Vehicle braking control method and device, electronic equipment and storage medium

Abstract

This application discloses a vehicle braking control method, device, electronic equipment, and storage medium, comprising: monitoring the coefficient of friction of the road surface on which the vehicle is located, identifying whether the vehicle is in a split-road braking condition, obtaining the yaw angle deviation of the vehicle, determining the first longitudinal braking force of the first front wheel based on the yaw angle deviation, determining the second longitudinal braking force and rear wheel steering angle of the first rear wheel based on a predetermined target braking state of the vehicle, determining the braking clamping force of the second pair of wheels based on an anti-lock braking system (ABS) strategy, and, when the vehicle is in a split-road braking condition, performing braking control on the corresponding wheels based on the first longitudinal braking force, rear wheel steering angle, second longitudinal braking force, and braking clamping force. This application, through independent and precise management of each wheel, enables coordinated operation of the front wheel yaw control on the high-friction side, the rear wheel feedforward steering and braking, and the ABS control of the two wheels on the low-friction side, thereby improving the vehicle's split-road braking performance.

Description

Technical Field

[0001] This application belongs to the field of vehicle control technology, specifically relating to a vehicle braking control method, device, electronic equipment, and storage medium. Background Technology

[0002] With the rapid development of the automotive industry and the increasing complexity of road traffic environments, the braking safety of vehicles under various road conditions has become a research focus. In particular, when performing emergency braking on split-surface roads, the adhesion coefficients of the two sides of the road are significantly different. For example, if one side is a dry asphalt road and the other side is a wet or icy road, the vehicle is prone to yaw moment due to the asymmetry of braking forces on both sides, causing the vehicle to yaw and seriously threatening driving safety.

[0003] Currently, the mainstream approach in the industry for split-road surfaces is to use a combined hydraulic braking and front-wheel steering control method. Specifically, the hydraulic braking system is responsible for adjusting the braking force of all four wheels, while the front-wheel steering system generates additional yaw moment to balance the yaw moment caused by the asymmetry of braking force. However, due to the inherent hydraulic coupling problem in the structure of the hydraulic braking system, the braking force of the four wheels cannot be adjusted quickly and accurately. When facing split-road surfaces that require rapid response and precise control, the adjustment speed and accuracy of the hydraulic braking system cannot meet the requirements, resulting in uneven distribution of braking force. In practical applications, the front-wheel steering system is subject to driver intervention and cannot achieve fully active control. Furthermore, the driver's reaction time and operational precision are limited in emergency situations, making it difficult to seamlessly coordinate with the control of the braking system, thus limiting the control effect. In summary, the current combined hydraulic braking and front-wheel steering control method results in uneven distribution of braking force, and the front-wheel steering is difficult to coordinate with the control of the braking system, leading to limited optimization of braking performance on split-road surfaces. This makes it difficult to meet the safety and braking efficiency requirements on split-road surfaces, thus affecting the braking performance of vehicles on split-road surfaces. Summary of the Invention

[0004] The purpose of this application is to provide a vehicle braking control method, device, electronic device, and storage medium that can solve the problems of uneven braking force distribution and difficulty in coordinating front wheel steering with the braking system control in current hydraulic braking and front wheel steering control, resulting in limited optimization of braking performance on split-road surfaces and difficulty in meeting the safety and braking efficiency requirements on split-road surfaces, thereby affecting the vehicle's braking performance on split-road surfaces.

[0005] To solve the above-mentioned technical problems, this application is implemented as follows: In a first aspect, embodiments of this application provide a vehicle braking control method, the method comprising: Monitor the coefficient of friction of the road surface where the vehicle is located to identify whether the vehicle is in a split-road braking condition; wherein, the split-road braking condition is when the left and right sides of the wheel are on the first side road surface and the second side road surface, and the coefficient of friction of the first side road surface is higher than the coefficient of friction of the second side road surface. Obtain the yaw angle deviation of the vehicle, and determine the first longitudinal braking force of the first front wheel based on the yaw angle deviation; Based on the predetermined target braking state of the vehicle, the second longitudinal braking force and the rear wheel steering angle of the first side rear wheel are determined; wherein, the target braking state is obtained by steady-state analysis with the goal of keeping the vehicle moving straight and the braking deceleration reaching a threshold, satisfying the constraints of the vehicle dynamics model and the tire force model; Based on the anti-lock braking system (ABS) strategy, determine the braking clamping force of the second-side dual wheels; When the vehicle is in the braking condition of the split road surface, braking control is performed on the corresponding wheels according to the first longitudinal braking force, the rear wheel steering angle, the second longitudinal braking force, and the braking clamping force.

[0006] Optionally, obtaining the yaw angle deviation of the vehicle and determining the first longitudinal braking force of the first front wheel based on the yaw angle deviation includes: Obtain the actual yaw rate of the vehicle, and use the difference between the actual yaw rate and the preset expected yaw rate as the yaw angle deviation; Obtain the sliding surface corresponding to the yaw angle deviation; The first longitudinal braking force of the first front wheel is determined based on the yaw angle deviation and the sliding surface corresponding to the yaw angle deviation.

[0007] Optionally, determining the second longitudinal braking force and rear wheel steering angle of the first rear wheel based on a predetermined target braking state of the vehicle includes: The target braking state of the vehicle is determined by steady-state analysis; the target braking state includes the longitudinal tire force of each wheel and the rear wheel steering angle when the vehicle is traveling straight on a split road surface and the braking deceleration reaches a threshold. The longitudinal tire force of the first side rear wheel determined by the steady-state analysis is used as the second longitudinal braking force, and the rear wheel steering angle determined by the steady-state analysis is used as the rear wheel steering angle of the first side rear wheel.

[0008] Optionally, determining the target braking state of the vehicle through steady-state analysis includes: Based on the vehicle's longitudinal resultant force, lateral resultant force, and yaw moment, a vehicle dynamics model incorporating rear-wheel steering is created. A tire force model is created based on preset constraints; the constraints include zero yaw rate, zero lateral acceleration in the road coordinate system, and setting the tire longitudinal force and tire lateral force to satisfy the friction circle constraint. With the goal of keeping the vehicle moving straight and the braking deceleration reaching a threshold, satisfying the constraints of the vehicle dynamics model and tire force model, steady-state analysis is used to determine the target braking state of the vehicle.

[0009] Optionally, setting the tire longitudinal force and tire lateral force to satisfy the friction circle constraint includes: The friction circle limit of the wheel is determined based on the adhesion coefficient of the first side road surface, the adhesion coefficient of the second side road surface, and the vertical load on the wheel. The safety boundary of the friction circle limit is determined based on a preset safety factor; The longitudinal and lateral forces of the tires are set at safe boundaries defined by the friction circle.

[0010] Optionally, determining the braking clamping force of the second-side dual wheels according to the anti-lock braking control strategy includes: Obtain dynamic feedforward compensation determined by the adhesion coefficient of the second side road surface and the longitudinal acceleration of the vehicle; Obtain the actual braking clamping force of the second-side dual wheels; The braking clamping force of the second-side dual wheels is determined based on the dynamic feedforward compensation and the actual braking clamping force.

[0011] Optionally, the step of controlling the braking of the corresponding wheel based on the first longitudinal braking force, the rear wheel steering angle, the second longitudinal braking force, and the braking clamping force includes: The first longitudinal braking force is applied to the first front wheel on the first side for closed-loop control. The second longitudinal braking force is applied to the first side rear wheel, and the actual rear wheel steering angle of the first side rear wheel is logically gradually controlled so that the actual rear wheel steering angle smoothly approaches the rear wheel steering angle. Control the second-side dual wheels to perform anti-lock braking according to the braking clamping force.

[0012] Secondly, embodiments of this application provide a vehicle braking control device, the device comprising: The identification module is used to monitor the adhesion coefficient of the road surface where the vehicle is located and to identify whether the vehicle is in a split-road braking condition; wherein, the split-road braking condition is that the left and right sides of the wheels are on the first side road surface and the second side road surface, and the adhesion coefficient of the first side road surface is higher than the adhesion coefficient of the second side road surface. The first determining module is used to obtain the yaw angle deviation of the vehicle and determine the first longitudinal braking force of the first front wheel based on the yaw angle deviation. The second determining module is used to determine the second longitudinal braking force and the rear wheel steering angle of the first side rear wheel based on the predetermined target braking state of the vehicle; wherein, the target braking state is obtained by steady-state analysis with the goal of keeping the vehicle moving straight and the braking deceleration reaching a threshold, satisfying the constraints of the vehicle dynamics model and the tire force model; The third determining module is used to determine the braking clamping force of the second-side dual wheels based on the anti-lock braking control strategy; The control module is used to control the braking of the corresponding wheels based on the first longitudinal braking force, the rear wheel steering angle, the second longitudinal braking force, and the braking clamping force when the vehicle is in the braking condition of the split road surface.

[0013] Thirdly, embodiments of this application provide an electronic device including a processor, a memory, and a program or instructions stored in the memory and executable on the processor, wherein the program or instructions, when executed by the processor, implement the steps of the vehicle braking control method as described in the first aspect.

[0014] Fourthly, embodiments of this application provide a readable storage medium storing a program or instructions that, when executed by a processor, implement the steps of the vehicle braking control method as described in the first aspect.

[0015] The vehicle braking control method provided in this application identifies whether the vehicle is in a split-road braking condition by monitoring the adhesion coefficient of the road surface on which the vehicle is located. In the split-road braking condition, the left and right sides of the wheels are on a first side road and a second side road, with the adhesion coefficient of the first side road being higher than that of the second side road. The yaw angle deviation of the vehicle is obtained, and based on the yaw angle deviation, the first longitudinal braking force of the first front wheel is determined. Based on a predetermined target braking state of the vehicle, the second longitudinal braking force and the rear wheel steering angle are determined. The target braking state is obtained through steady-state analysis with the goal of maintaining straight-line travel and achieving a braking deceleration threshold that satisfies the constraints of the vehicle dynamics model and tire force model. Based on the anti-lock braking strategy, the braking clamping force of the second dual wheels is determined. When the vehicle is in a split-road braking condition, braking control is applied to the corresponding wheels based on the first longitudinal braking force, the rear wheel steering angle, the second longitudinal braking force, and the braking clamping force. In this embodiment, when the vehicle is identified to be in a complex split-road condition, closed-loop and feedforward control are used for the front and rear wheels on the high-adhesion side, respectively, while the dual wheels on the low-adhesion side are focused on anti-lock braking control. By managing each wheel independently and precisely, the yaw control of the front wheels on the high-adhesion side, the feedforward steering and braking of the rear wheels, and the ABS control of the dual wheels on the low-adhesion side work together to effectively prevent yaw while significantly shortening the braking distance. This greatly improves the braking performance optimization on split-road surfaces, meets the safety and braking efficiency requirements on split-road surfaces, and further enhances the vehicle's braking performance on split-road surfaces.

[0016] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below. Attached Figure Description

[0017] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a flowchart illustrating the steps of a vehicle braking control method provided in an embodiment of this application; Figure 2 This is a schematic diagram of the architecture of a vehicle braking control method provided in an embodiment of this application; Figure 3 This is a schematic diagram of a vehicle dynamics model in a vehicle braking control method provided in an embodiment of this application; Figure 4This is a schematic diagram of a vehicle braking control method provided in an embodiment of this application; Figure 5 This is a schematic flowchart of a vehicle braking control method provided in an embodiment of this application; Figure 6 This is a schematic diagram of the structure of a vehicle braking control device provided in an embodiment of this application; Figure 7 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0018] 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, 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.

[0019] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0020] The vehicle braking control method, device, electronic equipment, and storage medium provided in this application will be described in detail below with reference to the accompanying drawings and through specific embodiments and application scenarios.

[0021] Reference Figure 1 The diagram illustrates a flowchart of a vehicle braking control method according to an embodiment of this application. The method may include: Step 101: Monitor the coefficient of adhesion of the road surface where the vehicle is located to identify whether the vehicle is in a braking condition on a split road surface.

[0022] Among them, the braking condition of the split road surface is that the left and right sides of the wheel are on the first side road surface and the second side road surface, and the adhesion coefficient of the first side road surface is higher than that of the second side road surface.

[0023] In this embodiment, to address the current issue of uneven braking force distribution and difficulty in coordinating front wheel steering with the braking system control in hydraulic braking and front wheel steering coordination, resulting in limited braking performance optimization on split-road surfaces and failing to meet the safety and braking efficiency requirements on split-road surfaces, thus affecting the vehicle's braking performance on split-road surfaces, the following solution is proposed: Figure 4This illustration shows a schematic diagram of a vehicle braking control method provided in an embodiment of this application. Specifically, a differentiated wheel control architecture is proposed. Based on the adhesion differences of the split road surface, the vehicle wheels are divided into three control zones, and targeted braking control is applied. The low-adhesion side wheels employ an Anti-lock Braking System (ABS) control strategy to ensure that these wheels do not lock up and maintain basic stability. The high-adhesion side front wheels implement closed-loop control with yaw rate as the feedback target, actively generating compensating yaw moment by dynamically adjusting their braking force to suppress vehicle yaw. The high-adhesion side rear wheels employ feedforward control based on vehicle steady-state analysis, applying a determined braking force and rear wheel steering angle. This assists in stabilizing the vehicle body and maximizes the use of the high-adhesion road surface to provide braking force. The three controls for the low-adhesion side, the high-adhesion side front wheels, and the high-adhesion side rear wheels are combined into a unified cooperative braking control. This is integrated through vehicle dynamics models and steady-state analysis, achieving simultaneous optimization of vehicle directional stability and longitudinal braking efficiency on complex split road surfaces.

[0024] In this embodiment, the split-road braking condition is that the left and right sides of the wheel are on the first side road and the second side road, and the adhesion coefficient of the first side road is higher than that of the second side road. It should be noted that the split-road braking condition can be that the left wheel of the vehicle is on the first side road and the right wheel is on the second side road, that is, the adhesion coefficient of the left wheel on the first side road is higher than that of the right wheel on the second side road. Alternatively, it can be that the right wheel of the vehicle is on the first side road and the left wheel is on the second side road, that is, the adhesion coefficient of the right wheel on the first side road is higher than that of the left wheel on the second side road.

[0025] The coefficient of friction (COP) is an indicator of the frictional capacity between the tire and the road surface, reflecting the vehicle's grip and driving safety under different road conditions. The COP is the ratio of tire adhesion to wheel normal pressure, and can be roughly considered as the static friction coefficient between the tire and the road surface. A higher COP means greater available adhesion for the vehicle, making it less prone to slippage. Split-road surfaces refer to the road surfaces in contact with the left and right wheels of a vehicle, where their physical properties, especially the COP, are completely different. For example, the left wheel might be on a dry asphalt road while the right wheel is on an icy surface, or the left wheel might be on a sandy shoulder while the right wheel is on a paved asphalt road, and so on.

[0026] In this embodiment, the vehicle can monitor the coefficient of friction of the road surface it is on using sensors or machine learning algorithms. Based on the coefficient of friction, it can identify whether the vehicle is in a split-road braking condition. If the left and right wheels are on the first and second sides of the road surface, and the coefficient of friction of the first side is higher than that of the second side, then the vehicle is in a split-road braking condition. In this condition, the braking force of the two wheels is inconsistent, which severely affects the vehicle's braking performance and can easily lead to loss of control or yaw. Otherwise, the vehicle is not in a split-road braking condition. Identifying whether the vehicle is in a split-road braking condition helps the vehicle adjust its braking control strategy in a timely manner, avoiding loss of control or skidding and ensuring driving safety.

[0027] Sensor monitoring can employ various sensors, including wheel speed sensors, longitudinal acceleration sensors, lateral acceleration sensors, and brake pressure sensors. Wheel speed sensors monitor changes in wheel speed to determine the road surface adhesion coefficient. When a vehicle brakes on a low-adhesion surface, the wheels are prone to slippage, and the wheel speed drops sharply. Longitudinal acceleration sensors measure the vehicle's longitudinal acceleration to obtain the vehicle's dynamic state during braking or acceleration, thus determining the road surface adhesion coefficient. Lateral acceleration sensors measure the vehicle's lateral acceleration to help assess the vehicle's stability during curves or lane changes, reflecting the adhesion coefficient. Brake pressure sensors monitor the hydraulic or pneumatic pressure of the braking system to determine the magnitude of the braking force, thereby obtaining the adhesion coefficient. In addition, some vehicle systems can use machine learning algorithms to train models using historical and real-time sensor data to predict the road surface adhesion coefficient; these will not be elaborated upon here.

[0028] Step 102: Obtain the yaw angle deviation of the vehicle, and determine the first longitudinal braking force of the first front wheel based on the yaw angle deviation.

[0029] In this embodiment, the vehicle's yaw angle is a crucial dynamic parameter during braking or steering. The yaw angle refers to the rotational angle of the vehicle around its vertical axis, closely related to its steering sensitivity and dynamic characteristics, affecting its stability and handling during cornering. The yaw angle can be determined by the vehicle's speed and turning radius, and its yaw rate can be estimated using wheel speed differences. Yaw angle deviation refers to the difference between the vehicle's actual yaw angle and the desired yaw angle. When a vehicle is traveling on complex road conditions, such as braking on a split-plane surface, yaw angle deviation can lead to loss of control or skidding. Therefore, by adjusting the vehicle's braking force distribution, particularly the longitudinal braking force of the first front wheel, the yaw angle deviation can be effectively controlled, thereby improving vehicle stability and safety.

[0030] Step 103: Determine the second longitudinal braking force and rear wheel steering angle of the first side rear wheel based on the predetermined target braking state of the vehicle.

[0031] The target braking state is obtained through steady-state analysis with the goal of keeping the vehicle moving straight and the braking deceleration reaching a threshold, satisfying the constraints of the vehicle dynamics model and the tire force model.

[0032] In this embodiment of the application, under the condition of braking on a split road surface, the road surface adhesion coefficients of the wheels on both sides of the vehicle are different, which may cause the vehicle to yaw, skid, or become unstable during braking. In order to ensure that the vehicle can maintain straight travel and the braking deceleration reaches a predetermined threshold under the split road surface, it is necessary to determine the target braking state of the vehicle through steady-state analysis and adjust the longitudinal braking force of the first rear wheel and the rear wheel steering angle accordingly.

[0033] In this embodiment, steady-state analysis refers to assuming the vehicle is in a stable state, such as zero yaw rate and zero lateral acceleration, in the vehicle dynamics model. By analyzing parameters such as the longitudinal resultant force, lateral resultant force, and yaw moment, the ideal state of the vehicle under specific working conditions is determined. Using steady-state analysis, a nonlinear programming solver is used to determine the upper limit of braking of the vehicle under different split-road surfaces, as well as the corresponding four-wheel braking force and rear wheel steering angle. Thus, based on the predetermined target braking state of the vehicle, the second longitudinal braking force and rear wheel steering angle of the first rear wheel are determined. The target braking state is obtained by steady-state analysis with the goal of keeping the vehicle moving straight and the braking deceleration reaching a threshold, satisfying the constraints of the vehicle dynamics model and the tire force model. The target braking state includes the longitudinal tire force and rear wheel steering angle of each wheel when the vehicle is moving straight under split-road surfaces and the braking deceleration reaches the threshold.

[0034] In this embodiment, the vehicle dynamics model is a mathematical model describing the vehicle's motion state under different operating conditions. This model typically includes longitudinal motion equations, lateral motion equations, and yaw motion equations. Based on preset constraints, a tire force model is created. The steady-state constraints include a zero yaw rate, zero lateral acceleration in the road coordinate system, and the setting that the tire longitudinal and lateral forces satisfy the friction circle constraint. Therefore, with the goal of maintaining straight-line travel and achieving a braking deceleration threshold while satisfying the constraints of the vehicle dynamics model and the tire force model, steady-state analysis determines the vehicle's target braking state. The longitudinal tire force of the first rear wheel determined in the steady-state analysis is the second longitudinal braking force, calculated based on the target braking state. This force is used to ensure the vehicle maintains straight-line travel and achieves a braking deceleration threshold on a split-road surface. The rear wheel steering angle determined in the steady-state analysis is used to adjust the vehicle's yaw dynamics to ensure the vehicle maintains straight-line travel on a split-road surface. The magnitude and direction of the rear wheel steering angle are determined based on the target braking state.

[0035] Step 104: Determine the braking clamping force of the second-side dual wheels according to the anti-lock braking control strategy.

[0036] In this embodiment of the application, under the condition of braking on a split road surface, the second wheel of the vehicle, i.e. the side with a lower coefficient of adhesion, is prone to lock-up, which can lead to loss of vehicle control or skidding. In order to prevent the second wheel from locking up, it is necessary to dynamically adjust the braking clamping force of the two wheels on the second side through an anti-lock braking control strategy to ensure that the vehicle maintains stability and controllability during braking. Therefore, according to the anti-lock braking control strategy, the braking clamping force of the two wheels on the second side is determined. The braking clamping force refers to the force applied to the brake pads during emergency braking, which is the force that presses the brake pads onto the brake disc to ensure that the vehicle can effectively decelerate or stop during braking.

[0037] In this embodiment, the anti-lock braking control strategy includes wheel slippage detection, brake pressure adjustment, and dynamic feedforward compensation. Wheel slippage is detected by a wheel speed sensor. If the wheel slippage rate exceeds a preset threshold, the wheel is considered about to lock up. Based on the wheel slippage, the brake pressure is adjusted: if the wheel is about to lock up, the brake pressure is reduced; if the wheel slippage rate is low, the brake pressure is increased. During braking, the brake clamping force is dynamically adjusted based on the coefficient of adhesion and longitudinal acceleration to prevent wheel lockup. Details are omitted here.

[0038] Step 105: When the vehicle is in a braking condition on a split road surface, brake control is applied to the corresponding wheels based on the first longitudinal braking force, the rear wheel steering angle, the second longitudinal braking force, and the brake clamping force.

[0039] In this embodiment, by independently and precisely managing each wheel, closed-loop and feedforward control are applied to the front and rear wheels on the high-adhesion side, respectively, allowing the two wheels on the low-adhesion side to focus on anti-lock braking. This enables the front wheel yaw control, rear wheel feedforward steering and braking, and ABS control on the low-adhesion side to work together to form a highly efficient collaborative mechanism. Specifically, when the vehicle is braking on a split-road surface, braking control is applied to the corresponding wheels based on the first longitudinal braking force, the rear wheel steering angle, the second longitudinal braking force, and the braking clamping force.

[0040] In this embodiment, the first longitudinal braking force is calculated based on the yaw angle deviation and is used to adjust the vehicle's yaw dynamics to avoid oversteer or understeer. Closed-loop control is achieved by applying the first longitudinal braking force to the first front wheel. The second longitudinal braking force is calculated based on the target braking state determined by steady-state analysis and is used to ensure that the vehicle maintains straight-line travel on the split-road surface and that the braking deceleration reaches a threshold. The rear wheel steering angle is calculated based on the target braking state determined by steady-state analysis and is used to adjust the vehicle's yaw dynamics to ensure that the vehicle maintains straight-line travel on the split-road surface. Based on the second longitudinal braking force and the rear wheel steering angle of the first rear wheel, the braking and steering dynamics of the first rear wheel are adjusted in advance to ensure that the vehicle maintains straight-line travel on the split-road surface. To prevent the second pair of wheels from locking up during braking, the braking clamping force is dynamically adjusted to achieve anti-lock braking, ensuring that the vehicle maintains stability and controllability during braking. This effectively prevents yaw while significantly shortening the braking distance.

[0041] The vehicle braking control method provided in this application identifies whether the vehicle is in a split-road braking condition by monitoring the adhesion coefficient of the road surface on which the vehicle is located. In the split-road braking condition, the left and right sides of the wheels are on a first side road and a second side road, with the adhesion coefficient of the first side road being higher than that of the second side road. The yaw angle deviation of the vehicle is obtained, and based on the yaw angle deviation, the first longitudinal braking force of the first front wheel is determined. Based on a predetermined target braking state of the vehicle, the second longitudinal braking force and the rear wheel steering angle are determined. The target braking state is obtained through steady-state analysis with the goal of maintaining straight-line travel and achieving a braking deceleration threshold that satisfies the constraints of the vehicle dynamics model and tire force model. Based on the anti-lock braking strategy, the braking clamping force of the second dual wheels is determined. When the vehicle is in a split-road braking condition, braking control is applied to the corresponding wheels based on the first longitudinal braking force, the rear wheel steering angle, the second longitudinal braking force, and the braking clamping force. In this embodiment, when the vehicle is identified to be in a complex split-road condition, closed-loop and feedforward control are used for the front and rear wheels on the high-adhesion side, respectively, while the dual wheels on the low-adhesion side are focused on anti-lock braking control. By managing each wheel independently and precisely, the yaw control of the front wheels on the high-adhesion side, the feedforward steering and braking of the rear wheels, and the ABS control of the dual wheels on the low-adhesion side work together to effectively prevent yaw while significantly shortening the braking distance. This greatly improves the braking performance optimization on split-road surfaces, meets the safety and braking efficiency requirements on split-road surfaces, and further enhances the vehicle's braking performance on split-road surfaces.

[0042] For ease of understanding by those skilled in the art, refer to Figure 2This diagram illustrates the architecture of a vehicle braking control method provided in this application. Taking a vehicle model with its left wheel on a high-friction surface and its right wheel on a low-friction surface as an example, the method collects road information and obtains the adhesion coefficient on the high-friction side. and low adhesion coefficient It identifies the current road surface condition as a split road, obtains vehicle model information such as mass, wheelbase, and center of gravity height, and then... , Steady-state analysis is performed using vehicle model information as input parameters to obtain feedforward values ​​for the optimized steady-state analysis results. These values ​​include the four-wheel braking force and rear wheel steering angle corresponding to the vehicle maintaining straight-line travel and maximizing braking deceleration under different road surface conditions. The longitudinal tire force of the left rear wheel output from the steady-state analysis is used as the feedforward control quantity for the left rear wheel, and the rear wheel steering angle output from the steady-state analysis is also used as the feedforward control quantity. Logical gradual change control is added for smooth correction, outputting the braking force command and rear wheel steering angle command for the left rear wheel. Simultaneously, based on the vehicle model, actual vehicle state information such as vehicle speed, yaw rate, and wheel speed is obtained. Based on the vehicle state information, the braking force of the left front wheel is dynamically calculated through yaw rate closed-loop control, such as sliding mode control. Slip rate control is used to prevent the right wheel from locking up and maintain basic stability. The right front wheel and right rear wheel are located on the low-adhesion side of the road surface, and an ABS control strategy is adopted. By independently and precisely managing each wheel, the yaw control of the front wheel on the high-adhesion side, the feedforward steering and braking of the rear wheel, and the ABS control of the two wheels on the low-adhesion side work together to complete the vehicle's braking control.

[0043] The low-adhesion side employs an anti-lock braking system (ABS) to prevent wheel lock-up and maintain basic stability. The high-adhesion side front wheel utilizes closed-loop control with yaw rate as the feedback target, dynamically adjusting its braking force to actively generate compensating yaw moment and suppress vehicle yaw. The high-adhesion side rear wheel employs feedforward control based on vehicle steady-state analysis, applying the optimal braking force and rear wheel steering angle to assist in stabilizing the vehicle and maximizing the use of the high-adhesion road surface for braking force. Figure 2 middle, The adhesion coefficient is the coefficient of adhesion on the high-adhesion side of the road. The adhesion coefficient is the coefficient of adhesion on the low-adhesion side of the road. Rear wheel steering angle (rad) This represents the expected value of the rear wheel steering angle (rad). The expected value of the longitudinal braking force on the tire (unit: N), in the symbols throughout the text. (Case insensitive) These represent the left front wheel, right front wheel, left rear wheel, and right rear wheel, respectively. This represents the expected value of the longitudinal braking force on the left front wheel, and is consistently expressed throughout the text, so it will not be elaborated on here.

[0044] In some embodiments of this application, step 102, obtaining the yaw angle deviation of the vehicle, and determining the first longitudinal braking force of the first front wheel based on the yaw angle deviation, may specifically include the following steps: Sub-step S11: Obtain the actual yaw angle of the vehicle, and use the difference between the actual yaw rate and the preset expected yaw angle as the yaw angle deviation. Sub-step S12: Obtain the sliding surface corresponding to the yaw angle deviation; Sub-step S13: Determine the first longitudinal braking force of the first front wheel based on the yaw angle deviation and the sliding surface corresponding to the yaw angle deviation.

[0045] In this embodiment, to improve vehicle stability and safety, the braking force distribution, particularly the longitudinal braking force of the first front wheel, is adjusted based on the vehicle's yaw angle deviation. Specifically, the actual yaw angle of the vehicle is obtained, and the difference between the actual yaw angle and the preset desired yaw angle is taken as the yaw angle deviation. The sliding surface corresponding to the yaw angle deviation is obtained, and the first longitudinal braking force of the first front wheel is determined based on the yaw angle deviation and the corresponding sliding surface. Sliding mode control is a nonlinear control method widely used in vehicle dynamics control. The sliding surface is used to guide the dynamic behavior of the system onto a predetermined trajectory, thereby achieving effective control of the yaw angle deviation. The sliding surface is typically a function related to the yaw angle deviation.

[0046] In this embodiment, the actual yaw angle of the vehicle is obtained, and the difference between the actual yaw angle and the preset desired yaw angle is taken as the yaw angle deviation. The actual yaw angle can be obtained through the vehicle's yaw angle sensor, such as a gyroscope or inertial measurement unit (IMU). The yaw angle is the rotation angle of the vehicle around its vertical axis, typically measured in rads. The preset desired yaw angle is an ideal yaw angle calculated based on parameters such as the vehicle's current speed, steering angle, and road adhesion coefficient. The goal of the desired yaw angle is to keep the vehicle stable during braking or steering, avoiding excessive or insufficient yaw. In this embodiment, the desired yaw angle can be set according to actual braking requirements. The yaw angle deviation is the difference between the actual yaw angle and the desired yaw angle. A positive yaw angle deviation indicates that the actual yaw angle is greater than the desired yaw angle, which may lead to oversteering; a negative yaw angle deviation indicates that the actual yaw angle is less than the desired yaw angle, which may lead to understeering.

[0047] In this embodiment, common sliding surfaces include linear and nonlinear sliding surfaces. The purpose of the sliding surface is to guide the yaw angle deviation to zero, thereby making the actual yaw angle of the vehicle approach the desired yaw angle. The quality of the sliding surface design directly affects the stability and response speed of the system. Therefore, based on the yaw angle deviation and the corresponding sliding surface, the first longitudinal braking force of the first front wheel is determined. The first front wheel refers to the front wheel on the side with the higher road surface adhesion coefficient. The longitudinal braking force of the first front wheel can be calculated using a sliding control algorithm based on the yaw angle deviation and the sliding surface. For example, a sliding control law can be used. The sliding control law, through the design of the sliding surface and the approach law, ensures that the system state reaches the sliding surface within a finite time and slides along it to the equilibrium point, achieving robust control against disturbances and uncertainties. In the case of braking on split-road surfaces, the distribution of braking force requires special attention to the adhesion of the wheels on both sides to avoid slippage on one side.

[0048] In practical implementation, a yaw rate closed-loop controller can be designed for the high-adhesion side front wheel (i.e., the first front wheel). Taking sliding mode control as an example of a split road surface with a high adhesion coefficient on the left and a low adhesion coefficient on the right, the braking force of the left front wheel can be controlled. The controlled variable is the braking force of the left front wheel. The control target is the yaw angle. At this time, the front wheel steering angle is zero, so there is no lateral force on the front wheels. Other vehicle state information is measurable known quantities. The vehicle's state equation is:

[0049] in, The derivative of the vehicle's yaw angle, i.e., the yaw rate. The yaw rate is expressed in rad / s. Yaw acceleration (rad / ), The vertical moment of inertia of the vehicle ( ), This is the distance (m) from the rear axle to the center of mass. The left and right track width of the vehicle is 1 meter (m). , These represent the longitudinal and lateral forces acting on the tire, respectively. (The symbols in the text are...) (Case insensitive) These represent the left front wheel, right front wheel, left rear wheel, and right rear wheel, respectively.

[0050] In this embodiment, the actual yaw rate of the vehicle is obtained, and the difference between the actual yaw rate and the preset expected yaw rate is used as the yaw angle deviation. The specific calculation formula is as follows:

[0051] in, For yaw angle deviation, The yaw angle of the vehicle (rad). The desired yaw angle (rad) is the preset target yaw angle used to prevent vehicle yaw. Since it is zero, the yaw rate deviation is zero. This is the actual yaw angle of the vehicle. .

[0052] In this embodiment, the sliding surface corresponding to the yaw angle deviation is obtained. When the sliding surface is reached, both the yaw angle and the yaw rate tend to zero. Specifically, the sliding surface... The settings are shown in the following formula:

[0053] in, For sliding surface, For yaw angle deviation, The rate of change of the yaw angle deviation. To control the adjustable coefficient, The yaw rate is expressed in rad / s. The yaw angle of the vehicle is rad.

[0054] In some embodiments, to avoid chattering of the control quantity when approaching the sliding surface, the following approach rate may also be used:

[0055]

[0056] in, For sliding surface, Let be the rate of convergence of the sliding surface. , To control the adjustable coefficient, It is a saturation function, used in sliding mode control to reduce or eliminate chattering. Yaw acceleration (rad / ), The yaw rate is 0° (rad / s).

[0057] In summary, based on the yaw angle deviation and the corresponding sliding surface, the first longitudinal braking force of the first front wheel is determined. The first front wheel, i.e., the high-adhesion front wheel (e.g., the left front wheel), has a first longitudinal braking force... The unit N is determined by the following formula:

[0058] in, The first longitudinal braking force is for the first front wheel on the first side. The vertical moment of inertia of the vehicle ( ), This is the distance (m) from the rear axle to the center of mass. The left and right track width of the vehicle (m). For sliding surface, It is a saturation function. , , To control the adjustable coefficient, The yaw rate is expressed in rad / s. , These represent the longitudinal and lateral forces acting on the tire, respectively, as indicated by the symbols. These represent the front left wheel, front right wheel, rear left wheel, and rear right wheel, respectively.

[0059] This application embodiment determines the longitudinal braking force of the first front wheel by measuring the yaw angle deviation of the vehicle and designing a sliding surface based on the yaw angle deviation. It then dynamically adjusts the vehicle's braking force distribution, thereby effectively controlling the yaw angle deviation of the vehicle and improving the vehicle's stability and safety under complex road conditions.

[0060] In some embodiments of this application, step 103, determining the second longitudinal braking force and rear wheel steering angle of the first side rear wheel based on a predetermined target braking state of the vehicle, may specifically include the following steps: Sub-step S21: Determine the target braking state of the vehicle through steady-state analysis; the target braking state includes the longitudinal tire force of each wheel and the rear wheel steering angle when the vehicle is traveling straight on a split road surface and the braking deceleration reaches a threshold. Sub-step S22: The longitudinal tire force of the first side rear wheel determined by steady-state analysis is used as the second longitudinal braking force, and the rear wheel steering angle determined by steady-state analysis is used as the rear wheel steering angle of the first side rear wheel.

[0061] In this embodiment, under the braking condition of a split-road surface, the different road adhesion coefficients of the wheels on both sides of the vehicle may cause the vehicle to yaw, skid, or become unstable during braking. To ensure that the vehicle can maintain straight-line travel and that the braking deceleration reaches a predetermined threshold under split-road surface conditions, it is necessary to determine the target braking state of the vehicle through steady-state analysis and adjust the longitudinal braking force and rear wheel steering angle of the first rear wheel accordingly. Using steady-state analysis, a nonlinear programming solver is employed to determine the upper limit of braking for the vehicle under different split-road surface conditions, as well as the corresponding four-wheel braking force and rear wheel steering angle. Thus, based on the predetermined target braking state of the vehicle, the second longitudinal braking force and rear wheel steering angle of the first rear wheel are determined.

[0062] In specific implementation, the target braking state of the vehicle is determined through steady-state analysis. Based on the adhesion of the vehicle on the split road surface, the desired target braking state is determined through steady-state analysis. The target braking state is obtained by steady-state analysis with the goal of the vehicle maintaining straight-line travel and the braking deceleration reaching a threshold, satisfying the constraints of the vehicle dynamics model and tire force model. The target braking state includes the longitudinal tire force of each wheel and the rear wheel steering angle when the vehicle maintains straight-line travel and the braking deceleration reaches the threshold on the split road surface. The longitudinal tire force of the first rear wheel determined by the steady-state analysis is used as the second longitudinal braking force, and the rear wheel steering angle determined by the steady-state analysis is used as the rear wheel steering angle of the first rear wheel.

[0063] In this embodiment, steady-state analysis refers to assuming the vehicle is in a stable state, such as zero yaw rate and zero lateral acceleration, in the vehicle dynamics model. By analyzing parameters such as the longitudinal resultant force, lateral resultant force, and yaw moment of the vehicle, the ideal state of the vehicle under specific working conditions is determined. The target braking state refers to the longitudinal tire force and rear wheel steering angle of each wheel when the vehicle is traveling straight on a split road surface and the braking deceleration reaches a threshold. The determination of the target braking state needs to consider the adhesion coefficient of the first side road surface and the adhesion coefficient of the second side road surface. The adhesion coefficient of the first side road surface is higher than that of the second side road surface. The first side road surface refers to the road surface where one side of the vehicle's wheels are located, and its adhesion coefficient determines the upper limit of the braking force of that side wheel. The second side road surface refers to the road surface where the other side of the vehicle's wheels are located, and its adhesion coefficient determines the upper limit of the braking force of that side wheel.

[0064] In this embodiment, the longitudinal tire force of the first rear wheel determined by steady-state analysis is used as the second longitudinal braking force, and the rear wheel steering angle determined by steady-state analysis is used as the rear wheel steering angle of the first rear wheel. The longitudinal tire force of the first rear wheel determined in the steady-state analysis is the second longitudinal braking force, which is calculated based on the target braking state and is used to ensure that the vehicle maintains straight-line travel on the split-road surface and that the braking deceleration reaches a threshold. The rear wheel steering angle determined in the steady-state analysis is used to adjust the yaw dynamics of the vehicle to ensure that the vehicle maintains straight-line travel on the split-road surface. The magnitude and direction of the rear wheel steering angle are determined according to the target braking state.

[0065] This application embodiment uses steady-state analysis to adjust the longitudinal braking force and rear wheel steering angle of the first rear wheel, ensuring that the vehicle can maintain straight-line travel and achieve maximum braking deceleration on the opposite road surface, thereby effectively preventing yaw and significantly shortening the braking distance.

[0066] In some embodiments of this application, sub-step S21 determines the target braking state of the vehicle through steady-state analysis, which may specifically include: Sub-step 01: Based on the vehicle's longitudinal resultant force, lateral resultant force, and yaw moment, create a vehicle dynamics model that includes rear-wheel steering. Sub-step 02: Create a tire force model based on preset constraints. The constraints include zero yaw rate, zero lateral acceleration in the road coordinate system, and setting the tire longitudinal force and tire lateral force to satisfy the friction circle constraint. Sub-step 03: With the goal of keeping the vehicle moving straight and the braking deceleration reaching the threshold, satisfying the constraints of the vehicle dynamics model and tire force model, steady-state analysis is used to determine the target braking state of the vehicle.

[0067] In this embodiment, the vehicle dynamics model is a mathematical model describing the motion state of a vehicle under different operating conditions. This model typically includes longitudinal motion equations, lateral motion equations, and yaw motion equations. The longitudinal motion equations describe the relationship between the vehicle's longitudinal acceleration and longitudinal resultant force; the lateral motion equations describe the relationship between the vehicle's lateral acceleration and lateral resultant force; and the yaw motion equations describe the relationship between the vehicle's yaw angular velocity and yaw resultant moment. In this embodiment, based on the vehicle's longitudinal resultant force, lateral resultant force, and yaw resultant moment, a vehicle dynamics model incorporating rear-wheel steering is created. Rear-wheel steering refers to the rear wheels participating in adjustments during steering to improve the vehicle's yaw dynamics. Rear-wheel steering can change the vehicle's yaw resultant moment, thereby improving vehicle stability. (Refer to...) Figure 3 The diagram illustrates a vehicle dynamics model in a vehicle braking control method provided in this application embodiment. A vehicle dynamics model incorporating rear-wheel steering is created, as shown below:

[0068] in, Vehicle mass (kg). The longitudinal vehicle speed (m / s) is given in the vehicle coordinate system. For the corresponding acceleration (m / ), The lateral vehicle speed (m / s) is given in the vehicle coordinate system. For the corresponding acceleration (m / ), , These represent the longitudinal force and lateral force (N) acting on the tire, respectively. These represent the left front wheel, right front wheel, left rear wheel, and right rear wheel, respectively. The front wheel steering angle (rad) Rear wheel steering angle (rad) The yaw rate is expressed in rad / s. Yaw acceleration (rad / ), The vertical moment of inertia of the vehicle ( ), This is the distance (m) between the front axle and the center of mass. This is the distance (m) from the rear axle to the center of mass. The left and right track width of the vehicle is 1 meter (m).

[0069] To perform steady-state analysis, a nonlinear programming solver is used to determine the vehicle's braking limit and the corresponding four-wheel braking force and rear wheel steering angle under different split-road conditions. Based on preset constraints, a tire force model is created. Firstly, the following constraints exist under this steady-state condition: zero yaw rate, zero lateral acceleration in the road coordinate system, and the assumption that the tire longitudinal force and tire lateral force satisfy the friction circle constraint, as detailed below:

[0070] in, The yaw rate is expressed in rad / s. Yaw acceleration (rad / ), The front wheel steering angle (rad) The lateral acceleration of the vehicle in the road coordinate system (m / Under the constraints of steady-state analysis, its lateral acceleration and yaw rate are zero, and the longitudinal acceleration is taken from the average road friction coefficient. The determined reference acceleration value is subject to constraints specifying that the acceleration perpendicular to the path is zero, not that the lateral acceleration in the vehicle coordinate system is zero. Therefore, the non-yaw target in the road coordinate system needs to be transformed when converted to the vehicle coordinate system. This transformation is performed using the following formula:

[0071]

[0072] in, The longitudinal acceleration of the vehicle in the road coordinate system (m / ), The longitudinal acceleration of the vehicle in the vehicle coordinate system (m / ), The lateral acceleration of the vehicle in the road coordinate system (m / ), The lateral acceleration of the vehicle in the vehicle coordinate system (m / ), The vehicle's sideslip angle (rad) is the angle of gravity at the center of gravity. The longitudinal vehicle speed (m / s) is given in the vehicle coordinate system. The lateral vehicle speed (m / s) is given in the vehicle coordinate system.

[0073] In this embodiment, the rear wheel steering angle and the braking force of each wheel affect the wheel motion state, and the relationship between system input and output is used to obtain the vehicle dynamics model under the rearward turning condition based on Newton's second law, as follows:

[0074] in, The longitudinal resultant force (N) acting on the vehicle. The resultant lateral force (N) acting on the vehicle. The resultant yaw moment (N / m) experienced by the vehicle. Vehicle mass (kg). The longitudinal acceleration of the vehicle in the vehicle coordinate system (m / ), The lateral acceleration of the vehicle in the vehicle coordinate system (m / ), The longitudinal vehicle speed (m / s) is given in the vehicle coordinate system. For the corresponding acceleration (m / ), The lateral vehicle speed (m / s) is given in the vehicle coordinate system. For the corresponding acceleration (m / ), , These represent the longitudinal force and lateral force (N) acting on the tire, respectively. These represent the left front wheel, right front wheel, left rear wheel, and right rear wheel, respectively. The front wheel steering angle (rad) The yaw rate is expressed in rad / s. Yaw acceleration (rad / ), The vertical moment of inertia of the vehicle ( ), This is the distance (m) between the front axle and the center of mass. This is the distance (m) from the rear axle to the center of mass. The left and right track width of the vehicle is 1 meter (m).

[0075] For ease of solution, a combined slip tire force model can be used in steady-state analysis. Longitudinal slip is characterized by the slip ratio, and lateral slip is defined as a function of the slip ratio with the sideslip angle, as follows:

[0076]

[0077] in, For wheel slip ratio, For longitudinal slippage of the wheel, This is due to lateral slippage of the wheel. The wheel slip angle (rad) The vehicle's sideslip angle (rad) is the angle of gravity at the center of gravity. The front wheel steering angle (rad) is zero. Rear wheel steering angle (rad), tire slip angle for:

[0078] In this embodiment, the tire force model can be represented as follows:

[0079] in, The resultant force (N) exerted by the road on each wheel. For overall tire stiffness, The coefficient of adhesion of the road surface The maximum frictional force (N) is determined. , These represent the longitudinal force and lateral force (N) acting on the tire, respectively. For wheel slip ratio, For longitudinal slippage of the wheel, This refers to lateral slippage of the wheel.

[0080] In this embodiment, the objective is to ensure the vehicle maintains a straight path and the braking deceleration reaches a threshold, satisfying the constraints of the vehicle dynamics model and tire force model. Steady-state analysis determines the target braking state of the vehicle, and the optimization objective is the longitudinal acceleration along the road. The minimum value, i.e., the maximum braking deceleration, means the vehicle has no lateral or yaw motion. And satisfying the above vehicle dynamics model and tire force model description, the problem is solved using a nonlinear programming solver, and the steady-state analysis is specifically expressed as follows:

[0081] Where min is the minimum value, the longitudinal acceleration along the road. The minimum value is denoted by st, where st is the optimization objective and constraint. , These represent the longitudinal force and lateral force (N) acting on the tire, respectively. Rear wheel steering angle (rad) The sideslip angle is the angle at the vehicle's center of gravity. The longitudinal acceleration of the vehicle in the road coordinate system (m / ), The lateral acceleration of the vehicle in the road coordinate system (m / ), The yaw rate is expressed in rad / s. Yaw acceleration (rad / ), The coefficient of adhesion of the road surface The maximum frictional force (N) is determined. For wheel slip ratio, For longitudinal slippage of the wheel, This is due to lateral slippage of the wheel. To preset the safety factor, we can take 0.95.

[0082] This application embodiment utilizes steady-state analysis to determine the braking force and rear wheel steering angle corresponding to the vehicle on a split road surface, ensuring that the vehicle maintains straight-line travel and achieves maximum braking deceleration on a split road surface, thereby effectively preventing yaw and significantly shortening the braking distance.

[0083] In some embodiments of this application, the longitudinal force and lateral force of the tire are set to satisfy the friction circle constraint, including: The friction circle limit of the wheel is determined based on the adhesion coefficient of the first side road surface, the adhesion coefficient of the second side road surface, and the vertical load on the wheel. Based on a preset safety factor, determine the safety boundary of the friction circle limit; Set the safety boundaries of the longitudinal and lateral forces of the tire within the friction circle.

[0084] In this embodiment, the constraint conditions include setting the tire longitudinal force and tire lateral force to satisfy the friction circle constraint, and the total tire force being subjected to the wheel vertical load. (N) and the coefficient of adhesion of the road surface Determined maximum friction force (N) is a constraint, therefore, the longitudinal force and lateral force of the tire are constrained by the friction circle. In this embodiment, the friction circle constraint of the wheel is determined based on the adhesion coefficient of the first side road surface, the adhesion coefficient of the second side road surface, and the vertical load of the wheel. To ensure that the steady-state analysis optimization produces a unique solution, a safety boundary of the friction circle constraint is determined based on a preset safety factor, thereby setting the safety boundary of the longitudinal force and lateral force of the tire within the friction circle constraint.

[0085] In practical implementation, the vertical load on the wheel refers to the vertical support force exerted by the ground on the wheel, which is the vertical force (N) borne by the wheel. The friction circle (also called the adhesion circle) is a concept describing the limit of friction between the tire and the ground. The resultant force (longitudinal force and lateral force) that each tire can generate is finite, and this limit is represented as a circle in a coordinate system. Therefore, in this embodiment, the friction circle limit of the wheel is determined based on the adhesion coefficient of the first side of the road surface, the adhesion coefficient of the second side of the road surface, and the vertical load on the wheel. The friction circle limit can be expressed as:

[0086]

[0087] in, , These represent the longitudinal force and lateral force (N) acting on the tire, respectively. The coefficient of adhesion of the road surface The maximum frictional force (N) is determined. This refers to the coefficient of adhesion of the road surface, including the coefficient of adhesion of the first side of the road surface and the coefficient of adhesion of the second side of the road surface. This refers to the vertical load on the wheel.

[0088] Due to the vertical load of the wheel The migration occurs with changes in the vehicle's longitudinal and lateral accelerations. Under the constraints of steady-state analysis, its lateral acceleration and yaw rate are zero, and the longitudinal acceleration is taken from the average road friction coefficient. Given the determined reference acceleration value, the specific load transfer formula is thus obtained as follows:

[0089] in, The vertical load is for the left front wheel. The vertical load is for the right front wheel. The vertical load is for the left rear wheel. The vertical load is for the right rear wheel. The average road surface friction coefficient, Where is the vehicle mass (kg), and g is the acceleration due to gravity. For the height of the vehicle's center of gravity, This is the distance between the rear axle and the center of mass. This is the distance from the front axle to the center of mass.

[0090] In this embodiment, to ensure that the optimization produces a unique solution, the friction circle constraint should be multiplied by a preset safety factor. , If the value is less than 1, it can be taken as 0.95. Based on the preset safety factor, the safety boundary of the friction circle limit is determined, and the tire longitudinal force and tire lateral force of the wheel are set within the safety boundary of the friction circle limit, as follows:

[0091] in, , These represent the longitudinal force and lateral force (N) acting on the tire, respectively. The coefficient of adhesion of the road surface The maximum frictional force (N) is determined. This is a preset safety factor.

[0092] In this application embodiment, the longitudinal force and lateral force of the tire are set to meet the friction circle constraint to avoid yaw, sideslip or instability caused by tire slippage, so as to better cope with the difference in adhesion coefficient under complex road conditions such as split road surface, and maintain the controllability and stability of the vehicle.

[0093] In some embodiments of this application, step 104, determining the braking clamping force of the second-side dual wheels according to the anti-lock braking control strategy, may specifically include the following steps: Sub-step S31: Obtain the dynamic feedforward compensation determined by the adhesion coefficient of the second side road surface and the longitudinal acceleration of the vehicle. Sub-step S32: Obtain the actual braking clamping force of the second-side dual wheels; Sub-step S33: Determine the braking clamping force of the second-side dual wheels based on dynamic feedforward compensation and actual braking clamping force.

[0094] In this embodiment, under split-road braking conditions, the second wheel of the vehicle, i.e., the one with a lower coefficient of friction, is prone to lock-up, leading to loss of vehicle control or skidding. To prevent the second wheel from locking up, an anti-lock braking control strategy is needed to dynamically adjust the braking clamping force of the two second wheels to ensure the vehicle maintains stability and controllability during braking. In this embodiment, the anti-lock braking control strategy includes wheel slippage detection, brake pressure adjustment, and dynamic feedforward compensation. Wheel slippage is detected by wheel speed sensors. If the wheel slippage rate exceeds a preset threshold, the wheel is considered to be about to lock up. The brake pressure is adjusted according to the wheel slippage. If the wheel is about to lock up, the brake pressure is reduced; if the wheel slippage rate is low, the brake pressure is increased. During braking, the braking clamping force is dynamically adjusted based on the coefficient of friction and longitudinal acceleration to prevent wheel lock-up.

[0095] In this embodiment, the braking clamping force refers to the force applied to the brake pads during emergency braking. It is the force that presses the brake pads against the brake disc to ensure that the vehicle can effectively decelerate or stop during braking.

[0096] First, the dynamic feedforward compensation, determined by the adhesion coefficient of the second-side road surface and the vehicle's longitudinal acceleration, is obtained. Then, the actual braking clamping force of the two wheels on the second side is acquired. Based on the dynamic feedforward compensation and the actual braking clamping force, the braking clamping force of the two wheels on the second side is determined. Dynamic feedforward compensation is a pre-adjustment strategy based on the vehicle's current state (such as adhesion coefficient and longitudinal acceleration). By predicting potential problems during braking, such as wheel lock-up, it adjusts the braking clamping force in advance to avoid wheel lock-up. The actual braking clamping force of the two wheels on the second side refers to the current braking pressure of the two wheels. The magnitude of the braking clamping force directly affects the wheel's braking force and slippage. The actual braking clamping force can be acquired in real time through brake pressure sensors installed in the braking system to monitor the braking pressure of each wheel; details will not be elaborated upon here.

[0097] In this embodiment, the braking clamping force of the second pair of wheels is determined based on dynamic feedforward compensation and actual braking clamping force. The braking clamping force of the second pair of wheels is the target braking clamping force, which is a new braking clamping force calculated based on the actual braking clamping force and dynamic feedforward compensation. It should ensure that the second pair of wheels do not lock up during braking, while maintaining sufficient braking force to ensure that the vehicle can brake effectively.

[0098] In specific implementation, this embodiment can design a bottom-level slip ratio controller for a four-wheel electromechanical braking system to achieve ABS control and braking force tracking. Taking the implementation of a PID (Proportional-Integral-Derivative) controller as an example, the PID controller is a widely used automatic controller in industrial control systems. It consists of three main computational elements: a proportional unit (P), an integral unit (I), and a derivative unit (D). The core of the PID controller is a feedback loop system that adjusts the control output by comparing the difference (error) between the setpoint and the actual measured value, so that the system output reaches or maintains the setpoint. In this embodiment, the PID controller control quantity is:

[0099]

[0100] in, The desired output braking clamping force command (N). The coefficient of adhesion of the road surface (in this formula) (coefficient of adhesion of the second side road surface) and vehicle longitudinal acceleration Dynamic feedforward compensation (N) jointly determined. The clamping force control error (N) is the value of the clamping force. , , These are the control parameters for the proportional unit P, the integral unit I, and the derivative unit D, respectively.

[0101] This application embodiment uses an anti-lock braking control strategy to dynamically adjust the braking clamping force of the two wheels on the low-adhesion side, so that the vehicle does not lock up during braking, while maintaining sufficient braking force to ensure the vehicle maintains stability and controllability under the braking conditions of the road surface.

[0102] In some embodiments of this application, step 105, when the vehicle is in a split-road braking condition, involves braking control of the corresponding wheels based on the first longitudinal braking force, the rear wheel steering angle, the second longitudinal braking force, and the braking clamping force. Specifically, this may include the following steps: Sub-step S41: Apply a first longitudinal braking force to the first front wheel for closed-loop control; Sub-step S42: Apply the second longitudinal braking force to the first side rear wheel and perform logical gradual control on the actual rear wheel steering angle of the first side rear wheel so that the actual rear wheel steering angle smoothly approaches the rear wheel steering angle. Sub-step S43: Control the second-side dual wheels to perform anti-lock braking according to the braking clamping force.

[0103] In this embodiment, under the braking condition of a split-road surface, the different road adhesion coefficients of the wheels on both sides of the vehicle may cause yaw, sideslip, or instability during braking. To ensure that the vehicle can maintain straight-line travel and achieve a predetermined braking deceleration threshold on a split-road surface, this embodiment utilizes the rapid independent adjustment capability of the electromechanical braking system and the fully active control of the rear wheel steering to achieve independent control of each wheel. The yaw stabilization task is assigned to the front and rear wheels on the high-adhesion side, while the two wheels on the low-adhesion side focus on anti-lock braking, effectively preventing yaw while significantly shortening the braking distance.

[0104] In this embodiment, refer to Figure 5This diagram illustrates a flowchart of a vehicle braking control method provided in an embodiment of this application. Based on the adhesion coefficients of the high-adhesion and low-adhesion sides of the road surface, offline steady-state analysis is performed using vehicle model information. The optimization objective is to maintain straight-line driving while maximizing braking deceleration. A nonlinear programming solver is used to solve the problem, and the output is a steady-state analysis optimization feedforward value, including the longitudinal braking force of the rear wheel on the high-adhesion side, the rear wheel steering angle, and the braking force distribution of other wheels. Logical gradual control is applied to the rear wheel steering angle, limiting the rate of change to prevent excessive rear wheel rotation that could lead to vehicle instability. This ensures the rear wheel steering angle approaches the target value at a safe speed. Simultaneously, compensation is received from the closed-loop control of the yaw angle of the front wheel on the high-adhesion side, and the final rear wheel steering angle is output to the vehicle model. Using the vehicle yaw angle as the feedback control target, with a desired yaw angle of zero, sliding mode control is used to dynamically calculate the deviation between the actual and desired yaw angles. The longitudinal braking force of the front wheel on the high-adhesion side is output, and a compensation signal is simultaneously output to the logic correction controller to coordinate the rear wheel steering angle. The vehicle model calculates the actual motion state of the vehicle, such as yaw angle, yaw rate, lateral acceleration, and longitudinal acceleration, based on inputs such as longitudinal braking force, rear wheel steering angle, and braking force of other wheels. The calculation module feeds back the state information output by the vehicle model to the closed-loop control of the yaw angle of the front wheel on the high-adhesion side, forming a closed-loop feedback loop.

[0105] The system employs an anti-lock braking system (ABS) on the low-adhesion side to prevent wheel lock-up and maintain basic stability. The high-adhesion side front wheels utilize closed-loop control with yaw rate as the feedback target. By dynamically adjusting their braking force, they actively generate compensating yaw moments to suppress vehicle yaw. The high-adhesion side rear wheels employ feedforward control based on vehicle steady-state analysis, applying the optimal braking force and rear wheel steering angle to assist in vehicle stability and maximize the use of the high-adhesion road surface for braking force. Specifically, when the vehicle is braking on a split-road surface, a first longitudinal braking force is applied to the first front wheel using closed-loop control, while a second longitudinal braking force is applied to the first rear wheel. The actual rear wheel steering angle of the first rear wheel is logically and gradually controlled to smoothly approach the actual rear wheel steering angle, and the second pair of wheels are controlled to perform anti-lock braking according to the braking clamping force.

[0106] In this embodiment, the longitudinal braking force of the first front wheel is dynamically adjusted to ensure vehicle stability on split-plane surfaces. The first longitudinal braking force is calculated based on the yaw angle deviation and is used to adjust the vehicle's yaw dynamics, preventing oversteer or understeer. Closed-loop control is achieved by applying the first longitudinal braking force to the first front wheel. The second longitudinal braking force and rear wheel steering angle of the first rear wheel are pre-calculated to adjust the vehicle's braking and steering dynamics in advance, ensuring the vehicle maintains straight-line travel on split-plane surfaces. The second longitudinal braking force is calculated based on the target braking state determined by steady-state analysis and is used to ensure the vehicle maintains straight-line travel and that the braking deceleration reaches a threshold on split-plane surfaces. The rear wheel steering angle is calculated based on the target braking state determined by steady-state analysis and is used to adjust the vehicle's yaw dynamics, ensuring the vehicle maintains straight-line travel on split-plane surfaces. To prevent the second pair of wheels from locking up during braking, the brake clamping force is dynamically adjusted to achieve anti-lock braking, ensuring the vehicle maintains stability and controllability during braking.

[0107] This application embodiment manages each wheel independently and precisely, and uses closed-loop and feedforward control for the front and rear wheels on the high-adhesion side respectively, allowing the two wheels on the low-adhesion side to focus on anti-lock braking. This enables the front wheel yaw control, rear wheel feedforward steering and braking, and ABS control on the low-adhesion side to work together to form an efficient collaborative mechanism, which effectively prevents yaw while significantly shortening the braking distance.

[0108] Reference Figure 6 The diagram shows a structural schematic of a vehicle braking control device according to an embodiment of this application. The device includes: The identification module 201 is used to monitor the adhesion coefficient of the road surface where the vehicle is located and to identify whether the vehicle is in a split road braking condition; wherein, the split road braking condition is that the left and right sides of the wheel are on the first side road and the second side road, and the adhesion coefficient of the first side road is higher than the adhesion coefficient of the second side road. The first determining module 202 is used to obtain the yaw angle deviation of the vehicle and determine the first longitudinal braking force of the first front wheel based on the yaw angle deviation. The second determining module 203 is used to determine the second longitudinal braking force and the rear wheel steering angle of the first side rear wheel according to the predetermined target braking state of the vehicle; wherein, the target braking state is obtained by steady-state analysis with the goal of keeping the vehicle moving straight and the braking deceleration reaching a threshold, satisfying the constraints of the vehicle dynamics model and the tire force model; The third determining module 204 is used to determine the braking clamping force of the second side dual wheels according to the anti-lock braking control strategy; Control module 205 is used to control the braking of the corresponding wheels based on the first longitudinal braking force, the rear wheel steering angle, the second longitudinal braking force, and the braking clamping force when the vehicle is in the braking condition of the split road surface.

[0109] Optionally, the first determining module 202 includes: The first acquisition submodule is used to acquire the actual yaw rate of the vehicle and use the difference between the actual yaw rate and the preset expected yaw rate as the yaw angle deviation. The second acquisition submodule is used to acquire the sliding surface corresponding to the yaw angle deviation; The first determining submodule is used to determine the first longitudinal braking force of the first front wheel based on the yaw angle deviation and the sliding surface corresponding to the yaw angle deviation.

[0110] Optionally, the second determining module 203 includes: The steady-state analysis submodule is used to determine the target braking state of the vehicle through steady-state analysis; the target braking state includes the longitudinal tire force of each wheel and the rear wheel steering angle when the vehicle is traveling straight on a split road surface and the braking deceleration reaches a threshold. The second determining submodule is used to take the longitudinal tire force of the first side rear wheel determined by steady-state analysis as the second longitudinal braking force, and to take the rear wheel steering angle determined by the steady-state analysis as the rear wheel steering angle of the first side rear wheel.

[0111] Optionally, the steady-state analysis submodule includes: The first creation unit is used to create a vehicle dynamics model that includes rear-wheel steering based on the vehicle's longitudinal resultant force, lateral resultant force, and yaw moment. The second creation unit is used to create a tire force model according to preset constraints; the constraints include zero yaw rate, zero lateral acceleration in the road coordinate system, and setting the tire longitudinal force and tire lateral force to satisfy the friction circle constraint. The determination unit is used to determine the target braking state of the vehicle through steady-state analysis, with the goal of keeping the vehicle moving straight and the braking deceleration reaching a threshold value, satisfying the constraints of the vehicle dynamics model and the tire force model.

[0112] Optionally, the second creation unit further includes: The first determining sub-unit is used to determine the friction circle limit of the wheel based on the adhesion coefficient of the first side road surface, the adhesion coefficient of the second side road surface, and the vertical load of the wheel. The second determining subunit is used to determine the safety boundary of the friction circle limit based on a preset safety factor; The processing subunit is used to set the longitudinal and lateral forces of the tires at the safety boundaries defined by the friction circle.

[0113] Optionally, the third determining module 204 includes: The third acquisition submodule is used to acquire the dynamic feedforward compensation determined by the adhesion coefficient of the second side road surface and the longitudinal acceleration of the vehicle. The fourth acquisition submodule is used to acquire the actual braking clamping force of the two wheels on the second side; The third determining submodule is used to determine the braking clamping force of the second side dual wheels based on the dynamic feedforward compensation and the actual braking clamping force.

[0114] Optionally, the control module 205 includes: The first control submodule is used to perform closed-loop control on the first side front wheel to apply the first longitudinal braking force; The second control submodule is used to apply the second longitudinal braking force to the first side rear wheel and to perform logical gradual control on the actual rear wheel steering angle of the first side rear wheel so that the actual rear wheel steering angle smoothly approaches the rear wheel steering angle. The third control submodule is used to control the second-side dual wheels to perform anti-lock braking according to the braking clamping force.

[0115] The vehicle braking control device provided in this application embodiment can realize the various processes of the vehicle braking control method in the above embodiments of this application. To avoid repetition, it will not be described again here.

[0116] The vehicle braking control device provided in this application embodiment identifies whether the vehicle is in a split-road braking condition by monitoring the adhesion coefficient of the road surface on which the vehicle is located. In the split-road braking condition, the left and right sides of the wheels are on a first side road and a second side road, with the adhesion coefficient of the first side road being higher than that of the second side road. The yaw angle deviation of the vehicle is obtained, and based on the yaw angle deviation, the first longitudinal braking force of the first front wheel is determined. Based on a predetermined target braking state of the vehicle, the second longitudinal braking force and rear wheel steering angle of the first rear wheel are determined. The target braking state is obtained through steady-state analysis with the goal of maintaining straight-line travel and achieving a braking deceleration threshold that satisfies the constraints of the vehicle dynamics model and tire force model. Based on the anti-lock braking strategy, the braking clamping force of the second dual wheels is determined. When the vehicle is in a split-road braking condition, braking control is performed on the corresponding wheels based on the first longitudinal braking force, rear wheel steering angle, second longitudinal braking force, and braking clamping force. In this embodiment, when the vehicle is identified to be in a complex split-road condition, closed-loop and feedforward control are used for the front and rear wheels on the high-adhesion side, respectively, while the dual wheels on the low-adhesion side are focused on anti-lock braking control. By managing each wheel independently and precisely, the yaw control of the front wheels on the high-adhesion side, the feedforward steering and braking of the rear wheels, and the ABS control of the dual wheels on the low-adhesion side work together to effectively prevent yaw while significantly shortening the braking distance. This greatly improves the braking performance optimization on split-road surfaces, meets the safety and braking efficiency requirements on split-road surfaces, and further enhances the vehicle's braking performance on split-road surfaces.

[0117] Reference Figure 7 This application also provides an electronic device, such as... Figure 7 As shown, it includes a processor 301, a communication interface 302, a memory 303, and a communication bus 304, wherein the processor 301, the communication interface 302, and the memory 303 communicate with each other through the communication bus 304. Processor 301, memory 303 for storing processor-executable instructions; The processor 301 is configured to execute the instructions to implement the vehicle braking control method described below: Monitor the coefficient of friction of the road surface where the vehicle is located to identify whether the vehicle is in a split-road braking condition; wherein, the split-road braking condition is when the left and right sides of the wheel are on the first side road surface and the second side road surface, and the coefficient of friction of the first side road surface is higher than the coefficient of friction of the second side road surface. Obtain the yaw angle deviation of the vehicle, and determine the first longitudinal braking force of the first front wheel based on the yaw angle deviation; Based on the predetermined target braking state of the vehicle, the second longitudinal braking force and the rear wheel steering angle of the first side rear wheel are determined; wherein, the target braking state is obtained by steady-state analysis with the goal of keeping the vehicle moving straight and the braking deceleration reaching a threshold, satisfying the constraints of the vehicle dynamics model and the tire force model; Based on the anti-lock braking system (ABS) strategy, determine the braking clamping force of the second-side dual wheels; When the vehicle is in the braking condition of the split road surface, braking control is performed on the corresponding wheels according to the first longitudinal braking force, the rear wheel steering angle, the second longitudinal braking force, and the braking clamping force.

[0118] The communication bus mentioned above can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. This communication bus can be divided into address bus, data bus, control bus, etc. For ease of illustration, only one thick line is used to represent it in the diagram, but this does not mean that there is only one bus or one type of bus.

[0119] The communication interface is used for communication between the aforementioned terminal and other devices.

[0120] The memory may include random access memory (RAM) or non-volatile memory, such as at least one disk storage device. Optionally, the memory may also be at least one storage device located remotely from the aforementioned processor.

[0121] The processors mentioned above can be general-purpose processors, including central processing units (CPUs), network processors (NPs), etc.; they can also be digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0122] In another embodiment provided in this application, a computer-readable storage medium is also provided, on which a computer program is stored, which, when executed by a processor, implements any of the vehicle braking control methods described in the above embodiments.

[0123] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid state disk (SSD)).

[0124] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0125] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0126] The above description is merely a preferred embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application are included within the scope of protection of this application.

Claims

1. A vehicle braking control method, characterized in that, The method includes: Monitor the coefficient of friction of the road surface where the vehicle is located to identify whether the vehicle is in a split-road braking condition; wherein, the split-road braking condition is when the left and right sides of the wheel are on the first side road surface and the second side road surface, and the coefficient of friction of the first side road surface is higher than the coefficient of friction of the second side road surface. Obtain the yaw angle deviation of the vehicle, and determine the first longitudinal braking force of the first front wheel based on the yaw angle deviation; Based on the predetermined target braking state of the vehicle, the second longitudinal braking force and the rear wheel steering angle of the first side rear wheel are determined; wherein, the target braking state is obtained by steady-state analysis with the goal of keeping the vehicle moving straight and the braking deceleration reaching a threshold, satisfying the constraints of the vehicle dynamics model and the tire force model; Based on the anti-lock braking system (ABS) strategy, determine the braking clamping force of the second-side dual wheels; When the vehicle is in the braking condition of the split road surface, braking control is performed on the corresponding wheels according to the first longitudinal braking force, the rear wheel steering angle, the second longitudinal braking force, and the braking clamping force.

2. The method according to claim 1, characterized in that, The step of acquiring the vehicle's yaw angle deviation and determining the first longitudinal braking force of the first front wheel based on the yaw angle deviation includes: Obtain the actual yaw rate of the vehicle, and use the difference between the actual yaw rate and the preset expected yaw rate as the yaw angle deviation; Obtain the sliding surface corresponding to the yaw angle deviation; The first longitudinal braking force of the first front wheel is determined based on the yaw angle deviation and the sliding surface corresponding to the yaw angle deviation.

3. The method according to claim 1, characterized in that, The step of determining the second longitudinal braking force and rear wheel steering angle of the first rear wheel based on a predetermined target braking state of the vehicle includes: The target braking state of the vehicle is determined by steady-state analysis; the target braking state includes the longitudinal tire force of each wheel and the rear wheel steering angle when the vehicle is traveling straight on a split road surface and the braking deceleration reaches a threshold. The longitudinal tire force of the first side rear wheel determined by the steady-state analysis is used as the second longitudinal braking force, and the rear wheel steering angle determined by the steady-state analysis is used as the rear wheel steering angle of the first side rear wheel.

4. The method according to claim 3, characterized in that, The determination of the target braking state of the vehicle through steady-state analysis includes: Based on the vehicle's longitudinal resultant force, lateral resultant force, and yaw moment, a vehicle dynamics model incorporating rear-wheel steering is created. A tire force model is created based on preset constraints; the constraints include zero yaw rate, zero lateral acceleration in the road coordinate system, and setting the tire longitudinal force and tire lateral force to satisfy the friction circle constraint. With the goal of keeping the vehicle moving straight and the braking deceleration reaching a threshold, satisfying the constraints of the vehicle dynamics model and tire force model, steady-state analysis is used to determine the target braking state of the vehicle.

5. The method according to claim 4, characterized in that, The setting of tire longitudinal force and tire lateral force to satisfy friction circle constraint includes: The friction circle limit of the wheel is determined based on the adhesion coefficient of the first side road surface, the adhesion coefficient of the second side road surface, and the vertical load on the wheel. The safety boundary of the friction circle limit is determined based on a preset safety factor; The longitudinal and lateral forces of the tires are set at safe boundaries defined by the friction circle.

6. The method according to claim 1, characterized in that, The determination of the braking clamping force of the second-side dual wheels according to the anti-lock braking control strategy includes: Obtain dynamic feedforward compensation determined by the adhesion coefficient of the second side road surface and the longitudinal acceleration of the vehicle; Obtain the actual braking clamping force of the second-side dual wheels; The braking clamping force of the second-side dual wheels is determined based on the dynamic feedforward compensation and the actual braking clamping force.

7. The method according to claim 1, characterized in that, The braking control of the corresponding wheel based on the first longitudinal braking force, the rear wheel steering angle, the second longitudinal braking force, and the braking clamping force includes: The first longitudinal braking force is applied to the first front wheel on the first side for closed-loop control. The second longitudinal braking force is applied to the first side rear wheel, and the actual rear wheel steering angle of the first side rear wheel is logically gradually controlled so that the actual rear wheel steering angle smoothly approaches the rear wheel steering angle. Control the second-side dual wheels to perform anti-lock braking according to the braking clamping force.

8. A vehicle braking control device, characterized in that, The device includes: The identification module is used to monitor the adhesion coefficient of the road surface where the vehicle is located and to identify whether the vehicle is in a split-road braking condition; wherein, the split-road braking condition is that the left and right sides of the wheels are on the first side road surface and the second side road surface, and the adhesion coefficient of the first side road surface is higher than the adhesion coefficient of the second side road surface. The first determining module is used to obtain the yaw angle deviation of the vehicle and determine the first longitudinal braking force of the first front wheel based on the yaw angle deviation. The second determining module is used to determine the second longitudinal braking force and the rear wheel steering angle of the first side rear wheel based on the predetermined target braking state of the vehicle; wherein, the target braking state is obtained by steady-state analysis with the goal of keeping the vehicle moving straight and the braking deceleration reaching a threshold, satisfying the constraints of the vehicle dynamics model and the tire force model; The third determining module is used to determine the braking clamping force of the second-side dual wheels based on the anti-lock braking control strategy; The control module is used to control the braking of the corresponding wheels based on the first longitudinal braking force, the rear wheel steering angle, the second longitudinal braking force, and the braking clamping force when the vehicle is in the braking condition of the split road surface.

9. An electronic device, characterized in that, include: processor; Memory used to store processor-executable instructions; The processor is configured to execute the instructions to implement the vehicle braking control method as described in any one of claims 1 to 7.

10. A readable storage medium, characterized in that, The readable storage medium stores a computer program that, when executed by a processor, implements the vehicle braking control method as described in any one of claims 1 to 7.

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