking condition type to control the braking force of the hybrid braking system.

[0093] like Figure 3 As shown, step S203 includes S2031 to S2033.

[0094] S2031. Obtain the maximum regenerative braking force of the front wheel regenerative braking system.

[0095] Maximum renewable braking force The maximum braking force that the front wheel regenerative braking system can stably output under the current vehicle conditions is dynamically affected by factors such as the external characteristics of the motor, the status of the battery management system, and the current vehicle speed.

[0096] S2032. When the maximum regenerative braking force is greater than or equal to the total braking force request, control the front wheel regenerative braking system to output a braking force equal to the total braking force request in order to brake the front wheels of the vehicle.

[0097] Maximum renewable braking force Greater than or equal to the total braking force request In the case that, This indicates that under the current vehicle conditions, the braking force output by the front wheel regenerative braking system is sufficient to meet the current braking needs, eliminating the need for intervention from other braking systems. This achieves brake energy recovery and increases the vehicle's driving range. Simultaneously, the front wheel hydraulic braking system does not require intervention, resulting in smooth braking force output and improved driving comfort.

[0098] S2033. When the maximum regenerative braking force is less than the total braking force request, the front wheel regenerative braking system is controlled to output braking force at the maximum regenerative braking force, and the front wheel hydraulic braking system outputs braking force equal to the difference between the total braking force request and the maximum regenerative braking force, so as to brake the front wheels of the vehicle.

[0099] Maximum renewable braking force Less than the total braking force request In the case that, This indicates that under the current vehicle condition, the braking force output by the front wheel regenerative braking system is insufficient to meet the current braking demand, requiring intervention from other braking systems to supplement the braking force. The insufficient braking force is determined by the difference between the total requested braking force and the maximum regenerative braking force, and is output by the front wheel hydraulic braking system. Therefore, the braking force output by the front wheel hydraulic braking system is:

[0100] ;

[0101] in The braking force output by the front wheel hydraulic braking system. For total braking force request, The maximum renewable braking force is expressed in N.

[0102] The braking force output by the front wheel hydraulic braking system and the front wheel regenerative braking system meets the total braking force requirement.

[0103] Under normal braking conditions, the braking force output by the front wheel hydraulic braking system and the front wheel regenerative braking system can meet the total braking force requirement, so the intervention of the rear wheel braking system is not required, saving energy and reducing mechanical wear.

[0104] S204. When the braking condition is emergency braking, the braking force of the front wheels and the rear wheels of the vehicle is distributed according to the total braking force request in order to control the braking force of the hybrid braking system.

[0105] like Figure 4 As shown, step S204 includes S2041 to S2043.

[0106] S2041. Obtain the maximum regenerative braking force of the front wheel regenerative braking system and the maximum hydraulic braking force of the front wheel hydraulic braking system.

[0107] Maximum renewable braking force This is the maximum braking force that the front wheel regenerative braking system can stably output under the current vehicle conditions. Maximum hydraulic braking force. This refers to the maximum braking force that the front wheel hydraulic braking system can stably output under the current vehicle conditions.

[0108] S2042. Determine the remaining braking force based on the difference between the total braking force request and the maximum regenerative braking force and the maximum hydraulic braking force.

[0109] Due to the classification of braking conditions, under emergency braking conditions, the total braking force is greater than the sum of the maximum regenerative braking force and the maximum hydraulic braking force. Therefore, the remaining braking force is determined by calculating the difference between the maximum regenerative braking force and the maximum hydraulic braking force. That is, the remaining braking force is... for:

[0110] ;

[0111] in For the remaining braking force, For total braking force, For maximum renewable braking force, The values ​​represent the maximum hydraulic braking force, all in N.

[0112] S2043. The maximum regenerative braking force and the maximum hydraulic braking force are used as the braking force of the front wheels of the vehicle, and the remaining braking force is used as the braking force of the rear wheels of the vehicle. The front wheels are braked by the front wheel regenerative braking system and the front wheel hydraulic braking system based on the braking force of the front wheels of the vehicle, and the rear wheels are braked by the rear wheel braking system based on the braking force of the rear wheels of the vehicle.

[0113] The front wheel regenerative braking system provides maximum regenerative braking force. The front wheel hydraulic braking system applies braking force to the front wheels of the vehicle at maximum hydraulic braking force. Braking force is applied to the front wheels of the vehicle, and the remaining braking force is applied through the rear wheel braking system. It applies braking force to the rear wheels of the vehicle.

[0114] Due to total braking force It is a variable quantity, the maximum regenerative braking force depending on the vehicle's condition. and maximum hydraulic braking force It is also dynamically changing, therefore the remaining braking force is calculated in real time. By precisely delivering braking force to the rear wheels of the vehicle, the braking force generated synchronously by the front and rear wheels of the vehicle can meet the total braking force requirements.

[0115] Compared to traditional electronic parking brakes (EBP), which can only perform static parking and emergency braking with a maximum deceleration of less than or equal to 0.15 times the force of gravity, the rear-wheel driving-parking integrated system (ODP) in this embodiment utilizes the remaining braking force... It generates dynamic clamping force commands, and the left and right domain controllers independently control the output torque of the brushless motor to drive the brake caliper to clamp the rear wheel brake disc, generating controllable power. Its braking force output is not a switch-type operation with only on and off, but a linear adjustment based on the remaining braking force demand. It can dynamically adjust the force according to the working conditions, and has a fast response speed, which can meet the rapid intervention requirements of emergency braking and stability control.

[0116] S205. When the braking condition is a stable critical condition, a braking force distribution strategy is executed according to the braking condition type to control the braking force of the hybrid braking system.

[0117] When the wheel slip ratio tends to exceed the preset slip ratio threshold, or when the vehicle steering state shows a tendency to understeer or oversteer, a coordination signal is sent to the stability function controller so that the stability function controller can take over the control of the power.

[0118] In one embodiment, the slip ratio threshold is 6%. A trend where the wheel slip ratio exceeds the preset slip ratio threshold is characterized by a continuous increase in the slip ratio approaching 6%, indicating that the wheels are about to lock up. Understeer trend is when the actual steering angle of the vehicle is less than the expected steering angle and cannot reach the expected steering angle, while oversteer trend is when the actual steering angle of the vehicle is greater than the expected steering angle and cannot reach the expected steering angle.

[0119] In traditional Cooperative Regenerative Braking Systems (CRBS), when the stability function controller is triggered during braking, the system typically only passively disengages regenerative braking, handing over full control to the stability function controller. This response is passive and delayed, lacking a mechanism to predictively adjust braking force distribution based on vehicle conditions before the stability function controller is triggered, in order to prevent instability.

[0120] In this embodiment, when the wheel slip ratio tends to exceed the preset slip ratio threshold, or when the vehicle steering state shows a tendency towards understeer or oversteer, the wheel slip ratio trend is monitored in advance. Before the stability function controller is passively triggered, the braking force of the vehicle's rear wheels is reduced to prevent wheel lock-up. At the same time, the stability function controller is actively coordinated, and the current braking force status of the vehicle's rear wheels is informed to the stability function controller. The stability function controller then takes over the control of the braking force to ensure the stability of the vehicle.

[0121] S206. When the stability function controller is triggered by either the normal braking condition or the emergency braking condition, a coordination signal is sent to the stability function controller so that the stability function controller can take over the control of the power.

[0122] Reduce the braking force output of the front wheel regenerative braking system and disengage the front wheel regenerative braking system; adjust the braking force output of the front wheel hydraulic braking system and the rear wheel braking system according to the control command of the stability function controller.

[0123] Under normal braking conditions and emergency braking conditions, when the stability function controller is detected to be triggered, a coordination signal is sent to the stability function controller so that the stability function controller can take over the control of the braking force without waiting for command feedback, ensuring that the stability function controller can smoothly take over the control of the braking force.

[0124] While coordinating signal transmission, the front wheel regenerative braking system is disengaged, and the regenerative torque of the drive motor is quickly adjusted through the motor controller. For example, within 200ms, the deceleration corresponding to the regenerative braking force is reduced to below 0.1 times the gravitational acceleration until the front wheel regenerative braking system stops outputting braking force, thus avoiding additional impact of regenerative braking force on wheel slip ratio.

[0125] While ensuring stability, the ratio of regenerative braking to hydraulic braking on the front axle should be adjusted appropriately to avoid sudden changes in braking force.

[0126] Secondly, embodiments of this application also provide a braking force control device for a hybrid braking system, such as... Figure 5 As shown, the braking force control device 100 includes a data acquisition module 101, a working condition identification module 102, and a braking force control module 103.

[0127] The data acquisition module 101 is used to acquire total braking force requests and vehicle status information. By receiving total braking force requests and vehicle status information, it provides data support for subsequent identification of braking condition types and braking force distribution.

[0128] The operating condition identification module 102 is used to identify the braking condition type based on the total braking force request and vehicle status information. The braking condition types include normal braking condition, emergency braking condition, and stable critical condition. Classifying the braking condition type into normal braking condition, emergency braking condition, and stable critical condition based on the total braking force request and vehicle status information provides a basis for adopting different braking force distributions for different braking conditions in subsequent steps.

[0129] The braking force control module 103 is used to control the braking force by executing a braking force distribution strategy according to the braking condition type, whether it is a normal braking condition or an emergency braking condition. In the case of emergency braking, it distributes the braking force between the front and rear wheels of the vehicle according to the total braking force request. The braking force distribution strategy is a preset braking force distribution scheme for normal braking conditions or stable critical conditions. For normal braking conditions, energy recovery is prioritized to reduce hydraulic system losses and improve driving comfort. For stable critical conditions, instability trends are identified in advance to avoid control conflicts and enhance vehicle stability during braking. In emergency braking conditions, the total braking force demand is high. If the braking force of the front wheels is saturated, it will not meet the total braking force demand, affecting vehicle braking safety. When the braking force of the front wheels is saturated, it is supplemented by the braking force of the rear wheels to meet the total braking force demand, shorten the emergency braking distance, and ensure safety.

[0130] Thirdly, embodiments of this application also provide a vehicle, such as Figure 6 As shown, it includes a hybrid braking system 200 and a braking force control device 100.

[0131] The hybrid braking system 200 includes a front wheel regenerative braking system 201, a front wheel hydraulic braking system 202, a rear wheel braking system 203, and a stability function controller 204. The braking force control device 100 of the hybrid braking system 200 is connected to the hybrid braking system 200.

[0132] like Figure 7 The braking force control device 100 is used to acquire total braking force requests and vehicle status information, such as analyzing driver intentions based on pedal travel signals, calculating reference vehicle speed and wheel acceleration based on wheel speed signals to calculate slip ratio, and arbitrating stability functions based on gear signals and motor torque signals.

[0133] The braking condition type is identified based on the total braking force request and vehicle status information, and a braking force distribution strategy is executed according to the braking condition type to control the braking force of the hybrid braking system 200.

[0134] like Figure 8As shown, under normal braking conditions, the front wheel regenerative braking system 201 outputs sufficient maximum regenerative braking force to apply braking force to the front wheels of the vehicle. When the braking force of the front wheel regenerative braking system 201 is insufficient, the front wheel hydraulic braking system 202 outputs the insufficient braking force.

[0135] like Figure 9 As shown, under emergency braking conditions, the maximum regenerative braking force is output through the front wheel regenerative braking system 201, the maximum hydraulic braking force is output through the front wheel hydraulic braking system 202, the remaining braking force is calculated, and the remaining braking force is output to the rear wheels of the vehicle through the rear wheel braking system 203.

[0136] like Figure 10 Under stable critical operating conditions, when the wheel slip ratio tends to exceed a preset slip ratio threshold, or when the vehicle's steering state shows a tendency towards understeer or oversteer, the braking force of the front wheel regenerative braking system 201 and the braking force of the rear wheel braking system 203 are adjusted. A coordination signal is then sent to the stability function controller 204 to enable the stability function controller 204 to control the braking force.

[0137] This application divides braking conditions into normal braking conditions, emergency braking conditions, and stable critical conditions, and adopts different braking strategies for different braking conditions. In the case of emergency braking, the braking force of the front and rear wheels of the vehicle is distributed according to the total braking force request. If the braking force of the front wheels is insufficient, the braking force of the rear wheels is supplemented to achieve braking force control of the hybrid braking system, meet the braking force requirements, and ensure safety.

[0138] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0139] The above provides a detailed description of the braking force control method, device, and vehicle of a hybrid braking system provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A braking force control method for a hybrid braking system, characterized in that, The hybrid braking system includes a front wheel regenerative braking system, a front wheel hydraulic braking system, and a rear wheel braking system, wherein the rear wheel braking system is a rear wheel driving and parking integrated system; the braking force control method includes the following steps: Obtain total braking force request and vehicle status information; The braking condition type is identified based on the total braking force request and the vehicle status information. The braking condition type includes normal braking condition, emergency braking condition and stable critical condition. When the braking condition type is the conventional braking condition or the stable critical condition, a braking force distribution strategy is executed according to the braking condition type to control the braking force of the hybrid braking system. When the braking condition type is the emergency braking condition, the maximum regenerative braking force of the front wheel regenerative braking system and the maximum hydraulic braking force of the front wheel hydraulic braking system are obtained; the remaining braking force is determined based on the difference between the total braking force request and the maximum regenerative braking force and the maximum hydraulic braking force; the maximum regenerative braking force and the maximum hydraulic braking force are used as the braking force of the front wheels of the vehicle, and the remaining braking force is used as the braking force of the rear wheels of the vehicle, so that the front wheels of the vehicle are braked by the front wheel regenerative braking system and the front wheel hydraulic braking system based on the braking force of the front wheels of the vehicle, and the rear wheels of the vehicle are braked by the rear wheel braking system based on the braking force of the rear wheels of the vehicle.

2. The braking force control method for the hybrid braking system according to claim 1, characterized in that, Identifying the braking condition type based on the total braking force request and the vehicle status information includes: The requested deceleration is obtained based on the total braking force request; The braking condition type is identified based on the requested deceleration and the vehicle status information.

3. The braking force control method for the hybrid braking system according to claim 2, characterized in that, The vehicle status information includes inertial measurement data; The step of identifying the braking condition type based on the requested deceleration and the vehicle status information includes: If the requested deceleration is less than the first deceleration threshold, the braking condition type is determined to be the normal braking condition. If the requested deceleration is greater than the second deceleration threshold, or if an emergency braking signal is received, the braking condition type is determined to be the emergency braking condition. If an instability risk is predicted based on the inertial measurement data, the braking condition type is determined to be the critical stability condition.

4. The braking force control method for the hybrid braking system according to claim 1, characterized in that, When the braking condition type is normal braking condition, a braking force distribution strategy is executed according to the braking condition type, including: Obtain the maximum regenerative braking force of the front wheel regenerative braking system; When the maximum regenerative braking force is greater than or equal to the total braking force request, the front wheel regenerative braking system is controlled to output a braking force equal to the total braking force request in order to brake the front wheels of the vehicle. When the maximum regenerative braking force is less than the total braking force request, the front wheel regenerative braking system is controlled to output braking force at the maximum regenerative braking force, and the front wheel hydraulic braking system outputs braking force equal to the difference between the total braking force request and the maximum regenerative braking force, so as to brake the front wheels of the vehicle.

5. The braking force control method for the hybrid braking system according to claim 1, characterized in that, The hybrid braking system also includes a stability function controller; the vehicle status information also includes wheel slip ratio and vehicle steering status; When the braking condition type is the stable critical condition, a braking force distribution strategy is executed according to the braking condition type, including: If the wheel slip ratio tends to exceed a preset slip ratio threshold, or if the vehicle steering state shows a tendency to understeer or oversteer, a coordination signal is sent to the stability function controller so that the stability function controller takes over the control of the braking force.

6. The braking force control method for the hybrid braking system according to claim 5, characterized in that, The control method further includes: When the stability function controller is triggered by either the normal braking condition or the emergency braking condition, a coordination signal is sent to the stability function controller so that the stability function controller takes over the control of the braking force.

7. The braking force control method for a hybrid braking system according to claim 6, characterized in that, After the stability function controller takes over the control of the braking force, the braking force control method further includes: Reduce the braking force output by the front wheel regenerative braking system and disengage the front wheel regenerative braking system; The braking force output by the front wheel hydraulic braking system and the rear wheel braking system is adjusted according to the control command of the stability function controller.

8. A braking force control device for a hybrid braking system, characterized in that, The hybrid braking system includes a front wheel regenerative braking system, a front wheel hydraulic braking system, and a rear wheel braking system, wherein the rear wheel braking system is a rear wheel driving and parking integrated system. The braking force control device includes: The data acquisition module is used to acquire total braking force requests and vehicle status information; The operating condition identification module is used to identify the braking condition type based on the total braking force request and the vehicle status information. The braking condition type includes normal braking condition, emergency braking condition and stable critical condition. The braking force control module is used to control the braking force by executing a braking force distribution strategy according to the braking condition type when the braking condition type is a normal braking condition or a stable critical condition; when the braking condition type is an emergency braking condition, it acquires the maximum regenerative braking force of the front wheel regenerative braking system and the maximum hydraulic braking force of the front wheel hydraulic braking system; determines the remaining braking force based on the difference between the total braking force request and the maximum regenerative braking force and the maximum hydraulic braking force; uses the maximum regenerative braking force and the maximum hydraulic braking force as the braking force of the front wheels of the vehicle, and uses the remaining braking force as the braking force of the rear wheels of the vehicle, so that the front wheels of the vehicle are braked by the front wheel regenerative braking system and the front wheel hydraulic braking system according to the braking force of the front wheels of the vehicle, and the rear wheels of the vehicle are braked by the rear wheel braking system according to the braking force of the rear wheels of the vehicle.

9. A vehicle, characterized in that, include: A hybrid braking system, comprising a front wheel regenerative braking system, a front wheel hydraulic braking system, a rear wheel braking system, and a stability function controller; The braking force control device of the hybrid braking system as described in claim 8, wherein the braking force control device of the hybrid braking system is connected to the hybrid braking system.

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