Vehicle braking control method, controller and vehicle

Abstract

The invention relates to the technical field of vehicle braking control, in particular to a vehicle braking control method, a controller and a vehicle. The method comprises the steps that multiple actual stability parameters of the vehicle in the braking process are obtained; and the braking torque of the vehicle is adjusted step by step according to the relation between each actual stability parameter and the corresponding preset stability parameter in sequence, the phenomenon of wheel locking or sideslip caused by large adjustment of the braking torque is avoided, and the stability and safety of the vehicle in various braking scenes are effectively improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of vehicle braking control, and specifically, to a vehicle braking control method, a controller, and a vehicle. Background Art

[0002] With the progress of electronic control technology, it has become crucial to maintain the dynamic stability of a vehicle during braking. In some braking situations, due to the influence of various factors such as road surface conditions, vehicle load, vehicle speed, and wheel characteristics, the vehicle may skid or get out of control, which will have an adverse impact on the stability and safety of the vehicle.

[0003] In the existing technology, the stability control during vehicle braking usually determines the required braking force by monitoring the slip ratio or yaw angular velocity, and then adjusts the braking torque of each wheel accordingly to meet this requirement. However, in the case of a sharp increase in the braking force demand, the adjustment of the vehicle's braking torque may be too drastic, which may cause the vehicle to experience wheel lock-up or lateral sliding, reducing the safety and stability of the vehicle during braking. On the other hand, the vehicle may trigger the direct intervention of the ABS (Anti-lock Braking System) or ESC (Electronic Stability Control) braking control, reducing the stability and safety of the vehicle. Therefore, a more refined control strategy is needed to ensure the stability and safety of the vehicle in various braking scenarios. Summary of the Invention

[0004] The purpose of the present disclosure is to provide a vehicle braking control method, a controller, and a vehicle.

[0005] To achieve the above purpose, the present disclosure provides a vehicle braking control method, and the method includes: Obtain a plurality of actual stability parameters of the vehicle during braking; Gradually adjust the braking torque of the vehicle according to the relationship between each actual stability parameter and its corresponding preset stability parameter in sequence.

[0006] Optionally, the method further includes: Obtain the driving state parameters of the vehicle during braking; Determine an adjustment coefficient corresponding to each actual stability parameter according to the driving state parameters; The step of gradually adjusting the braking torque of the vehicle according to the relationship between each actual stability parameter and its corresponding preset stability parameter in sequence includes: Successively adjust the braking torque of the vehicle step by step according to the relationship between each of the actual stability parameters and their respective corresponding preset stability parameters through their respective corresponding preset adjustment coefficients.

[0007] Optionally, the multiple actual stability parameters include an actual slip ratio, an actual yaw rate, and an actual sideslip angle of the center of mass, and the preset stability parameters include a preset slip ratio corresponding to the actual slip ratio, a preset yaw rate corresponding to the actual yaw rate, and a preset sideslip angle of the center of mass corresponding to the actual sideslip angle of the center of mass; The successively adjusting the braking torque of the vehicle step by step according to the relationship between each of the actual stability parameters and their respective corresponding preset stability parameters through their respective corresponding adjustment coefficients includes: Adjust the braking torque at the first level through the adjustment coefficient corresponding to the actual slip ratio according to the relationship between the actual slip ratio and the preset slip ratio; After the first-level adjustment is completed, adjust the braking torque at the second level through the adjustment coefficient corresponding to the actual yaw rate according to the relationship between the actual yaw rate and the preset yaw rate; After the second-level adjustment is completed, adjust the braking torque at the third level through the adjustment coefficient corresponding to the actual sideslip angle of the center of mass according to the relationship between the actual sideslip angle of the center of mass and the preset sideslip angle of the center of mass.

[0008] Optionally, the driving state parameters include a longitudinal vehicle speed and a steering wheel angle, and determining the adjustment coefficient corresponding to each of the actual stability parameters according to the driving state parameters includes: Determine a first adjustment coefficient corresponding to the actual slip ratio according to the longitudinal vehicle speed; and Determine a second adjustment coefficient corresponding to the actual yaw rate and a third adjustment coefficient corresponding to the actual sideslip angle of the center of mass according to the steering wheel angle.

[0009] Optionally, the adjusting the braking torque at the first level through the adjustment coefficient corresponding to the actual slip ratio according to the relationship between the actual slip ratio and the preset slip ratio includes: When the actual slip ratio of the target wheel is greater than the preset slip ratio, reduce the braking torque of the target wheel through the first adjustment coefficient until the actual slip ratio of the target wheel is less than or equal to the preset slip ratio, and determine that the first-level adjustment of the braking torque is completed, where the target wheel is any wheel of the vehicle.

[0010] Optionally, the second - stage adjustment of the braking torque according to the relationship between the actual yaw rate and the preset yaw rate, by using an adjustment coefficient corresponding to the actual yaw rate, includes: When the actual yaw rate of the vehicle is greater than the preset yaw rate, increase the braking torque of the first target - side wheels by the second adjustment coefficient, and return to execute the first - stage adjustment until the actual yaw rate of the vehicle is less than or equal to the preset yaw rate, and determine that the second - stage adjustment of the braking torque is completed. The orientation of the first target side is opposite to the direction of the actual yaw rate.

[0011] Optionally, the third - stage adjustment of the braking torque according to the relationship between the actual sideslip angle of the center of mass and the preset sideslip angle of the center of mass, by using an adjustment coefficient corresponding to the actual sideslip angle of the center of mass, includes: When the actual sideslip angle of the center of mass of the vehicle is greater than the preset sideslip angle of the center of mass, increase the braking torque of the second target - side wheels by the third adjustment coefficient, and return to execute the first - stage adjustment until the actual sideslip angle of the center of mass of the vehicle is less than or equal to the preset sideslip angle of the center of mass, and determine that the third - stage adjustment of the braking torque is completed. The orientation of the second target side is opposite to the direction of the actual sideslip angle of the center of mass.

[0012] Optionally, the method further includes: When the longitudinal vehicle speed is less than a preset speed threshold and the gear of the vehicle is in the parking gear, control the wheel of the vehicle to unload the braking torque.

[0013] Optionally, the vehicle includes a first electric - motor brake, a second electric - motor brake, and a hydraulic brake. The first electric - motor brake corresponds to the front - axle wheels of the vehicle, and the second electric - motor brake corresponds to the rear - axle wheels of the vehicle. Before obtaining multiple actual stability parameters during the braking process of the vehicle, the method further includes: Determine the total braking torque corresponding to the vehicle speed and the depth of the brake pedal; Distribute the total braking torque to the front - axle wheels and the rear - axle wheels of the vehicle according to a preset distribution ratio; Sequentially distribute the braking torque allocated to the front - axle wheels to the first electric - motor brake and the hydraulic brake, and sequentially distribute the braking torque allocated to the rear - axle wheels to the second electric - motor brake and the hydraulic controller.

[0014] The present disclosure also provides a controller, including: A memory storing a computer program thereon; A processor for executing the computer program in the memory to implement the vehicle braking control method provided by the present disclosure.

[0015] The present disclosure also provides a vehicle, on which a controller as provided by the present disclosure is configured.

[0016] Through the above technical solutions, by successively adjusting the braking torque of the vehicle step by step according to the relationship between each actual stability parameter and its corresponding preset stability parameter, the stability of the vehicle during braking can be accurately controlled, avoiding the phenomenon of wheel locking or skidding caused by a large adjustment of the braking torque. At the same time, the abnormal intervention of the ABS and ESC is reduced, effectively improving the stability and safety of the vehicle in various braking scenarios.

[0017] Other features and advantages of the present disclosure will be described in detail in the subsequent specific implementation part. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific implementation, they are used to explain the present disclosure, but do not constitute a limitation to the present disclosure. In the drawings: Figure 1 is a flowchart of the steps of a vehicle braking control method proposed in an exemplary embodiment of the present disclosure.

[0019] Figure 2 is a schematic structural diagram of a braking system of a three-motor vehicle proposed in an exemplary embodiment of the present disclosure.

[0020] Figure 3 is a flowchart of the steps of a vehicle braking control method proposed according to an exemplary embodiment of the present disclosure.

[0021] Figure 4 is a block diagram of a vehicle braking control device proposed according to an exemplary embodiment of the present disclosure.

[0022] Figure 5 is a block diagram of a vehicle proposed according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The following will describe in detail the specific implementation of the present disclosure with reference to the drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0024] [[ID=4l]] Figure 1 is a flowchart of the steps of a vehicle braking control method proposed in an exemplary embodiment of the present disclosure. Refer to Figure 1 As shown, the method includes the following steps: In step S11, multiple actual stability parameters of the vehicle during braking are obtained.

[0025] Among them, each stability parameter of the vehicle can reflect the dynamic stability of the vehicle during braking from different perspectives. For example, it can reflect the grip and lateral stability of the vehicle. By monitoring the real-time actual stability parameters of the vehicle, the braking torque of the vehicle can be dynamically adjusted in a timely and continuous manner.

[0026] In one implementation, the stability parameters of the vehicle include the yaw rate, center of gravity side slip angle, lateral acceleration of the vehicle, and the slip ratio of each wheel. Among them, the yaw rate and lateral acceleration are used to reflect the lateral stability of the vehicle. An excessive yaw rate may mean that the vehicle is about to experience an out-of-control skid, and an excessive lateral acceleration may cause the vehicle to deviate from the normal driving trajectory. The slip ratio of the wheel is used to reflect the adhesion between the wheel and the ground. An unreasonable slip ratio of the wheel will affect the braking efficiency and stability of the vehicle. The center of gravity side slip angle is a comprehensive parameter that reflects the steering characteristics, driving stability of the vehicle, and the adhesion between the wheel and the ground.

[0027] It should be noted that the vehicle braking control method provided in this disclosure can be applied to electric vehicles and hybrid vehicles. The braking system of the vehicle can include at least multiple of a hydraulic braking system, a mechanical braking system, a pneumatic braking system, and an electric motor braking system. Among them, the electric motor braking system can include multiple electric motors.

[0028] Exemplarily, Figure 2 is a schematic structural diagram of a braking system of a three-motor vehicle proposed according to an exemplary embodiment. Refer to Figure 2As shown, it includes a main brake controller, a front motor controller, a front motor, a left rear motor controller, a left rear motor, a right rear motor controller, a right rear motor, a hydraulic controller, a hydraulic master cylinder, a left front caliper, a right front caliper, a left rear caliper, a right rear caliper, a left front wheel speed sensor, a right front wheel speed sensor, a left rear wheel speed sensor, a right rear wheel speed sensor, a yaw rate sensor, and a brake pedal travel sensor. Among them, the left front wheel speed sensor is used to collect the wheel speed information of the left front wheel, the right front wheel speed sensor is used to collect the wheel speed information of the right front wheel, the left rear wheel speed sensor is used to collect the wheel speed information of the left rear wheel, and the right rear wheel speed sensor is used to collect the wheel speed information of the right rear wheel. The yaw rate sensor collects the actual yaw angular velocity, longitudinal acceleration, and lateral acceleration of the vehicle. The brake pedal travel sensor is used to collect the brake pedal depth corresponding to the driver stepping on the brake pedal. The main brake controller is used to receive the wheel speed information collected by the four wheel speed sensors, the actual yaw angular velocity collected by the yaw rate sensor, and the brake pedal depth collected by the brake pedal travel sensor, and calculates the vehicle speed (lateral vehicle speed and longitudinal vehicle speed), the slip ratio of each wheel, and the actual center of mass side slip angle through the wheel speed information of the four wheels, the actual yaw angular velocity of the vehicle, longitudinal acceleration, and lateral acceleration.

[0029] The front motor controller receives the front motor braking torque information sent by the main brake controller and controls the front motor to output this braking torque. The front motor outputs the braking torque to the left front wheel and the right front wheel. The left rear motor controller receives the left rear motor braking torque information sent by the main brake controller and controls the left rear motor to output this braking torque. The left rear motor outputs the braking torque to the left rear wheel. The right rear motor controller receives the right rear motor braking torque information sent by the main brake controller and controls the right rear motor to output this braking torque. The right rear motor outputs the braking torque to the right rear wheel. The hydraulic brake controller receives the four-wheel hydraulic braking torque information sent by the main brake controller and controls the left front caliper, the right front caliper, the left rear caliper, and the right rear caliper to generate corresponding braking torques that act on the left front wheel, the right front wheel, the left rear wheel, and the right rear wheel respectively. In addition, the vehicle also includes a gear sensor and a steering wheel sensor that are communicatively connected to the main brake controller. Among them, the gear sensor is used to monitor the gear of the vehicle, and the steering wheel sensor is used to monitor the steering wheel angle.

[0030] In step S12, the braking torque of the vehicle is adjusted step by step according to the relationship between each actual stability parameter and its corresponding preset stability parameter.

[0031] Among them, the preset stability parameter is a calibration parameter that can ensure stable braking of the vehicle under ideal conditions, and the preset stability parameter can be obtained based on experimental research, road tests, and theoretical analysis.

[0032] It should be noted that during the vehicle braking process, when the wheels tend to lock or there is a risk of loss of control, ABS and ESC will intervene in vehicle control, resulting in the exit of normal braking and the inability to ensure the vehicle's handling performance and driving experience. Therefore, the preset stability parameter can be determined according to the stability parameter corresponding to the trigger boundary of ABS and ESC, and the preset stability parameter is usually smaller than the stability parameter corresponding to the above boundary trigger.

[0033] Therefore, according to the relationship between the actual stability parameter of the vehicle and the preset stability parameter, the braking torque of the vehicle can be adjusted in advance before the vehicle body yaws or the wheels lock.

[0034] Exemplarily, for any stability parameter, if the actual stability parameter is greater than the preset stability parameter, it usually indicates that the current braking state of the vehicle is too "aggressive", resulting in poor vehicle stability. At this time, the braking torque can be reduced to slow down the braking rate of the vehicle and make the driving state of the vehicle develop in a more stable direction. On the contrary, if the actual stability parameter is less than the preset stability parameter, it means that the braking effect of the vehicle is not ideal and the braking function is not fully exerted. At this time, it is necessary to appropriately increase the braking torque to strengthen the braking effect.

[0035] In one implementation, the adjustment range of the vehicle's braking torque can be determined according to the deviation between the actual stability parameter and the preset stability parameter. The greater the deviation, the greater the difference between the current braking state of the vehicle and the ideal state, and then the adjustment range of the braking torque needs to be increased accordingly. For example, when the difference between the actual yaw rate and the preset yaw rate is greater than the preset difference, it is necessary to significantly reduce the braking torque of the inner wheel or increase the braking torque of the outer wheel to correct the unstable state of the vehicle as soon as possible; if the deviation between the two is less than or equal to the preset difference, only a small adjustment of the braking torque or no adjustment of the braking torque is required.

[0036] In addition, a sudden large change in the vehicle's braking torque may trigger a series of chain reactions, such as causing the wheels to lock and the vehicle to lose control. Therefore, the adjustment method of the braking torque can be a step-by-step adjustment, which means that the braking torque is not adjusted significantly at one time, but is adjusted step by step and hierarchically.

[0037] In one embodiment, the step-by-step adjustment of the vehicle's braking torque can be carried out through the following aspects: On the one hand, the sequential step-by-step adjustment of the braking torque includes multiple adjustments of the vehicle's braking torque with different adjustment ranges.

[0038] For example, when a certain actual stability parameter of the vehicle is greater than the preset stability parameter, first, a relatively small preliminary adjustment is made to the braking torque. This process continues, continuously adjusting according to the relationship between the actually monitored actual stability parameter and the preset stability parameter until all the actual stability parameters of the vehicle are as close as possible to their respective preset stability parameters. At this time, the braking torque of the vehicle is adjusted to a suitable value that can ensure good stability of the vehicle during braking, achieving stable control of the vehicle braking process.

[0039] On the other hand, making step-by-step adjustments to the braking torque in sequence also includes adjusting the braking torque of the vehicle according to different stability parameters in order of adjustment priority.

[0040] In one implementation, the adjustment priority can be determined by at least one of the driving mode of the vehicle, road surface conditions, vehicle type, and braking scenario. The following gives an exemplary description of different adjustment priorities for the slip ratio, yaw rate, and sideslip angle of the center of mass among the stability parameters.

[0041] Example 1: Different driving modes correspond to different preset adjustment priorities. In the sport mode, the driver may pay more attention to the handling performance and response speed of the vehicle. At this time, the adjustment priorities for the yaw rate and sideslip angle of the center of mass that affect the vehicle steering stability are higher than the slip ratio to ensure the stability and handling performance of the vehicle during driving. In the economy mode, in order to achieve better fuel economy or electric energy utilization efficiency, it is necessary to ensure that the slip ratio of the wheels during braking is within a reasonable range and avoid energy loss caused by excessive slip. Therefore, the braking torque is preferentially adjusted according to the slip ratio.

[0042] Example 2: Different road surface conditions correspond to different preset adjustment priorities. On a dry and flat road surface, the adhesion between the vehicle and the ground is good. When braking on this road surface, the vehicle steering stability may be greatly affected. Therefore, the adjustment priority of the yaw rate is higher than the slip ratio. On a road surface with low adhesion coefficients such as wet, icy, etc., the wheels are prone to slip, and the change of the actual slip ratio is crucial for driving safety. Therefore, in this road surface condition, usually, the braking torque is preferentially adjusted according to the actual slip ratio, and then the braking torque is adjusted according to the actual yaw rate to prevent the wheels from locking or excessive slip and ensure the vehicle can drive safely on the road surface with low adhesion coefficients.

[0043] Example 3: Different vehicle types correspond to different preset adjustment priorities. For a small sedan, due to its characteristics such as a light body and a short wheelbase, during braking and steering, the changes in the sideslip angle of the center of mass and the yaw rate are relatively fast, which may have a greater impact on the vehicle's stability. Therefore, in a small sedan, the adjustment priorities corresponding to the actual sideslip angle of the center of mass and the actual yaw rate are relatively high, and the adjustment priority corresponding to the actual slip ratio is relatively low, so as to adjust the braking torque in a timely manner and maintain the vehicle's stability. For large vehicles such as large buses or heavy trucks, they have a large mass and large inertia, and the change in the slip ratio of the wheels during braking has a more significant impact on the braking effect and safety of the entire vehicle. Therefore, in such vehicles, the braking torque is preferentially adjusted according to the actual slip ratio to ensure effective braking of the wheels during braking and avoid vehicle out-of-control caused by too high a slip ratio.

[0044] Example 4: Different braking scenarios correspond to different preset adjustment priorities. In daily braking scenarios or straight-line braking scenarios, first, adjust the braking torque according to the slip ratio to ensure that the slip ratio of the wheels during braking is within a reasonable range; second, adjust the braking torque according to the yaw rate to ensure the stability of the vehicle during steering; finally, adjust the braking torque according to the sideslip angle of the center of mass to maintain the overall stability of the vehicle. In emergency braking scenarios or corner braking scenarios, the adjustment priority becomes to preferentially adjust the braking torque according to the yaw rate and the sideslip angle of the center of mass to ensure that the vehicle can stop as soon as possible and maintain a certain steering ability; then adjust the braking torque according to the slip ratio to avoid wheel lock-up.

[0045] In addition, the adjustment priority can also be determined according to the degree of difference between multiple actual stability parameters and their corresponding preset stability parameters. The greater the degree of difference, the higher the corresponding adjustment priority. For example, if the actual slip ratio exceeds the preset slip ratio by 20%, the actual yaw rate exceeds the preset yaw rate by 15%, and the actual sideslip angle of the center of mass exceeds the preset sideslip angle of the center of mass by 10%, then the braking torque is preferentially adjusted according to the slip ratio, then adjusted according to the yaw rate, and finally adjusted according to the sideslip angle of the center of mass.

[0046] Through the above technical solutions, by successively adjusting the braking torque of the vehicle according to the relationship between each actual stability parameter and its corresponding preset stability parameter, the stability of the vehicle during braking can be accurately controlled, avoiding wheel lock-up or sideslip phenomena caused by large adjustments of the braking torque, while reducing the abnormal intervention of ABS and ESC, and effectively improving the stability and safety of the vehicle in various braking scenarios.

[0047] In an optional implementation manner, the vehicle braking control method further includes: First, obtain the driving state parameters of the vehicle during braking.

[0048] In one embodiment, the driving state parameters include the longitudinal vehicle speed, lateral vehicle speed, vehicle speed (driving speed based on the longitudinal and lateral vehicle speeds), longitudinal acceleration, lateral acceleration, brake pedal depth, and steering wheel angle of the vehicle.

[0049] Then, according to the driving state parameters, an adjustment coefficient corresponding to each actual stability parameter is determined.

[0050] It should be noted that the driving state parameters are used to characterize the current driving state of the vehicle, such as the driving speed and steering situation. For each type of stability parameter, a corresponding adjustment coefficient is pre-calibrated based on at least multiple of different driving state parameters, vehicle design parameters, tire characteristics, road conditions, driving conditions, and vehicle performance of the vehicle.

[0051] Finally, after determining the adjustment coefficient corresponding to each actual stability parameter, step S12 above can be executed in the following manner: Successively, according to the relationship between each actual stability parameter and its corresponding preset stability parameter, the braking torque of the vehicle is adjusted step by step through the corresponding preset adjustment coefficient.

[0052] By adjusting the braking torque of the vehicle in the above manner, the braking system of the vehicle can more accurately adapt to the actual situation of the vehicle under different driving conditions, effectively maintain the stability of the vehicle, ensure driving safety, and optimize the handling performance of the vehicle.

[0053] Optionally, the multiple actual stability parameters include an actual slip ratio, an actual yaw rate, and an actual sideslip angle of the center of mass, and the preset stability parameters include a preset slip ratio corresponding to the actual slip ratio, a preset yaw rate corresponding to the actual yaw rate, and a preset sideslip angle of the center of mass corresponding to the actual sideslip angle of the center of mass.

[0054] In one implementation manner, to avoid the ABS and ESC intervening in the braking control of the vehicle and causing the vehicle to exit normal braking, the preset slip ratio is less than the slip ratio range corresponding to the triggering of the ABS, the preset yaw rate is less than the yaw rate range corresponding to the triggering of the ESC, and the preset sideslip angle of the center of mass is less than the sideslip angle of the center of mass range corresponding to the triggering of the ESC, so as to achieve the advance control of the braking torque of the vehicle.

[0055] The successively adjusting the braking torque of the vehicle step by step through the corresponding adjustment coefficient according to the relationship between each actual stability parameter and its corresponding preset stability parameter includes: In the first step, according to the relationship between the actual slip ratio and the preset slip ratio, the braking torque is subjected to a first-stage adjustment through the adjustment coefficient corresponding to the actual slip ratio.

[0056] In the second step, after the first-level adjustment is completed, according to the relationship between the actual yaw rate and the preset yaw rate, the braking torque is secondarily adjusted by an adjustment coefficient corresponding to the actual yaw rate.

[0057] In the third step, after the second-level adjustment is completed, according to the relationship between the actual sideslip angle of the center of mass and the preset sideslip angle of the center of mass, the braking torque is tertially adjusted by an adjustment coefficient corresponding to the actual sideslip angle of the center of mass.

[0058] It should be noted that the slip ratio is a key index for measuring the adhesion between the wheel and the ground during braking. When the actual slip ratio exceeds the reasonable range, the wheel may lock, resulting in the vehicle losing its steering ability and making it difficult to effectively control the braking torque of the vehicle. That is to say, when the actual slip ratio is too large, the adjustment of the braking torque for the actual yaw rate and the actual sideslip angle of the center of mass cannot be effectively carried out. Moreover, the three parameters of the slip ratio, yaw rate, and sideslip angle of the center of mass are interrelated and interact with each other, and adjusting one of them may cause changes in other parameters.

[0059] In view of this, the present disclosure exemplarily proposes a scheme for gradually adjusting the braking torque of a vehicle. The priority of the first-level adjustment is the highest, that is, the braking torque of the wheel is preferentially adjusted according to the actual slip ratio of the vehicle to ensure the adhesion of the tire during braking, avoid wheel locking, and ensure the effectiveness of subsequent adjustments. After the first-level adjustment is completed, the vehicle is secondarily adjusted, that is, the braking torque of the vehicle is adjusted according to the actual yaw rate of the vehicle to ensure the steering characteristics and driving stability of the vehicle, and avoid the sideslip and fishtailing phenomena of the vehicle. After each adjustment of the braking torque according to the actual yaw rate, the first-level adjustment is restarted to avoid the secondary adjustment affecting the actual slip ratio of the vehicle. When the actual slip ratio and the actual yaw rate of the vehicle are both within the set safety range, the tertiary adjustment of the vehicle is then carried out, that is, the braking torque of the vehicle is adjusted according to the actual sideslip angle of the center of mass of the vehicle to ensure that the vehicle is on a normal driving trajectory and avoid the sideslip and fishtailing phenomena of the vehicle. After each adjustment of the braking torque according to the actual sideslip angle of the center of mass, the first-level adjustment is restarted to avoid the tertiary adjustment affecting the actual slip ratio and the actual yaw rate of the vehicle.

[0060] In the above step-by-step adjustment scheme, the vehicle can monitor a variety of actual stability parameters of the vehicle in real time. Among them, an excessive actual yaw rate indicates that the vehicle may be about to experience side slip or fishtailing, and an excessive actual sideslip angle of the center of mass indicates that the vehicle may have deviated from the driving trajectory. Therefore, adjusting the braking torque of the vehicle based on the actual yaw rate first can avoid an excessive sideslip angle of the center of mass of the vehicle in advance, and then adjust the braking torque through the actual sideslip angle of the center of mass to correct the deviation of the vehicle during the braking torque adjustment process. This sequential adjustment method enables the vehicle braking system to more sensitively perceive the dynamic changes of the vehicle and improves the vehicle stability control ability.

[0061] By monitoring multiple actual stability parameters of the vehicle in real time through the above method and adjusting them step by step in sequence, it is possible to avoid a decrease in vehicle stability caused by an excessive one-time adjustment amplitude of the vehicle, and effectively avoid the influence on other stability parameters when adjusting the braking torque based on different stability parameters.

[0062] In another embodiment, the adjustment order for the actual yaw rate and the actual sideslip angle of the center of mass can be interchanged, or both can be executed simultaneously.

[0063] Optionally, the driving state parameters include the longitudinal vehicle speed and the steering wheel angle. The determining of the adjustment coefficient corresponding to each actual stability parameter according to the driving state parameters includes: First, determining a first adjustment coefficient k1 corresponding to the actual slip ratio according to the longitudinal vehicle speed. And Second, determining a second adjustment coefficient k2 corresponding to the actual yaw rate and a third adjustment coefficient k3 corresponding to the actual sideslip angle of the center of mass according to the steering wheel angle.

[0064] It should be noted that when a vehicle is traveling at a high speed, it usually has a large kinetic energy, and thus a greater braking force is required to decelerate. However, an excessive braking force may cause the wheels to break through the optimal adhesion state with the ground, increasing the slip ratio of the wheels. In this case, the first adjustment coefficient k1 can be determined based on the longitudinal vehicle speed and the actual slip ratio, aiming to adjust the braking torque in a timely manner to control the slip ratio within a reasonable range when the vehicle speed changes. In addition, the steering wheel angle directly reflects the driver's intention to control the driving direction of the vehicle. A large steering wheel angle means that the vehicle is performing a large-amplitude steering operation, which may cause the vehicle to rotate around the vertical axis and the offset of the center of mass position relative to the driving direction, respectively affecting the actual yaw rate and the actual sideslip angle of the center of mass. Determining the second adjustment coefficient k2 based on the steering wheel angle and the actual yaw rate, and determining the third adjustment coefficient k3 based on the steering wheel angle and the actual sideslip angle of the center of mass, is to ensure the steering stability and overall stability of the vehicle by adjusting the braking torque of the wheels to generate a torque in the opposite direction to the actual yaw rate or the actual sideslip angle of the center of mass when the actual yaw rate and the actual sideslip angle of the center of mass deviate from their corresponding preset ranges during the vehicle steering process.

[0065] Optionally, the first-level adjustment of the braking torque by the adjustment coefficient corresponding to the actual slip rate according to the relationship between the actual slip rate and the preset slip rate includes: When the actual slip rate of the target wheel is greater than the preset slip rate, the braking torque of the target wheel is reduced by the first adjustment coefficient until the actual slip rate of the target wheel is less than or equal to the preset slip rate, and it is determined that the first-level adjustment of the braking torque is completed. The target wheel is any wheel of the vehicle.

[0066] In one embodiment, by querying Table 1 shown below, the first adjustment coefficient k1 corresponding to different longitudinal vehicle speeds and different slip rates can be determined.

[0067] Table 1 (Longitudinal Vehicle Speed - Slip Rate - Adjustment Coefficient Relationship Table)

[0068] By adjusting the braking torque of the wheels by determining the first adjustment coefficient k1 according to the vehicle speed, the change of the slip rate during vehicle braking at different vehicle speeds can be effectively addressed. When traveling at a high speed, the risk of too rapid increase in the slip rate caused by the high kinetic energy due to the vehicle speed can be reduced in a timely manner, avoiding wheel lock-up and maintaining the steering and driving stability of the vehicle. When traveling at a low speed, since the vehicle speed is low and the kinetic energy of the vehicle is small, the corresponding first adjustment coefficient is small, which can reduce unnecessary braking torque adjustment while ensuring effective braking, improving the efficiency and comfort of the braking system.

[0069] In one embodiment, the vehicle is traveling on an ice and snow road surface at a speed of 60 km / h and braking. The preset slip ratio calibrated under the current driving state is set to 4%. At the initial stage of braking of the left front wheel, due to the large force exerted by the driver on the brake pedal and the extremely low adhesion of the ice and snow road surface, it is found through monitoring devices such as wheel speed sensors that the actual slip ratio of the left front wheel has reached 6%, which is significantly greater than the preset slip ratio. Then, the first adjustment coefficient k1 = 0.6 can be determined by querying Table 1 provided above, and the braking torque of the left front wheel is adjusted according to k1.

[0070] The specific adjustment method can be seen in the following calculation formula 1: Calculation formula 1: T2 = T1 * k1 Wherein, T1 is the braking torque of the target wheel before adjustment, and T2 is the braking torque of the target wheel after adjustment.

[0071] After each adjustment operation of the braking torque of the wheel is completed, the vehicle will also re-obtain the actual slip ratio of each wheel of the vehicle. If the actual slip ratio of any wheel still exceeds the preset slip ratio, the first adjustment coefficient k1 is determined again, and the braking torque of the wheel is adjusted based on the above calculation 1 until the actual slip ratio of each wheel is less than the preset slip ratio, then it is determined that the first-level adjustment of the vehicle is completed.

[0072] Through this first-level braking torque adjustment method based on the relationship between the actual slip ratio and the preset slip ratio, it is possible to effectively control the wheel slip situation during the braking process of the vehicle and ensure the braking stability and driving safety of the vehicle.

[0073] Optionally, the second-level adjustment of the braking torque according to the relationship between the actual yaw rate and the preset yaw rate, and by using the adjustment coefficient corresponding to the actual yaw rate, includes: When the actual yaw rate of the vehicle is greater than the preset yaw rate, the braking torque of the first target side wheel is increased through the second adjustment coefficient, and the first-level adjustment is executed again until the actual yaw rate of the vehicle is less than or equal to the preset yaw rate, and it is determined that the second-level adjustment of the braking torque is completed. The orientation of the first target side is opposite to the direction of the actual yaw rate.

[0074] In one embodiment, the second adjustment coefficient k2 corresponding to the current steering wheel angle and the actual yaw rate can be determined by querying Table 2 shown below.

[0075] Table 2 (Steering wheel angle - Yaw rate - Adjustment coefficient relationship table)

[0076] In one embodiment, after determining the second adjustment coefficient k2 corresponding to the steering wheel angle and the actual yaw rate of the vehicle, the wheels on the first target side can be adjusted by the second adjustment coefficient k2 respectively, that is, the front wheels and the rear wheels on the first target side are adjusted respectively, or the total braking torque of the vehicle on the first target side can be adjusted by the second adjustment coefficient k2, and then the adjusted total braking torque is distributed to the front wheels and the rear wheels on the first target side according to a preset distribution ratio.

[0077] Wherein, the first target side is the side of the vehicle body opposite to the side where the vehicle head yaws. It should be noted that the direction of the yaw rate of the vehicle is the rotation direction of the vehicle around its own vertical axis of the center of mass. If the vehicle rotates clockwise around its own vertical axis of the center of mass (viewed from above the vehicle), the direction of the yaw rate of the vehicle is defined as right. At this time, the first target side is the left side of the vehicle, and the wheels on the first target side are the left front wheel and the left rear wheel of the vehicle; if the vehicle rotates counterclockwise around its own vertical axis of the center of mass (viewed from above the vehicle), the direction of the yaw rate of the vehicle is defined as left. At this time, the first target side is the right side of the vehicle, and the wheels on the first target side are the right front wheel and the right rear wheel of the vehicle.

[0078] By determining the second adjustment coefficient k2 according to the steering wheel angle to adjust the braking torque, it is possible to effectively cope with the fluctuation of the actual yaw rate caused by the change of the steering wheel angle when the vehicle performs a steering operation. When the steering amplitude of the vehicle is large, timely adjusting the braking torque can avoid the situation of oversteering or understeering of the vehicle, and ensure the steering stability of the vehicle during steering operations such as cornering.

[0079] In one embodiment, the adjusted braking torque of the wheels on the target side can be determined by the following calculation formula 2: Calculation formula 2: T4 = T3 * (1 + k2) Wherein, T3 is the braking torque of the wheels on the first target side before adjustment, and T4 is the braking torque of the wheels on the first target side after adjustment.

[0080] Exemplarily, during the vehicle braking process, due to possible poor coordination of braking and steering by the driver during operation, the vehicle exhibits oversteering. The preset yaw rate calibrated under the current driving state is 2° / s (degrees per second), and the monitored actual yaw rate of the vehicle is 6° / s, which is greater than the preset yaw rate. Further monitoring shows that the current steering wheel angle of the vehicle is 60°. Then, the second adjustment coefficient k2 can be determined as 0.2 by querying Table 2 above, and the braking torque of the first target side wheels is increased through the above calculation formula 2. If the direction of the actual yaw rate of the vehicle is to the left, the first target side wheels are the right front wheel and the right rear wheel. If the original braking torque of the right front wheel is 300 N·m (Newton·meter) and the original braking torque of the right rear wheel is 400 N·m, the braking torque is adjusted once through the above calculation formula 2. The adjusted braking torque of the right front wheel is 360 N·m, and the adjusted braking torque of the right rear wheel is 480 N·m.

[0081] After completing one adjustment, the vehicle will continue to monitor the actual slip ratio of each wheel of the vehicle and the actual yaw rate of the vehicle in real time, and re-determine whether the actual slip ratio of each wheel is greater than the preset slip ratio. If it is greater, the braking torque of the target wheels is adjusted again through the above calculation formula 1 until the actual slip ratio of each wheel is less than or equal to the preset slip ratio. Then, it is determined again whether the current actual yaw rate of the vehicle is greater than the preset yaw rate. If it is greater, the braking torque of the first target side wheels is adjusted once again through the above calculation formula 2 until the actual slip ratio of each wheel of the vehicle is less than or equal to the preset slip ratio, and the actual yaw rate of the vehicle is less than the preset yaw rate, determining that the second-level adjustment of the vehicle is completed.

[0082] Through this method, the steering stability of the vehicle during braking can be effectively controlled, and the influence of adjusting the braking torque on the slip ratio and yaw rate of the vehicle is fully considered, thereby avoiding wheel locking and vehicle sideslip phenomena caused by changes in the braking torque and improving the braking safety of the vehicle.

[0083] Optionally, the third-level adjustment of the braking torque according to the relationship between the actual sideslip angle of the center of mass and the preset sideslip angle of the center of mass by using the adjustment coefficient corresponding to the actual sideslip angle of the center of mass includes: In the case where the actual sideslip angle of the center of mass of the vehicle is greater than the preset sideslip angle of the center of mass, the braking torque of the second target side wheels is increased through the third adjustment coefficient, and the first-level adjustment is executed again until the actual sideslip angle of the center of mass of the vehicle is less than or equal to the preset sideslip angle of the center of mass, determining that the third-level adjustment of the braking torque is completed. The orientation of the second target side is opposite to the direction of the actual sideslip angle of the center of mass.

[0084] In one embodiment, by querying Table 3 shown below, the third adjustment coefficient k3 corresponding to the current steering wheel angle and the actual centroid side slip angle can be determined.

[0085] Table 3 (Steering Wheel Angle - Centroid Side Slip Angle - Adjustment Coefficient Relationship Table)

[0086] In one embodiment, after determining the third adjustment coefficient k3, the wheels on the second target side can be adjusted respectively by the third adjustment coefficient k3, that is, the front wheels and rear wheels on the second target side are adjusted respectively, or the total braking torque of the vehicle on the second target side can be adjusted by the third adjustment coefficient k3, and then the adjusted total braking torque is distributed to the front wheels and rear wheels on the second target side according to a preset distribution ratio.

[0087] Among them, in the vehicle coordinate system, the centroid side slip angle is the angle by which the direction of the centroid velocity of the vehicle deviates from the direction of the vehicle longitudinal axis. When the vehicle is in a straight-line driving and ideal state without any lateral force interference, the centroid side slip angle is zero. When the driver turns the steering wheel for steering operation, the vehicle centroid will deviate from the original straight-line driving direction due to the generation of lateral force. If the vehicle turns left, the direction of the centroid side slip angle is clockwise (viewed from above the vehicle), that is, the direction of the centroid velocity vector deviates to the left relative to the vehicle longitudinal axis to form a clockwise included angle. In this case, the direction of the centroid side slip angle is defined as left, and the wheels on the second target side are the right front wheel and the right rear wheel of the vehicle; conversely, if the vehicle turns right, the direction of the centroid side slip angle is counterclockwise, and the centroid velocity vector deviates to the right relative to the vehicle longitudinal axis to form a counterclockwise included angle. In this case, the direction of the centroid side slip angle is defined as right, and the wheels on the second target side are the left front wheel and the left rear wheel of the vehicle.

[0088] Determining the third adjustment coefficient k3 according to the steering wheel angle and adjusting the braking torque helps to restore the overall stability of the vehicle in a timely manner when the centroid side slip angle deviates from the preset range due to the change of the steering wheel angle during the vehicle steering process. This can prevent the vehicle from experiencing side slip or fishtailing phenomena, ensure the safety of the vehicle during steering operations, and at the same time maintain good driving characteristics of the vehicle, such as ride comfort and the normal working state of various components.

[0089] In one embodiment, the adjusted braking torque of the wheels on the second target side can be determined by the following calculation formula 3: Calculation formula 3: T6 = T5 * (1 + k3) Among them, T5 is the braking torque of the wheels on the second target side before adjustment, and T6 is the braking torque of the wheels on the second target side after adjustment.

[0090] Exemplarily, the vehicle is turning left and braking on a wet road surface at a certain vehicle speed. Braking control is performed. The preset centroid side slip angle calibrated under the current driving state is 1.5°. The actual centroid side slip angle of the vehicle is monitored to be 3°, which is greater than the preset centroid side slip angle. Further monitoring shows that the current steering wheel angle of the vehicle is 40°. Then, the third adjustment coefficient k3 can be determined to be 0.4 by querying Table 3 above, and the braking torque of the second target side wheels is adjusted through the above calculation formula 3, that is, the braking torques of the right front wheel and the right rear wheel are adjusted. If the original braking torque of the right front wheel is 400 N·m and the original braking torque of the right rear wheel is 500 N·m, the braking torque is adjusted once through the above calculation formula 3. The adjusted braking torque of the right front wheel is 560 N·m, and the adjusted braking torque of the right rear wheel is 700 N·m.

[0091] After each adjustment is completed, the vehicle will continue to monitor the actual slip ratio of each wheel of the vehicle, the actual yaw rate, and the actual centroid side slip angle in real time, and re-execute the first-level adjustment, second-level adjustment, and third-level adjustment of the vehicle braking torque in sequence until the actual centroid side slip angle of the vehicle is less than or equal to the preset centroid side slip angle, and it is determined that the third-level adjustment of the vehicle braking torque is completed.

[0092] Through this method of adjusting the braking torque based on the relationship between the actual centroid side slip angle and the preset centroid side slip angle, the overall stability of the vehicle during driving and braking can be effectively controlled, ensuring the driving safety and normal operation of the vehicle.

[0093] Optionally, the method further includes: When the longitudinal vehicle speed of the vehicle is less than the preset vehicle speed threshold and the gear of the vehicle is in the parking gear, control the wheel of the vehicle to unload the braking torque.

[0094] In one implementation, refer to Figure 3 As shown, the braking torque of the vehicle during braking can be adjusted through the following steps.

[0095] S101. Obtain the actual slip ratio, actual yaw rate, and actual centroid side slip angle of the vehicle during braking.

[0096] S102. Determine whether the actual slip ratio is greater than the preset slip ratio.

[0097] If so, execute S103; if not, execute S104.

[0098] S103. Adjust the braking torque of the target wheel.

[0099] In one embodiment, when the actual slip ratio of the target wheel is greater than the preset slip ratio, first determine a first adjustment coefficient corresponding to the current longitudinal vehicle speed, and then adjust the braking torque of the target wheel through the first adjustment coefficient. The target wheel is any wheel in the vehicle.

[0100] After the adjustment is completed, return to execute S101.

[0101] S104. Determine whether the actual yaw rate is greater than the preset yaw rate.

[0102] If it is, execute S105; if not, execute S106.

[0103] S105. Adjust the braking torque of the first target side wheel.

[0104] In one embodiment, when the actual yaw rate of the vehicle is greater than the preset yaw rate, first determine a second adjustment coefficient corresponding to the steering wheel angle, and then adjust the braking torque of the first target side wheel through the second adjustment coefficient. The orientation of the first target side is opposite to the direction of the actual yaw rate.

[0105] After the adjustment is completed, return to execute S101.

[0106] S106. Determine whether the actual sideslip angle of the center of mass is greater than the preset sideslip angle of the center of mass.

[0107] If it is, execute S107; if not, execute S108.

[0108] S107. First determine a third adjustment coefficient corresponding to the steering wheel angle, and then adjust the braking torque of the second target side wheel through the third adjustment coefficient.

[0109] In one embodiment, when the actual sideslip angle of the center of mass of the vehicle is greater than the preset sideslip angle of the center of mass, first determine a third adjustment coefficient corresponding to the steering wheel angle, and then adjust the braking torque of the second target side wheel through the third adjustment coefficient. The orientation of the second target side is opposite to the direction of the actual sideslip angle of the center of mass.

[0110] After the adjustment is completed, return to execute S101.

[0111] S108. Determine whether the vehicle speed is less than the preset vehicle speed threshold and the vehicle gear is in the parking gear.

[0112] If it is, execute S109; if not, return to execute S101.

[0113] S109. Unload the braking torque of the wheel.

[0114] It should be noted that the preset vehicle speed threshold is a specific speed value preset in the vehicle control system, and its setting is usually based on factors such as the design characteristics of the vehicle, usage scenarios, and safety considerations. When the actual vehicle speed is lower than this threshold, it means that the vehicle is operating at a low speed or even almost stationary. For example, in some vehicles, the preset vehicle speed threshold may be set to 5 km / h or lower. Once the vehicle speed is lower than this value, it indicates that the vehicle can be regarded as stationary, and the parking gear is the P gear in the vehicle gears. The vehicle being in the parking gear can further ensure that the vehicle is in a parked state.

[0115] In one implementation, after determining that the vehicle is in a parked state by judging the vehicle speed and vehicle gear, the vehicle will control the hydraulic valve of the hydraulic brake to open the corresponding passage through the ECU (Electronic Control Unit), so that the hydraulic oil flows back to the liquid storage tank, thereby releasing the clamping force of the brake caliper on the wheel, completing the unloading of the hydraulic braking torque, and the ECU will adjust the current sent to the braking motor to zero, stopping the braking motor from working, and realizing the unloading of the electric braking torque.

[0116] Optionally, the vehicle includes a first electric brake, a second electric brake, and a hydraulic brake. The first electric brake corresponds to the front axle wheels of the vehicle, and the second electric brake corresponds to the rear axle wheels of the vehicle. Before obtaining multiple actual stability parameters of the vehicle during braking, the method further includes: The first step is to determine the total braking torque corresponding to the vehicle speed and the brake pedal depth.

[0117] In one implementation, when the driver steps on the brake pedal while the vehicle is moving, expecting the vehicle to decelerate or stop, the main brake controller of the vehicle receives the wheel speed information collected by the wheel speed sensors of the four wheels, the actual yaw rate, longitudinal acceleration, and lateral acceleration collected by the yaw rate sensor, and the brake pedal depth collected by the brake pedal travel sensor, and comprehensively determines the vehicle speed through the wheel speed information of the four wheels, the actual yaw rate of the vehicle, longitudinal acceleration, and lateral acceleration.

[0118] For example, input the wheel speed information of the four wheels at the current moment and the actual yaw rate of the vehicle into the vehicle dynamics model to obtain the vehicle speed at the current moment. At the same time, based on the vehicle speed at the previous moment and combined with the lateral acceleration and longitudinal acceleration collected by the yaw rate sensor, the vehicle speed at the current moment can be estimated. Subsequently, verify the vehicle speed output by the vehicle dynamics model with the estimated vehicle speed to clarify the vehicle speed at the current moment.

[0119] After determining the vehicle speed and brake pedal depth at the current moment, the total braking torque of the vehicle at the current moment can be determined by querying the pre-calibrated braking torque table of the vehicle. The braking torque table includes the total braking torque of the vehicle corresponding to different brake pedal depths at different vehicle speeds.

[0120] In the second step, distribute the total braking torque to the front axle wheels and the rear axle wheels of the vehicle according to a preset distribution ratio.

[0121] It should be noted that there are differences in the load borne by the front and rear axles of the vehicle during braking, the impact on vehicle stability, and the adhesion characteristics with the ground. Therefore, it is necessary to calibrate a suitable preset distribution ratio according to factors such as the design characteristics of the vehicle, the weight distribution of the front and rear axles, and the adhesion between the tires and the ground, so that the front and rear axle wheels can work together during braking, ensuring that the vehicle can effectively decelerate and stop while maintaining good driving stability.

[0122] For example, in a front-wheel drive vehicle, the main components such as the engine or motor are located at the front of the vehicle, and usually the front axle bears a relatively large weight; while in a rear-wheel drive vehicle, the engine or motor is at the rear of the vehicle, and the rear axle weight accounts for a relatively large proportion. The weight distribution will affect the braking torque that the front and rear axle wheels need to bear during braking. Generally speaking, the axle with a larger weight needs to bear relatively more braking torque during braking to ensure the overall balance and stable braking of the vehicle. Taking a front-wheel drive vehicle as an example, the front axle bears about 60% of the weight and the rear axle bears about 40% of the weight. In this case, the preset distribution ratio may tend to let the front axle wheels bear relatively more braking torque. For example, the front axle distribution ratio is set to 65% and the rear axle is 35%.

[0123] In addition, the preset distribution ratio is also related to the driving conditions of the vehicle. For example, during straight braking, the front and rear axle wheels distribute the braking torque according to the first preset distribution ratio to make the vehicle decelerate smoothly; during turning braking, according to the dynamic conditions of the vehicle, such as the steering wheel angle, yaw rate, and sideslip angle of the center of mass, determine the second preset distribution ratio, and adjust the braking torque distribution ratio of the front and rear axle wheels in real time to ensure the stability and controllability of the vehicle during turning.

[0124] In the third step, sequentially distribute the braking torque allocated to the front axle wheels to the first electric motor brake and the hydraulic brake, and sequentially distribute the braking torque allocated to the rear axle wheels to the second electric motor brake and the hydraulic controller.

[0125] Among them, the front axle wheels include the left front wheel and the right front wheel, and the rear axle wheels include the left rear wheel and the right rear wheel. In a vehicle with multiple electric motor brakes, both the first electric motor brake and the second electric motor brake can include multiple motors.

[0126] In an embodiment, after the total braking torque of the vehicle is distributed to the front axle wheels and the rear axle wheels according to a preset distribution ratio, the front axle wheels and the rear axle wheels then evenly distribute the allocated braking torque to the wheels on their respective left and right sides, that is, the braking torque allocated to each wheel can be obtained. For each wheel, braking is preferentially performed through its corresponding electric motor brake. When the corresponding electric motor brake of itself cannot meet the current braking torque requirement, the remaining braking torque is output through other brakes. Among them, the other brakes can be at least one of a hydraulic brake, a mechanical brake, and a pneumatic brake.

[0127] By preferentially using the electric motor brake for regenerative braking, the energy utilization rate of the vehicle is improved, and the mechanical wear of the vehicle is reduced.

[0128] Take Figure 2 The three-motor braking system shown is used for exemplary illustration. The front motor controller is the first motor controller corresponding to the front axle wheels, and the left rear motor controller and the right rear motor controller are the second motor controllers corresponding to the rear axle wheels. If the main braking controller calculates that the total braking torque of the vehicle at the current moment is 1000 N·m, and the preset distribution ratio of the vehicle is 60% for the front axle and 40% for the rear axle, then the braking torque allocated to the front axle wheels is 600 N·m, where the braking torque allocated to the left front wheel and the right front wheel is both 300 N·m, and the braking torque allocated to the rear axle wheels is 400 N·m, where the braking torque allocated to the left rear wheel and the right rear wheel is both 200 N·m. The main braking controller preferentially uses the front motor controller, the left rear motor controller, and the right rear motor controller for regenerative braking. If the maximum regenerative braking torque that each motor controller can generate is 300 N·m, then the rear side wheels do not require the intervention of the hydraulic brake for braking. However, the left front wheel and the right front wheel can only generate a regenerative braking torque of 150 N·m through motor regenerative braking, then the hydraulic brake can be called in for braking, and the left front wheel and the right front wheel respectively generate a braking torque of 150 N·m through the hydraulic brake for braking.

[0129] In addition, in the case of a failure or malfunction of any electric motor brake of the vehicle, the braking torque of the corresponding wheel can be provided by other brakes, providing a fault redundancy guarantee for the vehicle braking system. Even if a certain electric motor brake has a problem, the vehicle can still rely on other backup brakes such as hydraulic brakes to maintain normal braking function.

[0130] Through the above solution, in terms of accurately determining the total braking torque, reasonably distributing the total braking torque, coordinating multiple braking methods, and providing fault redundancy guarantee, etc., the performance, stability, and safety of the vehicle braking system are comprehensively improved, better meeting the braking requirements of the vehicle in various driving scenarios.

[0131] Figure 4 is a block diagram of a vehicle braking control device proposed according to an exemplary embodiment. Refer to Figure 4 As shown, the vehicle control device 500 includes: an acquisition module 501 and an adjustment module 502.

[0132] The acquisition module 501 is configured to acquire a plurality of actual stability parameters of the vehicle during braking.

[0133] The adjustment module 502 is configured to sequentially adjust the braking torque of the vehicle step by step according to the relationship between each actual stability parameter and its corresponding preset stability parameter.

[0134] Optionally, the acquisition module 501 is configured to: acquire the driving state parameters of the vehicle during braking; determine an adjustment coefficient corresponding to each actual stability parameter according to the driving state parameters.

[0135] The adjustment module 502 is configured to: sequentially adjust the braking torque of the vehicle step by step according to the relationship between each actual stability parameter and its corresponding preset stability parameter through their corresponding preset adjustment coefficients.

[0136] Optionally, the plurality of actual stability parameters include an actual slip ratio, an actual yaw rate, and an actual sideslip angle of the center of mass, and the preset stability parameters include a preset slip ratio corresponding to the actual slip ratio, a preset yaw rate corresponding to the actual yaw rate, and a preset sideslip angle of the center of mass corresponding to the actual sideslip angle of the center of mass.

[0137] The adjustment module 502 is configured to: perform a first-level adjustment on the braking torque according to the relationship between the actual slip ratio and the preset slip ratio through the adjustment coefficient corresponding to the actual slip ratio; after the first-level adjustment is completed, perform a second-level adjustment on the braking torque according to the relationship between the actual yaw rate and the preset yaw rate through the adjustment coefficient corresponding to the actual yaw rate; after the second-level adjustment is completed, perform a third-level adjustment on the braking torque according to the relationship between the actual sideslip angle of the center of mass and the preset sideslip angle of the center of mass through the adjustment coefficient corresponding to the actual sideslip angle of the center of mass.

[0138] Optionally, the driving state parameters include a longitudinal vehicle speed and a steering wheel angle, and the acquisition module 501 is configured to: determine a first adjustment coefficient corresponding to the actual slip ratio according to the longitudinal vehicle speed.

[0139] Determine a second adjustment coefficient corresponding to the actual yaw rate and a third adjustment coefficient corresponding to the actual sideslip angle of the center of mass according to the steering wheel angle.

[0140] Optionally, the adjustment module 502 is configured to: When the actual slip ratio of the target wheel is greater than the preset slip ratio, reduce the braking torque of the target wheel by the first adjustment coefficient until the actual slip ratio of the target wheel is less than or equal to the preset slip ratio, and determine that the first-stage adjustment of the braking torque is completed. The target wheel is any wheel of the vehicle.

[0141] Optionally, the adjustment module 502 is configured to: When the actual yaw rate of the vehicle is greater than the preset yaw rate, increase the braking torque of the first target side wheels by the second adjustment coefficient, and return to execute the first-stage adjustment until the actual yaw rate of the vehicle is less than or equal to the preset yaw rate, and determine that the second-stage adjustment of the braking torque is completed. The orientation of the first target side is opposite to the direction of the actual yaw rate.

[0142] Optionally, the adjustment module 502 is configured to: When the actual sideslip angle of the center of mass of the vehicle is greater than the preset sideslip angle of the center of mass, increase the braking torque of the second target side wheels by the third adjustment coefficient, and return to execute the first-stage adjustment until the actual sideslip angle of the center of mass of the vehicle is less than or equal to the preset sideslip angle of the center of mass, and determine that the third-stage adjustment of the braking torque is completed. The orientation of the second target side is opposite to the direction of the actual sideslip angle of the center of mass.

[0143] Optionally, the adjustment module 502 is configured to: When the longitudinal vehicle speed is less than the preset vehicle speed threshold and the gear of the vehicle is in the parking gear, control the wheel of the vehicle to unload the braking torque.

[0144] Optionally, the vehicle includes a first electric motor brake, a second electric motor brake, and a hydraulic brake. The first electric motor brake corresponds to the front axle wheels of the vehicle, and the second electric motor brake corresponds to the rear axle wheels of the vehicle. The adjustment module 502 is configured to: Determine the total braking torque corresponding to the vehicle speed and the braking pedal depth; Distribute the total braking torque to the front axle wheels and the rear axle wheels of the vehicle according to a preset distribution ratio; The braking torque allocated to the front axle wheels is sequentially distributed to the first electric motor brake and the hydraulic brake, and the braking torque allocated to the rear axle wheels is sequentially distributed to the second electric motor brake and the hydraulic controller.

[0145] Regarding the device in the above embodiments, the specific manners in which each module performs operations have been described in detail in the embodiments related to the method, and will not be elaborated herein.

[0146] Based on the same inventive concept, an exemplary embodiment of the present disclosure further provides a controller, which includes: A memory storing a computer program thereon; A processor configured to execute the computer program in the memory to implement the vehicle braking control method provided by the present disclosure.

[0147] Based on the same inventive concept, an exemplary embodiment of the present disclosure further provides a vehicle configured with the controller provided by the present disclosure to execute the vehicle braking control method provided by the present disclosure.

[0148] Figure 5 FIG. is a block diagram of a vehicle 600 shown according to an exemplary embodiment. For example, the vehicle 600 may be a hybrid vehicle, or a non - hybrid vehicle, an electric vehicle, a fuel cell vehicle, or other types of vehicles. The vehicle 600 may be an autonomous vehicle, a semi - autonomous vehicle, or a non - autonomous vehicle.

[0149] Referring to Figure 5 , the vehicle 600 may include various subsystems. For example, the infotainment system 610, the perception system 620, the decision - making and control system 630, the drive system 640, and the computing platform 650. Among them, the vehicle 600 may further include more or fewer subsystems, and each subsystem may include multiple components. In addition, each subsystem and each component of the vehicle 600 may be interconnected in a wired or wireless manner.

[0150] In some embodiments, the infotainment system 610 may include a communication system, an entertainment system, and a navigation system, etc.

[0151] The perception system 620 may include several sensors for sensing information about the environment around the vehicle 600. For example, the perception system 620 may include a global positioning system (the global positioning system may be a GPS system, or a Beidou system, or other positioning systems), an inertial measurement unit (IMU), lidar, millimeter - wave radar, ultrasonic radar, and a camera device.

[0152] The decision control system 630 may include a computing system, a vehicle controller, a steering system, an accelerator, and a braking system.

[0153] The drive system 640 may include components that provide powered movement for the vehicle 600. In one embodiment, the drive system 640 may include an engine, an energy source, a powertrain, and wheels. The engine may be one or a combination of an internal combustion engine, an electric motor, and an air compression engine. The engine is capable of converting the energy provided by the energy source into mechanical energy.

[0154] Some or all of the functions of the vehicle 600 are controlled by the computing platform 650. The computing platform 650 may include at least one processor 651 and a memory 652, and the processor 651 may execute instructions 653 stored in the memory 652.

[0155] The processor 651 may be any conventional processor, such as a commercially available CPU. The processor may also include, for example, a Graphic Process Unit (GPU), a Field Programmable Gate Array (FPGA), a System on Chip (SOC), an Application Specific Integrated Circuit (ASIC), or a combination thereof.

[0156] The memory 652 may be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Read-Only Memory (PROM), Read-Only Memory (ROM), magnetic memory, flash memory, a magnetic disk, or an optical disk.

[0157] In addition to the instructions 653, the memory 652 may also store data, such as road maps, route information, data on the position, direction, speed, etc. of the vehicle. The data stored in the memory 652 can be used by the computing platform 650.

[0158] The preferred embodiments of the present disclosure have been described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0159] In addition, it should be noted that, in the above specific embodiments, the various specific technical features described can be combined in any suitable manner without conflict. To avoid unnecessary repetition, the present disclosure will not separately describe various possible combinations.

[0160] Furthermore, any combination can be made among the various different embodiments of the present disclosure, as long as it does not violate the idea of the present disclosure, and it should also be regarded as the content disclosed by the present disclosure.

Claims

1. A vehicle braking control method, characterized in that The method includes: Obtaining a plurality of actual stability parameters during the braking process of the vehicle; Sequentially adjusting the braking torque of the vehicle step by step according to the relationship between each actual stability parameter and its corresponding preset stability parameter.

2. The method according to claim 1, characterized in that, The method further includes: Obtaining the driving state parameters of the vehicle during the braking process; Determining an adjustment coefficient corresponding to each actual stability parameter according to the driving state parameters; The sequentially adjusting the braking torque of the vehicle step by step according to the relationship between each actual stability parameter and its corresponding preset stability parameter includes: Sequentially adjusting the braking torque of the vehicle step by step according to the relationship between each actual stability parameter and its corresponding preset stability parameter through their respective preset adjustment coefficients.

3. The method according to claim 2, characterized in that, The plurality of actual stability parameters include an actual slip ratio, an actual yaw rate, and an actual sideslip angle of the center of mass, and the preset stability parameters include a preset slip ratio corresponding to the actual slip ratio, a preset yaw rate corresponding to the actual yaw rate, and a preset sideslip angle of the center of mass corresponding to the actual sideslip angle of the center of mass; The sequentially adjusting the braking torque of the vehicle step by step according to the relationship between each actual stability parameter and its corresponding preset stability parameter through their respective adjustment coefficients includes: Performing a first-level adjustment on the braking torque according to the relationship between the actual slip ratio and the preset slip ratio through the adjustment coefficient corresponding to the actual slip ratio; After the first-level adjustment is completed, performing a second-level adjustment on the braking torque according to the relationship between the actual yaw rate and the preset yaw rate through the adjustment coefficient corresponding to the actual yaw rate; After the second-level adjustment is completed, performing a third-level adjustment on the braking torque according to the relationship between the actual sideslip angle of the center of mass and the preset sideslip angle of the center of mass through the adjustment coefficient corresponding to the actual sideslip angle of the center of mass.

4. The method according to claim 3, characterized in that, The driving state parameters include a longitudinal vehicle speed and a steering wheel angle, and the determining an adjustment coefficient corresponding to each actual stability parameter according to the driving state parameters includes: Determining a first adjustment coefficient corresponding to the actual slip ratio according to the longitudinal vehicle speed; and Determining a second adjustment coefficient corresponding to the actual yaw rate and a third adjustment coefficient corresponding to the actual sideslip angle of the center of mass according to the steering wheel angle.

5. The method according to claim 4, wherein The performing a first-level adjustment on the braking torque according to the relationship between the actual slip ratio and the preset slip ratio through the adjustment coefficient corresponding to the actual slip ratio includes: In the case where the actual slip ratio of the target wheel is greater than the preset slip ratio, reducing the braking torque of the target wheel through the first adjustment coefficient until the actual slip ratio of the target wheel is less than or equal to the preset slip ratio, and determining that the first-level adjustment of the braking torque is completed, where the target wheel is any wheel of the vehicle.

6. The method according to claim 4, wherein The performing a second-level adjustment on the braking torque according to the relationship between the actual yaw rate and the preset yaw rate through the adjustment coefficient corresponding to the actual yaw rate includes: When the actual yaw rate of the vehicle is greater than the preset yaw rate, increase the braking torque of the first target side wheels through the second adjustment coefficient, and return to execute the first-level adjustment until the actual yaw rate of the vehicle is less than or equal to the preset yaw rate, and determine that the second-level adjustment of the braking torque is completed. The orientation of the first target side is opposite to the direction of the actual yaw rate.

7. The method according to claim 4, characterized in that, The third-level adjustment of the braking torque according to the relationship between the actual center-of-mass sideslip angle and the preset center-of-mass sideslip angle includes: When the actual center-of-mass sideslip angle of the vehicle is greater than the preset center-of-mass sideslip angle, increase the braking torque of the second target side wheels through the third adjustment coefficient, and return to execute the first-level adjustment until the actual center-of-mass sideslip angle of the vehicle is less than or equal to the preset center-of-mass sideslip angle, and determine that the third-level adjustment of the braking torque is completed. The orientation of the second target side is opposite to the direction of the actual center-of-mass sideslip angle.

8. The method according to any one of claims 1-7, characterized in that, The method further includes: When the longitudinal vehicle speed is less than a preset speed threshold and the gear of the vehicle is in the parking gear, control the wheels of the vehicle to unload the braking torque.

9. The method according to claim 1, wherein The vehicle includes a first electric motor brake, a second electric motor brake, and a hydraulic brake. The first electric motor brake corresponds to the front axle wheels of the vehicle, and the second electric motor brake corresponds to the rear axle wheels of the vehicle. Before obtaining multiple actual stability parameters of the vehicle during braking, the method further includes: Determine the total braking torque corresponding to the vehicle speed and the braking pedal depth; Distribute the total braking torque to the front axle wheels and the rear axle wheels of the vehicle according to a preset distribution ratio; Sequentially distribute the braking torque allocated to the front axle wheels to the first electric motor brake and the hydraulic brake, and sequentially distribute the braking torque allocated to the rear axle wheels to the second electric motor brake and the hydraulic controller.

10. A controller, characterized in that, including: A memory, on which a computer program is stored; A processor for executing the computer program in the memory to implement the method according to any one of claims 1-9.

11. A vehicle, characterized in that, The vehicle is configured with a controller as claimed in claim 10.

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